JPH11126619A - Thermal cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain high activity of a thermal cell in a low temperature condition and to accomplish reduction in weight and size by arranging a heating device provided with a film heater and a thermostat on a cell case surface. SOLUTION: In a thermal cell, a film heater 6 and a thermostat 7 are arranged so as to cover the surface of a cell case 1 for heating the thermal cell. The film heater 6 is stuck to the cell case 1 directly/via a silicone rubber sheet by means of a silicone/epoxy group adhesive. As the thermostat 7, a thermostat, in which a heater circuit is turned on at about 20-30 deg.C and turned off at about 50 deg.C, is used. Therefore, the thermal cell is controlled to 20-+75 deg.C by means of the heater even when the cell is used over a wide temperature range from -55 deg.C to +75 deg.C, so that the cell is used with its active material maintained in a high activity condition. In addition, the cell is hardly increased in volume, so that compactification can be accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a thermal battery.

[0002]

2. Description of the Related Art A thermal battery is a battery in which a molten salt is used as an electrolyte. During storage, the electrolyte is a non-conductive solid salt and cannot supply power to the outside. By burning, the electrolyte is heated to be in a molten state with good conductivity, so that electric power can be supplied to the outside.

Such a thermal battery has the following features, and has been put to practical use as a power supply for a flying object or an emergency power supply.

(1) Storage for more than 10 years is possible.

(2) High-power discharge is possible because active materials having high activity such as calcium, magnesium and lithium can be used.

(3) Usable in a wide temperature range of -55 to + 75 ° C.

(4) It is resistant to vibration and shock.

As components of the thermal battery, the negative electrode is a lithium alloy, the positive electrode is iron disulfide, the electrolyte is a eutectic salt such as lithium chloride-potassium chloride, the heating element is iron / potassium perchlorate, and the heating material is zirconium / chromium. Barium acid or the like is used.

In the thermal design, the temperature of the negative electrode is set so that the negative electrode does not melt at the time of high temperature during use, and the reaction area and the active material are designed to exhibit the performance even at the lowest temperature during use under these temperature conditions. Is determined, and the amount of the heating element is determined based on the data.

Normally, the set temperature is set to around 520 ° C. when the maximum operating temperature is + 75 ° C. for the above-mentioned reason, and the value obtained by adding the design temperature to the maximum operating temperature is lower than the melting point of the negative electrode. .

[0011]

When a thermal battery is used for an aircraft, the temperature range is from -55 ° C to + 75 ° C and 1 ° C.
Since the temperature is as high as 30 ° C., if the design temperature is + 520 ° C., the operation will be at + 465 ° C. under low temperature conditions, the activity of the battery will decrease, and the reaction area of the battery must be large, and at the same time, a large amount of active material will be supplied. I needed to.

[0012]

The thermal battery of the present invention is characterized in that a heating device provided with a film heater and a thermostat is provided on the surface of a battery case. Further, a metal foil is used as a resistor of the film heater.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a thermal battery according to the present invention, a heating device having a film heater and a thermostat is installed on the surface of a battery case. Since the thermal battery is usually used in an emergency such as when power is lost, power can be supplied from the outside until just before use. Using this power source, the thermal battery is heated until immediately before use. By installing such a heating device, the temperature of the thermal battery can be made equal to normal temperature even under low temperature conditions, the activity of the thermal battery can be increased, and a small and lightweight thermal battery can be provided.

[0014]

FIG. 1 is an external perspective view showing an embodiment of a thermal battery according to the present invention, in which a film heater 6 and a thermostat 7 are mounted so as to cover the surface of a battery case 1 to heat the thermal battery. In the figure, 2 is a battery cover, 3 is an output terminal 4
Insulating glass for insulating the ignition terminal 5 from the battery cover 2 and leading it out of the battery cover 2, and reference numeral 8 denotes a conductor for connecting the film heater 6 to an external power supply.

The main body of the thermal battery is not different from the conventional one. The film heater 6 is bonded to the battery case 1 directly with a silicon-based or epoxy-based adhesive or via a silicon rubber sheet. Thermostat 7 is at 20 ° C
A type in which the heater circuit was turned on at about 30 ° C. and turned off at about 50 ° C. was used.

FIG. 2 is a plan view showing an example of the film heater 6, and FIG. 3 is an enlarged sectional view showing a part of the film heater. The film heater 6 uses a metal foil (stainless steel foil in this embodiment) as a resistor. The cover foil film is provided on the upper surface of the metal foil, and the base film is provided with an insulating film on the lower surface. Has a structure provided with an adhesive for adhering to the surface of the storage battery. In addition, both ends of the resistor have solder connection portions for connecting connection wires to an external power supply.

The thickness of the film heater is about 0.1 mm, which is very thin and flexible, so that it can be installed on a curved surface.
It has the characteristic that it hardly increases in volume.

[0018]

According to the present invention, the operating temperature of the battery is -5.
Even in a wide temperature range of 5 ° C. to + 75 ° C., the thermal battery is controlled at 20 ° C. to + 75 ° C. by the heater, so that the battery itself can be used with a high activity of the active material. Moreover,
Since the volume hardly increases, by adopting the present invention, the battery system φ50 mm × height 50 mm, mass 3
50g thermal battery, battery system φ40mm × height 50mm,
The size can be reduced to 280 g.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing one embodiment of a thermal battery of the present invention.

FIG. 2 is a plan view showing an example of a film heater.

FIG. 3 is an enlarged sectional view showing a part of the film heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery case 2 Battery cover 3 Insulating glass 4 Output terminal 5 Ignition terminal 6 Film heater 7 Thermostat 8 Conductor

Claims (2)

[Claims] 1. A thermal battery comprising a heating device provided with a film heater and a thermostat on the surface of a battery case. 2. The thermal battery according to claim 1, wherein the film heater uses a metal foil as a resistor.