JPH06150971A - Cylindrical nonaqueous electrolyte secondary battery - Google Patents

Abstract

PURPOSE:To provide a cylindrical nonaqueous secondary battery excellent in the charge/discharge cycle characteristics. CONSTITUTION:A belt-like negative electrode and a belt-like positive electrode are wound into a spiral shape across a separator, a spiral electrode 15 fixed with the winding completion section by an adhesive tape 20 and a nonaqueous electrolyte are stored in a battery can to form a cylindrical nonaqueous electrolyte secondary battery, and (k) is set to k >=0.6, where L is the outer diameter of the spiral electrode 15 and kpiL is the length along the outer diameter of the adhesive tape 20 fixing the winding completion section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical non-aqueous electrolyte secondary battery in which an electrode and a strip separator are laminated and a spirally wound electrode is inserted into a battery can.

[0002]

2. Description of the Related Art Recent remarkable advances in electronic technology have made electronic devices smaller and lighter one after another. Along with this, there is an increasing demand for batteries as mobile power sources that are smaller, lighter, and have higher energy density.

Conventionally, an aqueous solution type battery such as a lead battery or a nickel-cadmium battery has been mainly used as a secondary battery for general use. Although these batteries have excellent cycle characteristics,
It cannot be said that the characteristics are sufficiently satisfactory in terms of battery weight and Lunergi density.

Recently, non-aqueous electrolyte secondary batteries using lithium or a lithium alloy as a negative electrode have been actively researched and developed. This battery has high energy density, low self-discharge, and excellent characteristics such as light weight, but as the charge / discharge cycle progresses, lithium grows into dendrite-like crystals during charging and reaches the positive electrode, causing an internal short circuit. There is a drawback that the possibility of reaching a high level is high, which is a major obstacle to practical use.

On the other hand, the non-aqueous electrolyte secondary battery using a carbon material for the negative electrode has lithium preliminarily supported on the carbon material by chemical and physical methods, lithium in the crystal structure of the positive electrode active material, Such as lithium dissolved in the electrolyte,
It utilizes doping / dedoping between carbon layers, and does not show dendrite-like precipitation during charging even if the charging / discharging cycle progresses, and exhibits excellent charging / discharging cycle characteristics exceeding 1000 times.

Non-aqueous electrolyte secondary batteries using these materials include video cameras, laptops, personal computers, etc., but most of these devices have relatively large current consumption. The spiral electrode structure is effective as the battery structure. This is a spirally wound band-shaped positive electrode and band-shaped negative electrode with a separator interposed therebetween, and since a large electrode area can be obtained, a heavy load can be endured.

On the other hand, the battery characteristics tend to be better when pressure is applied between the electrodes. However, when inserting such an electrode into a battery can in the process of assembling a battery, it is necessary to provide some clearance between the outer diameter of the electrode and the inner diameter of the battery can from the viewpoint of productivity. In general, a method of fixing the outermost peripheral end of the wound electrode with an adhesive tape so that it does not loosen is adopted. As disclosed in Japanese Patent Application No. 2-317428, the present inventor defines the occupancy ratio of the adhesive tape in the width direction with respect to the width direction of the electrode.
It has been found that the charge / discharge cycle characteristics of the non-aqueous electrolyte secondary battery are improved.

[0008]

However, even if this method is adopted, there is a problem that lots with insufficient cycle deterioration occur due to various fluctuation factors. Therefore, in order to produce a more reliable non-aqueous electrolyte secondary battery, development of a method for further improving cycle deterioration is desired.

The present invention has been made in view of the above problems, and an object thereof is to obtain a cylindrical non-aqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics.

[0010]

A cylindrical non-aqueous electrolyte secondary battery of the present invention is, for example, as shown in FIG. 1, spirally wound so that a strip negative electrode and a strip positive electrode are laminated with a separator interposed therebetween. In a cylindrical non-aqueous electrolyte secondary battery in which a spirally wound electrode 15 whose end of winding is fixed with an adhesive tape 20 is housed in a battery can together with a non-aqueous electrolyte, the spirally wound electrode 15 When the outer diameter is L and the length along the outer diameter of the adhesive tape 20 for fixing the winding end portion is kπL, k ≧ 0.6.

