Abstract: A battery controller 10 outputs a voltage sampling and holding command signal to an integrated circuit CCn located at an upstream end of cascade connection of integrated circuits CC1-CCn such that integrated circuits CC1-CCn sample and hold output voltages of unit cells 1 grouped into battery modules M1-Mn. The battery controller 10, after transmission of the voltage sampling and holding command signal, outputs a transmission command signal to the integrated circuit CCn at the upstream end of the cascade circuit to transmit output voltages of the unit cells 1 held in the integrated circuits CC1-CCn to the battery controller 10. As a result, a time lag in the detection timings of output voltages of the unit cells 1 of the battery modules M1-Mn can be decreased.

Abstract: Even when temperature sensors (12, 13) used in a device for warming a battery (1) being not in use by using a battery-driven heater (2) have failed, the battery (1) is prevented from freezing. Based on a battery temperature (Tb) and an outside air temperature (Ta), times (?t1 to ?t8) during which Tb will decrease down to a warming start temperature (Tb_start) are each set to the next controller startup time (?t). A controller (9) is started up every ?t, at t2, t3, and t4, and checks whether Tb<Tb_start is satisfied or not. At t4 when Tb<Tb_start is satisfied, a heater (2) is battery-driven to warm the battery (1). After t0 when the outside air temperature sensor (13) fails, the outside air temperature (Ta) is set to a fixed value (Ta_const) and based on this Ta=Ta_const and the battery temperature (Tb), the above control is repeated.

Abstract: Even when temperature sensors (12, 13) used in a device for warming a battery (1) being not in use by using a battery-driven heater (2) have failed, the battery (1) is prevented from freezing. Based on a battery temperature (Tb) and an outside air temperature (Ta), times (?t1 to ?t8) during which Tb will decrease down to a warming start temperature (Tb_start) are each set to the next controller startup time (?t). A controller (9) is started up every ?t, at t2, t3, and t4, and checks whether Tb<Tb_start is satisfied or not. At t4 when Tb<Tb_start is satisfied, a heater (2) is battery-driven to warm the battery (1). After t0 when the outside air temperature sensor (13) fails, the outside air temperature (Ta) is set to a fixed value (Ta_const) and based on this Ta=Ta_const and the battery temperature (Tb), the above control is repeated.

Abstract: A battery controller 10 outputs a voltage sampling and holding command signal to an integrated circuit CCn located at an upstream end of cascade connection of integrated circuits CC1-CCn such that integrated circuits CC1-CCn sample and hold output voltages of unit cells 1 grouped into battery modules M1-Mn. The battery controller 10, after confirming that the voltage sampling and holding command signal has been transmitted to an integrated circuit CC1 located at a downstream end of the cascade connection, outputs a transmission command signal to the integrated circuit CCn at the upstream end of the cascade circuit to transmit output voltages of the unit cells 1 held in the integrated circuits CC1-CCn to the battery controller 10. As a result, a time lag in the detection timings of output voltages of the unit cells 1 of the battery modules M1-Mn can be decreased.