Electrical device and assembly

摘要

A circuit protection device (1) is formed from a resistive element (3) composed of a PTC conductive polymer composition (5) and two electrodes (7,9). The conductive polymer composition contains ethylene/vinyl acetate copolymer having a vinyl acetate component of less than 30% by weight of the copolymer, and a melting point of at most 105 DEG C. Devices of the invention have a resistive element thickness of 0.025 to 0.25 mm; a crosslinking level equivalent to 1 to 20 Mrads; a surface area of at most 120 mm<2>; a resistance at 20 DEG C, R20, of at most 0.050 ohm; and a PTC anomaly from 20 DEG C to (Tm+5 DEG C) of at least 10<3.5>. The devices can be used as part of an assembly (15) in which the device is in contact with a battery (17), e.g. a rechargeable battery.