JP2008021446A - Alkaline dry cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a heavy load continuous discharge performance of an alkaline dry cell. <P>SOLUTION: The alkaline dry cell uses a positive electrode mixture 21 formed in a prescribed shape, a negative electrode mixture 23 of gel shape, and an alkaline electrolytic liquid. The water content contained in the positive electrode mixture 21 is made 9-11 wt.% and the water content contained in the negative electrode mixture is made 18-22 wt.%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an alkaline dry battery, and more particularly, to an alkaline dry battery using manganese dioxide and / or nickel oxyhydroxide as a positive electrode active substance and improving high-load discharge characteristics.

  General alkaline batteries such as LR are designed to satisfy discharge items defined by various standards (IEC, ANSI, JIS, etc.) (Non-Patent Document 1). However, recently, the demand for high-load continuous discharge performance has been increased due to the spread of battery-utilizing devices that require a large current, such as digital cameras. This requirement exceeds the level set by the standard.

  In addition, since alkaline dry batteries such as LR are finely stipulated by the standard of the outer size and the like, there are certain restrictions on the filling volume of power generation materials such as a positive electrode mixture and a negative electrode mixture. As a countermeasure for improving the capacity and discharging characteristics of the battery under this restriction, it has been proposed to increase the utilization efficiency of the active material (see Patent Document 1 and Non-Patent Document 1).

Regarding increasing the utilization efficiency of the active material, it is disclosed that the amount of water contained in the positive electrode mixture is 8.4 wt (wt)% to 10 wt%. This amount of water is a sufficient amount required for the discharge reaction, and the use efficiency of the positive electrode active material is increased by including this amount of water (Patent Document 1).
JP 2004-146294 A “Battery Handbook” issued by Asakura Shoten

  However, the utilization efficiency of the active material and the discharge performance are not always compatible, and even if the utilization rate of the active material can be increased, there is no guarantee that the discharge performance will be improved thereby, but there may be a contradiction. In particular, when focusing attention on the performance for sustaining a large current discharge, so-called high-load continuous discharge performance, it has been clarified by the present inventors that it cannot be improved only by defining the amount of water contained in the positive electrode mixture.

  The present invention has been made in view of the above problems, and its purpose is to provide a high-performance alkaline dry battery using a positive electrode mixture, a gel-like negative electrode mixture, and an alkaline electrolyte formed into a predetermined shape. The purpose is to improve continuous load discharge performance.

  Other objects and configurations of the present invention will become apparent from the description of the present specification and the accompanying drawings.

The present invention provides the following solutions.
(1) An alkaline dry battery using a positive electrode mixture formed in a predetermined shape, a gel-like negative electrode mixture, and an alkaline electrolyte, wherein the amount of water contained in the positive electrode mixture is 9 wt% to 11 wt%. An alkaline battery characterized in that the amount of water contained in the mixture is 18 wt% to 22 wt%.
(2) An alkaline dry battery characterized in that in the above means (1), manganese dioxide and / or nickel oxyhydroxide is used as the positive electrode active substance of the positive electrode mixture.
(3) An alkaline dry battery characterized in that, in the above means (1) or (2), the positive electrode mixture and the negative electrode mixture contain polyacrylic acid having an alkali resistance and a water absorption function or a salt thereof.

  In an alkaline dry battery using a positive electrode mixture, a gel-like negative electrode mixture, and an alkaline electrolyte formed into a predetermined shape, high-load continuous discharge performance can be improved.

  Operations / effects other than those described above will be apparent from the description of the present specification and the accompanying drawings.

  FIG. 1 shows an embodiment of an LR alkaline battery 10 to which the technology of the present invention is applied. The dry battery 10 shown in the figure is an alkaline primary battery, and comprises a positive electrode mixture 21, a separator 22, and a gel-like negative electrode mixture 23 formed in a predetermined shape in a bottomed cylindrical metal positive electrode can 11. The power generation element 20 is accommodated together with the alkaline electrolyte.

  The positive electrode can 11 is a deep-drawn nickel-plated steel plate. The positive electrode can 11 also serves 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 opening of the positive electrode can 11 is sealed using a negative electrode terminal plate 32 and a resin gasket 35. A rod-shaped negative electrode current collector 31 is fixed inside the negative electrode terminal plate 32, and the current collector 31 is inserted into the gel-like negative electrode mixture 23.

  The positive electrode mixture 21 is formed by adding a conductive additive such as graphite to a positive electrode active material (positive electrode active material) into a tubular shape, and the positive electrode active material (positive electrode active material) includes manganese dioxide ( EMD etc.) or nickel oxyhydroxide, or a mixture of both. For the negative electrode mixture 23, gelled zinc using zinc alloy powder is used.

