JPH1027617A - Flat battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To put a positive electrode ring in contact with a positive electrode case at always constant pressure and provide excellent inner resistance property by providing a protrusion at the bottom of the positive electrode ring which is laid between a positive electrode and the positive electrode case and fitting it to the positive electrode case. SOLUTION: A battery has a negative electrode 6, a separator 4, a positive electrode 5 and nonaqueous electrolyte filled therein. The opening of a positive electrode case 2 put in contact with the positive electrode 5 and served as a positive electrode terminal is caulked inside via a gasket 3 which is laid as an insulator between the positive electrode case 2 and a sealing plate 1 put in contact with the negative electrode 6 and served as a negative electrode terminal. A positive electrode ring 7 is laid between the positive electrode 5 and the positive electrode case 2 and a protrusion 8 is provided at part of the bottom of the positive electrode ring 7 toward the positive electrode case 2. The protrusion 8 protruded to part of the bottom is fitted to the positive electrode case 2 to put the positive electrode ring 7 in contact with the positive electrode case 2 at always constant pressure. In this way, the battery has excellent inner resistance property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat battery in which a power generating element is hermetically sealed with a positive electrode case, a sealing plate and a gasket, and more particularly to a technique for improving and stabilizing internal resistance characteristics.

[0002]

2. Description of the Related Art Conventionally, in a flat battery, a positive electrode ring has been used to stabilize internal resistance characteristics before and during discharge.

[0003]

However, as a discharge condition required for a battery, there is an improvement in pulse characteristics.
Under such discharge conditions, there is a problem that the internal resistance characteristics of the battery are not sufficient.

An object of the present invention is to solve such a conventional problem and to provide a flat battery having excellent internal resistance characteristics.

[0005]

According to the present invention, there is provided a positive electrode ring fitted to a side surface of a positive electrode, wherein a positive electrode case is provided at a part of a bottom surface existing between the positive electrode and the positive electrode case. The problem is solved by providing a projecting portion in the direction.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS By fitting a positive electrode ring having a projection on a part of the bottom surface to the positive electrode as described above, the positive electrode ring and the positive electrode case can always be brought into contact with a constant pressure. Therefore, a flat battery with small internal resistance can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings for a coin-shaped lithium manganese dioxide battery.

In FIGS. 1 and 2, 1 is a sealing plate also serving as a negative electrode terminal, 2 is a positive electrode case also serving as a positive electrode terminal, 3 is a gasket made of a polyolefin resin such as polyethylene or polypropylene, 4 is a separator made of a polypropylene non-woven fabric, and 5 is A positive electrode molded by mixing a conductive agent such as graphite and a binder into manganese dioxide as an active material, and then pressed, 6 is a negative electrode using lithium metal or a lithium alloy as an active material, and 7 is fitted on a side surface of the positive electrode 5. With the positive ring
On a part of the bottom surface, a folded portion 8 as a projecting portion is provided.

To assemble the battery, a negative electrode 6, a separator 4, a positive electrode 5, and a non-aqueous electrolyte are filled in the battery, and the opening of the positive electrode case 2 is provided between both the positive electrode case 2 and the sealing plate 1 as an insulator. This is performed by caulking inward through an interposed gasket 3.

Next, Table 1 shows a specific example of the present invention as a coin-type lithium manganese dioxide battery CR2032.
(A battery having a diameter of 20.0 mm, a thickness of 3.2 mm, and an electric capacity of 220 mAh), a battery having no folded portion 8 and a height A of the folded portion 8 of 0.1 mm, 0.2 mm,
Batteries assembled using the 0.3 mm positive electrode ring are referred to as Battery 1, Battery 2, Battery 3, and Battery 4, each of which comprises 100 batteries. The maximum and minimum values of the internal resistance are shown in the table.

[0011]

[Table 1]

As is apparent from Table 1, it is understood that the batteries 2, 3 and 4 each having the folded portion 8 of the positive electrode ring have a small internal resistance and excellent effects can be obtained.

On the other hand, in the battery 1 provided with the positive electrode ring having no folded portion, the non-aqueous electrolyte intervenes between the positive electrode case and the bottom surface of the positive electrode ring, so that the contact becomes unstable and the internal resistance characteristics are improved. There is no.

[0014]

As is apparent from the above description, a flat type battery using a positive electrode ring provided with a projection in the direction of the positive electrode case on a part of the bottom surface of the present invention can provide a battery having excellent internal resistance characteristics. . The effects of the present invention are not limited by the type of battery, and can be applied to a coin-type lithium primary battery, a coin-type lithium secondary battery, and the like other than the coin-type lithium manganese dioxide battery.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flat battery according to one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a positive electrode ring of the battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing plate 2 Positive electrode case 3 Gasket 4 Separator 5 Positive electrode 6 Negative electrode 7 Positive ring 8 Folded part (projection part) A Height of folded part

Claims (1)

[Claims] 1. A sealing plate also serving as a negative electrode terminal contacting a negative electrode, a positive electrode case also serving as a positive electrode terminal contacting a positive electrode, a gasket interposed between the positive electrode case and the sealing plate,
In a flat battery in which a positive electrode ring fitted to the side surface of the positive electrode and having a bottom surface interposed between the positive electrode and the positive electrode case is provided, and the opening of the positive electrode case is crimped inward to seal the power generating element, A flat-type battery, wherein a protruding portion in the direction of the positive electrode case is provided on a part of the bottom portion of the ring.