JPH0757721A - Ptc device and constitution battery having ptc device - Google Patents

Abstract

PURPOSE:To enhance the heat resistance and thermal shock resistance of a PTC device and to maintain safety and reliance of a battery and a constitution battery using the PTC device for a long term. CONSTITUTION:In a PTC device A, the surface except for a part from which a metallic lead 3 is taken out is covered with a heat resistant polyparaxylene resin 4. The heat resistance of the PTC device is increased. The reliability and safety of a constitution battery using the PTC device A are enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a PTC device and a PT.
The present invention relates to a constituent battery provided with a C device.

[0002]

2. Description of the Related Art Conventionally, a PT is formed by crimping a metal plate with a metal lead connected to a PTC element (POSITIVE TEMPERATURE C0EFFICIENT) which is an overcurrent and heat protection element.
In the normal state, the C device is a resistor of several tens of milliohms in the normal state, but it becomes a resistor of several tens of ohms in a short time due to abnormal energization and temperature rise from the outside. It has the characteristic of returning to a low resistance body. For this reason, as the structure of the PTC element, as shown in FIG.
The thickness of the metal plate 2 was set to about 0 μm, the thickness of the metal plate 2 was set to about 30 to 100 μm, and the metal lead 3 was covered with the insulating resin 4 and the like except for the lead-out portion, so that the PTC device A was not short-circuited. This PTC device A is used for primary batteries such as lithium batteries, manganese dry batteries, and alkaline manganese dry batteries, and secondary batteries such as nickel-cadmium batteries, nickel-hydrogen, and silver storage batteries to provide a constituent battery with improved safety as a power source. Was.

[0003]

[Problems to be Solved by the Invention] However, PTC
When the PTC device operates due to abnormal energization of the device A from the outside, the temperature of the PTC element 1 rises, and when the excess current from the outside is removed and the temperature returns to room temperature, the PTC device A is exposed to thermal shock. Join. When this phenomenon was repeated, the insulating resin 4 cracked, and in an extreme case, the insulating resin was lost, and the PTC device A was short-circuited depending on the conditions, and the safety of the battery could not be maintained. .

The present invention is intended to solve such problems, and an object thereof is to enhance environmental stress resistance such as heat resistance and thermal shock resistance of a PTC device.

[0005]

The present invention is achieved by using a polyparaxylylene-based resin having excellent heat resistance, thermal shock resistance and mechanical properties as a resin coating of a PTC device.

[0006]

FUNCTION The polyparaxylylene resin has the chemical structural formula shown in (Chemical formula 1). This is superior to conventional ABS resin in heat resistance and has mechanical strength such as abrasion resistance and impact resistance.
It has three times stronger physical properties. Therefore, the function of the PTC device can be maintained for a long period of time.

[0007]

[Chemical 1]

[0008]

EXAMPLES Examples of the present invention will be described below. Figure 1 (a)
Is a cross-sectional view of a PTC device A using a polyparaxylylene resin, (b) is a plan view thereof, and 1 is a PTC element in which fine powder of a conductor such as carbon black or graphite is dispersed in polyethylene resin. It is molded into a sheet with a thickness of several tens of μ. Reference numeral 2 denotes Ni, Ni alloy, Cu, Cu having a thickness of several tens of μm which is pressure bonded to the PTC element.
A metal plate made of an alloy. A metal lead plate 3 is electrically connected to the metal plate 2 and is usually made of the same material as the metal plate 2. An insulating resin 4 is a polyparaxylylene-based resin coated on a portion of the metal lead plate excluding the lead take-out portion.

2 to 4 are a front view, a right side view and a plan view of a camera lithium battery equipped with the PTC device A shown in FIG. In the figure, 5 is a battery storage case. B is a cylindrical manganese dioxide lithium battery, two of which are used, and the batteries are electrically connected by a PTC device A by a method such as resistance welding or laser welding. Reference numerals 6 and 7 denote positive and negative terminal holes provided on the bottom of the case 5. Reference numeral 8 denotes a lid that closes the upper opening of the case 5 and is made of the same material as the case. The lid and the case are integrally joined by ultrasonic welding or an adhesive material. Regarding the PTC device of the present invention configured as described above, a conventional insulating resin is used, and a temperature atmosphere of −20 ° C. on the low temperature side and 100 ° C. on the high temperature side is used for 4 hours each for a total of 8 hours. The occurrence rates of cracking / falling off of the coating resin when the thermal shock test was performed as one cycle were compared. The results (Table 1)
Shown in. The number of test pieces was 500.

[0010]

[Table 1]

[0011]

As is clear from (Table 1) above, according to the present invention, the heat resistance and thermal shock resistance of the PTC device can be improved by using the polyparaxylylene resin as the insulating resin material. The environmental stress resistance such as can be made extremely strong. Therefore, the reliability and safety of the PTC device and the constituent batteries can be maintained for a long time.

[Brief description of drawings]

1A is a cross-sectional view of a PTC device of the present invention, and FIG. 1B is a plan view thereof.

FIG. 2 is a front view of a constituent battery provided with the PTC device of the present invention.

FIG. 3 is a right side view of a constituent battery provided with the PTC device of the present invention.

FIG. 4 is a plan view of a constituent battery provided with the PTC device of the present invention.

[Explanation of symbols]

 1 PTC Element 2 Metal Plate 3 Metal Lead 4 Insulating Resin (Polyparaxylylene Resin) 5 Battery Storage Case 6, 7 Terminal Hole 8 Lid A PTC Device B Battery

Claims (2)

[Claims] 1. A PTC device in which a metal plate and metal leads are laminated on both upper and lower surfaces of a PTC element, and the surface of the PTC device is covered with a polyparaxylylene resin except for the lead-out portion of the metal lead. Characteristic PTC device. 2. A PTC device in which a metal plate and a metal lead are laminated on the upper and lower surfaces of a PTC element, and the surface of the PTC device is covered with a polyparaxylylene-based resin except for the lead-out portion of the metal lead. A battery comprising a PTC device, wherein the battery is connected between the batteries.