JP2003045399A - Separator and alkali cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkali cell enabled to restrain the increase of separator film resistance at discharge. SOLUTION: The alkali cell 1 comprises a positive electrode 3, a negative electrode 5, and a separator 4. The separator 4 has a structure of superposing nonwoven fabrics, and a highly water absorbing polymer is laid between the nonwoven fabrics. The highly water absorbing polymer is composed of crosslinking polyacrilic acid or crosslinked polyacrylate salt, and it is in a state of powder or sheet. The sum of alkali electrolyte liquid absorption volume of the highly water absorbing polymer ranges between 0.4 g and 1.13 g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separator for an alkaline battery and an alkaline battery using this separator.

[0002]

2. Description of the Related Art With the development of portable electronic devices in recent years, there is an increasing demand for a battery as a power source thereof to be able to draw a larger current and be used for a longer period of time. For this reason, how to reduce the internal resistance in the battery will become an important issue.

For example, the reason why the conductive paint is applied to the inside of the can is to improve the adhesion between the positive electrode and the can and to reduce the contact resistance. In addition, a separator that is more likely to move ions and that has good electric conductivity is required. The role of the separator is to separate the positive electrode and the negative electrode so that they do not come into contact with each other, have excellent electrolyte retention and have good ionic conductivity and low electrical resistance, and be stable with respect to the electrolytic solution. May have low impurity levels and high productivity.

Among these, the fibers constituting the separator have been conventionally used because of their excellent liquid-retaining property for electrolyte, good ion conductivity, low electric resistance and stability for electrolyte. The nylon type has been changed from polypropylene (PP), polyethylene (PE), and vinylon, which are more alkaline resistant, and the blending ratio is hydrophilic in order to increase the liquid retention amount and lower the electrical resistance. The method of increasing the blending ratio of rayon fiber and pulp fiber has been adopted.

[0005]

However, generally, in an alkaline battery, volume expansion occurs in the discharge reaction of both or one of the positive electrode and the negative electrode, so that the separator is pressed and the held electrolytic solution is released. For this reason, the amount of the electrolytic solution retained inside the separator is reduced and mass transfer becomes difficult, which causes a problem of increasing the internal resistance of the battery.

The present invention has been made in view of the above problems, and an object thereof is to provide a separator capable of suppressing an increase in the membrane resistance of the separator during discharging, and an alkaline battery using this separator. To do.

[0007]

Means for Solving the Problems The separator of the present invention is
A separator having a structure in which non-woven fabrics are stacked and having a superabsorbent polymer between the stacked non-woven fabrics, and having the separator, and an alkaline battery including a positive electrode, a negative electrode, and an alkaline electrolyte, are excellent. Achieves excellent battery performance.

Here, the above-mentioned superabsorbent polymer is preferably composed of a crosslinked polyacrylic acid or a crosslinked polyacrylic acid salt, and the crosslinked polyacrylic acid salt is more preferably a sodium salt. The superabsorbent polymer described above is more preferably made of powder or in the form of a sheet, and the total absorbed amount of the alkaline electrolyte in the superabsorbent polymer is in the range of 0.4 to 1.13 g. More preferable.

The alkaline battery of the present invention is an alkaline battery comprising a positive electrode, a negative electrode, and a separator,
The separator has a structure in which non-woven fabrics are superposed, and the super absorbent polymer is provided between the superposed non-woven fabrics.

The above-mentioned superabsorbent polymer is preferably composed of crosslinked polyacrylic acid or crosslinked polyacrylic acid salt, and the crosslinked polyacrylic acid salt is more preferably sodium salt. The superabsorbent polymer described above is more preferably made of powder or in the form of a sheet, and the total absorbed amount of the alkaline electrolyte in the superabsorbent polymer is in the range of 0.4 to 1.13 g. More preferable.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the invention relating to a separator and an alkaline battery will be described below.

First, the separator according to this embodiment will be described. This separator has a structure in which non-woven fabrics are superposed, and a super absorbent polymer is placed between the superposed non-woven fabrics.

Here, the super absorbent polymer will be described. First, the material of the superabsorbent polymer will be described.
The material of the superabsorbent polymer is preferably crosslinked polyacrylic acid or crosslinked polyacrylate. Further, the cross-linked polyacrylic acid salt is preferably a sodium salt. The term "crosslinked" means that the polymer has a three-dimensional network structure due to crosslinking.

