KR100219189B1 - Nickel-hydrogen secondary battery and its manufacturing method - Google Patents

Abstract

The present invention relates to a method for producing a nickel-hydrogen secondary battery and a nickel-hydrogen secondary battery having a separator including polyolefin-based synthetic resin fibers having excellent stability and having improved charge-discharge cycle life. The secondary battery includes a separator including a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a polyolefin-based synthetic resin fiber having an ion exchange group interposed between the positive electrode and the negative electrode, When the ion exchange amount per battery capacity lAh of the separator is set to X (meq / Ah) with an alkali electrolyte solution of about 5 s or more, and the alkaline electrolyte equivalent per battery capacity of 1Ah is Y (meq / Ah) Amount (Y) is represented by the following formula (1)

{0.409- (X / 55)} ≦ Y ≦ {0.636+ (2X / 55)}... (One)

It is characterized by satisfying.

Description

Manufacturing method of nickel hydrogen secondary battery and nickel hydrogen secondary battery

1 is a perspective view showing a Nigel hydrogen secondary battery of the present invention.

2 is a plan view showing a manufacturing process of the separator of the present invention.

3 is a cross-sectional view taken along the line III-III-In of FIG.

4 is a magnified plan view of FIG.

5 is a characteristic diagram showing a change in cycle life when the ion exchange amount (Y) of the separator in the nickel-hydrogen secondary batteries of Examples l2 to 15 and Comparative Examples 4 to 6 of the present invention is changed.

6 is a characteristic diagram showing the relationship between ion exchange amount (Y), alkali electrolyte equivalent (X) and cycle life in the nickel-hydrogen secondary batteries of Examples 1 to 21 and Comparative Examples 1 to 21 of the present invention.

7 is a characteristic diagram showing the relationship between the ion exchange amount (Y) and the alkali electrolyte equivalent amount (X) and the cycle life in the nickel-hydrogen secondary batteries of Examples 22 to 38 and Comparative Examples 22 to 39 of the present invention.

8 is a characteristic diagram showing a change in cycle life when the ion exchange amount (Y) of a separator in the nickel-hydrogen secondary batteries of Examples 39 to 42 and Comparative Examples 40 to 42 of the present invention is changed.

9 is a characteristic diagram showing a change in cycle life when the ion exchange amount (Y) of a separator in the nickel-hydrogen secondary batteries of Examples 43 to 46 and Comparative Examples 43 to 45 of the present invention is changed.

10 is a characteristic diagram showing the relationship between the cycle water ratio and the discharge capacity ratio in the nickel-hydrogen secondary batteries of Examples 50 to 55 of the present invention.

11 is a characteristic diagram showing the relationship between the cycle water ratio and the discharge capacity ratio in the Nigel hydrogen secondary batteries of Comparative Examples 50 to 55;

12 is a characteristic diagram showing the relationship between the capacity retention rate and the lithium hydroxide concentration in the electrolyte solution in the nickel-hydrogen secondary batteries of Examples 70 to 75 and Comparative Examples 70 and 71 of the present invention.

Fig. 13 is a characteristic diagram showing the relationship between the capacity retention rate and the sodium hydroxide concentration in the electrolyte solution in the nickel-hydrogen secondary batteries of Examples 76 to 81 and Comparative Examples 70 and 71 of the present invention.

14 is a characteristic diagram showing the relationship between the capacity retention rate and the ion exchange amount of a separator in the nickel-hydrogen secondary batteries of Examples 82 to 84 and Comparative Example 72 of the present invention.

FIG. 15 is a characteristic diagram showing the relationship between the capacity remaining rate and the amount of profit exchange of a separator in the nickel-hydrogen secondary batteries of Examples 85 to 87 and Comparative Example 74 of the present invention. FIG.

Fig. 16 is a characteristic diagram showing the relationship between the capacity retention rate and the lithium hydroxide concentration in the electrolyte in the nickel-hydrogen secondary batteries of Examples 88 to 93 and Comparative Examples 71 and 78 of the present invention.

Fig. 17 is a characteristic diagram showing the relationship between the capacity retention rate and the sodium hydroxide concentration in the electrolyte solution in the nickel-hydrogen secondary batteries of Examples 94 to 99 and Comparative Examples 71 and 78 of the present invention.

18 is a cross-sectional view showing a battery breakdown voltage measuring device for measuring the battery breakdown voltage in the nickel-metal hydride secondary batteries of Examples 88 to 99 and Comparative Examples 70 and 71 of the present invention.

19 is a characteristic diagram showing the relationship between the storage days at high temperatures and the capacity remaining rate in Example 100 of the present invention.

20 is a characteristic diagram showing the relationship between the cycle water ratio and the discharge capacity ratio in the nickel-hydrogen secondary batteries of Examples 110 to 112 and Comparative Examples 80 to 81 of the present invention.

* Explanation of symbols for main parts of the drawings

1: container 2: positive pole

3: Separator 4: Minus pole

5 electrode group 6 hole

7: sealing plate 8: gasket

9: positive pole lead 10: positive pole terminal

11: safety valve 12: pressing plate

13: outer tube 21: sheet-like

22: first page 23: second page

24: recessed portion 25: film portion

31: case body 32: cap

33: Space 34: King

35: O-ring 36: Bolt

37: nut 38: pressure detector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a nickel hydride secondary battery and a nickel hydride secondary battery. In particular, a method for manufacturing a nickel hydride secondary battery and a nickel hydride secondary battery in which a separator interposed between a positive electrode and a negative electrode is improved. Related to.

As a nickel-hydrogen secondary battery, an electrode group produced by sandwiching a separator between a paste type positive electrode containing nickel hydroxide and a paste type negative electrode containing hydrogen storage alloy is stored in a container together with an alkali electrolyte solution. have. The secondary battery has a voltage compatibility with a Nigel cadmium secondary battery having a negative electrode containing a cadmium compound instead of the hydrogen storage alloy, and also has excellent characteristics of higher capacity than the nickel cadmium secondary battery.

Among the constituent members of the nickel-hydrogen secondary battery, a separator may be made of a polyamide-based fiber which has been commonly used in nickel-cadmium secondary batteries. However, in this separator, impurities (for example, nitrate ions, nitrite ions, and ammonia) generated by hydrolysis in an alkaline electrolyte solution accelerate the self discharge by repeating the oxidation reaction at the positive electrode and the reduction reaction at the negative electrode. It is known that there is a problem.

As such, forming a separator is more widely used in nickel-hydrogen secondary batteries, in which hydrophilization is applied to polyolefin-based synthetic resin fibers which are more stable in alkaline electrolyte but are basically hydrophobic. As the method of hydrophilization treatment, sulfonation treatment, graft copolymerization treatment with hydrophilic polymers and the like are known. However, in such a conventional nickel-metal hydride secondary battery, there is a demand for an increase in charge and discharge cycle life.

On the other hand, in Example 4 of International Patent Application Publication No. VO 93/01622, an ion exchange capacity of 0.48 (meq) formed by graft copolymerization of acrylic acid on a nonwoven fabric composed of polypropylene short fibers having a fiber diameter of 5 to 10 was obtained. A nickel hydride secondary battery using a separator of / g) and using 30% potassium hydroxide as an electrolyte is disclosed.

Japanese Laid-Open Patent Publication No. 94-19641 discloses graft polymerization of at least one vinyl monomer selected from acrylic acid and methacrylic acid on a woven or nonwoven fabric made of polyolefin resin fibers as a separator for nickel-hydrogen secondary batteries. It is disclosed that the carboxyl group of the branched polymer by vinyl monomer is used in the form of a salt with cation of the same kind as present in the electrolyte. Example 1 of this publication describes that when a potassium hydroxide aqueous solution having a specific gravity of 1.28 is used as the alkaline electrolyte, a separator in which potassium hydroxide aqueous solution treatment is applied to a nonwoven fabric grafted with acrylic acid is used.

Further, Tanaka et al. (5,290,645) in US Patent Publication discloses a battery separator composed of a sheet material comprising polyvinyl alcohol crosslinked by a crosslinking group having a specific structural formula. It is also disclosed that the sheet material has a hydrophilic part and a hydrophobic part.

An object of the present invention is to provide a method for producing a nickel-hydrogen secondary battery and a nickel-hydrogen secondary battery having a separator containing polyolefin-based synthetic resin fibers with excellent stability and improved charge-discharge cycle summing.

An object of the present invention is to provide a nickel-hydrogen secondary battery with improved self-discharge characteristics at high temperature storage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a nickel-hydrogen secondary battery that has achieved a long life by suppressing an increase in the battery internal pressure during overcharge and reverse charge.

According to the present invention, a separator comprising a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a polyolefin-based synthetic resin fiber having an ion exchange group interposed between the positive electrode and the negative electrode, and a concentration; When the ion electrolyte amount per 1 Ah of the battery capacity is set to X (meq / Ah) and the alkali electrolyte solution equivalent to 5 or more alkali electrolytes and the battery capacity of 1 Ah is set to Y (meq / Ah), the said ion Exchange amount (Y) is represented by the following formula (1)

A nickel-hydrogen secondary battery that satisfies the above is provided.

According to the present invention, there is provided a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkali electrolyte solution. There is provided a nickel-hydrogen secondary battery which is formed by forming an ion exchanger in the form of a salt by treating a sheet-like material containing polyolefin-based synthetic resin fibers with an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte.

According to the present invention, a nickel-hydrogen secondary battery comprising a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkaline electrolyte solution. A manufacturing method, comprising: graft co-polymerizing a vinyl monomer having ionic groups by irradiating ultraviolet rays to a sheet-like article containing polyolefin-based synthetic resin fibers containing no light stabilizer; and alkalinizing the sheet-like article with the same kind and concentration ratio as the alkali electrolyte. A method for producing a nickel-hydrogen secondary battery for producing the separator is provided by a method having a step of treating with an aqueous solution.

According to the present invention, there is also provided a positive electrode including a nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkaline electrolyte, wherein the suction has an ion exchange group. When the average diameter of all the fibers constituting the separator is X µm, and the ion exchange amount of the separator is Ymeq / g, which is formed into a sheet-like material containing polyolefin-based synthetic resin fibers, they are represented by the following formulas (2) and (3). Satisfies the formula,

The alkali electrolyte is provided with a nickel-hydrogen secondary battery comprising at least one of lithium hydroxide or sodium hydroxide.

In addition, according to the present invention, a positive electrode including nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator, and an alkali electrolyte solution, the separator comprises a sheet containing a water-repellent synthetic resin fiber and a synthetic resin fiber having hydrophilicity And a separator comprising a sheet including a water repellent synthetic resin fiber disposed between the plus electrode and the minus electrode such that the sheet is positioned at the minus electrode. do.

The nickel-hydrogen secondary battery according to the present invention is a polyolefin-based synthetic resin fiber having an ion exchange group interposed between a positive electrode containing nickel hydroxide and a negative electrode containing a hydrogen storage alloy, and a positive electrode and the negative electrode. And an alkali electrolyte solution having a concentration of about 5 s or more, and an alkali electrolyte equivalent weight per battery capacity of 1 Ah, with X (meq / Ah), and an ion exchange amount of Y (meq / Ah) per battery capacity of 1 Ah of the separator. When the ion exchange amount (Y) is represented by the following formula (1),

To satisfy.

Hereinafter, the nickel-hydrogen secondary battery (for example, cylindrical nickel-hydrogen secondary battery) according to the present invention will be described with reference to FIG.

In the bottomed cylindrical container 1, the electrode group 5 produced by laminating | stacking and winding the positive electrode 2, the separator 3, and the negative electrode 4 in spiral shape is accommodated. The negative electrode 4 is disposed at the outermost circumference of the electrode group 5 to be in electrical contact with the container 1. The alkaline electrolyte is contained in the container 1. A circular first sealing plate 7 having a hole 6 in the center is disposed at the upper opening of the container 1. A ring-shaped insulating gasket 8 is disposed between the circumferential frame of the sealing plate 7 and the inner surface of the upper opening of the container 1, and is sucked into the container 1 by suction to reduce the diameter of the upper opening inside. The sealing plate 7 is hermetically fixed through the gasket 8. One end of the positive electrode lead 9 is connected to the positive electrode 2, and the other end thereof is connected to the bottom surface of the sealing plate 7. The positive electrode terminal 10 having a hat shape is attached to the sealing plate 7 so as to cover the hole 6. A rubber safety valve 11 is arranged to close the hole 6 in a space surrounded by the sealing plate 7 and the positive electrode terminal 10. The circular pressing plate 12 made of an insulating material having a hole in the center is disposed on the positive pole terminal 10 such that the protrusion of the positive pole terminal 10 protrudes from the hole of the pressing plate 12. The outer tube 13 covers the circumferential frame of the pressing plate 12, the side surface of the container 1, and the bottom circumference of the container 1.

Next, the positive curve 2, the negative electrode 4, the separator 3 and the electrolyte solution will be described.

1) plus pole (2)

The positive electrode 2 can be produced by, for example, adding a conductive material to a nickel hydroxide powder which is an active material, stirring the polymer binder and the mixture together to prepare a paste, filling the paste into a conductive substrate, drying and molding the paste. have.

As said nickel hydroxide, you may use nickel hydroxide in which zinc and cobalt were co-precipitated.

Examples of the conductive material include cobalt oxides such as CoO, cobalt hydroxides such as Co (OH) _2, and metal cobalt. Especially, it is preferable to use Co0, Co (OH) ₂ .

Examples of the polymer binder include polytetrafluoroerylene (PTFE), polyethylene, polypropylene hydrophobic polymer, carboxymethyl cellulose (CMC), methyl cellulose (MC), and hydroxypropyl methyl cellulose ( HPMC), polyacrylate (for example, sodium polyacrylate (SPA)}, hydrophilic polymers, such as polyvinyl alkoxide (PVA), polyethylene oxide, rubber-based polymers, such as latex, etc. are mentioned.

Examples of the conductive substrate include a net-like, sponge-like, fibrous or melt-like metal porous body formed of a resin subjected to Nigel, stainless steel or nickel plating.

2) minus play (4)

This negative electrode 4 can be produced by adding a conductive material to the hydrogen storage alloy and stirring it together with a polymer binder and water to prepare a paste, which is then neutrally charged on a conductive substrate, dried and molded. .

The hydrogen storage alloy is not particularly limited and may be capable of storing hydrogen generated electrochemically in the electrolytic solution and easily discharging the hydrogen storage during discharge. As the hydrogen storage alloy, for example, LaNi ₅ , MmNi ₅ (Mm: mitsch metal), LmNi ₅ (Lm; lantern-rich mitsch metal), or a part of these Ni is Al, Mn, Co, Ti, Cu, Zn, The multi-element type substituted with elements, such as Zr, Cr, and B, or the thing of TiNi type, TiFe type, ZrNi type, MgNi type is mentioned. Among them, the general formula LmNixMnyAz (where A is at least one metal selected from Al and Co, and the atomic ratio (x, y, z) has a total value of 4.8 x + y + z 5.4) is preferably used. Since the negative electrode containing such a hydrogen storage alloy can suppress the differentiation accompanying the progress of the charge / discharge cycle, the charge / discharge cycle life of the secondary battery can be improved.

As said polymeric binder, the thing similar to what was used by the said positive electrode 2 is mentioned.

As the conductive material, for example, carbon black, activated carbon, or the like can be used.

Examples of the conductive substrate include two-dimensional substrates such as punched metal, expanded metal, nickel net, and the like, and three-dimensional substrates such as felt-like metal porous bodies and sponge-like metal substrates.

3) Alkaline Electrolyte

Examples of the alkaline electrolyte include potassium hydroxide (KOH) solution, lithium hydroxide (LiOH) solution, sodium hydroxide (NaOH) solution, a mixture of potassium hydroxide and lithium hydroxide, a mixture of potassium hydroxide and sodium hydroxide, lithium hydroxide and hydroxide hydroxide. The mixed liquid of sodium, the mixed liquid of potassium hydroxide, lithium hydroxide, and sodium hydroxide, etc. are mentioned.

Especially, it is preferable that the said electrolyte solution contains at least one of lithium hydroxide or sodium hydroxide.

The concentration of the alkaline electrolyte solution is about 5 or more. If the alkali regulation in the electrolyte is less than about 5, the conductivity of the electrolyte is lowered, so that the charge and discharge characteristics of high rate are lowered and the layer discharge cycle life is also lowered. In particular, an alkaline electrolyte having a concentration of about 7 to 8 grams is most suitable because of its high conductivity. In addition, an alkaline saturated solution may be used as the alkaline electrolyte. Therefore, the upper limit of the concentration of the alkaline electrolyte is the concentration of the saturated solution of the alkaline component contained in the electrolyte. The concentration of the saturated solution of alkali is changed depending on the type of alkali, which is a solute, and is about 9 to 10 grams.

When the electrolyte solution contains at least lithium hydroxide, the concentration of lithium hydroxide in the electrolyte solution is preferably in the range of 0.1N to 1.5N. If the concentration of lithium hydroxide in the electrolyte is outside the above range, there is a concern that the cycle characteristics of the nickel-hydrogen secondary battery and the self-discharge characteristics at high temperature storage may be reduced. More preferable concentration is in the range of 0.3N to 1.3N.

When the electrolyte contains at least sodium hydroxide, the concentration of sodium hydroxide in the electrolyte is preferably in the range of 0.5N to 6.0N. If the concentration of sodium hydroxide in the electrolyte is out of the above range, there is a fear that the cycle characteristics of the nickel-hydrogen secondary battery and the self-discharge characteristics during high temperature storage are deteriorated. More preferable concentration is in the range of 1.0N to 5.0N.

Alkaline electrolyte equivalent Xmeq / Ah per 1 Ah of battery capacity of the alkaline electrolyte solution can be obtained from the following formula (I) when the prescribed degree of the electrolyte is ZoN, the volume of the Hag electrolyte is Vml, and the battery capacity (nominal capacity) is CoAh. .

It is preferable that the alkali electrolyte equivalent (X) is in the range of 5 to 24 meq / Ah. This is for the following reason. When the alkali electrolyte equivalent amount (X) is less than 5 meq / Ah, there is a fear that the discharge capacity due to the decrease in the charge / discharge reaction efficiency may be reduced, which may shorten the cycle life. On the other hand, when the alkali electrolyte equivalent (X) exceeds 24 meq / Ah, even if the degree of regulation of the electrolyte is high, it is only up to polyconcentration, so that the amount of electrolyte is excessively high, which may affect battery performance such as safety. More preferable electrolyte equivalent (X) is the range of 6-21 meq / Ah, and still more preferable electrolyte equivalent (X) is the range of 7-19 meq / Ah.

4) Separator (3)

This separator 3 contains polyolefin synthetic resin fibers having an ion exchange group.

The separator may be a sheet-like article containing polyolefin-based synthetic resin fibers, and at least part of the fibers may have an ion exchange group. Although the whole polyolefin synthetic resin fiber contained in the said sheet-like thing may have an ion exchange group, one part of the fiber may have an ion exchange group. Such sheet-like articles include, for example, nonwoven fabrics containing polyolefin-based synthetic resin fibers, and at least a part of the fibers include ion-exchange groups, polyolefin-based synthetic resin fibers, and at least a portion of the fibrosis having an ion-exchange group. The composite sheet which laminated | stacked the multiple sheets of nonwoven fabrics, the composite sheet which laminated | stacked the multiple sheets of the said woven fabric, the composite sheet which laminated | stacked the multiple sheets of the said nonwoven fabric and the said woven fabric, etc. are mentioned.

In the composite sheet, the average diameters of the fibers included in the layers constituting the composite sheet may be the same as or different from each other.

The composite sheet includes polyolefin-based synthetic resin fibers, and at least a portion of the fibers includes an inner layer having an ion exchange group, and polyolefin-based synthetic resin fibers formed on both sides of the inner layer, and at least a portion of the fibers is an ion exchange group. It is good to have two surface layers which have a 3 layer structure in which the average diameter of the fiber contained in each said surface layer is large compared with the average diameter of the fiber contained in the said inner layer. The average diameters of the fibers contained in the two surface layers may be the same as or different from each other.

The separator including such a three-layered composite sheet can secure sufficient strength by the two surface layers and can hold a large amount of electrolyte solution by the inner layer, thereby simultaneously maintaining high strength and excellent electrolyte retention. Can satisfy. The nickel-hydrogen secondary battery provided with this separator can drastically improve cycle life.

In the three-layered composite sheet, it is preferable that the average diameter of the fibers of the inner layer is in the range of 0.5 µm to 5 µm, and the average diameter of the fibers in the surface layer is 7 µm to 20 µm. Do.

The reason for limiting the average diameter in the inner layer to the above range is for the following reason. If the average diameter is less than the pin type, the strength of the separator may decrease, and the separator may not be used as the separator. If the average diameter is more than 5 mu m, there is a fear that the electrolyte holding property of the inner layer is lowered. The more preferable average diameter in an inner layer is the range of 1 micrometer-3 micrometers.

The reason for limiting the average diameter in the surface layer to the above range is for the following reason. If the average diameter is less than 7 µm, it is difficult to maintain the mechanical strength of the separator and there is a fear that it cannot be used as a separator. If the average diameter is more than 20 mu m, there is a fear that the electrolyte holding property of the surface layer is lowered. The more preferable average diameter in a surface layer is the range of 8 micrometers-15 micrometers.

The polyolefin-based synthetic resin fiber is a composite fiber having a core sheath structure in which a polyolefin fiber different from the polyolefin fiber is coated on a core surface consisting of a single polyolefin fiber and a polyolefin fiber, and a composite fiber having a split structure in which different polyolefin fibers are circularly bonded to each other. And fibers made of a copolymer resin of polyolefin and butene. As said polyolefin, polyethylene, a polypropylene, etc. are mentioned, for example.

It is preferable that the average diameter of the polyolefin synthetic resin fiber contained in the said sheet-like thing shall be 0.5 micrometer-15 micrometers. In the separator, when the scale and thickness are kept constant and the average diameter is made smaller, the fibers are more closely intertwined with each other, so that the gaps between the fibers become smaller and the amount of the electrolyte maintained by the gaps increases, and the electrolyte retention of the separator is increased. However, when said average diameter is made small, the intensity | strength of a separator will fall. On the other hand, if the average diameter is increased, the strength is improved, but the intertwining of the fibers becomes sparse, so that the gap between the fibers increases, so that the amount of the electrolyte maintained by the gap is reduced, and the electrolyte retainability of the separator is reduced. If the gap is large, the coverage of the separator decreases. Therefore, when the average diameter is less than 0.5 mu m, the mechanical pin system of the separator becomes remarkable, and there is a fear that the assembly of the battery becomes difficult. On the other hand, when the average diameter exceeds 15 µm, there is a possibility that short between the positive and negative poles is caused by the decrease in the coverage. In particular, a separator having a sheet-like article containing polyolefin-based synthetic resin fibers having an average diameter of 0.8 to 12 µm is most suitable because of its moderate strength and ability to improve electrolyte retention in dense ones.

As said ion exchange group, a carboxyl group (COOH group), a sulfone group (SO3H group), a hydroxyl group (OH group), etc. are mentioned, for example. One type or two or more distillations in these ion exchange groups can be used for the said separator. The hydroxyl group preferably exhibits a strong acidity in the state imparted to the polyolefin-based synthetic resin fibers. Of these ion exchange groups, carboxyl groups are most suitable.

The ion exchange amount Y (meq / Ah) per battery capacity 1Ah of the separator can be measured by a titration method described below.