  The structural configuration of the battery is basically the same as the conventional one. The feature of the battery of the present invention that is different from the conventional one is that the amounts of water contained in the positive electrode mixture 21 and the negative electrode mixture 23 are defined within a certain range. That is, the water contained in the positive electrode mixture 21 is defined in the range of 9 wt (weight)% to 11 wt%, and the water contained in the negative electrode mixture 23 is defined in the range of 18 wt% to 22 wt%.

  The amount of water is the amount of water in a state assembled in the battery, and is an amount with respect to the weight of the mixture including the electrolytic solution. In this embodiment, the positive electrode mixture 21 and the negative electrode mixture 23 are made to contain polyacrylic acid or polyacrylate having an alkali resistance and a water absorption function in order to ensure that the water content is contained. Since polyacrylic acid or polyacrylate is a water retaining agent capable of retaining a large amount of water, the addition to the mixture 21, 23 may be negligibly small relative to the total weight of the mixture.

  As described above, by setting the water contents of the positive electrode mixture 21 and the negative electrode mixture 23 within the above ranges (9 wt% to 11 wt% and 18 wt% to 22 wt%), respectively, the high-load continuous discharge performance is greatly improved compared to the conventional case. Has been found to be improved.

  In addition, the positive electrode mixture 21 and the negative electrode mixture 23 contain polyacrylic acid or polyacrylate having an alkali resistance and a water absorption function, so that the positive electrode mixture 21 has the above-described water content (9 wt% to 11 wt%). ), The shape retention of the mixture shape was kept good. The negative electrode mixture 23 was also able to contain the above water content (9 wt% to 11 wt%) without hindering the contact with the negative electrode current collector 31. Since the contact with the current collector 31 is stabilized, abnormal discharge is also prevented.

  Specific examples of the present invention will be described below.

  In the LR20 alkaline battery 10 having the structure shown in FIG. 1, test batteries were produced in which the water content of the positive electrode mixture 21 and the water content of the negative electrode mixture 23 were different from each other. For each test battery, the discharge duration with a 1Ω load (end voltage was 0.9 V) was measured, and the results shown in Table 1 were obtained.

<Table 1>

  Moreover, FIG. 2 shows the transition of the discharge duration when the moisture content of the negative electrode mixture 23 is varied for each moisture content of the positive electrode mixture 21.

  As described above, not only the water content of the positive electrode mixture 21 but also the water content of the negative electrode mixture 23 acts as an important parameter element for the discharge duration.

  Furthermore, as shown in Table 2, the high load continuous discharge performance is greatly improved as compared with the prior art by setting the moisture content of both mixtures 21 and 23 to 9 wt% to 11 wt% and 18 wt% to 22 wt%. Yes.

<Table 2>

  Table 2 shows the discharge performance evaluated in three stages of △△ ×, but all the test batteries in the above water content range (9 wt% to 11 wt% and 18 wt% to 22 wt%) are subjected to high load continuous discharge. It was confirmed that the performance was improved.

  As described above, the present invention has been described based on the typical embodiments. However, the present invention can have various modes other than those described above. For example, the present invention is particularly effective when applied to an alkaline battery using manganese dioxide and / or nickel oxyhydroxide as a positive electrode active substance, but can also be applied to an alkaline dry battery using a positive electrode active substance other than the above. is there.

  In an alkaline dry battery using a positive electrode mixture, a gel-like negative electrode mixture, and an alkaline electrolyte formed into a predetermined shape, high-load continuous discharge performance can be improved.

It is sectional drawing which shows one Embodiment of the alkaline dry battery to which the technique by this invention was applied. It is a graph which shows the relationship between the moisture content of a positive electrode mixture and a negative electrode mixture, and discharge performance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Alkaline battery 11 Positive electrode can 12 Positive electrode terminal part 20 Electric power generation element 21 Positive electrode mixture 22 Separator 23 Negative electrode mixture (Use zinc alloy powder)
31 Negative current collector 32 Negative electrode terminal plate 35 Gasket

Claims (3)

  An alkaline dry battery using a positive electrode mixture, a gel-like negative electrode mixture, and an alkaline electrolyte formed into a predetermined shape, wherein the amount of water contained in the positive electrode mixture is 9 wt% to 11 wt%. An alkaline battery characterized in that the amount of water contained is 18 wt% to 22 wt%.   2. The alkaline dry battery according to claim 1, wherein manganese dioxide and / or nickel oxyhydroxide is used as the positive electrode active substance of the positive electrode mixture. The alkaline dry battery according to claim 1 or 2, wherein the positive electrode mixture and the negative electrode mixture contain polyacrylic acid or a salt thereof having an alkali resistance and a water absorption function.

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