JPH02284349A - organic electrolyte battery - Google Patents

Abstract

PURPOSE:To obtain an organic electrolytic battery of excellence in safety and reliability by using a polyolefin-group-resin thermally welded film previously provided with cutout portions to be sticked to a thin metal plate as a valve the hole of which is always blocked. CONSTITUTION:A thin metal plate 4a which is made of anti-corrosive metal such as aluminum, stainless steel and nickel or these alloy is sticked to a thermally welded film 4b previously provided with sewing cuts 8 to constitute a valve 4 the hole 3a of which is always blocked, and thermally adhered in an assembly sealing plate (B). With the assembly sealing plate (B) like this used, when the internal pressure of a battery rises, an operational valve 4 is broken under low pressure, and as anti-organic-electrolyte adhesive composition is used to perform thermal welding, a battery can be obtained which maintains air-tight sealing for a long period and has excellent liquid-leakage resistance and stable characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an organic electrolyte battery constructed using a light metal such as lithium as a negative electrode active material.

Conventional technology Organic electrolyte batteries that use light metals such as lithium and sodium as negative electrode active materials have high voltage, high energy density,
It has excellent long-term reliability, and demand for it has recently been increasing as a power source for memory backup power supplies, camera power supplies, etc. However, when used in this type of application, due to the structure of the battery, stable sealing and airtightness over a long period of time are required, and extremely highly airtight sealing has been required. For this reason, internal.

If charging was performed due to an 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.

For this reason, conventional measures have been taken as shown in (1) and (2) below.

(1) As shown in FIG. 5, a ring-shaped thin wall portion 1a is provided in a part of the battery container 1, so that the thin wall portion 1a of the battery container 1 ruptures before the internal pressure increases and reaches a dangerous state. to disperse the gas inside the battery to the outside.

(2) A thin metal plate, a thin sheet of synthetic resin or synthetic rubber, or a laminate film made by laminating a thin metal plate and a film of synthetic resin or synthetic rubber is placed in the battery assembly sealing plate as a sealing member, When the internal pressure rises, the expanded thin plate is broken with sharp breaking protrusions, allowing the gas inside the battery to escape to the outside.

Problem to be Solved by the Invention However, in the case of the above (1), when forming the thin wall portion 1a in the iron battery container 1 in such a structure, the thickness of the thin wall portion 1a must be 0.08~0.08 mm due to processing accuracy. The reality is that it can only be made as thin as 0.15 m+, and in this case there is a drawback that the explosion-proof function does not operate unless the internal pressure of the battery reaches a high pressure of 50 to 70 kg/crl. In the case of (2) above, if the structure uses a thin plate of elastic material such as synthetic rubber or synthetic resin, the thickness should be about 0.1 to 0.3 mm in order to achieve low pressure operability. In this case, synthetic rubbers and synthetic resins are extremely susceptible to atmospheric moisture permeation, making them particularly unsuitable for organic electrolyte batteries that dislike moisture. Because it has many characteristics, the operating pressure is not constant. In addition, a thin metal plate is ideal as a material with low moisture permeability, but considering low pressure operability, the thickness needs to be on the order of several μm, and such a thin plate is caulked to the assembly sealing plate. Inserting and fixing using this method was difficult in terms of airtight sealing.

If a laminate material is used in which a thin metal plate is laminated with a film of one synthetic resin and one synthetic rubber, the problems that would occur when a thin metal plate, two synthetic resins, and a synthetic rubber film are used alone are alleviated, but the explosion-proof In terms of functionality, the thickness of the synthetic resin 2 synthetic rubber is thinner and the elongation is greater (as a result, it takes longer to break, which increases the failure pressure and causes large variations in the failure pressure. Also, it has poor airtight sealing properties. It was also not sufficient in that respect.

Means for Solving the Problems The present invention solves the above problems by applying a thin metal plate made of a corrosion-resistant metal such as aluminum, stainless steel, or nickel, or an alloy thereof, to the surface of the film by forming perforations in advance. A heat-fusible film with a slit formed therein is bonded to the assembled sealing plate to form a valve that permanently closes the valve hole.

■ The assembled sealing plate is made by laminating the heat-fusible film with a heat-fusible film with a defective part of an appropriate shape in the area other than the contact area of the heat-fusible film as a valve that constantly closes the valve hole. It is thermally bonded to.

