Abstract: Disclosed is an electrochemical device including an electrode assembly having a cathode, anode and an electrolyte, and a casing surrounding the electrode assembly. The device further includes a protection device to which either or both of a cathode lead for connecting a cathode with an outer terminal and an anode lead for connecting an anode with an outer terminal are connected electrically, wherein the protection device is disposed in the inner space of the casing and the electrode lead equipped with the protection device is folded at both sides of the protection device so that the largest surface of the protection device is layered on a lateral surface of the casing where the electrode lead is present.

Abstract: PTC conductive polymer composition includes organic polymer containing polyolefin components essentially consisting of 30˜40 w % high density polyethylene (HDPE), 20˜40 w % low density polyethylene (LDPE) and 10˜30 w % ethylene-acrylic-acid (EAA) or ethylene-vinyl-acetate (EVA), and 20˜30 w % high or low density polyethylene which is denaturated into maleic anhydride compound; 60˜120 w % electrical conductive particles dispersed into the organic polymer, the electrical conductive particles by weight of the organic polymer; and 0.2˜0.5 w % peroxidic cross-linking agent added for cross-linking reaction by weight of the organic polymer. Thus, it becomes possible to control PTC characteristics such as switching temperature and trip time of an electrical device by suitably adjusting an added amount of the polyethylene, which is denaturated into maleic anhydride compound.

Abstract: An electrical device including a PTC conductive polymer sheet, and first and second electrodes physically contacted with opposite surfaces of the conductive polymer sheet is disclosed. The first and second electrodes have a plurality of protrusions protruded from surfaces thereof, respectively. The protrusions have an surface roughness (Rz) of 1 to 20 ?m and an average width ({overscore (Rw)}) which is 0.5 to 2 times of the surface roughness (Rz), and an average gap ({overscore (Rg)}) between adjacent protrusions is 0.5 and 2 times of the surface roughness (Rz). The conductive polymer sheet has a thickness which is more than 5 times of the surface roughness (Rz).

Abstract: An electrical device including a PTC conductive polymer sheet, and first and second electrodes physically contacted with opposite surfaces of the conductive polymer sheet is disclosed. The first and second electrodes have a plurality of protrusions protruded from surfaces thereof, respectively. The protrusions have an surface roughness (Rz) of 1 to 20 &mgr;m and an average width ({overscore (Rw)}) which is 0.5 to 2 times of the surface roughness (Rz), and an average gap ({overscore (Rg)}) between adjacent protrusions is 0.5 and 2 times of the surface roughness (Rz). The conductive polymer sheet has a thickness which is more than 5 times of the surface roughness (Rz).

Abstract: PTC conductive polymer composition includes organic polymer containing polyolefin components essentially consisting of 30˜40 w % high density polyethylene (HDPE), 20˜40 w % low density polyethylene (LDPE) and 10˜30 w % ethylene-acrylic-acid (EAA) or ethylene-vinyl-acetate (EVA), and 20˜30 w % high or low density polyethylene which is denaturated into maleic anhydride compound; 60˜120 w % electrical conductive particles dispersed into the organic polymer, the electrical conductive particles by weight of the organic polymer; and 0.2˜0.5 w % peroxidic cross-linking agent added for cross-linking reaction by weight of the organic polymer. Thus, it becomes possible to control PTC characteristics such as switching temperature and trip time of an electrical device by suitably adjusting an added amount of the polyethylene, which is denaturated into maleic anhydride compound.

Abstract: An electrical device having PTC conductive polymer is made by combining electrodes, in which electroless nickel plating is formed on an electrolytic copper foil, with PTC conductive polymer. The electrodes have electroless-plated nickel layers at both sides of an electrolytic copper foil and the PTC conductive polymer is welded between the electrodes in a sandwich type.