PURPOSE: To provide a secondary battery system with an excellent remaining capacity measuring system which can measure the remaining capacity of a secondary battery at high precision.
CONSTITUTION: A sensor 6 for flowing in current is installed between a primary battery 1 and a secondary battery 3 which is charged by the primary battery 1, a sensor 7 for flowing in and out current is installed between the sensor 6 for flowing in current and the secondary battery 3 and also between the secondary battery 3 and a load 4 which consumes the electric power of the secondary battery 3, and the remaining capacity of the secondary battery 3 is measured based on the detected signals of both sensors 6, 7. Consequently, even if the input current in the primary battery 1 side is low and measurement is carried out for a long duration and the output current is high, the measurement error of the remaining capacity of the secondary battery 3 can be suppressed to the minimum level.
HIGUCHI TANEO
SHIRAI TETSUYUKI