Titration

First, 0.5-1 g of a sample (for example, a polyolefin pin-based nonwoven fabric graft-copolymerized with acrylic acid) is attached to a large bottle of l00 ml polyethylene, and 100 m1 of 1N-HCl solution is added. After sitting, it is stored for 1 hour in a thermostat at 60 ° C. Subsequently, the sample is transferred to a beaker containing 200 m1 of ion-exchanged water, stirred with a glass rod, and the ion-exchanged water is exchanged and washed until the pH of the cleaning liquid is 6-7. Drain the sample, spread it over a stainless steel pad, and dry it for 1 hour with a dryer at 100 ° C. After cooling, the sample is weighed to 0.lmg and transferred into a wide bottle of l00m1 of polyethylene inlet, and 110g ± 0.0lg of these 0.0lN-KOH solutions are added. On the other hand, take 110g ± 0.01g of 0.0lN-KOH solution in a blank bottle of 100m1 polyethylene inlet as a blank sample. Subsequently, place the bottles with wide mouths in a thermostat at 60 ° C, shake gently every 30 minutes, and store for 2 hours. Lightly shake the wide mouth of each inlet, remove the samples, and allow them to cool to room temperature. Approximately 100 g of the test solution after cooling is weighed up to 0.01 g in a 200 m1 mechanical beaker and neutralized with 0.1 N-HC1 solution using phenolphthalein as an indicator. The blank test solution is also titrated in the same manner. By such titration, the potassium ion exchange amount (meq / g) per 1g of sample is calculated by the formula shown below.

Where I. E. C; Potassium ion exchange amount (meq / g),

T _l ; Amount of 0.lN-HC1 solution required for titration of sample solution (ml)

T ₂ ; Amount of 0.1 L-HC1 solution required for titration of the blank solution (ml),

S ₁ ; Weight of collected sample solution (g),

S ₂ ; Weight of the blank solution collected (g),

W ₁ ; Weight of the sample after drying (g),

E _l ; Amount (g) of 0.0lN-KOH solution added,

F; Factor of 0.1 N-HCl solution,

Indicates.

The amount of nominal potassium ion exchanged in the sample thus obtained is Yo (meq / g), the weight of the sample is W (g), and the sample is used as a separator. When it is set as (Ah), the ion exchange amount (potassium ion exchange amount) (Y) (meq / Ah) per battery capacity of 1Ah of the sample can be obtained from the following formula (II).

In addition, in the formula (II), the weight (Wg) is used instead of the scale amount (g / m ² ) because the weight of the separator is different for each separator due to unevenness when the scale amount and size (size) are constant. .

The ion-exchange amount (Y) (meq / Ah) per 1Ah of battery capacity of the separator is expressed by the formula (1) below when the alkali electrolyte equivalent per battery capacity of 1Ah of the alkaline electrolyte is 5 or more in concentration. To satisfy.

The reason why the ion exchange amount Y (meq / Ah) uses a separator that satisfies the formula (1) is as follows. The ion exchange amount (Y) (meq / Ah) per 1 Ah of battery capacity of the separator is represented by the following formula (2)

If it is smaller than the value obtained from the above, since the electrolyte holding property of the separator is lowered, the layer discharge cycle life is lowered. In the nickel-hydrogen secondary battery, swelling of the positive electrode and corrosion of the hydrogen storage alloy of the negative electrode occur along with the progress of the charge / discharge cycle, and the electrolyte solution is consumed. In order to compensate for the shortage of the amount of the electrolyte solution in the positive electrode and the negative electrode due to these reactions, an electrolyte solution is moved from the separator to the positive electrode and / or the negative electrode. The separator whose ion exchange amount (Y) is smaller than the value obtained from the above {0.409- (X / 55)} has a low electrolyte holding property, so that the electrolyte that moves to the positive electrode and the negative electrode with the progress of the charge / discharge cycle The ratio is high. For this reason, with the progress of a charge / discharge cycle, the amount of electrolyte solution in a said separator becomes remarkably small, the electrical conductivity of the separator falls and the charge / discharge cycle life falls.

In order to realize good charge / discharge cycle characteristics, the minimum required amount of ion exchange (Y) is reduced according to the above formula (2) as the alkali electrolyte solution amount (X) is increased.

In other words, good cycle characteristics can be ensured up to a range of ion exchange amount (Y) smaller than that of the secondary battery single pin system having a high electrolyte equivalent (X). It is assumed that this is caused by the following mechanism.

That is, when the ion exchange amount (Y) of the separator is small, the movement of the electrolyte to the positive and negative poles of the separator accompanying the progress of the charge / discharge cycle is more likely to be affected by the viscosity of the electrolyte than the amount of the ion exchanger in the separator. appear. In nickel-metal hydride batteries, there is a limit to the amount of alkaline electrolyte that can be accommodated in a container. When the battery capacity (nominal capacity) is constant, the higher the alkaline electrolyte equivalent (X) per 1 Ah of battery capacity, the more alkaline alkali is used. The concentration of the liquid tends to be high. Since the electrolyte solution having a high electrolyte equivalence (X) has a high concentration and has a high viscosity and a low mobility, it is possible to suppress the movement of the electrolyte solution in the separator to the positive electrode and the negative electrode as the charge and discharge cycle proceeds. For this reason, the nickel-hydrogen secondary battery provided with such an electrolyte solution can secure good cycle characteristics by using a separator having a smaller amount of ion exchanger than the case of using an electrolyte solution having a low electrolyte equivalent (X).

On the other hand, the divorce exchange amount (Y) (meq / Ah) per lAh of battery capacity of the separator is represented by the following formula (3)

If it becomes larger than the value obtained from the above, since the amount of distribution of the electrolyte solution to the positive electrode minus pole at the beginning of the charge and discharge cycle is insufficient, the charge and discharge cycle life is shortened. That is, since such a separator has more electrolyte retention than necessary, the amount of electrolyte of a positive electrode and a negative electrode decreases relatively. Since H ₂ O is required for charging and discharging the positive electrode, when the amount of the electrolyte is small, the charge and discharge reaction efficiency is lowered and the discharge capacity is lowered. In addition, when the electrolyte starts to be consumed due to the swelling of the positive electrode or the corrosion reaction of the hydrogen storage alloy of the negative electrode with the progress of the layer discharge cycle, the lack of the electrolyte of the positive electrode becomes more significant. As a result, the charge and discharge capacity is lowered at a relatively early time and the charge and discharge cycle life is reduced.

In addition, as the separator electrolyte solution (X) containing polyolefin-based synthetic resin fibers having an ion exchange group is increased, good cycle characteristics can be ensured up to a range of a larger ion exchange amount (Y). This permissible upper limit value changes according to the above expression (3). It is assumed that this is due to the following mechanism.

That is, when the ion exchange amount Y of the separator is constant, the affinity of the alkali metal ion and the water molecule increases as the electrolyte equivalent amount X (concentration of the electrolyte solution) increases compared with that of the ion exchanger and the group molecule. When the ion exchange amount (Y) is large, such a difference in affinity causes the amount of electrolyte that the separator can actually hold decreases with an increase in the electrolyte equivalent amount (X), thereby preventing the electrolyte from biasing the separator. . For this reason, in a nickel-hydrogen secondary battery equipped with a separator having a large ion exchange amount (Y), the higher the electrolyte equivalent (X) (the concentration of the electrolyte), the more positive the charge / discharge cycle will be. It is possible to set the distribution state of the electrolyte solution to the pole, the minus pole, and the separator to be most suitable.

In addition, the ion exchange amount (Y) (meq / Ah) per battery capacity of 1 Ah of the separator is represented by the following formula (4)

It is more preferable to satisfy.

It is preferable that the thickness of the separator be in the range of 0.15 mm to 0.3 mm.

Scale amount of the separator is preferably in the range of 30g / m ² ~70g / m ² and range. If the scale amount is less than 30 g / m ² , the strength of the separator 3 may be lowered. On the other hand, when the graduation amount exceeds 70 g / m ² , there is a fear that the battery capacity is lowered. More preferable graduation amount is the range of 40g / m <^2> -60g / m <^2> .

The said separator can be manufactured by the method of (a)-(c) shown below, for example.

(a) The sheet-like object containing polyolefin synthetic resin fiber is immersed in the solution containing the vinyl monomer which has an ion exchange group, and is attracted. A separator is produced by irradiating an energy beam to the sheet-like material by graft copolymerization of the vinyl monomer.

(b) A separator is prepared by irradiating an energy beam on a sheet-like article comprising polyolefin-based synthetic resin fibers and then immersing the sheet-like article in a solution containing a vinyl monomer having an ion-exchange group to graft copolymerize the vinyl monomer.

(c) A separator is prepared by immersing a sheet-like material containing polyolefin-based synthetic resin fibers in a solution containing a vinyl monomer having an ion-exchange group, and simultaneously irradiating an energy beam to the sheet-like material to graft copolymerize the vinyl monomer.

Examples of the sheet-like article including the polyolefin synthetic resin fibers include a woven fabric made of pin-based copper fibers made of polyolefin synthetic resin fibers, a composite sheet obtained by laminating a plurality of nonwoven fabrics, a composite sheet obtained by laminating a plurality of woven fabrics, the nonwoven fabric, and the like. The composite sheet etc. which laminated | stacked multiple sheets of the said woven fabrics are mentioned. The nonwoven fabric is produced by, for example, a dry method, a wet method, a span bond method, a melt blow method, or the like. Among these methods, the span bond method and the melt blown method are advantageous in terms of prevention of short between the plus and minus poles because a nonwoven fabric having a thin fiber diameter can be produced. Moreover, it is preferable that the light stabilizer is not contained in the said sheet-like thing. Such a sheet-like article can be produced, for example, from a polyolefin-based synthetic resin fiber without a light stabilizer.

Examples of the polyolefin synthetic resin fibers include those similar to those described above.

Examples of the vinyl monomers include acids, such as acrylic acid monomers, methacrylic acid monomers, monomers of acrylic acid or methacrylic esters, vinylpyridine monomers, vinylphyllidene monomers, styrene sulfonic acid monomers, and styrene monomers. And vinyl monomers having a functional group capable of reacting with a base to form a salt, or vinyl monomers having a functional group capable of being hydrolyzed to form a salt. Among the vinyl monomers, acrylate monomers are most suitable.

As the energy beam, ionizing radiation such as ultraviolet rays, electron beams, and X-rays can be used.

In the above methods (a) to (c), it is preferable to use a sheet-like article containing polyolefin-based synthetic resin fibers containing no light stabilizer as a sheet-like article when ultraviolet rays are employed as the energy beam. According to this method, it is possible to graft-copolymerize the vinyl monomer in a uniform and sufficient amount as compared with the case of irradiating the same amount of ultraviolet rays to the sheet-like article containing the light stabilizer, and also to improve the production efficiency. .

In addition, in FIG. 1 mentioned above, although it wound around the vortex shape through the separator 3 between the plus pole 2 and the minus pole 4, and stored in the bottomed cylindrical container 1, of the present invention, The nickel-hydrogen secondary battery is not limited to such a structure. For example, a rectangular nickel-metal hydride secondary battery may be constructed by storing a positive electrode and a negative electrode in a rectangular cylindrical container with a bottom, which is produced by alternately interposing a separator therebetween via a separator.

The related pin-type Nigel hydrogen secondary battery according to the present invention includes a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkali electrolyte solution. The separator is formed by treating the sheet-like material containing the polyolefin-based synthetic resin fiber having an ion exchange group with an alkaline aqueous solution having the same type and ability ratio as the alkaline electrolyte and forming the ion exchange group in the form of a salt.

Such a Nigel hydrogen secondary battery can be applied to a cylindrical nickel hydrogen secondary battery having the structure shown in FIG. In addition, the Nigel hydrogen secondary battery according to the present invention is not limited to a cylindrical shape, and for example, a laminate produced by alternately stacking a positive electrode and a negative electrode through a separator therebetween is housed in a bottomed rectangular cylindrical container. Applicable to rectangular nickel-hydrogen secondary battery of structure.

As the positive electrode and the negative electrode, the same ones as described above can be used.

(1) Alkaline Electrolyte

As the alkaline electrolyte, for example, an aqueous solution of sodium hydroxide (NaOH), an aqueous solution of lithium hydroxide (LiOH), an aqueous solution of potassium hydroxide (KOH), a mixed solution of NaOH and LiOH, a mixed solution of KOH and LiOH, a mixed solution of KOH, LiOH and NaOH Etc. can be used. Especially, it is preferable that the said electrolyte solution contains at least one of lithium hydroxide or sodium hydroxide.

When the electrolyte solution contains at least lithium hydroxide, the concentration of lithium hydroxide in the electrolyte solution is preferably in the range of 0.1N to 1.5N. If the concentration of lithium hydroxide in the electrolyte is out of the above range, there is a fear that the cycle characteristics of the nickel-hydrogen secondary battery decreases. More preferable range is 0.3N-1.3N.

When the electrolyte contains at least sodium hydroxide, the concentration of sodium hydroxide in the electrolyte is preferably in the range of 0.5N to 6.0N. If the concentration of sodium hydroxide in the electrolyte is out of the above range, there is a fear that the cycle characteristics of the nickel-hydrogen secondary battery decreases. More preferable concentration is in the range of 1.0N to 5.0N.

(2) separator

The separator is formed by treating the sheet-like material containing polyolefin-based synthetic resin fibers having an ion exchange group with an alkaline aqueous solution having the same type and concentration ratio as the alkali electrolyte solution, for example, by immersing the ion exchange group in the form of a salt.

Although the whole polyolefin synthetic resin fiber contained in the said sheet-like thing may have an ion exchange group, one part of the fiber may have an ion exchange group. Such sheet-like articles include, for example, nonwoven fabrics containing polyolefin-based synthetic resin fibers, at least a portion of which includes ion-exchange groups, polyolefin-based synthetic resin fibers, and at least a portion of the fibers having an ion-exchange group, The composite sheet which laminated | stacked the multiple sheets of the said nonwoven fabrics, the composite sheet which laminated | stacked the multiple sheets of the said woven fabric, the composite sheet which laminated | stacked the said nonwoven fabric and the said woven fabric in multiple sheets, etc. are mentioned. The separator composed of the composite sheet is compact and has high tensile strength.

In the composite sheet, the average diameters of the fibers included in the layers constituting the composite sheet may be the same as or different from each other.

The composite sheet includes polyolefin-based synthetic resin fibers, and at least a portion of the fibers includes an inner layer having an ion exchange group, and polyolefin-based synthetic resin fibers formed on both sides of the inner layer, and at least a portion of the fibers It is good to have two surface layers which have an exchanger, and to have a three-layer structure in which the average diameter of the fiber contained in each said surface layer is large compared with the average diameter of the fiber contained in the said inner layer. In addition, the average diameters of the fibers incorporated in the two surface layers may be the same as or different from each other.

The separator comprising the alkaline aqueous solution treatment on such a three-layered composite sheet can secure sufficient strength by the two surface layers and can hold a large amount of electrolyte by the inner layer. And excellent electrolyte retention can be satisfied at the same time. The nickel-hydrogen secondary battery provided with this separator can drastically improve cycle life.

In the three-layered composite sheet, the average diameter of the fibers in the inner layer is in the range of 0.5 µm to 5 µm, and the average diameter of the fibers in the surface layer is in the range of 7 µm to 20 µm. It is preferable. The more preferable average diameter in the said inner layer is the range of 1 micrometer-3 micrometers. Moreover, the more preferable average diameter in the said surface layer is the range of 81 micrometers-15 micrometers.

The polyolefin-based synthetic resin fibers may be a composite fiber having a sheath structure in which polyolefin fibers different from the polyolefin fibers are coated on a core surface consisting of polyolefin single fibers and polyolefin fibers, and a divided structure in which different polyolefin fibers are circularly bonded to each other. The composite fiber, the fiber which consists of copolymerization resin of polyolefin and butene, etc. are mentioned. As said polyolefin, polyethylene, a polypropylene, etc. are mentioned, for example.

The average diameter of all the fibers constituting the sheet-like article is preferably 0.1 to 15 mu m from the viewpoint of increasing the density and preventing the short between the positive electrode and the negative electrode.

As said ion exchanger, the cation exchanger which exchanges a cation silver is preferable. Such cation exchange As for neulmyeon carboxyl group (COOH group), a sulfone group (S ○ ₃ H group) include a hydroxyl group (OH group), and the like. One or two or more kinds of these cation exchangers can be used for plural chapters. The hydroxyl group preferably exhibits strong acidity in a state imparted to the polyolefin synthetic resin fiber. Of these ion exchange groups, carboxyl groups are most suitable.

A plurality of sheets are formed in which the ion exchanger is in the form of a salt by treating the sheet-like article having the ion exchanger with an alkaline aqueous solution having the same type and concentration ratio as the alkali electrolyte. The alkaline aqueous solution used in the above treatment is not particularly limited as long as the alkaline component contained therein is the same concentration ratio as that of the alkaline electrolyte solution. This is because the compounding ratio of alkali metal ions input to the separator does not change even if the compounding ratio of the alkaline component of the treating liquid is the same as that of the alkaline electrolyte. However, from the viewpoint of improving the workability, it is preferable that the concentration of the carboxyl group be as low as possible within the range in which salts of alkali metal ions can be formed rapidly. In addition, the compounding ratio of the alkali metal ion input to the separator in the said process does not necessarily correspond with the concentration ratio of the alkali metal ion of a process liquid. This is because the ease of ion exchange varies depending on the type of alkali metal ion. Since lithium ions in the alkali metal ions are easily ion-exchanged, the proportion of lithium ions input to the separator tends to be higher than that of the treatment liquid.

The ion exchange amount {meq / g (milli-equivalent per gramme)} of the separator is preferably 0.2 to 2.0 meq / g in terms of potassium ion exchange obtained by the titration method described above. When the ion exchange amount is less than 0.2 meq / g, there is a fear that the self-discharge characteristics of the separator under hydrophilicity and high temperature environment may be reduced. On the other hand, as the amount of ion exchange increases, the self-discharge characteristics when stored in a high temperature environment is improved, but when the amount of ion exchange exceeds 2.0 meq / g, the amount of the ion exchange groups increases so much that the volume of the separator increases and discharge / discharge cycles. As the pressure increases, the internal pressure increases, and the cycle life may decrease. More preferable ion exchange amount is 0.7-1.4 meq / g.

It is preferable that the thickness of the separator be in the range of 0.15 mm to 0.3 mm.

It is preferable to make the scale amount of the said separator into the range of 30g / m <^2> -70g / m <^2> .

If the scale amount is less than 30 g / m ² , the strength of the separator may be lowered. Moreover, when the said graduation amount exceeds 70 g / m <^2> , there exists a possibility that a battery capacity may fall. More preferable graduation amount is the range of 40g / m <^2> -60g / m <^2> .

The separator can be produced, for example, by the security of the following (A) to (C).

(A) A sheet containing a polyolefin-based synthetic resin fiber containing no light stabilizer is immersed in a solution containing a vinyl monomer having an ion exchange group, and then the sheet-like material is irradiated with and the vinyl monomer is graft-copolymerized. The separator is prepared by immersing it in an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte after washing with water, followed by washing with water and drying.

(B) graft co-polymerization of the vinyl monomer on the sheet-like article by immersing the sheet-like article in a solution containing a vinyl monomer having an ion-exchange group after irradiating and onto a sheet-like article comprising a polyolefin-based synthetic resin fiber containing no light stabilizer. Let's do it. The separator is prepared by immersing it in an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte after washing with water, followed by washing with water and drying.

(C) The vinyl monomer is graft-copolymerized on the sheet-like article by irradiating and onto a sheet-like article comprising a polyolefin-based synthetic resin fiber containing no light stabilizer immersed in a solution containing a vinyl monomer having an ion-exchange group. The separator is prepared by washing this in an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte after washing with water, followed by washing with water and drying.

The sheet-like article including the polyolefin-based synthetic resin fibers not containing the light stabilizer may be made of, for example, a polyolefin-based synthetic resin fiber without the light stabilizer. Such sheet-like articles include, for example, a nonwoven fabric made of a polyolefin-based synthetic resin fiber without an optical stabilizer, a woven fabric made of copper fibers, a composite sheet obtained by laminating a plurality of the nonwoven fabrics, a composite sheet obtained by laminating a plurality of woven fabrics, the nonwoven fabric, and the like. The composite sheet etc. which laminated | stacked multiple sheets of the said woven fabrics are mentioned. The nonwoven fabric is produced by, for example, a dry method, a wet method, a span bond method, a melt blow method, or the like. Since the method of span bond method and melt blow method as described above can produce a nonwoven fabric having a thin fiber diameter, it is advantageous in terms of prevention of short between the positive electrode and the negative electrode.

Examples of the polyolefin synthetic resin fibers include those similar to those described above.

Examples of the vinyl monomers include acids, such as acrylic acid monomers, methacrylic acid monomers, monomers of esters of acrylic acid and methacrylic acid, vinylpyridine monomers, vinylphyllidene monomers, styrene sulfonic acid monomers, and styrene monomers. And vinyl monomers having a functional group capable of reacting with a base to form a salt, or vinyl monomers having a functional group capable of being formed by hydrolysis. Acrylic monomers are most suitable for the vinyl monomer.

Also in the method of the above (A) to (C), the method shown in the above (A) is most suitable because the loss of carbon radicals generated by ultraviolet irradiation is small and the control of the graft copolymerization ratio is simple.

The nickel-hydrogen secondary battery according to the present invention includes a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the minus electrode, and an alkaline electrolyte solution. The separator is formed of a sheet-like material containing polyolefin-based synthetic resin fibers having an ion exchange group, and when the average diameter of all the fibers constituting the separator is X µm times, the amount of ion exchange groups in the separator is Ymeq / g. Satisfy the following formulas (5) and (6),

The alkali electrolyte is characterized in that it comprises at least one of lithium hydroxide or sodium hydroxide.

Such a nickel-hydrogen secondary battery can be applied to a cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. In addition, the nickel-hydrogen secondary battery according to the present invention is not limited to a cylindrical shape, and for example, a laminate produced by alternately overlapping a positive electrode and a negative electrode via a separator therebetween is housed in a bottomed rectangular cylindrical container. Applicable to rectangular nickel-hydrogen secondary battery of structure.

As the positive electrode and the negative electrode, the same ones as described above can be used.

(1) separator

This separator is formed from a sheet-like material containing polyolefin synthetic resin fibers having an ion exchange group. Moreover, when the average diameter of the whole and oil of the said separator was X micrometer, and the potassium ion exchange amount of the said separator was Ymeq / g, they satisfy | fill following formula (5) and (6).

As said sheet-like thing, the nonwoven fabric containing the polyolefin type synthetic resin fiber which has the said ion exchange group, the woven fabric containing copper fiber, or the composite sheet frame compounded with these nonwoven fabrics and woven fabric are mentioned, for example.

The sheet-like article may be formed of only polyolefin synthetic resin fibers having ion exchange groups, but may include polyolefin synthetic resin fibers without ion exchange groups.

As polyolefin synthetic resin fibers, a composite fiber having a core sheath structure coated with polyolefin fibers different from the polyolefin fibers on a core surface consisting of poly, mono fibers and polyolefin fibers, and a composite fiber having a split structure in which different polyolefin fibers are circularly bonded to each other. And fibers made of a copolymer resin of polyolefin and butene. As said polyolefin, polyethyl lian, polypropyl, etc. are mentioned, for example.

When the sheet-like article is formed of the composite sheet, the average diameters of the polyolefin-based synthetic resin fibers of the layers constituting the composite sheet may be the same as or different from each other.

The sheet-like article is composed of an inner layer containing polyolefin synthetic resin fibers having ion exchange groups and two surface layers formed on both sides of the inner layer and containing polyolefin synthetic resin fibers having ion exchange groups. The average diameter of all the fibers constituting the cotton layer may be a composite sheet having a three-layer structure which is larger than the average diameter of all the fibers constituting the inner layer. Such a three-layered sheet-like article and a separator that satisfies the formulas (5) and (6) are high because the surface layer can hold a large amount of the electrolyte solution while ensuring sufficient strength. It can satisfy both strength and excellent electrolyte maintainability. The nickel-hydrogen secondary battery provided with this separator and the alkali electrolyte of the above-mentioned specific composition can significantly improve the self-discharge characteristic at the time of high temperature storage.