Further, the cylindrical non-aqueous electrolyte secondary battery of the present invention is, for example, as shown in FIG. 6, spirally wound so that a strip negative electrode and a strip positive electrode are laminated via a separator,
In a cylindrical non-aqueous electrolyte secondary battery in which a spirally wound electrode 15 whose end of winding is fixed using an adhesive tape 20 is housed in a battery can together with a non-aqueous electrolyte, the adhesive tape 20 is a support. The support has an adhesive layer on the top, and the support is made of a material that swells upon contact with the electrolytic solution and expands in volume.

Further, in the cylindrical non-aqueous electrolyte secondary battery of the present invention, the strip-shaped negative electrode and the strip-shaped positive electrode are spirally wound so as to be laminated with the separator interposed therebetween, and the winding end portion is coated with the adhesive tape 20. In a cylindrical non-aqueous electrolyte secondary battery in which a fixed spiral electrode 15 is housed in a battery can together with a non-aqueous electrolyte, the outer diameter of the spiral electrode 15 is set to L, and the end of winding is fixed. When the length of the pressure-sensitive adhesive tape 20 along this outer diameter is kπL, k ≧ 0.6, and the pressure-sensitive adhesive tape 20 has a pressure-sensitive adhesive layer on a support. It is made of a material that swells upon contact with a liquid and expands in volume.

[0013]

According to the cylindrical non-aqueous electrolyte secondary battery of the present invention,
The strip-shaped negative electrode and the strip-shaped positive electrode are spirally wound so as to be laminated via a separator, and the end of the winding is adhered to the adhesive tape 2
In a cylindrical non-aqueous electrolyte secondary battery in which a spirally wound electrode 15 fixed by using 0 is housed in a battery can together with a non-aqueous electrolyte, the outer diameter of the spirally wound electrode 15 is set to L, and winding ends. When the length of the pressure-sensitive adhesive tape 20 for fixing the parts along this outer diameter is kπL, the length of the pressure-sensitive adhesive tape is defined by setting k ≧ 0.6. Therefore, the cylindrical non-aqueous electrolyte solution is used. The charge / discharge cycle characteristics of the secondary battery can be improved.

Further, according to the cylindrical non-aqueous electrolyte secondary battery of the present invention, the strip negative electrode and the strip positive electrode are spirally wound so as to be laminated via the separator, and the end portion of the winding is covered with the adhesive tape 20. In a cylindrical non-aqueous electrolyte secondary battery in which the spiral electrode 15 fixed by using the non-aqueous electrolyte is housed in a battery can, the adhesive tape 20 has an adhesive layer on a support. Since the support is made of a material that swells upon contact with the electrolytic solution and expands in volume, the support of the adhesive tape swells upon contact with the electrolytic solution, so that the non-aqueous electrolyte secondary battery The charging / discharging cycle characteristic of can be improved.

Further, according to the cylindrical non-aqueous electrolyte secondary battery of the present invention, the strip negative electrode and the strip positive electrode are spirally wound so as to be laminated with the separator interposed therebetween, and the winding end portion is covered with the adhesive tape 20. In a cylindrical non-aqueous electrolyte secondary battery in which the spiral electrode 15 fixed by using the non-aqueous electrolyte is housed in a battery can, an outer diameter of the spiral electrode 15 is L and a winding end portion is When the length of the adhesive tape 20 to be fixed along this outer diameter is kπL, k ≧ 0.6, and the adhesive tape 20 has an adhesive layer on a support, and this support is By making it a material that swells and expands in volume upon contact with this electrolytic solution, the length of the adhesive tape to be attached to the outermost periphery is specified to prevent loosening of the spirally wound electrode. Contact of tape support with electrolyte Since more swellable, it is possible to improve the charge-discharge cycle characteristics of the nonaqueous electrolyte secondary battery.

[0016]

EXAMPLES An example of the cylindrical non-aqueous electrolyte secondary battery of the present invention will be described below with reference to FIGS.