■ A heat-welded film containing an additive having a particle size smaller than the thickness of the heat-welded film is bonded to the assembled sealing plate to form a valve that constantly closes the valve hole.

Function: By using the assembled sealing plate with these configurations,
Even if the internal pressure of the battery increases, the operating valve will break at low pressure, and since it is heat-welded using an organic electrolyte-resistant adhesive composition, it can maintain airtightness for a long period of time.
It also has excellent leakage resistance and can provide a battery with stable battery characteristics.

Example Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 shows a cylindrical lithium battery using the assembled sealing plate of the present invention. It consists of the main material plus a conductive material and a binder. The negative electrode is configured in a spiral shape with a separator material (not shown) made of metallic lithium or microporous film interposed therebetween. In this element group, a single or mixed solvent such as 1,2-dimethoxyethane, dioxolane, or γ-butyrolactone is used as an electrolyte, and Li BF4. L
It is impregnated with a solution of iCe04 etc. as an electrolyte. Reference numeral 1 denotes a battery container having a current collector lead 2 made of metallic lithium, which is the negative electrode active material of the electrode plate group, welded to its inner surface by spot welding, and thus also serves as a negative electrode terminal. Preferably, the material of the case is stainless steel having an organic electrolyte resistance of about 0.3 mm or an iron case coated with anti-dip plating. Reference numeral B designates an assembled sealing plate in which a valve body 4 having a structure in which a thin metal plate 4a and a heat-fusible film 4b according to the present invention are bonded together is disposed inside. Its structure is such that a valve hole 3a is bored in the center of the inner bottom surface of the second horizontal part 3b, and a valve body 4 of the present invention is thermally bonded to the first horizontal part 3C so that the thin metal plate 4a is on the top surface. The lower case 3 is welded to the lower case 3, and the cap 5, which has a gas vent hole 5a in the convex portion 5b and whose peripheral edge 5c is formed into a flat shape, is molded inside the opening 3d of the lower case 3. The cap is bent and the peripheral edge of the cap and the metal surface of the valve body 4 are mechanically caulked and fixed. The lower case 3 is made of organic electrolyte-resistant stainless steel with a thickness of about 0.3 m, and the cap 5 is made of iron plated with dipping-resistant nickel and has a thickness of about 0.3 m. The configuration of the valve body 4 is the second
As shown in the figure, aluminum 4a (equivalent to Jl54160) with a thickness of 20 to 30 μm and aluminum 4a with a thickness of 30 to 30 μm are used.
This is a bonding material of the heat-fusible film 4b of the present invention, which is made of a heat-adhesive composition that is 50 μm resistant to electrolyte and has excellent metal adhesion, and the material of the film 4b is polyethylene, polypropylene, etc., which have excellent chemical resistance. It is a polyolefin resin. The aluminum 4a and the heat-fusible film 4b are thermally bonded together using a hot roller or static electricity.
They are integrated by electrostatic pressure bonding and pasting. Next, on the bottom surface of the lower case 3 of this sealing plate B, a current collecting lead 6 from the positive electrode active material of the electrode plate group A is integrated by spot welding, so that the sealing plate B also serves as a positive electrode terminal. Moreover, the assembly sealing plate B equipped with such a valve body is the power generating element group A.
The opening 1b of the metal case 1 containing the metal case 1 is hermetically sealed via an insulating backing 7 made of polyvinylidene chloride, which has low moisture permeability and electrolyte resistance, and polypropylene, which has high tensile strength. Next, the heat-fusible film 4b of the valve body 4
The detailed configuration of this section is described below. Figure 3 shows a strip-shaped heat-fusible film 4b with perforations 8 uniformly provided in advance, and this strip-shaped heat-fusible film laminated to a thin metal plate 4a and then punched out into a circular shape. It is used for FIG. 4 shows a belt-shaped heat-fusible film 4b.
An example of a product in which a heat-fusible film is laminated onto a thin metal plate 4a, with an appropriate cutout 9 provided except for the portion 4c that contacts the horizontal portion of the first stage of the lower case, and then punched out into a circular shape. It is. Or an organic solvent-resistant additive with a particle size smaller than the thickness of the heat-fusible film,
For example, 3 to 10 wt% of organic acids such as maleic acid, stearic acid, sebacic acid, or their salts are added to a polyolefin resin, and a heat-fusible film is laminated onto a thin metal plate to form a predetermined shape. It is used after being punched out. Next, regarding the effects of the present invention, each heat-fusible film 4b is laminated onto a thin aluminum plate 4a (equivalent to JIS 4160) having a thickness of 30μ±5μ, which is used as the valve body 4, and a sealing plate B is constructed. The failure pressure was measured for 100 pieces of each. The measurement method was as follows: The outer diameter of the sealing plate was 15.0 m, the height was 4.0 m+, and the valve hole was 3. Table 1 shows the results of measuring and comparing the pressure at the time of failure by feeding air from a cylinder into the valve hole to increase the pressure, with Ow* and the pressure receiving area of the valve body constant at 0.3 cnf. As the heat-fusible resin material, a polyethylene-based material having a thickness of 50μ±5μ was used.

