JPH0322349A - Organic electrolyte battery and manufacture of sealing plate thereof - Google Patents

Abstract

PURPOSE:To reduce the contact resistance of a sealing plate and improve the leakage resistance and mass productivity by forming a valve body with a composite material arranged with a heat adhesive resin film on both faces of a metal thin plate. CONSTITUTION:A heat adhesive resin film 3a is arranged on both faces of the metal thin plate 3b of a valve body 3 material to form a three-layer structure, a metal plate 4 with a hole at the center is mounted on the valve body 3, the valve body 3 is heated by a heating jig from the above of the metal plate 4, and the heat adhesive resin film 3a is melted and heat-stuck. The periphery rising section 1b of a dish-shaped sealing plate 1 is folded inward with a press or the like and pressed and pinched, and a terminal cap 2 is mounted on the periphery rising section 1b of the dish-shaped sealing plate 1. The sealing plate 1 with very low contact resistance can be constituted, and the leakage resistance and mass productivity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an organic electrolyte battery using a light metal such as lithium as a negative electrode active material, and a method for manufacturing a sealing plate thereof.

BACKGROUND OF THE INVENTION In recent years, electronics such as ICs and LSIs have made remarkable progress, and electronic precision equipment that uses these devices now requires only an extremely weak current of about several microamperes. In addition, primary batteries used as power sources for these devices are also required to be small and lightweight, have high energy density, and have long-term reliability. A battery that meets these requirements uses metallic lithium or a lithium-based alloy such as lithium-aluminum (Li-Ae) alloy as the negative electrode active material, and an aprotic high dielectric constant, low viscosity non-aqueous electrolyte as the electrolyte. There are organic electrolyte batteries that use metal oxides such as manganese dioxide, oxidized steel, or graphite fluoride as positive electrode active materials.If these batteries are to be operated for a long period of time, there are certain issues in the battery design. Stable airtightness and airtightness are required, and the seal is extremely airtight.

Therefore, if the battery were to be charged due to an internal short circuit, external short circuit, or leakage current, gas would be generated inside the battery, and if the internal pressure of the battery rose abnormally, the battery would explode, which was extremely dangerous. . Therefore, until now, the structure of the sealing plate B as shown in FIG. 3 has been adopted. In Figure 3, l
is a dish-shaped sealing plate with a valve hole 1a on its inner bottom surface, and the inner surface has a cutting edge 2a provided on the terminal cap 2, which swells as the internal pressure of the battery increases, or a heat shield that is naturally destroyed by gas pressure. A valve body 3 made of a laminated film of an adhesive resin film 3a and a thin metal plate 3b was arranged. Next, the manufacturing process of the valve body will be described. Step 1: A step of inserting and placing the valve body 3 on the inner bottom surface of the dish-shaped sealing plate 2 with the heat-adhesive resin film 3a facing downward.

Step 2: Pressing the valve body 3 against the inner bottom surface 1c of the dish-shaped sealing plate with a jig heated above the melting point temperature of the thermoadhesive resin film, and adhesively fixing the valve body to the inner bottom face of the dish-shaped sealing plate. .

Step 3 Step of inserting and placing the terminal cap 2 on the upper surface of the valve body 3.

Step 4: A step of bending the peripheral edge rising portion 1b of the dish-shaped sealing plate 1 inward and pressing and fixing the peripheral edge flat portion 2b of the terminal cap 2.

The explosion-proof sealing plate was constructed by the process described above.

Problems to be Solved by the Invention When preparing a sealing plate using the method described above, in step 2, the heat-adhesive resin film is heated to a temperature higher than the melting point of the heat-adhesive resin film to form a dish-shaped sealing plate. When pressed against the inner bottom surface of the valve body, the molten thermoadhesive resin film may ooze out onto the inner peripheral side surface 1d of the rising peripheral edge of the dish-shaped sealing plate, or onto the upper surface of the thin metal plate of the valve body material. there were. If an explosion-proof sealing plate is constructed according to step 3.4 under such conditions, a layer or shape of an insulating resin film will be interposed between the dish-shaped sealing plate and the terminal cap, which will also serve as a battery terminal. The resistance value (more specifically, the contact resistance value) of the sealing plate becomes high, and the current value that can be taken out when an electric circuit is formed becomes small, which has a negative effect on the equipment used.

