Battery manufacturing method

Abstract

To improve one of the discharge performance for medium and light loads and the discharge performance for heavy loads without deteriorating the other.SOLUTION: The battery manufacturing method includes the step of granulating a first granulated compound using first electrolytic manganese dioxide and first graphite (steps S1 to S9), granulating a second granulated compound using second electrolytic manganese dioxide different from the first electrolytic manganese dioxide and second graphite different from the first graphite (steps S11 to S19), generating a mixture by mixing the first granulated compound with the second granulated compound (step S20), and molding the mixture into a positive electrode.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a battery manufacturing method and a battery. [Background technology]

[0002] Alkaline batteries are known in which the positive and negative electrodes are immersed in an electrolyte. The positive electrode is produced by molding a positive electrode mixture containing manganese dioxide (MnO2) and graphite (C) using a molding die. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-26979 [Patent Document 2] Japanese Patent Application Publication No. 01-281672 Summary of the Invention [Problem to be solved by the invention]

[0004] The discharge performance of alkaline batteries can be improved by using specific manganese dioxide or specific graphite in the positive electrode (Patent Documents 1 and 2). However, when specific manganese dioxide and graphite are used in alkaline batteries, improving discharge performance under medium to light loads can degrade discharge performance under heavy loads, and improving discharge performance under heavy loads can degrade discharge performance under medium to light loads.

[0005] The disclosed technology has been developed in consideration of these points, and aims to provide a battery manufacturing method and a battery that improves discharge performance under medium to light loads and discharge performance under heavy loads without deteriorating either one. [Means for solving the problem]

[0006] A battery manufacturing method according to one embodiment of the present disclosure includes granulating a first granulated mixture using first electrolytic manganese dioxide and first graphite. , th 2. Electrolytic manganese dioxide and 2. Granulating a second granulated mixture using graphite; and molding the mixture produced by mixing the first granulated mixture and the second granulated mixture into a positive electrode. The specific surface area of the second electrolytic manganese dioxide is larger than the specific surface area of the first electrolytic manganese dioxide, and the apparent density of the second graphite is larger than the apparent density of the first graphite. . [Effects of the Invention]

[0007] The disclosed battery manufacturing method and battery can improve discharge performance under medium to light loads and discharge performance under heavy loads without deteriorating the other. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a battery according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing the preparation of a positive electrode mixture in the battery manufacturing method of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a battery manufacturing method and a battery according to embodiments disclosed herein will be described with reference to the drawings. Note that the following description does not limit the technology of the present disclosure. In addition, in the following description, the same components are given the same reference numerals, and duplicated descriptions will be omitted.

[0010] [Battery 1 of the embodiment] The battery 1 of this embodiment is a so-called alkaline battery, and as shown in FIG. 1, includes a battery case 2, a positive electrode 3, a negative electrode 5, a current collector 6, and a separator 7. FIG. 1 is a cross-sectional view showing the battery 1 of this embodiment. The battery case 2 includes a positive electrode can 11, a negative electrode terminal plate 12, and a sealing gasket 14. The positive electrode can 11 is formed from a conductor, such as a metal. The positive electrode can 11 is formed in a cylindrical shape with a bottom, and includes a side portion 15 and a bottom portion 16. The side portion 15 is formed from a bent plate so as to fit along the side surface of the cylinder. The bottom portion 16 is disposed along one bottom surface of the cylinder. The bottom portion 16 is integrally connected to the side portion 15 so that an edge of the bottom portion 16 is adjacent to one end of the bottom portion 16.

[0011] A positive electrode terminal portion 17 is formed in the center of the bottom portion 16. The positive electrode terminal portion 17 is formed so as to protrude from the inside of the positive electrode can 11 toward the outside. An opening 18 is formed in the positive electrode can 11. The opening 18 is formed in a portion of the side portion 15 that corresponds to the other bottom surface of the cylinder. A beading portion 21 is formed in the side portion 15. The beading portion 21 is formed in the side portion 15 near the opening 18. The beading portion 21 is formed so that the inner diameter of a portion of the side portion 15 near the opening 18 is smaller.

[0012] The negative electrode terminal plate 12 is made of a conductor such as a metal and is formed in a generally disk shape. The negative electrode terminal plate 12 is arranged along the other bottom surface of the cylinder so as to close the opening 18 of the positive electrode can 11. Inside the battery case 2, the negative electrode terminal plate 12 closes the opening 18, thereby forming an internal space 23 surrounded by the positive electrode can 11 and the negative electrode terminal plate 12.

[0013] The sealing gasket 14 is formed from an insulator such as resin and is generally ring-shaped. The sealing gasket 14 surrounds the edge of the negative electrode terminal plate 12 and is disposed in the opening 18 of the positive electrode can 11. The sealing gasket 14 is sandwiched between the edge of the negative electrode terminal plate 12 and the positive electrode can 11, sealing the gap formed between the edge of the negative electrode terminal plate 12 and the positive electrode can 11. The negative electrode terminal plate 12 is fixed to the positive electrode can 11 via the sealing gasket 14 by being sandwiched between the edge of the negative electrode terminal plate 12 and the positive electrode can 11. The negative electrode terminal plate 12 is electrically insulated from the positive electrode can 11 via the sealing gasket 14 by being sandwiched between the edge of the negative electrode terminal plate 12 and the positive electrode can 11.

