JP2000223113A - Zinc alkaline battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily fill a gelatinous zinc negative electrode in a battery and also improve impact resistance and discharge performance in a low-pollution zinc alkaline battery using non-amalgamated zinc alloy powder for a gelatinous zinc negative electrode. SOLUTION: This zinc alkaline battery allows reducing pollution to the environment by use of non-amalgamated zinc alloy powder for a gelatinous zinc negative electrode 4. Chain polyacrylic acid or chain sodium polyacrylate is added by 0.05-0.5 wt.% to an alkaline electrolytic solution in the gelatinous zinc negative electrode 4 having a viscosity of 100,000-300,000 cp at 25 deg.C. Thereby, a filling property of the gelatinous zinc negative electrode 4 and impact resistance of the battery can be improved, and discharge performance can be kept high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zinc-alkaline battery, and more particularly, to a zinc-alkaline battery provided with a gelled zinc negative electrode using a non-melted zinc alloy powder.

[0002]

2. Description of the Related Art Conventionally, as a negative electrode active material for a zinc alkaline battery, a zinc alloy powder of mercurized zinc alloy has been used for the purpose of suppressing gas generation due to corrosion of zinc and improving electric characteristics. Environmental pollution caused by batteries has become a problem, and low pollution has become a social demand. Zinc alloy compositions to make zinc alloy powders non-melted (mercury-free) and anticorrosives (inhibitors) ), And finally a gelled zinc negative electrode for a mercury-free alkaline battery having practically no problem in gas generation has been developed.

[0003] By the way, it has been found that a battery using only a non-melonized zinc alloy powder has a lower impact resistance than a battery using a non-melonized zinc alloy powder. By reviewing and increasing the amount, measures have been taken to increase the viscosity of the gelled zinc negative electrode to improve the impact resistance.

However, if the viscosity of the gelled zinc negative electrode is increased in order to improve the impact resistance of the battery, the friction with the wall of the filling device when filling the gelled zinc negative electrode increases, and the gelled zinc negative electrode becomes smoother. Since the zinc negative electrode does not flow, a stable filling operation becomes difficult. Therefore, the filling operation is facilitated by adding a fluorine-based surfactant to the gelled zinc negative electrode.

[0005]

However, when a fluorine-based surfactant is added to facilitate gel filling, this acts as an internal resistance of the battery.
There has been a problem that the discharge duration is short.

The present invention has been made in view of the above circumstances, and has as its object to provide a low-pollution zinc-alkali battery using a non-melting zinc alloy powder for the gelled zinc negative electrode. The present invention is to facilitate the filling of the resin, improve the safety by maintaining good impact resistance, and enhance the discharge performance.

[0007]

That is, the present invention relates to a zinc-alkaline battery using a non-melting zinc alloy powder for a gelled zinc negative electrode and having a viscosity at 25 ° C. of 100,000 to 100%.
A chain polyacrylic acid or a chain sodium polyacrylate is added to a 300,000 cps gelled zinc negative electrode in an amount of 0.05% to 0.5% with respect to an alkaline electrolyte.

In the present invention, the gel zinc anode as described above is used, so that the gel zinc anode can be filled into the battery,
A zinc-alkaline battery excellent in both impact resistance and discharge performance of the battery can be provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention and comparative examples will be described in detail. First, the composition of the non-melonized zinc alloy powder and the alkaline electrolyte was fixed, and the addition amount of the cross-linked sodium polyacrylate as a gelling agent was changed.
The viscosity of the gelled zinc negative electrode at 50,000 ° C.
000,100,000 ± 5,000,200,000
± 5,000,300,000 ± 5,000,350,
5,000 ± 5,000 cps (measured with a B-type viscometer).

Next, based on the gelled zinc negative electrode having these compositions, a linear polyacrylic acid was added to the alkaline electrolyte at 0.0, 0.01, 0.05, 0.1, 0, and 0, respectively. .
Gelled zinc negative electrodes to which 3, 0.5 and 0.7% were added in seven ways were prepared. Using the 35 types of gelled zinc negative electrodes thus obtained, JIS standard LR6 type (AA) shown in FIG.
Shape) Alkaline battery was assembled.

In FIG. 1, reference numeral 1 denotes a bottomed cylindrical metal can also serving as a positive electrode terminal. In the metal can 1, three positive electrode materials 2 formed into a cylindrical shape by pressure are separately filled. . The positive electrode mixture 2 is obtained by mixing a manganese dioxide powder and a carbon powder and pressing the mixture into a hollow cylinder at a predetermined pressure using a molding die. In the hollow portion of the positive electrode mixture 2, a bottomed cylindrical separator 3 made of a nonwoven fabric of acetalized polyvinyl alcohol fiber is disposed. The gelled zinc negative electrode 4 produced by the above method is filled through the separator. In the gelled zinc negative electrode 4, a negative electrode current collector rod 5 made of brass is mounted so that its upper end protrudes from the gelled negative electrode 4. An insulating gasket 6 made of a double annular polyamide resin is disposed on the outer peripheral surface of the projecting portion of the negative electrode current collector rod 5 and the inner peripheral surface of the upper portion of the metal can 1. A ring-shaped metal plate 7 is disposed between the double annular portions of the insulating gasket 6, and a cap-shaped metal sealing plate 8 serving also as a negative electrode terminal is provided on the head of the current collecting rod 5. It is arranged to abut. The inside edge of the metal can 1 is sealed by the gasket 6 and the metal sealing plate 8 by bending the opening edge of the metal can 1 inward. Tables 1 to 3 show the results of investigating the workability, impact resistance, and duration of 1Ω continuous discharge for each of the LR6 alkaline batteries assembled as described above.

