JP2009259536A - Planiform alkaline primary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planiform alkaline primary battery of low cost, high battery voltage, standing long-time use, and with high reliability. <P>SOLUTION: In the planiform alkaline primary battery 1, an anode can 3 is insertion-coupled to a circular opening of a cathode can 2 from an opening side where a gasket 4 is mounted, and, by caulking and sealing the opening of the cathode can 2 toward the gasket 4, an airtight space is formed between the cathode can 2 and the anode can 3 through the gasket 4. A cathode mixture 5, a separator 6 and an anode mixture 7 are housed in the airtight space, the cathode mixture 5 arranged at a cathode can 2 side and the anode mixture 7 at an anode can 3 side, with the separator 6 in between. Alkali electrolyte solution is filled in the airtight space. Zinc or zinc alloy powder is to be an anode active material, and nickel oxyhydroxide is to be a cathode active material, and silver-nickel complex oxide is contained as a conductive agent of the cathode mixture, fluorine resin powder as a dry lubricant. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flat alkaline primary battery.

  A flat alkaline primary battery such as a coin type or a button type used in a small electronic device such as an electronic wristwatch or a portable electronic computer has a positive electrode mixture containing manganese dioxide as a positive electrode active material contained in a positive electrode can. A negative electrode mixture containing zinc or zinc alloy powder as a negative electrode active material is disposed in the negative electrode can.

  The positive electrode mixture and the negative electrode mixture face each other via a separator, and an alkaline electrolyte is injected into the battery. The positive electrode mixture is mixed with manganese dioxide, graphite powder as a conductive agent, and, if the binding property of the positive electrode mixture is low, resin powder or emulsion such as polytetrafluoroethylene (PTFE) as a binder, and then pelletized To make a positive electrode.

  In addition, so-called silver oxide batteries using silver oxide as a positive electrode active material for flat alkaline primary batteries are also widely available in the general market. Silver oxide has a higher volumetric energy density than manganese dioxide, and the battery voltage with zinc as the negative electrode active material is flat in the vicinity of 1.56 volts. Therefore, the final voltage is mainly 1.2 volts or more. It is used as a power source for small electronic devices such as electronic wristwatches and portable electronic computers.

  However, silver oxide is expensive because its main component is silver, which is a precious metal with good performance, and the price fluctuates depending on the silver market price, and it is difficult to use for reducing production cost and stability. there were. Therefore, a so-called alkaline manganese battery using manganese dioxide as a positive electrode active material, which has a volume energy density lower than that of silver oxide and a large voltage drop due to discharge, but is overwhelmingly low at a price per mass of about 1/200. Like silver oxide batteries, it is on the general market.

For this reason, adding various additives to cheap active materials, such as manganese dioxide, is examined (for example, refer patent documents 1, 2, and 3).
JP 2003-234107 A (2nd to 3rd pages, FIG. 1) JP 2004-6092 A (2nd to 3rd pages, Fig. 1) JP 2005-19349 A (2nd page to 4th page, FIG. 1)

  By the way, a flat alkaline primary battery using a material such as manganese dioxide as a positive electrode active material has a problem in that the voltage drops significantly with discharge. In devices such as electronic wristwatches where the end voltage is set higher than the battery voltage of silver oxide batteries, there is a problem that the usage time of the device becomes extremely short due to the voltage drop caused by the discharge of manganese dioxide. It was. Various studies have been made on the prevention of voltage drop, but it has not been sufficient.

  As a solution, a battery using nickel oxyhydroxide as a positive electrode active material has been proposed. However, in the case of a battery using nickel oxyhydroxide as the positive electrode active material, although the battery voltage is higher than that of the silver oxide battery, the theoretical electric capacity per unit mass of nickel oxyhydroxide is 292 mAh / g and manganese dioxide 308 mAh / g. Less than (per manganese value). Therefore, it has been difficult to improve the capacity of a positive electrode battery using nickel oxyhydroxide as a positive electrode active material than a positive electrode battery using manganese dioxide as a positive electrode active material.

