JP6548417B2 - Flat alkaline primary battery - Google Patents

Description

The present invention relates to a flat alkaline primary battery.

A coin-shaped or button-shaped flat alkaline primary battery is widely used as a power source for small electronic devices such as electronic watches and portable electronic computers.
As this flat alkaline primary battery, an alkaline button battery using manganese dioxide as a positive electrode, gelled zinc powder as a negative electrode, a silver oxide battery using silver oxide as a positive electrode, a gelled zinc powder as a negative electrode, etc. are known. There is.

  The gelled negative electrode mixture used in these batteries is obtained by adding a thickener for controlling the viscoelasticity to an electrolyte comprising zinc powder, zinc oxide and an aqueous alkaline solution. . At the time of assembly of the battery, the negative electrode mixture is discharged from a dispenser and filled on the separator contained in the positive electrode can and the inside of the negative electrode can. The ease of discharge of the negative electrode mixture and the stability of the filling amount (hereinafter referred to as handling property) can be adjusted by the addition amount of the thickener in the negative electrode mixture.

  As a thickener, carboxymethylcellulose (hereinafter referred to as CMC), sodium polyacrylate (hereinafter referred to as PAS), and the like are known (see, for example, Patent Document 1 and Patent Document 2). CMC is a kind of cellulose-based water-soluble polymer and is a substance having a high viscosity, and thus is widely used for gelation of a negative electrode mixture. Moreover, it is disclosed also about the thickener used by mixing CMC and PAS in the same amount grade (for example, refer patent document 3).

JP, 2010-44906, A Unexamined-Japanese-Patent No. 2013-235654 JP, 2009-211841, A

  However, CMC is a material that has a range of viscosities from lot to lot. Therefore, when a certain amount is added to the aqueous solution of the negative electrode mixture, the viscosity varies. If the viscosity of the negative electrode mixture is too high (if too much CMC is added) the mixture will solidify, while if the viscosity of the negative electrode mixture is too low (if too little CMC is added) it will be gel-like It disappears.

  That is, since the width of the appropriate CMC addition amount is too narrow, conventionally, a process for adjusting the thickener concentration by appropriately adjusting the aqueous solution of the negative electrode mixture or CMC is required each time. And increased costs.

  On the other hand, as in Patent Document 3, when CMC and PAS are mixed and used in the same amount, or when PAS alone is used as a thickener, PAS has higher viscoelasticity than CMC and adjustment of viscosity Problems will become more difficult.

As a result of intensive studies, the present inventors have found that adding a trace amount of PAS to CMC broadens the concentration range of the thickener capable of ensuring the handling property, and has led to the present invention.
That is, the present invention has the following configuration as means for solving the above problems.

The negative electrode mixture for flat-shaped alkaline primary battery according to claim 1 is a flat electrode mixture for flat-shaped alkaline primary battery containing zinc powder, zinc oxide powder, an alkaline aqueous solution, and a thickener, The thickener comprises carboxymethylcellulose and sodium polyacrylate, and the negative electrode mixture contains 2 to 5% by weight of the thickener, and the polyacrylic acid relative to the entire thickener. It is characterized in that it contains 3 to 15% by weight of sodium.
According to the first aspect of the present invention, by adding a small amount of PAS to CMC as a thickener, even when the concentration of the thickener is large, the negative electrode mixture can be maintained in a gel state without solidification. As a result, the process of separately adjusting the thickener concentration is not necessary regardless of the concentration variation of the CMC, and the manufacturing cost can be reduced.

The negative electrode mixture for a flat alkaline primary battery according to claim 2 is characterized in that the negative electrode mixture contains 1 to 25% by weight of an insulating powder.
According to the second aspect of the invention, by adding the insulating powder, the handling property of the negative electrode mixture can be improved even if the viscosity of the thickener varies.

The negative electrode mixture for a flat alkaline primary battery according to claim 3, wherein the insulating powder has an average particle diameter of 110 to 350 m.
According to the third aspect of the present invention, it is possible to suppress the measurement variation of the negative electrode mixture and to further improve the handling property of the negative electrode mixture.

