JPH08315831A - Manganese dry battery - Google Patents

Abstract

PURPOSE: To provide a manganese dry battery to which no mercury is added with no sharp drop in discharge performance even in low rate discharge by using a neutral electrolyte containing a silicon-containing, water-soluble polymer in the manganese dry battery in which non-amalgamated zinc is used in a negative electrode active material. CONSTITUTION: In a manganese dry battery using non-amalgamated zinc in a negative electrode active material, a neutral electrolyte containing a silicon- containing, water-soluble polymer in an electrolyte whose main component is zinc chloride or ammonium chloride is used. The silicon-containing, water-soluble polymer has a chemical formula represented by the formula, and the content in the electrolyte is 0.0005-0.5wt%, preferably 0.005-0.01wt%. Low rate discharge performance equal to that of a manganese dry battery using amalgamated zinc is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a manganese dry battery using mercury-free zinc as a negative electrode active material.

[0002]

2. Description of the Related Art Conventionally, a manganese dry battery has been used with its surface being roughened to prevent self-depletion of zinc used as a negative electrode active material. However, in recent years, when environmental protection has been sought, manganese dry batteries that do not use mercury for this purpose have been developed, and most of the cylindrical manganese dry batteries that are currently produced and sold in Japan have no added mercury.

[0003]

However, when a manganese dry battery is constructed by using an unblended negative electrode can as a negative electrode material, the discharge performance may be drastically lowered by a certain load resistance.

This phenomenon is likely to occur during light load discharge, and as a result of investigating the inside of the battery in which this phenomenon occurred, it was found that an internal short circuit was caused by the discharge reaction product.

This is because when discharged at a specific current, zinc is selectively eluted at a limited part of the zinc surface, and needle-like crystals of a zinc compound are generated at that part, and the crystals are separated by a separator. It is presumed that it may penetrate through and come into contact with the positive electrode mixture, resulting in a short circuit phenomenon.

Therefore, as a countermeasure against this, it is easily conceivable to thicken the material of the separator, increase the beating degree of the kraft paper as the separator material to increase the density, or thicken the glue layer of the separator. If such a method is taken, the distance between the electrodes is increased and the internal resistance of the battery is increased, which significantly reduces the discharge performance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a mercury-free manganese dry battery that does not cause a rapid decrease in discharge performance even under light load discharge.

[0008]

In order to achieve this object, a manganese dry battery using mercury-free zinc according to the present invention uses zinc chloride or ammonium chloride by using undenatured zinc as a negative electrode active material. A neutral electrolytic solution containing a silicon-containing water-soluble polymer is used in the electrolytic solution containing as a main component.

In this case, the content of the silicon-containing water-soluble polymer in the electrolytic solution is 0.0005 to 105 as the content of silicon.
The range of 0.5% by weight is preferable, and 0.005 to 0.01
A range of weight% is more preferable.

In addition, the mercury-free dry battery of the present invention uses unhydrogenated zinc as the negative electrode active material, and contains a silicon-containing water-soluble polymer in the sizing material of the sizing layer of the separator having a sizing layer on the surface. It is characterized by using a separator.

In this case, the content of the silicon-containing water-soluble polymer in the paste is 0.0005-0.5 as the content of silicon.
The range of 0.5% by weight is preferable, and 0.005 to 0.01
A range of weight% is more preferable.

The silicon-containing water-soluble polymer is not particularly limited as long as silicon is chemically bonded to the hydrophilic polymer. For example, the following chemical formula I

[0013]

Embedded image

Those represented by are preferred.

[0015]

By adding such a silicon-containing water-soluble polymer to the battery, the deterioration of discharge performance at a specific load resistance is no longer observed. Although the action against this fact is not clear, it is considered that the presence of the silicon-containing water-soluble polymer suppressed the short circuit between the positive electrode active material and the negative electrode active material.
It is presumed that this is because the needle-like crystals of the zinc compound generated by the discharge are suppressed and the internal short-circuit phenomenon due to the penetration of the separator portion is eliminated.

[0016]

EXAMPLES An example of the present invention will be described below.

In a neutral electrolytic solution consisting of 30% by weight of zinc chloride, 1.5% by weight of ammonium chloride and 68.5% by weight of water, the silicon content shown in (Table 1) was used for the amount of this electrolytic solution. The polyvinyl silicon-containing polymer represented by the chemical formula I (R-2105 manufactured by Kuraray Co., Ltd.) was added and stirred,
It was adjusted. Using this electrolyte, a R20 size mercury-free manganese dry battery shown in FIG. 1 was constructed.

Further, in a manganese battery separator paste liquid comprising 45% by weight of cross-linked etherified corn starch as a gelatinizing agent, 2% by weight of polyvinyl alcohol as a binder and 53% by weight of water, the paste ( The polyvinyl silicon-containing polymer (R-2105 manufactured by Kuraray Co., Ltd.) was added in an amount shown in Table 1), and the mixture was stirred and adjusted.
The R20 size mercury-free manganese dry battery shown in FIG. 1 was constructed using the dry battery separator in which this paste was applied to one side of the separator kraft paper and dried to form a paste layer.

