JPS5966054A - Zinc alkaline battery - Google Patents

Abstract

PURPOSE:To improve impact resistance characteristic and discharge characteristic at a low temperature by forming the negative pole by dispersely mixing together the specified amount of electrolyte polymer, short fiber in the specific weight and diameter and zinc powder respectively in relation to a certain amount of the alkaline electrolyte. CONSTITUTION:A gel negative pole is formed by dispersely mixing, with the alkaline electrolyte, an electrolytic polymer such as the Na salt of carboxylmethylcellulose of 1.3-2.6wt% in relation to the amount of electrolyte, short fiber having eliminated the element which is soluble in the alkaline electrolyte and of 1.0-3.0vol% with diameter of 10-30mum in relation to the amount of the electrolyte and the zinc powder. A positive pole black mix 2, a separator 3 and an electrolyte-impregnated material 4 are combined and thereby a button type alkaline battery is formed. Accordingly, the impact resistance characteristic can be improved, and gel viscocity can be lowered by suppressing addition of electrolyte polymer because the zinc particles are held uniformly with addition of short fiber, thus a high load discharge characteristic at a low temperature can be enhanced.

Description

[Detailed Description of the Invention] Industrial Application Fields This invention is! This invention relates to the configuration of the negative electrode part of the 717 lead-alkaline battery.

Problems with the structure of conventional examples The zinc dissolution reaction when an alkaline aqueous solution is used as the electrolyte is extremely complex, and as the discharge progresses, a passivation film is formed on the surface, increasing the resistance and inhibiting the reaction. Ru.

To avoid this, zinc as a negative electrode active material in zinc-alkaline batteries is used in the form of spindle-shaped particles to increase the surface area and facilitate the inflow and outflow of ions. In addition, the structure of the negative electrode part is made by adding short fibers such as polystyrene, vinylon, polyacrylic acid, etc., and inorganic powders such as ZnO, CaO, etc. to facilitate the diffusion of ions into the gaps between the zinc grains and to increase the electronic conductivity. A pressure-molded product is used, or a gelatinized product in which zinc particles are suspended and gelled using a carboxymethylcellulose Na salt or a polyacrylic polymer such as sodium polyacrylate is used.

Such a conventional structure of the negative electrode part has various drawbacks. First, when only short fibers or inorganic powders are added, a fairly large amount of zinc powder is required to be widely and uniformly dispersed in the negative electrode, and the zinc and electrolyte cannot be filled to that extent, causing the battery to deteriorate. Discharge capacity decreases. Since the electrolyte has not yet been gelled, leakage resistance is poor. Furthermore, short fibers have poor miscibility with zinc powder, making it impossible to mix them uniformly.

Furthermore, when only an electrolyte polymer (gelling agent) is added, it is possible to uniformly disperse the zinc particles, but since the viscosity of the gelled electrolytic solution holds the zinc powder, it is difficult to prevent shock and When acceleration is applied, the zinc powder becomes unevenly distributed due to the viscous flow of the gel electrolyte. In fact, when a battery is subjected to a gravity load test in which the zinc powder is accelerated in a direction in which it moves away from the current collector terminal, and the short circuit current is measured, many defects occur.

Unfortunately, in order to avoid such defects, adding a large amount of gelling agent to increase the viscosity had the disadvantage of increasing the internal resistance of the battery and worsening high-load discharge characteristics at low temperatures. .

OBJECTS OF THE INVENTION The object of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples and to provide a zinc-alkaline battery that has good impact resistance and high load discharge characteristics at low temperatures.

Constituent composition of the invention: 1.3 to 2.6 wt relative to the amount of electrolyte in the alkaline electrolyte
% of electrolyte polymer and electrolyte amount from 1.0 to 3.
A so-called gel negative electrode is prepared by dispersing and mixing 0VO1% short fibers with a diameter of 10 to 30μ and zinc powder.

Description of Examples 1.3 wt% Na salt of carboxymethyl cellulose and components soluble in an alkaline aqueous solution with a diameter of 10μ were removed from 1.0 kg of a 40 wt% potassium hydroxide electrolyte containing tsoy/fl of zinc oxide. Cellulose short fibers (diameter 10 μ, length 2 threshold) were added to the electrolyte solution for 3.
Weight equivalent to Vo 1% and further hydration rate 1゜wt
Zinc hydrate powder with particle size 80-200 mesh in % 1.2
8KG+ was gradually mixed in a plastic stirring container with an internal volume of 1.5 iV, and from the time when all the contents were added, the mixture was uniformly mixed for about 30 minutes to prepare a gel negative electrode.

Figure 1 shows a 5R44 (diameter 11 mm) using the gel negative electrode of the example.
．． This figure shows a half-mounted cross-section of a button-type alkaline battery with a diameter of 6 mm and a total height of 5.4 mm. In the figure, 1 is a positive electrode case made of nickel-plated iron, and 2 is a positive electrode mixture compression-molded inside the case 1, which is composed of 95 wt% silver oxide and 5 wt% graphite powder. 3 is a separator, 4 is an electrolyte impregnated electrode, and 5 is a gel negative electrode of the present invention, of which approximately 370ff19 is used per battery. 6 is a sealing plate which also serves as a negative electrode terminal, 7 is a gasket made of nylon, and 8 is a positive electrode ring.

Figure 2 includes the battery of the example, the amount of cellulose short fibers added was Q~4Vo1%, and the Na salt concentration of carboxymethylcellulose was changed from 5.3 to 5.3o as the amount of short fibers added was increased.
, shows the characteristics of a 5R44 battery when changed to 55wt%. Among these, the leakage rate indicates the number of batteries that were soaked after 40 days of holding 100 batteries of the same configuration in an atmosphere at a temperature of 45° C. and a humidity of 9Q%. The short circuit current is an acceleration of 300G in the direction of the zinc powder in the battery moving away from the current collector terminal.
After multiplying by 3σ minutes, it shows the current that flows at the moment when a resistance of Ω is loaded on 1. Furthermore, the discharge time is 2°C at a temperature of -2°C.
It shows the time at the end voltage o, ysVJ when a pulse discharge of 6Ω is applied for 2 seconds ON and 1 second OFF.

Here, although Na salt of carboxymethyl cellulose was used as the electrolyte polymer in the example, the same effect can be obtained by using an electrolyte polymer such as sodium polyacrylate, and it is still possible to use polystyrene, vinylon, etc. as the short fiber. The same effect was obtained if the diameter of the short fibers was within the range of 10 to 30 μm.

Effects of the Invention By adding short fibers, zinc particles can be held uniformly and high load discharge characteristics at low temperatures can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a zinc-alkaline battery according to an embodiment of the present invention, and FIG. 2 is a comparison diagram of battery characteristics. 1...Case, 2...Positive electrode, 3...
- Senorator, 4... Impregnating material, 6...
Negative electrode, 6... Sealing plate, 7... Gasket, 8... Anode ring. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Takasago jt 'W 'l /l + face f (wtye vo
t:, 1yte)2

Claims (2)

[Claims] (1) Contains an electrolyte polymer with a weight of 1.3 to 2.6 wt relative to the electrolytic solution and short fibers with a 1μ diameter of 10 to 30μ and a weight corresponding to 1% of 1.0 to 3.0Vo relative to the electrolyte. A zinc-alkaline battery that consists of a negative electrode. (2) '? 11. The 11[I lead-alkaline battery according to claim 1, wherein the EF4 polymer is Na salt of carboxymethyl cellulose, and the short fibers are cellulose from which components soluble in an alkaline electrolyte have been removed.