| 摘要 |
PROBLEM TO BE SOLVED: To discharge gas through an opening of relatively small area made in the center of the bottom of a case by making an explosion-proof groove relatively thick at a part close to the outer circumference of the bottom of the case and making it thin in the vicinity of the center. SOLUTION: An electrolytic capacitor element 1 is encased in an aluminum case 2 having an opening sealed hermetically with an elastic sealing body 3. Leads 4 extend from the capacitor element 1 through the sealing body 3 to the outside. Four explosion-proof grooves 6 are made in the outer surface at the bottom 5 of a case from the central part toward the outer circumferential part thereof. The explosion-proof groove 6 comprises a deep groove part 6a in the vicinity of the center and a shallow groove part 6b on the outer circumferential side arranged stepwise. Consequently, fluctuation of internal pressure causing fracture of the explosion-proof groove 6 is suppressed, explosion-proof operation is stabilized, an opening occurring at the time of explosion-proof operation is decreased and the capacitor element 1 in the case 2 is prevented from being scattered to the outside.
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