JP3178234B2 - Thermal battery with piezoelectric igniter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a piezoelectric igniter used for a thermal battery.

[0002]

2. Description of the Related Art A thermal battery is a battery using a eutectic salt such as KCl-LiCl as an electrolyte. At room temperature, the electrolyte is a non-conductive solid, so the battery is inactive but heated to a high temperature. Then, the electrolyte becomes a favorable ion-conductive molten salt, and becomes an active state as a battery, so that the battery can supply power to the outside.

[0003] This type of battery has practically no self-discharge during storage, and exhibits the same characteristics as immediately after production even after long-term storage. The exothermic agent for heating the unit cell is incorporated at the time of manufacturing, and the exothermic agent acts when the battery is used, so that the battery can be activated instantaneously, which is convenient for emergency use. Since Ca and Li, which cannot be used in the aqueous electrolyte solution, can be used for the negative electrode, the voltage per unit cell can be increased. Since the electrode is operated at a high temperature, the electrode reaction easily proceeds and has high output characteristics. Because of these features, it has been put to practical use as a power source in the fields of various flying objects and guidance equipment.

A conventional thermal battery using a piezoelectric igniter will be described with reference to FIG. In FIG. 1, 1 is Li for a negative electrode,
A unit cell having KCl-LiCl as an electrolyte and FeS ₂ as a positive electrode, and a power generating unit 2 is composed of a heating agent formed by molding a mixture of Fe and KClO ₄ . Numeral 8 denotes a heat insulating layer made of inorganic paper or the like, which is arranged to keep the temperature of the power generation unit and to prevent heat damage to peripheral equipment of the thermal battery. Reference numeral 10 denotes a metal outer container, which includes a case and a lid, and is welded and sealed at a fitting portion.

Reference numeral 3 denotes a piezoelectric igniter which guides a high voltage generated by applying an external pressure to a piezoelectric actuating device 11 mounted outside the battery to the igniter terminal 4, and uses the high voltage energy to generate a piezoelectric igniter. The pyrotechnic charge 3 ignites and burns to the ignition pad 9 and the heating agent 2 burns through the squib arranged on the side of the power generation unit, and the unit cell 1 is activated to the outside through the output terminals 6 and 7. Power is supplied.

[0006]

However, as shown in detail in FIG. 2, the piezoelectric igniter provided for starting has a bridge lead wire 13 serving also as a bridge, made of plastic or glass. They are arranged in parallel via the body 12. Normally, the distance between the poles of the spark discharge portion of the electric bridge is 0.6 to 0.8 mm, whereas the electric lead of the electric bridge is fixed at about 1.0 mm, and the insulation distance is not sufficiently secured.
For this reason, high voltage energy leaks and the reliability of ignition is poor, and there is a problem that 20 to 30% of the ignition charge 14 mainly composed of Zr does not ignite. In addition, when a thermal battery is used, a high impact is applied to the battery body, the lead wire of the bridge may be deformed, the insulation distance may be reduced, and the battery may be easily leaked.

In order to solve this problem, the present invention devises a method of insulating and holding a bridge lead wire of a piezoelectric igniter to suppress leakage, prevent deformation of the bridge lead wire, and improve reliability of ignition. It is characterized by improving.

[0008]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention provides a thermal battery having a piezoelectric igniter, in which an electric bridge lead wire of the piezoelectric igniter and an outer container are coated and fixed with an insulating resin. It has a piezoelectric igniter.

[0009]

As described above, the reliability of ignition is improved by preventing the leakage of high-voltage energy and preventing the deformation of the electric bridge lead wire.

[0010]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 3 is a sectional view of a piezoelectric igniter according to an embodiment of the present invention. The electric bridge lead wire 13 extending from the lower portion of the electric bridge holding member 12 is applied to the entire surface with an epoxy resin 15 and simultaneously adhered and fixed to the outer container 10.

[0012] 100 batteries were prototyped using the piezoelectric igniter 3 having the above-described structure, and after applying a high impact of about 20,000 G, an ignition test was carried out. As a result, it was confirmed that all of the batteries ignited. Further, in this example, an epoxy resin was used, but a phenol resin, a silicone resin, a polyimide resin, and a polyphenylene sulfide resin were used, but similar results were obtained.

[0013]

As described above, the piezoelectric igniter of the present invention can supply a piezoelectric ignition type thermal battery with high ignition reliability without being affected by high impact.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the entire structure of a thermal battery provided with a piezoelectric igniter.

FIG. 2 is a cross-sectional view showing a conventional piezoelectric igniter.

FIG. 3 is a sectional view showing a piezoelectric igniter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unit cell 2 Heating agent 3 Piezoelectric igniter 4 Ignition terminal 6 Output terminal 7 Output terminal 8 Heat insulation layer 9 Ignition pad 10 Outer container 11 Piezoelectric starter 12 Electric bridge lead wire holder 13 Electric bridge lead 14 Explosive 15 Epoxy resin etc. (insulation treatment)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruo Yamane 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 6/36 JICST File (JOIS)

Claims (1)

(57) [Claims] 1. A thermal battery comprising: a power generator in which a unit cell and a heating agent are alternately stacked; an ignition pad for igniting the heating agent; and a piezoelectric igniter that is ignited by a piezoelectric activation device. A thermal battery equipped with a piezoelectric igniter made by coating and fixing an electric bridge lead wire and an outer container with an insulating resin.