[0014] The positive electrode 3 is formed from a positive electrode active material, a binder, and an aqueous potassium hydroxide solution, and is shaped like a hollow cylinder. The positive electrode active material includes manganese dioxide (MnO2) and graphite (C). The binder contains, for example, a polymer compound, which bonds powders together to form a solid. The positive electrode 3 is disposed in the internal space 23 of the battery case 2 and is in close contact with the inner circumferential surface of the side portion 15 of the positive electrode can 11 so that the positive electrode active material is electrically connected to the positive electrode can 11. The negative electrode 5 is formed from a negative electrode active material and is in a gel state. The negative electrode active material includes zinc alloy powder and an aqueous potassium hydroxide solution. The negative electrode 5 is disposed inside the positive electrode 3 in the internal space 23 of the battery case 2.

[0015] The current collecting rod 6 is made of a conductor and has a rod-like shape. The current collecting rod 6 is disposed in the internal space 23 along the central axis of the cylinder along which the side portion 15 is disposed. The current collecting rod 6 is embedded in the negative electrode 5 so as to be electrically connected to the negative electrode active material of the negative electrode 5. The current collecting rod 6 also penetrates the center of the sealing gasket 14. One end of the current collecting rod 6 is joined to the negative electrode terminal plate 12 so as to be electrically connected to the negative electrode terminal plate 12.

[0016] The separator 7 is made of vinylon, pulp, or the like. The separator 7 is formed in the shape of a hollow cylinder with a bottom, and includes a side portion 25 and a bottom portion 26. The side portion 25 is disposed between the positive electrode 3 and the negative electrode 5 in the internal space 23. The bottom portion 26 is disposed between the negative electrode 5 and the bottom portion 16 of the positive electrode can 11 in the internal space 23. The bottom portion 26 is integrally connected to the side portion 25 so that the region of the internal space 23 where the negative electrode 5 is disposed is separated from the region of the internal space 23 where the positive electrode 3 and the positive electrode can 11 are disposed. By being disposed in this manner, the separator 7 separates the positive electrode 3 and the negative electrode 5, and separates the negative electrode 5 and the positive electrode can 11. The negative electrode 5 is electrically insulated from the positive electrode 3 via the separator 7 because the separator 7 separates the positive electrode 3 and the negative electrode 5, and is electrically insulated from the positive electrode can 11 via the separator 7 because the separator 7 separates the negative electrode 5 and the positive electrode can 11. The battery 1 further includes an electrolyte. The electrolyte is formed from an aqueous solution containing potassium hydroxide (KOH). The electrolyte is disposed in the internal space 23 so that the positive electrode 3 and the negative electrode 5 are immersed in the electrolyte, and the electrolyte permeates the separator 7 and the positive electrode 3.

[0017] [Battery manufacturing method according to an embodiment] The battery manufacturing method of the embodiment is a method for manufacturing a battery 1, and includes the steps of preparing a positive electrode mixture, molding a positive electrode, and assembling a battery. FIG. 2 is a flowchart showing the preparation of a positive electrode mixture in the battery manufacturing method of the embodiment. In preparing the positive electrode mixture, two types of electrolytic manganese dioxide (EMD), two types of graphite (Gr), a binder, and an electrolyte are prepared. The two types of electrolytic manganese dioxide are formed from a first electrolytic manganese dioxide and a second electrolytic manganese dioxide. The first electrolytic manganese dioxide and the second electrolytic manganese dioxide are each formed from a powder. 1The specific surface area of the electrolytic manganese dioxide is smaller than that of the second electrolytic manganese dioxide. The specific surface area is, for example, the BET specific surface area determined by the BET method using the Brunauer, Emmet and Teller equation (BET equation), and is measured using an automatic specific surface area measuring device, Gemini VII2390a, manufactured by Micromeritics. 1 The average particle size of electrolytic manganese dioxide is 2 The average particle size is smaller than that of electrolytic manganese dioxide. The average particle size is measured, for example, by using an HRA X-100 manufactured by Microtrac.

[0018] The two types of graphite are formed from a first graphite and a second graphite. The first graphite and the second graphite are each formed from powder. The apparent density of the second graphite is greater than the apparent density of the first graphite. The apparent density is measured, for example, by a method conforming to the method specified in JIS (Japanese Industrial Standards) JIS-Z-2504.

[0019] A predetermined amount of first electrolytic manganese dioxide is measured from the first electrolytic manganese dioxide (Step S1). A predetermined amount of first graphite is measured from the first graphite (Step S2). A predetermined amount of binder is measured from the binder (Step S3). The measured first electrolytic manganese dioxide, first graphite, and binder are dry-mixed (Step S4), and a dry mixture is produced by the dry mixing.

[0020] A predetermined amount of electrolyte is measured from the electrolyte (step S5). The measured electrolyte is added to the dry mixture and wet-mixed (step S6), producing a wet mixture by the wet mixing. The wet mixture is rolled using a roll press or the like (step S7), producing a sheet-like solid by the rolling. The solid is granulated by being crushed (step S8), producing a granular first granulated mixture by the granulation. The first granulated mixture is sieved (step S9), producing a first sieved granulated mixture by the sieving. The first sieved granulated mixture is formed from powder that does not pass through a predetermined fine sieve but passes through a predetermined coarse sieve.

