JPS5963658A - Flat type battery - Google Patents

Abstract

PURPOSE:To increase the ratio of inner volume to total volume in a battery to increase discharge capacity and improve electrolyte leakage resistance by forming a battery case with a cylinder whose outer surface is coated with an insulating film, and an anode can and a cathode can fitted to the upper and lower surfaces of the cylinder. CONSTITUTION:An anode can 8 is covered to a cylinder 7 with the standing part 8b of the can 8 broadened outward by heating, then the standing part 8b is shrunk by cooling. By this process, the standing part 8b is press-fitted or shrinkage- fitted to the peripheral outer surface 7b of the cylinder 7 via an insulating film 7a. An anode active material 10 impregnated with electrolyte is inserted into the can 8, then a separator 12 and a tablet-shaped cathode active material 11 are placed in order, and finally a cathode can 9 is covered to the opening of the cylinder 7, and the cylindrical part 9b of the can is press-fitted or shrinkage-fitted to the peripheral outer surface 7c of the cylinder 7 via an insulating film 7a to form a flat type battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat battery used in small electronic devices such as wristwatches, calculators, cameras, and hearing aids.

Conventionally, a cathode active material and an anode active material impregnated with an electrolyte and placed facing each other with a separator in between are placed in a cup-shaped anode can.
A so-called button-shaped flat battery is known, which is hermetically sealed with a cap-shaped cathode can assembled into the anode can via a gasket.

A conventional battery of this type will be explained with reference to a vertical cross-sectional half-sectional view shown in FIG.

The battery case of this battery is composed of a cup-shaped anode can 1 and a cap-shaped cathode can 2 that is assembled into the anode can 1 via a gasket 6. Inside this battery case, a cathode active material container impregnated with an electrolyte solution and a tablet-shaped anode active material 4 are housed facing each other with a separator 6 in between.

In a conventional battery with such a configuration, the anode can 1
The gasket 6 provided between the anode can 1 and the anode can 2 is compressed by crimping the periphery of the upper opening 1a of the anode can 1 inward, and the compression reaction force of the gasket 6 causes the gasket 6 and the anode can 1 to be compressed. Alternatively, the cathode can 2 was brought into close contact with the cathode can 2 to prevent liquid leakage.

Therefore, in order to improve the leakage resistance of this battery, it was necessary to increase the thickness of the gasket A and increase the compression reaction force of the gasket 6.

However, if the thickness of gasket 3 is increased, the volume occupied by gasket 3 relative to the total battery volume increases, and in order to supply the same discharge capacity without reducing the capacity of the contents, the battery case itself must be made larger. I was convinced that it was necessary.

Furthermore, when the amount of compression of gasket B is increased in order to improve leakage resistance, the force that compresses gasket 6 causes the curled portion 2a of cathode can 2 to move inward, increasing the internal pressure of the battery can. At the same time, it increases the creep deterioration rate of the gasket B, making it impossible to strengthen the compression reaction force and causing leakage.4 This invention was made in view of the above-mentioned drawbacks, and the outer surface is coated with an insulating film. A battery case is formed by a cylindrical body, a cathode can fitted on the upper and lower surfaces of this cylindrical body, and a cathode can to increase the ratio of the internal volume to the total battery volume (to increase discharge capacity and improve leakage resistance). The purpose is to provide a polarized type battery with improved liquid performance.

The gist of the present invention to achieve the above object is as stated in the claims above.

Next, preferred embodiments of the present invention will be described in detail based on the drawings.

Figure 2 shows the flat type of this invention! It is a half-section diagram of a longitudinal section of a pond.
For assembly reasons, the electrode can arrangement of the conventional battery shown in FIG. 1 is shown upside down.

In FIG. 2, reference numeral 7 denotes a cylindrical body made of a metal material. The surface of the cylindrical body 7 is coated with an insulating coating 7a made of a synthetic resin having high heat resistance and elasticity, such as fluorine-based, silicon-based, nylon-based, or polyimide-based resin.

In addition, although this insulating coating 7a is coated on the entire surface in the drawing, it may be coated only on the outer peripheral side surface. Reference numeral 8 denotes a cathode can made of a metal material and having a U-shaped cross section, and is composed of a bottomed portion 8a and a rising portion 8b that is continuously bent approximately vertically upward from the outer periphery of the bottomed portion 8a. □, this cathode □ can 8 is fitted in a watertight manner via the insulating coating 7a by shrink-fitting or press-fitting the rising part 8b to the outer circumferential side surface 7b of one open end side of the cylinder 7. There is. Reference numeral 9 denotes an anode can made of a metal material and having an n-shaped cross section, and is composed of an upper flat surface 9a and a cylindrical portion 9b that is continuously bent approximately perpendicularly downward from the outer periphery of the upper flat surface 9a. The anode can 9 is fitted in a watertight manner via the insulating coating 7a by shrink-fitting or press-fitting the cylindrical portion 9b to the outer circumferential surface 7C of the other open end of the cylinder 7. 10 is a cathode active material impregnated with an electrolyte; 1
1 is a positive electrode active material that is compressed into a tablet shape.

