Abstract: A battery case lid is formed by working a metal plate, and includes a substrate section and an explosion-proof valve formed in the substrate section. The explosion-proof valve has a reduced thickness section thinner than the substrate section, and the reduced thickness section is formed by extending the metal plate by applying pressure while the metal plate is kept unrestrained.

Abstract: A battery case provided with a safety valve (4) in which a breakage groove (45) is used, wherein in order to stabilize the operation pressure, a lid (2) of the battery case has formed thereon: a thin plate portion (30) obtained by thinning a plate part (3); and a first recessed part (40) comprising a curved part (44) in which the thin plate portion (30) is indented inward, with respect to the case, in a curved shape. The breakage groove (45) for the safety valve (4) is formed at the bottom part (440) of the curved part (44). A first connecting portion (46) and a second connecting portion (47) of the plate part (3), which connect to the curved part (44) on both sides flanking the curved part (44), are at positions protruding toward the outside of the case from the plate part (3).

Abstract: A battery case lid is formed by working a metal plate, and includes a substrate section and an explosion-proof valve formed in the substrate section. The explosion-proof valve has a reduced thickness section that is thinner than the substrate section, and the reduced thickness section is formed by extending the metal plate by applying pressure while the metal plate is kept unrestrained.

Abstract: Provided is a battery case lid (1) formed by working a metal plate, including: a substrate section (2) and an explosion-proof valve (4) formed in the substrate section (2), wherein the explosion-proof valve (4) has a reduced thickness section (41) thinner than the substrate section (2), and the reduced thickness section (41) is formed by extending the metal plate by applying pressure while the metal plate is kept unrestrained.

Abstract: It is an objective of the present invention to provide a battery case lid and a manufacturing method for the battery case lid which inhibit work hardening of a metal plate workpiece and which facilitate manufacture of a battery case lid. Provided is a battery case lid (1) formed by working a metal plate, including: a substrate section (2) and an explosion-proof valve (4) formed in the substrate section (2), wherein the explosion-proof valve (4) has a reduced thickness section (41) thinner than the substrate section (2), and the reduced thickness section (41) is formed by extending the metal plate by applying pressure while the metal plate is kept unrestrained.