JP6130012B2 - Flat primary battery, negative electrode mixture for flat primary battery, and method for producing the same - Google Patents

Description

  The present invention relates to a flat primary battery, a negative electrode mixture for a flat primary battery, and a method for producing the same.

  Flat-type primary batteries such as coin-type or button-type used in small electronic devices such as electronic watches and portable electronic computers are becoming more powerful and cheaper as the performance of smaller electronic devices becomes higher and lower. In addition, there is a need for improved productivity.

  As this flat primary battery, an alkaline button battery using manganese dioxide for the positive electrode and gelled zinc powder for the negative electrode, a silver oxide battery using silver oxide for the positive electrode and gelled zinc powder for the negative electrode, etc. are known. . These batteries are formed by caulking a positive electrode can filled with a positive electrode mixture and a negative electrode can filled with a negative electrode mixture via a separator.

  In this flat primary battery, the ratio of the active material in the positive electrode mixture and the negative electrode mixture is adjusted according to the electric capacity required for each battery size. In a gelled negative electrode mixture using zinc or a zinc alloy, the ratio of the active material is adjusted by including a nonmetallic insulating powder that does not react with the electrolytic solution (for example, Patent Document 1).

JP 2010-044906 A

  However, in a gelled negative electrode mixture using zinc or a zinc alloy, when the particle size of the nonmetallic insulating powder that does not react with the electrolyte is small, this insulation is applied to the supply pin when the negative electrode mixture is molded. There was a problem that the negative electrode mixture could not be normally supplied due to the adhering powder.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a flat primary battery capable of improving productivity, a negative electrode mixture for a flat primary battery, and a method for producing the same. It is in.

The present invention has the following configuration as means for solving the above problems.
A negative electrode mixture for a flat primary battery according to the present invention includes a negative electrode active material, a conductivity stabilizer, a gelling agent, an electrolytic solution, and a viscoelasticity adjusting material. The negative electrode active material is zinc powder or zinc alloy powder having an average particle size of 50 μm or more and 250 μm, and the viscoelasticity adjusting material is an average particle size of 110 μm or more and 350 μm or less and an average particle of the negative electrode active material One or a plurality of resin powders of polytetrafluoroethylene, polyamide, polyethylene and acrylic resin having a diameter of 60% to 140% , and contained in the negative electrode mixture in an amount of 1% by volume to 25% by volume. It is characterized by that.
The flat primary battery according to the present invention is characterized by using the above negative electrode mixture.
Furthermore, the method for producing a flat primary battery according to the present invention includes a step of filling a positive electrode can with a positive electrode mixture, laying a separator on the positive electrode mixture, and press-fitting a gasket; It comprises the steps of placing the negative electrode mixture, covering the negative electrode can, and crimping and sealing the opening edge of the positive electrode can.
According to this configuration, in addition to the gelling agent, non-metallic insulating powder that does not react with the electrolyte solution is blended, so that the viscoelasticity of the negative electrode mixture can be suitably adjusted even if the ratio of the gelling agent is increased. Can do. Moreover, since the average particle diameter of the viscoelasticity adjusting material is 60% to 140% of the average particle diameter of the negative electrode active material which is zinc powder or zinc alloy powder having an average particle diameter of 50 μm or more and 250 μm , and is 110 μm or more, Variation in weighing of the negative electrode mixture can be suppressed.
In addition, since the average particle size of the viscoelasticity adjusting agent is 350 μm or less, even when the ratio of this viscoelasticity adjusting agent is increased, it is less likely to adhere to the supply pin when molding the negative electrode mixture, Productivity of the flat primary battery can be improved.
Further, the viscoelasticity adjusting agent is a water-repellent polytetrafluoroethylene, polyamide, polyethylene, or acrylic resin, and any one or a plurality of resin powders. Even if the ratio of the acid or a mixture thereof is increased, the viscoelasticity of the negative electrode mixture can be suitably adjusted to the viscoelasticity that provides good handling properties.
Furthermore, since the viscoelasticity adjusting agent is contained in the negative electrode mixture in an amount of 1% by volume to 25% by volume, good handling properties can be obtained while maintaining the electric capacity of the battery at the required capacity.
With the configuration described above, it is possible to improve the handling property and productivity in the battery assembly process while suppressing the electric capacity of the battery to the required capacity, and to suppress variations in the electric capacity.

