JPH07296823A - Thermal battery having piezoelectric ignitor - Google Patents

Abstract

PURPOSE:To enhance the reliability of ignition and to simplify the work of insulating a piezoelectric ignitor for use in a piezoelectric ignition type thermal battery by stabilizing the structure of the piezoelectric ignitor. CONSTITUTION:A piezoelectric ignition plug for use in a piezoelectric ignition type thermal battery is so constructed to have a piezoelectric ignitor in which a pair of bridges or bridged lead wires 17 are not provided with parallel portions but are secured to a bridge holder 16 serving as an explosive container, with an appropriate anode-cathode distance kept between them, and with an explosive 18 packed in the recessed portion of the bridge holder 16.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A thermal battery is a battery in which a eutectic salt such as KCl-LiCl is used as an electrolyte. Since the electrolyte is a non-conductive solid at room temperature, it is inactive as a battery but is heated to a high temperature. Then, the electrolyte becomes a molten salt having a good ionic conductivity and becomes a battery in an active state so that power can be supplied to the outside.

This type of battery has practically no self-discharge during storage, and exhibits the same characteristics as immediately after manufacture even after long-term storage. A heating agent for heating the unit cell is incorporated at the time of manufacture, and the heating agent can be activated when the battery is used to instantly activate the battery, which is convenient for emergency applications. Since Ca or Li, which cannot be used in the aqueous electrolyte solution, can be used in the negative electrode, the voltage per unit cell can be increased. Since it is operated at a high temperature, the electrode reaction is easy to proceed and it has high output characteristics. Since it has such characteristics, it has been put to practical use as a power source in the fields of various flying objects and induction equipment.

A thermal battery using a conventional piezoelectric igniter will be described with reference to FIG. In FIG. 1, 1 is Li as a negative electrode,
A unit cell ₂ having KCl-LiCl as an electrolyte and FeS ₂ as a positive electrode constitutes a power generation section in which a heating agent formed by molding a mixture of Fe and KClO ₄ is laminated. Reference numeral 8 denotes a heat insulating layer which is made of inorganic paper or the like and is arranged to keep the heat of the power generation section and prevent thermal 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 hermetically sealed at a fitting portion.

Reference numeral 3 denotes a piezoelectric igniter, which introduces a high voltage generated by applying an external pressure to the piezoelectric starting device 11 mounted outside the battery to the igniter terminal 4 so that the piezoelectric igniter uses the high voltage energy. The igniting agent of 3 ignites, burns to the ignition pad of 9 and further burns the heating agent 2 through the igniting zone arranged on the side of the power generation section, 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 activation has a bridge lead wire 13 which also serves as a bridge and is made of plastic or glass. They are arranged in parallel via the body 12. The distance between the spark discharge parts of a normal bridge is 0.6 to 0.8 mm, while the bridge lead wire is fixed at around 1.0 mm, and the insulation distance is not sufficiently secured.
Therefore, there is a problem that high voltage energy is leaked, reliability of ignition is poor, and 20 to 30% of the ignition powder 14 containing Zr as a main component does not ignite.

As means for solving the problem, 15 in FIG.
The exposed part of the bridge lead wire 13 was insulated with epoxy resin etc. as shown in, but it still couldn't eliminate 1-5% of non-ignition and 10-15
Satisfactory results were not obtained, such as taking minutes.

Further, if the outer diameter of the piezoelectric igniter is large, for example, 10 mm or more, the distance between the lead wires of the bridge can be secured, but this is not a preferable means in view of the characteristics of a thermal battery that requires a small size and high output.

The present invention solves the above problems, and an object of the present invention is to provide a piezoelectric igniter for a thermal battery, which is not poor in reliability of ignition and which can simplify the manufacturing process.

[0010]

In order to solve this problem, the present invention is devised in a method of holding a bridge lead wire of a piezoelectric igniter, and insulates by fixing and fixing each bridge in a horizontal state. Measures are taken by means of securing a distance.

[0011]

As described above, the leakage of high voltage energy is prevented, the reliability of ignition is improved, and the conventional insulation treatment time for exposing the lead wire of the bridge is unnecessary.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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. Reference numeral 17 is a bridge lead wire that also serves as a bridge, and as shown in the figure, the bridges are made of plastics and are held at a distance of 0.4 to 0.8 mm with the bridges facing each other.
It is held and fixed at 6. Further, the depression of the bridge holder 16 is filled with an ignition charge 18 mainly containing zirconium. The piezoelectric igniter configured as described above is attached to the portion of the piezoelectric igniter 3 of FIG. 1 described in the conventional example, and is generated by applying an external pressure to the piezoelectric starter 11 mounted outside the battery as in the conventional case. By introducing a high voltage to the igniter terminal 4, the igniting agent of the piezoelectric igniter is ignited by the high voltage energy, and the igniting agent of the piezoelectric igniter is burned and transferred to the pad of 9 and the heating agent 2 through the ignition zone arranged on the side of the power generation section. Burns,
The unit cell 1 is activated and electric power is supplied to the outside through the output terminals 6 and 7.

A thermal battery provided with the piezoelectric igniter of the present invention, 10
When the activation test was performed on 0 pieces, all the piezoelectric igniters ignited and the battery was activated normally.

[0015]

As described above, the piezoelectric igniter of the present invention is a highly useful invention in that it has a high reliability of ignition and that the insulation treatment of the bridge lead portion is not required and the number of manufacturing steps is reduced.

[Brief description of drawings]

FIG. 1 is an overall structural cross-sectional view of a thermal battery equipped with a piezoelectric igniter.

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

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

[Explanation of symbols]

 1 Unit Battery 2 Exothermic Agent 3 Piezoelectric Ignition Device 4 Ignition Device Terminal 6 Output Terminal 7 Output Terminal 8 Thermal Insulation Layer 9 Ignition Pad 10 Exterior Container 11 Piezoelectric Starter 12 Bridge Lead Wire Holder 13 Bridge Lead Wire 14 Ignition Charge 15 Epoxy resin, etc. (insulation treatment) 16 Bridge retainer 17 Bridge lead wire 18 Explosive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Kimura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A thermal battery comprising a power generator in which a unit cell and a heat generating agent are alternately laminated, an ignition pad for igniting the heat generating agent, and a piezoelectric igniter ignited by a piezoelectric starting device. A pair of bridges or bridge lead wires are fixed by holding an appropriate inter-electrode distance relative to the insulating bridge holder that also serves as the pyrotechnic container without providing parallel parts. A thermal battery provided with a piezoelectric igniter, characterized in that a body recess is filled with an ignition agent.