FIG. 1 shows an example of a spiral electrode 15 of a cylindrical non-aqueous electrolyte secondary battery of the present example. The spiral electrode 15 has a strip-shaped positive electrode and a strip negative electrode between strip-shaped separators. It is sandwiched and wound in a spiral shape.

Reference numeral 11 denotes a negative electrode lead, and this negative electrode lead 11 makes an electrical connection between the above-mentioned negative electrode and a battery can to be the negative electrode of the battery.

Reference numeral 12 denotes a positive electrode lead, and this positive electrode lead 12 makes an electrical connection between the above-mentioned positive electrode and a battery lid to be the positive electrode of the battery.

Reference numeral 20 denotes an adhesive tape. The adhesive tape 20 is fixed so that the winding end portion of the spiral electrode 15 does not come off, and the adhesive tape 20 is attached so as to generate tension so that the spiral electrode 15 is attached to the spiral electrode. It also has the function of generating compressive force.

Next, a specific method for manufacturing the spiral electrode used in this example will be described. In this example, the first to fourth example batteries and the first comparative example battery were produced.

First Example Battery Negative electrode 1 was prepared as follows. Petroleum pitch is used as a starting material, and 10 to 20% by weight of a functional group containing oxygen is introduced into this (so-called oxygen cross-linking), followed by firing at 1000 ° C. in an inert gas stream to have properties similar to glassy carbon. A carbonaceous material was obtained. As a result of X-ray analysis measurement of this material, the spacing between (002) planes was 3.8A. The true specific gravity was measured by a pycnometer method and found to be 1.54 g / cm ³ . This carbon material was crushed to obtain a carbon material powder having an average particle size of 20 μm.

The carbon material powder thus obtained was used as a negative electrode active material carrier, and 90 parts by weight of this material and 10 parts by weight of vinylidene fluoride resin (PVDF) as a binder were mixed to prepare a negative electrode mixture. . This negative electrode mixture was dispersed in N-methylpyrrolidone as a solvent to form a slurry (paste).

A strip-shaped copper foil having a thickness of 10 μm was used as the negative electrode current collector, and the negative electrode mixture slurry was applied to both surfaces of this current collector, dried and then compression-molded to prepare a strip-shaped negative electrode 1.
The thickness of the mixture after molding was 80 μm on both sides, and the width of the electrode was 41.5 mm and the length was 720 mm.

The positive electrode 2 was manufactured as follows. 90 mol of lithium carbon and 1 mol of cobalt carbonate are mixed,
LiCoO ₂ was obtained by firing in air at 0 ° C. for 5 hours. X-ray diffraction measurement was performed on the obtained material, and JCP
It was in good agreement with the peak of LiCoO ₂ registered in the DS film. This material is crushed to give a 50% cumulative particle size of 15μ.
m LiCoO ₂ powder was obtained. A mixture of 95 parts by weight of LiCoO ₂ powder and 5 parts by weight of lithium carbonate powder was added to the mixture.
By weight, 6 parts by weight of graphite as a conductive agent and 3 parts by weight of vinylidene fluoride resin as a binder were mixed to prepare a positive electrode mixture, which was dispersed in N-methylpyrrolidone to form a slurry (paste form).

A strip-shaped aluminum foil having a thickness of 20 μm is used as a positive electrode current collector, and the positive electrode mixture slurry is uniformly applied to both surfaces of the current collector, dried and then compression molded to produce a strip positive electrode 2. did. The thickness of the mixture after molding is 70μ on both sides.
The width of the electrode is 40.5 mm and the length is 660.
mm.

Strip negative electrode 1, strip positive electrode 2 and thickness 25 μ
A separator 3 made of a microporous polypropylene film having a width of m and a width of 44 mm was laminated in this order on the negative electrode, the separator, the positive electrode, and the separator, and then this laminated body was wound in a spiral shape many times. An adhesive tape 20 having a width of 40 mm and a length of 41 mm, which has a 25 μm-thick polyester film as a support at the outermost circumference and is coated with a silicon-based adhesive.
Then, an electrode having an outer diameter of 19.6 mm was prepared. Also,
Adhere the tape leaving 2 mm each on both ends in the width direction.
A spiral electrode as shown in 1 was produced.

