To greatly shorten a time required for a deterioration degree judgement and a residual capacity measurement of a battery.
In a judging method of a deterioration degree of a battery of such a type that an electrode is deposited and dissolved, a rectangular wave current is applied in advance to plural batteries whose deterioration states are different and known, respectively, in the fully charged state, and the change of the battery voltage with the passage of time by the rectangular wave current at the charging and discharging time of the battery is measured corresponding to the deterioration state and preserved as a table 16. A rectangular wave current is applied to a battery 5 to be measured from a power source 2, and the change of the battery voltage with the passage of time shown at that time is compared with the change with the passage of time preserved in the table 16, and the deterioration state of the battery is judged by the corresponding change with the passage of time, to thereby judge the battery deterioration degree.
ADACHI KAZUYUKI
TOYOFUKU TOSHIJI
TANAKA YOSHIHIRO
