JP2015141889A - Alkali battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkali battery superior in heavy load discharge performance.SOLUTION: An alkali battery 1 comprises: a positive electrode mixture 21 put in a bottomed cylindrical positive electrode can 11; a separator 22 provided on the inner peripheral side of the positive electrode mixture 21; a negative electrode mixture 23 including powder including zinc as a primary component, and filled on the inner peripheral side of the separator 22; a negative electrode current collector 31 inserted in the negative electrode mixture 23; a negative electrode terminal plate 32 for sealing the opening of the positive electrode can 11; and an electrolytic solution including a potassium hydroxide. The concentration of potassium hydroxide included in the positive electrode mixture 21 is made larger than the concentration of potassium hydroxide included in the negative electrode mixture 23. As the powder, powder including particles having a particle size of 75 μm or less by 25-40 mass% is used. It is more preferable that the potassium hydroxide concentration of the positive electrode mixture 21 is in a range of 35-50 mass%, and the potassium hydroxide concentration of the negative electrode mixture 23 is in a range of 30-45 mass%.

Description

  The present invention relates to a technique for improving discharge performance, particularly heavy load discharge performance, of an alkaline battery.

  In recent years, electronic devices such as digital cameras, video cameras, mobile phones, smartphones and the like have been improved in performance and size, and demands for improving the performance of alkaline batteries used as power sources for such electronic devices are increasing.

  Regarding the improvement of the performance of alkaline batteries, Patent Document 1 discloses that a positive binder is used for maintaining discharge performance without adding a special binder and improving the yield of cylindrical alkaline batteries by improving the strength of positive electrode pellets. The concentration of the alkaline electrolyte is higher than that of the alkaline electrolyte for pouring, particularly the concentration of the electrolyte for positive electrode mixture is 45 to 50 wt%, the concentration of the electrolytic solution for pouring is 35 to 40 wt%, It is described that the concentration is 5 wt% or more higher than the latter.

  In Patent Document 2, manganese dioxide or manganese dioxide is provided in order to provide an alkaline battery that has excellent load characteristics and prevents gas generation and storage stability from being reduced by reaction with an electrolytic solution, while suppressing heat generation behavior when an abnormality occurs. A positive electrode mixture containing nickel oxide, a conductive agent and an alkaline electrolyte (A) in which potassium hydroxide is dissolved; a separator; an alkaline electrolyte (B) in which zinc alloy powder, a gelling agent and potassium hydroxide are dissolved; An alkaline battery prepared by encapsulating an alkaline electrolyte (C) in which potassium hydroxide is dissolved in an exterior body, and after the battery is assembled, the alkaline electrolyte in the battery system The potassium hydroxide concentration of the electrolytes (A) to (C) is adjusted so that the average potassium hydroxide concentration is 30 to 37% by mass, and a 200 mesh sieve is passed through the negative electrode. That the ratio of the powders is describes the use of zinc alloy powder is 4-40 weight%.

JP 2002-15748 A JP 2007-115701 A

  Patent Document 1 describes that the concentration of the alkaline electrolyte for positive electrode mixture is adjusted for the purpose of maintaining the discharge performance and improving the strength of the positive electrode pellet. In particular, improvement in performance at the time of heavy load discharge in which the utilization factor of the active material decreases is not considered. Patent Document 2 describes that the potassium hydroxide concentration of the alkaline electrolyte in the battery system is adjusted in order to improve the load characteristics of the alkaline battery, but particularly mentions the improvement of heavy load discharge performance. It has not been.

  The present invention has been made for the purpose of improving the discharge performance of an alkaline battery, and particularly has an object of providing an alkaline battery excellent in heavy load discharge performance.

  One aspect of the present invention for achieving the above object is that a positive electrode mixture loaded in a bottomed cylindrical positive electrode can, a separator provided on the inner peripheral side of the positive electrode mixture, and an inner periphery of the separator A negative electrode mixture containing zinc-based powder, a negative electrode current collector inserted into the negative electrode mixture, a negative electrode terminal plate that seals the opening of the positive electrode can, and hydroxylation An alkaline battery comprising an electrolyte containing potassium, wherein the concentration of the potassium hydroxide contained in the cathode mixture is the concentration of the potassium hydroxide contained in the anode mixture It is characterized in that the powder contains particles having a particle size of 75 μm or less in a range of 25 to 40% by mass.

