JP2009087872A - Alkali battery, and method of manufacturing positive electrode mixture in alkali battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost alkali battery whose discharge characteristic is sufficiently secured. <P>SOLUTION: In the alkali battery, a positive electrode mixture containing a positive electrode active material, a conductive material and a binder is disposed in a battery can, and the positive electrode mixture contains an additive having an effect of promoting fluidity of a powder and an effect of preventing internal short circuit. A method of manufacturing the positive electrode mixture comprises an active substance mixing step of mixing a positive electrode active material and a conductive material, an addition step of adding the additive to a binder, a dry mixing step of dry-mixing the mixture obtained in the active substance mixing step and the binder having the additive added, a wet mixing step of adding an electrolyte to the mixture obtained in the dry-mixing step and kneading the resultant mixture, and a step of compression molding the mixed and kneaded material obtained in the wet-mixing step into an annular solid positive electrode mixture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an alkaline battery and a method for producing a positive electrode mixture in the alkaline battery. Specifically, the present invention relates to a technique for improving a positive electrode mixture for increasing the strength of the positive electrode mixture or preventing an internal short circuit when an alkaline battery is subjected to light load discharge and intermittent discharge. For example, it is particularly effective when applied to a cylindrical alkaline battery.

  For example, alkaline batteries such as LR6 have a positive electrode mixture mainly composed of manganese dioxide, a conductive agent composed of graphite, an alkaline electrolyte composed of a high concentration potassium hydroxide aqueous solution, and a negative electrode composition mainly composed of gelled zinc. It is produced using an agent. FIG. 3 shows the structure of a general alkaline battery. The alkaline power generation element 20 is disposed inside a positive electrode mixture 21, a so-called positive electrode core, and a positive electrode mixture 21 inserted into a circular solid inserted into a bottomed cylindrical metal battery can 11. The formed cylindrical separator 22 and a gelled negative electrode mixture 23 filled inside the separator are formed. The opening of the battery can 11 is sealed using a negative electrode terminal plate 32 and a sealing gasket 35, and a rod-shaped negative electrode current collector 31 is erected and fixed by spot welding or the like inside the battery of the negative electrode terminal plate 32. Yes. The negative electrode current collector 31 is inserted into the negative electrode mixture 23.

  In the structure of the dry battery 10 described above, the battery can 11 is in close contact with the positive electrode mixture 21 and also serves as the positive electrode current collector and the positive electrode terminal 12. Accordingly, the positive electrode mixture 21 needs to have a sufficient molding strength so that breakage such as cracking does not occur in the assembly process of the dry battery 10 or the like. As is well known, the positive electrode mixture is obtained by press-molding a mixture of a conductive material such as manganese dioxide and graphite as an active material and a binder with a mold or the like. FIG. 4 shows a general method for producing a positive electrode mixture. First, the positive electrode active material, the graphite serving as the conductive material, and the binder are weighed and mixed (dry mixing), and the electrolyte is added to the mixture and kneaded (wet mixing). Then, this kneaded product is rolled and crushed (granulated) by a compression process, and processed in a process such as sieving to select a granulated product of a predetermined particle size, and then this granulated product (granulated mixture) is cyclically formed. It is compression molded into a solid and formed into a positive electrode mixture. The binder secures the molding strength of the positive electrode mixture by binding the positive electrode active material in a powder that contributes to the discharge action and the conductive agent to each other. Examples of the binder include polyacrylic acid and a salt thereof (for example, sodium polyacrylate), polyethylene, and the like.

  The amount of binder added is appropriately increased or decreased depending on the type of binder. For example, since polyethylene has little thickening action, sufficient strength cannot be obtained unless the addition amount is increased. When polyethylene is used as the binder, even if the added amount of the measured amount is not mixed correctly and added in a reduced amount, the absolute added amount is large. There is little possibility that the binder will be present in the grains and the molding strength will be insufficient. However, since a large amount of binder that does not contribute to power generation is added, the capacity of the battery is naturally reduced.