The negative electrode mixture for a flat alkaline primary battery according to claim 4, wherein the insulating powder comprises one or more resin powders selected from polytetrafluoroethylene, polypropylene, polyamide, polyethylene and acrylic resin. It is characterized by
According to the invention as set forth in claim 4, the adhesion between the electrolytic solution and the thickener and the insulating powder is reduced by using such a material having excellent water repellency, and cutting of the negative electrode mixture at the time of weighing Thus, the handling of the negative electrode mixture can be further improved.

The flat alkaline primary battery according to claim 5 comprises a container comprising a positive electrode can, a negative electrode can and a gasket, a positive electrode mixture comprising silver oxide, manganese dioxide, a conductive additive and a hydrogen storage alloy. Item 5 is characterized in that it includes the negative electrode mixture according to any one of items 1 to 4, a separator, and an electrolytic solution made of an alkaline aqueous solution.
According to the fifth aspect of the present invention, the efficiency of producing the battery is increased by using the above-mentioned negative electrode mixture, so that the battery can be manufactured at low cost.

The method of manufacturing a flat alkaline primary battery according to claim 6 includes the steps of: housing a positive electrode mixture in a positive electrode can; mounting a separator on the positive electrode mixture; and pressing a gasket into the positive electrode can A process for producing a flat alkaline primary battery comprising the steps of: forming an anode mix on the separator; and caulking and sealing an opening edge of the anode can by covering the anode can. In the step of forming the negative electrode mixture on the separator, the negative electrode mixture according to any one of claims 1 to 4 is used.
According to the invention described in claim 6, by using the above-mentioned negative electrode mixture, the efficiency of producing a battery can be increased, and the production cost can be suppressed.

  According to the present invention, it is possible to provide a negative electrode mixture having a wide concentration range of thickener and excellent in handleability. As a result, the process of adjusting the thickener concentration is unnecessary, and the manufacturing cost can be reduced.

1 is a cross-sectional view of a flat alkaline primary battery showing an embodiment of the present invention.

Hereinafter, embodiments of a flat alkaline primary battery according to the present invention will be described using the drawings.
(Outline of flat alkaline primary battery)
The flat alkaline primary battery 1 shown in FIG. 1 is a button-type primary battery. The flat alkaline primary battery 1 includes, in a case 8, a positive electrode mixture 5, a separator 6, a negative electrode mixture 7, and an electrolytic solution composed of an alkaline aqueous solution.

  More specifically, the flat alkaline primary battery 1 is fixed to the bottom of the cylindrical positive electrode can 2 and the opening of the positive electrode can 2 via the gasket 4, and the sealed space S is interposed between It has the bottomed cylindrical negative electrode can 3 to form. Then, the opening 2 a of the positive electrode can 2 is crimped toward the gasket 4 and sealed to form a case 8 provided with a sealed space S. The positive electrode mixture 5, the separator 6, and the negative electrode mixture 7 are accommodated in the closed space S, and the positive electrode mixture 5 is disposed on the positive electrode can 2 side with the separator 6 interposed therebetween, and the negative electrode mixture 7 is disposed on the negative electrode can 3 side. It is done.

  The positive electrode can 2 is made of stainless steel (SUS) plated with nickel and is formed in a cup shape. The positive electrode can 2 accommodates the positive electrode mixture 5 and functions as a positive electrode terminal.

  The negative electrode can 3 is formed in a cup shape from a clad material of a three-layer structure having an outer surface layer made of nickel, a metal layer made of stainless steel (SUS), and a current collector layer made of copper. . Further, the negative electrode can 3 has the opening 3a folded back, and the gasket 4 is attached to the opening 3a.

  Then, the negative electrode can 3 is fitted to the circular opening 2 a of the positive electrode can 2 from the opening 3 a side to which the gasket 4 is attached, and the opening 2 a of the positive electrode can 2 is crimped toward the gasket 4 and sealed. Thus, a flat (button or coin) case 8 is formed. A sealed space S is formed inside the case 8.

  As shown in FIG. 1, the gasket 4 is formed in an annular shape along the inner peripheral surface of the positive electrode can 2 and has an annular groove. The annular groove is in contact with the opening 3 a of the negative electrode can 3. For example, nylon or the like is used for such a gasket 4 as a material.