[0019]

[Table 1]

In FIG. 1, 1 is a positive electrode mixture, 2 is a separator having a glue layer on one side, 3 is a negative electrode zinc can, 4 is bottom insulating paper, 5 is a carbon rod as a positive electrode current collector, and 6 is a positive electrode. Is a cap integrated sealing plate, 7 is a bottom plate serving as a negative electrode terminal, and 8 is an outer can.

The positive electrode mixture 1 used at this time was a mixture of manganese dioxide and acetylene black in a mixing weight ratio of 7: 1 to which 40% by weight of the electrolytic solution was added to the solid content.

In Comparative Example 1, as an electrolyte solution which has been generally used in the past, zinc chloride of 30% by weight, ammonium chloride of 1.5% by weight and water of 68.5% by weight were used and gelatinized. Cross-linked etherified cornstarch 4 as an agent
5% by weight, 2% by weight of polyvinyl alcohol as a binder and 53% by weight of water are used as a separator solution for a manganese dry battery, a separator made of kraft paper which is coated on one side and dried, and a negative electrode zinc can. Was used to construct a conventional paper-lined mercury-free manganese dry battery.

Further, as Comparative Example 2, the same as Comparative Example 1 except that a paste obtained by adding 2% by weight of sweet syrup to a sizing agent was applied to the above manganese dry battery separator sizing liquid and dried. Then, a manganese dry battery was constructed.

The results of the continuous discharge test under a load of 50 kΩ and the continuous discharge test under a load of 2 Ω for these manganese dry batteries are shown in Table 2.

The discharge curve of the 50 kΩ continuous discharge test is shown in FIG. In the figure, A is a normal discharge curve, and B is a discharge curve of a battery in which a sudden voltage drop occurred during discharging.

In the 50 kΩ load continuous discharge test, each n = 50
And the number x of batteries in which the voltage drastically dropped during discharge at that time was displayed in the form of x / 50.

A 2Ω load continuous discharge test was conducted at each n = 10, and the average discharge duration (minutes) until the battery voltage during discharge reached 0.9V was shown.

[0028]

[Table 2]

As can be seen from these results, the presence of the polyvinyl silicon-containing polymer in the electrolytic solution or the separator paste has the effect of suppressing a sharp drop in discharge performance during light load discharge.

The amount of addition is 0.0 in terms of silicon content.
When it is 005% by weight or more, the suppression effect becomes remarkable, and 0.00
It can be seen that the suppression effect is further increased at 5% by weight or more.

When the amount added exceeds 1.0% by weight, the suppressing effect is recognized, but on the other hand, the 2Ω continuous discharge performance is deteriorated. Therefore, the addition amount of this polyvinyl-based silicon-containing polymer is 0.01% by weight, which prevents the deterioration of the discharge performance under a light load and has a smaller decrease in the 2Ω continuous discharge performance.
The following additions are desirable.

In the above examples, R-2105 manufactured by Kuraray Co., Ltd., which is represented by the chemical formula I, was used. However, other polyvinyl-based silicon-containing polymers, methylcellulose-based, carboxymethylcellulose-based, and polyoxyethylene-based silicon-containing polymers were used. Almost the same effect was obtained with the polymer.

Further, in the above-mentioned embodiment, the neutral electrolyte mainly containing zinc chloride was used, but the same effect was obtained even when the electrolyte mainly containing ammonium chloride was used.

[0034]

As described above, according to the present invention, in a manganese dry battery using unhydrogenated zinc as a negative electrode active material, a conventional hydrous zinc is added by adding a silicon-containing water-soluble polymer into the battery. It is possible to obtain light load discharge performance equivalent to that of the manganese dry battery used.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cylindrical manganese dry battery according to the present invention.

FIG. 2 is a diagram showing a 50 KΩ load continuous discharge curve showing the effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode mixture 2 Separator 3 Negative zinc can 4 Bottom insulating paper 5 Carbon rod 6 Cap integrated sealing plate 7 Negative electrode terminal bottom plate 8 Exterior can

Claims (7)

[Claims] 1. A manganese dry battery using unrestricted zinc as a negative electrode active material, wherein a neutral electrolytic solution containing a silicon-containing water-soluble polymer is added to an electrolytic solution containing zinc chloride or ammonium chloride as a main component. A manganese dry battery characterized by being used. 2. The manganese dry battery according to claim 1, wherein the content of the silicon-containing water-soluble polymer in the electrolytic solution is 0.0005 to 0.5% by weight as the content of silicon. 3. The manganese dry battery according to claim 1, wherein the content of the silicon-containing water-soluble polymer in the electrolytic solution is 0.005 to 0.01% by weight as the content of silicon. 4. A manganese dry battery in which unnegative zinc is used as a negative electrode active material, and a silicon-containing water-soluble polymer is contained in the paste material of the glue layer of a separator having a glue layer on the surface. Manganese dry battery characterized by. 5. The content of the silicon-containing water-soluble polymer in the paste is 0.0005 to 0.5% by weight as the content of silicon.
The manganese dry battery according to claim 4, which is 6. The content of the silicon-containing water-soluble polymer in the paste is 0.005-0.01% by weight as the content of silicon.
The manganese dry battery according to claim 4, which is 7. The silicon-containing water-soluble polymer has the following chemical formula I: The manganese dry battery according to any one of claims 1 to 6, which is represented by: