| 摘要 |
PROBLEM TO BE SOLVED: To provide: a battery pack of lithium ion secondary batteries, in which charge depth thereof can be precisely evaluated without requiring a complicated determination circuit even during charging/discharging with large current; and an electricity storage device.SOLUTION: In a battery pack, a lithium ion battery not for detecting a charge depth and a lithium ion battery for detecting a charge depth, which have an inflection region set to an optional charge depth in advance, are connected in series. By using the battery pack, even during charge/discharge is performed using large current, a charge depth of a whole of the battery pack can be precisely detected when the voltage of an electric cell for detecting a charge depth becomes to charge depth detection voltage. |