(Left below) Other metal materials, such as those with a thickness of 5 to 10 mm, can be used as thin metal sheets.
μ nickel, 8-11μ thick stainless steel (SUS)
430.3(1) also showed the same results as in Table 1. In addition, although the product of the present invention (I [[) with a particle size of 50 μm or less, preferably 30 μm, containing 5 wt% of stearic acid is shown, other organic acids mentioned above, or their salts may be used in the range of 3 to 30 μm. If the amount added is 10 wt%, the results are similar to those shown in Table 1.

Effects of the Invention As is clear from the above, the valve body constructed according to the present invention has less variation in failure pressure, and the average value of failure pressure is also low (this means that the battery internal pressure increases). When the heat-fusible resin film of the valve body has uniform cuts such as perforations, or the presence of defects in the heat-fusible resin film, the elongation of aluminum, etc. Since the internal pressure is applied directly to the thin metal plate, it is possible to exhibit a low failure pressure with a small average value with little variation.Also, a predetermined amount of additives such as organic acids whose particle size is smaller than the film is added to the heat-fusible resin. This is because the elongation of the resin film can be reduced without affecting its adhesive strength.

Therefore, it is safe to use the valve body according to the present invention.

It is possible to provide an organic electrolyte battery with excellent reliability.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a battery using a sealing plate equipped with a valve body using a heat-fusible resin film according to the present invention, Fig. 2 is a schematic cross-sectional view showing the structure of the valve body, Figs. 3 and 4. 5 is an explanatory diagram illustrating the state of the heat-fusible resin film of the present invention in a band-like state before being laminated to a thin metal plate, and FIG. 5 is a sectional view of a battery equipped with a conventional safety valve device. 1...Battery container, 2.6...Lead piece, 3...Lower case, 4...Valve body, 4a
....Thin metal plate, 4b.. Heat-fusible resin film, 5.. Cap, 7.. Insulating backing, 8.. Cut. 9...
Defect part. Name of agent: Patent attorney Shigetaka Awano and 1 other person Fig. 1・-'1j 浬寥 3--Ichio γ-su 4b -- Masai [Nursing film constant voltage t1 detailed diagram

Claims (3)

[Claims] (1) An organic electrolyte battery that uses an organic solvent as an electrolyte, has a valve hole on the inner bottom surface of the lower case of the assembled sealing plate, and has a built-in valve body that closes the valve hole from the inside of the sealing plate. As a valve body that constantly closes the above valve hole, a thin metal plate is bonded to a heat-weldable film made of polyolefin resin with cutouts in advance. An organic electrolyte battery that is glued and secured by bending and caulking the open end of the lower case through a cap with gas vent holes. (2) The organic electrolyte battery according to claim 1, wherein the valve body that constantly closes the valve hole is made of a polyolefin-based valve having a defective part in an appropriate shape except for the part that contacts the inner bottom surface of the lower case. Using a heat-fusible film made of resin and a thin metal plate bonded together, the valve body is heat-bonded to the inner bottom surface of the lower case, and the open end of the lower case is bent through a cap with a gas vent hole. Organic electrolyte battery fixed with caulking. (3) The organic electrolyte battery according to claim 1, which is a polyolefin containing an organic solvent-resistant additive whose particle size is smaller than the thickness of the heat-fusible film, as a valve body that constantly closes the valve hole. The above-mentioned valve body is heat-bonded to the inner bottom surface of the lower case, and the open end of the lower case is bent and caulked via a cap having a gas vent hole. Fixed organic electrolyte battery.