The material of the superabsorbent polymer is not limited to the above-mentioned crosslinked polyacrylic acid or crosslinked polyacrylic acid salt. The material of super absorbent polymer is
It is possible to employ one that is excellent in retaining the electrolyte, has good ionic conductivity, has low electric resistance, and is stable to the alkaline electrolyte. Specifically, polymers such as starch-graft copolymer type, polyvinyl alcohol type, polyvinyl alcohol-polyacrylic acid type, polyacrylamide type, isobutylene-maleic acid copolymer, cellulose type and polyether type should be adopted. You can

Further, the cross-linked polyacrylic acid salt is not limited to the above-mentioned sodium salt. As the cross-linked polyacrylic acid salt, potassium salt, lithium salt and the like can be adopted.

Next, the shape of the super absorbent polymer will be described. The shape of the super absorbent polymer is preferably a powder. The reason is that the area of contact with the electrolytic solution becomes large and the liquid absorption speed increases.

Here, the average particle size of the powder is 10 to 60 μm.
It is desirable to be in the range of. This is because if the particle size is too small, the liquid absorbing ability is low and the effect is low, and if it is too large, the liquid absorbing amount becomes too large and the amount of electrolyte required in the battery decreases.

The shape of the super absorbent polymer is preferably a sheet. The reason is that the shape is stable when the electrolyte solution is absorbed, and the localization of the electrolyte solution can be prevented.

Here, the thickness of the sheet is 15 to 150 μm.
It is desirable to be in the range of. This is because when the thickness of the sheet is within this range, there is an advantage that a sufficient liquid absorbing tissue can be knitted.

The shape of the super absorbent polymer is not limited to the above powder or sheet shape. In addition to this, a cylindrical shape or the like can be adopted as the shape of the superabsorbent polymer.

Next, it is desirable that the amount of the superabsorbent polymer absorbed by the alkaline electrolyte is in the range of 10 to 40 g / g. If too much liquid is absorbed, the electrolyte in the battery will run short,
Also, if the liquid absorption amount is small, the effect is lost. The absorbed amount of the alkaline electrolyte is the maximum mass of the electrolyte that can be absorbed by the superabsorbent polymer having a unit mass.

Next, the total absorbed amount of the alkaline electrolyte of the superabsorbent polymer is preferably in the range of 0.4 to 1.13 g, and more preferably in the range of 0.51 to 1.13 g. When the total amount of the alkaline electrolyte absorbed is within this range, there is an advantage that the required amount of electrolyte can be secured against the demand of external load, and the increase in the membrane resistance of the separator can be prevented. is there.

The total absorbed amount of the alkaline electrolyte is defined as follows. That is, the product XY of both is the total amount of the alkaline electrolyte absorbed when the amount of the alkaline electrolyte absorbed by the superabsorbent polymer is Xg / g and the amount of the added superabsorbent polymer is Yg.

Next, the structure of the material of the separator will be described. The texture of the material of the separator is preferably made of non-woven fabric. The reason is that the pore size is large and the super-absorbent polymer easily enters.

The structure of the material of the separator is not limited to the above-mentioned nonwoven fabric. For the structure of the material of the separator, a microporous film or the like can be adopted.

Next, the structure of the separator will be described. The structure of the separator is preferably a structure in which nonwoven fabrics are stacked. Examples of the structure in which the nonwoven fabrics are stacked are as follows.

Take the first example. Considering a cylinder that is the final shape of the separator, prepare two strip-shaped nonwoven fabrics having a width slightly longer than half the length of the outer circumference of the cylinder,
Cross these in a cross shape. Using a jig,
It is shaped like a cylinder with a bottom (hereinafter referred to as "cross-shaped separator"). This makes it possible to obtain a separator having a double structure.

In the next example, a rectangular non-woven fabric is double wound to form a cylinder, and then one end of the cylinder is bent to form a bottom (hereinafter referred to as a "double-wrap structure separator").

In the next example, a strip-shaped nonwoven fabric is obliquely wound to form a cylinder. In this case, it is necessary to wind up the non-woven fabric one cycle before and the non-woven fabric to be overlapped with it so that at least half of the width of the strip overlaps. As a result, a spirally wound cylinder is obtained. After cutting this to a certain length, bend one end of the cylinder to form the bottom (hereinafter,
It is called "spiral wound separator". )

The structure of the separator is not limited to the above-mentioned cross structure, double winding structure, or spiral winding structure. In addition to this, the separator may have a folded or folded structure.