  In addition, nickel oxyhydroxide has no electrical conductivity and has a large volume swelling associated with electrolyte absorption and discharge. Therefore, it has been found that when the ratio of the conductive agent in the positive electrode mixture is low, there is a problem that the electronic conductivity is lowered due to the volume expansion associated with the electrolyte absorption and discharge, and the capacity and capacity preservation are markedly lowered.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a flat alkaline primary battery that is inexpensive and excellent in battery capacity and capacity storage.

  In the flat alkaline primary battery of the present invention, the opening of the negative electrode can is fitted into the opening of the positive electrode can, and the separator is disposed in a sealed space in which the positive electrode can and the negative electrode can are sealed with a gasket. A positive electrode mixture mainly composed of a positive electrode active material is arranged on the positive electrode side with a separator interposed therebetween, and a negative electrode mixture mainly composed of a negative electrode active material is arranged on the negative electrode side. A flat alkaline primary battery in which an alkaline electrolyte is filled in a sealed space in which a separator and a negative electrode mixture are disposed, wherein zinc or a zinc alloy powder is used as the negative electrode active material, nickel oxyhydroxide is used as the positive electrode active material, A silver / nickel composite oxide is included as a conductive agent of the positive electrode mixture, and a fluororesin powder is included as a dry lubricant of the positive electrode mixture.

  According to the flat alkaline primary battery of the present invention, the silver / nickel composite oxide is used as the conductive agent of the positive electrode mixture and the fluororesin powder is used as the dry lubricant. The binding force suppresses volume expansion associated with electrolyte absorption and discharge, prevents a decrease in electronic conduction due to volume expansion of the positive electrode, and provides a battery with excellent capacity and capacity storage.

In addition, since the fluororesin powder is used as the dry lubricant, the positive electrode mixture excellent in handling property can be obtained by improving the weighing property of the positive electrode mixture by the lubricity of the fluororesin powder.
In this flat alkaline primary battery, the silver / nickel composite oxide may have an average particle size of 1 to 20 μm.

  According to this, since the high conductivity and binding force of the silver / nickel composite oxide can be efficiently utilized, the handling ability of the positive electrode mixture is excellent without increasing the ratio to be mixed with the positive electrode mixture, and the capacity and A battery having excellent capacity storage can be obtained.

In this flat alkaline primary battery, the blending ratio of the silver / nickel composite oxide in the positive electrode mixture may be 5 mass% or more and 30 mass% or less.
According to this, since this silver / nickel composite oxide is not only high conductivity and binding power but also an active material having high electric capacity by itself, by adding an appropriate amount to the positive electrode mixture, There is no need to add graphite or the like having a low bulk density at a high ratio, and accordingly, the active material filling amount is ensured and a battery having an excellent capacity can be obtained.

In this flat alkaline primary battery, the fluororesin powder may have an average particle size of 0.1 to 10 μm.
According to this, since the excellent lubricity of the fluororesin powder can be utilized efficiently, the positive electrode mixture with excellent handling properties can be obtained by improving the weighability of the positive electrode mixture even in a low blending with the positive electrode mixture. it can.

In this flat alkaline primary battery, the blending ratio of the fluororesin powder in the positive electrode mixture may be 0.05 mass% or more and 5 mass% or less.
According to this, since the fluororesin powder has high lubricity even in a small amount, it is possible to improve the weighability of the positive electrode mixture and obtain a positive electrode mixture excellent in handling property even if it is blended in a low amount in the positive electrode mixture. In addition, since the fluororesin powder has water repellency, the fluororesin powder does not swell due to absorption of the electrolyte, and has an effect of reducing the blending ratio of the conductive agent in the positive electrode mixture. As a result, a battery having an excellent capacity can be obtained.

Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a button-shaped (flat) alkaline primary battery. In FIG. 1, an alkaline primary battery 1 is a button-type primary battery, and includes a bottomed cylindrical positive electrode can 2 and a covered cylindrical negative electrode can 3. The positive electrode can 2 has a structure in which nickel plating is applied to stainless steel (SUS), and also serves as a positive electrode terminal. On the other hand, the negative electrode can 3 is formed by pressing a three-layer clad material of an outer surface layer S1 made of nickel, a metal layer S2 made of stainless steel (SUS), and a current collector layer S3 made of copper into a cup shape. It is configured. Further, the negative electrode can 3 has a circular opening formed in a folded shape, and a ring-shaped gasket 4 made of, for example, nylon is attached to the folded-opened opening.

  Then, the negative electrode can 3 is fitted into the circular opening of the positive electrode can 2 from the opening side where the gasket 4 is mounted, and the opening of the positive electrode can 2 is crimped toward the gasket 4 and sealed. The positive electrode can 2 and the negative electrode can 3 are connected and fixed to each other. By connecting and fixing the positive electrode can 2 and the negative electrode can 3, a sealed space is formed between the positive electrode can 2 and the negative electrode can 3 via the gasket 4.

In this sealed space, the positive electrode mixture 5, the separator 6, and the negative electrode mixture 7 are accommodated, and the positive electrode mixture 5 is accommodated and disposed on the negative electrode can 3 side, and the negative electrode mixture 7 is accommodated on the negative electrode can 3 side with the separator 6 interposed therebetween. ing.
More specifically, the positive electrode mixture 5 is disposed on the bottom surface 2 b of the positive electrode can 2. The positive electrode mixture 5 is a cylindrical pellet structure in which nickel oxyhydroxide powder, a conductive agent, a dry lubricant, a binder, and an alkaline electrolyte as an electrolytic solution are mixed as a positive electrode active material and then press-molded with a tableting machine or the like. It is.

  The sealed space is preferably filled with an alkaline electrolyte, and at least the conductive material of the positive electrode mixture 5 contains silver / nickel composite oxide, and the dry lubricant preferably contains fluororesin powder.

  This is because, by using at least silver / nickel composite oxide as the conductive agent of the positive electrode mixture 5, even when the battery is stored at a high temperature, the silver / nickel composite oxide absorbs and discharges with high conductivity and binding power. This is because it is possible to suppress the volume expansion accompanying the above and prevent a decrease in electron conduction due to the volume expansion of the positive electrode, and thus it is possible to obtain a battery with excellent capacity storage stability.

  In addition, by using at least the fluororesin powder as the dry lubricant, it is possible to improve the weighability of the positive electrode mixture with the high lubricity of the fluororesin powder and to obtain a positive electrode mixture with excellent handling properties. . In addition, since the fluororesin powder has water repellency, it does not swell due to absorption of the electrolyte solution, and the blending ratio of the conductive agent in the positive electrode mixture can be reduced, so that a battery with excellent capacity can be obtained.

Further, the average particle diameter of the silver / nickel composite oxide as the conductive agent of the positive electrode mixture 5 is preferably 1 μm or more and 20 μm or less.
This is because when the average particle diameter of the silver / nickel composite oxide is less than 1 μm, the compressibility of the silver / nickel composite oxide is reduced, and the pressure when the positive electrode mixture 5 is processed into a pellet shape must be increased. This is because the molding jig may be deformed. In addition, when the average particle size exceeds 20 μm, the specific surface area of the silver / nickel composite oxide is reduced, so that the conductivity per unit mass is reduced, and the compounding ratio to the positive electrode mixture must be increased. This is because the cost is increased.

Moreover, it is preferable that the compounding ratio of the silver / nickel composite oxide as the conductive agent of the positive electrode mixture 5 is 5% or more and 30% or less.
This is because when the compounding ratio of the silver / nickel composite oxide is less than 5%, the binding force of the positive electrode mixture is low, the volume expansion associated with the absorption and discharge of the electrolyte is increased, the electron conduction is lowered, and the capacity and capacity are significantly preserved. This is because a problem that the performance is lowered occurs. On the other hand, if the blending ratio exceeds 30%, it is not preferable since the cost increases despite the fact that there is almost no merit in battery characteristics due to the improvement in conductivity of the positive electrode mixture and the suppression of volume expansion associated with the absorption and discharge of the electrolyte.