  The separator 6 has a two-layer structure of a microporous film 6a and a non-woven fabric 6b. With this two-layer structure, the barrier property between the positive electrode and the negative electrode can be enhanced, and the storage capacity can be improved. In addition, since the alkaline electrolyte can be effectively held, the discharge characteristics can be improved. As the microporous film 6a, a polyethylene film, cellophane, graft polymerization film or the like can be used. In addition, as the non-woven fabric 6b, liquid absorbent paper made of cellulose can be used.

  When the flat alkaline primary battery 1 is assembled, the positive electrode mixture 5 formed into a pellet shape is filled in the positive electrode can 2. Then, the separator 6 is placed on the positive electrode can 2, and further, the gelled negative electrode mixture 7 is placed on the separator 6, and the negative electrode can 3 on which the gasket 4 is mounted is covered. Furthermore, the opening edge of the positive electrode can 2 is crimped to seal the case 8.

(Positive mix)
In the present embodiment, the positive electrode mixture 5 is made of a positive electrode active material, a conductive support agent, a binder and the like, and is formed into a pellet shape. By impregnating the pellet-shaped positive electrode mixture 5 with the electrolytic solution, an electrode reaction can be generated between the positive electrode active material and the electrolytic solution.

For example, materials such as silver oxide (Ag ₂ O), manganese dioxide (MnO ₂ ), and nickel oxyhydroxide (NiOOH) can be used as the positive electrode active material. Among them, silver oxide is a material having a very large theoretical capacity per unit mass and capable of stabilizing the output voltage of the flat alkaline primary battery 1 until the end of the discharge, and is preferably used. When the positive electrode active material is silver oxide, it is used in the form of granules of 75 to 300 μm formed from fine powder having a particle size of 5 to 15 μm. Alternatively, a mixture of silver oxide and manganese dioxide may be used as the positive electrode active material.

  As an additive, for example, a conductive auxiliary agent for improving conductivity is added to the positive electrode mixture 5. For example, graphite, graphite or the like is used as the conductive additive. The conductivity can be sufficiently improved if the additive amount is large. On the other hand, if the proportion of silver oxide in the positive electrode mixture 5 decreases even if the amount of the conductive additive is too large, the discharge capacity of the battery decreases, and furthermore, the density and strength of the pellets of the positive electrode mixture 5 decrease. Therefore, the conductive additive is preferably contained in the positive electrode mixture 5 in an amount of 1 to 5% by weight.

Further, to the positive electrode mixture 5 can be added a hydrogen storage alloy for absorbing hydrogen gas generated upon contact of the zinc powder in the negative electrode mixture 7 of the battery with the electrolytic solution. As the hydrogen storage alloy, LaNi-based alloys such as LaNi _5, Lm-Ni alloy (Lm is La enriched misch metal) AB5 type hydrogen storage alloy such as, AB2-type hydrogen storage alloy such as Ti, Mg alloys, Various materials such as a Ca-based alloy and a silver-nickel composite oxide (AgNiO ₂ ) can be used. Among these, LaNi ₅ is particularly preferable because of its extremely high hydrogen storage capacity. The hydrogen storage alloy can exhibit the above-mentioned hydrogen storage capacity if it is contained in an amount of 0.5 to 5% by weight in the positive electrode mixture 5. However, in order to keep the capacity of the battery high, it is preferable that 0.5 to 2% by weight of the positive electrode mixture 5 is contained so that the ratio of silver oxide does not decrease. An alloy powder of 10 to 50 μm is used as an embodiment of the hydrogen storage alloy.

  Further, as the binder, polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), polyacrylic acid (PA), carboxymethylcellulose (CMC), polyimide (PI), polyamide imide (PAI) and the like can be mentioned. It can use suitably as these 1 type, or 2 or more types of combination.

(Negative mix)
In the present embodiment, the negative electrode mixture 7 contains a negative electrode active material, a conductivity stabilizer, a thickener (gelling agent), and an electrolytic solution.
Zinc powder or zinc alloy powder is used as the negative electrode active material. Zinc oxide (ZnO) or the like is used as the conductivity stabilizer. As an electrolyte solution, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, or these mixed solutions can be used.

  Further, as the thickener, one obtained by adding sodium polyacrylate (PAS) in a minute amount to carboxymethylcellulose (CMC) is used. By using these thickeners, it is possible to improve the lyophilic property and the liquid retaining property of the negative electrode mixture 7 with respect to the electrolytic solution.