Furthermore, if the heat-adhesive resin film oozes out during melting in step 3, it may adhere to the heating jig, which is inconvenient from the viewpoint of productivity.

Furthermore, in the case where a heat-adhesive resin film is not used as the valve body material in order to eliminate such problems, the built-in electrolytic solution has the disadvantage of extremely easily leaking into the battery terminal portion.

Means for Solving the Problems The present invention relates to a purchasing method and a manufacturing method that solves the above-mentioned problems. Specifically, a three-layer structure is used in which a heat-adhesive resin film is placed on both sides of a thin metal plate as the valve body material, and a metal plate with a hole in the center is placed on the top surface of the valve body. Then, the valve body is heated from the top surface of the metal plate using a heating jig to melt and thermally bond the thermoadhesive resin film, and then the raised peripheral edge of the dish-shaped sealing plate is bent inward using a press or the like. The process involves pressing and holding the terminal cap and placing the terminal cap on the upper surface of the rising edge of the dish-shaped sealing plate.

Effect: By using this configuration and manufacturing method,
It is possible to provide an explosion-proof sealing plate with low contact resistance, excellent leakage resistance, and mass productivity.

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to FIG. A
1 is a sealing plate equipped with an explosion-proof mechanism according to the present invention, which includes a dish-shaped sealing plate 1 having a valve hole 1a on the bottom surface of a protrusion 1d protruding toward the battery container side, and a first stage of the dish-shaped sealing plate. Horizontal periphery I
A disc-shaped valve body 3 is placed on C, a reinforcing plate 4 with a hole 4a in the center is placed on the upper surface of the valve body 3, and the peripheral rising portion 1b of the dish-shaped sealing plate is turned inward. By bending, the valve body 3 and reinforcing plate 4 are held in pressure contact with the first horizontal circumferential edge of the dish-shaped sealing plate. Therefore, the valve body 3 always closes the valve hole 1a of the dish-shaped sealing plate. A terminal cap 2 consisting of a convex portion 2c having a cutting edge 2a on the inner bottom surface and a horizontal flat portion 2b is placed on the upper surface of the peripheral edge rising portion 1b of the dish-shaped sealing plate. Note that the applicable material for the reinforcing plate 4 is a plate thickness of 0.
The valve body 3 is made of a corrosion-resistant metal material such as stainless steel or nickel plate with a thickness of about 1 to 0.3 m/m.
As shown in the figure, a thin metal plate 3b made of aluminum with a thickness of 10 to 30 μm has a thickness of 30 to 50 μm on both sides 3a.
It is composed of a three-layer lamination film 3a in which heat-adhesive polykylefin resins having excellent organic solvent resistance such as polyethylene and polypropylene are laminated together. These valve bodies have a failure pressure of 20 to 40 kg/cnt.

5 is a battery case containing a positive electrode, a negative electrode active material, and an organic electrolyte power generation element; 6 is a battery case containing a positive electrode active material of fluoride and metal oxide in a sheet form, and a metal lithium sheet as a negative electrode active material with a separator material. In the electrode group wound through the active material, each active material is connected to the inner bottom surface of the battery case 5 or the sealing plate A by a conductive lead piece 7. Reference numeral 8 is an insulating packing attached to the peripheral edge of the sealing plate A, which insulates the two electrodes of the battery, prevents electrical connection between the terminal cap and the dish-shaped sealing plate, and prevents leakage of the internal electrolyte.