In the three-layered sheet-like article, the average diameter of all the fibers constituting the inner layer is in the range of 0.5 μm to 5 μm, and the average diameter of all the fibers constituting the surface layers is 7 μm to 20 μm. It is preferable to set it as the range of. The surface layers may be the same as or different from each other in average diameter.

The reason for limiting the average diameter in the inner layer to the above range is for the following reason. If the average diameter is less than 0.5 mu m, there is a fear that the strength of the separator decreases and that the separator cannot be used as a separator. Moreover, when the said average diameter exceeds 5 micrometers, there exists a possibility that the electrolyte holding property of a separator may fall. The more preferable average diameter in an inner layer is the range of 1 micrometer-3 micrometers.

The reason for limiting the average diameter in the surface layer to the above range is for the following reason. If the average diameter is less than 7 µm, it is difficult to maintain the mechanical strength of the separator and there is a fear that it cannot be used as a separator. If the average diameter exceeds 20 µm, there is a fear that the electrolyte holding property of the separator is lowered. The more preferable average diameter in a surface layer is the range of 8 micrometers-l5 micrometers.

Examples of the ion-exchange group, for example, and the like COOH groups, SO ₃ H group, OH group. The OH group preferably exhibits strong acidity in a state imparted to the polyolefin synthetic resin fiber. COOH groups are also most suitable for the ion exchange vapor.

The ion exchange group of the polyolefin-based synthetic resin fibers can be formed by, for example, graft copolymerization of vinyl monomer having ion exchange capacity.

Examples of the vinyl monomers include acids, such as acrylic acid monomers, methacrylic acid monomers, monomers of esters of acrylic acid and methacrylic acid, vinylpyridine monomers, vinylphyllidene monomers, styrene sulfonic acid monomers, and styrene monomers. And vinyl monomers having a functional group capable of reacting with a base to form a salt, or vinyl monomers having a functional group capable of being hydrolyzed to form a salt. Among the vinyl monomers, acrylic acid monomers are most suitable.

When the separator has an ion exchange amount representing the ion exchange group holding amount as Ymeq / g (milli-equivalent per gramme) and an average diameter of all the fibers constituting the separator as X µm, they are represented by the following formula (5) And (6).

The ion exchange amount Y (meq / g) of the separator can be determined by the titration method described above.

The average diameter (X) of all the fibers constituting the separator is 1 to 20 µm. In the separator, when the average diameter (X) is reduced in a range of scales and thicknesses, the fibers are more closely intertwined with each other, so that the gaps between the fibers become smaller and the electrolyte holding force of the gaps is increased and the electrolyte retention is improved. However, when the said average diameter X is made small, the intensity | strength of a separator will fall. On the other hand, when the average diameter (X) is increased by making the scale amount and thickness constant, the strength is improved, but since the entanglement between the fibers becomes sparse, the gap between the fibers becomes large, resulting in a decrease in the electrolyte holding force of the gap. do. If the gap is large, the coverage of the separator decreases. Therefore, when the average diameter X is less than 1 µm, the mechanical strength of the separator becomes remarkable, and there is a fear that the assembly of the battery becomes difficult. On the other hand, when the said average diameter exceeds 20 micrometers, the short between the plus and minus poles by the fall of a coverage may be frequent. More preferable average diameter (X) is 3-15 micrometers.

As described above, when the amount and thickness of the separator are constant, as the average diameter (X) increases, the gap between fibers increases, so that the electrolyte holding force of the gap is lowered and electrolyte retention is lowered. Therefore, in order to maintain a sufficient amount of electrolyte in the separator and improve the self-discharge characteristics at the time of high temperature storage, the amount of ion exchange groups in the separator is increased along with the increase in the average diameter (X), thereby increasing the hydrophilicity of the fiber itself, and the electrolyte even in large gaps. It needs to be in a range that can be maintained well. That is, in order to improve the self-discharge characteristic at the time of high temperature storage, the minimum required amount of potassium ion exchange (Y) needs to be increased in accordance with the formula (0.05X + 0.05) when the average diameter (X) is increased. When the amount of potassium ion exchange (Y) of the separator is less than the amount of potassium ion exchange that satisfies the formula (0.05X + 0.05), the electrolyte holding property of the separator is deteriorated, and the self-discharge characteristic at high temperature storage deteriorates. On the other hand, when the ion exchange amount (Y) exceeds 2.0 meq / g, the ion exchange capacity of the separator is increased, and the alkali metal ions in the electrolyte are immobilized on the separator. Therefore, the nickel-hydrogen secondary battery equipped with this separator has a high operating voltage at high current discharge. Lowers. As for the said ion exchange amount (Y), it is more preferable to satisfy following formula (7).

It is preferable that the thickness of the separator be in the range of 0.15 mm to 0.3 mm.

It is preferable to make the scale amount of the said separator into the range of 30g / m <^2> -70g / m <^2> . If the scale amount is less than 30 g / m ² , the strength of the separator 3 may be lowered. On the other hand, when the graduation amount exceeds 70 g / m ² , there is a fear that the battery capacity is lowered. More preferable graduation amount is the range of 40g / m <^2> -60g / m <^2> .

The said separator can be manufactured by the method of (a)-(c) shown below, for example.

(a) A sheet-like material containing polyolefin-based synthetic resin fibers having an average diameter of 1 to 20 µm is immersed in a solution containing a vinyl monomer having an ion-exchange group, and pulled up, followed by irradiation of energy beams on the sheet-like material to graft the vinyl monomer. Copolymerize. By such a method, a separator formed of a sheet-like material containing polyolefin synthetic resin fibers having an ion exchange group and satisfying the above formulas (1) and (2) is produced.

(b) After irradiating an energy beam to a sheet-like article containing polyolefin-based synthetic resin fibers having an average diameter of 1 to 20 Mm, the sheet-like article is immersed in a solution containing a vinyl monomer having an ion-exchange group to graft copolymerize the vinyl monomer. By such a method, a separator formed of a sheet-like material containing polyolefin synthetic resin fibers having an ion exchange group and satisfying the above formulas (1) and (2) is produced.

(c) immersing a sheet-like material containing a polyolefin-synthetic resin fiber having an average diameter of 1 to 20 µm in a solution containing a vinyl monomer having an ion-exchange group, and irradiating an energy beam to the sheet-like material to graft copolymerization of the vinyl monomer. Let's do it. By such a method, a separator formed of a sheet-like material containing polyolefin synthetic resin fibers having an ion exchange group and satisfying the above formulas (1) and (2) is produced.

Examples of the sheet-like article containing the polyolefin-based synthetic resin fibers having an average diameter of 1 to 20 µm include a nonwoven fabric made of polyolefin synthetic resin fibers, a woven fabric made of copper fibers, or a composite sheet composited with these nonwoven fabrics and woven fabrics. The nonwoven fabric is produced by, for example, a dry method, a wet method, a span bond method, a melt blow method, or the like. Among these methods, the span bond method and the melt blow method are advantageous in terms of prevention of short between the positive electrode and the negative electrode because a nonwoven fabric having a thin fiber diameter can be produced. Moreover, it is preferable that the light stabilizer is not contained in the said sheet-like thing. Such a sheet-like article can be produced, for example, from a polyolefin-based synthetic resin fiber without a light stabilizer.

As the energy beam, ionizing radiation such as ultraviolet rays, electron beams, and X-rays is employed.

In the above methods (a) to (c), it is preferable to use a sheet-like article containing polyolefin-based synthetic resin fibers containing no light stabilizer as a sheet-like article when ultraviolet rays are employed as the energy beam. According to such a method, it becomes possible to graft-copolymerize the vinyl monomer of a uniform amount and the amount of a product, compared with the case of irradiating the same amount of ultraviolet-ray to the sheet-like thing containing a light stabilizer, and also to improve production efficiency.

The separator may have an ion exchange group distribution in which the first surface is hydrophilic and the second surface opposite to the first surface has a hydrophilic portion and a hydrophobic portion. Such a separator is arrange | positioned so that the said 2nd surface may be located in the said minus pole side between the said plus pole and the minus pole. The hydrophilic portion is a region where an ion exchange group exists on the surface of the separator, and the hydrophobic portion is a region where no ion exchange group exists on the surface of the separator.

The hydrophobic part of the separator is partially filmed by, for example, embossing a sheet-like object. It can form by performing the process which the graft copolymerization of the vinyl monomer which has an ion exchange group is inhibited. The embossing is arbitrary, such as a circle | round | yen and square shape, a stripe shape, and the like. The hydrophobic portion of the separator is also formed by joining the nonwoven fabric, woven fabric or composite sheet with a woven fabric of polyolefin diameter resin fibers having a large fiber diameter.

Preferably, the second surface of the separator has an area ratio of 2 to 25% of the minority portion. If the area ratio of the hydrophobic portion is less than 2%, there is a fear that the effect of suppressing the increase in the internal pressure during overcharging by providing the hydrophobic portion may not be seen. On the other hand, if the area ratio of the minority portion exceeds 25%, the secondary battery provided with this separator may have a low operating voltage during high current discharge. The area ratio of the more preferable hydrophobic part is 8-20%.

The said 1st surface of the said separator may exist with 10% or less of hydrophobic parts in area ratio. In the first surface, when the hydrophobic portion is present, the area ratio needs to be smaller than the area ratio of the hydrophobic portion on the second surface. Moreover, the ion exchange group may exist in the whole surface of the said 1st surface of the said separator. This type of separator is disposed between the paste type positive electrode and the negative electrode such that the second surface is positioned on the negative electrode side, that is, the first surface is on the positive electrode side, so that the separator surface on the positive electrode side (the first surface is smaller than the negative electrode side). ), A large amount of alkaline electrolyte can be maintained. As a result, since an electrolyte solution film exists on the positive electrode surface, the electrolyte solution film does not allow hydrogen gas generated from the negative electrode to pass through the separator to reach the positive electrode during high temperature storage of the nickel-hydrogen secondary battery. It can greatly improve the self-discharge characteristics at high temperature storage.

It is formed from a sheet-like material containing polyolefin-based synthetic resin fibers having an ion exchange group, and the first side shows hydrophilicity, and the second side has a hydrophilic part and a hydrophobic part, and satisfies the above formulas (5) and (6). The separator may be embossed on a first surface of a sheet-like article made of polyolefin-based synthetic resin fibers having an average diameter of 1 to 20 µm to form an embossed surface, and the sheet-like article may be ion-exchanged. Immersing the solution in a solution containing a vinyl monomer, and adhering the solution to both surfaces of the sheet-like material for removing the filmed portion of the second surface opposite to the first surface, and irradiating an energy beam to the sheet-like material. Can be produced by a method comprising graft copolymerization of the vinyl monomers on the side of the solution.

Specifically, it can manufacture by the method demonstrated to following (1), for example.

(1) First, as shown in FIGS. 2 to 4, both surfaces of the sheet-like article (for example, nonwoven fabric) 21 made of polyolefin-based synthetic resin fibers having an average diameter of 1 to 20 µm (first surface 22, Embossing is performed from the 1st surface 22 side of the 2nd surface 23). By this embossing, a plurality of circular recesses 24 are formed in the sheet-like article, and a portion (film portion) 25 formed into a film on the bottom surface (emboss surface) of the recesses 24. Is formed. At the time of isochronous, a part of the second surface 23 of the sheet-like object 21 corresponding to the recessed portion 24 also becomes a filmed surface.

Next, the sheet-like article is immersed in a solution containing a vinyl monomer having ion exchange ability and attracted. At this time, since the film portion 25 is formed on the bottom surface of the concave portion 24 as shown in FIG. 3, the sheet-shaped fin 21 has the solution attached to both surfaces of the film portion 25. FIG. And the solution is attached to an area other than the two sides, i.e., the nonwoven fabric portion. However, in the surface 22 of the recessed part 24 side of the said film part 25, since the said solution is filled in the said recessed part 24, the said solution contacted substantially the surface of the said recessed part 24 side. Will be.

Next, the sheet-like material is irradiated with an energy beam to graf the copolymer to the vinyl monomer on the surface of the solution. By such a process, the said vinyl monomer is graft-copolymerized and hydrophilized in the whole 1st surface of the sheet-like object of the said recessed part side. The solution is not attached to the film portion of the bottom of the concave portion of the second surface of the sheet-like article, and the solution is attached to a region of the second surface other than this. As a result, in the 2nd surface of the said sheet-like thing, the area | region of the film part of the bottom part of the said recessed part becomes a hydrophobic part, and the other area | region becomes a hydrophilic part.

Therefore, the above-described process comprises a sheet-like article comprising polyolefin-based synthetic resin fibers having an ion-exchange group, and the first side of the sheet-like article exhibits hydrophilicity, and the second side opposite to the first side has a hydrophilic section and a hydrophobic section. And a separator that satisfies the above relational expression is produced.

The embossing for the first surface side of the sheet-like article is, for example, a first roll having a smooth surface disposed opposite to each other and a second roll having a plurality of pinpoint protrusions formed on the surface thereof. The polyolefin of the said sheet-like thing is prepared, and these rolls are heated, for example to 120 degreeC-180 degreeC, and the said sheet-like thing is supplied between these rolls, and between the said 1st roll surface and the some processus | protrusion of the said 2nd roll. It is made by pressurizing and heat-sealing synthetic resin fibers. In addition to the pin point, the shape of the projection formed on the surface of the second roll may be, for example, a square in the shape of the tip end face and a diamond in the shape of the tip end face.

As the energy beam, the same one as described above is used.

Moreover, the said separator can be manufactured by the method shown to following (2).

(2) First, a nonwoven fabric made of polyolefin synthetic resin fibers is formed of a polyolefin synthetic resin fiber having a large diameter, and a woven fabric having a large gap is attached to form a sheet. In this sheet-like article, the non-attachment surface of the said woven fabric is a 1st surface, and the adhesion surface of the said woven fabric is a 2nd surface. Subsequently, the sheet-like article is immersed in a solution containing a vinyl monomer having an ion exchange group and attracted. At this time, the solution is not attached to the woven fabric attached to the second surface of the sheet-like article, and the solution is attached to the nonwoven fabric positioned on the gap between the woven fabric and the nonwoven fabric displayed on the first surface. Subsequently, when the sheet-like article is irradiated with an energy beam such as the above-mentioned ultraviolet ray, the vinyl monomer is graft-copolymerized on the surface of the solution. In such a process, the solution is ignited by graft copolymerization of the vinyl monomer on the first surface of the sheet-like article attached to the entire surface. On the other hand, in the second surface of the sheet-like article with the woven fabric, the solution is attached to the nonwoven fabric positioned in the gap between the woven fabrics, so that the graft co-polymerization of the vinyl monomer is performed by only the portion thereof. That is, in the 2nd surface of the said sheet-like thing, the area | region of the said woven fabric becomes a hydrophobic part and the other area | region becomes a hydrophilic part.

Therefore, by the above process, it is formed from the sheet-like thing containing a polyolefin synthetic resin fiber, and has a 1st surface of a hydrophilic part, a 2nd surface which has a hydrophilic part, and a hydrophobic part, Formula (1) and Formula (2) A separator that satisfies is produced.

In the separator production method of (1) to (2) above, in the case where ultraviolet rays are employed as the energy beam, it is preferable to use a sheet-like article containing polyolefin-based synthetic resin fibers containing no light stabilizer as the sheet-like article. According to such a method, compared with the case of irradiating the same amount of self-directed line to the sheet-like object containing a light stabilizer, it is possible to graft-copolymerize polyolefin and a sufficient amount of said vinyl monomer, and also to improve production efficiency. .

2) Alkaline Electrolyte

The electrolyte solution includes at least one of lithium hydroxide (LiOH) or sodium hydroxide (NaOH). Such electrolytes include, for example, aqueous lithium hydroxide solution, aqueous sodium hydroxide solution, a mixture of potassium hydroxide (KOH) and lithium hydroxide, a mixed solution of potassium hydroxide and sodium hydroxide, a mixed solution of potassium hydroxide, lithium hydroxide and sodium hydroxide, lithium hydroxide and The mixed liquid of sodium hydroxide is mentioned.

When the electrolyte solution contains at least lithium hydroxide, the concentration of lithium hydroxide in the electrolyte solution is preferably in the range of 0.1N to 1.5N. If the lithium hydroxide concentration in the electrolyte is out of the above range, there is a fear that the self-discharge characteristics during the polyolecular storage of the nickel-hydrogen secondary battery decrease. More preferable concentration is in the range of 0.3N to 1.3N.

When the electrolyte contains at least sodium hydroxide, the concentration of sodium hydroxide in the electrolyte is preferably in the range of 0.5N to 6.0N. If the ability of sodium hydroxide in the electrolyte is outside the above range, there is a fear that the self-discharge characteristics during high temperature storage of the nickel-hydrogen secondary battery decreases. More preferable concentration is in the range of 1.0N to 5.0N.

The nickel-hydrogen secondary battery according to the present invention includes nickel hydroxide as a polyolee plus electrode, a negative electrode containing a hydrogen storage alloy, a separator, and an alkaline electrolyte, and the separator includes a sheet containing water-repellent synthetic resin fibers; The sheet comprising hydrophilic synthetic resin fibers is integrated, and the separator is disposed between the positive electrode and the negative electrode such that the sheet containing the water-repellent synthetic resin fiber is positioned on the negative electrode side. It is characterized by.

In such a nickel-hydrogen secondary battery, for example, the separator is interposed between the positive electrode and the negative electrode such that a sheet containing the water-repellent synthetic resin fiber is positioned on the negative electrode side, and the electrode is wound in a spiral shape. A group can be produced, and this electrode group and alkali electrolyte solution can be manufactured by storing in a bottomed cylindrical pot and sealing. In addition, the nickel-hydrogen secondary battery according to the present invention is not limited to the above-mentioned cylindrical shape, for example, a separator is provided between a positive electrode and a negative electrode so that a sheet containing water-repellent synthetic resin fibers is positioned on the negative electrode side. Polyolefins may be produced by alternating stacking, and the laminate and the alkaline electrolyte may be stored in a rectangular cylindrical container with a bottom to constitute a square nickel-hydrogen secondary battery.

As the positive electrode and the negative electrode, the same ones as described above can be used.

(1) separator

The separator is formed by integrating a sheet containing water repellent synthetic resin fibers and a sheet containing synthetic resin fibers having hydrophilic properties, and the separator includes the water repellent synthetic resin fibers between the positive electrode and the negative electrode. The sheet is disposed so as to be located on the negative electrode side.

The separator may be a combination of one sheet containing the water repellent synthetic resin fibers and one sheet containing the hydrophilic synthetic resin fibers, but a sheet containing the water repellent synthetic resin fibers, or the synthetic resin having the hydrophilic property. Either one of the sheets containing the fibers may be formed in plural sheets, or a plurality of sheets containing the water-repellent synthetic resin fibers and a plurality of sheets containing the hydrophilic synthetic resin fibers may be integrated. good. Integrating these sheets can be performed by thermocompression bonding, for example.

As a sheet | seat containing the said water-repellent synthetic resin fiber, the nonwoven fabric which consists of a polytetrafluoro ylene fiber, the sheet | seat which consists of polyolefin synthetic resin fibers, etc. are mentioned, for example. In particular, the sheet made of the polyolefin synthetic resin fibers is most suitable because it can be easily produced and cheap.

In the sheet containing the water-repellent synthetic resin fibers, the sheet formed of polytetrafluoroerylene fibers is allowed to include inorganic fibers such as glass fibers, for example. Such a nonwoven fabric can improve the mechanical strength.

The nonwoven fabric which consists of said polytetrafluoroethylene fiber can be produced, for example by the method shown next. A polytetrafluoroethylene fiber containing either or both of stretched or unstretched is produced using a matrix composed of a dispersion of polytetrafluoroethylene and a binder. A sheet-like product is produced from the resin fibers by wet papermaking, and sintering is performed at a temperature equal to or higher than the melting point of polytetrafluoroethylene, thereby performing interlaced fiber fusion, and thermally decomposing the binder to remove poly. The nonwoven fabric which consists of tetrafluoroethylene fiber is produced.

In the sheet including the water-repellent synthetic resin fibers, when the polyolefin-based synthetic resin fibers are formed, the polyolefin-based synthetic resin fibers include polyolefin fibers and polyolefin fibers coated with polyolefin fibers different from the polyolefin fibers on a core surface consisting of polyolefin fibers. And composite fibers of a split structure in which different polyolefin fibers are circularly bonded to each other. As said polyolefin, polyethylene, a polypropylene, etc. are mentioned, for example.

As the sheet made of the polyolefin synthetic resin fibers, for example, a nonwoven fabric made of polyolefin synthetic resin fibers, a woven fabric made of copper fibers, or a composite sheet composited with these nonwoven fabrics and woven fabrics can be used. The nonwoven fabric is produced by, for example, a dry method, a wet method, a span bond method, a melt blow method, or the like.

It is preferable that the graduation amount of the sheet | seat containing the said water-repellent synthetic resin fiber shall be in the range of 5 g / m <^2> -30g / m <^2> . This is for the following reason. If the graduation amount is less than 5 g / m ^2, there is a concern that the gas absorption on the negative electrode surface is lowered. On the other hand, when the graduation amount exceeds 30 g / m ² , it is difficult to maintain the alkaline electrolyte in the sheet.

As the sheet containing the synthetic resin fibers having hydrophilicity, a sheet made of polyamide synthetic resin fibers (e.g. nylon 6, 6 fibers, etc.), or a sheet made of polyolefin synthetic resin fibers, resin fiber treated, poly The nonwoven fabric which consists of tetrafluoroethylene fiber, and the like which were hydrophilic-treated were mentioned. Particularly, the hydrophilic treatment of the polyolefin-based synthetic resin fiber sheet has a high amount of hydrophilic functional groups and high electrolytic solution retention and excellent oxidation resistance, thereby preventing self discharge during high temperature storage of the secondary battery. Most suitable. Examples of the polyolefin synthetic resin fibers include those similar to those described above. Moreover, the same thing as mentioned above is mentioned as said polyolefin synthetic resin fiber sheet. In the method for producing the polyolefin synthetic resin fiber nonwoven fabric, the span bond method and the melt blow method are advantageous in terms of prevention of short between the positive electrode and the negative electrode because the nonwoven fabric having a thin fiber diameter can be produced. In particular, the nonwoven fabric is preferably made of polyolefin-based synthetic resin fibers having a fiber diameter of 0.1 to 15 µm from the viewpoint of preventing short between the positive electrode and the negative electrode.

As a hydrophilic treatment performed on the nonwoven fabric which consists of said polytetrafluoroethylene fiber, a plasma process is mentioned, for example.

Examples of the hydrophilic treatment performed on the polyolefin synthetic resin fiber sheet include plasma treatment, sulfonation treatment and graft copolymerization of vinyl monomers having ion exchange groups. In particular, the graft copolymerization can be carried out without damaging the polyolefin synthetic resin fibers, and is most suitable because the vinyl monomer having an ion exchange group imparted to the fibers has high hydrophilicity.

When plasma treatment is performed on the nonwoven fabric made of the polytetrafluoroethylene fiber or the polyolefin synthetic resin fiber sheet, the nonwoven fabric or the sheet is subjected to oxidation treatment, thereby providing hydrophilicity to the nonwoven fabric or the sheet.

Graft copolymerization of vinyl monomers having an ion exchange group to the polyolefin synthetic resin fiber sheet can be carried out by, for example, the following method.

