JP5366490B2 - Alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkaline cell excellent in shock resistance in spite of its excellent discharge performance. <P>SOLUTION: The alkaline cell 11 includes an anode collector 60 structured of a cathode can 21, a cathode mixture 31, a gel anode mixture 51, a separator 41 and a sealing gasket 81 among others. At an inner periphery edge part P1 at an opening side end face of the cathode mixture 31 arranged closest to the opening, a virtual line S1 is assumed parallel with a direction of a cell center axis line C1. A distance L1 from the inner periphery edge part P1 along the virtual line S1 to the sealing gasket 81 is to be 0 mm or more and 2.75 mm or less. The separator 41 is formed by using a separator material with a liquid retention rate of 250% or more and 350% or less and with a thickness of 230 &mu;m or more and 575 &mu;m or less. A volume of zinc powder in the gel anode mixture 51 is to be 2.00 g or more and 3.81 g or less. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an alkaline battery including a positive electrode can, a positive electrode mixture, a gelled negative electrode mixture, a separator, a negative electrode current collector, and the like.

In a conventional general alkaline battery, a ring-shaped positive electrode mixture is fitted into a bottomed cylindrical positive electrode can, and a gel-like negative electrode mixture is placed in a state where a separator is interposed in a hollow portion of the positive electrode mixture. It has a filled structure. The opening of the positive electrode can is sealed in a liquid-tight manner by a negative electrode current collector configured to include a sealing gasket, a current collector rod, a negative electrode terminal plate, and the like. In this type of alkaline battery, the discharge performance may be lowered when subjected to an impact. Thus, a technology has been proposed in which a part of the gelled negative electrode mixture is made into a high-viscosity negative electrode gel layer to suppress the flow of the gelled negative electrode mixture in the battery and improve impact resistance. (For example, refer to Patent Document 1).
Japanese Patent Application No. 2005-88710

  By the way, in recent years, many devices such as controllers for game machines that incorporate AA alkaline batteries have appeared. However, depending on the usage situation (for example, when the device is dropped), the alkaline batteries are very large. An impact is expected. In such a case, the gelled negative electrode mixture moves to the negative electrode side due to the impact, and the specific portion of the separator (particularly, near the opening side end surface of the positive electrode mixture arranged closest to the opening) is broken. May occur. Then, as a result of the gelled negative electrode mixture leaking from the broken portion, an internal short circuit may occur, and the battery may generate heat.

  In recent years, the demand for impact resistance has become stricter as described above, while there is also a strong demand for improving the discharge performance by increasing the internal capacity of the alkaline battery. Therefore, if the number of windings of the separator material is decreased in order to increase the gelled negative electrode mixture, the separator is likely to break due to a decrease in strength of the separator, and an internal short circuit is likely to occur. On the other hand, even if the separator material is wound three or more times to increase the strength of the separator, it is difficult to surely avoid an internal short-circuit, and the discharge performance is deteriorated.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an alkaline battery excellent in impact resistance despite having suitable discharge performance.

Listed below means [1] for solving the above problems.

[1] A bottomed cylindrical positive electrode can, a plurality of positive electrode mixtures in a ring shape fitted along the inner surface of the positive electrode can, and a gelled negative electrode mixture disposed in the center of the positive electrode can An alkaline battery comprising: a separator interposed between the positive electrode mixture and the gelled negative electrode mixture; and a negative electrode current collector configured to include a sealing gasket and sealing the opening of the positive electrode can. The sealing gasket has a boss portion, a plate-like intermediate partition wall formed around the boss portion, and a U-shape bent toward the positive electrode mixture side on the outer peripheral side of the intermediate partition wall portion. And the opening edge on the negative electrode side of the separator is disposed away from the bent portion and in contact with the inner side surface of the intermediate partition wall, and is disposed closest to the opening. Flatten in the direction of the battery center axis at the inner peripheral edge of the opening side end face of the positive electrode mixture. When assuming Do virtual line, its distance from the inner peripheral edge portion along the imaginary line to the sealing gasket is at 1.0 mm or more 2.75mm or less, the separator, vinylon fibers, rayon fibers, polyvinyl alcohol The gelled negative electrode is formed by winding a separator material made of fiber and pulp and having a liquid retention rate of 250% or more and 350% or less twice or more and 5 times or less to a thickness of 230 μm or more and 575 μm or less. An alkaline battery, wherein the amount of zinc powder in the mixture is 2.00 g or more and 3.81 g or less.

As described above in detail, according to the first aspect of the present invention, it is possible to provide an alkaline battery excellent in impact resistance despite having suitable discharge performance.