  Moreover, another one of this invention is the said alkaline battery, Comprising: The density | concentration of the said potassium hydroxide contained in the said positive electrode mixture is 35-50 mass%, and is contained in the said negative electrode mixture. The potassium hydroxide concentration is in the range of 30 to 45% by mass.

  Another aspect of the present invention is the alkaline battery, wherein the powder contains bismuth in a range of 0.01 to 0.03% by mass.

  In addition, the subject which this application discloses, and its solution method are clarified by the column of the form for inventing, and drawing.

  ADVANTAGE OF THE INVENTION According to this invention, the alkaline battery excellent in discharge performance, especially heavy load discharge performance can be provided.

It is a figure which shows the structure of a general cylindrical alkaline battery.

  FIG. 1 shows a configuration of a general cylindrical alkaline battery (LR6 type (AA) alkaline battery) (hereinafter referred to as alkaline battery 1) to which the present invention is applied. In the figure, the alkaline battery 1 is shown as a vertical cross-sectional view (a cross-sectional view when the extending direction of the cylindrical shaft is the vertical (vertical) direction).

  As shown in FIG. 1, the alkaline battery 1 includes a bottomed cylindrical metal battery can (hereinafter referred to as a positive electrode can 11), a positive electrode mixture 21 inserted into the positive electrode can 11, and a positive electrode mixture 21. A bottomed cylindrical separator 22 provided on the inner peripheral side, a negative electrode mixture 23 filled on the inner peripheral side of the separator 22, and a negative electrode fitted into the opening of the positive electrode can 11 via a resin sealing gasket 35 A terminal plate 32 and a rod-shaped negative electrode current collector 31 made of a material such as brass, which is fixed inside the negative electrode terminal plate 32 by spot welding or the like, are provided. The positive electrode mixture 21, the separator 22, and the negative electrode mixture 23 constitute the power generation element 20 of the alkaline battery 1.

  The positive electrode can 11 is made of a conductive material. For example, a material obtained by pressing a metal material such as a nickel-plated steel plate is used. The positive electrode can 11 also functions as a positive electrode current collector and a positive electrode terminal, and a convex positive electrode terminal portion 12 is integrally formed at the bottom thereof.

  The positive electrode mixture 21 is a mixture of electrolytic manganese dioxide (EMD) as a positive electrode active material, graphite as a conductive material, and an electrolytic solution mainly composed of potassium hydroxide (KOH) together with a binder such as polyacrylic acid, The mixture is processed in steps such as rolling, crushing, granulating, and classifying, and then compressed into a ring shape. As shown in the figure, in the positive electrode can 11, a plurality of annular positive electrode mixtures 21 are stacked in the vertical direction and press-fitted so as to be coaxial with the cylindrical axis of the positive electrode can 11. In the alkaline battery 1 of FIG. 1, three positive electrode mixtures 21 are pressed into a positive electrode can 11.

  The negative electrode mixture 23 is a gelled zinc alloy powder as a negative electrode active material. Zinc alloy powder is powdered by gas atomization method or centrifugal spray method, zinc, alloy components added for the purpose of suppressing gas generation (leakage prevention), etc. (bismuth, aluminum, indium, etc.), And potassium hydroxide as an electrolyte. The negative electrode current collector 31 is inserted into the central portion of the negative electrode mixture 23.

  About the alkaline battery 1 which consists of the above structure, the following tests 1-3 were performed in order to verify the improvement effect of discharge performance, especially heavy load discharge performance.

<Test 1>
In Test 1, the concentration of potassium hydroxide in the positive electrode mixture 21 and the concentration of potassium hydroxide in the negative electrode mixture 23 were both changed in the range of 30 to 50% by mass, and the particle size of the zinc alloy powder of the negative electrode mixture 23 was changed. A plurality of types of alkaline batteries 1 were prepared using those containing 10% by mass of particles having a particle size of 75 μm or less and those containing 30% by mass, and their discharge performances were compared. The comparison of discharge performance is based on a cycle discharge test assuming heavy load discharge when using a digital camera (2 discharges at 1500 mW, discharge for 28 seconds at 650 mW 10 times per hour (rest time 55 per hour) Min)), and the number of cycles up to the end voltage (1.05 V) was counted and compared.