As shown in FIG. 2, the spiral electrode thus prepared is plated with nickel to make an iron battery can 5.
Stored in. Insulating plates 4 are provided on both upper and lower surfaces of the spirally wound electrode, an aluminum positive electrode lead 12 is led out from the positive electrode current collector, and a nickel negative electrode lead 11 is led out from the negative electrode current collector to a battery can. Welded to 5. Into this battery can 5, an electrolyte solution in which LiPF ₆ was dissolved at a ratio of 1 mol / 1 in a mixed solvent of equal volume of propylene carbonate and diethyl carbonate was injected.

By caulking the battery can 5 through the insulating sealing gasket 6 whose surface is coated with asphalt, the safety valve device 8 having a current cutoff mechanism and the battery lid 7 are fixed to keep the airtightness inside the battery. .

A cylindrical non-aqueous electrolyte battery having a diameter of 20 mm and a height of 50 mm was manufactured as a prototype with the above structure.

Second Example Battery A polyester-based tape 20 having a width of 40 mm and a length of 56 mm was applied to the outermost end of the spirally wound electrode at the end of winding, leaving 2 mm at each end in the width direction (see FIG. 3). Except for the above, a cylindrical nonaqueous electrolyte battery having a diameter of 20 mm and a height of 50 mm as shown in FIG. 2 was manufactured in the same manner as the first example battery.

Third Example Battery A polyester tape 20 having a width of 40 mm and a length of 66 mm is used at the outermost end of the spirally wound electrode to leave a width of 2 mm each at both ends in the width direction so that the two parts overlap each other. 20 mm in diameter and 50 mm in height as shown in FIG. 2 by the same method as the battery of the first example except that it was attached to the battery (see FIG. 4).
A cylindrical non-aqueous electrolyte battery was manufactured as a prototype.

First Comparative Example Battery The outermost winding end of the spirally wound electrode was attached using a polyester tape 20 having a width of 40 mm and a length of 20 mm, leaving 2 mm at each end in the width direction (see FIG. 5). Except for the above, a cylindrical nonaqueous electrolyte battery having a diameter of 20 mm and a height of 50 mm as shown in FIG. 2 was manufactured in the same manner as the first example battery.

The spiral electrode of this example can be manufactured not only by the method according to the above-mentioned embodiment but also by another method.

That is, as the negative electrode, it is possible to use a carbon material capable of being doped / dedoped with an alkali metal such as lithium in association with a charge / discharge reaction. For example, graphite, pyrolytic carbons, cokes (petroleum coke, pitch coke,
Coal coke, etc.), carbon black (acetylene black, etc.), glassy carbon, fired organic polymer material (organic polymer material in an inert gas stream or in a vacuum 5
Carbon fiber or the like, which is fired at a suitable temperature of 00 ° C. or higher) is used. In addition, these materials are used alone,
Used as a complex or mixture.

It is preferable that the (002) plane has an interplanar spacing of 3.70 Å or more and a true density of less than 1.70 g / cm ³ and a differential thermal analysis in an air stream of 700 ° C.
As described above, a carbonaceous material having no exothermic peak is used.

Examples of the material having such a property include a carbonaceous material obtained by carbonizing an organic material by a technique such as firing, and furfuryl alcohol or furfural homopolymer or copolymer is used as a starting material for carbonization. Furan resin consisting of is preferred. In particular,
Furafural + phenol, furfuryl alcohol + dimethylol urea, furfuryl alcohol, furfuryl alcohol + formaldehyde, furfuryl alcohol +
A polymer composed of furfural, furfural, and ketones shows very good characteristics as a negative electrode agent for a non-aqueous electrolyte secondary battery.

Alternatively, a petroleum pitch having a hydrogen / carbon atom ratio of 0.6 to 0.8 is used as a raw material, a functional group containing oxygen is introduced into the petroleum pitch, and so-called oxygen cross-linking is performed to obtain an oxygen content of 10 to 20% by weight. A carbonaceous material obtained by firing after the precursor of is also suitable.