[0021] A predetermined amount of second electrolytic manganese dioxide is measured from the second electrolytic manganese dioxide (step S11). A predetermined amount of second graphite is measured from the second graphite (step S12). A predetermined amount of binder is measured from the binder (step S13). The measured second electrolytic manganese dioxide, second graphite, and binder are dry-mixed (step S14), and a dry mixture is produced by the dry mixing.

[0022] A predetermined amount of electrolyte is measured from the electrolyte (step S15). The measured electrolyte is added to the dry mixture and wet-mixed (step S16), producing a wet mixture by the wet mixing. The wet mixture is rolled using a roll press or the like (step S17), producing a sheet-like solid by the rolling. The solid is granulated by being crushed (step S18), producing a granular second granulated mixture by the granulation. The second granulated mixture is sieved (step S19), producing a second sieved granulated mixture by the sieving. The second sieved granulated mixture is formed from powder that does not pass through a predetermined fine sieve but passes through a predetermined coarse sieve.

[0023] A predetermined amount of the first sieved granulated mixture is measured from the first sieved granulated mixture, and a predetermined amount of the second sieved granulated mixture is measured from the second sieved granulated mixture. The measured first sieved granulated mixture and the second sieved granulated mixture are mixed (step S20), and a positive electrode mixture is produced by this mixing. In the molding of the positive electrode, the positive electrode mixture produced by preparing the positive electrode mixture is molded to produce the positive electrode 3. In the molding process, the positive electrode mixture is poured into a molding die, a predetermined molding pressure is applied to the positive electrode mixture, and the produced positive electrode 3 is then removed from the molding die.

[0024] In assembling a battery, a positive electrode can 11 is prepared before the beading portion 21 is formed, and a separator 7 is also prepared. The positive electrode 3 is inserted into the positive electrode can 11 so that the outer peripheral surface of the positive electrode 3 contacts the inner peripheral surface of the positive electrode can 11. After the positive electrode 3 is inserted into the positive electrode can 11, the positive electrode can 11 is processed so that a beading portion 21 is formed at the opening 18 of the positive electrode can 11. The formation of the beading portion 21 on the positive electrode can 11 prevents the positive electrode 3 from slipping out of the positive electrode can 11. After the beading portion 21 is formed on the positive electrode can 11, a separator 7 is inserted inside the positive electrode 3. After the separator 7 is inserted inside the positive electrode 3, an electrolyte is injected inside the positive electrode 3 and allowed to soak into the separator 7. At this time, the electrolyte also soaks into the positive electrode 3.

[0025] In the battery assembly process, a gelled negative electrode 5 is prepared using zinc alloy powder and an aqueous potassium hydroxide solution, and a current collector 6, a negative electrode terminal plate 12, and a sealing gasket 14 are also prepared. The negative electrode 5 is then poured into the separator 7 after the separator 7 and the positive electrode 3 have been saturated with the electrolyte. After the negative electrode 5 is poured, the current collector 6, the negative electrode terminal plate 12, and the sealing gasket 14 are attached to the positive electrode can 11 so that the current collector 6 joined to the negative electrode terminal plate 12 is embedded in the negative electrode 5 and so that the negative electrode terminal plate 12 and the sealing gasket 14 close the opening 18. After the current collector 6, the negative electrode terminal plate 12, and the sealing gasket 14 are attached to the positive electrode can 11, the portion of the positive electrode can 11 near the opening 18 is crimped so that the gap formed between the edge of the negative electrode terminal plate 12 and the positive electrode can 11 is sealed with the sealing gasket 14. When the positive electrode can 11 is crimped, the sealing gasket 14 is deformed, the current collector rod 6, the negative electrode terminal plate 12, and the sealing gasket 14 are fixed to the positive electrode can 11, the internal space 23 is sealed from the outside, and the battery 1 is produced.

[0026] [Battery 1 evaluation test] In order to confirm the effects of the battery 1 of the embodiment, multiple battery samples were fabricated and multiple evaluation tests were performed on each of the multiple battery samples. Table 1 shows multiple fabrication conditions and multiple evaluation results corresponding to the multiple battery samples. [Table 1]

[0027] The plurality of battery samples include a battery of Comparative Example 1, a battery of Comparative Example 2, a battery of Comparative Example 3, a battery of Example 1, a battery of Example 2, a battery of Example 3, a battery of Example 4, a battery of Example 5, a battery of Example 6, a battery of Example 7, and a battery of Example 8. Each of the plurality of battery samples includes a plurality of batteries fabricated based on the battery manufacturing method described above.

[0028] The multiple battery samples were produced under different production conditions. The production conditions are represented by a first specific surface area, a first average particle size, a first apparent density, a second specific surface area, a second average particle size, and a second apparent density. The first specific surface area corresponding to a certain battery sample indicates the specific surface area of the first electrolytic manganese dioxide used in preparing the first granulated mixture for that battery sample. The first average particle size corresponding to a certain battery sample indicates the average particle size of the first electrolytic manganese dioxide used in preparing the first granulated mixture for that battery sample. The first apparent density corresponding to a certain battery sample indicates the apparent density of the first graphite used in preparing the first granulated mixture for that battery sample. The second specific surface area corresponding to a certain battery sample indicates the specific surface area of the second electrolytic manganese dioxide used in preparing the second granulated mixture for that battery sample. The second average particle size corresponding to a certain battery sample indicates the average particle size of the second electrolytic manganese dioxide used in preparing the second granulated mixture for that battery sample. The second apparent density corresponding to a certain battery sample indicates the apparent density of the second graphite used in preparing the second granulated mixture of that battery sample.