  Polyacrylic acid or a salt thereof having a large thickening effect may be added in a minute amount, but it is difficult to reliably add a minute amount of a precisely measured amount of powder. For example, when polyacrylic acid is supplied to be added to a mixture of a positive electrode active material and a conductive agent, it remains in the supply path due to friction of the powder itself, and the measured polyacrylic acid is not accurately mixed. There is a case. In addition, since the thickening action is large, during the wet mixing, the viscosity increases before being uniformly dispersed in the mixture composed of the positive electrode active material and the conductive material, and the polyacrylic acid is unevenly distributed in the mixture. Therefore, when a mixture granule having a small amount of polyacrylic acid is granulated and compression molding is performed in a state where the mixture granule is mixed, insufficient molding strength is generated at a portion where the mixture granule is present. If the mixture has insufficient strength, the mixture is damaged when the dry battery is manufactured, such as the step of inserting the mixture into the battery can, and the manufacturing yield of the battery is reduced. Eventually, even polyacrylic acid, which may be added in a small amount, is added in an increased amount in order to prevent the mixture from being damaged in the subsequent battery manufacturing process, thereby reducing the capacity of the battery.

  In addition, conventional alkaline batteries have a light load discharge (memory backup, power supply for watches, etc.) or intermittent discharge (for example, 5 m / d: power supply for electric razors, electric toothbrushes, etc.) on the separator. There is a problem in that zinc oxide is deposited, and this zinc oxide penetrates through a separator that insulates the positive electrode and the negative electrode to cause an internal short circuit. That is, an alkaline battery that has undergone an internal short circuit is self-discharged, resulting in a problem that the discharge capacity is reduced and the discharge characteristics are deteriorated. In addition, due to the spread of heavy load discharge devices such as digital cameras in recent years, alkaline batteries are required to reduce internal resistance, and in order to reduce the internal resistance, the separator is often made thin. Therefore, it can be said that the present alkaline battery has a high possibility of causing an internal short circuit during light load discharge or intermittent discharge.

  The present inventors considered the precipitation of zinc oxide and thought that the uniform dispersion of the binder in the positive electrode mixture might lead to the precipitation of zinc oxide and the accompanying internal short circuit. . That is, if the binder is not uniformly dispersed in the positive electrode mixture, a binder lump is locally present, and the lump absorbs the electrolytic solution. Then, it was considered that the electrolyte solution was insufficient around the lump, and zinc oxide was likely to be precipitated when the electrolyte solution was insufficient.

  In addition, the relationship between the density of the positive electrode mixture formed into an annular solid and the internal short circuit was also considered. That is, when the density is low, there are many voids in the positive electrode mixture, and if a certain amount of electrolytic solution is injected into the battery can, the electrolytic solution is easily absorbed in the portion with many voids. And electrolyte solution runs short in other parts, and it becomes easy to precipitate zinc oxide in the shortage part.

  On the other hand, when the density is high, more electrolytic solution is consumed by the discharge, and the electrolytic solution is gradually deficient along with the discharge, so that zinc oxide is likely to be deposited. Therefore, making the density of the positive electrode mixture formed into an annular solid uniform can also be a requirement for preventing an internal short circuit.

  Furthermore, a method for suppressing the precipitation of zinc oxide, which causes an internal short circuit, was also examined. For example, in JP-A-8-7890, the conductivity of zinc oxide, which causes an internal short circuit, is suppressed by adjusting the amount of sodium in the gelled negative electrode. Specifically, a negative electrode active material such as zinc powder (such as zinc powder) is dispersed in a gel electrolyte composed of an alkaline electrolyte such as potassium hydroxide and a gelling agent mainly composed of sodium polyacrylate. By adjusting the amount of sodium in the gelled negative electrode, the conductivity of zinc oxide that causes an internal short circuit is suppressed. In Japanese Patent Application Laid-Open No. 09-35720, precipitation of zinc oxide is suppressed by adding silicon to the negative electrode mixture.