  Table 1 shows the result of comparing the discharge performance of each alkaline battery 1. The numerical values in the table showing the discharge performance are 40% by mass of the potassium hydroxide concentration of the positive electrode mixture 21, 40% by mass of the potassium hydroxide concentration of the negative electrode mixture 23, and the zinc alloy powder of the negative electrode mixture 23. Is a relative value when the discharge performance of the alkaline battery 1 produced using 40% by mass of particles having a particle size of 75 μm or less is 100 (numerical value underlined). Numbers that have a relatively high improvement effect are marked with a frame.

表１に示すように、正極合剤２１の水酸化カリウムの濃度 (３５〜５０質量％)が負極合剤２３の水酸化カリウムの濃度 (３０〜４５質量％)よりも大きい場合に放電性能が高くなることが確認された。また粒径の小さな亜鉛合金粉末をより多く用いた場合（同表では粒度が７５μｍ以下の粒子を３０質量％含むもの）にとくに放電性能が高くなることが確認された。このように放電性能が向上するのは、負極合剤２３に粒径の小さな亜鉛合金粉末を用い、かつ、負極合剤２３の水酸化カリウムの濃度を低減することによって電解液（水）の供給がスムーズになり、パルス放電性能が向上するためであると考えられる。

As shown in Table 1, when the potassium hydroxide concentration (35 to 50% by mass) of the positive electrode mixture 21 is larger than the potassium hydroxide concentration (30 to 45% by mass) of the negative electrode mixture 23, the discharge performance is improved. It was confirmed that it would be higher. In addition, it was confirmed that the discharge performance was particularly improved when a larger amount of zinc alloy powder having a smaller particle size was used (in the same table, particles containing 30% by mass of particles having a particle size of 75 μm or less). Thus, the discharge performance is improved by using a zinc alloy powder having a small particle size for the negative electrode mixture 23 and reducing the concentration of potassium hydroxide in the negative electrode mixture 23 to supply the electrolytic solution (water). This is considered to be smooth and improve the pulse discharge performance.

  When the concentration of potassium hydroxide in the positive electrode mixture 21 is less than 35% by mass, the strength of the positive electrode mixture 21 decreases, and the positive electrode mixture 21 is inserted into the positive electrode can 11 in the step of inserting the positive electrode mixture 21 into the positive electrode mixture 21. Cracking occurred. In addition, when the concentration of potassium hydroxide in the positive electrode mixture 21 exceeded 50% by mass, potassium hydroxide precipitated at room temperature, making it difficult to produce a uniform positive electrode mixture 21.

  Further, when the concentration of potassium hydroxide in the negative electrode mixture 23 was less than 30% by mass, the oxidation of the negative electrode gel was facilitated, and it was difficult to produce a uniform negative electrode gel. When the concentration of potassium hydroxide in the negative electrode mixture 23 exceeds 45% by mass, the viscosity of the negative electrode mixture 23 becomes too high, and the negative electrode mixture 23 is injected into the separator 22 in the step of injecting the negative electrode mixture 23 into the separator 22. The fluidity became insufficient.

<Test 2>
Subsequently, in order to verify an appropriate range as the particle size of the zinc alloy powder of the negative electrode mixture 23, the particle size of the zinc alloy powder of the negative electrode mixture 23 was changed (the content ratio of particles having a particle size of 75 μm or less is 24 to 41 mass). A plurality of types of alkaline batteries 1 (changed in the range of%) were prepared, and the discharge performance and the amount of gas generated in the batteries were compared. In addition, the combination of the concentration of potassium hydroxide in the positive electrode mixture 21 and the concentration of potassium hydroxide in the negative electrode mixture 23 was changed (provided that “the concentration of potassium hydroxide in the positive electrode mixture 21> the hydroxylation in the negative electrode mixture 23). Maintaining the relationship of “potassium concentration”) A plurality of types of alkaline batteries 1 were prepared, and the discharge performance and the amount of gas generated in the battery were compared when the particle size of the zinc alloy powder of the negative electrode mixture 23 was changed. Further, as a conventional example, the concentration of potassium hydroxide in the positive electrode mixture 21 and the concentration of potassium hydroxide in the negative electrode mixture 23 are matched (both 40% by mass), and the particle size of the zinc alloy powder of the negative electrode mixture 23 is reduced. An alkaline battery 1 was prepared using a particle containing 10% by mass of particles of 75 μm or less, and the discharge performance and the amount of gas generated in the battery were compared. The discharge performance was determined by the same method as described above. Regarding the amount of gas generated in the battery, the amount of gas generated in the battery after the produced alkaline battery 1 was stored at 90 ° C. for 15 days was measured.