[0029] The multiple battery samples were fabricated identically except for the different fabrication conditions. That is, the multiple battery samples were fabricated such that the blending specifications of the first granulated mixture, the second granulated mixture, and the positive electrode mixture were all identical in the fabrication of the positive electrode mixture. The blending specifications of the first granulated mixture indicate the ratio of the amounts of the first electrolytic manganese dioxide, the first graphite, the binder, and the electrolyte formed in the first granulated mixture. The blending specifications of the second granulated mixture indicate the ratio of the amounts of the second electrolytic manganese dioxide, the second graphite, the binder, and the electrolyte formed in the second granulated mixture. The blending specifications of the positive electrode mixture indicate the ratio of the amounts of the first granulated mixture and the second granulated mixture formed in the positive electrode mixture.

[0030] For each of the battery samples, the positive electrode 3 is molded to have an LR6 battery size and to have the same molding pressure and positive electrode height. That is, in the molding of the positive electrode 3, an amount of positive electrode material mixture calculated backward so that the height of the molded positive electrode 3 is equal to the height of the positive electrode is poured into a molding die. A predetermined molding pressure is applied to the positive electrode material mixture, and then the manufactured positive electrode 3 is removed from the molding die. For each of the battery samples, a current collector 6, a separator 7, a positive electrode can 11, a negative electrode terminal plate 12, and a sealing gasket 14 are prepared for the battery assembly to have an LR6 battery size. In the battery assembly, an electrolyte is poured in an amount sufficient to allow the electrolyte to be absorbed by the separator 7 and the positive electrode 3.

[0031] The positive electrode 3 of the battery of Comparative Example 1 was made from one type of granulated mixture prepared using one type of electrolytic manganese dioxide and one type of graphite. Therefore, the first specific surface area of the electrolytic manganese dioxide of Comparative Example 1 indicates the specific surface area of that one type of electrolytic manganese dioxide, and is 35 m 2 / g. The first average particle size of the electrolytic manganese dioxide of Comparative Example 1 indicates the average particle size of that one type of electrolytic manganese dioxide, and is 40 μm. The first apparent density of the graphite of Comparative Example 1 indicates the apparent density of that one type of graphite, and is 0.08 g / cm 3 In other words, the second granulated mixture of the battery of Comparative Example 1 is formed in the same manner as the first granulated mixture of the battery of Comparative Example 1. In this case, the second specific surface area, second average particle size, and second apparent density of the battery of Comparative Example 1 are equal to the first specific surface area, first average particle size, and first apparent density of the battery of Comparative Example 1, respectively.

[0032] The positive electrode 3 of the battery of Comparative Example 2 was made from one type of granulated mixture prepared using one type of electrolytic manganese dioxide and one type of graphite. Therefore, the first specific surface area of the electrolytic manganese dioxide of Comparative Example 2 indicates the specific surface area of that one type of electrolytic manganese dioxide, and is 27 m 2 / g. The first average particle size of the electrolytic manganese dioxide of Comparative Example 2 indicates the average particle size of that one type of electrolytic manganese dioxide, and is 40 μm. The first apparent density of the graphite of Comparative Example 2 indicates the apparent density of that one type of graphite, and is 0.08 g / cm 3 In other words, the second granulated mixture of the battery of Comparative Example 2 is formed in the same manner as the first granulated mixture of the battery of Comparative Example 2. In this case, the second specific surface area, second average particle size, and second apparent density of the second electrolytic manganese dioxide of Comparative Example 2 are equal to the first specific surface area, first average particle size, and first apparent density of the battery of Comparative Example 2, respectively.

[0033] The positive electrode 3 of the battery of Comparative Example 3 was made from one type of granulated mixture prepared using one type of electrolytic manganese dioxide and one type of graphite. Therefore, the first specific surface area of the electrolytic manganese dioxide of Comparative Example 3 indicates the specific surface area of that one type of electrolytic manganese dioxide, and is 27 m 2 / g. The first average particle size of the electrolytic manganese dioxide of Comparative Example 3 indicates the average particle size of that one type of electrolytic manganese dioxide, and is 40 μm. The first apparent density of the graphite of Comparative Example 3 indicates the apparent density of that one type of graphite, and is 0.02 g / cm 3 In other words, the second granulated mixture of the battery of Comparative Example 3 is formed in the same manner as the first granulated mixture of the battery of Comparative Example 3. In this case, the second specific surface area, second average particle size, and second apparent density of the battery of Comparative Example 3 are equal to the first specific surface area, first average particle size, and first apparent density of the battery of Comparative Example 3, respectively.