Next, the material of the non-woven fabric will be described.
As the material of the non-woven fabric, vinylon, rayon or the like can be adopted. However, the material of the nonwoven fabric is not limited to these vinylon and rayon. In addition, as the material of the non-woven fabric, polyamide, vinyl chloride-
Acrylonitrile copolymer, polyolefin (for example,
Synthetic fibers such as polyethylene and polypropylene), natural fibers, glass fibers and the like can be adopted.

As described above, the separator has a structure in which nonwoven fabrics are stacked. A super absorbent polymer is arranged between the superposed nonwoven fabrics. Here, a method of arranging the super absorbent polymer and a region where the super absorbent polymer is arranged will be described.

First, the case where the super absorbent polymer is a powder will be described. When the super absorbent polymer is a powder, the powder is rubbed on the surface of the non-woven fabric.
By rubbing in, the powder can be prevented from falling from the nonwoven fabric due to gravity. However, the arrangement method is not limited to this rubbing method. In addition to this, there is a method of arranging a method in which powder is filled between the non-woven fabrics, then integrated treatment is performed, and processed into a sheet.

Next, of the surface area of the separator, the area where the powder is placed will be described. First, the cross-shaped separator will be described. In this case, the powder is placed inside the strip-shaped non-woven fabrics that are stacked in a cross shape. That is,
Place it on the lower side of the upper strip of the two strips, on the upper side of the lower strip, or on the lower side of the upper strip and the upper side of the lower strip. Place on both sides.

Next, a separator having a double winding structure will be described. In this case, the powder is arranged on one of the surfaces of the rectangular non-woven fabric which is approximately half the width in the winding direction, or the powder is arranged on the back surface corresponding to the region where the powder is not arranged. The non-woven fabric is wound so that the powder comes inside.

Next, the spirally wound separator will be described. In this case, the powder is placed on approximately one half of the width direction of one side of the strip-shaped nonwoven fabric, or the powder is placed on the back surface corresponding to the area where the powder is not placed.
The strip-shaped nonwoven fabric is wound so that the powder enters inside.

As described above, the region where the superabsorbent polymer is arranged is the region where the nonwoven fabrics overlap. Therefore, even if the separator has a structure other than the cross structure, the double winding structure, and the spiral winding structure, it is desirable to dispose the powder while the nonwoven fabrics are overlapped. However, in the final product of the separator, the powder need not be arranged in the entire area of the bottomed cylinder. The effect of the present invention can be obtained even when the powder is arranged in some regions.

Next, a method of arranging the sheet and a region where the sheet is arranged when the super absorbent polymer is a sheet will be described.

When the super absorbent polymer is a sheet,
Examples of the disposing method include a method in which the nonwoven fabric and the sheet are subjected to a primary treatment (for example, pressure, heat treatment, etc.) to be integrated, or a method in which the nonwoven fabric surface and the sheet surface are chemically bonded.

Next, of the surface area of the separator, the area where the sheet is arranged will be described. The area for arranging the sheet is the same as the area for arranging the above-mentioned powder. Further, even if the separator has a structure other than a cross structure, a double winding structure, and a spiral winding structure, it is desirable to arrange the sheets while the nonwoven fabrics are overlapped.

However, when the super absorbent polymer is a sheet, the non-woven fabrics do not necessarily have a structure in which they overlap. That is, most of the area of the separator is a single piece of non-woven fabric, and the non-woven fabric may carry a sheet.

Further, in the final product of the separator, the sheet need not be arranged in the entire area of the bottomed cylinder.
It may be a case where the sheet is arranged in a part of the area.

It is needless to say that the present invention is not limited to the above-mentioned embodiment and can take various other configurations without departing from the gist of the present invention.

As described above, according to the present embodiment, when a proper amount of the super absorbent polymer is arranged between the nonwoven fabrics of the separator, the super absorbent polymer can absorb and retain the electrolytic solution. Since this superabsorbent polymer has a high ability to retain the electrolytic solution with respect to pressure, it retains the electrolytic solution even after external pressure is applied. Therefore, the increase in the membrane resistance of the separator can be suppressed.