(1) The vinyl monomer is graft-copolymerized by irradiating an energy beam to the sheet and immersing the sheet in an aqueous solution containing a vinyl monomer having an ion exchange group.

(2) The sheet is immersed in a solution containing a vinyl monomer having an ion exchanger and attracted to it. An energy beam is irradiated to this sheet to graft copolymerize the vinyl monomer.

As the energy beam, ionizing radiation such as ultraviolet rays, electron beams, and X-rays is used.

In the methods (1) and (2), radicals generated when the sheet is irradiated with an energy beam are lost after a predetermined time has elapsed. The method of (2) is most suitable because the loss of radicals is small.

The vinyl monomer may form a salt by reacting with a direct acid or a base such as acrylic acid, methacrylic acid, the acrylic acid or the ester of the vinyl, vinylpyridine, vinylphyllide, styrenesulfonic acid, styrene, or the like. And a functional group capable of forming a salt by hydrolysis after graft copolymerization. Acrylic acid is also most suitable as the vinyl monomer.

In the method for manufacturing the separator described in the above (1) and (2), in the case of employing ultraviolet rays as the energy beam, it is preferable to use a sheet containing polyolefin-based synthetic resin fibers containing no light stabilizer as a sheet. According to the method, it is possible to graft-copolymerize the vinyl monomer in a uniform and sufficient amount in a uniform and sufficient amount as compared with the case of irradiating the sheet containing the light stabilizer with the same amount of ultraviolet rays, and also to improve the production efficiency. In addition, the sheet containing the polyolefin-based synthetic resin fibers containing no light stabilizer can be made of, for example, a polyolefin-based synthetic resin fiber without the light stabilizer.

The graft copolymerization ratio of the vinyl monomer to the separator is 0.2 to 2.0 meq / g based on the ion exchange amount determined by the above titration method, and the graft copolymerization ratio to the separator is less than 0.2 meq / g of vinyl. There exists a possibility that this may fall and the liquid retention property of the said separator may fall. On the other hand, when the ion exchange amount exceeds 2.0 meq / g, there is a fear that the operating voltage when the secondary battery discharges a large current is reduced.

The thickness of the separator should be in the range of 0.15 mm to 0.3 mm.

It is preferable to make the scale amount of the said separator into the range of 30g / m <^2> -70g / m <^2> . If the scale amount is less than 30 g / m ² , the strength of the separator may be lowered. On the other hand, when the graduation amount exceeds 70 g / m ² , there is a fear that the battery capacity is lowered. More preferable graduation amount is the range of 40g / m <^2> -60g / m <^2> .

(2) Alkaline Electrolyte

Examples of the alkaline electrolyte include an aqueous solution of sodium hydroxide (NaOH), an aqueous solution of lithium hydroxide (LiOH), an aqueous solution of potassium hydroxide (KOH), a mixed solution of NaOH and LiOH, a mixed solution of KOH and LiOH, a mixed solution of KOH, LiOH, and NaOH Etc. can be used. Also in that case, it is preferable that the said electrolyte solution contains at least one of lithium hydroxide or sodium hydroxide.

When the electrolyte solution contains at least ritum hydroxide, the concentration of the lithium hydroxide in the electrolyte is preferably in the range of 0.1N to 1.5N. If the concentration of lithium hydroxide in the electrolyte is out of the above range, there is a fear that the cycle characteristics of the Nigel hydrogen secondary battery decrease. More preferable concentration is in the range of 0.3N to 1.3N.

When the electrolyte contains at least sodium hydroxide, the concentration of sodium hydroxide in the electrolyte is preferably in the range of 0.5N to 6.0N. If the concentration of sodium hydroxide in the electrolyte is out of the above range, there is a fear that the cycle characteristics of the nickel-hydrogen secondary battery decreases. More preferable concentration is in the range of 1.0N to 5.0N.

As described above, the nickel-hydrogen secondary battery according to the present invention comprises a separator containing a polyolefin-based synthetic resin fiber having an ion exchange group, an alkali electrolyte having a concentration of 5 or more, and an alkali electrolyte equivalent per battery capacity of the electrolyte. When X (meq / Ah) is set and the ion exchange amount per 1Ah of the battery capacity of the separator is Y (meq / Ah), the ion exchange amount (Y) is represented by the following formula (1)

To satisfy. In such a secondary battery, since the ion exchange amount per battery capacity of 1Ah of the separator is set in consideration of the alkali electrolyte solution equivalent weight per battery capacity, the charge and discharge cycle life can be improved.

That is, in the nickel-hydrogen secondary battery, since the amount of alkaline electrolyte that can be contained in the container is limited, the distribution state of the alkaline electrolyte to the positive electrode, the negative electrode, and the separator greatly affects the cycle life characteristics. In order to make this distribution suitable, the relationship between the alkaline electrolyte equivalent amount per battery capacity of 1 Ah of the said electrolyte solution, and the ion exchange amount per battery capacity of 1 Ah of a separator is important. The nickel-hydrogen secondary battery having a separator that satisfies the above formula (1) has the most suitable electrolyte distribution state for the plug electrode, the negative electrode, and the separator at the beginning of the OH cycle, and is accompanied by the progress of the charge / discharge cycle. Charge / discharge cycle life can be maintained because the most suitable distribution can be maintained over a long period of time by preventing or avoiding movement of the electrolyte in the separator to the positive and / or negative electrodes.

Can be improved.

Further, the ion exchange amount (Y) of the separator is represented by the following formula (4)

By setting it as the value within the range shown by, the OH whole cycle life can be improved remarkably.

The nickel-hydrogen secondary battery according to the present invention includes a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator sandwiched between the positive electrode and the negative electrode, and an alkaline electrolyte solution. The separator comprises the ion exchange group in the form of a salt by treating a sheet-like material containing polyolefin-based synthetic resin fibers having an ion exchange group with an alkaline aqueous solution having the same type and ability ratio as the alkaline electrolyte. Such a secondary battery can realize high cycle life because the type and concentration ratio of the alkaline electrolyte do not vary when the electrode group and the alkaline electrolyte formed of the positive electrode, the negative electrode, and the separator are accommodated in the container.

That is, an alkaline aqueous solution (e.g., 0.5 standard) having the same type as the alkaline electrolyte (for example, 7% potassium hydroxide and 1% lithium hydroxide) is used as a sheet-like material containing polyolefin-based synthetic resin fibers having ion exchange groups. It consists of potassium hydroxide and 0.5% lithium hydroxide), and the molar ratio (K +: Li +) of the cation of the ion exchanger in the form of a salt by the alkaline aqueous solution is obtained when the sheet-like material is treated with the alkali electrolyte. It is different from the molar ratio of cation input to it. When the alkaline aqueous solution-treated sheet-like material is incorporated into the secondary battery as a separator, the cation in the alkaline electrolyte and the cation in the separator are exchanged until the molar ratio of cation is the same as when immersed in the alkaline electrolyte. The molar ratio of cation in the genus fluctuates, reducing the charge and discharge cycle life.

By treating the sheet-like material containing the polyolefin-based synthetic resin fiber having an ion exchange group with the alkali electrolyte solution (e.g., 0.7 hydroxide potassium and 0.1 lithium lithium hydroxide) having the same type and concentration ratio as the alkaline electrolyte, When the separator including the ion exchange group in the form of a hydrophilic group is incorporated into the secondary battery, the blending ratio of the alkali metal ions incorporated in the separator is the same as the blending ratio when immersed in the alkaline electrolyte, and the alkali metal ions in the separator and the electrolyte solution. Since the replacement reaction of alkali metal ions in the interior does not occur, the molar ratio of alkali metal ions in the electrolyte can be kept constant. As a result, since the separator can maintain a sufficient amount of hydrophilic group, the electrolyte holding property of the separator can be improved and the charge / discharge cycle life of the nickel-hydrogen secondary battery can be improved.

In addition, the secondary battery provided with the separator can suppress the progress of self discharge when stored in a high temperature environment.

By increasing the ion exchange amount of the separator in the range of 0.2 to 2.0 meq / g, the hydrophilicity of the separator can be dramatically increased, and the battery withstand voltage when the charge / discharge cycle is repeated can be suppressed to increase the discharge cycle. It is possible to realize a nickel-hydrogen secondary battery having a greatly improved lifespan and an improved self-discharge characteristic under a high silver environment.

The method for manufacturing a nickel-hydrogen secondary battery according to the present invention includes a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator sandwiched between the positive electrode and the negative electrode, and an alkali. A method for producing a nickel-hydrogen secondary battery having an electrolyte solution, comprising: graft-copolymerizing a vinyl monomer having an ion exchange group by irradiating ultraviolet rays to a sheet-like material containing a polyolefin-based synthetic resin fiber that does not contain a light stabilizer, and the sheet-like article And a step of treating with an alkaline aqueous solution having the same kind and concentration ratio as the alkaline electrolyte.

According to this method, a nickel-hydrogen secondary battery having a separator containing a polyolefin-based synthetic resin fiber having an ion exchange group in the form of a salt as a hydrophilic group by treating with an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte can be manufactured and has a long lifetime. In addition, the secondary battery excellent in the self discharge characteristic at the time of high temperature storage can be implement | achieved.

In addition, according to the above method, the ion exchanger can be kept uniformly and in a moderate amount in the separator as compared with the case of irradiating the same amount of ultraviolet rays to the sheet-like material containing the polyolefin-based synthetic resin fiber containing the light stabilizer, and also the production of the separator. It can improve the efficiency.

That is, weathering stabilizers, such as antioxidants and light stabilizers, are added to polyolefin synthetic resin fibers, which are sheet-like materials, in order to suppress autooxidation deterioration caused by energy of heat or light. Among these weather stabilizers, the light stabilizer absorbs ultraviolet rays and converts them into harmless heat, kinetic and optical energy (phosphorescence, fluorescence) in polyolefin-based synthetic fibers, and releases them to the outside, or supplements radicals generated by ultraviolet rays to further radicals. It stops the chain reaction and has the function of suppressing the autooxidative degradation. As the light stabilizer, a hindered amine light stabilizer (HALS) having a high radical supplementation effect is widely used in styrene synthetic resins, polyurethanes, and the like in addition to polyolefin synthetic resin fibers. Although the amount of the light stabilizer added varies depending on the type of resin, it is usually about 100 to 1000 ppm.

Graft copolymerization of carbon radicals is stopped by the light stabilizer when graft copolymerization of a vinyl monomer having an ion exchange group by irradiating ultraviolet rays to a sheet-like material containing a polyolefin-based synthetic resin fiber containing such a light stabilizer. This is alienated. Therefore, when the amount of UV irradiation is the same as when irradiating sheet-like materials containing polyolefin-based synthetic resin fibers that do not contain light stabilizers, the graft copolymerization ratio of the light-containing stabilizer is lowered and the graft copolymerization is uneven to the sheet-like material. Therefore, the hydrophilicity of a separator falls. Further, when graft copolymerization of a vinyl monomer with a sufficient amount of vinyl monomer uniformly and in a sheet-like article containing a polyolefin-based synthetic resin fiber containing a light stabilizer is necessary to increase the amount of ultraviolet rays or irradiation time, the production efficiency of the separator is reduced.

When graft copolymerization of a vinyl vinylmer having an ion exchange group by irradiating ultraviolet rays to a sheet-like material containing polyolefin-based synthetic resin fibers containing no light stabilizer as described herein, the chain reaction of carbon radicals occurs quickly, As compared with the case, the vinyl monomer can be graft-copolymerized in a uniform and layered amount in the sheet-like article with a small amount of ultraviolet irradiation. Moreover, the autooxidation deterioration of the separator manufactured from the sheet form containing polyolefin synthetic resin fiber which does not contain a light stabilizer can be suppressed by antioxidant, and there exists no problem even if it does not have the said antioxidant in some cases. Therefore, when the graft co-polymerized sheet-like material is treated with an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte, the ion exchanger in the form of a salt is incorporated into the secondary battery as a separator. Self-discharge

A secondary battery excellent in the property can be obtained.

In addition, according to the above method, it is not necessary to consider the loss of the amount of ultraviolet irradiation by the light stabilizer, so that the graft copolymerization ratio can be easily controlled. In addition, the production efficiency of the separator can be improved.

The nickel-hydrogen secondary battery according to the present invention includes a negative electrode including a positive electrode containing nickel hydroxide and a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkali electrolyte solution. When the average diameter of all the fibers constituting the separator is set to X µm and the ion exchange amount of the separator is Ymeq / g, which is formed of a sheet-like material containing polyolefin-based synthetic resin fibers having a separator ion exchange group, they are the following (5) Satisfies equation (6),

The alkali electrolyte solution contains at least one of lithium oxalate or sodium hydroxide.

The separator satisfying the above formulas (5) and (6) and an alkali electrolyte solution containing at least one of sodium hydroxide or lithium hydroxide can be used to increase the self-discharge during the high temperature storage of the nickel-hydrogen secondary battery. It can polymerize. At the same time, the secondary battery can improve a large current discharge characteristic and a charge / discharge cycle life.

In addition, the ion exchange group distribution of the separator is assumed that the first surface is hydrophilic and the second surface has a hydrophilic portion and a hydrophobic portion, and the separator having such a configuration is disposed between the positive electrode and the negative electrode with the first surface on the positive electrode side. When placed in contact with each other, the self-discharge characteristics during high temperature storage of the secondary battery may be further improved.

When the nickel-hydrogen secondary battery is stored in a high temperature environment, the partial pressure of hydrogen in the battery increases due to the equilibrium pressure of the hydrogen storage alloy of the negative electrode. When the partial pressure of hydrogen in the battery rises, hydrogen gas may pass through the separator to reach the positive electrode, whereby NiOOH of the positive electrode may be reduced, that is, self discharge may occur. In the separator having the above-described configuration and arrangement, the amount of electrolyte on the positive electrode side can be increased as compared with that on the negative electrode side, so that a layer having a large amount of electrolyte solution on the positive electrode surface, that is, an electrolyte membrane, is scattered. The polymer can be prevented from penetrating the separator to the positive electrode. As a result, the self-discharge characteristics during high temperature storage are greatly improved.

You can.

In addition, the separator can impart water repellency to the negative electrode surface because the second surface having the hydrophilic and hydrophobic portions is in contact with the negative electrode surface. For this reason, the negative electrode is formed of the electrolyte on the surface and the surface and oxygen gas, and can increase the amount of three-phase interface that consumes oxygen gas generated from the positive electrode during overcharging. Since such negative electrodes can increase the oxygen gas consumption rate during overlayer display, the increase in the breakdown voltage during overcharge of the secondary battery can be suppressed. In addition, since the three-phase interface can also increase the absorption rate of hydrogen gas generated from the positive electrode at the time of reverse charging, the increase in the pressure resistance during reverse layer display can be suppressed by increasing the three-phase interface. Therefore, the separator of the above-described configuration and arrangement can increase the distribution of the electrolyte on the positive electrode side and control the hydrophobic portion to appear on the negative electrode side, so that the self-discharge characteristics at the time of high temperature storage are improved, and the withstand voltage increase at the time of over-evaporation is improved. A suppressed nickel secondary battery can be provided.

The nickel-hydrogen secondary battery according to the present invention includes a separator in which a sheet containing a water-repellent synthetic resin fiber and a sheet containing a synthetic resin fiber having hydrophilicity are integrated} and the separator includes a positive electrode and nickel containing hydrogen hydroxide. Said between the negative electrodes containing an alloy. The sheet | seat containing water-repellent synthetic resin fiber is arrange | positioned so that it may be located in the said negative pole side. As a result, water repellency can be imparted to the negative electrode surface in contact with the water-repellent synthetic resin fiber, so that a three-phase interface can be generated over the entire negative electrode surface, and the absorption rate and reverse charge of oxygen gas generated during overlaid charge It is possible to dramatically increase the absorption rate of hydrogen gas generated from the positive electrode at the time. Therefore, the secondary battery can significantly reduce the battery internal voltage during overcharge and reverse charge.

In addition, when the separator is made of only synthetic resin fibers of water-repellent resin, it is possible to improve the absorption rate of oxygen gas and hydrogen gas of the negative electrode, but the electrolyte holding property of the separator is decreased. Therefore, the charge / discharge cycle life is shortened. Since the separator of the secondary battery of the present invention is made by integrating a sheet containing a water-repellent synthetic resin fiber and a sheet containing a synthetic resin fiber having hydrophilic property, the sheet containing the synthetic resin fiber having hydrophilic property is excellent for a long time. It can have electrolyte holding performance. Therefore, the separator can reduce the amount of electrolyte in the portion facing the negative electrode surface where water repellency is required to improve the gas absorption performance, and can also maintain a large amount of the electrolyte over a long period of time except for this portion. The secondary battery provided with the separator can suppress an increase in the battery internal pressure during overcharging and reverse charging, and can also improve the charge / discharge cycle life.

In addition, since the sheet containing the synthetic resin fibers having the hydrophilicity of the separator is disposed in contact with the positive electrode, it is possible to form a layer having a large amount of electrolyte solution on the positive electrode surface. Such a layer having a large amount of electrolyte generates an electrolyte film on the positive electrode surface, thereby improving the high temperature storage characteristics of the nickel hydrogen secondary battery.

That is, in the Nigel hydrogen secondary battery, the hydrogen storage alloy of the negative electrode can occlude and discharge hydrogen gas by temperature and pressure. The hydrogen gas is absorbed and discharged electrochemically in place of temperature and pressure by utilizing the property of polymerizing and releasing hydrogen gas, and a secondary battery having a higher capacity than that of a nickel cadmium secondary battery is realized. The equilibrium pressure and hydrogen storage amount at each temperature of the hydrogen storage alloy are determined according to their composition. The equilibrium pressure and the hydrogen storage amount are slightly different depending on the composition of the hydrogen storage alloy, but generally, the equilibrium pressure increases and the hydrogen storage amount decreases with the increase in silver. When the hydrogen storage amount of the hydrogen storage alloy decreases, hydrogen gas which cannot be stored completely from the hydrogen storage alloy is released and the partial pressure of hydrogen in the battery increases. When the partial pressure of hydrogen in the battery rises, hydrogen gas passes through the separator to reduce NiOOH, which is a charge product of the positive electrode, to generate self-discharge.

When the sheet of synthetic resin fibers having the hydrophilicity on the positive electrode side as in the present invention is placed, the self-discharge can be prevented by the electrolyte membrane when the hydrogen gas reaches the positive electrode when the partial pressure of hydrogen in the electrode is increased by high temperature storage. It can be suppressed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

Example 1

[Production of past minus play]

Commercially available lantern-enriched Mitsch Metal (Lm) and Ni, Co polymerization NIn, A1 using LmNi4 oCoo. A hydrogen absorbing alloy having a composition of ⁴ Mno 3 Alo 3 was prepared. The hydrogen absorbing alloy was milled and passed through a 200-mesh sieve. 0.5 weight part of sodium polyacrylate, 0.125 weight part of carboxymethylcellulose (CMC), and the dispersion of polytetrafluoroethylene (non-increment l.5, 60 weight% of solid content) are 2.5 in solid content conversion with respect to 100 weight part of hydrogen storage alloy powders obtained. The paste was prepared by mixing 1.0 weight part of carbon powder with 50 weight part of water as a weight part and a electrically conductive material. The paste was applied to punched metal, dried, and pressed to form a paste-type negative electrode.

[Production of paste type positive play]

In a mixed powder consisting of 90 parts by weight of nickel hydroxide powder and 10 parts by weight of cobalt oxide powder, 0.3 parts by weight of carboxymethyl cellulose and polytetrafluoroethylene (weight ratio 1.5, solid content of 60% by weight) were converted into solid content with respect to the said nickel hydroxide powder. 0.5 weight part was added, 45 weight part of blunt water was added to these, and the paste was prepared by stirring. Subsequently, the paste was filled into a nickel plated fiber substrate, and the paste was applied to both surfaces thereof, dried, subjected to roller press, and rolled to produce a paste type positive electrode.

[Production of Separator]

From the polypropylene resin, a nonwoven fabric having an average fiber diameter of 1.0 mu m, a scale amount of 50 g / m ^2, and a thickness of 0.20 mm was produced by the melt blow method. Subsequently, the nonwoven fabric was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft copolymerize and wash the acrylic acid monomer to remove unreacted acrylic acid and dry the polypropylene fiber having a carboxyl group as an ion exchanger and a polypropylene fiber having no ion exchanger. The separator which consists of a nonwoven fabric and whose weight per unit area is 50.7g / m <^2> was produced.

As a result of measuring the graft copolymerization ratio of the acrylic acid monomer of the obtained separator by the above titration method, the amount of potassium ion exchange (Yo) per 1 g of separator was 0.2 rneq / g.

Next, the separator was sandwiched between the negative electrode and the plus electrode and wound in a vortex to form an electrode group. Such an electrode group, and 2.30 m1 of alkali electrolyte solution of about 9 N each containing KOH and LiOH in a molar ratio of 17: 1, were stored in a cylindrical container with a bottom, and had the structure shown in FIG. A cylindrical nickel-hydrogen secondary battery having a nominal capacity of 1.lAh1 and AA size was assembled.

Alkali-electrolyte equivalent (Xmeq / Ah) per 1 Ah of the battery capacity of the electrolyte solution contained in the container of the secondary battery described above in formula (I): X = (Zo × V) / Co (Zo = 9N, V = 2.30ml, Co = 1.1Ah) was 18.8. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituting in {0.636+ (2X / 55)}, the following formula (a) was obtained.

Moreover, the ion exchange amount (Y) per battery capacity of 1 Ah of the said separator is a formula (II); It was 0.10 meq / Ah when it calculated | required from Y = (Yo * DV) / Co (Yo = 0.2meq / g, W = 0.550g, Co = 1.1Ah).

Example 2

The same separator as in Example 1, the same plus electrode as in Example 1, and Example 1 except that the amount of potassium ion exchange (Yo) measured by the titration method was 0.4 (meq / g) and the weight (W) was 0.523 g. A nickel-hydrogen secondary battery was manufactured in the same manner as in Example 1 using the same negative electrode and the same electrolyte as in Example 1. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was found to be 19 meq / Ah from the above formula (II).

Example 3

The same separator as in Example 1, the same plus electrode as in Example 1, and Example 1, except that the amount of potassium ion exchange (Yo) measured by the titration method was 0.8 (meq / g) and the weight (W) was 0.495 g. A nickel-hydrogen secondary battery was manufactured in the same manner as in Example 1 using the same negative electrode and the same electrolyte as in Example 1. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.36 meq / Ah from the above formula (II).

Example 4

The same separator as in Example 1, the same plus electrode as in Example 1, and Example 1, except that the amount of potassium ion exchange (Yo) measured by the titration method was 1.5 (meq / g) and the weight (W) was 0.499 g. Nigel hydrogen secondary batteries were prepared in the same manner as in Example 1 using the same negative electrode and the same electrolyte as in Example l. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.68 meq / Ah from the above formula (II).

Example 5

The potassium ion exchange amount (Yo) measured by the titration method is 1.9 (meq / g) and the weight (W) is 0.492 g. The same object as in Example 1, the same plus electrode as in Example 1, and Example 1 A nickel-hydrogen secondary battery was manufactured in the same manner as in Example 1 using the same negative electrode and the same electrolyte as in Example 1. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 0.85 meq / Ah as determined from the above-described formula (II).

Example 6

The same separator as in Example 1, the same plus electrode as in Example 1, and Example 1, except that the amount of potassium ion exchange (Yo) measured by the titration method was 2.5 (meq / g) and the weight (W) was 0.506 g. A nickel-hydrogen secondary battery was manufactured in the same manner as in Example 1 using the same negative electrode and the same electrolyte as in Example 1. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.15 meq / Ah as determined from the formula (II).

