JPH10172582A - Thermal cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quicken activation when a cell is used, and enhance heating and heat radiating efficiencies by housing the specified cell constituting components fitting to the metal case in a cylindrical sealed metal case having a hollow part passing through in the axis direction. SOLUTION: A metal case 10 of a thermal cell is formed by welding an upper surface part 13 and a bottom surface part 14 for sealing the upper and lower parts of two concentric cylinders having different diameters and a space formed between the two cylinders. The case 10 has a hollow part 15 passing through up and down in the center. The surface area on the outside of the case 10 is increased, and heating and heat radiation of each unit cell 1 are uniformly, rapidly performed. A negative terminal 16a and a positive terminal 16b are airtightly fixed to the upper surface part 13 of the case 10 through an insulator 17, and a stacked body of the unit cells 1 is housed in the case 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal battery activated by external heat.

[0002]

2. Description of the Related Art A thermal battery uses a molten salt, which is solid at normal temperature, as an electrolyte.
This is a type of high-temperature battery that can generate power by being heated to ° C. to be in a molten state. This high-temperature battery conventionally stores an igniter having a heating agent and an igniting agent together with a power generating element in a battery case, and activates the igniting device when using the battery to ignite the igniting agent and burn the exothermic agent. ,
The battery was activated. Once activated, the high-temperature battery of this form cannot be reused because the exothermic agent burns out once activated.

[0003] Therefore, there has been proposed a battery in which a heat-generating agent or the like is removed and a battery is heated by an external heat source when used. Since the battery of this mode can generate power as long as the battery active material is present, it can be activated and used as many times as necessary. Since a high-temperature battery is activated by heating to a high temperature, it is extremely stable for normal storage and has high reliability. Therefore, it is useful as a power supply for various flying objects, emergency power supplies, and control devices in space satellites.

[0004]

In the case of a thermal battery heated by an external heat source, it is desirable to use a large amount of a battery active material so that intermittent discharge can be repeated. However, when the amount of the active material is increased, there is a problem that the heating efficiency when heating from the outside is poor, and it takes time for activation. In particular, with this type of thermal battery, it is common practice to check battery performance for safety when reusing it. Further, in the case of repeated use, stable heating performance cannot be obtained unless heating and heat radiation are performed uniformly. Therefore, there is a demand for a thermal battery having good heating and heat radiation efficiency. In view of the above, an object of the present invention is to provide a heat battery of an external heating system which can be quickly activated when using a battery and has good heating and heat radiation efficiency.

[0005]

SUMMARY OF THE INVENTION A thermal battery according to the present invention has a cylindrical sealed metal case having a positive electrode terminal and a negative electrode terminal and having at least one hollow portion penetrating in the axial direction. A unit cell stack that is stacked and housed in the axial direction and has a cavity corresponding to the cavity, an insulating layer that insulates the metal case and the unit cell stack, and a positive electrode terminal of the unit cell stack. The thermal battery according to the present invention further includes a lead for connecting the negative terminal to the positive terminal and the negative terminal of the metal case.
A metal case provided with a positive electrode terminal and a negative electrode terminal, which is formed of an upper surface portion and a lower surface portion that seal the upper and lower portions of a space formed between two cylindrical bodies, and is stacked and housed in the space,
A unit cell stack having a cavity in the center, an insulating layer that insulates the metal case from the unit cell stack, and a lead that connects the positive terminal and the negative terminal of the unit cell stack to the positive terminal and the negative terminal of the metal case Is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the thermal battery of the present invention, since the cavity is provided in the case so as to penetrate the unit cell stack as described above, the surface area outside the case increases, and therefore, the heating of each unit In addition, heat can be uniformly and quickly dissipated. If there are a plurality of the hollow portions, the heating and heat radiation efficiency of the unit cell are further improved. However, since the configuration of the battery becomes complicated, it is practically preferable to use only one cavity and to make the case cylindrical.

The thermal battery of the present invention is activated by being heated by an external heat source. Since no heating mechanism is provided inside the battery, intermittent discharge can be performed when necessary. Also,
By heating to a temperature lower than the melting point of the electrolyte, for example, about 300 ° C., the output of the battery can be confirmed. For this reason, the reliability of the battery is improved. In a conventional thermal battery having a built-in exothermic agent, at such a temperature, the exothermic agent may be burned, and the battery may be activated.
Further, since the heat battery of the present invention does not include a heating agent or the like, if the battery capacity is the same as that of the conventional heating agent built-in type, the size of the battery is about half. Furthermore, the presence of the hollow portion increases the area of the outer surface of the battery, enables uniform heating and cooling, and enables mass production of thermal batteries without variation in discharge performance.

[0008]

Embodiments of the present invention will be described below. << Embodiment 1 >> FIG. 1 shows a configuration of a thermal battery of the present embodiment.
In FIG. 1, reference numeral 10 denotes a metal case. The metal case 10 is formed by welding two concentric cylinders 11 and 12 having different diameters, and an upper surface portion 13 and a bottom surface portion 14 which seal the upper and lower portions of a space formed between the two cylinders. . The metal case 10 has a hollow portion 15 vertically penetrating at the center thereof. A negative electrode terminal 16a and a positive electrode terminal 16b are hermetically attached to the upper surface portion 13 of the case 10 by a glass insulator 17. Further, the laminate of the unit cells 1 is housed in the case. An insulating material 9 made of a fiber containing alumina as a main component is inserted between the unit cell stack and the case. The unit cells 1 are connected in series, and the positive terminal thereof is connected to the positive terminal 16b of the case 10 by a lead piece 8b.
Further, the negative electrode terminal of the unit cell stack is connected to the negative electrode terminal 16a of the case by a lead piece 8a.