  Therefore, as described above, any material for uniformly dispersing the binder in the positive electrode mixture or making the density of the positive electrode mixture uniform has a function of further suppressing the precipitation of zinc oxide itself. For example, it was considered that the strength of the positive electrode mixture was increased to improve the production yield of the alkaline battery, and it was possible to provide an alkaline battery that has excellent discharge performance and is less likely to cause an internal short circuit.

  The present invention has been made in view of the above problems and based on the above considerations, and by improving the positive electrode mixture in the alkaline battery, it is possible to improve discharge capacity, prevent internal short circuit, improve yield in the manufacturing process, etc. An object of the present invention is to provide an alkaline battery that can be used. Specifically, a small amount of added binder is surely added as weighed, and is uniformly dispersed during wet mixing, or the positive electrode mixture is molded into a cyclic solid with a uniform density, resulting in sufficient molding strength. Is intended to provide a low-cost alkaline battery with sufficient discharge characteristics by using a positive electrode mixture that is less likely to cause internal short circuit by reducing zinc oxide precipitation. . Another object of the present invention is to provide a method for producing the positive electrode mixture.

  In order to achieve the above object, the present invention provides an alkaline battery in which a positive electrode mixture containing a positive electrode active material, a conductive material, and a binder is inserted into a battery can. Thus, an alkaline battery containing an additive having the effect of promoting the fluidity and the effect of preventing an internal short circuit was obtained. It is good also as an alkaline battery by which the said positive mix is press-fitted in a battery can.

  In the alkaline battery, it is more preferable that the additive contains silicon or silicon oxide, and that the additive is silicon dioxide. Further, if the binder is polyacrylic acid or a salt of polyacrylic acid, the effect of the additive becomes remarkable. The salt of polyacrylic acid can be sodium polyacrylate.

  More preferably, an alkaline battery in which 2 to 15% by weight of the additive is added to the binder is used. Or it is set as the alkaline battery by which the said additive is 0.01-0.05weight% with respect to the positive mix particle obtained by mixing and granulating a positive electrode active material, a electrically conductive material, and a binder. That is.

  The manufacturing method of the positive electrode mixture used in the alkaline battery is also within the scope of the present invention. The manufacturing method includes an active material mixing step of mixing the positive electrode active material and the conductive material, and the additive is added to the binder. An adding step, a dry mixing step of dry mixing the mixture by the active material mixing step and the binder to which the additive is added, a wet mixing step of adding an electrolyte to the mixture by the dry mixing step and kneading the mixture, And a step of compressing and molding the kneaded product obtained by the wet mixing step into an annular solid positive electrode mixture.

  The positive electrode mixture used in the alkaline battery according to the present invention is a positive electrode mixture (granulated mixture) before being molded into a circular solid in the production process, and an additive for promoting the fluidity of the binder The agent is included. Therefore, the positive electrode mixture formed into a predetermined volume of an annular solid has little variation in weight (the density becomes uniform). Alternatively, the weighed binder is accurately added to the positive electrode active material and uniformly dispersed in the mixture.

  Therefore, the positive electrode mixture formed into a solid shape in a ring has a sufficient molding strength, and the alkaline battery of the present invention using the positive electrode mixture has an improved yield at the time of manufacture and is low in cost. Manufacture is possible. Further, it is possible to suppress the precipitation of zinc oxide that causes an internal short circuit due to the shortage of the electrolyte. Moreover, the additive itself also has a function of suppressing internal short circuit, and the occurrence of internal short circuit can be reliably prevented.

  Therefore, the alkaline battery of the present invention can be expected to be provided at a low price by improving the production yield. Moreover, sufficient discharge performance can be ensured.

=== Production Method of Positive Electrode Mixture ===
1 and 2 show a method for producing a positive electrode mixture according to the present invention. In these drawings, the manufacturing process of the positive electrode mixture is shown. In the process shown in FIG. 1 (hereinafter, manufacturing method A), the measured positive electrode active material (manganese dioxide) and the conductive agent (graphite) are mixed. Then, a material (additive) for promoting the measured fluidity is added to the measured binder, and the binder to which the additive is added is dry-mixed together with the mixture composed of the positive electrode active material and the conductive agent. Electrolyte is added to this dry mixture and wet-mixed, and after rolling, sieving to make the granulated mixture a predetermined particle size, etc., the granulated product is compressed to form a solid annular positive electrode Mold into a mixture.