Further, it is also possible to use a carbon material having a large doping amount with respect to lithium by adding a phosphorus compound or a boron compound when carbonizing the furan resin or petroleum pitch.

On the other hand, Li _X MO ₂ (where M represents at least one transition metal, preferably at least one of Co and Ni, and 0.05 ≦ X ≦ 1.10) is used for the positive electrode. An active material containing is used. Examples of the active material include LiCoO ₂ , LiNiO ₂ , and LiNi _y Co.
_(1-y) O ₂ (however, 0.05 ≦ X ≦ 1.10, 0 <y <
The complex oxide represented by 1) is mentioned.

The above-mentioned composite oxide is obtained, for example, by mixing carbonates such as lithium, cobalt, and nickel according to the composition and firing in a temperature range of 600 ° C. to 1000 ° C. in an atmosphere containing oxygen. The starting material is not limited to carbonate, and it can be similarly synthesized from hydroxide or oxide.

As the electrolytic solution, for example, an electrolytic solution in which a lithium salt is used as an electrolyte and this is dissolved in an organic solvent is used. Here, the organic solvent is not particularly limited, but for example, propylene carbonate, ethylene carbonate, diethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1,3 -Dioxolane,
4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile,
A single solvent or a mixed solvent of two or more kinds such as propiotrilyl can be used. Any known electrolyte can be used as the electrolyte, such as LiClO ₄ , LiAsF ₆ , and LiP.
F ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiCl, L
There are iBr, CH ₃ SO ₃ Li, CF ₃ SO ₃ Li and the like.

Various tapes can be used for the outermost periphery of the spiral electrode, but the materials of the tape and the adhesive are stable to the organic solvent of the electrolytic solution, and the adhesive of the tape It can be selected in consideration of the adhesive strength to the separator wound around the outer periphery and the like. In particular, it is desirable to use polyethylene, polypropylene, polyvinyl chloride, polyester, polyimide, and fluororesin tapes for the electrolytic solution generally used in this type of battery.

Next, 20 batteries each prepared in the above-mentioned embodiment are prepared, the upper limit voltage is set to 4.2 V, and 1 A is set.
After charging for 2.5 hours at a constant current of 1., the charging / discharging cycle of discharging to 2.75 V at a constant current of 400 mA was repeated.

The capacity at the 10th cycle of these batteries (hereinafter referred to as the initial capacity) and the average value of the capacity at the 100th cycle (each n = 20) were used to fix the winding end portion of each electrode. It is shown in Table 1 together with the tape length.

[0046]

[Table 1]

As shown in Table 1, the first to third batteries of the present example have larger capacities after the passage of the cycle and the deterioration rate with the progress of the charge / discharge cycle as compared with the first comparative battery of the conventional method. small.

As shown above, the battery of this example has a high capacity and an excellent cycle life. In the description of the examples, the case of fixing with one piece of adhesive tape was shown, but it is also possible to divide it into a plurality of pieces and attach them intermittently so that the total length falls within the scope of the present invention. Is. In this case, one of the plurality of sheets is used to fix the winding end portion.

In the description, the width of the adhesive tape covers almost the entire area of the electrode (separator), but it is not always necessary to secure this width. However, it is desirable to cover a portion of 40% or more of the electrode width. In this case, as a method of attaching the tapes, one tape or a plurality of tapes may be used. When the tapes are fixed by a plurality of tapes, the total width of each tape is 4 with respect to the electrode width.
It should be 0% or more.

From the above, according to this example, the length of the adhesive tape attached to the outermost periphery in order to prevent the loosening of the spirally wound electrode is regulated, whereby the cylindrical non-aqueous electrolyte secondary battery is provided. The charging / discharging cycle characteristic of can be improved.

In the above embodiment, when the outer diameter of the spiral electrode is L and the length along the outer diameter of the adhesive tape for fixing the winding end portion is kπL, k ≧ 0.6. Study was carried out.