  CMC is one of cellulose-based water-soluble polymers, and is widely used in food additives, medicines, cosmetics, electronic materials and the like. This CMC has a structure in which a carboxymethyl group is bonded to a part of the hydroxy group of glucopyranose monomer constituting the skeleton of cellulose. CMC is a material with high viscosity, and the viscosity at 25 ° C. of a 1% by weight aqueous solution (hereinafter referred to as viscosity) is 10 to 10000 mPa · s depending on the degree of polymerization. In addition, the degree of water absorbency and gelation differ depending on the difference in the degree of substitution of the carboxymethyl group (the degree of etherification) per unit of anhydrous glucose. About these viscosity and etherification degree, it can select suitably according to a use.

  The CMC used in the present embodiment has a viscosity of 80 to 150 mPa · s and a grade of etherification of 0.85 to 0.95. The CMC is used in powder form, added to a negative electrode mixture containing an electrolytic solution, and adjusted to a viscosity suitable for use in the negative electrode mixture.

  In addition, PAS is one of the highly water-absorbing polymers, and is a thickener widely used in paints, cosmetics and the like. It is known that this PAS has a network structure containing a large amount of carboxyl groups in the molecule, so that its viscosity is as high as that of CMC. On the other hand, the aqueous solution of PAS is a liquid with high viscosity, and has a property of being less likely to become gel like CMC. Therefore, it is difficult to use the gel as a gelling agent for the negative electrode mixture 7 of the alkaline primary battery in the present invention alone because the viscosity adjustment is difficult. Therefore, as a thickener of the conventional negative electrode mixture 7, it was usual to use CMC alone.

  However, in the case of a thickener with CMC alone, the viscosity varies from lot to lot due to the variation in viscosity within the above range. If the viscosity of the negative electrode mixture 7 is too high, there is a problem that the mixture solidifies. Therefore, conventionally, it has been necessary to separately perform a process of adjusting the viscosity by adjusting the addition amount of CMC.

  In this embodiment, by adding a small amount of PAS to CMC, even if the concentration of the whole thickener is increased, good handling is maintained without solidifying like a thickener of CMC alone. can do. Specifically, the content ratio of the total of CMC and PAS in the negative electrode mixture 7 is 2% by weight or more and 5% by weight or less, and the mixing ratio of PAS in the thickener (the total of CMC and PAS) Is preferably 3% by weight or more and 15% by weight or less. If it is the content rate of this thickener, it can be set as the favorable negative electrode mixture 7 of handling property.

  And by setting it as the mixing | blending ratio of said PAS, even if it is a case where the density | concentration of the whole thickener is high by adding a trace amount, it does not solidify like the thickener only of CMC, and is favorable. Good handling can be maintained.

  On the other hand, when the content ratio of PAS is too small, the mixture is solidified when the viscosity of the negative electrode mixture 7 becomes high due to the dispersion of the viscosity of CMC, as in the case of the thickener of CMC alone. Moreover, when the content ratio of PAS is too large, the viscosity of the negative electrode mixture 7 becomes too low, and the handling property is significantly reduced.

  Moreover, in order to improve the viscoelasticity of the negative electrode mixture 7, a viscoelasticity adjusting material can be further added. The viscoelastic modifier is preferably a nonmetallic insulating powder that does not react with the strongly alkaline electrolyte. For example, resin powder consisting of one or more selected from polytetrafluoroethylene, polypropylene, polyamide, polyethylene, acrylic resin and the like can be used as the viscoelasticity adjusting material, and polyethylene is particularly easy to handle, and in particular preferable. These resin powders may have a particle diameter of 110 to 350 μm. Moreover, when adding to the negative electrode mixture 7, it is preferable if 1 to 25 weight% is added in the negative electrode mixture 7 whole.

When assembling the flat alkaline primary battery 1, the negative electrode mixture 7 in the present embodiment is placed on the separator 6 as described below.
First, the negative electrode mixture 7 is filled with a dispenser into a cylindrical cut-off scraping plate. Next, the dispenser is moved horizontally to fill the holes of the scraping plate with the negative electrode mixture 7. After that, prepare the positive electrode can 2 containing the positive electrode mixture 5 and the separator 6 in the lower part of the hole of the stamped plate, and push the hollow supply rod from above to put the gelled negative electrode mixture 7 on the separator 6. Place and supply. Finally, air is supplied from the hollow portion of the feed rod to separate the feed rod and the negative electrode mixture 7 from each other.