Moreover, it is preferable that the average particle diameter of a fluororesin powder is 0.1 micrometer or more and 10 micrometers or less as a dry lubricant of the positive mix 5.
This is because it is difficult to manufacture industrially such that the average particle size of the fluororesin powder is less than 0.1 μm with the current technology. Further, if the average particle diameter exceeds 10 μm, the lubricity per unit mass of the fluororesin powder is lowered, and the blending ratio to the positive electrode mixture 5 has to be increased. It must be reduced, which is not preferable.

  Further, the blending ratio of the fluororesin powder as the dry lubricant of the positive electrode mixture 5 is preferably 0.05% or more and 5% or less. This is because when the blending ratio of the dry lubricant is less than 0.05%, the positive electrode mixture powder has low lubricity and cannot be uniformly weighed, and the handling property of the positive electrode mixture 5 is significantly reduced. is there. On the other hand, if the blending ratio of the fluororesin powder exceeds 5%, the amount of active material that can be filled has to be reduced accordingly, which is not preferable.

Next, the effect of the present invention was verified by conducting an example in which the conductive agent and the dry lubricant in the positive electrode mixture described above were changed in type and mixing ratio.
(Example 1)
In the battery structure shown in FIG. 1, the negative electrode can 3 is made of a 0.15 mm thick clad material composed of a nickel outer surface layer S1, a metal layer S2 made of stainless steel (SUS), and a current collector layer S3 made of copper. Molded by press working.

  The positive electrode mixture 5 is composed of 20 mass% of silver / nickel composite oxide as a conductive agent, 1 mass% of fluorine resin powder as a dry lubricant, 74.5 mass% of nickel oxyhydroxide as a positive electrode active material, and as a binder. Resin powder 0.5 mass%, potassium hydroxide aqueous solution 2 mass% with a concentration of 37% as electrolyte, and aluminum hydroxide powder 1 mass% and calcium hydroxide powder 1 mass% as a thermal decomposition inhibitor of nickel oxyhydroxide were mixed in a blender. Then, it shape | molded in the pellet form with the tableting machine.

Next, the positive electrode mixture 5 is inserted into the positive electrode can 2 and an alkaline electrolyte containing potassium hydroxide is injected to cause the positive electrode mixture 5 to absorb the alkaline electrolyte.
On this positive electrode mixture 5, a separator 6 punched into a circular shape having a two-layer structure of a microporous membrane and a nonwoven fabric is loaded. The loaded separator 6 is impregnated with an alkaline electrolyte containing 37% aqueous potassium hydroxide solution.

