| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery pack capable of easily detecting expansion of a secondary battery while cost is reduced. SOLUTION: The battery pack is provided with a secondary battery 3, a case 2 housing the secondary battery 3, an expansion detecting part 4 arranged between an inner wall of the case 2 and the secondary battery 3 for detecting pressure added by the inner wall of the case 2 and the secondary battery 3, and an abnormality detecting part 532 for detecting abnormalities of the secondary battery 3 when the pressure detected by the expansion detecting part 4 exceeds pressures P1, P3. Then, the expansion detecting part 4 is filled with a material capable of deforming by pressure between electrodes 41, 42 set in opposition, and as a conductive filler 44 with an electric resistance smaller than the material is retained in dispersion in the material, a resistance value is more decreased as the pressure added between the electrodes 41, 42 is more increased. The abnormality detecting part 532 obtains the resistance value between the electrodes 41, 42 as information showing the pressure. COPYRIGHT: (C)2009,JPO&INPIT
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