[0034] The first specific surface area of the battery of Example 1 is 23 m 2 / g. The first average particle size of the battery of Example 1 is 40 μm. The first apparent density of the battery of Example 1 is 0.005 g / cm 3 The second specific surface area of the battery of Example 1 is 30 m 2 / g. The second average particle size of the battery of Example 1 is 40 μm. The second apparent density of the battery of Example 1 is 0.05 g / cm 3 This shows:

[0035] The first specific surface area of the battery of Example 2 is 25 m 2 / g. The first average particle size of the battery of Example 2 is 40 μm. The first apparent density of the battery of Example 2 is 0.01 g / cm 3 The second specific surface area of the battery of Example 2 is 33 m 2 / g. The second average particle size of the battery of Example 2 is 40 μm. The second apparent density of the battery of Example 2 is 0.06 g / cm 3 This shows:

[0036] The first specific surface area of the battery of Example 3 is 30 m 2 / g. The first average particle size of the battery of Example 3 is 40 μm. The first apparent density of the battery of Example 3 is 0.05 g / cm 3 The second specific surface area of the battery of Example 3 is 38 m 2 / g. The second average particle size of the battery of Example 3 is 40 μm. The second apparent density of the battery of Example 3 is 0.15 g / cm 3 This shows:

[0037] The first specific surface area of the battery of Example 4 is 33 m 2 / g. The first average particle size of the battery of Example 4 is 40 μm. The first apparent density of the battery of Example 4 is 0.06 g / cm 3 The second specific surface area of the battery of Example 4 is 40 m 2 / g. The second average particle size of the battery of Example 4 is 40 μm. The second apparent density of the battery of Example 4 is 0.2 g / cm 3 This shows:

[0038] The first specific surface area of the battery of Example 5 is 35 m 2 / g. The first average particle size of the battery of Example 5 is 33 μm. The first apparent density of the battery of Example 5 is 0.005 g / cm 3 The second specific surface area of the battery of Example 5 is 35 m 2 / g. The second average particle size of the battery of Example 5 is 45 μm. The second apparent density of the battery of Example 5 is 0.05 g / cm3 This shows:

[0039] The first specific surface area of the battery of Example 6 is 35 m 2 / g. The first average particle size of the battery of Example 6 is 35 μm. The first apparent density of the battery of Example 6 is 0.01 g / cm 3 The second specific surface area of the battery of Example 6 is 35 m 2 / g. The second average particle size of the battery of Example 6 is 46 μm. The second apparent density of the battery of Example 6 is 0.06 g / cm 3 This shows:

[0040] The first specific surface area of the battery of Example 7 is 35 m 2 / g. The first average particle size of the battery of Example 7 is 45 μm. The first apparent density of the battery of Example 7 is 0.05 g / cm 3 The second specific surface area of the battery of Example 7 is 35 m 2 / g. The second average particle size of the battery of Example 7 is 55 μm. The second apparent density of the battery of Example 7 is 0.15 g / cm 3 This shows:

[0041] The first specific surface area of the battery of Example 8 is 35 m 2 / g. The first average particle size of the battery of Example 8 is 46 μm. The first apparent density of the battery of Example 8 is 0.06 g / cm 3 The second specific surface area of the battery of Example 8 is 35 m 2 / g. The second average particle size of the battery of Example 8 is 58 μm. The second apparent density of the battery of Example 8 is 0.2 g / cm 3 This shows:

[0042] The multiple evaluation results include multiple filling weight evaluation results, multiple first discharge test results, and multiple second discharge test results. The multiple filling weights correspond to multiple battery samples. The filling weight corresponding to a certain battery sample among the multiple filling weights indicates the weight of the positive electrode 3 of that battery sample, and is the value obtained by dividing the weight of the positive electrode 3 of that battery sample by the weight of the positive electrode 3 of the battery of Comparative Example 1 and multiplying the result by 100. Among the multiple filling weights, a battery sample with a larger filling weight value indicates a larger amount of manganese dioxide and graphite contained in the positive electrode 3, and a battery sample with a larger filling weight value indicates a better filling property of the positive electrode 3. In battery 1, a battery sample with a better filling property of the positive electrode 3 has a smaller amount of electrolyte permeating into the positive electrode 3, resulting in poor electrolyte absorption by the positive electrode 3.

[0043] The multiple filled weights show that the filled weight of the battery of Comparative Example 2 is greater than the filled weight of the battery of Comparative Example 1, indicating that the smaller the specific surface area of the electrolytic manganese dioxide used in the positive electrode 3, the better the packing property of the positive electrode 3. The multiple filled weights also show that the filled weight of the battery of Comparative Example 2 is greater than the filled weight of the battery of Comparative Example 3, indicating that the larger the apparent density of the graphite used in the positive electrode 3, the better the packing property of the positive electrode 3.

[0044] The multiple filling weights further show that the packing property of the positive electrode 3 of the batteries of Examples 1 to 8 is equal to or better than the packing property of the positive electrode 3 of the battery of Comparative Example 3. The multiple filling weights further show that the packing property of the positive electrode 3 of the batteries of Examples 2 to 4 and 6 to 8 is better than the packing property of the positive electrode 3 of the battery of Comparative Example 1. The multiple filling weights further show that the packing property of the positive electrode 3 of the battery of Example 8 is better than the packing property of the positive electrode 3 of the battery of Comparative Example 2.