On this separator 6, zinc alloy powder 61 mass%, zinc oxide 2.68 mass%, highly-crosslinked polysodium acrylate 1.43 mass% as active material stabilizer, non-crosslinked polysodium acrylate 0.05 mass%, and carboxy A gel-like negative electrode mixture 7 consisting of 1.47 mass% of methylcellulose and 33.37 mass% of 45% aqueous potassium hydroxide solution as an electrolytic solution is placed. And the negative electrode can 3 and the positive electrode can 2 were sealed by crimping, and the flat alkaline primary battery 1 was produced. At this time, a gasket 4 is sandwiched between the positive electrode can 2 and the negative electrode can 3 to improve the sealing performance.
(Example 2)
In Example 2, the same configuration as in Example 1 was used, but the average particle size of the silver / nickel composite oxide blended in the positive electrode mixture 5 as a conductive agent was changed from 10 μm to 1 μm.
(Example 3)
In Example 3, the same configuration as in Example 1 was used, but the average particle diameter of the silver / nickel composite oxide blended in the positive electrode mixture 5 as a conductive agent was changed from 10 μm to 20 μm.
Example 4
Example 4 has the same configuration as that of Example 1, but the mixing ratio of the silver / nickel composite oxide added to the positive electrode mixture 5 as a conductive agent is changed from 20 mass% to 5 mass%, and oxywater as a positive electrode active material Nickel oxide was changed from 74.5 mass% to 89.5 mass%.
(Example 5)
Example 5 has the same configuration as that of Example 1, but the mixing ratio of the silver / nickel composite oxide compounded as the conductive agent in the positive electrode mixture 5 is changed from 20 mass% to 30 mass%, and oxywater as the positive electrode active material Nickel oxide was changed from 74.5 mass% to 64.5 mass%.
(Example 6)
In Example 6, the same configuration as in Example 1 was used, but the average particle size of the fluororesin blended in the positive electrode mixture 5 as a lubricant was changed from 0.3 μm to 0.1 μm.
(Example 7)
In Example 7, the same configuration as in Example 1 was used, but the average particle diameter of the fluororesin blended in the positive electrode mixture 5 as a lubricant was 0.3 μm to 10 μm.
(Example 8)
Example 8 is configured in the same manner as in Example 1, but the blending ratio of the fluororesin blended in the positive electrode mixture 5 as a lubricant is changed from 1.0 mass% to 0.1 mass%, and oxywater as a positive electrode active material Nickel oxide was changed from 74.5 mass% to 75.4 mass%.
Example 9
Example 9 has the same configuration as that of Example 1, but the mixing ratio of the fluororesin compounded as a lubricant in the positive electrode mixture 5 is changed from 1.0 mass% to 3.0 mass%, and oxywater as a positive electrode active material Nickel oxide was changed from 74.5 mass% to 72.5 mass%.
(Comparative Example 1)
In Comparative Example 1, the same configuration as in Example 1 was used, but the conductive agent blended in the positive electrode mixture 5 was graphite having an average particle diameter of 10 μm.
(Comparative Example 2)
In Comparative Example 2, the same configuration as in Example 1 was used, but the average particle size of the silver / nickel composite oxide blended in the positive electrode mixture 5 as a conductive agent was changed from 10 μm to 0.5 μm.
(Comparative Example 3)
In Comparative Example 3, the same structure as in Example 1 was used, but the average particle size of the silver / nickel composite oxide blended in the positive electrode mixture 5 as a conductive agent was changed from 10 μm to 30 μm.
(Comparative Example 4)
Comparative Example 4 has the same configuration as that of Example 1, but the mixing ratio of the silver / nickel composite oxide compounded as the conductive agent in the positive electrode mixture 5 is changed from 20 mass% to 3 mass%, and oxywater as the positive electrode active material. Nickel oxide was changed from 74.5 mass% to 91.5 mass%.
(Comparative Example 5)
In Comparative Example 5, the same configuration as in Example 1 was used, but the lubricant compounded in the positive electrode mixture 5 was molybdenum disulfide having an average particle diameter of 1 μm.
(Comparative Example 6)
Comparative Example 6 has the same configuration as that of Example 1, but the average particle size of the fluororesin blended as the lubricant blended with the positive electrode mixture 5 was changed from 0.3 μm to 15 μm.
(Comparative Example 7)
Comparative Example 7 has the same configuration as that of Example 1, but the blending ratio of the fluororesin blended in the positive electrode mixture 5 as a lubricant was changed from 1.0 mass% to 0.05 mass%, and oxywater as a positive electrode active material Nickel oxide was changed from 74.5 mass% to 95.45 mass%.
(Comparative Example 8)
Comparative Example 8 has the same configuration as that of Example 1, but the blending ratio of the fluororesin blended in the positive electrode mixture 5 as a lubricant was changed from 1.0 mass% to 5.0 mass%, and oxywater as the positive electrode active material. Nickel oxide was changed from 74.5 mass% to 90.45 mass%.

Then, 40 alkaline batteries of Examples 1 to 9 and Comparative Examples 1 to 8 described above were produced, respectively, and the following verification was performed.
Specifically, Table 1 shows the discharge capacity [mAh] when each of these 20 batteries is subjected to a constant resistance discharge at 30 kΩ to a final voltage of 1.2V.

