JPS58111255A - Flat battery - Google Patents

Abstract

PURPOSE:To make the ratio of the internal volume to the entire volume of a thin battery large, increase the electric-discharge capacity of the battery, and prevent any liquid leakage of the battery completely by making the bottom surface of a negative terminal in contact with a positive active material through a separator. CONSTITUTION:The entire surface of a can 8 made of a metallic member is coated with a fluorine-system film 8a. The lower opening part of the can 8 is attached around a positive terminal 7 made of a metallic member. A negative terminal 9 made of a metallic member is provided with an annular caulking part 9a in its upper part, and the top surface and the side surface of the part 9a are coated with a fluorine-system film 9b. A separator 13 separates a positive active material 11 and a negative active material 12, which is impregnated with electrolyte, from one another so as to prevent any electric short-circuit. The bottom surface 9d of the negative terminal 9 touches the upper surface of the positive material 11 through the separator 13. By the means mentioned above, the ratio of the internal volum to the entire volume of the battery is made large, the electric-discharge capacity is increased, and any liquid leakage can be prevented.

Description

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

An example of a conventional flat type battery of this type will be explained with reference to a longitudinal cross-sectional half-sectional view shown in FIG.

1 is a cup-shaped anode can made of a metal material, 2 is a cap-shaped cathode can made of a metal material, and parent 3 is an anode can 1
This gasket is made of an insulating material and is provided between the anode can 20 and the cathode can 20 and the loop portion 2J, and is compressed and held by crimping the periphery of the upper opening 1m of the anode can 1 inward.

The battery case of the conventional flat battery shown in FIG. A substance 5 is separated and enclosed by a separator 6.

In this conventional flat cell sealing structure, the compressive reaction force of the gasket 3 causes the gasket 3 to connect to the anode can 1 and the cathode can 2.
Because it has a structure that prevents liquid leakage by bringing the parts into close contact with each other,
It was necessary to increase the thickness of the gasket 3 and increase the compression reaction force of the gasket 3. Therefore, the ratio of the volume occupied by the gasket 3 to the total battery volume is extremely large.
In order to increase the discharge capacity, it is necessary to increase the total volume of the battery when the composition of the contents is the same.

Furthermore, if the amount of compression of the gasket 3 is increased in order to improve leakage resistance, the force that compresses the gasket 3 causes the cathode can curled portion 2a to move inward, increasing the internal pressure of the battery can and causing the gasket 3 to become compressed. This increases the creep deterioration rate and is one of the causes of leakage.

In order to eliminate the drawbacks of the conventional technology, the present invention forms a battery case with a can whose surface is coated with an insulating film and an electrically conductive cathode terminal and an anode terminal. The object of the present invention is to provide a battery that increases the discharge capacity by increasing the ratio and completely prevents leakage.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 2 is a longitudinal cross-sectional half-sectional view of a flat battery according to the present invention. 7 is an anode terminal such as a metal material.

8 is made of a metal material and has a fluorine-based coating 8a on its entire surface.
The anode terminal 7 is fixed in the lower opening hole and is joined with a joining member 10.

9 forms an annular caulking part 9a on the upper part, and the caulking part 9
The cathode terminal is made of a metal material with a 9bt fluorine-based film coated on the surface and side surfaces of a. 11 is a tablet-shaped anode active material, and 12 is a cathode active material impregnated with an electrolytic solution. Note that the thickness of the coatings 8a and 9b is exaggerated in the drawing.

A separator 13 separates the anode active material 11 and the cathode active material 12 to prevent electrical short circuits.

The thickness e from the stepped portion 9C to the bottom surface 9d of the cathode terminal 9 described above is set to be equal to the distance from the inner surface 8b of the can 8 to the stepped portion 8C, so that the bottom surface 9d of the cathode terminal 9 is It is in contact with the upper surface of the anode active material 11 via the seventh palatator 13 .