Next, the alkaline battery according to this embodiment will be described. FIG. 1 is a cross-sectional view showing an alkaline manganese battery as a configuration example of the alkaline battery according to the present embodiment. That is, this battery 1 is a battery having a positive electrode using manganese dioxide as a positive electrode active material and a negative electrode using zinc as a negative electrode active material.

Specifically, the battery 1 includes a battery can 2 and
A positive electrode 3, a separator 4, a negative electrode 5, a sealing member 6,
The washer 7, the negative electrode terminal plate 8, and the collector pin 9 are provided.

Here, the battery can 2 is a bottomed cylindrical metal can having an opening. The battery can 2 is, for example, iron plated with nickel and serves as an external positive electrode terminal of the battery.

The positive electrode 3 has a hollow cylindrical shape, and contains a positive electrode mixture composed of manganese dioxide, which is a positive electrode active material, graphite powder, which is a conductive agent, and potassium hydroxide aqueous solution, which is an electrolytic solution. Formed into positive electrode pellets 3a, 3b,
3 c is laminated inside the battery can 2.

The separator 4 is in the shape of a cylinder having a small wall thickness, one end is closed, and the other end has an opening. The separator 4 is arranged so as to contact the inside of the positive electrode 3. The specific content of the separator 4 is as described in the embodiment of the invention regarding the separator.

The negative electrode 5 includes zinc powder as a negative electrode active material,
It is composed of an electrolytic solution using an aqueous solution of potassium hydroxide, a zinc powder and a thickener for uniformly dispersing the electrolytic solution in a gel form of the negative electrode 5. The negative electrode 5 is injected inside the bottomed cylindrical separator 4.

The opening of the battery can 2 in which the positive electrode 3 and the separator 4 filled with the negative electrode 5 are housed is
A sealing member 6 is fitted to seal this opening. The sealing member 6 is made of a plastic material, and a washer 7 and a negative electrode terminal plate 8 are attached so as to cover the sealing member 6.

Further, a brass current collecting pin 9 is press-fitted into the through hole of the sealing member 6 to which the washer 7 is attached from above. Thereby, the current collection of the negative electrode is ensured by the nail-shaped current collection pin 9 welded to the negative electrode terminal plate 8 being pressed into the through hole formed in the central portion of the sealing member 6 and reaching the negative electrode. There is. The positive electrode current collection is ensured by connecting the positive electrode 3 and the battery can 2. The outer peripheral surface of the battery can 2 is covered with an exterior label (not shown), and the positive electrode terminal is located below the battery can 2.

Although the alkaline manganese battery has been described in the present embodiment, the present invention can be applied to the same alkaline battery system such as nickel cadmium battery, air zinc battery, nickel zinc battery, nickel hydrogen battery and silver oxide battery. .

In the present embodiment, the alkaline manganese battery which is the primary battery has been described, but the present invention is not limited to this primary battery, and the present invention can be applied to other secondary batteries.

In the present embodiment, the cylindrical alkaline manganese battery has been described, but the present invention is not limited to this cylindrical battery, and the present invention can be applied to batteries having other shapes such as a flat battery. Of course, it can be applied. Moreover, the battery size is not particularly limited.

Further, the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

As described above, according to the present embodiment, since the separator in which an appropriate amount of super absorbent polymer is arranged between the non-woven fabrics, the super absorbent polymer can absorb and retain the electrolytic solution. Since this superabsorbent polymer has a high ability to retain the electrolytic solution with respect to pressure, it retains the electrolytic solution even after external pressure is applied. Therefore, the increase in the membrane resistance of the separator can be suppressed. From this, it is possible to extend the discharge time under heavy load by suppressing the increase in the internal resistance of the battery during and after the discharge. That is, it is possible to provide an alkaline battery having excellent heavy load discharge characteristics.

[0058]

EXAMPLES Next, examples of the present invention will be specifically described. However, it goes without saying that the present invention is not limited to these examples.

First, a method for producing a battery sample will be described for the conventional example, Examples 1 to 4 and Comparative Examples 1 to 3.

