Battery

A battery comprising a cell, a battery management unit for managing the cell, a protection case holding the battery management unit, a housing containing the cell and the protection case, an external connection terminal connected electrically to the cell, and a fuse or a relay, and a wiring board having a wiring that electrically connects the cell to the battery management unit, wherein

• the protection case inside is hermetically sealed,
• the protection case is provided with lead connection terminals that lead from the inside of the protection case to the outside,
• at least one of the lead connection terminals electrically connects the battery management unit to the cell,
• the fuse or the relay is placed at a pathway for electrically connecting the cell to the external connection terminal,
• the battery management unit is configured to output a signal to shut off the electric connection between the cell and the external connection terminal with use of the fuse or the relay once the battery management unit detects an overcharge of the cell,
• the housing comprises a lid and a container for containing the cell,
• the wiring board is situated between the cell contained in the container and the lid, and
• the protection case is situated between the wiring board and the lid.