  Hereinafter, an alkaline battery 11 according to an embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, a positive electrode can 21 constituting the cylindrical alkaline battery 11 (LR6: AA type) of the present embodiment is a bottomed cylindrical battery metal part that also serves as a positive electrode current collector. For example, it is formed by deep drawing press processing of a nickel plating steel plate. In the internal space of the positive electrode can 21, a power generation element (that is, the positive electrode mixture 31, the separator 41, and the gelled negative electrode mixture 51) can be loaded. In the positive electrode can 21, a plurality of positive electrode mixtures 31 formed into a hollow cylindrical shape are vertically stacked and press-fitted concentrically. The positive electrode mixture 31 forming a part of the power generation element is an annular (or tubular) molding mixture containing an oxidizing agent such as manganese dioxide or nickel oxyhydroxide. A bottomed cylindrical separator 41 is inserted inside the positive electrode mixture 31. The separator 41 and the positive electrode mixture 31 are infiltrated with an alkaline electrolyte.

  The hollow portion of the separator 41 is filled with a gelled negative electrode mixture 51 formed by mixing a zinc alloy powder, a gelling agent, an alkaline electrolyte, and the like. In the present embodiment, an aqueous potassium hydroxide solution is used as the alkaline electrolyte. In the present embodiment, zinc alloy powder containing several tens to several hundred ppm of indium, bismuth and aluminum is used. As the gelling agent, for example, carboxymethyl cellulose, polyacrylic acid and its salts, sodium alginate, etherified starch and the like are suitable.

  On the inner surface side of the opening 22 of the positive electrode can 21, a negative electrode current collector 60 formed by assembling a negative electrode terminal plate 61, a negative electrode current collector 71, and a sealing gasket 81 is disposed and crimped. As a result, the positive electrode can 21 is sealed in a liquid-tight manner. An exterior label 23 is attached to the outer surface side of the body portion of the positive electrode can 21.

  The sealing gasket 81 forming a part of the negative electrode current collector 60 has a boss portion 82 at the center, and the negative electrode current collector 71 can be inserted into a boss hole 82a having a circular cross section passing through the boss portion 82. It has become. An intermediate partition wall portion 85 is formed around the boss portion 82, and a peripheral packing portion 83 is formed on the outer periphery of the boss portion 82 via a U-shaped bent portion 84. The sealing gasket 81 is a synthetic resin member having a circular shape in plan view, and is an injection-molded part made of a polyamide resin such as nylon. In place of the polyamide resin, a polyolefin resin such as polypropylene may be used.

  The negative electrode terminal plate 61 that forms part of the negative electrode current collector 60 is made of a conductive metal plate. The negative terminal plate 61 includes a central flat plate portion having a flat terminal surface formed on the outer surface, and an annular recess formed integrally with the outer peripheral portion of the central flat plate portion.

  The negative electrode current collector 71 forming a part of the negative electrode current collector 60 is a bar made of a conductive metal. The tip end side of the negative electrode current collector 71 is inserted into the center of the gelled negative electrode mixture 51 through the opening of the separator 41. On the other hand, the base end portion 72 of the negative electrode current collector 71 is inserted into the boss hole 82a of the boss portion 82 and is fixed to the central portion on the inner surface side of the negative electrode terminal plate 61 by spot welding or the like. In the present embodiment, a tin-plated brass wire is used as a base material constituting the negative electrode current collector 71. The negative electrode current collector 71 of the present embodiment has a circular cross section and an equal cross section (however, a portion excluding the base end portion 72). The tip of the negative electrode current collector 71 in FIG. 1 is not processed into a tapered shape, but of course it may be tapered.

  The negative electrode current collector 60 configured as described above is disposed in the opening 22 of the positive electrode can 21, and the end on the opening 22 side is bent at a right angle toward the radial center together with the peripheral packing portion 83. Has been. As a result, the negative electrode current collector 60 is firmly and liquid-tightly attached to the opening 22 of the positive electrode can 21.

  Here, in the alkaline battery 11 of the present embodiment, the distance L1 (mm) of the predetermined portion, the liquid retention rate (%) of the separator material, the thickness (mm) of the separator 41, and the zinc powder in the gelled negative electrode mixture 51 Is set so that the following preferable conditions are satisfied.

