PTC ELEMENT, PTC ELEMENT-MOUNTED PCB BOARD, SECONDARY CELL PROTECTION CIRCUIT DEVICE AND SECONDARY CELL ASSEMBLY

A PTC device formed integrally on a PCB substrate, such a PCB substrate, a secondary battery protection circuit device comprising such PCB substrate provided with a circuit to control the voltage and current of secondary batteries, and a secondary battery assembly provided with said device. A PCB substrate 1 is provided with an electronic component 2 and a PTC device 3. The PTC device 3 has a construction having a PTC material 6 in the centre, which is provided with foils 7, 7 made of nickel foil on its top and bottom; an outlet electrode 4 is provided on the foil 7, and an outlet electrode 5, provided on the PCB substrate, is soldered below.