| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a battery having constitution capable of easily looking over optical properties of an excess electrolyte of a lithium ion secondary battery, a battery system capable of detecting the lithium salt concentration of the excess electrolyte, and a battery system capable of limiting internal resistance in the appropriate region by recovering the deterioration of the battery by suppressing and decreasing increase in the internal resistance of the battery by detecting the lithium salt concentration of the excess electrolyte. <P>SOLUTION: A lithium ion secondary battery 10 includes a power generation element 1 containing a positive electrode 2, a negative electrode 3, and a separator 4 interposed between them; an electrolyte 9 impregnated in the power generation element 1 and containing lithium ions, and a battery case 7 housing the power generation element 1 and the electrolyte 9, and the electrolyte is composed of a holding electrolyte 9A impregnated and held in the power generation element 1 and an excess electrolyte 9B stored in the battery case 7 in a state capable of conducting mutual circulation with the holding electrolyte 9A. The battery case 7 includes a pair of light transmission windows 11A, 11B coming in contact with the excess electrolyte 9B, and arranged so as to be capable of setting an optical path passing through the excess electrolyte 9B. <P>COPYRIGHT: (C)2011,JPO&INPIT |