Next, the method of constructing the sealing plate of the present invention will be explained. In step 1, the valve body 3 of the present invention is inserted and placed on the inner bottom surface of the dish-shaped date sealing plate 1. In step 2, the reinforcing plate 4 is inserted into the valve body. In the step of inserting and placing on the top surface, step 3, the top surface of the reinforcing plate is pressed with a jig moistened to a temperature higher than the melting point of the heat-adhesive resin film to melt the heat-adhesive film, thereby forming the first stage of the dish-shaped sealing plate. , and the lower surface 4 of the reinforcing plate 4}
) are bonded together with a heat-adhesive film, Step 4 is a step of bending the rising peripheral edge portion 1b of the dish-shaped sealing plate 1 inward and fixing the reinforcing plate 4 by pressure, and Step 5 is a step of bonding the reinforcing plate 4 into one piece. This process consists of a step of fitting the object into an annular insulating packing having a substantially L-shaped cross section, and a step of fitting and placing a terminal cap on the top surface of the shaped object in step 4 in step 6.

Next, the sealing plate according to the present invention and the sealing plate of the conventional structure were each placed in 5 pieces.
The battery is constructed with 00 pieces of power generating elements not housed, and the battery case is electrically connected to the dish-shaped sealing plate with a conductive lead piece, and the resistance between the terminal cap and the battery case is reduced. The measured results are shown in Table 1. Furthermore, Table 2 shows the number of electrolyte leaks from the battery terminal surface when the battery was constructed with the power generation element housed and stored in a high temperature atmosphere of 85°C. The battery size is 17+++n+ in diameter.
A manganese dioxide lithium battery with a height of 34M and a capacitance of 1300mAh was used.

(Margin below) Table 1 Table 2 Effects of the Invention As is clear from the above tables, the method of the present invention using the sealing plate has no insulation in the contact area between the terminal cap and the dish-shaped sealing plate. The interposition of the heat-adhesive resin that forms the body is completely prevented, and the contact between the metal terminal cap and the plate-shaped terminal board is maintained by the strong compressive pressure of the insulating packing, resulting in a seal with extremely low contact resistance. Boards can be configured. In addition, since the valve body is firmly heat-bonded at two places: the inner bottom periphery of the dish-shaped sealing plate and the bottom surface of the reinforcing plate, it is possible to achieve a highly airtight sealing state in terms of leakage resistance, and also to facilitate mass production. It is excellent.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a battery using the sealing plate obtained by the present invention, Fig. 2 is a cross-sectional view of the valve body material of the present invention, and Fig. 3 is a cross-sectional view of a battery using a conventional sealing plate. be. 1... Dish-shaped sealing plate, 2... Terminal cap, 2a... Cutting blade, 3... Valve body, 3a
...Thermoadhesive resin film, 3b...
Thin metal plate, 4... Reinforcement plate, 5... Battery case, 6... Electrode group, 7... Lead piece, 8... Insulating packing, A. B...
・Sealing board.

Claims (1)

[Claims] (1) A valve that has a power generation element consisting of a positive electrode, a light metal negative electrode, and an organic electrolyte, has a valve hole in the bottom of the dish-shaped sealing plate that protrudes toward the battery container, and closes this valve hole from the inside of the sealing plate. A dish-shaped sealing plate fixed by caulking the peripheral rising part of the dish-shaped sealing plate inward through a reinforcing plate on a ring whose body is disposed on the upper surface of the valve body, and a peripheral rising part of the dish-shaped sealing plate. An organic electrolyte battery is provided with a terminal cap having a protruding cutting edge facing the valve body on the upper surface thereof, the valve body being a composite material having heat-adhesive resin films arranged on both sides of a thin metal plate. An organic electrolyte battery characterized by: 2. A method for manufacturing a sealing plate for an organic electrolyte battery according to claim 1, comprising: inserting a valve element into the inner bottom surface of the dish-shaped sealing plate; inserting a reinforcing plate into the upper surface of the valve element; A process of pressing and heating the reinforcing plate with a heated jig from the top surface of the reinforcing plate, a process of bending the rising peripheral edge of the dish-shaped sealing plate inward to form it, and packing the molded product from the above process into insulating packing. A method for producing a sealing plate for an organic electrolyte battery, which comprises a step of fitting and a step of fitting a terminal cap onto the upper surface of a rising peripheral edge of a molded body.