  Table 2 shows the results of comparing the discharge performance of each alkaline battery 1 and the amount of gas generated in the battery. The numerical values representing the discharge performance and the amount of gas generated in the battery are 40% by mass of the potassium hydroxide concentration of the positive electrode mixture 21, 40% by mass of the potassium hydroxide concentration of the negative electrode mixture 23, and the negative electrode. The discharge performance of the alkaline battery 1 produced using the zinc alloy powder of the mixture 23 containing 10% by mass of particles having a particle size of 75 μm or less and the value of the gas in the battery were both set to 100 (values underlined). Relative value. Numbers that have a relatively high improvement effect are marked with a frame.

表２に示すように、負極合剤２３の亜鉛合金粉末として粒度が７５μｍ以下の粒子を２５〜４０質量％の範囲で含むものを用いて作製したアルカリ電池１（実施例Ａ１〜Ａ３，Ｂ１〜Ｂ３，Ｃ１〜Ｃ３）については、放電性能が従来例よりも１０％以上向上し、かつ、電池内ガスの発生量は従来例と同程度であることが確認された。また負極合剤２３の亜鉛合金粉末として粒度が７５μｍ以下の粒子の含有率が２５質量％未満であるものを用いて作製したアルカリ電池１（比較例Ａ１，Ｂ１，Ｃ１）については、放電性能の改善効果が不充分であることが確認された。また負極合剤２３の亜鉛合金粉末として粒度が７５μｍ以下の粒子の含有率が４０質量％を超えるものを用いて作製したアルカリ電池１（比較例Ａ２，比較例Ｂ２，比較例Ｃ２）については、電池内ガスの発生量が多く耐漏液性能が低下することが確認された。

As shown in Table 2, alkaline batteries 1 (Examples A1 to A3, B1 to B1) prepared using zinc alloy powder of the negative electrode mixture 23 containing particles having a particle size of 75 μm or less in a range of 25 to 40% by mass. Regarding B3, C1 to C3), it was confirmed that the discharge performance was improved by 10% or more than the conventional example, and the amount of gas in the battery was the same as that of the conventional example. Moreover, about the alkaline battery 1 (comparative example A1, B1, C1) produced using the zinc alloy powder of the negative electrode mixture 23 whose particle size is 75 micrometers or less and whose content rate is less than 25 mass%, it is of discharge performance. It was confirmed that the improvement effect was insufficient. Moreover, about the alkaline battery 1 (Comparative Example A2, Comparative Example B2, Comparative Example C2) produced using the zinc alloy powder of the negative electrode mixture 23 having a particle size of 75 μm or less exceeding 40% by mass, It was confirmed that the amount of gas generated in the battery was large and the leakage resistance performance deteriorated.

<Test 3>
Subsequently, in order to verify the composition (bismuth content) of the zinc alloy powder used as the negative electrode mixture 23, the composition (bismuth content) of the zinc alloy powder is changed (the content of bismuth is 0.009 to 0.031 mass). And a plurality of types of alkaline batteries 1 in which the particle size of the zinc alloy powder was changed (the content of particles having a particle size of 75 μm or less was changed between 25 and 40% by mass), The discharge performance and the amount of gas generated in the battery were compared. In addition, about all these, it was set as the relationship of "the density | concentration (50 mass%) of potassium hydroxide of the positive electrode mixture 21> the density | concentration (30 mass%) of potassium hydroxide of the negative electrode mixture 23". As a conventional example, the concentration of potassium hydroxide in the positive electrode mixture 21 and the concentration of potassium hydroxide in the negative electrode mixture 23 are matched (both 40% by mass), and the particle size of the negative electrode mixture 23 as zinc alloy powder is 75 μm or less. The alkaline battery 1 having a bismuth content of 0.007% by mass was prepared using a particle content of 10% by mass, and the discharge performance and the amount of gas generated in the battery were also compared. The discharge performance and the amount of gas generated in the battery were determined by the same method as described above.