[0045] The multiple first discharge test results correspond to multiple battery samples. A first discharge test result corresponding to a certain battery sample among the multiple first discharge test results indicates a result derived by performing a first discharge test on that battery sample. In the first discharge test performed on a certain battery sample, a one-hour discharge period is set every day until the battery voltage of that battery sample becomes smaller than the end voltage of 0.9 V, and the discharge time is derived. During the one-hour discharge period, the battery sample is electrically connected to a load so that the battery sample is discharged at a constant current of 100 mA. For the period other than the one-hour discharge period each day, the battery sample is electrically isolated from the load so that it does not discharge. The discharge time indicates the time the battery sample was discharging before the battery voltage of that battery sample became smaller than the end voltage of 0.9 V. The first discharge test result corresponding to a certain battery sample among the multiple first discharge test results indicates the value obtained by dividing the average discharge time of the nine batteries fabricated as that battery sample by the average discharge time of the nine batteries fabricated as the batteries of Comparative Example 1, and multiplying the result by 100. The multiple first discharge test results indicate that the larger the first discharge test result of a battery sample, the better the discharge performance under medium to light loads.

[0046] The results of the first discharge tests show that the result of the first discharge test for the battery of Comparative Example 2 is greater than that of the battery of Comparative Example 1, indicating that the discharge performance under medium to light loads is better for batteries with a smaller specific surface area of electrolytic manganese dioxide used in the positive electrode 3. The results of the first discharge tests show that the result of the first discharge test for the battery of Comparative Example 2 is greater than that of the battery of Comparative Example 1, indicating that the discharge performance under medium to light loads is better for batteries with a larger apparent density of graphite used in the positive electrode 3.

[0047] The multiple first discharge test results show that the first discharge test results of the batteries of Examples 1 to 8 are equal to or greater than the first discharge test result of the battery of Comparative Example 3. The multiple first discharge test results further show that the first discharge test results of the batteries of Examples 2 to 4 and 6 to 8 are greater than the first discharge test result of the battery of Comparative Example 1. The multiple first discharge test results further show that the first discharge test result of the battery of Example 7 is greater than the first discharge test result of the batteries of Comparative Examples 1 to 3.

[0048] Furthermore, the results of the first discharge test and the results of the evaluation of the loading weight show that the better the packing property of the positive electrode 3 of a battery, the better the discharge performance under a medium to light load.

[0049] The multiple second discharge test results correspond to multiple battery samples. A second discharge test result corresponding to a certain battery sample among the multiple second discharge test results indicates a result derived by performing a second discharge test on that battery sample. In the second discharge test performed on a certain battery sample, an 8-hour discharge test is repeatedly performed daily until the battery voltage of the battery sample becomes smaller than the end voltage of 1.1 V, and the discharge time is derived. In the 8-hour discharge test, a 1-hour discharge pattern is repeatedly performed eight times. The 1-hour discharge pattern includes a 2-minute discharge period. During the 2-minute discharge period, the battery sample is electrically connected to a load so that the battery sample is continuously discharged at a constant current of 750 mA. During the rest period excluding the 2-minute discharge period during which the second discharge test is performed, the battery sample is electrically isolated from the load to prevent discharge. The discharge time indicates the time the battery sample was discharging before the battery voltage of the battery sample became smaller than the end voltage of 1.1 V. The second discharge test result corresponding to a certain battery sample among the multiple second discharge test results indicates the value obtained by dividing the average discharge time of the nine batteries fabricated as that battery sample by the average discharge time of the nine batteries fabricated as the batteries of Comparative Example 1, and multiplying the result by 100. The multiple second discharge test results indicate that the larger the second discharge test result of a battery sample, the better the discharge performance under heavy load.

[0050] The results of the second discharge tests show that the second discharge test result of the battery of Comparative Example 1 is greater than that of the battery of Comparative Example 2, indicating that the larger the specific surface area of the electrolytic manganese dioxide used in the positive electrode 3, the better the discharge performance under heavy load.The results of the second discharge tests show that the second discharge test result of the battery of Comparative Example 3 is greater than that of the battery of Comparative Example 2, indicating that the smaller the apparent density of the graphite used in the positive electrode 3, the better the discharge performance under heavy load.

[0051] The multiple first discharge test results and the multiple second discharge test results show that the discharge performance under medium to light loads of the battery of Comparative Example 1 is better than that of the battery of Comparative Example 2, but that the discharge performance under heavy loads of the battery of Comparative Example 1 is worse than that of the battery of Comparative Example 2. In other words, the multiple first discharge test results and the multiple second discharge test results show that when the second granulation mixture is formed in the same manner as the first granulation mixture, improving the discharge performance under medium to light loads of the battery may deteriorate the discharge performance under heavy loads of the battery.

[0052] The multiple first discharge test results and the multiple second discharge test results further show that the discharge performance under heavy load of the battery of Comparative Example 3 is better than that of the battery of Comparative Example 2, but that the discharge performance under medium to light load of the battery of Comparative Example 3 is worse than that of the battery of Comparative Example 2. In other words, the multiple first discharge test results and the multiple second discharge test results show that when the second granulation mixture is formed in the same manner as the first granulation mixture, improving the discharge performance under heavy load of the battery may deteriorate the discharge performance under medium to light load of the battery.

[0053] The multiple first discharge test results and the multiple second discharge test results further show that the discharge performance under both medium to light loads and heavy loads of the batteries of Examples 1 to 3 are better than that of the battery of Comparative Example 3. That is, the multiple first discharge test results and the multiple second discharge test results show that when the second specific surface area is different from the first specific surface area and the second apparent density is different from the first apparent density, the discharge performance under heavy loads can be improved without deteriorating the discharge performance under medium to light loads.

