JPS6139376A - Sealed alkaline storage battery - Google Patents

Abstract

PURPOSE:To improve the life characteristic and the high-rate discharge characteristic of a sealed alkaline storage battery by using an aqueous solution principally composed of potassium hydroxide having high discharge efficiency as the electrolyte. CONSTITUTION:A negative plate prepared by packing cadmium used as the active material has a width of 33mm., a length of 260mm. and a thickness of 0.60mm.. After the negative plate is charged in 20% aqueous sodium-hydroxide solution at 20 deg.C with a current of 0.4A for 15hr by using a nickel plate as the counter plate, the charged negative plate is washed in flowing water before being dried. A battery is constituted by combining the thus treated negative plate with a completely discharged positive plate with 1.2A capacity and adding 3.8ml of 30% aqueous potassium-hydroxide solution as the electrolyte. By the means mentioned above, a great discharge reserve can be secured while minimizing the variation of the plates. Accordingly, it is possible to improve the life characteristic and the high-rate discharge-characteristic of the battery.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a sealed alkaline storage battery.

Conventional technology In general, sealed nickel-cadmium storage batteries (hereinafter referred to as ``Ni-Cad batteries'') have a negative plate capacity that is smaller than the positive plate capacity in order to maintain life characteristics or high-rate discharge characteristics and to ensure that the battery is sealed during overcharging. is made larger. The former is called discharge reserve, and indicates what capacity the cathode plate has in a battery when the anode plate has reached full discharge. The latter is also called the charge reserve, and indicates how long the anode plate can be charged from a fully charged state.

The above-mentioned discharge reserve has conventionally been secured by charging in an aqueous solution of potassium hydroxide or the like during chemical formation, and then discharging a portion thereof.

Problems to be Solved by the Invention However, this method has problems such as the end portions of the electrode plates being easily discharged and the charged portions becoming uneven. In order to solve these problems, a method has been proposed in which the surface of the electrode plate is covered with an insulating plate smaller than the size of the electrode plate after charging and discharging, and only the exposed portion is charged. (hereinafter referred to as the "mask method"). However, this method has drawbacks such as overdischarging during discharge, which inactivates a portion of the active material (generates 0° (OH)) and causes a decrease in cathode plate capacity. On the other hand, in the cathode plate, taking advantage of the property that when the discharge current becomes large, deep discharge becomes impossible and the discharge reserve increases, discharge during formation is performed at a larger current than the current used in the actual battery. A method of securing a reserve is also considered, but this method requires (1) a large capacity rectifier due to large current discharge;

(2) There were drawbacks such as the inability to apply it to rapid discharge batteries that require a 10 cmk discharge.

Means for Solving the Problems The present invention was made for the purpose of solving such drawbacks.
Cadmium hydroxide (γ-Od (OH), ) generated by discharge in an aqueous solution of cadmium hydroxide (β-Cd (OH), ) generated by discharge in potassium hydroxide
It utilizes the difference in the properties of H) and ). That is,
When charging and discharging during formation of the cathode plate, hydroxide with low discharge efficiency is used)
It is characterized in that it is carried out in an IJum aqueous solution and then combined with an anode plate to form a battery.

By using an aqueous solution mainly composed of potassium hydroxide, which has higher discharge efficiency, as a working battery electrolyte, the life characteristics and high rate discharge characteristics of the battery can be improved.

Example Next, one embodiment of the present invention will be described.

A cathode plate having a width of 3311Il11 and a length of 260cm and a thickness of 0.60mm and filled with cadmium as an active material was charged at 20°C for 15 hours at 20°C in an aqueous solution of sodium hydroxide using a nickel plate as a mating plate. After 0°, the battery was discharged at 1.2 A to a final voltage of -L8V.

Thereafter, it was washed under running water and dried. The cathode plate obtained in this way was combined with a fully discharged anode plate with a capacity of 1.2 people, and a 30% potassium hydroxide aqueous solution was used as the battery electrolyte.
．． 8 mA was added to form a battery. FIG. 1 shows the charge/discharge cycle life characteristics of the battery thus produced, and FIG. 2 shows the discharge reserve amount when overdischarged, in comparison with a conventional battery obtained by the mask method. It was found that the battery of the present invention has improved life characteristics because it is easy to secure a discharge reserve.

Effects of the Invention As described above, according to the present invention, it is possible to secure a large discharge reserve with little variation within the electrode plates without requiring equipment for passing large currents, thereby improving the high rate discharge characteristics, life characteristics, etc. of the battery. It has excellent effects such as being able to obtain a battery with improved uniform characteristics.

[Brief explanation of drawings]

FIG. 1 is a curve diagram showing the charge/discharge cycle life characteristics of a sealed alkaline storage battery according to the present invention and a conventional sealed alkaline storage battery, and FIG. 2 is a discharge curve diagram of 1 ml as well.

Claims (1)

[Claims] A sealed alkaline storage battery characterized by having a cathode plate chemically formed by charging and discharging in an aqueous solution mainly composed of sodium hydroxide, and using a battery electrolyte mainly composed of potassium hydroxide.