  Table 3 shows the results of comparing the discharge performance of each alkaline battery 1 and the amount of gas generated in the battery. The numerical values representing the discharge performance and the gas in the battery in the table are as follows: the concentration of potassium hydroxide in the positive electrode mixture 21 is 40% by mass; the concentration of potassium hydroxide in the negative electrode mixture 23 is 40% by mass; It is a relative value when the discharge performance of the alkaline battery 1 produced using particles containing 10% by mass of particles having a particle size of 75 μm or less and the value of the gas in the battery are both 100 (underlined numerical value). Numbers that have a relatively high improvement effect are marked with a frame.

表３に示すように、負極合剤２３の亜鉛合金粉のビスマス含有量が０．００１０〜０．０３０質量％の範囲のアルカリ電池１（実施例Ａ１〜Ａ８）については電池内ガスの発生量は従来例と同程度であり、かつ、放電性能が従来例より１０％以上向上することを確認できた。また亜鉛合金粉のビスマス含有量が０．０１０質量％未満（従来例並びに比較例、Ａ３，Ａ５，Ａ７）では、電池内ガスの発生を抑制する効果が不充分であるため耐漏液性能が低下し、とくにビスマス含有量が０．０３０質量％を超えると放電性能が低下することが確認できた。

As shown in Table 3, for alkaline battery 1 (Examples A1 to A8) in which the bismuth content of the zinc alloy powder of negative electrode mixture 23 is in the range of 0.0010 to 0.030 mass%, the amount of gas generated in the battery Was comparable to the conventional example, and it was confirmed that the discharge performance was improved by 10% or more than the conventional example. In addition, when the bismuth content of the zinc alloy powder is less than 0.010% by mass (conventional examples and comparative examples, A3, A5, and A7), the effect of suppressing the generation of gas in the battery is insufficient, and the leakage resistance performance is reduced. In particular, it was confirmed that the discharge performance deteriorates when the bismuth content exceeds 0.030% by mass.

<Effect>
As described above, when the concentration of potassium hydroxide in the positive electrode mixture 21 is higher than the concentration of potassium hydroxide in the negative electrode mixture 23, the discharge performance of the alkaline battery 1 is increased, and further, as the zinc alloy powder of the negative electrode mixture 23. It was confirmed that the discharge performance of the alkaline battery 1 was greatly improved by using particles containing particles having a particle size of 75 μm or less in the range of 25 to 40% by mass.

  Further, high discharge performance can be obtained when the concentration of potassium hydroxide in the positive electrode mixture 21 is 35 to 50% by mass and the concentration of potassium hydroxide contained in the negative electrode mixture 23 is in the range of 30 to 45% by mass. Was confirmed.

  Moreover, it was confirmed that by using a zinc alloy powder used as the negative electrode mixture 23 containing bismuth in the range of 0.01 to 0.03% by mass, high discharge performance was obtained and leakage resistance was ensured. .

  In addition, the above description is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Alkaline battery, 11 Positive electrode can, 12 Positive electrode terminal part, 20 Power generation element, 21 Positive electrode mixture, 22 Separator, 23 Negative electrode mixture, 31 Negative electrode current collector, 32 Negative electrode terminal plate, 35 Sealing gasket

Claims (3)

A positive electrode mixture loaded in a bottomed cylindrical positive electrode can; a separator provided on an inner peripheral side of the positive electrode mixture; and a powder containing zinc as a main component, which is filled on the inner peripheral side of the separator. An alkali comprising: a negative electrode mixture comprising: a negative electrode current collector inserted into the negative electrode mixture; a negative electrode terminal plate sealing the opening of the positive electrode can; and an electrolyte containing potassium hydroxide. A battery,
The concentration of the potassium hydroxide contained in the positive electrode mixture is greater than the concentration of the potassium hydroxide contained in the negative electrode mixture;
An alkaline battery, wherein the powder contains particles having a particle size of 75 μm or less in a range of 25 to 40% by mass. The alkaline battery according to claim 1,
The concentration of the potassium hydroxide contained in the positive electrode mixture is 35-50% by mass, and the concentration of the potassium hydroxide contained in the negative electrode mixture is in the range of 30-45% by mass. An alkaline battery. The alkaline battery according to claim 1 or 2,
The alkaline powder characterized in that the powder contains bismuth in a range of 0.01 to 0.03% by mass.

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