| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an ininterruptible power supply in which deterioration in lifetime of a lithium ion secondary battery due to overcharge is prevented over the entire use period. <P>SOLUTION: Every time a lithium ion secondary battery 22 is discharged, a discharge time acquiring means 38 counts the discharge time until the voltage across the lithium ion secondary battery 22 drops down to a set voltage. A charge control means 39 performs variable control of next charging voltage of the lithium ion secondary battery 22 such that the discharge time approaches a set time. Since charging voltage of the lithium ion secondary battery 22 is set variably such that the discharge time approaches a set time slightly exceeding the request backup time over the entire use period of the lithium ion secondary battery 22, deterioration in lifetime of the lithium ion secondary battery 22 due to overcharge is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