  Next, the discharge capacity [mAh] when these 20 batteries were stored at a temperature of 60 ° C. in a humidity dry environment for 100 days and then subjected to a constant resistance discharge at 30 kΩ to a final voltage of 1.2 V is shown in Table 1. Shown in

  Finally, Table 1 shows the results of evaluating the handling properties of each positive electrode mixture before producing 40 batteries.

（１）はじめに、この表１より、実施例１〜９と比較例１及び５とを比較するに、正極合剤５の導電剤として銀・ニッケル複合酸化物、乾性潤滑剤としてフッ素樹脂粉末を用いることにより、正極合剤５のハンドリング性に優れ、容量および容量保存性に優れた電池を得ることができる。

(1) First, from Table 1, in order to compare Examples 1 to 9 and Comparative Examples 1 and 5, silver / nickel composite oxide as the conductive agent of the positive electrode mixture 5, and fluororesin powder as the dry lubricant. By using it, a battery excellent in handling property of the positive electrode mixture 5 and excellent in capacity and capacity storage can be obtained.

  This is because the silver / nickel composite oxide has an excellent conductivity and is an active material having a mass energy density higher than that of silver oxide, and also has a binding property. This is because the addition to 5 can prevent the problem that the electronic conductivity is lowered due to the electrolytic solution absorption of nickel oxyhydroxide and the volume expansion associated with the discharge, and the capacity and capacity preservation are significantly lowered.

  In addition, the fluororesin powder is such that when the positive electrode mixture 5 is nickel oxyhydroxide and silver / nickel composite oxide alone, the lubricity as a powder is poor and the weighing property when processing into a pellet shape is significantly reduced. This is because it can be prevented with excellent lubricity.

  (2) Next, according to Table 1, in order to compare Examples 2 and 3 with Comparative Examples 2 and 3, the conductive agent of the positive electrode mixture 5 is a silver / nickel composite oxide, and the average particle diameter is 1 μm. As described above, by setting the thickness to 20 μm or less, it is possible to obtain a battery excellent in handling property of the positive electrode mixture 5 and excellent in capacity storage.

  This is because the conductive agent of the positive electrode mixture 5 is made of silver / nickel composite oxide, and the average particle diameter is 1 μm or more, so that the high conductivity and binding force of the silver / nickel composite oxide can be efficiently utilized. This is because the electron conductivity as the positive electrode mixture 5 can be improved and the volume expansion associated with the absorption and discharge of the nickel oxyhydroxide electrolyte can be suppressed.

  In addition, when the average particle diameter of the silver / nickel composite oxide is less than 1 μm, the binding property is lowered due to deterioration of the compressibility of nickel oxyhydroxide itself, which is not preferable. On the other hand, when the average particle diameter of the silver / nickel composite oxide exceeds 20 μm, the conductivity of nickel oxyhydroxide is lowered, which is not preferable.

  (3) Next, according to Table 1, in order to compare Examples 4 and 5 and Comparative Example 4, the conductive agent of the positive electrode mixture 5 is a silver / nickel composite oxide, and the blending ratio is 5 mass% or more, By setting it to 30 mass% or less, it is possible to obtain a battery excellent in handling property of the positive electrode mixture 5 and in capacity and capacity storage.

  This is because the mixing ratio of the silver / nickel composite oxide to the positive electrode mixture 5 is 5 mass% or more and 30 mass% or less, so that the positive electrode mixture 5 has high conductivity and binding power of the silver / nickel composite oxide. This is because it is possible to improve the electron conductivity as well as to suppress the volume expansion associated with the absorption and discharge of the nickel oxyhydroxide electrolyte.

  In addition, when the compounding ratio of the silver / nickel composite oxide to the positive electrode mixture 5 is less than 5 mass%, sufficient conductivity as the positive electrode mixture 5 and volume expansion associated with electrolyte absorption and discharge can be suppressed. It is not preferable because it disappears.

