JPH0724225B2 - Swirl type electrode group for alkaline storage batteries - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a spiral electrode plate group for alkaline storage batteries.

Conventional technology When configuring a spiral electrode plate group for alkaline storage batteries, the electrode is wound with a small radius of curvature near the winding start, which is in contact with the winding core, causing cracks on the outer peripheral surface of the electrode, causing a short circuit. Was there. This tendency is particularly remarkable in the positive electrode when a sintered nickel electrode is used for the positive electrode and a paste type cadmium electrode is used for the negative electrode. For this reason, in the past, the Japanese Patent Publication No.
As disclosed in Japanese Patent No. 26, a short circuit is prevented by using an auxiliary separator having the same length on the outer peripheral surface and the inner peripheral surface from the winding start end surface of both the positive electrode and the negative electrode or either one of the electrodes.

Therefore, either the positive electrode and the negative electrode by the thickness of this auxiliary separator, or either one of the electrode plates must be thinned or the length must be shortened, making it difficult to increase the capacity of the battery and improve the high rate discharge characteristics. Was becoming.

Problems to be Solved by the Invention In such a conventional configuration, since the length of the auxiliary separator for preventing a short circuit is set to be the same on both the inner and outer peripheral surfaces from the winding start end edge of the electrode, If the length is increased, the group diameter increases and it becomes difficult to insert the electrode plate group into the battery case. Also, the degree of tightness of the electrode plate group in the battery case increases, and the gas absorption characteristics during battery charging deteriorate. . Therefore, it is necessary to shorten the length of the auxiliary separator, but if it is shortened, it is not possible to completely cover the electrode plate crack near the core,
In order not to cause a short circuit or increase the group diameter,
When the length or thickness of the electrode plate is suppressed, there is a drawback that the battery capacity and the high rate discharge characteristics are deteriorated.

The present invention aims to solve such problems.

Means for Solving the Problems The present invention uses a belt-shaped positive and negative bipolar electrode and a separator, and in the spiral electrode plate group in which both electrodes are insulated by the separator and the whole is spirally wound, a crack is formed on the winding outer periphery. Either the positive or negative winding start edge of the electrode, which is likely to occur, is covered with an auxiliary separator having a short inner peripheral surface and a long outer peripheral surface, and a main separator that entirely covers and insulates the other electrode. It is intended to provide a spiral electrode plate group which is characterized by being wound so as to be double covered.

Function With this structure, the outer peripheral surface of the electrode plate where cracks are likely to occur can be covered with an auxiliary separator for a long time to prevent short-circuiting completely, and the electrode plate length is the same as the conventional product with the same group diameter and tightness. Alternatively, the thickness can be increased, and the battery can have high capacity and high performance.

Examples Examples of the present invention will be described below with reference to the drawings. First
FIG. 1 is a sectional view of an electrode plate group of a cylindrical nickel-cadmium battery according to the present invention. In the figure, 1 is a sintered positive electrode, 2 is a paste negative electrode, 3 is a strip separator made of polyamide nonwoven fabric, a main separator that insulates the entire positive and negative electrodes, and 4 is a main separator that covers the winding start edge of the positive electrode 1. With the auxiliary separator made of the same material as in FIG. 1, the inner peripheral surface side of the winding start edge of the positive electrode 1 is short and the outer peripheral surface side is long. Width according to Fig. 1
38 x length 220 x 0.65 mm thick sintered positive electrode and width 38 x length 260
× 0.50 mm thick paste-type negative electrode and a polyamide non-woven polyamide main separator of approximately 0.20 mm thickness and auxiliary polyamide polyamide non-woven separator of the same thickness as the inner side from the winding start edge of the sintered positive electrode Was wound so that the outer circumference side was 30 mm so that the outer circumference side was 80 mm, and a single AA sealed nickel-cadmium storage battery was manufactured. This is referred to as battery A. On the other hand, FIG. 2 is a cross-sectional view of a spiral electrode plate group according to a conventional example, in which the auxiliary separator 4 has substantially the same length from the winding start end edge of the positive electrode 1 to both the inner and outer peripheral surfaces. Using the sintered positive electrode having the same dimensions as the battery A, the paste negative electrode, and the main separator made of polyamide nonwoven fabric and the auxiliary separator made of polyamide nonwoven fabric having the same width and thickness as the main separator according to the configuration of FIG. The positive and negative electrodes are wound so that the inner and outer peripheries are 55 mm from the winding start edge, and the same type A and B batteries are manufactured. Separately, in the configuration shown in Fig. 2, a sintered positive electrode having a width of 38 x a length of 200 mm x a thickness of 0.65 mm, a paste type negative electrode having a width of 38 x a length of 240 mm x a thickness of 0.50 mm, and a width of 43 mm and a thickness of A polyamide non-woven main separator of about 0.2 mm is used, and a polyamide non-woven auxiliary separator of the same width and the same thickness is wound from the winding start end edge of the positive electrode to both inner and outer peripheral surfaces of 80 mm. An AA sealed nickel-cadmium storage battery was manufactured with an electrode plate group having an outer diameter almost the same as the outer diameter. This is referred to as battery C.

As a result of manufacturing each of the A, B, and C batteries, the rate of occurrence of internal short circuit and the capacity at the time of discharging 0.1c × 16 hours and 0.2c were as shown in the following table.

EFFECTS OF THE INVENTION As described above, according to the present invention, the auxiliary separator is preferentially arranged on the outer peripheral surface of the electrode plate, and by optimizing the length, the internal short circuit is significantly reduced as compared with the conventional example. ,
Higher capacity and higher performance can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view of a spiral electrode plate group for alkaline storage batteries of the present invention, and FIG. 2 is a sectional view of a spiral electrode plate group for alkaline storage batteries of a conventional example. 1 ... Sintered positive electrode, 2 ... Paste type negative electrode, 3 ... Main separator, 4 ... Auxiliary separator.

Claims (1)

[Claims] 1. A spiral electrode plate group in which a strip-shaped sintered positive electrode, a paste negative electrode and a separator are used, and both electrodes are insulated by a separator and the whole is spirally wound. The auxiliary separator covering the part has a length in contact with the positive electrode outer peripheral surface side longer than the inner peripheral surface side,
A spiral electrode plate group for alkaline storage batteries, characterized in that a main separator that covers the entire positive electrode and insulates it from the negative electrode is arranged on the outside.