JPH02281565A - Thermal cell - Google Patents

Abstract

PURPOSE:To obtain a battery of excellent reliability with less possibility of its insulating member being damaged by setting the ratio and difference of/ between the outside diameter of an ignition pad and that of a heating agent in a specific region, and bringing the ignition pad and the heating agent in contact with each other. CONSTITUTION:The outside diameter of an ignition pad 13 is made smaller than that of a heating agent 2 within the range of 70 to 90%, and the size difference between them is reduced to within 10mm, and the pad 13 and the heating agent 2 are further brought in contact with each other. Thereby burning is not directly transmitted from the pad 13 to a fuse band 5 but is first transmitted to the heating agent 2 and is next transmitted to the fuse band 5 via the heating agent 2. The reaction residue of the pad 13 is therefore fixed integrally with the reaction residue of the heating agent 2 so that there is less possibility of an insulating member being broken. Thus, without forming an internal discharge circuit for a positive electrode lead plate 8' nor for a negative electrode lead plate 9', a battery excellent in duration and reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to improving the insulation between internal lead plates in a lithium/iron disulfide thermal battery.

BACKGROUND TECHNOLOGY A thermal battery is inactive at room temperature, but becomes active when heated to a high temperature and can supply power to the outside, and is a type of storage battery. Therefore, even after storage for 6 to 10 years or more, the battery characteristics remain the same as they were immediately after manufacture, so they are used as an emergency power source. In addition, since it is operated at high temperatures, electrode reactions can easily proceed, so there is little polarization, so it has excellent large current discharge properties, and when desired, it has features such as instantaneous power extraction when a start signal is input.

Most of these types of batteries have a heat generating agent built in, and the heat generated by the heat generating agent melts a molten salt that is solid at room temperature and has no ion conductivity, and is activated as a battery.

The structure of a conventional thermal battery will be explained using FIG. In the figure, 1 is a unit cell, 2 is a heating agent, and a heat storage layer 3 is arranged at both upper and lower ends of a power generation part in which these are laminated alternately to moderate heat radiation and maintain an operating temperature for a long time.

A unit cell, an ignition puff drum having the same diameter as the heating agent, and an igniter 4 are constructed at the upper end of this laminate. There is a fuse cord 5 on the side of the stack, and a positive electrode lead plate 8' and a negative electrode lead plate 9' are pulled out from the top and bottom of the stack at positions that do not overlap with the fuse cord, and the positive terminal 8 is pulled out from the top and bottom of the stack. ．． It is welded to the negative electrode terminal 9. Other components include a pair of igniter external terminals7. It has a heat insulating material 12, and the fitting portion of the outer cover 1° and the outer case 711 is welded to hold the stacked body at a constant pressure.

Regarding the conventional thermal battery configured as above.

The operation will be explained below. First, when a minute current is applied from the igniter external terminal 7, a small flame is generated from the igniter 4. This small flame burns the ignited buff mud, becomes a large spark, burns the fuse cord 6, and heats the heating agent 2 between the cells.
ignition and combustion spread.

The unit cell 1 is heated by causing an exothermic reaction at high speed and in large quantities. The temperature of the unit cell is raised to 400 to 700° C., the electrolyte is melted, and the cell enters a discharge start state, outputting voltage and current from the positive and negative terminals 8.9. The ignition pad is zirconium (Zr)
and barium chromate (BaCrO4), and has electrical conductivity in the red-hot state immediately after combustion, but 11
When it is below 1, it cools down and becomes insulated. Furthermore, since the lead plates of both poles are in close contact with the sides of the laminate, they are covered with an insulating member or a heat-resistant heat insulating material so that they do not come into direct contact with the unit cells.

Problems to be Solved by the Invention However, in the above configuration, even if the lead plate is protected by an insulating member, the ignition pad burns during startup, and the reaction products are deformed and spread in the outer circumferential direction, and the combustion heat ( Approximately 2
000°C), the insulating member and heat insulating material are destroyed, and the electrical conductivity becomes several tens to hundreds of ohms. There was a problem in that the reaction residue directly contacted the lead plate and formed an internal discharge circuit between the positive electrode and the negative electrode via the ignition pad reaction residue. In order to solve this problem, the conventional construction was to remove the ignition pad located directly below the igniter as shown in FIG. 4, and directly place the heating agent, which is hardly deformed by combustion. However, in this case, although no internal discharge circuit is formed, it takes 1706 seconds to reach the specified voltage after turning on the ignition trigger!
A problem arose in that the speed was almost twice as slow from i to 320m5.

The present invention solves the above-mentioned conventional problems.

To provide a highly reliable thermal battery that does not impair startup time and does not form an internal discharge circuit when starting the battery.

Means for Solving the Problems To achieve this object the invention provides an igniter and a heating agent consisting of a mixture of iron and potassium perchlorate.

An ignition pad made of the same material as the conventional one consisting of a mixture of zirconium and barium chromate is used, and the outer diameter of the ignition pad is made smaller within the range of 70% to 90% of the diameter of the unit cell and the heating agent, and the dimensions of both are small. The difference is small within 10H,
Furthermore, one ignition pad and the heating agent are in contact with each other.