  As shown in FIG. 1, in the alkaline battery 11 of the present embodiment, the opening end on the negative electrode side of the separator 41 is disposed so as to contact the inner surface of the sealing gasket 81. Here, paying attention to the positive electrode mixture 31 arranged closest to the opening 22, an imaginary line S 1 parallel to the direction of the battery center axis C 1 is formed at the inner peripheral edge P 1 of the opening side end face of the positive electrode mixture 31. Suppose. Incidentally, the reason why the “inner peripheral edge P1” is selected as the reference point is that the region of the separator 41 that is in contact with the inner peripheral edge P1 is most likely to break. In this case, the distance L1 (mm) from the inner peripheral edge P1 to the sealing gasket 81 along the virtual line S1 is set to 0 mm or more and 2.75 mm or less. When the distance L1 of this portion exceeds 2.75 mm, the length of the portion surrounded (reinforced) by the positive electrode mixture 31 at the side opening side portion of the separator 41 is reduced, and the opening of the positive electrode mixture 31 is reduced accordingly. The length of the part exposed from the part side end surface will increase. Therefore, the side opening side portion of the separator 41 tends to break. In that respect, if the distance L1 is set within the above range, the side opening side portion of the separator 41 is reinforced, and breakage hardly occurs. However, if the distance L1 is too short, it may cause battery leakage or rupture. More preferably, the distance L1 is 1.0 mm or more and 2.75 mm or less, and more preferably 2.0 mm or more and 2.75 mm. It is better to set the following.

  In the alkaline battery 11 of the present embodiment, the separator 41 is formed using a separator material having a liquid retention rate (%) of 250% to 350%. The separator 41 formed using a separator material having a low liquid retention rate can hardly retain the electrolytic solution when accommodated in the battery, so that the strength can be maintained correspondingly, and breakage hardly occurs. On the other hand, if the liquid retention rate is low, there is a drawback that the discharge performance is lowered. On the other hand, the separator 41 formed using a separator material having a high liquid retention rate is preferable from the viewpoint of improving discharge performance, but cannot maintain a predetermined strength when housed in the battery, and easily breaks. There is a drawback. In that respect, if the liquid retention rate of the separator material is set within a range of 250% or more and 350% or less, both maintenance of discharge performance and maintenance of the strength of the separator 41 can be easily achieved.

  The type of the separator material is not particularly limited and is arbitrary. For example, it is preferable to use a separator material made of vinylon fiber, rayon fiber, polyvinyl alcohol fiber and pulp. This is because the separator material having such a fiber structure is excellent in strength and liquid retention and easily imparts suitable physical properties when the separator 41 is configured.

  Moreover, in the alkaline battery 11 of this embodiment, the separator 41 is formed so that thickness may be 230 micrometers or more and 575 micrometers or less. If the thickness is less than 230 μm, sufficient strength cannot be maintained in the separator 41 and breakage tends to occur. On the other hand, if the thickness is more than 575 μm, the predetermined strength can be maintained, but the mixture filling allowable amount is reduced, so that the discharge performance is deteriorated. In that respect, if the thickness is set within the range of 230 μm or more and 575 μm or less, both of maintaining the discharge performance and maintaining the strength of the separator 41 can be easily achieved.

  Here, the “thickness of the separator 41” means a thickness corresponding to the number of windings of the separator material when the separator 41 is formed by winding the separator material a plurality of times. In addition, it is preferable that the separator 41 is formed by winding a separator material 2 times or more and 5 times or less. When the number of windings is less than 2, breakage is likely to occur due to a decrease in strength of the separator 41, and an internal short circuit is likely to occur. On the other hand, when the number of windings is more than 5, the strength of the separator 41 is increased, but the discharge performance is deteriorated due to the thickening of the separator 41.

  In the alkaline battery 11 of the present embodiment, the amount of zinc powder in the gelled negative electrode mixture 51 is set to 2.00 g or more and 3.81 g or less. When the amount of zinc powder is less than 2.00 g, the amount of the negative electrode active material is reduced, resulting in a deterioration in discharge performance. On the other hand, if the amount of zinc powder is more than 3.81 g, the discharge performance is maintained, but the weight of the gelled negative electrode mixture 51 itself increases and the impact resistance is deteriorated. In that respect, if the amount of zinc powder is set to 2.00 g or more and 3.81 g or less, both maintenance of discharge performance and prevention of reduction in impact resistance can be easily achieved.

  Hereinafter, although the example which actualized the embodiment mentioned above is given and explained, the present invention is not limited to an example.

A. Preparation of evaluation sample and evaluation test method

  Here, some alkaline batteries 11 (LR6) were actually produced and used as samples for evaluation. At that time, the distance L1 (mm), the liquid retention rate of the separator material (%), the thickness of the separator 41 (mm), the number of turns of the separator material (times), the amount of zinc powder in the gelled negative electrode mixture 51 ( g) was set as shown in Table 1.

The zinc dust, apparent specific gravity 2.80 g / cm ³ or more 3.00 g / cm ³ or less, the following particle size distribution 70μm was used as 20% or less.

  In addition, about the Example (namely, Example 1,2,4,5,6,7,9,10) whose liquid retention rate is 320%, vinylon fiber 50%, rayon fiber 15%, polyvinyl alcohol fiber 10% And a separator material made of 25% pulp. For Examples (ie, Examples 3 and 8) having a liquid retention rate other than 320%, the same fiber composition as that described above was used, but the content ratio was slightly changed.