  On the other hand, if the blending ratio exceeds 30 mass%, the increase in conductivity of the positive electrode mixture 5 and the suppression of volume expansion associated with the absorption and discharge of the electrolytic solution increase the cost despite the fact that there is almost no merit in battery characteristics.

  (4) Next, according to Table 1, when Example 1 and Comparative Example 5 are compared, silver / nickel composite oxide is used as the conductive agent of the positive electrode mixture 5, and fluororesin powder is used as the dry lubricant. In addition, it is possible to obtain a battery excellent in handling property of the positive electrode mixture 5 and excellent in capacity and capacity storage.

  This is also a positive electrode mixture because the silver / nickel composite oxide has an excellent conductivity and is an active material having a mass energy density higher than that of silver oxide, and also has a binding property. This is because, by adding to the electrolyte, it is possible to prevent the problem that the electronic conductivity is lowered due to the electrolyte expansion of the nickel oxyhydroxide and the volume expansion associated with the discharge, and the capacity and capacity preservation are significantly reduced.

  In addition, the fluororesin powder is excellent in that the positive electrode mixture is nickel oxyhydroxide and silver / nickel composite oxide alone, and the lubricity as a powder is poor and the weighability when processing into a pellet shape is significantly reduced. This is because it can be prevented by the lubricity.

  In addition, when molybdenum disulfide is used as the dry lubricant of the positive electrode mixture 5, it is surmised that the capacity and capacity storage were significantly reduced because corrosion of zinc in the negative electrode was accelerated by the presence of molybdenum.

  (5) Next, according to Table 1, when comparing Examples 6 and 7 with Comparative Example 6, the average particle size of the fluororesin powder as a dry lubricant of the positive electrode mixture 5 is 0.1 μm or more and 10 μm or less. By doing so, a positive electrode mixture excellent in handling properties can be obtained.

  This is because when the average particle size of the fluororesin powder is 0.1 μm or more and 10 μm or less, the excellent lubricity of the fluororesin powder can be efficiently utilized. This is because the weighing property can be improved.

  In addition, it is difficult to manufacture industrially such that the average particle size of the fluororesin powder is less than 0.1 μm with the current technology. Also, if the average particle size exceeds 10 μm, the lubricity per unit mass of the fluororesin powder will be reduced, and the blending ratio to the positive electrode mixture will have to be increased, and the amount of active material that can be filled is reduced accordingly. Must be unfavorable.

  (6) Next, according to Table 1, in order to compare Examples 8 and 9 and Comparative Examples 7 and 8, the compounding ratio of the fluororesin powder as a dry lubricant of the positive electrode mixture 5 is 0.05 mass% or more, By setting it to 5 mass% or less, it is possible to obtain a battery excellent in handling property of the positive electrode mixture 5 and excellent in capacity.

  This is because, since the fluororesin powder has excellent lubricity, the positive electrode mixture 5 can be obtained with improved handling properties by improving the weighability of the positive electrode mixture 5 even in a low amount of the positive electrode mixture 5. It is. In addition, since the fluororesin powder has water repellency, the fluororesin powder does not swell due to absorption of the electrolytic solution, and has an effect of reducing the conductive agent blending ratio in the positive electrode mixture 5. As a result, a battery having an excellent capacity can be obtained.

  If the blending ratio of the fluororesin powder is less than 0.05 mass%, the lubricity of the positive electrode mixture powder is lowered and uniform weighing cannot be performed, and the handling property of the positive electrode mixture is remarkably lowered. On the other hand, if the blending ratio of the fluororesin powder exceeds 5 mass%, the amount of active material that can be filled has to be reduced accordingly, which is not preferable.

Next, effects of the present embodiment configured as described above will be described below.
(1) According to this embodiment, the flat alkaline primary battery 1 uses zinc or a zinc alloy powder as a negative electrode active material, and has a noble potential relative to manganese dioxide or silver oxide as a positive electrode active material. Since nickel hydroxide was used, a higher battery voltage could be obtained than alkaline manganese batteries and silver oxide batteries.