  At that time, if the viscosity is too high due to the concentration of the thickener as a whole being high, the negative electrode mixture 7 will not fill up to every corner of the hole of the imprinting plate and the filling property will deteriorate. On the other hand, when the concentration of the thickener as a whole is small and the viscosity is too low, the mounting shape of the negative electrode mixture 7 after the printing is deteriorated.

  In addition, when the binding strength of the negative electrode mixture 7 itself is weak because the proportion of PAS in the thickener is weak, the shape of the negative electrode mixture 7 itself is broken by air supplied from the supply rod (destruction air). On the other hand, when the proportion of PAS in the thickener is too large and the stickiness of the negative electrode mixture 7 is large, the negative electrode mixture 7 becomes difficult to separate from the supply crucible, and the negative electrode mixture 7 on the separator 6 is displaced.

Next, a negative electrode mixture 7 in which the content ratio of the thickener (CMC and PAS) is variously changed is manufactured as in Examples 1 to 4 and Comparative Examples 1 to 4 shown below, and the effects of the present invention are verified did.
Example 1
In this example, a negative electrode mixture 7 used for a flat alkaline primary battery was produced as follows.
Specifically, 66% by weight of zinc alloy powder having an average particle diameter of 150 μm, 3% by weight of zinc oxide (ZnO), 1.94% by weight of carboxymethylcellulose (CMC), respectively, with respect to the total weight of the negative electrode mixture 7 A gel-like negative electrode mixture 7 was produced by blending and mixing so as to be 29% by weight of sodium hydroxide aqueous solution containing sodium acrylate (PAS) 0.06 and a concentration of 28%.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 2.00%, and the content ratio of PAS to the whole thickener was 3% by weight.

(Example 2)
The composition is different from Example 1 only in that it is blended so that 1.70 wt% of CMC, 0.30 wt% of PAS, and 29 wt% of sodium hydroxide aqueous solution with respect to the total weight of the negative electrode mixture 7 are different. The same as in Example 1.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 2.00%, and the content ratio of PAS to the whole thickener was 15% by weight.

(Example 3)
The composition is different from Example 1 only in that CMC is mixed to 4.85 wt%, PAS to 0.15 wt%, and sodium hydroxide aqueous solution 26 wt% with respect to the total weight of the negative electrode mixture 7. The same as in Example 1.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 5.00%, and the content ratio of PAS to the whole thickener was 3% by weight.

(Example 4)
The only difference is that the composition is 4.25 wt% of CMC, 0.75 wt% of PAS, and 26 wt% of aqueous sodium hydroxide solution with respect to the total weight of the negative electrode mixture 7, the other constitution is different from that of Example 1 The same as in Example 1.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 5.00%, and the content ratio of PAS to the whole thickener was 15% by weight.

(Comparative example 1)
The composition is different from Example 1 only in that 0.95 wt% of CMC, 0.05 wt% of PAS, and 30 wt% of sodium hydroxide aqueous solution are blended with respect to the total weight of the negative electrode mixture 7. The same as in Example 1.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 1.00%, and the content ratio of PAS to the whole thickener was 5% by weight.

(Comparative example 2)
The composition is different from Example 1 only in that it is blended so that 5.70 wt% of CMC, 0.30 wt% of PAS, and 25 wt% of a sodium hydroxide aqueous solution with respect to the total weight of the negative electrode mixture 7 are different. The same as in Example 1.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 6.00%, and the content ratio of PAS to the whole thickener was 5% by weight.

(Comparative example 3)
The only difference is that the composition is such that 3.00 wt% of CMC and 28 wt% of a sodium hydroxide aqueous solution with respect to the total weight of the negative electrode mixture 7 and the PAS is not blended, and the other constitution is different from that of Example 1 Same as.

(Comparative example 4)
The composition is different from Example 1 only in that CMC is compounded 2.49% by weight, PAS is 0.51% by weight, and sodium hydroxide aqueous solution is 28% by weight with respect to the total weight of the negative electrode mixture 7. The same as in Example 1.
At this time, the ratio of the whole thickener (the sum of CMC and PAS) to the total weight of the negative electrode mixture 7 was 3.00%, and the content ratio of PAS to the whole thickener was 17% by weight.

