JPS60221967A - Thermal battery - Google Patents

Abstract

PURPOSE:To obtain a thermal battery whose self-discharge is eliminated and operation at high temperature is capable by using yttria fibers as heat-insulating material in a thermal battery in which lithium or lithium alloy is used as a negative eletrode. CONSTITUTION:A unit cell 1 consists of a three-layer pellet of a negative electrode, electrolyte, and a positive electrode. The unit cells are mutually stacked with heat generating agents 2. The negative electrode layer is composed of lighium-aluminium alloy, the electrolyte layer is composed of the mixture of LiCl-KCl eutectic salt and magnesia powder, and the positive electrode layer is mainly composed of iron disulfide. When current is instantly applied to an ignition terminal 6, an ignition unit 5 is ignited, then the heat generating agents 2 are burned to activate the battery. Yttria fibers are used as heat insulating material 7 which insulates heat of the battery. Yttria is stable to lithium alloy and the heat insulating ability is increased by forming it to fibrous form.

Description

[Detailed Description of the Invention] The present invention relates to a lithium-based thermal battery that uses lithium or a lithium alloy as a negative electrode, and provides a thermal battery that does not self-discharge during battery operation and is capable of high-temperature operation. .

Thermal batteries (using molten salt as electricity) cannot conduct current at room temperature, but when the parts used are heated to high temperatures, the electrolyte melts and exhibits extremely high conductivity. This makes it possible to discharge at a large current.

For this reason, thermal batteries do not self-discharge when unused and can be stored for long periods of time, making them excellent as highly reliable emergency alpine horn power sources.

A thermal battery holds a heating agent inside and ignites the heating agent to instantaneously heat the inside of the battery to an operating temperature and activate it. The power generation section of the battery is insulated and kept warm by insulation material, and is kept at the battery operating temperature for a long time.

Conventionally, asbestos, glass 111i1[I, ceramic fibers, and the like have been used as heat insulating materials for keeping the inside of a battery moisturized. Although such a heat insulating material is a lightweight and inexpensive heat-retaining material, it has been found that it is not suitable for lithium-based thermal batteries that use lithium or lithium alloy for the negative electrode. In other words, conventional insulation materials have silica (S102) and alumina (△1203) as their main components, but it is clear that these components easily react with lithium at high temperatures and are reduced. became. These reduced insulators generally turned black and became electrically conductive. When the insulation material became conductive, the battery self-discharged, reducing its discharge capacity, causing voltage fluctuations, and in severe cases, causing internal short circuits. Such a phenomenon has not been observed in conventional thermal batteries using calcium or magnesium as the negative electrode, and is thought to be due to the high activity of lithium.

The present invention is an attempt to improve such drawbacks, and is characterized by using iso1-ria (Y203) I film as a heat insulating material in a thermal battery using lithium or a lithium alloy as a negative electrode.

Ittria is stable against lithium and lithium alloys such as lithium-aluminum alloys, lithium-silicon alloys, and lithium-boron alloys. By making it into a 411If form such as woven cloth or felt, it can improve heat retention and serve as insulation for thermal batteries. It has become the perfect material.

Hereinafter, the embodiment will be explained.

FIG. 1 is a sectional view of the thermal battery of the present invention. In the figure, (
1) is a unit cell that constitutes a stacked battery.

Shiden II! ! Pellet (1) is composed of three layers: a negative electrode layer, an electrolyte layer, and a positive electrode layer, which are alternately laminated with exothermic agents (2). (3) is a negative terminal, and (4) is a positive terminal. (5) is an igniter, and when an instantaneous current is passed through the ignition terminal (6), the igniter (5) ignites, ignites the exothermic agent (2), and activates the battery. (7) is a heat insulating material that insulates and keeps the battery warm, and uses Ittria fiber. (
8) is a battery container that keeps the inside of the battery airtight.

Diameter 54n+m, thickness 1.05. A stacked battery was constructed by alternately stacking 16 unit cells made of +nm three-layer pellets and a heat generating agent made of a mixture of Fe and K CI O4.

The negative electrode layer of the unit cell is made of lithium-aluminum alloy 0.75
g. The electrolyte layer was composed of LI CI-K C1 eutectic salt and magnesium oxide powder mixture 2 (1. The positive electrode layer was composed of 1.5 g of a mixture whose main component was iron disulfide.

FIG. 2 shows the change in terminal voltage when battery A according to the present invention and conventional battery B were activated at an environmental temperature of 80° C. and discharged with a current of IOA.

Although thermal batteries can generally be used in a wide temperature range of -55°C to 80°C, comparisons were made at high temperatures in order to more clearly demonstrate the effects of the present invention.

Battery A according to the present invention uses ittria felt (
(manufactured by ZICAR PRODUCTS, USA) was used. Conventional battery B uses ceramic II Ilt as a heat insulating material.
This fiber flux (manufactured by Toshiba Monoflux Corporation) is used. In conventional battery B, an internal short circuit phenomenon was observed, and both discharge voltage and discharge capacity decreased. When the battery was disassembled after the discharge test, it was observed that the heat insulating material of conventional battery B had turned black at the part where it came into contact with the unit cell, and was partially melted. It was also observed that the discolored heat insulating material did not exhibit electrical conductivity. This is because the ceramic 111m was reduced by the lithium alloy of the negative electrode at high temperature, which caused an internal short circuit. Battery A according to the present invention had no self-discharge or internal short-circuit phenomenon, and no change in the ittria fiber used as a heat insulating material was observed.
1 By using ittria fiber as a heat insulating material as described above, it has become possible to obtain a stable thermal battery even at high temperatures. It should be noted that it is not necessary to use all the Ittria fibers as the heat insulating material, and the effect can be expected if it is used at least only in the portion that comes into contact with the unit cell.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a battery according to the present invention, and FIG. 2 is a discharge characteristic diagram showing a comparison between a battery according to the present invention and a conventional battery.

Claims (1)

[Claims] 1. Lithium or (bum alloy is used for the negative electrode,
A thermal battery characterized by using insulators as insulation materials.