In the negative electrode mixture for flat primary batteries according to the present invention, the gelling agent includes carboxymethyl cellulose, polyacrylic acid, or a mixture thereof.
According to this configuration, it is possible to suitably adjust the viscoelasticity of the negative electrode mixture.

The flat primary battery of the present invention, the negative electrode mixture for a flat primary battery, and the method of manufacturing a flat primary battery have the handling and productivity in the battery assembly process while maintaining the electric capacity of the battery at the required capacity. Can be improved.

FIG. 1 is a cross-sectional view of a flat alkaline primary battery. FIG. 2 is a schematic diagram showing the effect on productivity when the average particle size of the insulating powder is 110 μm or less. FIG. 3 is a table of examples and comparative examples.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIG.
FIG. 1 is a schematic cross-sectional view of a flat alkaline primary battery in which a positive electrode mixture, a negative electrode mixture, and an electrolytic solution are accommodated in a flat case. In FIG. 1, a flat alkaline primary battery 1 is a button-type primary battery, and includes a positive electrode can 2 and a negative electrode can 3. The positive electrode can 2 is made of a material obtained by applying nickel plating to stainless steel (SUS), and is molded into 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 made of a clad material having a three-layer structure including an outer surface layer made of nickel, a metal layer made of stainless steel (SUS), and a current collector layer made of copper, and is molded into a cup shape. . The negative electrode can 3 has a circular opening 3a formed in a folded shape, and a ring-shaped gasket 4 made of nylon, for example, is attached to the opening 3a.

Then, the negative electrode can 3 is fitted into the circular opening 2a of the positive electrode can 2 from the opening 3a side where the gasket 4 is mounted, and the opening 2a of the positive electrode can 2 is caulked toward the gasket 4 to seal it. By doing so, a disk-shaped (button-shaped or coin-shaped) case 8 is formed. A sealed space S is formed inside the case 8.
In this sealed space S, the positive electrode mixture 5, the separator 6, and the negative electrode mixture 7 are accommodated, and the positive electrode mixture 5 is disposed on the positive electrode can 2 side and the negative electrode mixture 7 is disposed on the negative electrode can 3 side with the separator 6 interposed therebetween. Has been.

  When assembling the flat alkaline primary battery 1, the positive electrode mixture 5 formed into a pellet is filled in the positive electrode can 2. And the gel-like negative mix 7 is mounted on the separator 6, and the negative electrode can 3 is covered on this. Furthermore, the case 8 is sealed by crimping the opening edge of the positive electrode can 2.

The positive electrode mixture 5 includes a positive electrode active material, a conductive agent, an electrolytic solution, a binder, and the like. The positive electrode active material is not particularly limited as long as it can be used as the positive electrode active material when zinc or a zinc alloy is used as the negative electrode active material. For example, the positive electrode active material may be silver oxide granules or manganese dioxide powder or a mixture thereof. Alternatively, the positive electrode active material may be nickel oxyhydroxide alone or nickel oxyhydroxide in which cobalt or the like is dissolved.
The negative electrode mixture 7 includes a negative electrode active material, a conductivity stabilizer, a gelling agent, an electrolytic solution, and a viscoelasticity adjusting material.

As the negative electrode active material, zinc powder or zinc alloy powder 11 is used. As the conductivity stabilizer, zinc oxide (ZnO) or the like can be used. The gelling agent is preferably carboxymethyl cellulose, polyacrylic acid, or a mixture of carboxymethyl cellulose and polyacrylic acid. By using carboxymethylcellulose or polyacrylic acid, the lyophilicity and liquid retention of the negative electrode mixture 7 with respect to the electrolytic solution can be improved.
As the electrolytic solution, an aqueous potassium hydroxide solution, an aqueous sodium hydroxide solution, or a mixture thereof can be used.