  In the step shown in FIG. 2 (hereinafter referred to as “Production Method B”), the weighed positive electrode active material, the conductive agent and the binder are dry-mixed together, and an electrolytic solution is added to this dry-type mixture and wet-mixed. This wet mixture becomes a granulated product (granulated mixture) through processing (compression) such as rolling, granulation, and sieving to obtain a predetermined particle size. Next, the weight ratio of the additive to the granulation mixture is measured, and the additive is added to the granulation mixture. Then, the granulated mixture to which the additive has been added is compressed and molded into a solid annular positive electrode mixture.

=== Sample ==
A positive electrode mixture was prepared by changing various conditions such as the above two production methods, additive types and addition amounts, and binder type, and the positive electrode mixture was used as a sample. And the dispersion | variation in weight, fracture strength, etc. were evaluated about the sample. Moreover, the produced positive electrode mixture was employ | adopted for the battery shown in FIG. 3, and the discharge performance of the sample was evaluated.

=== Example 1 ===
First, the effect of promoting the fluidity of the binder by the additive was examined. In the examination, a positive electrode mixture prepared by a conventional method and a positive electrode mixture prepared according to Manufacturing Method A were prepared as samples, and the fracture strength and light load discharge performance of these samples were evaluated.

Table 1 shows the evaluation results.

  The breaking strength is an index of the strength (molding strength) of the positive electrode mixture in a state of being molded into an annular solid, and is a pressure when the mixture is broken by performing a pressure test. Further, the sample was incorporated as the positive electrode mixture 21 of the LR6 alkaline battery 10 shown in FIG. 3, and the light load discharge characteristics of the alkaline battery were evaluated. The light load discharge performance was evaluated by the discharge time until a final voltage of 0.9 V was obtained by discharging for 4 hours per day with a load of 43Ω. In addition, evaluation about the breaking strength and light load discharge performance in each sample produced 100 pieces of the same conditions one by one, made the average value, and the superiority / inferiority between samples was shown by the relative value.

  Table 1 shows the evaluation results for improving the strength and maintaining the discharge characteristics by adding the additive. Sample 1 used polyethylene (PE) as a binder, and samples 2 to 4 used polyacrylic acid (PA). The polyethylene content is 2.0 wt% with respect to the total amount of the positive electrode material (positive electrode active material, conductive material, binder) during dry mixing, and polyacrylic acid is 0.3 wt%. Samples 3 and 4 are mainly added with an additive for the purpose of promoting the fluidity of the binder. Sample 3 contains 5 wt% of aluminum silicate as an additive in the binder, and Sample 4 contains 5 wt% of silicon dioxide as an additive in the binder.

  Evaluation was shown by the relative value which set the average value in Sample 2, ie, the positive electrode mixture produced using the polyacrylic acid which does not add an additive as 100, as 100. Moreover, about the fracture strength, the minimum value was also shown, and (average value−minimum value) / average value was evaluated as “difference” in the molding strength. In other words, in an actual production line, in order to improve the yield, it is necessary to add a binder amount assuming that the molding strength is the smallest. If the difference is large, an additional amount of binder is added to minimize the molding. This is because the strength must be ensured.

  In Table 1, in the case of polyethylene, which is considered to have good fluidity, the average value of the breaking strength is 75% of that of Sample 2 even when an amount about 7 times that of polyacrylic acid is added. Was 95% of Sample 2 due to the large amount of binder. In addition, since a sufficient amount of polyethylene was included in the positive electrode mixture, the variation in fracture strength was as small as 13%.