In the flat battery formed as described above, the can 8 and the cathode terminal 9 are crimped together as parts, and the cathode active material 12
, the separator 13, and the anode active material 11, and then the anode terminal 7 can be attached to the can 8 without applying pressure to the contents, and the can 8 can be sealed with the joining member 10. . Therefore, it is possible to prevent an increase in internal pressure, which is one of the causes of leakage, and because it does not use anything similar to a conventional gasket, it is possible to increase the ratio of internal volume to total battery volume number 2. can.

In particular, the bottom surface 9d of the cathode terminal 9 in the present invention is in contact with the hard tablet-shaped anode active material 11 via the separator 13, so that pressing force due to contact with an external terminal etc. is applied to the top surface of the cathode terminal 9. However, the cathode terminal 9 is sandwiched between solid objects, and the annular caulking part 9 is caused by external force.
This will not cause loosening or deformation of a.

In this way, since the bonding force between the cathode terminal 9 and the can 8 does not decrease due to electrical contact pressure, the leakage resistance does not deteriorate even after long-term use or repeated attachment and detachment, and the initial leakage resistance is maintained. can do. Further, as shown in FIG. 3, by cutting a part of the portion 9e of the cathode terminal 9 housed inside the can 8, the capacity of the cathode active material 12 can be increased.

Furthermore, as shown in FIG. 4, by reducing the diameter of the portion 9f of the cathode terminal 9 below the stepped portion 9C, the capacity of the cathode active material can be further increased.

In addition, since the surface fluorine coating 8a of the can 8 and the side fluorine coating 9b of the cathode terminal 9 are crimped together, electrical conduction between the two parts can be completely prevented, and the coating has rich elasticity. Due to its strength and water repellency, it is possible to eliminate the gap between the two wave membranes, prevent the electrolyte from creeping up, and eliminate liquid leakage.

As the fluorine-based coatings 8a and 9b, tetrafluoroethylene (trade name: Polyflon) and trifluorochloroethylene (trade name: Guiflon) are suitable; Materials other than fluorine-based materials (for example, silicone-based, epoxy-based, etc.) may be used as long as they have good properties.

Furthermore, if a sealant such as tar or silicone grease is interposed between the non-fluorine coating 8a on the can surface and the fluorine coating 9b on the side of the cathode terminal, the leakage resistance can be further improved. .

In addition, by providing tapers in the anode terminal 7, can 8, and Q'4E attachment part 8b and snap-fitting them, assembly work can be performed quickly, and evaporation of the liquid and incorporation of foreign substances such as dust can be prevented. Further, since the anode terminal 7 is fixed to the can 8, leakage of liquid can be prevented until the can is sealed with the joining member 10, and the workability of the sealing work can also be improved.

Note that the sealing with the joining member IO may be performed by welding using a laser or the like.

As detailed above, according to the present invention, the battery volume can be used effectively, the capacity can be increased, and leakage resistance can be completely overcome, workability is improved, and such The reliability of the flat battery can be improved and a stable flat battery can be provided.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional half-mounted view showing an example of a conventional flat battery.
FIG. 2 is a longitudinal cross-sectional half-sectional view of the flat battery of the present invention, and FIGS. 3 and 4 are diagrams showing other embodiments of the cathode terminal. 7... Anode terminal, 8... Can. 8C...Stepped portion, 9...Cathode terminal. 9d...Bottom surface of cathode terminal, 4.11...Anode active material 5, 12-...-Cathode active material, 6.13Φ・Dispute・7 Palator No. 1112 Proceedings Amendment Book 1, Incident Display Showa 1956 Patent Application No. 208874 2, Title of the invention: Flat battery 3, Person making the amendment Telephone: 0555-3-1231 Voluntary 6, "Detailed description of the invention" column 7 of the specification to be amended, On page 4, line 9 of the description of contents, the phrase ``thickness θ'' is corrected to ``thickness l''.

Claims (1)

[Claims] A cathode active material, an anode active material, and an electrolyte are contained in a can whose surface is coated with a coating agent and an anode terminal sandwiching a separator, and the bottom surface of the cathode terminal is passed through the sehalator to the anode terminal. A flat battery characterized by being brought into contact with an anode active material.