Comparative Example 1

The same separator as in Example 1, the same plus electrode as in Example 1, and Example 1, except that the amount of potassium ion exchange (Yo) measured by the titration method was 3.1 (meq / g) and the weight (W) was 0.500 g. A nickel-hydrogen secondary battery was manufactured in the same manner as in Example 1 using the same negative electrode and the same electrolyte as in Example 1. The ion exchange amount (Y) per battery capacity lAh of the separator of the obtained secondary battery was found to be 1.41 meq / Ah from the above formula (II).

After charging 150% at 1CmA with respect to the obtained secondary battery of Examples 1-6 and Comparative Example 1, the charge cycle which discharged until 1V of a battery voltage reaches 1.0V was repeated 3 cycles. The discharge capacity of this 3rd cycle was made into initial stage capacity. After that, the increase and discharge cycles were repeated under the same conditions, and the number of repetitions until the discharge capacity dropped to 80% of the initial capacity was measured to determine the charge and discharge cycle life of the battery, and the results are shown in Table 1 below.

As apparent from Table 1, the secondary batteries of Examples 1 to 6 in which the ion exchange amount (Y) of the separator was 0.067 to l.32 (meq / Ah) had a longer charge / discharge cycle life than the secondary batteries of Comparative Example 1. It can be seen that.

Example 7

The same nonwoven fabric as in Example 1 was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet rays to graft copolymerize and wash the acrylic acid monomer to remove unreacted acrylic acid and dry the polypropylene fiber having a carboxyl group as an ion exchange group and a poly without ion exchange group. A separator made of a propylene fiber nonwoven fabric having a weight per unit area of 51.5 g / m ² and a potassium ion exchange amount (Yo) of 0.4 meq / g by the titration method was prepared.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. The electrode group and the alkaline electrolyte solution 2.30 m1 of the prescribed degree containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom, and have the structure shown in FIG. 1 above. ) Is 1.1 Ah, and AA size cylindrical nickel-hydrogen secondary battery was assembled.

Alkaline electrolyte equivalent (Xmeq / Ah) per 1Ah of battery capacity of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 7N, V = 2.30ml, Co = 1.lAh), 14.6 It was. Obtained X was substituted into said Formula (1) and {0.409- (X / 55)} <= Y <{0.636+ (2X / 55)}, and the following (b) formula was obtained.

Moreover, it was 0.19 meq / Ah when the ion exchange amount (Y) per battery capacity of the said separator was calculated | required from said Formula (II) (Yo = 0.4meq / g, W = 0.523g, Co = l.lAh).

Example 8

A nickel-hydrogen secondary battery similar to Example 7 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 0.8 (meq / g) and the weight (W) was 0.509 g. It was 0.37 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Example 9

A nickel-hydrogen secondary battery similar to Example 7 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the WND amount (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.69 meq / Ah as determined from the above-described formula (II).

Example 10

A nickel-hydrogen secondary battery similar to Example 7 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.9 (meq / g) and the amount of increase (W) was 0.498 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.86 meq / Ah as determined from the above-described formula (II).

Example 11

A nickel-hydrogen secondary battery similar to Example 7 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.502 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.14 meq / Ah as determined from the formula (II).

Comparative Example 2

A nickel-hydrogen secondary battery similar to Example 7 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.2 (meq / g) and the weight (W) was 0.605 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was found to be 0.llmeq / Ah from the above formula (II).

Comparative Example 3

A nickel-hydrogen secondary battery similar to Example 7 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.1 (meq / g) and the amount of increase (W) was 0.500 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.41 meq / Ah as determined from the formula (II).

Polymerization to Secondary Batteries of Examples 7-1 and Comparative Examples 2-3 Obtained The charging and discharging cycle life of the battery was obtained in the same manner as described above, and the results are shown in Table 2 below.

As apparent from Table 2, the secondary batteries of Examples 7 to 11 in which the ion exchange amount (Y) of the separator was 0.14 to 1.17 (meq / Ah) had a longer charge / discharge cycle life than the secondary batteries of Comparative Examples 2 to 3. It can be seen that.

Example 12

The same nonwoven fabric as in Example 1 was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet light to graft copolymerize the acrylic acid monomer, and then washed to remove unreacted acrylic acid and dried to obtain a polypropylene fiber and a polypropylene fiber nonwoven fabric having a carboxyl group as an ion exchanger. A separator having a weight per unit area of 51.5 g / m ² and a potassium ion exchange amount (Yo) of 0.4 meq / g by the titration method was prepared.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. The electrode group and 2.0 ml of an alkaline electrolyte solution of about 7 grams containing KOH and LiOH in a molar ratio of 17: 1 were housed in a cylindrical container with a bottom and had the structure shown in FIG. 1 above. ) Is a 1Ah and AA cylindrical nickel-hydrogen secondary battery was assembled.

Alkaline electrolyte equivalent (Xmeq / Ah) per 1Ah of battery capacity of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 7N, V = 2.0rnl, Co = 1.lAh), 12.7 It was. Obtained X was substituted into said Formula (1) and {0.409- (X / 55)} <= Y <{0.636+ (2X / 55)}, and the following (c) formula was obtained.

The ion exchange amount (Y) per lAh of the battery capacity of the separator was calculated from the above formula (II) (Yo = 0.4 meq / g, W = 0.495 g, Co = 1.1 Ah) and 0.18 meq / Ah.

Example 13

A nickel-hydrogen secondary battery similar to Example 12 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 0.8 (meq / g) and the weight (W) was 0.509 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.37 meq / Ah from the above formula (II).

Example 14

A nickel-hydrogen secondary battery similar to Example 12 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the increase amount (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.69 meq / Ah as determined from the above-described formula (II).

Example 15

A nickel-hydrogen secondary battery similar to Example 12 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 1.9 (meq / g) and the weight (W) was 0.504 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 0.87 meq / Ah as determined from the formula (II).

[Comparative Example 4]

A nickel-hydrogen secondary battery similar to Example 12 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 0.2 (meq / g) and the weight (W) was 0.550 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.10 meq / Ah from the above formula (II).

[Comparative Example 5]

A nickel-hydrogen secondary battery similar to Example 12 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 1.15 meq / Ah based on the above formula (II).

Comparative Example 6

A nickel-hydrogen secondary battery similar to Example 12 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.1 (meq / g) and the weight (W) was 0.504 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 1.42 meq / Ah from the above formula (II).

About the secondary battery of Examples 12-15 and Comparative Examples 4-6 which were obtained, charge / discharge cycle life was calculated | required similarly to the above, and the result is shown in following Table 3. 5 shows a change in cycle life when the ion exchange amount Y (meq / Ah) per battery capacity of the separator is changed.

As apparent from Tables 3 and 5, the ion exchange amount (Y) of the separator was 0.178-1. It is understood that the secondary batteries of Examples 12 to 5, which are 10 (meq / Ah), have a longer charge / discharge cycle life than the secondary batteries of Comparative Examples 4 to 6.

Example 16

The same nonwoven fabric as in Example 1 was dipped in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer, followed by washing to remove unreacted acrylic acid and drying, thereby making polypropylene fiber and polypropylene fiber having a carboxyl group as an ion exchanger. A separator made of a nonwoven fabric having a weight of 52.8 g / m ² and a potassium ion exchange amount (Yo) of 0.8 meq / g by the titration method was prepared.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. Such electrode group and 2.30 ml of alkaline electrolyte solution of about 5 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom and have the structure shown in FIG. 1 above. ) Is 1.lAh and AA size cylindrical nickel-hydrogen secondary battery was assembled.

The alkaline electrolyte equivalent (Xmeq / Ah) per battery capacity of 1 Ah of the electrolyte contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 5N, V = 2.30 ml, Co = 1.1 Ah), and 10.5. . Obtained X is represented by said (l) formula, {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (d) was obtained.

The ion exchange amount (Y) per 1 Ah of battery capacity of the separator was calculated from the above formula (II) (Yo = 0.8rneq / g, W = 0.495g, Co = 1.lAh), and 0.36meq / Ah.

Example 17

A nickel-hydrogen secondary battery similar to Example 16 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the weight (W) was 0.499 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.68 meq / Ah from the above formula (II).

Example 18

A nickel-hydrogen secondary battery similar to Example 16 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.9 (meq / g) and the weight (W) was 0.498 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.86 meq / Ah as determined from the above-described formula (II).

Comparative Example 7

A nickel-hydrogen secondary battery similar to Example 16 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 0.2 (meq / g) and the weight (W) was 0.550 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.1 meq / Ah from the above formula (II).

Comparative Example 8

A nickel-hydrogen secondary battery similar to Example 16 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.48 (meq / g) and the weight (W) was 0.435 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.19 meq / Ah from the above formula (II).

Comparative Example 9

A nickel-hydrogen secondary battery similar to Example 16 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.15 meq / Ah as determined from the formula (II).

Comparative Example 10

A nickel-hydrogen secondary battery similar to Example 1 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.1 (meq / g) and the weight (W) was 0.500 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.41 meq / Ah as determined from the formula (II).

The obtained secondary batteries of Examples 16 to 18 and Comparative Examples 7 to 10 were obtained in the same manner as described above, and the increase and discharge cycle life of the batteries were obtained, and the results are shown in Table 4 below.

As apparent from Table 4, the secondary batteries of Examples 16 to 18 in which the ion exchange amount (Y) of the separator was 0.22 to 1.02 (meq / Ah) had a longer charge / discharge cycle life than the secondary batteries of Comparative Examples 7 to 10. It can be seen that.

Example 19

The same nonwoven fabric as in Example 1 was dipped in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer, followed by washing to remove unreacted acrylic acid and drying, thereby making polypropylene fiber and polypropylene fiber having a carboxyl group as an ion exchanger. A separator composed of a nonwoven fabric having a weight of 52.8 g / m ² and a potassium ion exchange amount (Yo) of 0.8 rneq / g by the titration method was prepared.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a spiral to form an electrode group. The electrode group and the alkaline electrolyte solution of about 5 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom, and have the structure shown in FIG. 1 above. ) Is 1.lAh and AA size win-type nickel-metal hydride secondary battery was assembled.

The alkali electrolyte equivalent (Xmeq / Ah) per lAh of battery capacity of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 5N, V = 1.75ml, Co = 1.lAh), 7.95 It was. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (e) was obtained.

The ion exchange amount (Y) per 1 Ah of battery capacity of the separator was calculated from the above formula (II) (Yo = 0.8 meq / g, W = 0.495 g, Co = 1.1 Ah) and 0.36 meq / Ah.

Example 20

A nickel-hydrogen secondary battery similar to Example 19 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the weight (W) was Q · 513g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.70 meq / Ah from the above formula (II).

Example 21

A nickel-hydrogen secondary battery similar to Example 19 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.9 (meq / g) and the weight (W) was 0.498 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.86 rneq / Ah as determined from the above-described formula (II).

Comparative Example 11

A nickel-hydrogen secondary battery similar to Example 1 was manufactured except that the potassium ion exchange amount (Yo) measured by the separator titration method was 0.2 (meq / g) and the weight (W) was 0.550 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.10 rneq / Ah from the above formula (II).

Comparative Example 12

A nickel-hydrogen secondary battery similar to Example 19 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the amount of increase (W) was 0.468 g. It was 0.17 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 13

A nickel-hydrogen secondary battery similar to Example 19 was produced except that the amount of potassium ion exchange (Yo) measured by the titration method of the separator was 2.5 (meq / g) and the increase (enter V) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be l.15 meq / Ah from the above formula (II).

Comparative Example 14

A nickel-hydrogen secondary battery similar to Example 19 was produced except that the amount of potassium ion exchange (Yo) measured by the titration method of the separator was 3.1 (meq / g) and the increase (W) was 0.500 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.41 meq / Ah as determined from the formula (II).

The obtained secondary batteries of Examples 19 to 21 and Comparative Examples 11 to 14 were obtained in the same manner as described above to obtain the charge and discharge cycle life of the battery, and the results are shown in Table 5 below.

Serve

As apparent from Table 5, the secondary batteries of Examples 19 to 2 with the ion exchange amount (Y) of the separator being 0.26 to 0.93 (meq / Ah) had a longer charge / discharge cycle life than the secondary batteries of Comparative Examples 11 to 14. It can be seen that.

Comparative Example 15

The same nonwoven fabric as in Example 1 was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer, followed by washing to remove unreacted acrylic acid and drying the polypropylene fiber and polypropylene fiber nonwoven fabric having a carboxyl group as an ion exchanger. A separator having a weight per unit area of 50.7 g / m ² and a potassium ion exchange amount (Yo) of 0.2 meq / g by the titration method was prepared.

Next, the separator was sandwiched between the same negative electrode as in Example 1 and the plus electrode as in Example 1, and the electrode group was produced by winding it around. The electrode group and 2.30 ml of alkaline electrolyte solution of about 4 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom and have the structure shown in FIG. 1 above. ) Is 1.lAh and AA size cylindrical nickel-hydrogen secondary battery was assembled.

The alkaline electrolyte equivalent (Xrneq / Ah) per battery capacity of 1 Ah of the electrolyte solution contained in the container of the secondary battery was found from the above formula (I) (Zo = 4N, V = 2.30rnl, Co = 1.lAh) of 8.4. . Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (f) was obtained.

Moreover, it was 0.10 meq / Ah (Yo = 0.2meq / g, W = 0.550g, Co = 1.lAh) calculated | required the ion exchange amount (Y) per battery capacity of the said separator from said Formula (II).

[Comparative Example 16]

A nickel-hydrogen secondary battery similar to Comparative Example 15 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.523 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.19 meq / Ah from the above formula (II).

[Comparative Example 17]

A nickel-hydrogen secondary battery similar to Comparative Example 15 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.8 (meq / g) and the amount of increase (W) was 0.495 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.36 meq / Ah from the above formula (II).

[Comparative Example 18]

A nickel-hydrogen secondary battery similar to Comparative Example 15 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.69 rneq / Ah from the above formula (II).

Comparative Example 19

Potassium ion exchange amount (Yo) measured by the titration method of separator is 1.9 (meq / g)

And a nickel-hydrogen secondary battery similar to Comparative Example 15 was manufactured except that the weight (W) was 0.504 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.87 rneq / Ah as determined from the above-described formula (II).

[Comparative Example 20]

A nickel-hydrogen secondary battery similar to Comparative Example 15 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.502 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.14 meq / Ah as determined from the formula (II).

Comparative Example 21

A nickel-hydrogen secondary battery similar to Comparative Example 15 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.1 (meq / g) and the weight (W) was 0.500 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.41 meq / Ah as determined from the formula (II).

The layer discharge cycle life of the battery was obtained in the same manner as described above for the obtained secondary batteries of Comparative Examples 15 to 21, and the results are shown in Table 6 below.

As is apparent from Table 6, it can be seen that the secondary batteries of Comparative Examples 15 to 21 were both short in charge and discharge cycle life.

In the secondary batteries of Examples 1 to 21, the vertical axis represents the battery capacity of the separator of 1 Ah.

The cycle life obtained on the coordinate axis of the ion exchange amount (Y) of sugar (meq / Ah) and the horizontal axis of alkali electrolyte equivalent (X) (meq / Ah) per battery capacity is shown, and the results are shown in FIG. .

In the nickel-hydrogen secondary battery having a separator containing a polyolefin-based synthetic resin fiber having an ion exchange group and an alkali electrolyte having a concentration of about 5 or more, as shown in FIG. 6, the ion exchange amount per 1 Ah of the battery capacity of the separator (Y (meq / Ah) is the formula (1); {0.409- (X / 55)} Y It can be seen that the secondary battery that satisfies {0.636+ (2X / 55)} has a longer charge / discharge cycle life than the secondary battery in which the ion exchange amount (Y) deviates from the above formula (1).

On the other hand, it can be seen that the secondary batteries of Comparative Examples 15 to 21 equipped with the alkali electrolyte solution of 4 regulations have a short cycle life even if the ion exchange amount (Y) satisfies the above formula (1). This is attributable to the low conductivity of the alkali electrolyte at the above concentration.

do.

Example 22

Long average fiber diameter of 10 µm from polypropylene resin

A nonwoven fabric made of fibers, with a scale of 50 g / m ² and a thickness of 0.20 mm, was produced. Subsequently, a first roll having a smooth surface and a second roll having a plurality of pinpoint irregularities formed on the surface thereof are disposed to face each other, and the nonwoven fabric is passed between the rolls so that the first roll and the second roll are separated. The embossing was performed by pressurizing at the convex portion and thermally fusion bonding. The area of the heat-sealed portion by this embossing was 16% of the area of one side of the separator. Subsequently, the nonwoven fabric was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer, wash, remove unreacted acrylic acid, and dry it to form a polypropylene fiber having a carboxyl group and a polypropylene fiber nonwoven fabric as an ion exchanger. A separator having a weight of 51.0 g / m ² and a potassium ion exchange amount (Yo) of 0.3 meq / g by the titration method was produced.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. Such a whole grain group and 2.30 ml of an alkaline electrolyte solution of about 9 sizes containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom and have the structure shown in FIG. 1 above. ) Is 1.lAh and AA cylindrical Nigel hydrogen secondary battery was assembled.

The alkali electrolyte equivalent (Xmeq / Ah) per 1 Ah of the battery capacity of the electrolyte solution contained in the container of the secondary battery (I); X = (Zo × V) / Co (Zo = 9N, V = 2.30 ml, Co = 1.lAh, which was 18.8. The obtained X was obtained by the above formula (1), {0.409- (X / 55)}. Y Substituted in (0.636+ (2X / 55)), the following formula (A) was obtained.

Moreover, the ion exchange amount (Y) per battery capacity of 1 Ah of the said separator is formula (II); It was 0.14 meq / Ah obtained from Y = (YoW) / Z (Yo = 0.3meq / g, W = 0.5l3g, Co = 1.1Ah).

Example 23

A nickel-hydrogen secondary battery similar to Example 22 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.495 g. It was 0.18 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Example 24

A nickel-hydrogen secondary battery similar to Example 22 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.6 (meq / g) and the weight (W) was 0.513 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.28 meq / Ah from the above formula (II).

Example 25

A nickel-hydrogen secondary battery similar to Example 22 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.0 meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was determined to be 0.46 meq / Ah from the above formula (II).

Example 26

A nickel-hydrogen secondary battery similar to Example 22 was produced except that the amount of potassium ion exchange (Yo) measured by a separator titration method was 2.0 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.92 meq / Ah as determined from the above-described formula (II).

Example 27

A nickel-hydrogen secondary battery similar to Example 22 was produced except that the amount of potassium ion exchange (Yo) measured by the titration method of the separator was 2.4 (meq / g) and the weight (W) was 0.509 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.11 meq / Ah as determined from the formula (II).

Comparative Example 22

A nickel-hydrogen secondary battery similar to Example 22 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.0 (meq / g) and the weight (W) was 0.502 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 1.37 meq / Ah from the above formula (II).

The secondary batteries of Examples 22 to 27 and Comparative Example 22 obtained were obtained in the same manner as described above, and the charge and discharge cycle lifespan of the batteries were obtained, and the results are shown in Table 7 below.

As is apparent from Table 7, the secondary batteries of Examples 22 to 27 having a separator having an ion exchange amount (Y) (meq / Ah) of 0.067 to 1.32 were equipped with a separator whose ion exchange amount (Y) was out of the above range. It can be seen that the charge and discharge cycle life is longer than that of the secondary battery of Comparative Example 22.

Example 28

The same nonwoven fabric as in Example 22 was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer, followed by washing to remove unreacted acrylic acid and drying the polypropylene fiber and polypropylene fiber nonwoven fabric having a carboxyl group as an ion exchanger. A separator having a weight per unit area of 51.5 g / m ² and a potassium ion exchange amount (Yo) by a constituent method of 0.4 meq / g was produced.

Next, the separator was sandwiched between the same negative electrode as in Example 1 and the plus electrode as in Example 1, and wound around in a vortex to produce an electrode group. Such electrode group and 2.30 m1 of alkaline electrolyte solution of about 7 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom and have the structure shown in FIG. 1 above. ) Was l.lAh and AA size cylindrical nickel-hydrogen secondary batteries were roughened.

Alkaline electrolyte equivalent (Xmeq / Ah) per 1Ah of battery capacity of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 7N, V = 2.30ml, Co = 1.lAh), 14.6. It was. Obtained X is represented by the above-mentioned formula (l), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (B) was obtained.

The ion exchange amount (Y) per 1 Ah of battery capacity of the separator was obtained from the above formula (II) (Yo = Q.4meq / g, W = 0,495g, Co = 1.lAh), and 0.18rneq / Ah. .

Example 29

A nickel-hydrogen secondary battery similar to Example 28 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.6 (meq / g) and the weight (W) was 0.513 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.28 meq / Ah from the above formula (II).

Example 30

A nickel-hydrogen secondary battery similar to Example 28 was produced except that the potassium ion exchange amount (Yo) measured by the separator titration method was 1.0 (meq / g) and the weight (W) was 0.495 g. It was 0.45 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Example 31

A nickel-hydrogen secondary battery similar to Example 28 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 2.0 (meq / g) and the weight (W) was 0.50 lg. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.91 meq / Ah as determined from the above-described formula (II).

Example 32

The potassium ion exchange amount (Yo) measured by the titration method of the separator was 2.4 (meq / g), and the weight (W) was 0.504 g, which produced the same nickel-hydrogen secondary battery as in Example 28. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 1.10 meq / Ah based on the above formula (II).

Comparative Example 23

A nickel-hydrogen secondary battery similar to Example 28 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.3 (meq / g) and the weight (W) was 0.513 g. It was 0.14 meq / Ah when the ion exchange amount (Y) per 1 Ah of displacement capacity of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 24

A nickel-hydrogen secondary battery similar to Example 28 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.0 (meq / g) and the weight (W) was 0.502 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be l.37 meq / Ah from the above formula (II).

The obtained secondary batteries of Examples 28 to 32 and Comparative Examples 23 to 24 were obtained in the same manner as described above, and the charge and discharge cycle life of the batteries were obtained, and the results are shown in Table 8 below.

As is apparent from Table 8, the secondary batteries of Examples 28 to 32 equipped with a separator having an ion exchange amount (Y) (meq / Ah) of 0.143 to 1.17 were equipped with a separator whose ion exchange amount (Y) was outside the above range. It can be seen that the charge and discharge cycle life is longer than that of the secondary batteries of Comparative Examples 23 to 24.

Example 33

The same nonwoven fabric as in Example 22 was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer, followed by washing to remove unreacted acrylic acid and drying the polypropylene fiber and polypropylene fiber nonwoven fabric having a carboxyl group as an ion exchanger. A separator having a weight of 52.lg / m ² and a potassium ion exchange amount (Yo) of 0.6 meq / g by the titration method was prepared.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. The electrode group and the alkaline electrolyte solution of about 5 s, including KOH and LiOH in a molar ratio of 17: 1, were stored in a cylindrical container with a bottom of 5 in a cylindrical container with a bottom and had the structure shown in FIG. 1 above. ) Is 1.lAh and AA size cylindrical nickel-hydrogen secondary battery was assembled.

The alkali electrolytic liquid equivalent (Xmeq / Ah) per battery capacity of 1 Ah of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 5N, V = 2.30 ml, Co = 1.lAh), 10.5. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (C) was obtained.

The ion exchange amount (Y) per battery capacity of the separator (A) was calculated from the above formula (II) (Yo = 0.6 meq / g, W = 0.515 g, Co = 1.1 Ah) and 0.28 meq / Ah.

Example 34

A nickel-hydrogen secondary battery similar to Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.0 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was determined to be 0.46 meq / Ah from the above formula (II).

Example 35

A nickel-hydrogen secondary battery similar to Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 2.0 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.92 meq / Ah as determined from the above-described formula (II).

