SECONDARY BATTERY WITH PROTECTIVE CIRCUIT

摘要

A secondary battery (101) arranged such that a thermal element (133) exhibiting a resistance changing dependent on temperature variation is removed from a passage that the charge/discharge current of a power storage unit (111) runs, an auxiliary switch element (122) is conducted by variation in the resistance of the thermal element (114) caused by heat generated when the main switch element (114) is heated with an overcurrent, and first and second auxiliary fuse elements (135a, 135b) are blown out. A high efficiency is ensured because power is not consumed in the thermal element (133) by the charge/discharge current. Furthermore, the size can be reduced because a thermal element (133) having a low current capacity can be employed.