  The viscoelasticity adjusting material is blended in order to make the viscoelasticity of the negative electrode mixture 7 a viscoelasticity that provides good handling properties and to improve productivity. As this viscoelasticity adjusting material, a nonmetallic insulating powder 10 that does not react with a strongly alkaline electrolyte is used. Here, the state that does not chemically react with the electrolyte and does not absorb the electrolyte is defined as the state that does not react with the electrolyte.

  For example, when the required capacity of the battery is low and the ratio of the negative electrode active material is designed to be small, the ratio of the zinc powder or the zinc alloy powder 11 is small. Although the ratio increases, the volume ratio of the gelling agent containing the solid content (zinc powder or zinc alloy powder and insulating powder) and the electrolyte is well adjusted by adding the insulating powder 10. The viscoelasticity of the negative electrode mixture 7 can be adjusted to a favorable range.

  For example, when a predetermined amount of the negative electrode mixture 7 is placed on the separator, the negative electrode mixture 7 is filled while applying pressure to an assembly device in which a predetermined volume of the round hole is formed. Use a scraping tool or the like. Further, using the supply pin 13, the molded negative electrode mixture 7 is extracted from the round hole. In the case of the negative electrode mixture 7 containing the insulating powder, since the breakage of the negative electrode mixture 7 is improved, the negative electrode mixture 7 is easily peeled off from the inner peripheral surface of the round hole and the supply pin 13. Handling of the mixture 7 is facilitated and handling properties can be improved. Moreover, the dispersion | variation when the negative mix 7 is worn out a fixed amount, the mounting | distribution dispersion | variation at the time of mounting on a separator, and the dispersion | variation in weighing are suppressed, and productivity improves.

  The average particle diameter of the insulating powder 10 is preferably 60% to 140% of the average particle diameter of the zinc powder or the zinc alloy powder 11. The average particle diameter means a particle diameter (D50) corresponding to an integrated value of 50% in the particle size distribution curve. When the average particle diameter of the insulating powder 10 is less than 60% of the average particle diameter of the zinc powder or the zinc alloy powder 11, the effect as a viscoelasticity adjusting material cannot be obtained, and sufficient handling properties cannot be obtained. When the content exceeds 140%, the negative electrode active material, the conductivity stabilizer, the gelling agent, the electrolytic solution, and the viscoelasticity adjusting material are mixed to produce the negative electrode mixture 7. The zinc alloy powder is not uniformly dispersed, and the variation in the amount of the negative electrode active material contained in the scraped negative electrode mixture 7 becomes large, resulting in a large variation in electric capacity.

  FIG. 2 is a schematic diagram showing the effect on productivity when the average particle size of the insulating powder 10 is 110 μm or less. FIG. 2 (a) shows a negative electrode mixture containing an insulating powder 10 having an average particle size of 110 μm or more, a zinc powder or a zinc alloy powder 11, and a mixture 12 of a gelling agent and an electrolytic solution, which is formed into a cylindrical shape. It is a figure extruded from a round hole. When the supply pin 13 moves in the direction of the arrow and contacts the negative electrode mixture, the mixture 12 of the gelling agent and the electrolytic solution adhering around the insulating powder 10 and the zinc powder or the zinc alloy powder 11 is supplied to the supply pin 13. To touch.

  FIG. 2 (b) is a view showing a place where the supply pin 13 moves in the direction of the arrow and the negative electrode mixture is peeled off from the supply pin 13. In FIG. 2 (b), the negative electrode mixture is peeled off from the supply pin 13. Here, FIG. 2 is based on the results of verification using carboxymethyl cellulose as a gelling agent and an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution as an electrolytic solution.