[Comparative Example 25]

Potassium ion exchange amount (Yo) measured by the titration method of the separator is 0.3 (meq / g)

And a Nigel hydrogen secondary battery similar to Example 33 was prepared except that the weight (W) was 0.550 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was found to be 0.15 meq / Ah from the above formula (II).

Comparative Example 26

A nickel-hydrogen secondary battery similar to Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.523 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.19 meq / Ah from the above formula (II).

Comparative Example 27

A nickel-hydrogen secondary battery similar to Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 4.2 (meq / g) and the weight (W) was 0.509 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.11 meq / Ah as determined from the formula (II).

Comparative Example 28

A nickel-hydrogen secondary battery similar to Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.0 (meq / g) and the weight (W) was 0.499 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 1.36 meq / Ah based on the above formula (II).

About the secondary battery of Examples 33-35 and Comparative Examples 25-28 which were obtained, it carried out similarly to the above, and calculates the charge / discharge cycle life of a battery, and shows the result in Table 9 below.

As is apparent from Table 9, the secondary batteries of Examples 33 to 35 having a separator having an ion exchange amount (Y) (meq / Ah) of 0.218 to 1.02 were equipped with a separator whose ion exchange amount (Y) was outside the above range. It can be seen that the charge and discharge cycle life is longer than that of the secondary batteries of Comparative Examples 25 to 28.

Example 36

The same nonwoven fabric as in Example 22 was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet light to graft copolymerize the acrylic acid monomer, and then washed to remove unreacted acrylic acid and dried to remove polypropylene fiber and polypropyllian fiber nonwoven fabric having a carboxyl group as an ion exchanger. And a separator having a weight per unit area of 52.8 g / m ² and a potassium ion exchange amount (Yo) of 0.8 meq / g by the titration method.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. The electrode group and the alkaline electrolyte solution of about 5 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom, and have the structure shown in FIG. 1 above. ) Is l.lAh and AA size cylindrical nickel-hydrogen secondary battery was assembled.

Alkaline electrolyte equivalent (Xmeq / Ah) per 1Ah of battery capacity of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 5N, V = 1.75ml, Co = 1.lAh), 7.95 It was. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (D) was obtained.

In addition, the ion exchange amount (Y) per 1 Ah of battery capacity of the separator described above is formula (II)

It was calculated | required from (Yo = 0.8meq / g, W = 0.495g, Co = 1. LAh), and 0.36meq / Ah.

Example 37

A nickel-hydrogen secondary battery similar to Example 36 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the weight (W) was 0.513 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.70 meq / Ah from the above formula (II).

Example 38

Potassium ion exchange amount (Yo) measured by the titration method of separator is 1.9 (meq / g)

And a nickel-hydrogen secondary battery similar to Example 36 was produced except that the weight (W) was 0.498 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.86 meq / Ah as determined from the above-described formula (II).

Comparative Example 29

A nickel-hydrogen secondary battery similar to Example 36 was produced except that the amount of potassium ion exchange (Yo) measured by a separator titration method was 0.2 (meq / g) and the weight (W) was 0.550 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.10 meq / Ah from the above formula (II).

Comparative Example 30

A nickel-metal hydride secondary battery similar to Example 36 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.468 g. The ion exchange amount (Y) per 1 Ah of battery capacity of the separator of the obtained secondary battery was found to be 0.17 meq / Ah from the above formula (II). '

Comparative Example 31

A nickel-hydrogen secondary battery similar to Example 36 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.15 rneq / Ah as determined from the above-described formula (II).

Comparative Example 32

A nickel-hydrogen secondary battery similar to Example 36 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.1 (meq / g) and the weight (W) was 0.500 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.41 meq / Ah as determined from the formula (II).

The obtained secondary batteries of Examples 36 to 38 and Comparative Examples 29 to 32 were obtained in the same manner as described above, and the charge and discharge cycle life of the batteries were obtained, and the results are shown in Table 10 below.

As is apparent from Table 10, the secondary batteries of Examples 36 to 38 provided with a separator having an ion exchange amount (Y) (meq / Ah) of 0.26 to 0.93 were equipped with a separator whose ion exchange amount (Y) was outside the above range. It can be seen that the charge and discharge cycle life is longer than that of the secondary batteries of Comparative Examples 29 to 32.

Example 33

The same nonwoven fabric as in Example 22 was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet light to graft copolymerize the acrylic acid monomer, followed by washing to remove unreacted acrylic acid and drying the polypropylene fiber and polypropylene fiber nonwoven fabric having a carboxyl group as an ion exchanger. A separator having a weight per unit area of 51.0 g / m ² and a potassium ion exchange amount (Yo) of 0.3 meq / g by a titration method was prepared.

Next, the separator was sandwiched between the same negative electrode as in Example 1 and the positive electrode as in Example 1, and wound around to form an electrode group. The electrode group and the KAL and LiOH containing the alkaline electrolyte solution 2.30m1 of about 4 specifications containing the molar ratio of 17: 1 is stored in the cylindrical container with a bottom, and has the structure shown in FIG. 1 above, and battery capacity (nominal capacity) ), And a cylindrical nickel-hydrogen secondary battery of AA size was assembled.

Alkaline electrolyte equivalent (Xmeq / Ah) per 1Ah of battery capacity of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 4N, V = 2.30ml, Co = 1.1Ah), 8.4 It was. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (E) was obtained.

The ion exchange amount (Y) per 1 Ah of battery capacity of the separator was calculated from the above formula (II) (Yo = Q.3meq / g, W = 0.513g, Co = 1.lAh), and 0.14meq / Ah. .

Comparative Example 34

A nickel-hydrogen secondary battery was prepared in the same manner as in Comparative Example 33 except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.495 g. It was 0.18 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 35

A nickel-hydrogen secondary battery similar to Comparative Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.6 (meq / g) and the weight (W) was 0.495 g. It was 0.27 meq / Ah when ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from Formula (II) mentioned above.

Comparative Example 36

A nickel-hydrogen secondary battery similar to Comparative Example 33 was produced except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.0 (meq / g) and the weight (W) was 0.495 g. It was Q.45meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 37

A nickel-hydrogen secondary battery similar to Comparative Example 33 was produced except that the potassium ion exchange amount (Yo) measured by the separator titration method was 2.0 (meq / g) and the weight (W) was 0.506 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 0.92 meq / Ah as determined from the above-described formula (II).

[Comparative Example 38]

A nickel-hydrogen secondary battery similar to Comparative Example 33 was produced except that the potassium ion exchange amount (Yo) measured by the separator titration method was 2.4 (meq / g) and the weight (W) was 0.509 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 1.11 meq / Ah as determined from the formula (II).

Comparative Example 39

A nickel-hydrogen secondary battery was prepared in the same manner as in Comparative Example 33 except that the potassium ion exchange amount (Yo) measured by the titration method of the separator was 3.0 (meq / g) and the weight (W) was 0.499 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 1.36 meq / Ah based on the above formula (II).

The charge and discharge cycle life of the battery was determined in the same manner as described above for the obtained secondary batteries of Comparative Examples 33 to 39, and the results are shown in Table 11 below.

As apparent from Table 11, it can be seen that the secondary batteries of Comparative Examples 33 to 39 have a short charge / discharge cycle life.

In addition, with respect to the secondary batteries of Examples 22 to 38, the vertical axis represents the battery capacity of the separator of 1 Ah.

The cycle life obtained on the coordinate axis of the ion exchange amount (Y) of sugar (meq / Ah) and the horizontal axis of alkali electrolyte equivalent (X) (meq / Ah) per battery capacity lAh is shown, and the result is shown in FIG. .

In the nickel-hydrogen secondary battery having a separator containing a polyolefin-based synthetic resin fiber having an ion exchange group and an alkali electrolyte having a concentration of about 5 or more, as shown in FIG. 7, the ion exchange amount per battery capacity lAh of the separator (Y (meq / Ah) is the formula (1); {0.409- (X / 55)} Y It can be seen that the secondary battery that satisfies {0.636+ (2X / 55)} has a longer charge / discharge cycle life than the secondary battery in which the ion exchange amount (Y) deviates from the above formula (1).

On the other hand, it can be seen that the secondary batteries of Comparative Examples 33 to 39, each of which had an alkali electrolyte solution having a concentration of 4, had a short cycle life even if the ion exchange amount (Y) satisfied the above formula (l). This is attributable to the low conductivity of the alkali electrolyte at the above concentration.

By comparing the cycle characteristics of the secondary batteries of Examples 1 to 21 and the secondary batteries of Examples 22 to 38, the secondary batteries having an average fiber diameter of 1 µm in the total fibers included in the separator had an average fiber diameter of 10 µm. It can be seen that the cycle life is longer than that of the secondary battery.

Example 39

The same nonwoven fabric as in Example 1 was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft co-polymerize the acrylic acid monomer, and then washed to remove unreacted acrylic acid and dried to obtain a polypropylene fiber and a polypropylten fiber nonwoven fabric having a carboxyl group as an ion exchanger. And a separator having a weight per unit area of 52.8 g / m ² and a potassium ion exchange amount (Yo) of 0.8 meq / g by the titration method.

Next, the separator was sandwiched between the negative electrode as in Example 1 and the positive electrode as in Example 1, and wound in a vortex to form an electrode group. Such electrode roots, and 2.4 m1 of alkaline electrolyte solution of about 7 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom, and have the structure shown in FIG. 1 above. ) Was assembled with a cylindrical nickel-sustainable secondary battery of 1.8 Ah and a 4 / 5A size.

Alkaline electrolyte equivalent (Xmeq / Ah) per 1Ah of battery capacity of the electrolyte contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 7N, V = 2.4ml, Co = 1.8Ah), 9.33 It was. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substitution of {0 '636+ (2X / 55)} gave the following formula (G).

The ion exchange amount (Y) per 1 Ah of battery capacity of the separator was calculated from the above formula (II) (Yo = 0.8 meq / g, W = 0.585 g, Co = 1.8 Ah) and 0.26 meq / Ah.

Example 40

A nickel-hydrogen secondary battery similar to Example 39 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 1.5 (meq / g) and the weight (W) was 0.612 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.51 meq, / Ah from the above formula (II).

Example 41

A nickel-hydrogen secondary battery similar to Example 39 was assembled except that the potassium ion exchange amount (Yo) was 1.9 (meq / g) and the weight (W) was 0.597 g, which was measured by a separator titration method. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the secondary battery was 0.63 meq / Ah as determined from the above formula (II).

Example 42

A nickel-hydrogen secondary battery similar to Example 39 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.612 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was 0.85 meq / Ah as determined from the above-described formula (II).

[Comparative Example 40]

A nickel-hydrogen secondary battery similar to Example 39 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0/2 (meq / g) and the weight (W) was 0.630 g. It was 0.07 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 41

A nickel-hydrogen secondary battery similar to Example 39 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.585 g. The ion exchange amount (Y) per 1Ah of the battery capacity of the separator of the obtained secondary battery was found to be 0.13rneq / Ah from the above formula (II).

Comparative Example 42

A nickel-hydrogen secondary battery similar to Example 39 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 3.1 (meq / g) and the amount of increase (W) was 0.592 g. Ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery (Y). It was 1.02 meq / Ah when calculated | required from said Formula (II).

The secondary batteries of Examples 39 to 42 and Comparative Examples 40 to 42 obtained were obtained in the same manner as described above, and the charge and discharge cycle lifespan of the batteries were obtained, and the results are shown in FIG.

As is apparent from FIG. 8, the ion exchange amount Y (meq / Ah) is represented by the formula (l); {0.409- (X / 55)} Y The secondary battery of Examples 39-42 which had a separator which satisfy | fills {0.636+ (2X / 55)} is an Example provided with the separator whose ion-exchange amount (Y) (meq / Ah) deviates from said Formula (1). It can be seen that the charge and discharge cycle life is longer compared with the secondary batteries of 40 to 42.

Example 43

The same nonwoven fabric as in Example 1 was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet rays to graft co-polymerize the acrylic acid monomer, and then washed to remove unreacted acrylic acid, followed by drying to obtain a polypropylene fiber and a polypropylene fiber nonwoven fabric having a carboxyl group as an ion exchanger. And a separator having a weight of 52.8 g / m ² and a potassium ion exchange amount (Yo) of 0.8 meq / g by the titration method.

Next, the separator was sandwiched between a negative electrode having a width equal to that of Example 1 and a positive electrode similar to that of Example 1, and wound in a vortex to form an electrode group. The electrode group and the alkaline electrolyte solution of about 7 grams containing KOH and LiOH in a molar ratio of 17: 1 are stored in a cylindrical container with a bottom, and have the structure shown in FIG. 1 above. ) Is 2.2Ah and the size A cylindrical Ni-MH rechargeable battery was assembled.

The alkaline electrolyte equivalent (Xmeq / Ah) per battery capacity of 1 Ah of the electrolyte solution contained in the container of the secondary battery was obtained from the above formula (I) (Zo = 7N, V = 3,0ml, Co = 2,2Ah), 9.55. Obtained X is represented by said Formula (1), {0.409- (X / 55)} Y Substituted in (0.636+ (2X / 55)), the following formula (H) was obtained.

The ion exchange amount (Y) per 1 Ah of battery capacity of the separator was calculated from the above formula (II) (Yo = 0.8 meq / g, W = 0.743 g, Co = 2.2 Ah) and 0.27 meq / Ah.

Example 44

A nickel-hydrogen secondary battery similar to Example 43 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 1.5 (meq / g) and the weight (W) was 0.733 g. Ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery (Y). It was 0.50 meq / Ah when calculated | required from said Formula (II).

Example 45

A nickel-hydrogen secondary battery similar to Example 43 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 1.9 (meq / g) and the weight (W) was 0.753 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was found to be 0.65 meq / Ah from the above formula (II).

Example 46

A nickel-sinter secondary battery similar to Example 43 was assembled except that the amount of potassium ion exchange (Yo) measured by the separator titration method was 2.5 (meq / g) and the weight (W) was 0.730 g. It was 0.83 meq / Ah when ion exchange amount (Y) per battery capacity lAh of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 43

A nickel-hydrogen secondary battery similar to Example 43 was assembled except for a cut having a potassium ion exchange amount (Yo) of 0.2 (meq / g) and a weight (W) of 0.770 g measured by a separator titration method. It was 0.07 meq / Ah when the ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was calculated | required from said Formula (II).

Comparative Example 44

A nickel-hydrogen secondary battery similar to Example 43 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 0.4 (meq / g) and the weight (W) was 0.770 g. The ion exchange amount (Y) per battery capacity lAh of the separator of the obtained secondary battery was found to be 0.14 meq / Ah from the above formula (II).

Comparative Example 45

A nickel-hydrogen secondary battery similar to Example 43 was assembled except that the potassium ion exchange amount (Yo) measured by the separator titration method was 3.1 (meq / g) and the weight (W) was 0.745 g. The ion exchange amount (Y) per battery capacity of 1 Ah of the separator of the obtained secondary battery was 1.05 meq / Ah, as determined from the formula (II).

The secondary batteries of the obtained Examples 43 to 46 and Comparative Examples 43 to 45 were obtained in the same manner as described above, and the charge and discharge cycle life of the batteries were obtained, and the results are shown in FIG.

As apparent from FIG. 9, the ion exchange amount (Y) (meq / Ah) is represented by the formula (1); {0.409- (X / 55)} Y Secondary Batteries of Examples 43 to 46 with Separators Satisfying {0.636+ (2X / 55)} An Example with Separators with Ion Exchange Amount (Y) (meq / Ah) out of Equation (1) It can be seen that the charge and discharge cycle life is longer than that of the 43-45 secondary batteries.

It can be seen from Examples 39 to 46 that the nickel-hydrogen secondary battery having a separator that satisfies the above formula (l) despite the battery capacity and battery size can improve cycle life.

Example 50

[Production of past minus play]

A hydrogen absorbing alloy having a composition of LmNi ₄ oCoo ₄ Mn and ₃ Alo ₃ was produced by a high frequency furnace using commercially available lantern-rich Mischmetal (Lm) and Ni, Co, Mn, and A1. The hydrogen absorbing alloy was milled and passed through a 200-mesh sieve. 0.5 parts by weight of sodium polyacrylate, 0.125 parts by weight of carboxymethyl cellulose (CMC), 2.5 parts by weight of polytetrafluoroethylene dispersion (1.5% by weight, 60% by weight of solid), and carbon powder as the conductive powder The paste was prepared by mixing 1.0 weight part with 50 weight part of water. The paste was applied to punched metal, dried, and pressed to form a paste-type negative electrode.

[Production of paste type positive play]

To a mixed powder consisting of 90 parts by weight of nickel hydroxide powder and 10 parts by weight of cobalt oxide powder, 0.3 parts by weight of carboxymethyl cellulose and polytetrafluoroerylene (specific weight 1.5, solid content of 60% by weight) were converted into solids with respect to the nickel hydroxide powder. 0,5 weight part was added and 45 weight part of blunt water was added to these, and the paste was prepared by stirring. Subsequently, this paste was filled into a nickel-plated metal porous body, dried, rolled and rolled to produce a paste type positive electrode.

[Production of Separator]

Polypropylene resin with no light stabilizer was produced using a span bond method to produce a nonwoven fabric having a scale of 50 g / m ² and a thickness of 0.20 mm. After immersing the nonwoven fabric in an aqueous solution of acrylic acid, the self-irradiating line was irradiated to graf the copolymer of acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to impart a carboxyl group as part of the polypropylene fiber contained in the nonwoven fabric as an ion exchange group. The ion exchange amount of the nonwoven fabric (graft copolymerization ratio of acrylic acid monomer) was measured by the above titration method, and the ion exchange amount was 0.lmeq / g. The nonwoven fabric was immersed in an alkaline aqueous solution of 0.7% potassium hydroxide and 0.1% lithium hydroxide, washed with water and dried to react the carboxyl group of the acrylic acid graft copolymerized with the alkali metal ion of the alkaline aqueous solution to form a salt. The separator which consists of a nonwoven fabric containing the polypropylene fiber which has a carboxyl group in the form of a salt by the alkaline aqueous solution of the same kind and concentration ratio as electrolyte solution was produced.

Next, the separator was sandwiched between the negative electrode and the plus electrode and wound in a vortex to form an electrode group. An electrolytic solution composed of such an electrode group, 7N potassium hydroxide and 1N lithium hydroxide was housed in a bottomed cylindrical container, and AA size long-distance nickel-hydrogen secondary batteries having the structure shown in FIG.

Example 51

A nickel-hydrogen secondary battery similar to Example 50 was assembled except using the separator described below.

That is, the same nonwoven fabric as in Example 50 was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet light to graf the copolymer of acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to impart a carboxyl group as part of the polypropylene fiber incorporated into the nonwoven fabric as an ion exchange group. It was 0.2 meq / g when the ion exchange amount (graft copolymerization ratio of acrylic acid monomer) of the said nonwoven fabric was measured by the said titration method. By treating the nonwoven fabric with the same alkaline aqueous solution as in Example 50, a separator made of a nonwoven fabric containing polypropylene fiber having a carboxyl group in the form of a salt with an alkaline aqueous solution having the same type and concentration ratio as the electrolyte was produced.

Example 52

A nickel-hydrogen secondary battery similar to Example 50 was assembled except using the separator described below.

That is, the same nonwoven fabric as in Example 50 was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet light to graf the copolymer of acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to impart a carboxyl group as part of the polypropylene fiber contained in the nonwoven fabric as an ion exchange group. It was 0.8 meq / g when the ion exchange amount (grafting copolymerization ratio of the acrylic acid monomer) of the said nonwoven fabric was measured by the said titration method. By treating the nonwoven fabric with the same alkaline aqueous solution as in Example 50, a separator made of a nonwoven fabric containing a polypropylene fiber having a carboxyl group in the form of a salt with the above-mentioned electrolyte solution and an alkaline aqueous solution having the same distillation and concentration ratio was produced.

Example 53

A nickel-hydrogen secondary battery similar to Example 50 was assembled except using the separator described below.

That is, the same nonwoven fabric as in Example 50 was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet light to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to impart a carboxyl group as part of the polypropylene fiber contained in the nonwoven fabric as an ion exchange group. The ion exchange amount of the nonwoven fabric (graft copolymerization ratio of the acrylic acid monomer) was measured by the above titration method, and the ion exchange amount was 1.5 meq / g. The electrolytic solution was subjected to the same alkaline aqueous solution treatment as in Example 50. The separator which consists of a nonwoven fabric containing the polypropylene fiber which has a carboxyl group in the form of a salt by the alkaline aqueous solution of the same kind and concentration ratio was produced.

Example 54

A Nigels small secondary battery was assembled in the same manner as in Example 50 except that the separator described below was used.

That is, the same nonwoven fabric as in Example 50 was immersed in an aqueous solution of acrylic acid, and then irradiated with ultraviolet light to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to give a portion of the polypropylene fiber contained in the nonwoven fabric as a carboxyl group as an ion exchanger. The ion exchange amount of the nonwoven fabric (graft copolymerization ratio of the acrylic acid monomer) was measured by the above titration method, and the ion exchange amount was 2.0 meq / g. By treating the nonwoven fabric with the same alkaline aqueous solution as in Example 50, a separator made of a nonwoven fabric containing a polypropylene fiber having a carboxyl group in the form of a salt with an alkaline aqueous solution having the same type and concentration ratio as the electrolyte was produced.

Example 55

A nickel-metal hydride secondary battery similar to Example 50 was assembled except using the separator described below.

That is, the same nonwoven fabric as in Example 50 was immersed in an aqueous acrylic acid solution, and then irradiated with ultraviolet light to graf the copolymer of acrylic acid. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to impart a carboxyl group as an ion exchange group to a part of the polypropylene fibers incorporated into the nonwoven fabric. It was 2.5 meq / g when the ion-exchange amount (grafting copolymerization ratio of the acrylate monomer) of the said nonwoven fabric was measured by the said titration method. By treating the nonwoven fabric with the same alkaline aqueous solution as in Example 50, a separator made of a nonwoven fabric containing polypropylene fiber having a carboxyl group in the form of a salt with an alkaline aqueous solution having the same type and concentration ratio as the electrolyte was produced.

[Comparative Example 50]

The above-mentioned alkaline aqueous solution treatment was not carried out to the separator. The AA Nitrogen hydrogen secondary battery of size AA having the structure shown in FIG. 1 was assembled by the same method as in Example 50.

Comparative Example 51

An AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. 1 was assembled in the same manner as in Example 51 except that the separator was not subjected to the alkaline aqueous solution treatment.

Comparative Example 52

The above-mentioned alkaline aqueous solution treatment was not carried out to the separator. As a result, an AA-size cylindrical Nigel Sousse secondary battery having the structure shown in Fig. 1 was assembled by the same method as in Example 52.

Comparative Example 53

An AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. 1 was assembled in the same manner as in Example 53 except that the separator was not subjected to the alkaline aqueous solution treatment.

[Comparative Example 54]

An AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. 1 was assembled in the same manner as in Example 54 except that the separator was not subjected to the alkaline aqueous solution treatment.

Comparative Example 55

An AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. 1 was assembled in the same manner as in Example 55 except that the separator was not subjected to the alkaline aqueous solution treatment.