[0054] The multiple first discharge test results and the multiple second discharge test results further show that the discharge performance under medium to light loads of the battery of Example 4 is equal to that of the battery of Comparative Example 2, and that the discharge performance under heavy loads of the battery of Example 4 is better than that of the battery of Comparative Example 2. That is, the multiple first discharge test results and the multiple second discharge test results show that when the second specific surface area is different from the first specific surface area and the second apparent density is different from the first apparent density, the discharge performance under medium to light loads can be improved without deteriorating the discharge performance under heavy loads.

[0055] The multiple first discharge test results and the multiple second discharge test results further show that the discharge performance under both medium to light loads and heavy loads of the batteries of Examples 5 to 7 are better than that of the battery of Comparative Example 3. That is, the multiple first discharge test results and the multiple second discharge test results show that when the second average particle size is different from the first average particle size and the second apparent density is different from the first apparent density, the discharge performance under heavy loads can be improved without deteriorating the discharge performance under medium to light loads.

[0056] The multiple first discharge test results and the multiple second discharge test results further show that the discharge performance under medium to light loads of the battery of Example 8 is equal to that of the battery of Comparative Example 2, and that the discharge performance under heavy loads of the battery of Example 4 is both better than that of the battery of Comparative Example 2. In other words, the multiple first discharge test results and the multiple second discharge test results show that when the second average particle size is different from the first average particle size and the second apparent density is different from the first apparent density, the discharge performance under medium to light loads can be improved without deteriorating the discharge performance under heavy loads.

[0057] The results of the first discharge tests show that the discharge performance of the battery of Example 1 under medium-light load is worse than that of the battery of Comparative Example 1 under medium-light load, and that the discharge performance of the batteries of Examples 2 to 4 under medium-light load is better than that of the battery of Comparative Example 1 under medium-light load. That is, the results of the first discharge tests show that the discharge performance of the battery of Example 1 under medium-light load is worse than that of the battery of Comparative Example 1 under medium-light load. 2 / g or more, or the apparent density of the graphite is 0.01g / cm 3 The above indicates that the battery 1 has favorable discharge performance under medium to light loads.

[0058] The results of the first discharge tests show that the discharge performance under medium-light load of the battery of Example 5 is worse than that of the battery of Comparative Example 1, and that the discharge performance under medium-light load of the batteries of Examples 6 to 8 is better than that of the battery of Comparative Example 1. That is, the results of the first discharge tests show that the average particle size of the electrolytic manganese dioxide is 35 μm or more, or the apparent density of the graphite is 0.01 g / cm 3 The above indicates that the battery has favorable discharge performance under medium to light loads.

[0059] The results of the first discharge tests show that the discharge performance under heavy load of the battery of Example 4 is worse than that of the battery of Comparative Example 1, and that the discharge performance under heavy load of the batteries of Examples 1 to 3 is better than that of the battery of Comparative Example 1. That is, the results of the first discharge tests show that the specific surface area of the electrolytic manganese dioxide is 38 m 2 / g or less, or the apparent density of the graphite is 0.15g / cm 3 This indicates that the above condition is preferable in terms of the discharge performance under heavy load of the battery.

[0060] The results of the first discharge tests show that the discharge performance under heavy load of the battery of Example 8 is worse than that of the battery of Comparative Example 1, and that the discharge performance under heavy load of the batteries of Examples 5 to 7 is better than that of the battery of Comparative Example 1. That is, the results of the first discharge tests show that the average particle size of the electrolytic manganese dioxide is 55 μm or less, or the apparent density of the graphite is 0.15 g / cm 3 This indicates that the above is preferable in terms of the discharge performance of the battery under medium to light loads.

[0061] [Effects of the battery manufacturing method according to the embodiment] A battery manufacturing method according to an embodiment includes granulating a first granulated mixture using a first electrolytic manganese dioxide and a first graphite, granulating a second granulated mixture using a second electrolytic manganese dioxide different from the first electrolytic manganese dioxide and a second graphite different from the first graphite, and molding the mixture produced by mixing the first granulated mixture and the second granulated mixture into a positive electrode 3. In the battery manufacturing method according to an embodiment, the positive electrode 3 is produced from a mixture of the first granulated mixture and the second granulated mixture that are separately produced, and therefore it is possible to improve the discharge performance of the battery 1 under medium to light loads and the discharge performance under heavy loads without deteriorating the other.

[0062] In the battery manufacturing method of the embodiment, the specific surface area of the second electrolytic manganese dioxide is larger than the specific surface area of the first electrolytic manganese dioxide, or the average particle size of the second electrolytic manganese dioxide is larger than the average particle size of the first electrolytic manganese dioxide. In this case, it is preferable that the apparent density of the second graphite is larger than the apparent density of the first graphite.

[0063] In addition, the specific surface area of the first electrolytic manganese dioxide in the battery manufacturing method of the embodiment is 25 m 2 / g or more and 30m 2 / g or less. The specific surface area of the second electrolytic manganese dioxide is 33m 2 / g or more and 38m 2 In the battery manufacturing method of the embodiment, the specific surface area of the first electrolytic manganese dioxide is 25 m 2 / g or more, deterioration of discharge performance of the battery 1 under medium to light loads can be further suppressed. 2 / g or less, deterioration of the discharge performance of the battery 1 under heavy load can be further suppressed.