When the support having a thickness of 25 μm of the embodiment is used, the effect does not change even if k ≧ 2, and if k is made too large, the volume of the electrode is reduced by the volume. However, if you use a thinner adhesive tape,
It is also possible that k is 2 or more.

Next, another embodiment of the cylindrical non-aqueous electrolyte secondary battery of this embodiment will be described with reference to FIGS. 6 to 10.

FIG. 6 shows a spiral electrode used in another example of the cylindrical nonaqueous electrolyte secondary battery of this example. Although the structure of this spiral electrode is almost the same as that of the above-mentioned embodiment, in the above-mentioned embodiment, the adhesive tape which does not swell by the electrolytic solution was used, but in this embodiment, the adhesive tape having swelling property. Is used.

Next, a specific method for manufacturing the spiral electrode used in this example will be described. In this example, the fourth to sixth example batteries and the second comparative example battery were produced.

Here, the negative electrode 1, the negative electrode current collector 9, the positive electrode 2,
The positive electrode current collector 10 and the positive electrode current collector 10 were manufactured by the same method as that of the above-described example.

Fourth Example Battery Band-shaped negative electrode 1, band-shaped positive electrode 2 and thickness 25 μm, width 44 mm
The negative electrode, the separator, the positive electrode, and the separator were laminated in this order on the separator 3 made of the microporous polypropylene film, and then the laminated body was wound in a spiral shape many times. The end of the outermost winding is fixed with an adhesive tape 20 having a width of 40 mm and a length of 56 mm, which is coated with an acrylic resin-based pressure sensitive adhesive, using a vinylidene fluoride resin film having a thickness of 30 μm as a support, and has an outer diameter of 19. A 6 mm electrode was prepared. Further, the tape was attached while leaving both widthwise end portions of 2 mm each, to produce a spiral electrode as shown in FIG.

In order to check the swelling property of this base film, a test piece of 50 mm × 60 mm was used, which was dipped in the electrolyte used for 6 hours and the volume expansion coefficient of this base film was measured. It was about 40%.

As shown in FIG. 7, the spiral electrode thus produced was plated with nickel to make an iron battery can 5.
Stored in. Insulating plates 4 are provided on both upper and lower surfaces of the spirally wound electrode, an aluminum positive electrode lead 12 is led out from the positive electrode current collector, and a nickel negative electrode lead 11 is led out from the negative electrode current collector to a battery can. Welded to 5. Into this battery can 5, an electrolyte solution in which LiPF ₆ was dissolved at a ratio of 1 mol / 1 in a mixed solvent of equal volume of propylene carbonate and diethyl carbonate was injected.

By caulking the battery can 5 through the insulating sealing gasket 6 whose surface was coated with asphalt, the safety valve device 8 having the current cutoff mechanism and the battery lid 7 were fixed to maintain the airtightness inside the battery. .

A cylindrical non-aqueous electrolyte battery having a diameter of 20 mm and a height of 50 mm was manufactured as a prototype with the above-mentioned structure.

Fifth Present Example Battery The same method as in the fourth present example battery except that the material of the base film in the adhesive tape for fixing the winding end portion of the outermost periphery of the electrode is a crosslinked polyethylene oxide resin. A spiral electrode as shown in FIG. 6 was produced, and a cylindrical nonaqueous electrolyte battery having a diameter of 20 mm and a height of 50 mm as shown in FIG. The volume expansion coefficient due to the swelling of the base film was about 820%.

Sixth Example Battery The same method as in the fourth example battery except that the material of the base film of the adhesive tape for fixing the winding end portion of the outermost periphery of the electrode is uniaxially stretched vinyl chloride resin. A spiral type electrode as shown in FIG. 6 was produced, and a cylindrical non-aqueous electrolyte battery having a diameter of 20 mm and a height of 50 mm as shown in FIG. The volume expansion coefficient due to the swelling of the base film was about 20%.

Second Comparative Example Battery The same method as in the fourth example battery except that the material of the base film in the adhesive tape for fixing the winding end portion of the outermost periphery of the electrode was polyester resin was used. A spiral type electrode as shown in FIG.
A cylindrical non-aqueous electrolyte battery having a height of 0 mm and a height of 50 mm was manufactured as a prototype.