[0012]

[Table 1]

Table 1 qualitatively shows the state of workability (flowability on the vessel wall) when the gelled zinc negative electrode is filled. ◎ indicates very good, ○ indicates good, Δ indicates acceptable, and × indicates unacceptable. From Table 1, the viscosity of the gelled zinc negative electrode was 50,000.
It can be understood that addition of linear polyacrylic acid is not necessary for workability in cps. On the other hand, when the viscosity of the gelled zinc negative electrode is 350,000 cps, it is understood that a sufficient effect is not exhibited even when 0.5% of linear polyacrylic acid is added. Also, by adding 0.01% of linear polyacrylic acid,
It was observed that at any viscosity, the effect was almost the same as that of no addition, and the effect began to appear with 0.05% of polyacrylic acid.

The workability is improved by the addition of the linear polyacrylic acid because the linear polyacrylic acid dissolves and distributes on the surface of the non-melonized zinc alloy powder and the gelling agent, and plays a role as a lubricant. It is thought to fulfill.

[0015]

[Table 2]

Table 2 shows the results of an investigation on the impact resistance of each battery. ◎ indicates a change of 100 mV or less, and ○ indicates 100 to 2
00 mV, Δ indicates 200 to 500 mV, and X indicates 500 mV or more. In the investigation method, a battery discharged with a discharge load of 2Ω was dropped freely from a height of 2 m, and the amount of change in operating voltage at that time was measured with an oscilloscope (average value of n = 3).

From Table 2, it can be seen that the viscosity of the gelled zinc negative electrode is 5
At 000 cps, the impact resistance is completely impossible, and when the viscosity of the gelled zinc negative electrode is 100,000 cps or more, the impact resistance is almost good. However, the impact resistance increases as the amount of the linear polyacrylic acid added increases. It was observed that the properties tended to be worse. This is considered to be because the good flowability of the linear polyacrylic acid has an adverse effect on the impact resistance, and it is found that addition of 0.7% or more of the linear polyacrylic acid is not good.

[0018]

[Table 3]

Table 3 shows the discharge duration (final voltage: 0.9 V, average value of n = 6, unit:
Minutes). It can be seen from Table 3 that the amount of the linear polyacrylic acid added has little effect on the discharge duration. It was also observed that the discharge characteristics tended to be degraded when the viscosity of the gelled zinc negative electrode was increased.
This is presumably because the amount of the gelling agent added was large, so that the electrolyte required for the electrode reaction was hardly released from the gelling agent.

Judging comprehensively from the above, the viscosity of the gelled zinc negative electrode at 25 ° C. was 100,000 to 300,000.
By adding 0.05 to 0.5% of linear polyacrylic acid to the alkaline electrolyte to the gelled zinc negative electrode of 0 cps, the filling of the gelled zinc negative electrode is facilitated and safe. A high-performance zinc alkaline battery can be obtained. In the above example, linear polyacrylic acid was described. However, the same effect was obtained with linear sodium polyacrylate.

[0021]

As described above, according to the present invention,
It is possible to provide a zinc-alkaline battery that achieves low pollution by using a non-melonized zinc alloy powder, has good workability, has excellent impact resistance, and has high discharge performance.

[Brief description of the drawings]

FIG. 1 is a sectional view of an alkaline battery according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal can, 2 ... Positive electrode mixture, 3 ... Separator, 4 ... Gelled zinc negative electrode, 5 ... Negative electrode current collecting rod, 6 ... Insulating gasket, 7
... ring-shaped metal plate, 8 ... metal sealing plate.

Claims (2)

[Claims] 1. A zinc-alkaline battery using a calcined zinc alloy powder as a gelled zinc negative electrode, wherein a polyacrylic acid or a chain is added to a gelled zinc negative electrode having a viscosity at 25 ° C. of 100,000 to 300,000 cps. Sodium polyacrylate from 0.05% to 0.1% based on the alkaline electrolyte.
A zinc alkaline battery to which 5% has been added. 2. The viscosity at 25.degree.
The zinc-alkali battery according to claim 1, wherein the gelled zinc negative electrode of 300,000 cps uses crosslinked polyacrylic acid or crosslinked sodium polyacrylate as a gelling agent.