NICKEL-HYDROGEN ACCUMULATOR BATTERY

摘要

There is provided a nickel-hydrogen accumulator battery capable of suppressing increase of discharge reserve of a negative electrode and suppressing lowering of the battery characteristic. The nickel-hydrogen accumulator battery (100) includes a battery main body (plate group 150, electrolyte, etc.) a case (102) containing the battery main body, and a safety valve device (101) having an excessive pressure preventing function for preventing excessive increase of the internal pressure in the case (102) by discharging the gas from the case (102) when the internal pressure of the case (102) exceeds a predetermined value. The safety valve device (101) includes a valve member (110) having a convex wall portion (118) forming an in-valve space C communicating with a gas discharge hole (122). In addition to the excessive pressure preventing function, the safety valve device (101) has a hydrogen leak out function for discharging hydrogen in the case (102) out of the battery via the in-valve space C even when the internal pressure in the case (102) is not greater than the predetermined value.