The adhesive tape used for the spiral electrode of this example is
It can be manufactured not only by the method according to the above-described embodiment but also by other methods.

That is, as the adhesive tape for fixing the outermost winding end portion of the spirally wound electrode, various materials can be used in which the base film swells and expands in volume upon contact with the electrolytic solution.

The swelling of the base film appears as a result of a change caused by dissolution of the material, a change caused by a chemical reaction of the material, a change caused by the restoring force of the material subjected to mechanical pretreatment such as stretching, and the like. It is a phenomenon.

Of the high molecular compound to be the base film,
Factors that control the ease of swelling due to dissolution include the dielectric constant and polarity of the electrolytic solution with respect to the organic solvent. In addition, swelling due to chemical changes means that the solvent and solute in the electrolytic solution chemically react with the polymer compound that becomes the base film,
It refers to a material whose volume expands due to the production of a new material. Further, the swelling due to mechanical properties means that the base film that has been subjected to mechanical pretreatment such as stretching contracts in the lengthwise direction to restore the thickness before the treatment. The best base for either case
The material of the film is determined by the type of electrolyte used.

Here, the swelling means not only the increase in the thickness of the film directly, but almost no change in the original thickness of the film is observed, but the increase in the length direction causes wrinkles. Those that appear and have the same effect as when the thickness is increased are also included.

The pressure-sensitive adhesive applied to the tape can be variously selected in consideration of the pressure-sensitive adhesive strength to the separator wound on the outermost periphery, but is stable to the organic solvent of the electrolytic solution used. Is desirable.

Next, 20 batteries each prepared in the above-mentioned embodiment and 20 batteries were prepared, the upper limit voltage was set to 4.2 V, and 1 A was set.
After charging for 2.5 hours at a constant current of 1., the charging / discharging cycle of discharging up to 2.75 V at a constant current of 400 mA was repeated.
In addition, at the time of inserting the electrode between the electrode outer diameter ~
Since a sufficient clearance was secured between the inner diameters of the cans for production, no defective insertion occurred in both the fourth to sixth batteries of this example and the second comparative battery.

The capacity of the 10th cycle (initial capacity) of these batteries and the average value of the capacity of the 100th cycle (n
= 20) is shown in Table 2. Also, after 100 cycles, the battery was disassembled, and the presence or absence of swelling of the base film of the adhesive tape used for fixing the winding end portion of each electrode was examined.
It is also shown in Table 2.

[0073]

[Table 2]

As shown in Table 2, the battery of the present invention has a large capacity after a lapse of cycles and a small deterioration rate due to the progress of charge / discharge cycles, as compared with the battery of the comparative example by the conventional method. This is the appearance of the base film of the adhesive tape taken out from the battery of Example 4 after 100 cycles (see FIG. 9).
As can be seen from the figure, the film swollen by the contact with the electrolyte fills the clearance between the outer diameter of the electrode and the inner diameter of the battery can, and the force that presses the electrode from the outer peripheral direction toward the center works smoothly, and the electrode reaction smoothly. It is thought that this was done. The appearance of the base film taken out from the second comparative battery is shown in FIG.

According to this example, a battery having a high capacity and excellent cycle characteristics can be mass-produced with high productivity. In the description of the examples, the case of fixing with one piece of adhesive tape made of a base film made of a material that swells in an electrolytic solution is shown. After fixing with a tape, a swelling tape may be further attached to the outer periphery thereof, or a swelling film may be inserted between the electrode and the can to expect the same effect.

Regarding the swelling property of the base film used in the above-mentioned examples, the volume expansion coefficient was 5 as a result of immersing the base film in an electrolyte solution at room temperature for one day.
% Or more, and if 10% or more, further preferable effects can be obtained.

