JPH05190158A - Storage battery - Google Patents

Abstract

PURPOSE:To suppress the internal short circuit caused by the burr in the outermost peripheral edge part of a positive electrode plate in the swirl shaped electrode plate group of a storage battery which is formed to increase the electrode plate volume, by thinning a separator, in the swirl shaped electrode plate group which is constituted of a strip shaped separator, positive electrode plate and a negative electrode plate. CONSTITUTION:The double constitution is generated by inserting a strip shaped separator 1 and a subseparator 5 having a thickness of 0.22mm or less between the outermost peripheral edge part of a positive electrode plate 3 in a swirl shaped electrode group for storage battery and a negative electrode plate 2 opposed to the positive electrode plate 3. Accordingly, the storage battery having the less internal short circuit caused by the burr in the outermost peripheral edge part of the positive electrode plate 3 in the swirl shaped electrode plate group can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical storage battery, and more particularly to a spiral electrode plate group.

[0002]

2. Description of the Related Art In recent years, in a storage battery having a spiral electrode plate group, the volume of the electrode plate is increased by thinning the thickness of the separator to increase the capacity of the battery. In this case, since the gap between the positive electrode plate and the negative electrode plate is narrowed, an internal short circuit occurs at the winding start part of the positive and negative electrode plates of the spiral electrode plate group and the outermost peripheral end part of the positive electrode plate due to burrs generated during processing of the positive electrode plate. There is a problem that is likely to occur. In addition, there is a limit in terms of construction method to suppress burrs generated during processing of the positive electrode plate. Therefore, the separator is doubled at the winding start portion of the positive and negative electrode plates of the spiral electrode plate group to prevent an internal short circuit. In addition, as a measure for an internal short circuit at the outermost peripheral end of the positive electrode plate, the strength of the separator is improved by increasing the weight per unit area of the separator (hereinafter referred to as a weight per unit area), or the outermost peripheral end of the positive electrode plate is removed. A means has been taken to reinforce the outermost peripheral edge of the positive electrode plate by covering it with an insulating tape having an electrolytic solution resistance such as alkali resistance.

[0003]

Means for improving the strength of the separator by increasing the weight per unit area of the separator as a measure for preventing an internal short circuit at the outermost peripheral end of the positive electrode plate. The means for covering with an insulating tape having an electrolytic solution resistance such as alkali resistance has the following drawbacks.

That is, when the weight per unit area of the separator is increased, the air permeability of the separator deteriorates and the internal pressure of the battery during charging increases. When the outermost peripheral edge of the positive electrode plate is covered with an electrolytic solution resistant insulating tape, the electrochemical reaction in the covered part of the positive electrode plate is hindered, and a sufficient battery capacity cannot be obtained. Further, there is a disadvantage that the step of covering the outermost peripheral end of the positive electrode plate with an electrolytic solution resistant insulating tape is required and the number of steps is increased.

[0005]

In order to solve the above-mentioned problems, the present invention provides a spiral electrode plate group for a storage battery, which comprises a strip separator, a positive electrode plate and a negative electrode plate, and a positive electrode plate of the spiral electrode plate group. In addition to the strip-shaped separator, a sub-separator having a thickness of 0.22 mm or less is interposed only between the outermost peripheral edge of the negative electrode plate and the opposite negative electrode plate to form a double structure.

[0006]

With the above structure, it is possible to suppress an internal short circuit at the outermost peripheral end of the positive electrode plate of the spiral electrode plate group which may occur when a thin separator is used. In addition, an electrochemical reaction of the entire positive electrode plate is possible, a sufficient battery capacity can be obtained, and the battery capacity can be increased. Further, the step of covering the outermost peripheral edge of the positive electrode plate with an insulating tape having electrolytic resistance such as alkali resistance can be omitted, and an increase in man-hours can be avoided.

[0007]

EXAMPLE One example of the present invention will be described in detail below. Using a sintered nickel positive electrode plate and a paste type cadmium negative electrode plate,
As a strip-shaped separator, two types of nylon nonwoven fabric separators with different basis weights and thicknesses of 0.18 mm are used.
An SC type sealed nickel-cadmium storage battery was prepared, and the battery standard capacity (0.2 C discharge capacity), the battery internal pressure during 0.1 C charging, and the short-circuit rate during group formation were examined. Sample A is a conventional comparative example 1 in which the electrode plate volume was increased and the capacity was increased by using a thin separator with a weight per unit area index of 100 as the strip-shaped separator, and its configuration is shown in FIG. In FIG. 2, 1 is a strip separator, 2 is a negative electrode plate, and 3 is a positive electrode plate.

Sample B has a basis weight of 20% more than Sample A.
It is a conventional comparative example 2 using a high strip separator,
Its configuration is similar to that of sample A and is shown in FIG.

Sample C is a conventional comparative example 3 in which the same strip-shaped separator as in sample A is used and the outermost peripheral edge of the positive electrode plate is covered with an alkali resistant insulating tape 4 as shown in FIG.

The sample D is an embodiment of the present invention, and as shown in FIG. 1, the sample A and the sample A are provided only between the outermost peripheral end of the positive electrode plate 3 of the spiral electrode plate group and the negative electrode plate 2 facing the outermost end. In addition to the same strip-shaped separator 1, a sub-separator 5 having a thickness of 0.22 mm or less is inserted to form a double structure.

The weight per unit area of the separator used in the examples of the present invention was 1 in the samples of the above-mentioned four kinds of configurations A to D.
The weight per unit area of the separator used for each sample, the standard battery capacity (0.2 C discharge capacity), the battery internal pressure during 0.1 C charging, and the short circuit rate in the group configuration of the embodiment of the present invention were 1
The short-circuit rate of each sample when it was set to 00 (Table 1)
Is shown in.

[0012]

[Table 1]

As is clear from this (Table 1), the embodiment of the present invention was caused by the burr at the outermost peripheral end of the positive electrode plate of the spiral electrode plate group, which was a problem caused by using the thin separator. In addition to being able to suppress an internal short circuit and obtaining a sufficient battery capacity, the battery internal pressure was able to obtain a characteristic equal to or higher than that of the conventional comparative example.

[0014]

The configuration of the spiral electrode plate group according to the present invention suppresses an internal short circuit caused by a burr at the outermost peripheral end of the positive electrode plate of the spiral electrode plate group, which is a problem when a thin separator is used. In addition, it is possible to secure a sufficient battery capacity and increase the capacity. Further, there is no increase in the number of steps of applying the conventional electrolytic solution resistant coating.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a spiral electrode plate group for an alkaline storage battery according to an embodiment of the present invention.

FIG. 2 is a partial perspective view of a conventional spiral electrode plate group for alkaline storage batteries of Comparative Examples 1 and 2.

FIG. 3 is a partial perspective view of a conventional spiral electrode plate group for alkaline storage batteries of Comparative Example 3.

[Explanation of symbols]

 1 Strip Separator 2 Negative Electrode Plate 3 Positive Electrode Plate 4 Insulating Tape 5 Sub-Separator

Claims (1)

[Claims] 1. A strip separator, a positive electrode plate, and a negative electrode plate are spirally wound, and in addition to the strip separator, only between the outermost peripheral end of the positive electrode plate and the negative electrode plate facing the positive electrode plate, the thickness is added to the strip separator. A storage battery provided with a spiral electrode plate group having a double structure by inserting a sub separator of 0.22 mm or less.