[Conventional Example] As shown in FIG. 1, the battery of the conventional example has a lower end portion closed and a cylindrical battery can 2 having an opening portion at the upper end portion thereof. A positive electrode 3 is provided in which a plurality of positive electrode pellets formed by molding a positive electrode mixture made of a potassium aqueous solution (40% by mass) into a hollow cylinder are stacked. Vinylon inside the positive electrode 3,
A gelled negative electrode 5 composed of granular zinc, an aqueous potassium hydroxide solution (40% by mass), a thickener, etc. is built in via a nonwoven fabric separator 4 made of rayon. In addition,
As the separator, a cross-shaped separator was produced.

The outer peripheral surface of the cylinder of the battery can 2 is covered with an outer label, and the positive electrode terminal is located below the battery can 2. A sealing body is fitted in the opening of the battery can 2. The sealing body comprises a negative electrode terminal plate 8, a sealing member 6, and a washer 7. The sealing member 6 is made of a plastic material, and the washer 7 and the negative electrode terminal plate 8 are attached so as to cover the sealing member 6. Further, a brass current collecting pin 9 is press-fitted into the through hole of the sealing member 6 into which the reinforcing member is fitted from above. In this way, a sample of AA alkaline manganese battery is completed.

Example 1 The battery of Example 1 was manufactured by the same method as the conventional example. However, a super absorbent polymer (crosslinked sodium polyacrylate, apparent density 0.7 g / ml, alkaline electrolyte solution absorption amount 30 g / g, particle size width 20 to 50 μm) was added between the nonwoven fabrics of the separator. Here, the total absorbed amount of the alkaline electrolyte is 0.4 g.

Example 2 The battery of Example 2 was manufactured by the same method as in Example 1. Here, the total absorbed amount of the alkaline electrolyte is 0.51 g. [Example 3] The battery of Example 3 was manufactured in the same manner as in Example 1. Here, the total absorbed amount of the alkaline electrolyte is 1.
It is 13 g.

Example 4 The battery of Example 4 was manufactured in the same manner as in Example 1. However, the super absorbent polymer added between the non-woven fabrics is composed of cross-linked polyacrylic acid, has an apparent density of 0.2 g / ml, an alkaline electrolyte absorption amount of 40 g / g, and a particle size width of 10 to 30 μm. . Here, the total absorbed amount of the alkaline electrolyte is 0.81 g.

Comparative Example 1 The battery of Comparative Example 1 used the same manufacturing method as in Example 1. Here, the total absorbed amount of the alkaline electrolyte is 1.3 g.

Comparative Example 2 The battery of Comparative Example 2 used the same manufacturing method as in Example 1. However, the super absorbent polymer added between the non-woven fabrics is composed of a linear polyacrylic acid gelling agent and has an apparent density of 0.2 g / ml and a particle size width of 1
~ 5 μm. Here, the total absorbed amount of the alkaline electrolyte is 0.51 g.

Comparative Example 3 The battery of Comparative Example 3 used the same manufacturing method as in Comparative Example 2. Here, the total liquid absorption of the alkaline electrolyte is 1.13 g.

Next, the battery samples of the conventional example, Examples 1 to 4 and Comparative Examples 1 to 3 produced as described above were evaluated. Specifically, the evaluation was made by (1) the membrane resistance of the separator after pressure application, and (2) the discharge time in heavy load discharge.

Here, a method for measuring the membrane resistance of the separator after being pressed will be described. First, the final product, a separator, is dipped in a 40% by mass aqueous potassium hydroxide solution for 1 minute. Then, the separator is laid on the paper, a plate (30 mm × 50 mm) is placed on the paper, and a load of 5 kg is applied for 1 minute. Then, from the vertical direction of the thickness of the thinned separator, use an LCR meter to measure the impedance (1 kHz
z) is measured.

Next, a method of measuring the discharge time in heavy load discharge will be described. The battery sample immediately after the production was continuously discharged at 1000 mA and the discharge time was measured. Here, the final voltage of discharge was set to 0.9V.

Conventional Example, Examples 1 to 4, and Comparative Example 1
The evaluation results of the battery sample No. 3 are as shown in Table 1.

