| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a battery pack device capable of highly accurately detecting a state of charge in a stable output characteristic area having small voltage fluctuation relative to change of SOC. <P>SOLUTION: A battery pack device 200 comprises at least: multiple secondary batteries 10 having a charge characteristic including a small change area where a voltage change width relative to SOC (state of charge) is equal to or under a predetermined value; and an arithmetic unit 42 for calculating the SOC of the secondary batteries 10, using a voltage and a current detected for the secondary batteries 10, when the secondary batteries 10 are charged. When charging is performed in the small change area and a time rate of change of the voltage exceeds a predetermined threshold value for a predetermined period of time, the arithmetic unit 42 determines the SOC of the secondary batteries 10 to be a prescribed value of the SOC beforehand associated with the predetermined threshold value. <P>COPYRIGHT: (C)2012,JPO&INPIT |