  On the other hand, in the case of polyacrylic acid that can provide a sufficient viscosity even in a small amount, in sample 2 where no additive is added, the amount of polyacrylic acid tends to be unstable, and it is difficult to uniformly disperse in the positive electrode mixture. As a result, the variation in fracture strength was 35%. On the other hand, for samples 3 and 4 produced based on the method of the present invention, the average breaking strength was 100, which was the same as that of sample 2, and the molding strength was secured. Furthermore, there was very little variation in fracture strength. Moreover, the discharge performance was also ensured.

=== Example 2 ===
Next, in order to obtain the optimum conditions for producing the positive electrode mixture by the above method A using polyacrylic acid as a binder, the breaking strength and the light load discharge performance with respect to the additive amount were examined. In the case of the examination, samples 5 to 9 in which polyacrylic acid was mixed in an amount of 0.3 wt% with respect to the total amount of the positive electrode mixture, and silicon dioxide was added in the range of 1 to 16 wt% as an additive to the polyacrylic acid. Produced. Similarly to Samples 1 to 4, 100 samples of these Samples 5 to 9 were prepared and evaluated by relative values with respect to the average value of Sample 2.

Table 2 shows the amount of additive added, the breaking strength, and the evaluation results of the discharge characteristics.

  Sample 5 with a small amount of additive (1 wt%) secured sufficient performance in terms of average value for both breaking strength and discharge performance, but there was some variation (20%) in breaking strength. For other samples, sufficient fracture strength was secured, and the variation was less than 10%. In Sample 9 where the additive was 16 wt%, the discharge performance slightly decreased (5%). Sample 7 in Table 2 is a positive electrode mixture produced under the same conditions as Sample 4 in Example 1. Hereinafter, in the table, for samples produced under the same conditions, the sample number is shown in parentheses. showed that.

=== Example 3 ===
In the said Example 1, 2, the effect by adding an additive to a binder and mainly promoting the fluidity | liquidity of a binder was examined. That is, with respect to the positive electrode mixture produced according to the production method A, the breaking strength and the light load discharge performance were evaluated. In the following examples, samples in which the production method and the production conditions thereof are variously changed are produced, and the effect of preventing internal short circuit by adding an additive is mainly examined.

  First, the variation in the weight of the positive electrode mixture produced according to the production method B and the positive electrode mixture were applied to an alkaline battery to evaluate intermittent discharge characteristics. Table 3 shows the results. Table 4 shows the results of evaluation of intermittent discharge characteristics for various samples in which silicon dioxide is used as the additive and the presence / absence of the additive and the type of binder are appropriately combined.

  In each sample shown in Tables 3 and 4, when the binder is polyethylene, the amount of the binder is 2.0 wt% with respect to the granulation mixture, and when the binder is polyacrylic acid, The amount was 0.3 wt% with respect to the granulation mixture. And about the sample to which the additive is added, 0.02 wt% additive is added with respect to the granulation mixture in any case.

Tables 3 and 4 are shown below.

  In Table 3, 100 samples were prepared and molded into an annular solid having the same volume. In Table 3, the average value of the weight of each sample after being formed into a circular solid is 3.50 g, but the sample 10 containing no additive has a variation (R: the heaviest solid and the lightest solid). Difference) was 0.5 g. On the other hand, it was found that Samples 11 and 12 to which the additive was added had little variation with R = 0.22 g and R = 0.23 g, respectively.

  Moreover, the intermittent discharge performance used as the parameter | index about the presence or absence of internal short circuit generation | occurrence | production was evaluated. In the evaluation method, the discharge was performed for 5 minutes per day under a load of 3.9Ω, and the discharge time until reaching the final voltage of 0.9V was evaluated. The evaluation result of each sample is shown as a relative value when the average discharge time in Sample 13 using polyethylene as a binder as a conventional example is 100. From Tables 3 and 4, samples 14 and 15 with polyacrylic acid or sodium polyacrylate (Na-PA) as a binder and no additive added can confirm the apparent deterioration in intermittent discharge performance. It was shown that an internal short circuit occurred. In particular, sodium polyacrylate has a remarkable deterioration in intermittent discharge performance due to an internal short circuit.

