JPH08171930A - Battery - Google Patents

Abstract

PURPOSE: To obtain a battery having high reliability as well as to prevent an occurrence of internal short circuit due to deviation of location of electrode plates when an impact is applied. CONSTITUTION: A battery is provided with a group of electrode plates wound up positive electrode plates 4 and negative electrode plates 5 via separators spirally inserted into a cylindrical metal case. In the bottom surface side of the metal case of the positive electrode plates of outer periphery of this group of electrode plates, a width of its pole plate is made smaller than any other parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery in which a positive electrode plate and a negative electrode plate are wound with a separator interposed between them to form a spiral electrode plate group.

[0002]

2. Description of the Related Art With the development and practical use of various portable devices, various secondary batteries have been used as power sources. Under such circumstances, there is a growing demand for batteries, in terms of performance represented by high capacity and large current load, and reliability in terms of long life and impact resistance. In response to such demands, improvements have been made especially in the structure of a cylindrical sealed alkaline storage battery.

A cylindrical battery represented by an alkaline storage battery is usually constructed as shown in FIG. That is, the positive electrode plate 4 and the negative electrode plate 5 are displaced in position so that the core metal protruding portions 4a and 5a respectively protrude vertically, and the separator 6 is disposed therebetween to wind the spiral electrode plate group 1. This spiral electrode group 1
Of the positive electrode plate 4 and the negative electrode plate 5 are welded with current collectors 7 and 8 made of donut-shaped flat plate nickel-plated steel plates, respectively, to form a cylindrical metal case 2 with a bottom. Insert the negative electrode terminal side as the bottom part. Metal case 2
An annular groove portion 10 which also functions as a positive electrode terminal and which protrudes inward is provided in order to support the metal sealing plate 3 around which an insulating gasket 9 is arranged and which also serves as a positive electrode terminal. Further, in order to prevent contact between the core metal protruding portion 4a of the positive electrode plate 4 and the annular groove portion 10 of the case 2 forming the negative electrode terminal, a disc having a hole at the center formed of an insulating resin such as nylon or polypropylene. The upper insulating ring 11 having a circular shape is arranged on the electrode plate group.

Further, for the purpose of preventing contact between the lead piece of one electrode plate and the other electrode plate and increasing the capacity by improving the capacity utilization rate inside the battery, there is a possibility that the capacity is increased. As disclosed in Japanese Laid-Open Patent Publication No. 63-166143, the metal case has no annular groove on the upper part,
A battery has also been proposed in which the positive electrode plate and the negative electrode plate are connected to a metal sealing plate and a metal case by a direct pressure contact method, respectively.

[0005]

However, in these conventional batteries, the positive electrode plate 4, the negative electrode plate 5, and the separator 6 which form the spiral electrode plate group 1 inside the battery when the battery is impacted. There is a possibility that the positional relationship between the current collectors 7 and 8 shifts and the current collectors 7 and 8 facing each other come into contact with each other.

The positive electrode doughnut-shaped current collector 7 is usually smaller in size than the spiral electrode plate group 1 in order to prevent contact with the side surface of the metal case 2 which also functions as a negative electrode terminal. Therefore, since the outer peripheral portion of the positive electrode plate 4 is not fixed to the current collector 7, the positive electrode plate 4 has a structure that is easily moved by an impact.

An upper insulating ring 11 exists between the outer peripheral portion of the spiral electrode plate group 1 and the annular groove portion 10.
This prevents contact with the annular groove 10 when the outer periphery of the positive electrode plate 4 is displaced toward the opening of the case, but is contacted with the negative electrode current collector 8 when displaced toward the bottom of the case and short-circuited. Cause of.

The present invention solves the above-mentioned problems, and when the positional relationship between the positive electrode plate and the negative electrode plate is deviated in the outer peripheral portion of the spiral electrode plate group 1 due to the impact on the battery, the positive electrode plate and the negative electrode plate are also collected. The purpose is to prevent contact short-circuit with an electric body or case and to improve reliability.

[0009]

In order to solve the above-mentioned problems, the present invention sets a part of the electrode plate width on the bottom side of the metal case in the outer peripheral portion of the positive electrode plate forming the spiral electrode plate group to be smaller than the other. The feature is that the battery is configured to be narrower.

