Battery pack and method of detecting battery pack abnormalities

摘要

The battery pack is provided with a rechargeable battery that can be charged, and a protection device to protect the rechargeable battery when an abnormality occurs. The protection device is provided with an externally exposed first output terminal connected to the first electrode of the rechargeable battery, an externally exposed second output terminal connected to the second electrode of the rechargeable battery, and an externally exposed third output terminal for signal detection as output terminals, and a contact switching section that can switch contact when a rechargeable battery abnormality is detected. The protection device is formed as a single piece with the output terminals and contact switching section. The contact switching section has one end connected to the second electrode of the rechargeable battery, the other end is connected to allow switching between a contact connected to the second output terminal and a contact connected to the third output terminal. When no abnormality is detected the other end is connected to the contact connected to the second output terminal, and when an abnormality is detected the other end switches to the contact connected to the third output terminal.