To easily detect a deteriorated cell at a low cost by dividing a set battery consisting of a number of monoblock batteries into a plurality of blocks, and giving an abnormality alarm when the voltage difference of the batteries between the paired blocks with two blocks as a pair.
A set battery is divided into four two-in-one blocks of blocks No.1-4, a voltage line is leaded every block, and voltage comparison is performed between the blocks No.1 and 2, No.3 and 4 as respective pairs. When an abnormal cell is present in the monoblock batteries No. 1 or 2, the output voltage of a comparator No.1 is LOW with Vb>Va, and a photocoupler 4 No.1 is turned ON. The timing of sounding a buzzer No.1 is selected by comparators No.5, 6. When an abnormal cell is produced by a liquid shortage, a voltage drop is caused from the initial stage of discharge, and it can be clearly discriminated from the occurrence of a voltage drop in the discharge end in a general capacity dispersion, and it is required to limit the timing of sounding the buzzer to the discharge initial stage.
NISHIDA KAZUMI
SUZUKI TAKAHIKO
UEDA KIYOSHI
NAKAMURA HIDEJI
DAIHATSU MOTOR CO LTD