[0010]

With the above-described positive electrode plate shape, it is possible to separate a substantial distance between the negative electrode current collector and the outer periphery of the positive electrode plate of the spirally wound electrode plate group that is easily moved by the impact, and the shock is applied. Even if the positive electrode plate outer peripheral portion lower in position and the negative electrode current collector are not in contact with each other, a short circuit is less likely to occur.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a strip electrode plate of a nickel-cadmium storage battery used to obtain the spiral electrode plate group 1 for the cylindrical battery shown in FIG.

In FIG. 5, the cored metal protruding portions 4a and 5a of the sintered positive electrode plate 4 and the paste type negative electrode plate 5 are positioned 2.5 mm each so as to protrude above and below the electrode plate group 1 obtained. It was shifted and wound with a separator 6 interposed therebetween to form a spiral electrode plate group 1. The positive electrode plate 4 at this time usually has a length of 380 mm and a width of 49 mm, but is positioned below the annular groove portion 10 and is 110 of the winding end portion which constitutes the outer peripheral portion of the group 1.
As shown in FIG. 1, an electrode plate having a width of 46 mm and a width of 46 mm, which is 3 mm narrower than usual, was used. As the negative electrode plate 5, a strip-shaped electrode plate having a regular length of 450 mm and a uniform width of 49 mm was used. Similarly to the above, the positive and negative electrode plates 4 and 5 have the positive and negative current collectors 7 and 8 attached thereto, and the spiral electrode plate group 1 is inserted into the metal case 2 with the negative electrode current collector 8 as the bottom. . An upper insulating ring 11 is inserted on the electrode plate group 1 and an annular groove 10 protruding inward is provided at the opening of the metal case 2. Then, after injecting a predetermined amount of the electrolytic solution, the opening was sealed by the metallic sealing plate 3 also serving as the positive electrode terminal to obtain the battery A of the present invention.

As a battery of a comparative example, a positive electrode plate as shown in FIG. 4 has a length of 380 mm and a width of 49 mm, and a negative electrode plate has a length of 450 mm and a width of 49 mm. Spiral electrode plate group 1 with the separators interposed between them by shifting the position by 2.5 mm so as to project above and below each group
And Using this electrode plate group, a battery was constructed with the same formulation as the battery A, and was designated as a battery B of a comparative example.

In order to compare the performances of the battery A according to the present invention and the battery B of the comparative example, a shock of 50 G was repeatedly applied 10 times in a shock test device. The number of internal short circuits occurring at that time is shown in (Table 1).

[0016]

[Table 1]

As is clear from Table 1, the battery A of the present invention has an effect of suppressing the occurrence of internal short circuit.

[0018] Of the batteries B of the comparative examples, the batteries in which an internal short circuit occurred were disassembled, and it was found that the cause was contact between the outer periphery of the positive electrode plate and the negative electrode current collector.

From this, it can be seen that the contact short circuit between the positive electrode plate and the negative electrode current collector is less likely to occur due to the substantial distance between the outer periphery of the positive electrode plate and the negative electrode current collector of the present invention.

Further, in order to reduce the width of the outer peripheral portion of the electrode plate group of the positive electrode plate, a shape having inclined notches as shown in FIG. 2 in addition to FIG. 1 and a metal case for securing battery capacity are provided. The same effect can be obtained by notching the upper and lower ends of the positive electrode plate 4 as shown in FIG. 3 in which the volume utilization rate is improved, and forming the negative electrode plate by notching the upper part of the end and combining them.

[0021]

As described above, according to the present invention, by simply changing the shape of the electrode plate, the inside of the battery when a shock such as vibration or drop is applied without adding or changing the process and parts. A short circuit can be prevented and a highly reliable battery can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an electrode plate shape for obtaining a battery of the present invention.

FIG. 2 is a diagram showing another electrode plate shape of the present invention.

FIG. 3 is a diagram showing another electrode plate shape of the present invention.

FIG. 4 is a diagram showing a conventional electrode plate shape.

FIG. 5 is a vertical sectional view showing a cylindrical battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 spiral electrode plate group 2 metal case 3 metal sealing plate 4 positive electrode plate 4a positive electrode core metal protrusion 5 negative electrode plate 5a negative electrode core metal protrusion 6 separator 7 positive electrode current collector 8 negative electrode current collector 9 insulating gasket 10 annular Groove 11 Upper insulating ring

Claims (1)

[Claims] 1. A battery in which a strip-shaped positive electrode plate and a negative electrode plate are disposed in a separator and a spirally wound electrode plate group is inserted into a cylindrical metal case having a bottom, wherein the electrode plate is a battery. The positive electrode plate at the outer peripheral portion of the group has a narrower electrode plate width on the bottom side of the metal case than the other.