BREAKER, SAFETY CIRCUIT INCLUDING SAME, AND SECONDARY BATTERY PACK

摘要

A breaker (1) includes: a fixed piece (2) that has a fixed contact (21); a movable piece (4) that has a movable contact (3), and presses the movable contact (3) against the fixed contact (21) to bring the movable contact (3) into contact with the fixed contact (21); a thermally-actuated element (5) that actuates the movable piece (4) so as to separate the movable contact (3) from the fixed contact (21) by deformation with changes in temperature; and a resin case (7) that houses the fixed piece (2), the movable piece (4), and the thermally-actuated element (5). A lid member (72) of the resin case (7) is molded integrally with a plate-like cover piece (8) having bead portions (81). The bead portions (81) reinforce the lid member (72), and the breaker (1) can be further reduced in size and thickness while maintaining a stable contact/non-contact state between the fixed contact (21) and the movable contact (3).