12 is a separator, which includes a cathode active material 10 and an anode active material 11.
This prevents electrical short circuits.

As described above, the flat battery according to the present invention is constructed by heating the entire cathode can 8 and expanding the rising portion 8b outwardly, covering the cathode can 8 on the cylindrical body 7, and cooling it. upper part 8
b is contracted, and the rising portion 8b is attached to the outer circumferential side surface 7bv of the cylinder body 7.
c The cathode active material 10 is fitted with the cathode can 8 by crimping through the insulating coating 7a or by directly press-fitting the upright part 8b into the outer circumferential side surface 7b, and the cathode active material 10 is impregnated with an electrolyte.
Then, after placing the separator 12, the tablet-shaped anode active material 11 is placed, and finally, the cylindrical part 9b is moved around the outer periphery so that the anode can 9 is placed over the other open end side of the cylindrical body 7. It is assembled by being press-fitted into the side surface 7C via the insulating coating 7a or by shrink-fitting. Incidentally, in order to receive the outer peripheral portion of the separator 12, a ring member 16 made of nylon resin, fluororesin, etc., shown by the dotted line in FIG. 2, may be used as appropriate.

FIG. 6 is a vertical cross-sectional half-sectional view showing another embodiment of the flat battery of the present invention. In the middle of the inner surface of the cylinder 7, there is a separator 12 that divides the cathode active material 10 and the anode active material 11.
A stepped portion 7d is formed on which the outer circumferential portion 12a is placed. This stepped portion 7d prevents deformation of the separator 12 until the bipolar active material 11 is placed thereon, and also compresses and clamps the outer peripheral portion 12a of the separator 12 with the anode active material 11, thereby helping to prevent internal short circuits. Reference numerals 8.9 denote a cathode can and an anode can, respectively, which are the same as those shown in FIG.
The cylindrical portion 9b is fitted by press fitting or shrink fitting.

In addition, in FIGS. 2 and 3, which are embodiment diagrams of the present invention,
Although the cathode can 8 and the anode can 9 have been treated as separate members, they are completely the same parts. Further, although the cylinder 7 has been described as a metal material, in order to further increase the fitting force or reduce the radial wall thickness of the cylinder to increase the internal volume, l'Jz O), ZrO,,
It may also be made of a ceramic material such as Cry, Tie, or the like. As mentioned above, the flat-type battery produced by the present invention does not use a backing material similar to the conventional socket shown in Figure 1, so the ratio of internal volume to the total battery volume is Therefore, the battery discharge capacity can be greatly improved. In addition, as an insulating film coated on the surface of the cylinder, it has not only electrical insulation but also elasticity and water repellency, so the rich elasticity relieves pressure during fitting and creates gaps between fitting parts. In addition, the water repellency prevents the electrolyte from creeping up, thereby eliminating leakage. Furthermore, since the cylinder can be made of electrically insulating ceramic material, even if there are pinholes or tears in the Y-insulating coating, the cathode active material and anode active material can be connected through the cylinder. There is no possibility of deterioration of capacity due to internal short circuit. Furthermore, since the cathode can and the anode can can be made of the same common parts, it is possible to reduce the number of man-hours in processing and management, and it can be provided at a public cost.

As explained in detail above, according to the present invention, the battery volume can be used effectively, making it possible to increase the capacity, furthermore, achieving complete leakage resistance, and reducing costs by standardizing parts. This makes it possible to improve the reliability of such a flat battery.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional half-cut view of a conventional flat-type battery, FIG. 2 is a vertical cross-sectional half-cut view of a flat-type battery according to the present invention, and FIG. This is a half-section view of the longitudinal section. 7... Cylindrical body, 7a... Insulating coating, 7b, 7C...
Outer peripheral side surface, 7d...stepped portion, 8...cathode can, 8a...
・Bottomed part, 8b... Standing part, 9... Anode can, 9a.
... Upper plane, 9b... Cylindrical part, 10... Cathode active material, 11... Anode active material, 12... Separator, 12
a...Outer peripheral part.

Claims (1)

[Claims] (11) A cylindrical body whose surface is coated with an insulating film;
A cathode can has a mouth-like cross-sectional shape and its erected part is fitted to the outer circumferential side of one open end of the cylinder; A flat battery in which a cathode active material and a cathode active material, which are placed facing each other with a separator in between, are hermetically sealed with an anode can fitted on the outer circumferential surface of the open end side. (2) The flat battery according to claim 1, wherein the cylindrical body is made of a ceramic material whose surface is coated with an insulating film. (3) The flat battery according to claim 1, wherein the cathode can and the anode can are made of the same component. (4) The flat battery according to Claims 1 and 2, wherein the cylindrical body is provided with a stepped portion on which the outer peripheral portion of the separator is placed.