Composite material and polymer positive temperature coefficient thermistor made of composite material

Abstract

The invention discloses a composite material and a high molecular positive temperature coefficient thermistor made of the composite material. The composite material includes a high molecular crystalline polymer, a conductive filler and a compatibilizer; the high molecular crystalline polymer occupies a composite The weight percentage of the material is 5-15 wt%, the conductive filler occupies 70-95 wt% of the composite material, and the compatibilizer occupies 0.5-2 wt% of the composite material; the conductive filler is a mixture of carbide and metal tungsten, and the metal tungsten occupies the weight of the conductive filler Percentage 2~6wt%; compatibilizer is ethylene-vinyl alcohol copolymer, thermistor comprises two layers of conductive layers and a composite material layer, composite material layer is placed between two layers of conductive layers, composite material layer is made of composite material The thermistor has the characteristics of low initial resistance, and at the same time, it can still maintain low resistance characteristics after multiple high and low temperature cycles, which meets the stability of lithium batteries.

Description

technical field [0001] The invention relates to a composite material used in electronic components and a polymer positive temperature coefficient thermistor made of the composite material. Background technique [0002] The polymer positive temperature coefficient thermistor can maintain an extremely low resistance value at normal temperature, and has the characteristic of being sensitive to temperature changes, that is, when an overcurrent or overtemperature occurs in the circuit, its resistance will instantly increase to one High resistance value keeps the circuit in an open circuit state to achieve the purpose of protecting circuit components. Therefore, conductive composite materials with a positive temperature coefficient of resistance can be connected to the circuit. As materials for current sensing components, such conductive composite materials have been widely used in electronic circuit protection components. [0003] However, with the popularization of electric loc...

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Problems solved by technology

[0005] In order to make the polymer positive temperature coefficient thermistor have excellent resistance reproducibility after repeated high and low temperature cycles, the prior art uses a coupling agent or maleic anhydride grafted polyethylene to increase the polymer and The interface binding property of conductive particles, however, if a coupling agent is used, there will be a problem of precipitation of the coupling agent during use

If maleic anhydride-grafted polyethylene is used, because the grafting rate of maleic anhydride-grafted polyethylene is low, generally only 0.4% to 2%, so in order to achieve the purpose, grafted polymers such as maleic anhydride are required. A large amount will affect the resistance value

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