  FIG. 2 (c) shows that a negative electrode mixture containing an insulating powder 10 having an average particle size of 110 μm or less, a zinc powder or a zinc alloy powder 11, and a mixture 12 of a gelling agent and an electrolytic solution is molded into a cylindrical shape. It is a figure extruded from a round hole. 2A, when the supply pin 13 moves in the direction of the arrow and contacts the negative electrode mixture, the gelling agent adhering around the insulating powder 10 and the zinc powder or the zinc alloy powder 11 The electrolyte mixture 12 contacts the supply pin 13.

FIG. 2 (d) is a diagram showing a place where the supply pin 13 moves in the direction of the arrow and the negative electrode mixture is peeled off from the supply pin 13.
Here, paying attention to the point where the negative electrode mixture, the negative electrode mixture, and the supply pin 13 are in contact with each other, in FIG. 2 (a), there are four contact points (circled points), and FIG. 2 (c). Then, there are 8 contact points, and it can be seen that there are more contact points in FIG. 2C than contact points in FIG. Moreover, the particle diameter of the insulating powder 10 is smaller in the cases of FIGS. 2C and 2D than in the cases of FIGS. 2A and 2B. For this reason, when the negative electrode mixture is peeled from the supply pin, if the average particle size of the insulating powder 10 is 110 μm or less, the insulating powder 10 adheres to the supply pin 13 as shown in FIG. Will remain. For this reason, if the negative electrode mixture is repeatedly extruded, the negative electrode mixture adhering to the supply pin 13 must be removed, and the productivity is lowered. If the average particle size of the insulating powder 10 is 110 μm or more, as shown in FIG. 2B, the negative electrode mixture is difficult to adhere to the supply pin 13, so it is not necessary to remove the negative electrode mixture from the supply pin. Even if it exists, the frequency is very less than the case where the average particle diameter of the insulating powder 10 is 110 micrometers or less. Moreover, it is preferable that the average particle diameter of this insulating powder is 350 micrometers or less.

The insulating powder preferably has water repellency. When the insulating powder having water repellency is used, the adhesive force between the electrolytic solution and the gelling agent and the insulating powder is further reduced, and the breakage when the negative electrode mixture 7 is weighed is improved.
Further, the insulating powder is any one of polytetrafluoroethylene, polypropylene, polyamide, polyethylene and acrylic resin from the viewpoints of water repellency, purity, price, ease of pulverization (processability), alkali resistance and the like. It is preferable to use one or a plurality of resin powders.

Furthermore, it is preferable that a compounding rate is 1 volume%-25 volume% with respect to the negative mix 7 as insulating powder. When the blending ratio is less than 1% by volume, the effect as a viscoelasticity adjusting material cannot be obtained, and sufficient handling properties cannot be obtained. Moreover, when it exceeds 25 volume%, the viscoelasticity of the negative mix 7 will become low too much, and the intensity | strength of the negative mix 7 will fall. When the strength of the negative electrode mixture 7 decreases, the shape of the negative electrode mixture 7 is collapsed when the negative electrode mixture 7 is placed on the separator, and a placement failure tends to occur.
Furthermore, the insulating powder is preferably spherical. When the spherical insulating powder is used, the frictional force with the gelling agent containing the electrolytic solution is reduced, and the breakage of the negative electrode mixture 7 is further improved.

Next, the example which changed the composition of the negative mix 7 was performed, and the effect of the said invention was verified.
Example 1
In this example, a SR626SW type (outer diameter 6.8 mm, height 2.6 mm, nominal capacity 30 mAh) flat alkaline primary battery having a nominal capacity reduced by 10% using a viscoelasticity adjusting material (Nominal capacity 27 mAh) was produced.

  The viscoelasticity adjusting material blended in the negative electrode mixture 7 was polyethylene powder, and the average particle size was 150 μm. Furthermore, the blending ratio of each composition constituting the negative electrode mixture 7 is as follows: zinc alloy powder 25.1% by volume, zinc oxide (ZnO) 1.3% by volume, carboxymethyl cellulose 4.9% by volume, and concentration 28% by mass. Sodium hydroxide aqueous solution 53.8 vol%, concentration 45 mass% potassium hydroxide aqueous solution 12.1 vol%, polyethylene 2.8 vol%. The average particle diameter of the zinc alloy powder was 150 μm, and the average particle diameter of the polyethylene powder with respect to the average particle diameter of the zinc alloy powder was 100%. These compositions were mixed to prepare a gelled negative electrode mixture 7.