FIG. 2 shows the structure of the unit cell 1. For the negative electrode, after inserting the lithium sheet 3 into the iron cup 2, inserting the iron powder 4, forming and caulking the end of the cup inward, and then sandwiching the hot plate at 550 ° C. to melt the lithium and form the iron powder It is made by impregnating the body. The electrolyte layer 5
It is formed by adsorbing a eutectic salt of potassium chloride and lithium chloride on a magnesium oxide powder as an inorganic adsorbent, and the mixing ratio between the electrolyte and the adsorbent is 1: 1 by weight. The positive electrode is formed by mixing the above-mentioned electrolyte and inorganic adsorbent with iron disulfide as an active material, and the mixing ratio between the active material and the electrolyte is 7: 3 by weight. Reference numeral 7 denotes a positive electrode current collector made of an iron plate.

The unit cell 1 is manufactured as follows. That is, the above-mentioned negative electrode is inserted into a jig, a hole is drilled in a predetermined size in the center, the hole is inserted into a forming jig having the same hole shape, an electrolyte is put therein, and the first molding is performed. The perforated current collector 7 is put in and secondary molded. Thus, the unit cell 1 having the hollow portion a at the center is manufactured.

FIG. 3 shows a jig for combining the unit cell stacks, and FIG. 4 shows a state in which the unit cell stacks are combined. The jig 18 includes a disk 19 and a column 20 protruding from the center thereof. To construct the unit cell stack, first, an insulating material is laid on the disk 19, and the unit cell 1 is placed on the insulating material.
Are stacked so that the column 20 is located at the center of the hollow portion a. Then, the insulating material 9 is filled in the cavity a of the unit cell, and the insulating material 9 is put on the outer periphery and the upper surface of the unit cell stack. On the other hand, the case 10 is prepared in a state where the upper part before the upper surface part 13 is welded is opened, and the unit cell stack taken out from the jig 18 is inserted into the case together with the insulating material,
After welding the terminals 16a and 16b and the lead pieces 8a and 8b, the upper surface portion 13 is welded to the opening of the case and hermetically sealed.
In this way, thirty unit cells 1 were laminated to produce a thermal battery having an outer diameter of 50 mm, a height of 100 mm, and a cavity diameter of 15 mm.

FIG. 5 shows the results of measuring the open-circuit voltage of the thermal battery from the time when the thermal battery was inserted into a thermostat at 400 ° C. As is clear from FIG. 5, the thermal battery A of the example started up quickly, and started up in about 3 minutes. On the other hand, the thermal battery B of the comparative example having no hollow portion in the battery case required about 10 minutes from when it was inserted into the thermostat until it reached the predetermined voltage. FIG. 6 shows a comparison of the voltage stability of these thermal batteries, and it can be seen that thermal battery A of the example exhibits extremely stable performance. The data shown in FIGS. 5 and 6 are the average values measured for five batteries.

[0013]

As described above, according to the present invention, it is possible to obtain an external heating type thermal battery which can be quickly activated at the time of use and has good heating and heat radiation efficiency.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a thermal battery according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of the thermal battery with a part of a unit cell cut away.

FIG. 3 is a perspective view of a jig for assembling the unit cell stack.

FIG. 4 is a perspective view of the unit cell stack during assembly.

FIG. 5 is a diagram comparing a rise in voltage at the time of battery startup of the thermal battery and a thermal battery of a comparative example.

FIG. 6 is a diagram comparing voltage stability in the same manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unit cell 2 Iron cup 3 Lithium sheet 4 Iron powder 5 Electrolyte layer 6 Positive electrode 7 Current collector 8a, 8b Lead piece 9 Insulating material 10 Case 11, 12 Cylinder 13 Top surface part 14 Bottom part 15 Cavity part 16a, 16b Terminal 17 Glass 18 jig 19 disk 20 cylinder

Continuing from the front page (72) Inventor Yasuhiro Nishimura 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Inventor Yasushi Watanabe 2 Nissan Motor Co., Ltd., 2 Takara-cho, Kanagawa-ku, Yokohama-shi Nissan Motor Co., Ltd. (72) Inventor Hitoshi Oyori 2 Nissan Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture

Claims (2)

[Claims] 1. A cylindrical sealed metal case having a positive electrode terminal and a negative electrode terminal and having at least one hollow portion penetrating in the axial direction, stacked in the metal case in the axial direction, and housed therein. A unit cell stack having a cavity corresponding to the cavity, an insulating layer that insulates the metal case from the unit cell stack, and a positive terminal and a negative terminal of the unit case, the positive terminal and the negative terminal of the unit cell stack. A thermal battery comprising a lead connected to a thermal battery. 2. A metal case comprising: two concentric cylinders; and an upper surface and a bottom surface for sealing the upper and lower parts of a space formed between the two cylinders, and provided with a positive electrode terminal and a negative electrode terminal. A unit cell stack that is stacked and housed in the space and has a hollow portion in the center, an insulating layer that insulates the metal case from the unit cell stack, and a positive electrode terminal and a negative electrode terminal of the unit cell stack in a metal case A lead connected to the positive electrode terminal and the negative electrode terminal.