To provide a battery device charging system that keeps SOC from readily lowering and wastes no power even if there are any batteries having a lower battery capacity.
The battery device charging system for controlling charging of a battery device 10 comprising batteries B1-B3 connected in series includes: switches Sa1-Sa3 for connecting the batteries B1-B3 in series; switches Sb1-Sb3 connected to a bypass line BL bypassing the batteries B1-B3; and an ECU 20 for detecting states of the batteries B1-B3 and controlling the switches Sa1-Sa3, Sb1-Sb3 in accordance with the detected states. The ECU 20 selects batteries not to be charged on the basis of the detected states of the batteries B1-B3, turns the switches Sa1-Sa3 and the switches Sb1-Sb3 pertinent to the batteries off and on, respectively, to bypass the batteries, and charges the other batteries.
ENDO HIDEKI
MATSUBARA JOJI
WATANABE MASANORI
Tadahiro Mitsuishi
Mitsuishi Shunpei
Yasuyuki Tanaka
Hiroshi Matsumoto