The compounding ratio of each composition constituting the positive electrode mixture 5 was 92% by mass of silver oxide (Ag ₂ O), 5% by mass of manganese dioxide, 2% by mass of graphite, and 1% by mass of lanthanum nickel (LaNi ₅ ). The average particle size of silver oxide was 10 μm, the average particle size of manganese dioxide was 30 μm, the average particle size of graphite was 15 μm, and the average particle size of lanthanum nickel was 35 μm.

And these compositions were mixed and the positive mix 5 was produced by compression-molding to a pellet form. The positive electrode mixture 5 thus prepared was housed in an iron positive electrode can 2 plated with nickel, and a separator 6 was laid thereon. Further, a ring-shaped gasket 4 to be press-fitted into the positive electrode can 2 was inserted. Further, the negative electrode mixture 7 was placed on the separator, and the negative electrode can 3 was put on the negative electrode mixture 7 via the gasket 4. And the flat alkali primary battery 1 mentioned above was produced by caulking the opening edge part of the positive electrode can 2. As shown in FIG.
In addition, the separator 6 is comprised from a polyethylene film, a cellophane, and a nonwoven fabric, and the gasket 4 is a product made from polyamide.

(Example 2)
Unlike Example 1, the average particle diameter of the zinc alloy powder is 100 μm, the average particle diameter of the polyethylene powder is 110 μm, and the average particle diameter of the polyethylene powder with respect to the average particle diameter of the zinc alloy powder is 110%, Other configurations were the same as those in Example 1.
(Example 3)
The only difference from Example 1 is that the average particle size of the polyethylene powder is 110 μm, and the average particle size of the polyethylene powder is 73% with respect to the average particle size of the zinc alloy powder, and the other configurations are the same as in Example 1. I made it.
Example 4
The only difference from Example 1 is that the average particle diameter of the polyethylene powder is 210 μm, and the average particle diameter of the polyethylene powder is 140% with respect to the average particle diameter of the zinc alloy powder. I made it.
(Example 5)
Unlike Example 1, the average particle diameter of the zinc alloy powder is 250 μm, the average particle diameter of the polyethylene powder is 150 μm, and the average particle diameter of the polyethylene powder is 60% with respect to the average particle diameter of the zinc alloy powder. Other configurations were the same as those in Example 1.

(Example 6)
Unlike Example 1, the average particle size of the zinc alloy powder is 250 μm, the average particle size of the polyethylene powder is 350 μm, and the average particle size of the polyethylene powder with respect to the average particle size of the zinc alloy powder is 140%, Other configurations were the same as those in Example 1.
(Example 7)
The only difference from Example 1 was that the viscoelasticity adjusting material added to the negative electrode mixture 7 was polypropylene, and other configurations were the same as in Example 1.
(Example 8)
The only difference from Example 1 was that the viscoelasticity adjusting material added to the negative electrode mixture 7 was polyamide, and the rest of the configuration was the same as in Example 1.
Example 9
The difference from Example 1 was that polytetrafluoroethylene was used as the viscoelasticity adjusting material to be added to the negative electrode mixture 7, and the rest of the configuration was the same as Example 1.

(Example 10)
The only difference from Example 1 was that the viscoelasticity adjusting material added to the negative electrode mixture 7 was an acrylic resin, and other configurations were the same as in Example 1.
(Example 11)
The only difference from Example 1 was that the blending ratio of the polyethylene powder was 1.0% by volume, and the rest of the configuration was the same as Example 1.
(Example 12)
The only difference from Example 1 is that the blending ratio of the polyethylene powder is 25.0% by volume,
Other configurations were the same as those in Example 1.

