JPS6119055A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To improve the liquid leakage resistance of an organic electrolyte battery and easily make it small and thin by preparing the insulating gasket from a polypropylene material containing an inorganic filler such as mica. CONSTITUTION:An organic electrolyte battery is constituted of a battery case 1 formed by stamping an organic-electrolyte resistance stainless steel plate, a sealing plate 2 formed by stamping the same material as above, a negative active material 3 pressed and fixed to the stamped sealing plate 2, a positive current collector 4 made of an expanded titanium metal, a positive active material 5 principally composed of carbon fluoride and a separator 6 made of a nonwoven polypropylene fabric. In this battery, an insulating gasket 7 prepared by combining 100pts.wt. of a polypropylene with 20pts.wt. of mica with a particle diameter of 40mum is used. Consequently, the battery has improved liquid leakage resistance and can be easily made small and thin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to organic electrolyte cells, particularly to improvements in insulating packing for flat configurations.

Conventional Structure and Problems A flat organic electrolyte battery has a negative electrode active material made of a light metal such as lithium, and a positive electrode active material mainly made of carbon fluoride or manganese dioxide. It is constructed in a sealed manner using a plate and insulating packing. The electrolyte is propylene carbonate and 1
, 2-dimethoxyethane dissolved in lithium borofluoride, etc., and the insulating packing is
A polypropylene molded body with good chemical resistance is used so that it will not be contaminated by the organic electrolyte.

However, polypropylene has the following drawbacks.

(1) Polypropylene has low mechanical strength, especially tensile yield point strength and flexural modulus, and the opening of the battery case is caulked inward toward the sealing plate through the insulating packing to seal the power generation element of the battery. In this case, the amount of plastic deformation of the insulating packing is large, making it difficult to maintain good sealing performance. In addition, as batteries become smaller and thinner,
There was a problem in that the insulating packing plastically deformed after the battery was sealed protruded above the sealing plate which also served as the negative terminal plate, thereby preventing contact between the terminals of the battery-using equipment and the battery negative terminal plate.

3 bae.

(2) Polypropylene has a low heat distortion temperature, and when batteries are actually used, they are sometimes exposed to high temperatures, in which case the physical properties of the insulation packing become unstable.
There was also a risk that this would lead to deterioration of the battery's leakage resistance.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide an organic electrolyte battery that has good leakage resistance and can be easily made smaller and thinner.

Structure of the Invention According to the present invention, the insulating packing of an organic electrolyte battery is formed of polypropylene containing an inorganic filler such as mica.

This configuration has the following advantages.

(1) The insulating packing is made of a composite material of polypropylene and an inorganic filler that has good resistance to organic solvents, and is not susceptible to organic solvents.

(2) The tensile yield point strength and flexural modulus of the insulating packing are improved by two to three times compared to an insulating packing formed from polypropylene alone. As a result, the amount of plastic deformation during battery sealing is small, the sealing performance is good, and it is easy to prevent the insulating packing from protruding above the sealing plate even in a small and thin battery.

(3) The heat distortion temperature of insulation packing was determined by ASTM test method D.
648 under a load of 18.6 C/C, the heat distortion temperature is approximately 60°C higher than that of polypropylene alone, reaching approximately 120"C, and various physical properties are stable at the ambient temperature in which the battery is normally used. You can get a good insulation packing.

The explanatory diagram of the example shows a lithium-fluorocarbon organic electrolyte battery of the example. In the figure, 1 is a battery case punched out of an organic electrolyte-resistant stainless steel plate, 2 is a sealing plate punched out of the same material, and 3 is a punched lithium sheet.
The negative electrode active material crimped onto the sealing plate 2 is shown. Furthermore, 4 is a positive electrode current collector made of expanded metal made of titanium, 5 is a positive electrode active material mainly made of fluorocarbon, 6 is a separator made of polypropylene 67, -7 nonwoven fabric, and 7 is mica with a particle size of 40 μm at a weight ratio of 20. % of polypropylene. The electrolyte contains propylene carbonate and 1.
Lithium borofluoride was dissolved at 1 mol/L in a mixed solvent with 2-dimethoxyethane.

Battery BR1a16 with the above configuration (diameter 16B, height 1.6
The table shows a comparison of various properties between A and B, which uses a conventional insulating packing molded only from polypropylene.

h is the amount of protrusion of the sealing plate from the upper end surface of the insulation packing shown in the figure. The number of leaking batteries is -1 for 1 hour at 60"C.
A heat shock of 1 hour at 0''C was applied to the batteries for 360 cycles, and the number of leaking batteries was visually confirmed for leakage every 120 cycles.

Each test was performed with n=20.

6 B/Effects of the Invention As is clear from the above, according to the present invention, it is possible to obtain an organic electrolyte battery that has improved leakage resistance and further allows easy terminal connection with equipment using the battery.

[Brief explanation of the drawing]

The figure is a half-sectional view showing a battery according to an embodiment of the present invention. 1...Battery case, 2...Sealing plate, 3
...Negative electrode active material, 5... Positive electrode active material,
6... Separator, 7... Insulating packing.

Claims (1)

[Claims] An organic electrolyte battery in which a negative electrode using a light metal as an active material, a positive electrode, and an organic electrolyte are sealed by a battery case that also serves as a positive terminal, a sealing plate that also serves as a negative terminal, and insulating packing interposed between the battery case and the sealing plate. An organic electrolyte battery, wherein the insulating packing is made of polypropylene mixed with an inorganic filler.