  On the other hand, in Sample 12 (16) in which the binder was polyacrylic acid and the additive was silicon dioxide, the evaluation value of intermittent discharge performance was 100 as in the conventional example, and the occurrence of an internal short circuit could be prevented. Further, in sample 11 in which the binder is polyacrylic acid and the additive is aluminum silicate, and sample 17 in which the binder is sodium polyacrylate and the additive is silicon dioxide, the evaluation values of the intermittent discharge performance are 95 and 90, respectively. It was shown that almost all internal short circuits were suppressed.

  From the above, when polyacrylic acid to which no additive is added or sodium polyacrylate, which is a salt thereof, is used as a binder, there is a high possibility that an internal short circuit will occur, and in particular, sodium polyacrylate has a higher tendency. I understood that. Moreover, it can be said that the additive containing silicon has an effect of preventing an internal short circuit, and in particular, silicon dioxide has a high effect of preventing the internal short circuit.

=== Example 4 ===
From the results of Example 3, when silicon dioxide and aluminum silicate were used as additives, silicon dioxide was slightly superior in preventing internal short circuit. Moreover, in the case of the manufacturing process B, the polyacrylic acid was slightly superior to the sodium polyacrylate in preventing the internal short circuit. Then, the prevention effect of the internal short circuit by the difference in a manufacturing process was evaluated about the case where a sodium polyacrylate is used as a binder.

Table 5 shows the evaluation results.

  Samples 18 and 19 are binder type (sodium polyacrylate), weight ratio of binder to granulation mixture, additive type (silicon dioxide), weight ratio of additive to granulation mixture (0.02 wt%). ) Are the same, only the manufacturing process is different. Sample 18 is A and sample 19 is B. From Table 5, even if the weight ratio of the additive to the granulation mixture was the same, a difference was observed in the intermittent discharge performance depending on the production process A.

=== Example 5 ===
From Example 4, when manufacturing a positive mix by the manufacturing process A, it has confirmed that an internal short circuit was prevented reliably by making a binder sodium polyacrylate and making an additive silicon dioxide. However, under these conditions, if the breaking strength of the positive electrode mixture is insufficient, it cannot be put into practical use.

Therefore, the breaking strength of the positive electrode mixture produced under the above conditions was evaluated, and the evaluation results are shown in Table 6.

  Table 6 shows the result of comparing sample 20 similar to sample 1 in Example 1, and samples 21 and 22 in which other conditions were the same as samples 2 and 3 except that the binder was sodium polyacrylate. It was. From the results, it was found that the sample 22 in which sodium polyacrylate was used as a binder and an additive was added to the binder by the manufacturing method A improved the fracture strength and also reduced the strength difference.

Next, evaluation was performed to determine the optimum conditions for producing a positive electrode mixture by the production method A using sodium polyacrylate as a binder, and the results are shown in Table 7.

  From Table 7, when the amount of the additive was small (1 wt%), the binder was not uniformly dispersed in the granulated mixture, and the difference in fracture strength was large. Further, when the addition amount was more than 15% (16 wt%) with respect to the binder, the discharge time was shortened in the intermittent discharge performance. This is not due to an internal short circuit, but is thought to be due to the presence of a large amount of non-conductive additive in the positive electrode mixture. From the evaluation results shown in Table 7, when the binder is sodium polyacrylate, the additive is preferably added in an amount of 2 to 15 wt% with respect to the binder.

  Sample 19 in Table 5 contains 0.3 wt% sodium polyacrylate and 0.02 wt% silicon dioxide based on the granulation mixture, and the amount of silicon dioxide is about 6.7 wt% is included, and is within the range of 2 to 15 wt% which is the optimum condition in Table 7.

=== Example 6 ===
Next, the optimum conditions for producing a positive electrode mixture by the production method B using polyacrylic acid as a binder and silicon dioxide as an additive were studied.

The examination results are shown in Table 8.