(Comparative Example 1)
It differs from Example 1 only in that the viscoelasticity adjusting material is not added, and the other configurations are the same as in Example 1.
(Comparative Example 2)
Unlike Example 1, the average particle diameter of the zinc alloy powder is 100 μm, the average particle diameter of the polyethylene powder is 60 μm, and the average particle diameter of the resin powder with respect to the average particle diameter of the zinc alloy powder is 60%, Other configurations were the same as those in Example 1.
(Comparative Example 3)
The only difference from Example 1 is that the average particle diameter of the polyethylene powder is 30 μm, and the average particle diameter of the resin powder is 20% with respect to the average particle diameter of the zinc alloy powder. Other configurations are the same as in Example 1. did.
(Comparative Example 4)
The only difference from Example 1 was that the average particle diameter of the polyethylene powder was 270 μm, and the average particle diameter of the resin powder with respect to the average particle diameter of the zinc alloy powder was 180%. Other configurations were the same as in Example 1. .

(Comparative Example 5)
The only difference from Example 1 is that the average particle size of the zinc alloy powder is 250 μm, the average particle size of the polyethylene powder is 50 μm, and the average particle size of the resin powder with respect to the average particle size of the zinc alloy powder is 20%. Other configurations were the same as those in Example 1.
(Comparative Example 6)
Compared to Example 1, the only difference is that the average particle size of the zinc alloy powder is 250 μm, the average particle size of the polyethylene powder is 450 μm, and the average particle size of the resin powder with respect to the average particle size of the zinc alloy powder is 180%, Other configurations were the same as those in Example 1.
(Comparative Example 7)
The difference from Example 1 was that the blending ratio of the polyethylene powder was 0.5% by volume, and the rest of the configuration was the same as Example 1.
(Comparative Example 8)
The difference from Example 1 was that the blending ratio of the polyethylene powder was 27.0% by volume, and the other configuration was the same as that of Example 1.

<Verification>
And the flat alkaline primary battery 1 of Examples 1-12 and Comparative Examples 1-8 is produced, and the shape change at the time of mounting the negative mix 1 and mounting property, discharge capacity, and its variation coefficient are investigated. Therefore, the following verification was performed.

<Verification 1>
After filling the negative electrode mixture 7 by applying a predetermined pressure to a round hole of a predetermined volume, the negative electrode mixture 7 is rounded using a cylindrical pin that is slightly smaller than the round hole while scraping the top and bottom of the round hole. Extracted from the hole. And the shape change of the negative mix with respect to the round hole was investigated, and the presence or absence of the shape change of each Example and a comparative example was evaluated. The results are shown in the table of FIG. Here, the operation time (h) means an elapsed time from the operation of the apparatus, and in the table, the results from the start of operation to 1 hour and the results every hour thereafter are displayed up to 4 hours. “−” Indicates that the negative electrode mixture is completely broken and the cylindrical shape cannot be maintained.

<Verification 2>
The battery assembly machine was operated for 1 hour to produce flat alkaline primary batteries 1 of Examples 1 to 12 and Comparative Examples 1 to 8. Then, the number of defective flat alkaline primary batteries 1 due to the displacement of the negative electrode mixture 7 was investigated. The results are shown in the table of FIG. The operation time is the same as in the verification 1. “-” Indicates that the negative electrode mixture is broken and cannot be placed.

<Verification 3>
Of the flat alkaline primary batteries 1 produced under the conditions of Examples 1 to 12 and Comparative Examples 1 to 8, 5 were each discharged continuously with a load resistance of 30 kΩ, and discharge when 0.9 V was used as the end voltage. The capacity [mAh] was examined, the coefficient of variation (standard deviation / average value × 100) was calculated, and the capacity variation due to the weighing variation was examined. The results are shown in the table of FIG. The operation time is the same as in the verification 1. “−” In the coefficient of variation in discharge capacity indicates that the battery could not be produced because the negative electrode mixture collapsed and could not be placed.