  For the conventional example having a liquid retention rate of 411%, a separator material made of acetalized vinylon fiber, cellulose, and vinylon binder fiber was used.

  For Comparative Example 2 with a liquid retention rate of 360%, a separator material made of acetalized vinylon fiber, mercerized wood pulp, and vinylon binder fiber was used. About the comparative example whose liquid retention is 320% or 240%, the separator material which consists of vinylon fiber, rayon fiber, polyvinyl alcohol fiber, and a pulp was used.

In this example, a drop test was performed under the conditions shown in FIG. 2 as an evaluation test for each sample for evaluation. First, two alkaline batteries 11 as evaluation samples are arranged in series and fixed with a tape 91, which is arranged directly above a 30 mm square piece of wood 92 with the negative electrode side facing downward. Then, the evaluation sample in this state was freely dropped vertically from a height of 1.5 m and collided with the wooden piece 92 ten times. Thereafter, the inside of each sample for evaluation was observed, and the number of those in which an internal short circuit occurred was counted (n = 30). The results are also shown in Table 1. Incidentally, FIG. 3 shows the alkaline battery 11 in a state where the gelled negative electrode mixture 51 has largely moved to the negative electrode side as a result of the impact caused by dropping.
B. Results of evaluation test

  As is apparent from the results shown in Table 1, in the conventional example, the internal short-circuit occurrence rate was considerably high (24/30). In each of Comparative Examples 1 to 5, an internal short circuit occurred, and particularly in Comparative Examples 1 and 5, this was remarkable. In Comparative Example 6, no internal short circuit occurred, but satisfactory discharge performance could not be obtained.

  On the other hand, in each Example, despite having satisfactory discharge performance at the same level as the conventional product, no internal short circuit occurred, and it had excellent impact resistance. .

  As described above in detail, according to the alkaline battery 11 of the present embodiment, it is possible to provide the alkaline battery 11 excellent in impact resistance despite having suitable discharge performance. Therefore, for example, even when a very large impact is applied when used in a controller such as a game machine, it is possible to prevent the occurrence of an internal short circuit and avoid the heat generation of the battery.

  In addition, you may change embodiment of this invention as follows.

  In the above embodiment, the sealing gasket 81 having a shape as shown in FIG. 1 or the like is used, but a simple sealing gasket having no bent portion 84 may be used, for example. In the present embodiment, the negative electrode current collector 60 is configured by using the negative electrode terminal plate 61, the negative electrode current collector 71, and the sealing gasket 81. However, the negative electrode current collector 60 is further added by adding a member such as an insulating washer. It may be configured.

  In the above embodiment, one separator 41 is formed by winding one separator material a plurality of times. However, the present invention is not limited to this. For example, two separators are arranged in a cross and pasted on each other. One separator may be formed by forming into a cylindrical shape.

The sectional view showing the alkaline battery of one embodiment which materialized the present invention. Schematic for demonstrating the method of the drop test performed in embodiment. Sectional drawing which shows the alkaline battery of the state to which the impact by dropping was added.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Alkaline battery 21 ... Positive electrode can 22 ... Opening part 31 ... Positive electrode mixture 41 ... Separator 51 ... Gel-like negative electrode mixture 60 ... Negative electrode collector 81 ... Sealing gasket C1 ... Battery center axis L1 ... Distance P1 ... Opening side Inner peripheral edge of end face S1 ... Virtual line

Claims (1)

A bottomed cylindrical positive electrode can, a plurality of positive electrode mixtures in a ring shape fitted along the inner surface of the positive electrode can, a gel-like negative electrode mixture disposed in the center of the positive electrode can, In an alkaline battery comprising a separator interposed between a positive electrode mixture and the gelled negative electrode mixture, and a negative electrode current collector configured to include a sealing gasket and sealing an opening of the positive electrode can,
The sealing gasket is formed such that a boss portion, a plate-shaped intermediate partition wall formed around the boss portion, and a U-shape bent toward the positive electrode mixture side on the outer peripheral side of the intermediate partition wall portion. A bent portion,
An opening edge on the negative electrode side of the separator is disposed apart from the bent portion and in contact with the inner surface of the intermediate partition wall,
When an imaginary line parallel to the battery center axis direction is assumed at the inner peripheral edge of the opening-side end surface of the positive electrode mixture disposed closest to the opening, the sealing gasket extends from the inner peripheral edge along the imaginary line. The distance is 1.0 mm or more and 2.75 mm or less,
The separator is made of vinylon fiber, rayon fiber, polyvinyl alcohol fiber and pulp , and a thickness of 230 μm or more and 575 μm by winding a separator material having a liquid retention rate of 250% or more and 350% or less 2 times or less. Formed to be:
The alkaline battery, wherein the amount of zinc powder in the gelled negative electrode mixture is 2.00 g or more and 3.81 g or less.

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