(Evaluation)
And about the negative electrode mixture 7 of Examples 1-4 and Comparative Examples 1-4, the filling property, the mounting shape to a separator, and the mounting property were evaluated by the method shown next.
(Evaluation 1: Fillability)
The negative electrode mixture 7 of each of the examples and the comparative examples was filled with a weighing cylindrical hole for scraping with a dispenser, and it was visually observed whether or not it was completely filled. It was regarded as pass (indicated by ○) when filled up to every corner, and rejected (indicated by x) when a gap was observed between the negative electrode mixture 7 and the hole for abrasion.

(Evaluation 2: Mounting shape)
The negative electrode mixture 7 scraped off with the scraping plate used in Evaluation 1 was placed on the separator 6 used in the battery, and at that time, it was visually observed whether or not the cylindrical shape was maintained. When the cylindrical shape was maintained, it was accepted (indicated by)), and the one whose shape was broken due to destructive air at the time of supply was rejected (indicated by ×). In addition, the comparative example which could not be evaluated is represented by "-".

(Evaluation 3: Mounting)
The negative electrode mixture 7 of each example and comparative example placed on the separator 6 in the evaluation 2 was visually observed whether it was placed at the center of the separator 6. When the negative electrode mixture 7 was placed at the center of the separator 6, it passed (denoted by ○), and when it was deviated from the center, it was rejected (denoted by x). In addition, the comparative example which could not be evaluated is represented by "-".
(Evaluation results)
The evaluation results of Evaluations 1 to 3 are shown in Table 1.

In Examples 1 to 4, good results were shown in any evaluation items of the packing property, the mounting shape, and the mounting property.
On the other hand, in Comparative Example 1 in which the concentration of the whole thickener was small, the filling property was good, but the mounting shape and the mounting property were both rejected. This is because the negative electrode mixture was too soft due to the presence of too little thickener, and the cylindrical shape after abrasion could not be maintained and collapsed. In addition, the negative electrode mixture is sticky and has poor mounting properties.

  Moreover, in Comparative Example 2 in which the concentration of the thickener as a whole is large, the filling property was deteriorated, and it was not possible to evaluate the mounting shape and the mounting property thereafter. This is because the amount of the thickener is too large and the negative electrode mixture becomes hard.

  In addition, in Comparative Example 3 in which the proportion of PAS in the thickener is small, the filling property is good, but the binding ability of the negative electrode mixture itself is weak, and the shape is broken by destructive air when placed. The mounting shape was not acceptable. As a result, it was not possible to evaluate the mountability.

  Moreover, in the comparative example 4 in which the ratio of PAS in a thickener is large, although the filling property and the mounting shape were favorable, the mounting property was rejection. This is because the stickiness of the negative electrode mixture increased, and the separation from the supply crucible at the time of mounting on the separator became worse.

  From the results of the examples described above, by adopting the thickener specified in the present invention, even if the concentration variation of CMC occurs, the handling property of the negative electrode mixture is improved without performing the concentration adjustment process. It can be done.

DESCRIPTION OF SYMBOLS 1 flat-shaped alkaline primary battery 2 positive electrode can 3 negative electrode can 4 gasket 5 positive electrode mixture 6 separator 7 negative electrode mixture 8 case

Claims (4)

A positive electrode mixture comprising silver oxide, manganese dioxide, a conductive additive, and a hydrogen storage alloy;
Zinc powder, zinc oxide powder, and an alkaline aqueous solution, a flat alkaline primary battery comprising a negative electrode mixture containing a thickening agent, a
The thickener comprises carboxymethylcellulose and sodium polyacrylate,
5 % by weight of the thickener is contained in the negative electrode mixture, and 3 to 15% by weight of the sodium polyacrylate is contained with respect to the whole of the thickener. batteries. The negative electrode material mixture flat alkaline primary battery according to claim 1, characterized in that it comprises 1 to 25% by weight of insulating powder in. The insulating powder is flat alkaline primary battery according to claim 2, wherein the average particle size of 110～350Myuemu. The flat alkaline primary battery according to claim 2 or 3, wherein the insulating powder comprises one or more resin powders selected from polytetrafluoroethylene, polypropylene, polyamide, polyethylene and acrylic resin. pond.

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