<Examination of verification results>
When comparing Comparative Example 1 and Examples 1 to 12, in Comparative Example 1, the shape collapsed in 2 to 3 hours from the start of operation. Moreover, the mounting failure and the change in the discharge capacity occurred within one hour from the start of operation. That is, it can be seen that by adding the resin powder to the negative electrode mixture 7, variation in placement of the negative electrode mixture 7 can be reduced, so that productivity can be improved. This is because the viscoelasticity of the negative electrode mixture 7 can be brought into a preferable state by adding an appropriate amount of resin powder to the negative electrode mixture 7. In addition, it can be seen from the coefficient of variation of the discharge capacity obtained in the verification 3 that by adding resin powder to the negative electrode mixture 7, variation in electric capacity can be reduced. This is because adding the resin powder having water repellency to the negative electrode mixture 7 improves the breakage of the negative electrode mixture itself and reduces the weighing variation.

  ・ Comparison between Comparative Example 2 and Example 2 shows that mounting failure has occurred in Comparative Example 2 from the start of operation, whereas in Example 2, mounting failure occurred even after 4 hours of operation. Has not occurred. It can be seen that the variation coefficient of the discharge capacity is lower in Example 2. Further, the shape of Example 2 was good even in operation for 4 hours, whereas in Comparative Example 2, collapse occurred in 3 to 4 hours from the start of operation. These show that productivity can be improved by keeping the average particle size of the resin powder at 110 μm or more even when the particle size of the resin powder is within 60 to 140% with respect to the average particle size of the zinc alloy powder.

  ・ Comparison between Comparative Examples 3 and 4 and Examples 3 and 4 shows that the shapes of Examples 3 and 4 are good in operation for 4 hours, whereas in Comparative Example 3, collapse occurs in 2 to 3 hours. doing. In the number of placement failures, one case is 3 to 4 hours in Example 3, and no placement failure occurs even in operation for 4 hours in Example 4, whereas in Comparative Example 3, immediately after operation, a comparative example In No. 4, a mounting failure occurs in 2 to 3 hours. That is, it can be seen that by adjusting the resin powder particle size within a range satisfying that the average particle size of the resin powder is 110 μm or more, it is possible to suppress poor mounting and variation in weighing.

  ・ Comparison between Comparative Examples 5 and 6 and Examples 5 and 6 shows that the shapes of Examples 5 and 6 are good in operation for 4 hours, whereas in Comparative Example 5, collapse occurs in 2 to 3 hours. doing. In the number of placement failures, one case is 3 to 4 hours in Example 5, and no placement failure occurs even in operation for 4 hours in Example 6, whereas in Comparative Example 5, immediately after operation, a comparative example In No. 6, a placement failure occurs in 2 to 3 hours. That is, even when the average particle diameter of the zinc alloy powder is changed to 250 μm, the average particle diameter of the resin powder is adjusted by adjusting the particle diameter of the resin powder to 60 to 140% with respect to the average particle diameter of the zinc alloy powder. It can be seen that misplacement and variation in weighing can be suppressed.

Here, as the zinc powder or zinc alloy powder used for the negative electrode of a flat primary battery typified by a silver oxide battery, one having an average particle diameter of 50 to 250 μm is generally used. When this average particle size is less than 50 μm, the surface area of zinc increases, so there is a risk of spontaneous ignition in the air, and handling is difficult. On the other hand, when the thickness exceeds 250 μm, the surface area of zinc is reduced, so that the discharge characteristics when the battery is made deteriorate. Since the maximum value of the average particle diameter of the zinc powder or the zinc alloy powder is 250 μm from Example 6, the maximum value of the resin powder is 250 μm × 140% = 350 μm.