The secondary batteries of Examples 50-55 and Comparative Examples 50-55 obtained were charged and discharged at 150C at 1CmA and then discharged at 1CmA until the battery voltage reached 1.0V. The discharge capacity was calculated from the time until the battery voltage reached 1.0V. The results are shown in FIGS. 10 and 11. The discharge capacity ratio at the longitudinal side in FIG. 10 indicates the discharge capacity in subsequent cycles of the secondary batteries of Examples 50, 51, 53, 54, and 55, with the discharge capacity in the first cycle of Example 52 being 100. FIG. . The cycle number ratio on the horizontal axis in FIG. 10 is cycle 100 in which the discharge capacity of the secondary battery of Example 52 reaches 80% of the discharge capacity of the first cycle, and the cycle number of Examples 50, 51, 53, 54, 55 is used. It is shown. In addition, the discharge capacity ratio of the vertical axis | shaft of FIG. 11 has shown the discharge capacity in the subsequent cycle of the secondary battery of Comparative Examples 50-55 making 100 the discharge capacity of the 1-cycle material of Example 52. The cycle number ratio on the horizontal axis in FIG. 1L is the number of cycles in which the discharge capacity of the secondary battery of Example 52 reached 80% of the discharge capacity of the first cycle, and the cycle number of Comparative Examples 50 to 55 is shown.

It can be seen from the relationship between FIGS. 10 and 11 that the secondary batteries of Examples 50 to 55 of the present invention have a longer charge / discharge cycle life than the secondary batteries of Comparative Examples 50 to 55. This is because the sheet-like article containing the polyolefin-based synthetic resin fibers having a carboxyl group is treated with an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte, so that the carboxyl group in the form of a salt is used as the separator. In particular, it can be seen that the charge and discharge cycle life of the secondary batteries of Examples 51 to 54 provided with a separator having an ion exchange amount of 0.2 to 2.0 rneq / g was longer than that of Examples 50 and 55.

[Comparative Example 56]

A nickel-hydrogen secondary battery similar to Example 50 was assembled except using the separator described below.

The same nonwoven fabric as in Example 50 was immersed in an aqueous solution of acrylic acid and irradiated with ultraviolet light to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and then dried to impart a carboxyl group as part of the polypropylene fiber contained in the nonwoven fabric as an ion exchange group. It was 0.8 meq / g when the ion exchange amount (grafting copolymerization ratio of the acrylic acid monomer) of the said nonwoven fabric was measured by the said titration method. The nonwoven fabric was immersed in an alkaline aqueous solution composed of 0.5% potassium hydroxide and 0.5% lithium hydroxide, washed with water, and dried to react the carboxyl group of acrylic acid graft copolymerized with the alkali metal ion of the alkaline aqueous solution to form a carboxyl group. Made.

The cycle characteristics test was carried out on the secondary battery of Comparative Example 56 obtained by the same method as described above, and the discharge capacity of cycle l was the same as that of Example 52, but the discharge capacity of the secondary battery of Example 52 was the first cycle. When the number of cycles reached 80% of the discharge capacity was 100, the number of cycles when the discharge capacity of the secondary battery of Comparative Example 56 reached 80% of the discharge capacity of the first cycle was 80, and the comparative example 56 was cycled. The life was short. The cycle life of the secondary battery of Comparative Example 56 is short because the treatment was performed with an alkaline aqueous solution having the same type as the alkaline electrolyte.

Example 70

[Production of past minus play]

Using commercially available lantern-rich mitsch metal (Mm) and Ni, Co, Mn, A1 by MmNi ₃ . ₆ Coo. ₈ Mno, ₄ Alo. _The hydrogen storage alloy which consists of ₂ compositions was produced. The hydrogen absorbing alloy was milled and passed through a 200-mesh sieve. 0.4 parts by weight of sodium polyacrylate, 0.1 parts by weight of carboxymethyl cellulose (CMC), 1.5 parts by weight of polytetrafluoroethylene dispersion (specific gravity 1.5, solid content of 60 wt%) and conductive material based on 100 parts by weight of the hydrogen storage alloy powder thus obtained. The paste was prepared by mixing 0.8 parts by weight of carbon powder with 55 parts by weight of water. The paste was applied to punched metal, dried, and pressed to form a paste-type negative electrode.

[Production of paste type positive play]

To a mixed powder consisting of 90 parts by weight of nickel hydroxide powder and 10 parts by weight of cobalt hydroxide powder, 0.3 parts by weight of carboxymethyl cellulose and polytetrafluoroethylene suspension (1.5 parts by weight, 60 parts by weight of solids) were converted into solids with respect to the nickel hydroxide powder. 1,0 weight part was added, 30 weight part of blunt water was added to these, and the paste was prepared by stirring. Subsequently, the paste was filled into a nickel plated fiber substrate, and then the paste was applied to both surfaces thereof, dried, and then rolled and rolled to prepare a paste type positive electrode.

[Production of Separator]

The polypropylene resin was made of a nonwoven fabric having a length of 50 g / m ² and a thickness of Q.20 mm made of a long fiber having an average diameter of 10 μm using a span bond method. The nonwoven fabric was immersed in an aqueous acrylic acid solution and irradiated with ultraviolet rays to graft co-polymerize the acrylic acid monomer, and each nonwoven fabric was washed to remove unreacted acrylic acid and dried to form a nonwoven fabric mainly composed of polypropylene fibers having a COOH group as an ion exchanger. A separator was prepared in which the ion exchange amount of potassium by the titration method described above was 0.8 meq / g.

The above formula (1), (0.05X + 0.05) ≦ Y ≦ 2. According to Q, the range of potassium ion exchange amount (Y) required for excellent self-discharge characteristics and large current discharge characteristics at high temperature storage when the average diameter (X) of all the fibers constituting the separator is 10 μm is 0.55 ≦ Y≤2.0. Thus, the obtained separator is formula (1) and formula (2) in which the mean diameter (X) and potassium ion exchange amount (Y) are described above; 1≤X≤20 is satisfied at the same time.

Next, the separator was sandwiched between the negative electrode and the plus electrode and wound in a vortex to form an electrode group. An electrolytic solution composed of such an electrode group and 0.1 N of LiOH and 7.9 N of KOH was housed in a bottomed cylindrical container, whereby an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. 1 was assembled.

Example 71

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed solution composed of 0.3N LiOH and 7.7N KOH was used as the alkaline electrolyte.

Example 72

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed liquid composed of LiOH of Q.5N and KOH of 7.5N was used as the alkaline electrolyte.

Example 73

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed liquid composed of 1.0 N LiOH and 7.0 N KOH was used as the alkaline electrolyte.

Example 74

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed liquid composed of 1.3N LiOH and 6.7N KOH was used as the alkaline electrolyte.

Example 75

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed liquid composed of 1.5N LiOH and 6.5N KOH was used as the alkaline electrolyte.

Example 76

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed liquid composed of 0.5N NaOH and 7.5N KOH was used as the alkaline electrolyte.

Example 77

The same carboxyl group secondary battery as in Example 70 was assembled except that a mixture consisting of 1.0 N NaOH and 7.0 N KOH was used as the alkaline electrolyte.

Example 78

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed solution composed of 2.0N NaOH and 6.0N KOH was used as the alkaline electrolyte.

Example 79

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a mixed solution composed of 4.0N NaOH and 4.0N KOH was used as the alkaline electrolyte.

Example 80

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that the mixture consisting of 5.0 N NaOH and 3.0 N KOH was used as the alkaline electrolyte.

Example 81

A nickel-metal hydride secondary battery similar to Example 70 was assembled except that a mixed solution composed of 6.0N NaOH and 2.0N KOH was used as the alkaline electrolyte.

[Comparative Example 70]

A nickel-hydrogen secondary battery similar to Example 70 was assembled except that a 8.0N KOH aqueous solution was used as the alkaline electrolyte.

[Comparative Example 7l]

A sheath type with a sheath type coated with polyethylene resin on the surface of the core material made of polypropylene fiber, and an ethylene vinyl alcohol copolymer resin coated on the surface of the core material made of polypropylene fiber with a composite fiber having an average diameter of 15 µm. The separator which had a structure, mixed 15 micrometers of average diameters, and produced the separator which consists of a nonwoven fabric of 50 g / m <^2> and 0.20 mm of thickness by the dry method was produced. It was Omeq / g when the potassium ion exchange amount of the obtained separator was measured by the said titration method.

Next, the separator was sandwiched between the same negative electrode and the positive electrode as in Example 70 and wound in a vortex to form an electrode group. An electrolytic solution composed of such an electrode group and 8.0 N KOH was housed in a bottomed cylindrical container, and an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. 1 was assembled.

The secondary batteries of Examples 70 to 81 and Comparative Examples 70 and 71 obtained were charged and discharged at 150C at 1CmA in an atmosphere of 20 ° C, and then discharged and discharged at 1CmA until the battery voltage reached 1.0V three times. did. Thereafter, the mixture was left at 20 ° C for 2 hours while charging 1CmA at 150%, and then stored in a 40 ° C thermostat for 14 days. After storage, the mixture was left at 20 ° C. for 2 hours, discharged at 1 CmA until the battery voltage reached 1.0 V, and the discharge capacity (remaining capacity) was measured. In a constant temperature bath at 40 ℃ the discharge capacity when charged at 150% for 14 days 1CmA prior to storage, and discharged to a battery voltage of 1.0V with a 1CmA C _'0, and the constant temperature bath 14 days of the discharge capacity after the storage at 40 ℃ When the residual capacity (C ' _R ) was taken as, the capacity remaining rate was obtained from the following equation. The self-discharge characteristics were determined from this capacity retention rate.

12 shows the relationship between the lithium hydroxide concentration in the electrolytic solution and the capacity retention in the secondary batteries of Examples 70 to 75 and Comparative Examples 70 and 71. 13 shows the relationship between the sodium hydroxide concentration in the electrolytic solution and the capacity retention in the secondary batteries of Examples 76 to 81 and Comparative Examples 70 and 71.

As is clear from FIGS. 12 and 13, it can be seen that the secondary batteries of Examples 70 to 81 can suppress self discharge at high temperature storage at 40 ° C as compared with those of Comparative Examples 70 and 71. In this regard, it is important to use an alkali electrolyte solution containing at least one of lithium hydroxide and sodium hydroxide at the same time by using a separator that satisfies the above two equations to improve the self-discharge characteristics during high temperature storage of the nickel-hydrogen secondary battery. It can be seen that.

Example 82

Polypropylene fiber is made from polypropylene resin by melt-blowing method, and the average weave (X) is 1 time. A scale of 50g / m ² and a thickness of 0.2mrn are made. This nonwoven fabric is immersed in acrylic acid solution and then UV The acrylic acid monomer was graft-copolymerized by irradiation. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to prepare a separator having a potassium ion exchange amount of O.lmeq / g consisting of a nonwoven fabric mainly composed of polypropylene fiber having a COOH group as an ion exchanger. In addition, the ion-exchange amount of potassium was measured by the said titration method.

Next, the separator was sandwiched between the same negative electrode as in Example 70 and the plus electrode as in Example 70, and wound in a vortex to form an electrode group. An electrolytic solution composed of such an electrode group and 7N KOH and 1N LiOH was housed in a bottomed cylindrical container to assemble an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG.

Example 83

The polypropylene fiber was made of polypropylene fiber having an average diameter (X) of 1 μm from the polypropylene resin, and a nonwoven fabric having a scale of 50 g / m ² and a thickness of 0.2 mm. The nonwoven fabric was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to prepare a separator having a potassium ion exchange amount of 1.0 meq / g based on the above polypropylene fiber mainly having a polypropylene fiber having a COOH group as an ion exchanger. . The same Nigel hydrogen secondary battery as in Example 82 was assembled except using this separator.

Example 84

A nonwoven fabric 156 of polypropylene fiber having an average diameter (X) of 1 sheet and a scale of 50 g / m ² and a thickness of 0.2 mm was made from the polypropylene resin by melt blow method. The nonwoven fabric was immersed in an aqueous acrylic acid solution and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer. The nonwoven fabric is washed to remove unreacted acrylic acid and dried to form a nonwoven fabric composed mainly of polypropylene fibers having an ion-exchanged COOH group, wherein the ion exchange amount of potassium by the titration method is 2.0 meq / g. The separator was produced. A nickel-hydrogen secondary battery similar to Example 82 was fabricated except that this separator was used.

According to the above formula (1), when the average diameter (X) of all the fibers constituting the separator is 1 µm, the amount of potassium ion exchange (Y) necessary to improve the self-discharge characteristics and the large current discharge characteristics at high temperature storage is obtained. The range is 0.1 ≦ Y ≦ 2.0. Therefore, in the separators of secondary batteries obtained in Examples 82 to 84, the average diameter (X) and the amount of potassium ion exchange (Y) satisfy the above formulas (1) and (2).

Example 85

A fiber made of copolymerized resin obtained by copolymerizing butene with polypropylene resin was prepared, and 50% by weight of this fiber and 50% by weight of polypropylene resin fiber were mixed, and the average diameter (X) was 20 μm by a wet method, and the scale was 50 g / m ^2. And a non-woven fabric having a thickness of 0.2 mm. The nonwoven fabric was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to form a nonwoven fabric mainly composed of a polypropylene fiber having a COOH group and a copolymer resin fiber having a COOH group as an ion exchanger, and the ion exchange amount of potassium by the above titration method was 1.5. The separator which is meq / g was produced.

A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

Example 86

A fiber made of copolymerized resin obtained by copolymerizing butene copolymerized with polypropylene resin is mixed. 50% by weight of the fiber and 50% by weight of polypropylene resin fiber are mixed, and the average diameter (X) is 20 占 퐉 and the scale amount is 50 g / A nonwoven fabric of m ² and thickness of 0.2 mm was produced. The nonwoven fabric was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer. The nonwoven fabric is washed to remove unreacted acrylic acid and dried to form a nonwoven fabric composed mainly of polypropylene fiber having a COOH group and a copolymer resin fiber having a COOH group as an ion exchanger, and ion exchange of potassium by the above titration method. The amount produced the separator in 1.5 meq / g. A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

Example 87

A fiber made of copolymerized resin obtained by copolymerizing butene with polypropylene resin was prepared. The fiber was mixed with 50% by weight of polypropylene resin and 50% by weight of polypropylene resin fiber, and the average diameter (X) was 20 μm by a wet method, and the scale was 50 g / m ^2. And a non-woven fabric having a thickness of 0.2 mm was produced. The nonwoven fabric was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet light to graf the copolymer of acrylic acid monomer. The nonwoven fabric is washed to remove unreacted acrylic acid and dried to form a nonwoven fabric composed mainly of polypropylene fibers having a COOH group and copolymer resin fibers having a COOH group, and ion exchange amount of potassium by the titration method described above. A separator of 2.0 meq / g was produced. A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

According to the above formula (1), when the average diameter (X) of all the fibers constituting the separator is 20 µm, the amount of potassium ion exchange amount (Y) necessary to improve the self-discharge characteristics and the large current discharge characteristics at high temperature storage is obtained. The range is 1.0 ≦ Y ≦ 2.0. Therefore, in the separator of secondary batteries obtained in Examples 85 to 87, the average diameter (X) and the amount of potassium ion exchange (Y) satisfy the above formulas (1) and (2).

[Comparative Example 72]

A polypropylene fiber with an average diameter (X) of 1 μm is formed from the polypropylene resin by a melt blow method, and a nonwoven fabric having a scale of 50 g / m ² and a thickness of 0.2 mm is made, and the nonwoven fabric is immersed in an acrylic acid aqueous solution and then subjected to ultraviolet rays. The acrylic acid monomer was graft-copolymerized by irradiation. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to prepare a separator having a polypropylene fiber mainly composed of a polypropylene fiber having a COOH group as an ion exchanger, wherein the ion exchange amount of potassium by the titration method was 0.05 meq / g. did. A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

Comparative Example 73

Polypropylene fiber of average diameter (X) of 1μm is made from polypropylene resin by melt blow method, and the scale is 50g / m ² and the thickness of 0.2mm is made of nonwoven fabric, and this nonwoven fabric is immersed in acrylic acid aqueous solution The acrylic acid monomer was graft-copolymerized by irradiation. The nonwoven fabric is washed to remove unreacted acrylic acid and dried to form a nonwoven fabric composed mainly of polypropylene fiber having a COOH group as an ion exchanger, and the ion exchange amount of potassium by the titration method is 2.5 meq / g. The use of such a separator object was the same as that of Example 82, in which a nickel-hydrogen secondary battery was assembled.

[Comparative Example 74]

A fiber made of a copolymerized resin obtained by copolymerizing butene copolymerized with polypropylene resin was prepared, and 50% by weight of this fiber and 50% by weight of polypropylene resin fiber were mixed, and the average diameter (X) was 20 μm by a wet method, and the scale was 50 g / m ^2. And a nonwoven fabric having a thickness of 0.2 mm was produced. The nonwoven fabric was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet light to graf the copolymer of acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to form a nonwoven fabric mainly composed of a polypropylene fiber having a COOH group and a copolymer resin fiber having a COOH group as an ion exchanger, and the ion exchange amount of potassium by the above titration method was 0.6 The separator which is meq / g was produced. A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

[Comparative Example 75]

A fiber made of a copolymerized resin obtained by copolymerizing butene with a polypropylene resin was prepared. The fiber was mixed with 50% by weight of polypropylene resin and 50% by weight of polypropylene resin, and the average diameter (X) was 20 μm by a wet method, and the scale was 50 g / m ^2. And a non-woven fabric having a thickness of 0.2 mm was produced. The nonwoven fabric was immersed in an acrylic acid aqueous solution and then irradiated with ultraviolet light to graf the copolymer of acrylic acid monomer. The nonwoven fabric is washed to remove unreacted acrylic acid and dried to form a nonwoven fabric composed mainly of polypropylene fibers having a COOH group and copolymer resin fibers having a COOH group, and ion exchange amount of potassium by the titration method described above. A separator of 2.5 meq / g was produced. A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

[Comparative Example 76]

A polypropylene fiber with an average diameter (X) of 0,5 µm was formed from a polypropylene resin by a melt blow method, and a nonwoven fabric having a scale of 50 g / m ² and a thickness of 0.2 mm was made, and the nonwoven fabric was immersed in an acrylic acid aqueous solution. After irradiation with ultraviolet rays, the acrylic acid monomer was graft-copolymerized. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to form a nonwoven fabric mainly composed of polypropylene fibers having a COOH group as an ion exchanger, and a separator having a potassium ion exchange amount of 1.Omeq / g by the titration method described above. Made. Such a separator could not be produced from this separator because the separator was broken when it was sandwiched between the plus and minus electrodes due to lack of strength and was turned around.

[Comparative Example 77]

A fiber made of a copolymerized resin copolymerized with butene is made of polypropylene resin, and 50% by weight of this fiber and 50% by weight of polypropylene resin fiber are mixed, and the average diameter (X) is 25 탆 by a wet method, and the scale is 50 g / m ^2. And a nonwoven fabric having a thickness of 0.2rnm was produced. After immersing this nonwoven fabric in aqueous acrylic acid solution, the self-irradiated ray was irradiated to graf the copolymer of acrylic acid monomer. The nonwoven fabric is washed to remove unreacted acrylic acid and dried to form a nonwoven fabric composed mainly of polypropylene fibers having a COOH group and copolymerized resin fibers having a COOH group as ion exchange groups, and ion exchange of potassium by the above titration method. The separator whose quantity is 1.0 meq / g was produced. A nickel-hydrogen secondary battery similar to Example 82 was assembled except that the separator was used.

With respect to the secondary batteries obtained in Examples 82 to 87 and Comparative Examples 72 and 74, the self-discharge characteristics at 40 ° C. were measured by the same method as that for the secondary batteries of Examples 70 to 81 described above. Are shown in FIGS.

As apparent from FIG. 14, it can be seen that the secondary batteries of Examples 82 to 84 of the present invention have improved self-discharge characteristics at high temperature storage compared with the secondary batteries of Comparative Example 72. As apparent from FIG. 15, it can be seen that the secondary batteries of Examples 85 to 87 of the present invention have improved self-discharge characteristics at high temperature storage compared with the secondary batteries of Comparative Example 74.

In addition, the insulation failure occurrence rate after electrode group production was measured for the secondary batteries of Examples 82 to 87 and Comparative Example 77. Measurement of the insulation failure after electrode group production was performed by measuring the insulation resistance value when the voltage of 500V was applied with the insulation ohmmeter immediately after 100 electrode groups were produced. The results are shown in Table 12 below.

As apparent from Table 12, it can be seen that the secondary batteries of Examples 82 to 87 of the present invention can avoid the occurrence of poor insulation resistance when fabricating the electrode group.

This is because the separators used in Examples 82 to 87 are dense, so that a short between the positive and negative poles at the time of winding can be prevented.

In addition, the secondary batteries of Examples 82 to 87 and Comparative Examples 73 and 75 were subjected to 150% heavy discharge at 0.3CmA and then discharged at 2CmA until the battery voltage reached 1.0V. Evaluated. The discharge capacity was calculated from the time until the battery voltage reached 1.0 V at 2 CmA discharge.

The results of the large current discharge characteristic test are shown in Tables 13 and 14 below. In Table 13, the discharge capacities of Examples 82 to 84 and Comparative Examples 65 to 73 were shown as the discharge capacities of Example 82. In Table 14, the discharge capacities of Examples 85 to 100 were shown, and the discharge capacities of Examples 86 to 87 and Comparative Example 75 were shown.

As apparent from Table 13, it can be seen that the secondary batteries of Examples 82 to 84 of the present invention are superior in large current discharge characteristics as compared with Comparative Example 73. As apparent from Table 14, it can be seen that the secondary batteries of Examples 85 to 87 of the present invention are superior in current discharge characteristics as compared with Comparative Example 75. This is because alkali metal ions in the electrolytic solution are immobilized on the separator and the operating voltage during the large current discharge is lowered because the ion exchange amount of the separator used in the secondary batteries of Comparative Examples 73 and 75 is high.

Example 88

Polypropylene resin is made of long fiber with 10μm fiber diameter by span bond method and scale amount is 50g / m And a non-woven fabric having a thickness of 0.20 mm. Subsequently, the first roll having the smooth surface and the second roll having a plurality of pinpoint irregularities formed on the surface thereof are disposed to face each other, and these rolls are rotated in opposite directions, and these rolls are heated to 130 ° C. The nonwoven fabric was passed through the liver to pressurize the convex portions of the first roll and the second roll, and heat-sealed to perform embossing. By this embossing, a plurality of circular recesses are formed on the sheet-like article, and a filmed portion (film portion) is formed on the bottom surface (emboss surface) of the recess. At the same time, the part of the said 2nd surface of the said sheet-like thing corresponding to the said recessed part also turns into a filmed surface. The area ratio of the said film part was made into 16% with respect to the 2nd surface of the said nonwoven fabric. Subsequently, the latter ultraviolet ray was irradiated with the nonwoven fabric immersed in an acrylic acid aqueous solution to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to prepare a separator.

The obtained separator is a nonwoven fabric mainly composed of polypropylene fibers having a COOH group and polypropylene fibers not having a COOH group as an ion exchange group, and the embossed first side is hydrophilized, and a second side opposite to the first side. Areas other than the film part in surface were hydrophilized, and the said film part remained as a hydrophobic part. The minority part of the said 2nd surface was 16% of area ratio. Moreover, the graft copolymerization ratio of the acrylic acid monomer was measured with respect to the hydrophilic part of the said separator by the titration method mentioned above. As a result, the ion exchange amount of potassium was 0.8 meq / g. Equation (1) is 0.55 ≦ Y ≦ 2.0 when the average diameter of all the fibers constituting the separator is 10 μm. Therefore, the separator satisfies Equation (1) and Equation (2) at the same time. Next, the separator was sandwiched between the negative and positive poles of Example 70 with the hydrophilic and hydrophobic portions of the separator facing the negative pole, and wound in a vortex to form an electrode group.

An electrolytic solution composed of such an electrode group and 0.1 N LiOH and 7.9 N KOH was housed in a bottomed cylindrical container, whereby an AA size cylindrical nickel hydride secondary battery having the structure shown in FIG. 1 was assembled.

Example 89

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed liquid composed of 0.3N LiOH and 7.7N KOH was used as the alkaline electrolyte.

