BATTERY PACK, AND BATTERY SYSTEM

摘要

[PROBLEMS] To provide a battery pack wherein a plurality of secondary batteries are connected in series-parallel and unnecessary power loss is reduced for reducing variation in charging depth occurring between respective secondary batteries, and to provide a battery system. [MEANS FOR SOLVING PROBLEMS] The battery system comprises a switching element (Q11) for opening/closing the charging passage of a battery pack (B1), a switching element (Q12) for opening/closing the discharging passage of the battery pack (B1), a switching element (Q21) for opening/closing the charging passage of a battery pack (B2), and a switching element (Q22) for opening/closing the discharging passage of the battery pack (B2). When the battery pack (B1) is charged, the switching elements (Q12, Q21) are turned off and the switching element (Q11) is turned on until the secondary batteries (B11, B12) are fully charged. When the battery pack (B2) is charged, the switching elements (Q22, Q11) are turned off and the switching element (Q21) is turned on until the secondary batteries (B21, B22) are fully charged.