JPS63121246A - Flat type battery - Google Patents

Abstract

PURPOSE:To keep insulating properties of a conductive film in its planar direction so as to prevent any accident due to short-circuit by making connection a positive electrode board a negative electrode board to leading wire terminals through an anisotropic conductive film. CONSTITUTION:To make connection of a flat type battery to leading wire terminals, the end part of the flat type battery, is inserted between a thermal contact bonding head 11 and its bearer 11', an anisotropic conductive film 10 is placed on the joining part of one side terminal board and one side leading wire terminal is placed thereon, and thereafter, the whole assembly is thermally pressed by using the terminal head 11. If the bearer 11' is also used as a thermal contact bonding head, both terminal boards of the battery and two leading wire terminals can be connected together at once. By the arrangement, many problems such as inconvenience of joint by conventional soldering, rupture of sealing point by electric welding and short-circuit accident caused by conductive adhesive are resolved and a state of joint with high reliability can be very simply obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a connection between a flat battery and an external lead terminal, and more specifically, relates to a connection between a flat battery and an external lead terminal. This invention relates to a flat battery that is free from electrical short-circuit accidents.

(Prior Art) In recent years, as electronic devices such as desktop computers and electronic wristwatches have become smaller and thinner, there has been an increasing demand for flat batteries as power sources for these devices. Among these, ultra-thin and highly reliable flat batteries with a thickness of 0.5111 mm or less are strongly desired for use in card-type electronic devices such as card-type calculators and IC cards.

Conventionally, as such a flat battery, one having a structure as shown in FIG. 1, for example, is known.

That is, in the figure, a negative electrode 1 and a positive electrode 2 are stacked with a separator 3 in between to form a power generation element. A frame-shaped insulating sealing body 4 is disposed surrounding the power generation element made of this laminate, and a negative electrode terminal plate 5 covers one end surface of the insulating sealing body 4 and the lower surface of the negative electrode sheet 1. Further, a positive electrode terminal plate 6 is tightly attached to cover the other end surface of the insulating sealing body 4 and the upper surface of the positive electrode 2, respectively.

In such a flat battery, the negative terminal plate.

A stainless steel sheet with a thickness of 0.02 to 0.05 layers is usually used for the positive terminal plate, and the heat-fusible resin for the sealing body is 1, for example, modified polypropylene, modified polyethylene, or methacrylic acid-ethylene. Copolymers, ionomer resins, and other materials having a heat fusion temperature of 150° C. or lower are used. By heat-sealing these elements, the power generation element is encapsulated throughout the battery.

By the way, in order to put the above-described flat battery into practical use, it is necessary to electrically connect the battery and the equipment in which it is installed. FIG. 1 shows a state in which the respective ends of the negative terminal plate 5 and the positive terminal plate 6 are slightly extended, and are connected to lead terminals 7 and 8 of an external device at the extended parts.

Conventionally, this connection is typically made by soldering, electric welding, or conductive adhesive.

(Problems to be Solved by the Invention) Connections by soldering have the following problems. That is, the stainless steel that constitutes the negative terminal plate and the positive terminal plate does not wet well with solder, and the connection between each terminal plate and the lead terminal is not highly reliable. To this end, efforts have been made to partially plate the surface of the connection part of each terminal board with nickel or tin to improve wettability with solder, but this complicates the assembly process and is difficult to manufacture industrially. I don't like it.

On the other hand, when connecting by electric welding, the high temperatures generated during welding create holes in each thin terminal plate, and in the worst case, the insulating sealing body melts, destroying the battery's sealing properties and causing leakage of electrolyte. Sometimes. Furthermore, in the case of conductive adhesives, there is a problem that this excess adhesive may hang around the terminal plate of the opposite pole in a string-like manner, causing conduction and reducing battery performance. there were.

An object of the present invention is to provide a flat battery manufactured using a novel connection method that solves the above-mentioned problems that occurred when connecting the flat battery and lead terminals.

[Structure of the Invention] (Means for Solving Problems) In order to connect the flat battery of the present invention and the lead terminal, a positive electrode is placed between the positive terminal plate and the negative terminal plate.

A flat battery with a structure that encapsulates a power generation element made of a separator and a negative electrode laminated in this order, and an insulating sealing body made of a frame-shaped heat-fusible resin that surrounds the power generation element. , when connecting to the lead terminal, the positive terminal plate, the negative terminal plate, and the lead terminal are connected via an anisotropic conductive film.