  In addition, since silver / nickel composite oxide was used as the conductive agent for the positive electrode mixture and fluororesin powder was used as the dry lubricant, the volume associated with electrolyte absorption and discharge due to the high conductivity and binding power of the silver / nickel composite oxide. Expansion of the battery can be suppressed, a decrease in electronic conduction due to volume expansion of the positive electrode can be prevented, and a battery excellent in capacity and capacity storage can be obtained.

  Moreover, the positive electrode mixture 5 excellent in handling property can be obtained by improving the weighability of the positive electrode mixture 5 by the lubricity of the fluororesin powder as a dry lubricant. Therefore, the flat alkaline primary battery 1 can withstand use for a long time in a device such as an electronic wristwatch whose end voltage is set higher in accordance with the battery voltage of the silver oxide battery.

  Moreover, since the flat alkaline primary battery 1 of the present embodiment uses an expensive material (silver) in a low blending like the silver oxide primary battery, it can be manufactured at a low cost without being greatly influenced by the precious metal market.

  (2) According to the present embodiment, the flat alkaline primary battery 1 has the conductive agent of the positive electrode mixture 5 made of silver / nickel composite oxide and the average particle size of 1 μm or more and 20 μm or less. A battery excellent in handling property of the agent 5 and excellent in capacity and capacity storage can be obtained.

  (3) According to the present embodiment, the flat alkaline primary battery 1 is composed of a silver / nickel composite oxide as the conductive agent of the positive electrode mixture 5, and the blending ratio thereof is 5 mass% or more and 30 mass% or less. A battery excellent in the handling property of the mixture 5 and excellent in capacity and capacity storage can be obtained.

  (4) According to the present embodiment, the flat alkaline primary battery 1 has excellent handling properties because the average particle size of the fluororesin powder is 0.1 μm or more and 10 μm or less as the dry lubricant of the positive electrode mixture 5. The positive electrode mixture 5 can be obtained.

  (5) According to the present embodiment, the flat alkaline primary battery 1 has a positive electrode composition by adjusting the blending ratio of the fluororesin powder as a dry lubricant of the positive electrode mixture 5 to 0.05 mass% or more and 5 mass% or less. A battery having excellent handling properties of the agent 5 and excellent capacity can be obtained.

The schematic sectional drawing of the alkaline battery of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Alkaline battery, 2 ... Positive electrode can, 3 ... Negative electrode can, 4 ... Gasket, 5 ... Positive electrode mixture, 6 ... Separator, 7 ... Negative electrode mixture.

Claims (5)

The opening of the negative electrode can is fitted into the opening of the positive electrode can, and the separator is placed in a sealed space in which the positive electrode can and the negative electrode can are sealed with a gasket. A positive electrode mixture mainly composed of an active material is arranged, a negative electrode mixture mainly composed of a negative electrode active material is arranged on the negative electrode side, and the positive electrode mixture, separator and negative electrode mixture are further arranged in a sealed space. A flat alkaline primary battery filled with an alkaline electrolyte,
Zinc or zinc alloy powder is used as the negative electrode active material, nickel oxyhydroxide is used as the positive electrode active material, a silver / nickel composite oxide is used as a conductive agent for the positive electrode mixture, and a fluorine resin is used as a dry lubricant for the positive electrode mixture. A flat alkaline primary battery comprising a powder. The flat alkaline primary battery according to claim 1,
The flat alkaline primary battery, wherein the silver / nickel composite oxide has an average particle diameter of 1 to 20 μm. The flat alkaline primary battery according to claim 1 or 2,
A flat alkaline primary battery, wherein a compounding ratio of the silver / nickel composite oxide in the positive electrode mixture is 5 mass% or more and 30% or less. The flat alkaline primary battery according to any one of claims 1 to 3,
The flat alkaline primary battery, wherein the fluororesin powder has an average particle size of 0.1 to 10 μm. In the flat alkaline primary battery according to any one of claims 1 to 4,
A flat alkaline primary battery, wherein a blending ratio of the fluororesin powder in the positive electrode mixture is 0.05 mass% or more and 5 mass% or less.

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