  When comparing Comparative Examples 7 and 8 with Examples 11 and 12, the shapes of both Examples 11 and 12 are good in operation for 4 hours, while Comparative Example 7 is 2 to 3 hours and Comparative Example 8 is Collapse occurs in 1 to 2 hours. In the number of placement failures, the placement failure occurred in Example 11 in 2 to 3 hours and in Example 12 in 3 to 4 hours, whereas in Comparative Example 7 immediately after the operation, in Comparative Example 8 it was 1 to 1. A mounting failure occurs in 2 hours. That is, it can be seen that when the blending ratio of the resin powder is less than 1% by volume, the viscoelasticity of the negative electrode mixture increases and does not serve as a viscoelasticity adjusting material. Moreover, when the compounding ratio of the resin powder exceeded 25% by volume, since the amount of the resin powder in the negative electrode mixture was too much, the shape could not be maintained even with a slight stress. Also in this case, it can be seen that it does not serve as a viscoelasticity adjusting material.

According to the embodiment, it can be seen that the following effects are obtained.
(1) According to the above embodiment, the negative electrode mixture 7 has zinc powder or zinc alloy powder as a main negative electrode active material, contains a gelling agent, and has a mean particle size of 110 μm or more as a viscoelasticity adjusting material. And non-metallic insulating powder that does not react with the electrolytic solution of 60% to 140% of the average particle diameter of zinc or zinc alloy powder. For this reason, even if the ratio of a gelatinizer becomes large, the viscoelasticity of the negative mix 7 can be adjusted by adding insulating powder. Therefore, it is possible to improve the handling property when weighing and molding the negative electrode mixture 7 while maintaining the required electric capacity of the battery. Moreover, the mounting variation and the weighing variation are suppressed, and the productivity can be improved.

(2) According to the above embodiment, the insulating powder blended in the negative electrode mixture 7 as a viscoelasticity adjusting material is composed of one or more of polytetrafluoroethylene, polypropylene, polyamide, polyethylene and acrylic resin. Resin powder was used. For this reason, the viscoelasticity of the negative electrode mixture 7 can be adjusted using powder satisfying conditions such as water repellency, price, workability, and alkali resistance.

(3) According to the said embodiment, the negative mix 7 contains 1 volume%-25 volume% of insulating powder. For this reason, good handling properties can be obtained while maintaining the electric capacity of the battery at the required capacity.
In addition, you may change the said embodiment as follows.
As the flat primary battery 1, as described above, an alkaline button battery using manganese dioxide as a positive electrode active material, a silver oxide battery using silver oxide, a battery using nickel oxyhydroxide, and an air zinc having an air electrode A battery may be used.

DESCRIPTION OF SYMBOLS 1 ... Flat alkaline primary battery 2 as a flat primary battery 2 ... Positive electrode can 3 ... Negative electrode can 4 ... Gasket 5 ... Positive electrode mixture 6 ... Separator 7 ... Negative electrode mixture 8 ... Case 10 ... Insulating powder 11 ... Zinc powder or Zinc alloy powder 12 ... Mixture of gelling agent and electrolyte 13 ... Supply pin

Claims (4)

A negative electrode mixture for a flat primary battery, comprising a negative electrode active material, a conductivity stabilizer, a gelling agent, an electrolytic solution, and a viscoelasticity adjusting material,
The negative electrode active material is zinc powder or zinc alloy powder having an average particle size of 50 μm or more and 250 μm,
The viscoelasticity adjusting material may be any one of polytetrafluoroethylene, polyamide, polyethylene, and acrylic resin having an average particle size of 110 μm to 350 μm and 60% to 140% of the average particle size of the negative electrode active material. Alternatively, a negative electrode mixture for flat primary batteries, which is a plurality of resin powders and is contained in the negative electrode mixture in an amount of 1% by volume to 25% by volume.   2. The negative electrode mixture for a flat primary battery according to claim 1, wherein the gelling agent includes carboxymethyl cellulose, polyacrylic acid, or a mixture thereof.   A flat primary battery using the negative electrode mixture according to claim 1. Filling a positive electrode can with a positive electrode mixture, laying a separator on the positive electrode mixture, and press-fitting a gasket;
A flat primary battery comprising: a step of placing the negative electrode mixture according to claim 1 on the separator, covering the negative electrode can, and crimping and sealing an opening edge of the positive electrode can. Method.

Images