[0064] In the battery manufacturing method of the embodiment, the first electrolytic manganese dioxide has an average particle size of 35 μm or more and 45 μm or less. The second electrolytic manganese dioxide has an average particle size of 46 μm or more and 55 μm or less. In the battery manufacturing method of the embodiment, the first electrolytic manganese dioxide has an average particle size of 35 μm or more, which can further suppress deterioration of the discharge performance of the battery 1 under medium to light loads. In the battery manufacturing method of the embodiment, the first electrolytic manganese dioxide has an average particle size of 55 μm or less, which can further suppress deterioration of the discharge performance of the battery 1 under heavy loads.

[0065] In addition, the apparent density of the first graphite in the battery manufacturing method of the embodiment is 0.01 g / cm 3 or more and 0.05 g / cm 3 The apparent density of the second graphite is 0.06 g / cm 3 or more and 0.15 g / cm 3 In the battery manufacturing method of the embodiment, the apparent density of the first graphite is 0.01 g / cm 3 This makes it possible to further suppress deterioration of the discharge performance of the battery 1 under medium to light loads. 3 By satisfying this condition, deterioration of the discharge performance of the battery 1 under heavy load can be further suppressed.

[0066] In the battery manufacturing method of the embodiment described above, the specific surface area or average particle size of the electrolytic manganese dioxide and the apparent density of the graphite are different between the first granulation mixture and the second granulation mixture, but other parameters of the electrolytic manganese dioxide or the graphite may be different. Even in this case, the battery manufacturing method of the embodiment makes it possible to improve the discharge performance of the battery 1 under medium to light loads and the discharge performance under heavy loads without deteriorating the other, because the positive electrode 3 is made from a mixture of the first granulation mixture and the second granulation mixture that are separately prepared.

[0067] Although the embodiments have been described above, the embodiments are not limited to the above content. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, at least one of various omissions, substitutions, and modifications of the components can be made without departing from the spirit of the embodiments. [Explanation of symbols]

[0068] 1:Battery 3: Positive electrode 5: Negative electrode

Claims

1. granulating a first granulated mixture using the first electrolytic manganese dioxide and the first graphite; granulating a second granulated mixture using the second electrolytic manganese dioxide and the second graphite; and molding the mixture produced by mixing the first granulated mixture and the second granulated mixture into a positive electrode. the specific surface area of the second electrolytic manganese dioxide is larger than the specific surface area of the first electrolytic manganese dioxide; The apparent density of the second graphite is greater than the apparent density of the first graphite. Battery manufacturing method.

2. The specific surface area of the first electrolytic manganese dioxide is 25 m ２ / g or more and 30m ２ / g or less, The specific surface area of the second electrolytic manganese dioxide is 33 m ２ / g or more and 38m ２ / g or less, the apparent density of the first graphite is 0.01 g / cm 3 or more and 0.05 g / cm 3 or less; The apparent density of the second graphite is 0.06 g / cm 3 or more and 0.15 g / cm 3 or less. The battery manufacturing method according to claim 1 .

3. Granulating a first granulated mixture using first electrolytic manganese dioxide and first graphite; granulating a second granulated mixture using the second electrolytic manganese dioxide and the second graphite; and molding the mixture produced by mixing the first granulated mixture and the second granulated mixture into a positive electrode. the average particle size of the second electrolytic manganese dioxide is larger than the average particle size of the first electrolytic manganese dioxide, The apparent density of the second graphite is greater than the apparent density of the first graphite. Battery manufacturing method.

4. the first electrolytic manganese dioxide has an average particle size of 35 μm or more and 45 μm or less; the second electrolytic manganese dioxide has an average particle size of 46 μm or more and 55 μm or less; the apparent density of the first graphite is 0.01 g / cm 3 or more and 0.05 g / cm 3 or less; The apparent density of the second graphite is 0.06 g / cm 3 or more and 0.15 g / cm 3 or less. The battery manufacturing method according to claim 3 .

5. Granulating a first granulated mixture using first electrolytic manganese dioxide and first graphite; granulating a second granulated mixture using the second electrolytic manganese dioxide and the second graphite; and molding the mixture produced by mixing the first granulated mixture and the second granulated mixture into a positive electrode. the specific surface area of the first electrolytic manganese dioxide is 25 m 2 / g or more and 30 m 2 / g or less; the specific surface area of the second electrolytic manganese dioxide is greater than the specific surface area of the first electrolytic manganese dioxide, being 33 m 2 / g or more and 38 m 2 / g or less; the first electrolytic manganese dioxide has an average particle size of 35 μm or more and 45 μm or less; the average particle size of the second electrolytic manganese dioxide is larger than the average particle size of the first electrolytic manganese dioxide, being 46 μm or more and 55 μm or less; the apparent density of the first graphite is 0.01 g / cm 3 or more and 0.05 g / cm 3 or less; The apparent density of the second graphite is greater than the apparent density of the first graphite, and is 0.06 g / cm 3 or more and 0.15 g / cm 3 or less. Battery manufacturing method.

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