Example 90

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 0.5 N LiOH and 7.5 N KOH was used as the alkaline electrolyte.

Example 91

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 1.0 N LiOH and 7.0 N KOH was used as the alkaline electrolyte.

Example 92

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 1.3N of LiOH and 6.7N of KOH was used as the alkaline electrolyte.

Example 93

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 1.5N LiOH and 6.5N KOH was used as the alkaline electrolyte.

Example 94

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed liquid composed of 0.5N NaOH and 7.5N KOH was used as the alkaline electrolyte.

Example 95

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 1.0 N NaOH and 7.0 N KOH was used as the alkaline electrolyte.

Example 96

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 2.0N NaOH and 6.0N KOH was used as the alkaline electrolyte.

Example 97

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed liquid composed of 4.0 N NaOH and 4.0 N KOH was used as the alkaline electrolyte.

Example 98

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution composed of 5.0 N NaOH and 3.0 N KOH was used as the alkaline electrolyte.

Example 99

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that a mixed solution of 6.0 N NaOH and 2.0 N KOHOH was used as the alkaline electrolyte.

[Comparative Example 78]

A nickel-hydrogen secondary battery similar to Example 88 was assembled except that an aqueous 8.0N KOH aqueous solution was used as the alkaline electrolyte.

With respect to the secondary batteries of Examples 88 to 99 and Comparative Example 78 obtained, the self-discharge characteristics at 40 ° C. were measured by the same method as that described for the secondary batteries of Examples 70 to 81 described above. 16 to 17 are shown. 16 and 17 show the results of Comparative Example 71 together.

16 shows the relationship between the lithium hydroxide concentration in the electrolyte solution and the capacity remaining rate in the secondary batteries of Examples 88 to 93 and Comparative Examples 71 and 78. FIG. 17 shows the relationship between the sodium hydroxide concentration in the electrolyte solution and the capacity retention rate in the secondary batteries of Examples 94 to 99 and Comparative Examples 71 and 78. FIG.

As apparent from FIG. 16, it can be seen that the secondary batteries of Examples 88 to 93 can suppress self discharge at high temperature storage at 40 ° C as compared with those of Comparative Examples 71 and 78. As apparent from FIG. 17, it can be seen that the secondary batteries of Examples 94 to 99 can suppress self discharge at high temperature storage at 40 占 폚 as compared with the secondary batteries of Comparative Examples 71 and 78. Moreover, by comparing FIG. 12 and FIG. 16, FIG. 13, and FIG. 17, it is a sheet-like thing which satisfy | fills Formula (1) and Formula (2), and a 1st surface is hydrophilic and a 2nd surface is a hydrophilic part and a hydrophobic part. A nickel hydride secondary battery having a separator having a separator, wherein the separator is disposed between the positive electrode and the negative electrode so that the second surface faces the negative electrode, and the ion exchange amount of both surfaces is equal, and (1) It can be seen that the self discharge characteristic at the time of high temperature storage can be improved compared with the nickel-hydrogen secondary battery provided with the separator which satisfy | fills Formula and said Formula (2).

In addition, the withstand voltage of the secondary batteries of Examples 88 to 99 and Comparative Examples 70 and 71 obtained were measured. The measurement of the battery internal pressure was carried out by storing the batteries of Examples 88 to 99 and Comparative Examples 70 and 71 in the vessel of the pressure measuring device shown in FIG.

Each battery pressure measuring device includes a battery case including a case body 3l made of acrylic resin and a cap 32. The core 33 of the case body 31 is provided with a space 33 having the same inner diameter and height as the metal container of the AA size battery. The secondary battery C is accommodated in the space 33. The secondary battery C is open without a sealing plate attached to an upper end of a cylindrical container having a bottom.

On the case body 31, the cap 32 is hermetically fixed by bolts 36 and nuts 37 through packings 34 and O-rings 35.

A pressure detector 38 is attached to the cap 32. The minus pole lead 39 from the minus pole and the plus pole lead 40 from the plus pole are drawn past between the packing 34 and the O-ring 35.

By using such a withstand voltage measurement device, the maximum battery withstand voltage when the secondary batteries of Examples 88 to 99 and Comparative Examples 70 and 71 were charged at 480% with a current of 0.5 CmA was measured. It shows in 16.

As apparent from Table 15, it can be seen that the secondary batteries of Examples 88 to 93 had a lower maximum battery breakdown voltage at the time of overcharging than the secondary batteries of Comparative Examples 70 and 71. As apparent from Table 16, it can be seen that the secondary batteries of Examples 94 to 99 had a lower maximum battery breakdown voltage at the time of overcharging than the secondary batteries of Comparative Examples 70 and 71.

Therefore, it can be seen that the secondary batteries of Examples 88 to 99 can not only improve the self-discharge characteristics at the time of high temperature storage as compared with those of the Examples 70 to 81, but also suppress the withstand voltage increase during overcharging. This means that the amount of ion exchange groups in the separator is different from the front, that is, the first surface is hydrophilized by the ion exchanger, and the second surface on the opposite side of the first surface is the non-hydrophilic region and the ion exchange group non-forming region by the ion exchanger It is set as the structure which has a hydrophobic part, and it is because such a separator was sandwiched between a minus pole and a plus pole so that a said 2nd surface may face the said minus pole.

Example 100

It consists of polypropylene fiber of average diameter 3rm by melt blow method from polypropylene resin, and scale amount is 18g / m One piece of phosphorous nonwoven fabric (inner layer) was produced.

In addition, the average diameter of the composite fiber having an average diameter of 15rm was 18 g / m, having a core sheath structure in which a polyethylene resin was coated on the surface of the core made of polypropyllian fiber. Two nonwoven fabrics (surface layers) were produced. Polypropylene short fiber nonwoven fabric was sandwiched with a composite fiber nonwoven fabric, and these nonwoven fabrics were integrated by heat fusion. The average diameter of the fibers constituting the obtained nonwoven fabric of the three-layer structure was 11 µm. In addition, the graduation amount of the nonwoven fabric of the three-layer structure is 54g / m And a thickness of 0.15 tnm. The nonwoven fabric was immersed in an acrylic acid aqueous solution, and then irradiated with ultraviolet rays to graft copolymerize the acrylic acid monomer. The nonwoven fabric was washed to remove unreacted acrylic acid and dried to prepare a separator.

The separator obtained was a three-layer structure consisting of two surface layers consisting of an inner layer mainly composed of a polypropylene fiber nonwoven fabric having a COOH group as an ion exchanger, and a nonwoven fabric mainly composed of a composite fiber having a COOH group and laminated on both surfaces of the inner layer. It was to have. The average diameter of the fibers in each of the surface layers is larger than the average diameter of the fibers in the inner layers. Moreover, the potassium ion exchange amount by the said titration method of the said separator was 0.8 meq / g.

Next, the separator was sandwiched between the negative electrode as in Example 70 and the positive electrode as in Example 70, and wound in a vortex to form an electrode group. An electrolytic solution composed of such an electrode group and 7N KOH and 1N LiOH was housed in a bottomed cylindrical container to assemble an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG.

The above formula (1), (0.05X + 0.05) ≦ Y ≦ 2. According to 0, when the average diameter (X) of all the fibers constituting the separator is 11rm, the range of potassium ion exchange amount (Y) necessary for improving the high temperature storage characteristics and the large current discharge characteristics is 0.6 ≦ Y ≦ 2.0. Therefore, the separator of the secondary battery of this Example 100 satisfies the above formulas (1) and (2) (1≤X≤20).

With respect to the secondary battery of Example 100 obtained, the self-discharge characteristics at 40 ° C. were measured by the same method as that for the secondary batteries of Examples 70 to 81 described above, and the results are shown in FIG. 19.

Example 110

[Production of past minus play]

Using a commercially available lantern-rich Mischmetal (Lm) and Ni, Co, Mn, and A1, a hydrogen storage alloy made of a composition of LmNi.oCoo.Mno.Alo by a high frequency furnace was produced. The hydrogen absorbing alloy was milled and passed through a 200-mesh sieve. 0.125 parts by weight of sodium polyacrylate 0.5% by weight carboxymethyl cellulose (CMC), dispersion of polytetrafluoroethylene (specific gravity 1.5, solid content 60wt%) with respect to 100 parts by weight of the obtained alloy powder as a solid content conversion 2.5 parts by weight and a conductive material 1.0 weight part of carbon powder was mixed with 50 weight part of water, and the paste was prepared. This paste was applied to a punched metal as a conductive substrate, dried, and press-molded to produce a paste type negative electrode.

[Production of paste type positive play]

To a mixed powder consisting of 90 parts by weight of nickel hydroxide powder and 10 parts by weight of cobalt monoxide powder, a suspension of carboxymethyl cellulose 0.3 parts by weight polytetrafluoroethylene (weight ratio 1.5, solids 60% by weight) relative to the nickel hydroxide powder was converted into solids. 0.5 weight part was added, 45 weight part of distilled water was added to these, and the paste was prepared by stirring. Subsequently, this paste was filled into a nickel-plated fiber substrate as a conductive substrate, and then the paste was applied to both surfaces thereof, dried, rolled and rolled to produce a paste type positive electrode.

[Production of Separator]

45g / m scale by dry method by mixing polypropylene resin with polycarbide sheath and polypropylene fiber coated polypropylene resin Nonwoven fabric and scale 10g / m Made of nonwovens. The scale of 45g / m of these two nonwovens Irradiated with ultraviolet rays, immersed in an acrylic acid aqueous solution, and the acrylic acid monomer was graft copolymerized. The nonwoven fabric was washed to remove unreacted acrylic acid and dried. Non-woven fabric made of polyolefin-based synthetic resin fibers in which the acrylic acid monomer was graft-copolymerized, and non-woven fabric made of polyolefin-based synthetic resin fibers not subjected to the graft co-polymerization treatment were heat-bonded and laminated to a scale of 55 g / m. And a separator having a thickness of 0.20rnm. Moreover, the graft copolymerization ratio of the acrylic acid monomer of the said separator was measured by the said titration method.

As a result, the ion exchange amount of potassium was 0.8 meq / g.

Next, the separator was sandwiched between the minus poles and the plus poles such that the polyolefin synthetic resin fiber nonwoven fabric was opposed to the minus poles, and wound in a vortex to form an electrode group. An electrolytic solution composed of such an electrode group and 7N KOH and 1N LiOH was housed in a bottomed cylindrical container to assemble an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG.

Example 111

A dispersion of polytetrafluoroethylene was added to a matrix made of a binder (e.g., viscose) and released from the thin pores into a coagulation bath to obtain an unstretched polytetrafluoroethylene fiber having a fiber diameter of 15 µm.

The fiber was cut to 10 mm in length and dispersed in water at a concentration of 0.5%, and then polyacrylamide as a synthetic dispersant was added thereto to prepare a slurry. The slurry was nonwoven with a papermaking machine to obtain a sheet-like article made of polytetrafluoroethylene fiber. By heating the sheet-like article at 380 ° C. for 3 minutes, the polytetrafluoroethylene particles of the fiber bundle are fused to perform fusion between entangled fibers, and pyrolysis removal of the viscose in the sheet-like article yields a scale amount of 27.5 g / m. And a nonwoven fabric having a thickness of 0.05 mm polytetrafluoroethylene fiber.

In addition, the sheath type composite fiber and polypropylene fiber coated with polypropylpolyethylene were mixed with polyethylene resin, and the scale amount was 27.5g / m by dry method. And a nonwoven fabric having a thickness of 0.15 mm. The nonwoven fabric was immersed in ultraviolet irradiation and acrylic acid aqueous solution in the same manner as in Example l10 to graft copolymerize acrylic acid monomers. The nonwoven fabric made of polyolefin synthetic resin fiber in which the acrylic acid monomer was graft-copolymerized, and the polytetrafluoroethylene fiber nonwoven fabric were thermocompression-laminated, and the scale amount was 55 g / m. And a thickness of 0.20 mm was produced. Moreover, as a result of measuring the graft copolymerization ratio of the acrylic acid monomer of the said separator by the titration method mentioned above, the ion-exchange amount of potassium was 0.8 Ineq / g.

Next, the separator was sandwiched between the same negative electrode and the positive electrode as in Example 110 so that the polytetrafluoroethylene fiber nonwoven fabric was opposed to the negative electrode, and wound in a vortex to form an electrode group.

The electrode group was housed together with the electrolyte solution having the same composition as in Example 110 in a bottomed cylindrical container to assemble an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG.

Example 112

Scale amount 45g / m by the same method as in Example 111 , 10 g / m Two non-woven fabrics made of polytetrafluorofluoroene fibers were prepared. 45 g / m Was treated with plasma. This plasma treatment is a parallel plate electrode plasma device that uses 1.0 ounce of output of high frequency power (13MHz) using oxygen gas. The plasma treatment pressure was set at 0.1 LTorr and the plasma treatment time was 10 seconds. The nonwoven fabric subjected to the plasma treatment and the nonwoven fabric subjected to the plasma treatment were thermally compressed and laminated, and the scale amount was 55 g / m. And a separator having a thickness of 0.20 mm.

Next, the separator was sandwiched between the same negative electrode and the positive electrode as in Example 110 so that the polytetrafluoroethylene fiber nonwoven fabric was opposed to the negative electrode, and wound in a vortex to form an electrode group.

Such an electrode group was housed together with the electrolyte solution of the same composition as Example 110 in the bottomed cylindrical container, and the AA size cylindrical nickel-hydrogen secondary battery which has the structure shown in FIG. 1 was assembled.

[Comparative Example 80]

27.5 g / m scale amount produced in the same manner as in Example 111 Two non-woven fabrics made of polytetrafluoroethylene fibers were laminated, and these were thermocompressed laminated to give a scale of 55 g / m. And a thickness of 0.20 mm was produced.

Next, the separator was sandwiched between the same negative electrode and the positive electrode of Example 110 and wound in a vortex to form an electrode group. The electrode group was housed together with the electrolyte solution having the same composition as in Example 110 in a bottomed cylindrical container to assemble an AA size cylindrical nickel-hydrogen secondary battery having the structure shown in FIG.

[Comparative Example 8l]

27.5 g / m scale amount produced in the same manner as in Example 111 Two polytetrafluoroethylene fiber nonwoven fabrics were subjected to plasma treatment under the same conditions as in Example 112. Thermo-compression lamination is integrated and the scale amount is 55g / m And a thickness of 0.20 mm was produced.

Next, the separator was sandwiched between the negative electrode and the positive electrode as in Example 110 and wound in a vortex to form an electrode group. This electrode group was housed together with the electrolyte solution of the same composition as Example 110 in a cylindrical container with a bottom, and the AA size cylindrical nickel-hydrogen secondary dust having the structure shown in FIG. 1 was assembled.

In the secondary batteries obtained in Examples 110 to 112 and Comparative Examples 80 to 81, the positive electrode terminal 10 and the rubber safety valve 11 were removed, and the inside of the container of the battery breakdown voltage measuring device shown in FIG. It was stored and the battery breakdown voltage was measured.

The maximum battery withstand voltage when 480% of the secondary batteries of Examples 110 to 112 and Comparative Examples 80 to 81 were charged at a current value of 0.5 CmA was measured, and the results are shown in Table 17 below.

As apparent from Table 17, it can be seen that the secondary batteries of Examples 110 to 112 of the present invention can reverse the withstand voltage increase during overcharging as compared with those of Comparative Examples 80 to 81. This is because the separator used in the secondary batteries of Examples 110 to 112 has a surface formed of a water-repellent synthetic resin fiber, which is disposed so as to face the negative electrode and absorbs the oxygen gas generated during overcharging to the negative electrode surface. This is because the artisan three-phase interface is widely distributed. This improvement in gas absorption characteristics was confirmed to achieve the same effect when hydrogen gas was generated from the positive electrode during reverse charging as well as during overcharging.

On the other hand, the secondary battery of the comparative example 80 provided with the separator which consists of a non-woven fabric made of polytetrafluoroethylene fiber has the negative problem shown below (1) as a problem before deteriorating electrolyte holding property of a separator and discussing gas absorptivity in the negative polar interface. The internal pressure rose because the electrochemical hydrogen absorption reaction of the pole was alienated.

In addition, the secondary battery of Comparative Example 81 equipped with a separator made of a polytetrafluoroethylene fiber nonwoven fabric subjected to plasma treatment had poor hydrophobic parts at the negative electrode interface, resulting in poor gas absorption performance and increased internal pressure.

The charge / discharge cycle of discharging the secondary dusts of the obtained Examples 11-112 and Comparative Examples 80-81 at 150% at 1CmA and discharging the battery voltage at 1.0C at 1.0C was set to 1 cycle. The cycle was repeated. At this time, the discharge capacity was calculated from the time until the battery voltage reached 1.0 V at 1 CmA for each cycle.

The results of the charge / discharge cycle characteristic test are shown in FIG. Discharge capacity ratio of the vertical axis | shaft of FIG. 20 shows the discharge capacity in the subsequent cycle of the secondary battery of Examples 110-112 and Comparative Examples 80-81, making the discharge capacity of the 1st cycle of Example 110 100. . The cycle number ratio along the horizontal axis in FIG. 20 is l00 as the number of cycles in which the discharge capacity of the secondary battery of Example 110 reached 80% of the discharge capacity of the first cycle, and was set to Examples 110 to 12 and Comparative Examples 80 to 81. The cycle number is shown.

As apparent from FIG. 20, it can be seen that the secondary batteries of Examples 110 to 112 of the present invention have a longer charge / discharge cycle life than the secondary batteries of Comparative Examples 80 to 81.

This is because the separators used in Examples 110 to 112 have a hydrophilic synthetic resin fiber nonwoven fabric, and have excellent electrolyte solution retention for a long time and can suppress an increase in internal resistance due to exhaustion of the electrolyte solution. In particular, it can be seen that the secondary batteries of Examples 110 to 111 have a longer charge / discharge cycle life than the secondary batteries of Example 112. This is because the separator used in the secondary battery examples of Examples 110 to 111 has a high hydrophilic monomer and has higher electrolytic solution holding performance than the separator of Example 112.

On the contrary, the cycle life of the secondary battery of Comparative Example 80 is short because the electrochemical hydrogen storage reaction of the negative electrode shown in (3) is eliminated and the discharge capacity is reduced. In addition, in the secondary battery of Comparative Example 81, the cycle pressure was shortened because the internal pressure increased with the progress of the charge / discharge cycle, and thus a gas leak occurred.

As described above, according to the present invention, it is possible to provide a method for manufacturing a nickel-hydrogen secondary battery and a nickel-hydrogen secondary battery that achieves a longer lifetime.

According to the present invention, it is possible to provide a nickel-hydrogen secondary battery having improved self-discharge characteristics at high temperature storage, excellent current discharging characteristics, and long life.

In addition, according to the present invention, it is possible to provide a nickel-hydrogen secondary battery that has achieved a long life by suppressing an increase in battery internal pressure during overcharging.

Claims (18)

A separator comprising a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a polyolefin-based synthetic resin fiber having an ion exchange group interposed between the positive electrode and the negative electrode, and having a concentration of about 5 The ion exchange amount (Y) when the above-mentioned alkali electrolyte solution is provided and the alkali electrolyte solution equivalent weight per battery capacity of 1Ah is X (meq / Ah), and the ion exchange amount per Y battery capacity of the separator is Y (meq / Ah). Is the following formula (1) {0.409- (X / 55)} ≤Y≤ {0.636+ (2X / 55)} ... (1) Ni-MH secondary battery, characterized in that to satisfy. The ion exchange amount (Y) (meq / Ah) of the separator according to claim 1, wherein {0.455- (X / 55)} ≤ Y ≤ {0.545 + (2X / 55)} ... (2) Ni-MH secondary battery, characterized in that to satisfy. A positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkali electrolyte solution, the separator is a polyolefin-based synthetic resin having an ion exchange group A nickel-hydrogen secondary battery characterized by forming the ion exchanger in the form of a salt by treating a sheet-like article containing fibers with an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte. 4. The nickel-hydrogen secondary battery according to claim 3, wherein an ion exchange amount of the separator is 0.2 to 2.0 meq / g. A method for producing a nickel-hydrogen secondary battery comprising a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, and an alkaline electrolyte solution. Graft-copolymerizing a vinyl monomer having ionic groups by irradiating ultraviolet rays to a sheet-like material containing polyolefin-based synthetic resin fibers not containing tablets, and treating the sheet-like material with an alkaline aqueous solution having the same type and concentration ratio as the alkaline electrolyte solution. The method for producing a nickel-hydrogen secondary battery, characterized in that the separator is produced by a method provided. 6. The method of claim 5, wherein the vinyl monomer is an acrylic acid monomer. 6. The method of claim 5, wherein the electrolyte solution contains at least one of lithium hydroxide or sodium hydroxide. The method of claim 5, wherein the hydrogen storage alloy is LmNi _X Mn _y A _Z (However, A is at least one metal selected from A1, Co, atomic ratio (x, y, z) is a total value of 4.8≤x + y + z ≤ 5,4). A method for producing a nickel-hydrogen secondary battery characterized by the above-mentioned. A positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, a separator interposed between the positive electrode and the negative electrode, an alkali electrolyte solution, and the separator is a polyolefin-based synthetic resin having an ion exchange group When the average diameter of all the fibers constituting the separator and the average diameter of all the fibers constituting the separator are X 占 퐉 and the ion exchange amount of the separator is Ymeq / g, they are represented by the following formulas (3) and (4) Satisfying, (0.05X + 0.05) Y 2.0 (3) One X 20 (4) The alkaline electrolyte is nickel-hydrogen secondary battery comprising at least one of lithium hydroxide or sodium hydroxide. 10. The separator according to claim 9, wherein the first surface of the separator exhibits hydrophilicity, and the second surface positioned opposite to the first surface has a hydrophilic portion and a hydrophobic portion, and the separator is disposed between the positive electrode and the negative electrode. Nigel hydrogen secondary battery, characterized in that the second surface is disposed so as to be located on the negative electrode side. The ion exchange amount (Y) (meq / g) of the separator according to claim 9, wherein (0.05X + 0.15)} ≤ Y≤ 1.2 (5) Ni-MH secondary battery, characterized in that to satisfy. The said average diameter X (micrometer) of the said separator is a following formula (6). 3 ≦ X ≦ 15... … … (6) Nickel-hydrogen secondary battery that satisfies the requirements. A positive electrode comprising nickel hydroxide, a negative electrode containing hydrogen absorbing alloy, a separator, and an alkali electrolyte solution, wherein the separator comprises a sheet comprising a water repellent synthetic resin fiber and a sheet containing synthetic resin fibers having hydrophilicity. And the separator is arranged such that the sheet containing the water-repellent synthetic resin fibers is positioned on the negative electrode side between the positive electrode and the negative electrode. 10. The nickel-hydrogen secondary battery according to any one of claims 1, 3, or 9, wherein the ion exchange group is at least one selected from carboxyl groups, sulfone groups, and hydroxyl groups. 10. The nickel-hydrogen secondary battery according to any one of claims 1, 3, or 9, wherein the ion exchange group of the polyolefin synthetic resin fiber is formed by graft copolymerization of a vinyl monomer having an ion exchange group. 16. The nickel hydrogen secondary battery of claim 15, wherein the vinyl monomer is an acrylic acid monomer. The nickel-hydrogen secondary battery according to any one of claims 1, 3 and 13, wherein the electrolyte solution includes at least one of lithium hydroxide and sodium hydroxide. The hydrogen storage alloy according to any one of claims 1, 3, 9 or 13, wherein the hydrogen storage alloy is formed of LmNi _X Mn _y A _Z (where A is at least one metal, atomic ratio ( x, y, z) is 4.8 x + y + z Nickel hydride secondary battery).