From the above, according to this example, the material of the base film of the adhesive tape attached to the outermost periphery in order to prevent the spirally wound electrode from being loosened is changed to the material which swells by contact with the electrolytic solution. By doing so, the charge / discharge cycle characteristics of the non-aqueous electrolyte secondary battery can be improved. Further, it is of course possible to use the adhesive tape with various lengths.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0079]

As described above, according to the present invention,
By defining the length of the adhesive tape that is attached to the outermost circumference of the spiral electrode and by making the material of the base film of the adhesive tape a material that swells when contacted with the electrolytic solution, The charge / discharge cycle characteristics of the liquid secondary battery can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a spiral electrode of an example of a cylindrical non-aqueous electrolyte secondary battery of the present invention.

FIG. 2 is a cross-sectional view showing an example of the cylindrical non-aqueous electrolyte secondary battery of the present invention.

FIG. 3 is a perspective view showing a spiral electrode of an example of the cylindrical non-aqueous electrolyte secondary battery of the present invention.

FIG. 4 is a configuration diagram showing a spiral electrode of an example of the cylindrical non-aqueous electrolyte secondary battery of the present invention.

FIG. 5 is a perspective view showing a spiral electrode of a comparative example of a cylindrical non-aqueous electrolyte secondary battery.

FIG. 6 is a configuration diagram showing a spiral electrode of another embodiment of the cylindrical non-aqueous electrolyte secondary battery of the present invention.

FIG. 7 is a sectional view showing another embodiment of the cylindrical non-aqueous electrolyte secondary battery of the present invention.

FIG. 8 is a perspective view showing a spiral electrode of a comparative example of a cylindrical non-aqueous electrolyte secondary battery.

FIG. 9 is an explanatory diagram showing a base film of an adhesive tape taken out from the spiral electrode of this example.

FIG. 10 is an explanatory diagram showing a base film of an adhesive tape taken out from a spiral electrode of a comparative example.

[Explanation of symbols]

 11 Negative electrode lead 12 Positive electrode lead 15 Swirl type electrode 20 Adhesive tape

Continued Front Page (72) Inventor Atsushi Komaru 1-1 Takashimo Shimosugishita, Takakura, Hiwada-cho, Koriyama-shi, Fukushima Prefecture Sony Energy Tech Co., Ltd. Koriyama Plant (72) Naoyuki Date Date Takakura, Hiwada-cho, Koriyama-shi, Fukushima Prefecture 1-1 Shimoshita Sugishita Sony Energy Tech Koriyama Factory

Claims (3)

[Claims] 1. A spirally wound electrode in which a strip negative electrode and a strip positive electrode are spirally wound so as to be laminated with a separator interposed therebetween, and a winding end portion is fixed with an adhesive tape in a battery can together with a non-aqueous electrolyte. In the cylindrical non-aqueous electrolyte secondary battery housed in, when the outer diameter of the spiral electrode is L and the length along the outer diameter of the adhesive tape for fixing the winding end portion is kπL,
A cylindrical non-aqueous electrolyte secondary battery, wherein k ≧ 0.6. 2. A spirally wound electrode in which a strip negative electrode and a strip positive electrode are spirally wound so as to be laminated with a separator interposed therebetween, and a winding end portion is fixed with an adhesive tape in a battery can together with a non-aqueous electrolyte. In the cylindrical non-aqueous electrolyte secondary battery housed in, the pressure-sensitive adhesive tape has a pressure-sensitive adhesive layer on a support, and the support swells by contact with the electrolyte and expands in volume. A cylindrical non-aqueous electrolyte secondary battery comprising: 3. A spiral wound electrode in which a strip negative electrode and a strip positive electrode are spirally wound so as to be laminated via a separator, and the end of the winding is fixed with an adhesive tape in a battery can together with a non-aqueous electrolyte. In the cylindrical non-aqueous electrolyte secondary battery housed in, when the outer diameter of the spiral electrode is L and the length along the outer diameter of the adhesive tape for fixing the winding end portion is kπL,
k ≧ 0.6, and the pressure-sensitive adhesive tape has a pressure-sensitive adhesive layer on a support, and the support is made of a material that swells upon contact with the electrolyte and expands in volume. Cylindrical non-aqueous electrolyte secondary battery.