POWER SUPPLY DEVICE, VEHICLE EQUIPPED WITH POWER SUPPLY DEVICE, ELECTRICITY STORAGE DEVICE, AND METHOD FOR DETECTING STATE OF CHARGE OF BATTERY

摘要

[Problem] To more accurately detect the state of charge of a battery. [Solution] A power supply device comprises a battery (22) to be charged and discharged, a current detection unit (16), a voltage detection unit (12), and a state-of-charge calculation unit (18). The state-of-charge calculation unit (18) includes: a first calculation unit (41) for calculating a first open terminal voltage (Voc1) from a plurality of current values and voltage values input from the current detection unit (16) and the voltage detection unit (12) and detecting a first state of charge from the first open terminal voltage (Voc1); a second calculation unit (42) for calculating a second open terminal voltage (Voc2) from the input current and voltage values, a voltage drop (Vo) across the ohmic resistance value (Ro) of the battery, and a voltage drop (Vp) across a polarization resistance value (Rp) and detecting a second state of charge from the calculated second open terminal voltage (Voc2); and a third calculation unit (43) for calculating a third state of charge by adding up the current values of the battery. From either or both of the first state of charge and the third state of charge and the second state of charge, a main calculation unit (40) detects the real state of charge of the battery to be charged and discharged.