  From Table 8, when the amount of the additive is small (0.005 wt%) with respect to the granulated mixture, the fluidity of the granulated mixture is poor, and there are many variations in weight when it is made into a cyclic solid. Deterioration of intermittent discharge performance was also observed. Further, when the addition amount is more than 0.05% (0.06 wt%) with respect to the granulated mixture, the intermittent discharge performance is deteriorated due to a large amount of non-conductive additive being contained in the positive electrode mixture. Was recognized. From Table 8, when the binder is polyacrylic acid, the additive is preferably added in an amount of 0.01 to 0.05 wt% with respect to the binder.

=== About the production method and the amount of additive added ===
In each of the above examples, the amount of additive added is shown by the weight ratio with respect to the binder or the weight ratio with respect to the granulated mixture, regardless of the production method. In other words, regardless of the manufacturing method, if the weight ratio of the additive to the binder or granulation mixture is within the proper range, the weight uniformity after molding into an annular solid, breaking strength, light load discharge performance, intermittent load discharge In terms of performance, it is possible to produce a positive electrode mixture that is extremely excellent. An alkaline battery using the positive electrode mixture can be expected to have an effect that the production yield is improved and provided at a low cost, a sufficient discharge capacity is ensured, and an internal short circuit hardly occurs.

  Even if the amount of the binder added is not increased, it is possible to provide an alkaline battery positive electrode mixture in which stable and sufficient molding strength is ensured. In addition, by using the positive electrode mixture, it is possible to improve the production yield and to provide an alkaline battery with ensured discharge performance at a low price. It is also possible to provide an alkaline battery that prevents internal short circuit and has excellent intermittent discharge characteristics.

It is process drawing which shows the manufacturing method A of the positive mix in the Example of this invention. It is process drawing which shows the manufacturing method B of the positive mix in the Example of this invention. It is sectional drawing of the alkaline battery with which the technique of this invention is applied. It is process drawing which shows the manufacturing method of the conventional positive mix.

Explanation of symbols

10 Alkaline battery 11 Battery can (positive electrode can)
DESCRIPTION OF SYMBOLS 12 Positive electrode terminal part 20 Electric power generation element 21 Positive electrode mixture 22 Separator 23 Negative electrode gel 31 Negative electrode current collector 32 Negative electrode terminal board 35 Gasket

Claims (10)

  An alkaline battery in which a positive electrode mixture containing a positive electrode active material, a conductive material, and a binder is inserted into a battery can, and the positive electrode mixture has an effect of promoting powder fluidity and an internal short circuit. An alkaline battery comprising an additive having an effect of preventing water.   An alkaline battery in which a positive electrode mixture containing a positive electrode active material, a conductive material, and a binder is press-fitted into a battery can, and the positive electrode mixture has an effect of promoting the fluidity of the binder and an internal short circuit. An alkaline battery comprising an additive having an effect of preventing. The alkaline battery according to claim 1, wherein the additive contains silicon.   The alkaline battery according to claim 1, wherein the additive contains silicon oxide.   The alkaline battery according to claim 4, wherein the additive is silicon dioxide.   The alkaline battery according to claim 1, wherein the binder is polyacrylic acid or a salt of polyacrylic acid.   The alkaline battery according to claim 1, wherein the binder is sodium polyacrylate.   The alkaline battery according to any one of claims 1 to 7, wherein the additive is added in an amount of 2 to 15% by weight with respect to the binder.   The additive is added in an amount of 0.01 to 0.05% by weight based on a positive electrode mixture particle obtained by mixing and granulating a positive electrode active material, a conductive material, and a binder. Item 8. The alkaline battery according to any one of Items 1 to 7. It is a manufacturing method of the said positive mix used for the alkaline battery in any one of Claims 1-9,
An active material mixing step of mixing the positive electrode active material and the conductive material;
An addition step of adding the additive to the binder;
A dry mixing step of dry mixing the mixture from the active material mixing step and the binder to which the additive is added;
A wet mixing step of adding an electrolytic solution to the mixture by the dry mixing step and kneading; and
A method for producing a positive electrode mixture in an alkaline battery, comprising: a step of compressing and molding the kneaded product obtained by the wet mixing step into a positive electrode mixture of a cyclic solid.

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