Effect: According to this configuration, the reaction residue of the ignition pad after combustion is difficult to spread together with the reactant of the heating agent, and therefore,
There is little damage to the insulating members of the positive and negative electrode leads, and there is a gap between them, making it difficult to contact them. For these reasons, even if high combustion heat is generated, the breakdown of the insulating member will not impart conductivity to the reaction residue of the ignition pad, and the phenomenon of forming an internal discharge circuit can be prevented. Furthermore, since the present invention can be adopted based on the conventional structure, it does not involve any technical difficulties. Therefore, it is possible to construct a thermal battery that is easy to manufacture, has no delay in start-up time, and has excellent reliability.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to one drawing.

(Example 1) Fig. 1 shows a thermal battery with a structure in which an improved ignition pad 13 with a smaller diameter than the conventional ignition pad is brought into contact with a heating agent 2 provided below. It has the same configuration as the conventional example shown in FIG. The feature of this configuration is that combustion is not transmitted directly from the improved ignition pad 13 with a diameter of 45 m to the fuse cord 6, but is transmitted to the heating agent 2 with a diameter of esow, and is carried out via the heating agent 2. It's right there. By doing so, the reaction residue of the improved ignition pad becomes one with the reaction residue of the heating agent, becomes fixed and difficult to spread, and becomes difficult to destroy the insulating member.

(Embodiment 2) FIG. 2 is a sectional view of a thermal battery according to another embodiment of the present invention, and the basic configuration is almost the same as that of FIG. 1. The feature of this example is that the improved ignition pad 13 with a diameter of 40ff has an outer diameter of 5Qj.
It is placed inside the donut-shaped heating agent 14 with an inner diameter of 4oH, and is in contact with the thick part.

It is a method that spreads the combustion method, and the effect of the high-temperature combustion heat emitted from the improved ignition pad is further suppressed. Therefore, the influence on insulating members and heat insulating materials can be reduced more reliably.

The rise time of Example 1.2 above is 0.468 fl/m
The outer diameter of the ignition pad, which has a high combustion speed of s, is small, so it is 0.117ff/! After the igniter releases a flame as the Ils heating agent burns.

The time it takes for the heating agent at the bottom to finish burning is delayed by 1 ems in Example 1 and by 321n8 in Example 2. However, this degree of delay is not a practical problem, and the time until power generation starts depends on the product of the combustion speed and combustion length, the melting time of the electrolyte in the unit cell, and the gap between the layers of the stack. It is further relaxed because it depends on the heat transfer speed. As a result, the average rise time and discharge duration of 20 batteries each having a cell diameter of 501 ff and a laminate height of 80101 were as follows.

The discharge duration was significantly improved in each of the examples, and was approximately 1.6 times longer than in conventional example 1, indicating that the insulation between the positive and negative lead plates was maintained. Therefore, it can be assumed that the formation of an internal discharge circuit could be prevented.

The dimensions of the improved ignition pad were confirmed by changing various experimental conditions, and in Example 1, it was not necessary to make the outer diameter of the heating agent 5H or more on one side, that is, 10M or more in diameter, as long as it was at least 3mm. Maintain reliability. Also,
If the heating agent size and the improved ignition pad size ratio satisfy the above conditions and the improved ignition pad is 70% or more smaller,
This was disadvantageous in rise time and ignitability, and when it was increased by 90% or more, many variations occurred due to the influence on the insulating member.

Effects of the Invention As is clear from the above description, the present invention provides a method in which the ratio of the outer diameter of the heating agent to the outer diameter of the improved ignition pad is within the range of 70% to 90%, and the dimensional difference between the two is within the maximum value of 10ff. , a thermal battery configured with a minimum value of 3111 or more reduces deformation of the ignition pad and damage to insulating members and heat insulating materials due to high-temperature combustion heat. The formation of a discharge circuit is eliminated, and as a result, the duration can be extended. Furthermore, since the rise time is only slightly affected, this does not pose a practical problem.

Therefore, it is highly reliable and has a quick start-up time with only minor modifications. Moreover, it is possible to provide a thermal battery with improved duration.

[Brief explanation of drawings]

1 and 2 are longitudinal sectional views of a thermal battery according to an embodiment of the present invention, and FIGS. 3 and 4 are longitudinal sectional views of a conventional thermal battery. 2... heating agent, 4... igniter, 5...
...Fuse cord. 8'... Positive electrode lead plate, 9'... Negative electrode lead plate, 13... Improved ignition pad, 14...
...Doughnut-shaped heating agent. Name of agent: Patent attorney Shigetaka Awano and 1 other person f.
-・4munoto Masaki wo Hatake) +-[1 possible・-7+]% agent 3-1 outer layer 8'--Kazumasa 1 degree Y main layer 9-poor cotton 1 1--1 1-710 Yuliu q--k to Geummi to--- 9LX iris n-ichita L γ-s

Claims (1)

[Claims] In a thermal battery having an igniter, a heating agent made of a mixture of iron and potassium perchlorate, and an ignition pad made of a mixture of zirconium and barium chromate, the outer diameter of the ignition pad is smaller than the outer diameter of the heating agent. The minimum size is 3mm or more and the maximum size is 10mm or less, and the ratio is 70mm.
% to 90%, and both are in contact.