[0072]

[Table 1]

From Table 1, Examples 1 to 4 will be examined. Membrane resistance is 1.0 by adding super absorbent polymer
It can be seen that the resistance is about 1.7Ω, which is lower than the film resistance of 2.5Ω in the conventional example. This is because even if the super absorbent polymer retains the electrolytic solution and the separator is compressed and the electrolytic solution in the pores of the separator is released, the electrolytic solution is retained in the super absorbent polymer and the membrane resistance is maintained. This is because that. As a result, the continuous discharge time of 1000 mA was 45 to
It can be seen that the time is 54 minutes, which is longer than the 40 minutes of the conventional example.

From these, it is understood that the membrane resistance of the separator affects the continuous discharge time of 1000 mA. In addition, in Examples 2 to 4, the film resistance was 1.0 to
The value is 1.2Ω and the discharge time is 52 to 54 minutes, which is a particularly excellent value as compared with the film resistance of 2.5Ω and the discharge time 40 minutes in the conventional example. From these facts, the total absorbed amount of the alkaline electrolyte is preferably in the range of 0.4 to 1,13 g, and more preferably in the range of 0.51 to 1.13 g.

On the other hand, as seen in Comparative Example 1, when the amount of the superabsorbent polymer is excessively increased, the membrane resistance of the separator is lowered to 1.1Ω, but the continuous discharge time of 1000 mA is 3
It has decreased to 8 minutes. It is considered that the reason for this is that the electrolyte solution in the battery was absorbed in the separator by excessively increasing the amount of the super absorbent polymer, and the electrolyte solution necessary for the discharge reaction was not supplied to the positive electrode or the negative electrode.

Further, as seen in Comparative Examples 2 and 3, those in which linear polyacrylic acid was used instead of the superabsorbent polymer had a membrane resistance of 2.6 Ω and 2.
It has not dropped to 4Ω. It is considered that this is because the electrolyte solution that had been held was released when pressure was applied because it was not crosslinked.

From the above, according to this example, by adding an appropriate amount of the superabsorbent polymer between the non-woven fabrics having the separators superposed on each other, it is possible to suppress the increase in the membrane resistance when the separators are pressed. it can. As a result, the discharge time of 1000 mA continuous discharge, which is heavy load discharge, can be extended.

[0078]

The present invention has the following effects. Since the separator has a structure in which non-woven fabrics are stacked, and since it has a super absorbent polymer between the stacked non-woven fabrics,
It is possible to suppress an increase in the membrane resistance of the separator during discharging. Further, by using the above separator in an alkaline battery, the discharge time in heavy load discharge can be extended.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the invention relating to a separator and an alkaline battery.

[Explanation of symbols]

1 ... Battery, 2 ... Battery can, 3 ... Positive electrode, 4 ... Separator, 5 ... Negative electrode, 6 ... Sealing member, 7 ... Washer, 8 ... Negative electrode terminal plate, 9 ... Current collecting pin

Claims (12)

[Claims] 1. A separator for an alkaline battery having a structure in which non-woven fabrics are stacked, wherein the super-absorbent polymer is provided between the stacked non-woven fabrics. 2. The separator according to claim 1, wherein the super absorbent polymer is made of crosslinked polyacrylic acid or crosslinked polyacrylic acid salt. 3. The separator according to claim 2, wherein the crosslinked polyacrylic acid salt is a sodium salt. 4. The separator according to claim 2, wherein the superabsorbent polymer is made of powder. 5. The separator according to claim 2, wherein the super absorbent polymer has a sheet shape. 6. The separator according to claim 4, wherein the superabsorbent polymer has a total absorbed amount of alkaline electrolyte of 0.4 to
It is characterized by being in the range of 1.13 g. 7. An alkaline battery provided with a positive electrode, a negative electrode, and a separator, wherein the separator has a structure in which nonwoven fabrics are stacked, and a super absorbent polymer is provided between the stacked nonwoven fabrics. 8. The alkaline battery according to claim 7, wherein
The superabsorbent polymer is characterized by comprising a crosslinked polyacrylic acid or a crosslinked polyacrylic acid salt. 9. The alkaline battery according to claim 8, wherein
The cross-linked polyacrylic acid salt is characterized by being a sodium salt. 10. The alkaline battery according to claim 8, wherein the superabsorbent polymer is made of powder. 11. The alkaline battery according to claim 8, wherein the superabsorbent polymer is in a sheet form. 12. The alkaline battery according to claim 10, wherein the total absorbed amount of the alkaline electrolyte of the highly water-absorbent polymer is in the range of 0.4 to 1.13 g.