In the present invention, the flat battery to be joined to the lead terminal is a battery having a structure as exemplified in FIG.

The anisotropic conductive film used in the battery of the present invention is a polymer film that can be bonded by thermocompression, has conductivity in the thickness direction of the film, and insulation property in the plane direction of the film, and is made of thermoplastic resin (for example, SDR). This is a film in which, for example, carbon fibers are dispersed and arranged in the film thickness direction in the axial direction of the film (resin). Specifically, Sony
Examples include the cptooo series commercially available from Chemical Company.

When connecting the flat battery to the lead terminal, the end of the flat battery is inserted between the thermocompression bonding pad 11 and its pedestal 11', as illustrated in FIG.

An anisotropic conductive film 10 is placed on the joint part of one terminal plate (negative terminal plate 5 in the figure), and one lead terminal (lead terminal 7 in the figure) is placed on top of the anisotropic conductive film 10, and then the whole is heated. Hot pressure pressing may be performed using the pressure bonding head 11.

Note that if the pedestal 11' is also a thermocompression bonding head, it is also possible to connect both terminal plates of the battery and two lead terminals at once with one thermocompression press.

The hot press conditions include a temperature of 120 to 140°C and a press pressure of 20 to 30 kg/c+s2. Press time 5-10
seconds is preferred in that it provides a reliable connection.

(Embodiment of the invention) A Li foil with a thickness of 0.08 mm was used as the negative electrode, and a Li foil with a thickness of 0.22 mm made of fired MnO2, a conductive material, and a binder was used as the positive electrode.
The power generating element was constructed of a 0.12 mm thick polypropylene nonwoven fabric impregnated with a non-aqueous electrolyte as a separator. A methacrylic acid-ethylene copolymer was selected as the material for the insulating sealant.

5US with a thickness of 0.04 mm for the negative terminal plate and positive terminal plate.
A flat battery as shown in FIG. 1 was manufactured using zero or more elements using 304 plates.

An anisotropic conductive film (product name CP1030,
10 (thickness: 30 μm, manufactured by Sony Chemical Company) was placed thereon, and a lead terminal was further brought into contact therewith, and the whole was hot-pressed at a temperature of 130° C. and a press pressure of 25 kg/cta2 for about 10 seconds.

When the open circuit voltage and internal resistance of each of the 100 battery lead terminal connections obtained were examined, none of the above results were found.

For comparison, the flat battery described above was connected to lead terminals using a conventional electric welding method. When 100 of these were subjected to the same characteristic test as in the example, about 70% were found to have poor characteristics. When we investigated the defective products, we found that most of the battery terminal boards had holes and the insulating seals melted, destroying the battery sealing properties. Furthermore, even if the anisotropic conductive film in the flat battery according to the present invention protrudes from the connection point and comes into contact with a terminal plate of another polarity, the conductive film is insulating in the plane direction of the film, resulting in a short circuit. There were no occurrences. Therefore, it is possible to use a membrane having a wider dimension than the connection area, and the connection strength can also be improved.

[Effects of the Invention] As is clear from the above explanation, the battery of the present invention solves the problems of inconvenient connections by conventional soldering, problems of sealing failure during electric welding, and short circuit accidents caused by conductive adhesives. This solves the problem and makes it possible to establish a highly reliable connection extremely easily, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a state in which a flat battery and lead terminals are connected, and FIG. 2 is a diagram illustrating a state in which the battery of the present invention is manufactured. 1-Negative electrode 2-Positive electrode 3-Separator 4-Insulating sealing body 5-Negative terminal plate 6-Positive terminal plate 7.8-Lead terminal 1〇-Anisotropic conductive film 11-Thermocompression bonding head 11'-Second pedestal figure

Claims (1)

[Claims] A power generating element comprising a positive electrode, a separator and a negative electrode laminated in this order between a positive terminal plate and a negative terminal plate, and an insulating sealing body comprising a frame-shaped heat-fusible resin disposed surrounding the power generating element. When connecting a flat battery having a structure in which a battery is enclosed with a lead terminal, the positive terminal plate and the negative terminal plate are connected to the lead terminal via an anisotropic conductive film. shaped battery.