POWER STORAGE DEVICE

PROBLEM TO BE SOLVED: To provide a power storage device which is capable of improving the effect of preventing leakage of a nonaqueous electrolyte inside the power storage device with a simple configuration when discharging a gas generated inside the power storage device, exhibits less reduction in capacitance, and is excellent in long-term reliability.SOLUTION: The power storage device includes exterior film materials 2 which enclose an electrode body 1 and airtightly seal it by a heat-welded part 20. The heat-welded part 20 is formed by superposing the exterior film materials 2 on each other and performing heat welding. The power storage device also includes: a porous film 3 which is interposed between the exterior film materials 2 in a part of the heat-welded part 20 and whose one end is exposed from the heat-welded part 20 toward the electrode body 1; and a hole 4 provided in the exterior film materials 2 so as to face to the porous film 3. The gas generated inside the power storage device enters the porous film 3 from the exposed one end of the porous film 3, reaches the hole 4 provided in the exterior film materials 2, and is discharged from the hole 4 to the outside of the power storage device. 【課題】蓄電デバイス内部で発生したガスを放出する際に、蓄電デバイス内部の非水電解液の漏出防止効果を簡単な構成で向上させることができ、静電容量の低下の少ない長期信頼性に優れた蓄電デバイスを提供する。【解決手段】蓄電デバイスは、電極体１を内包して熱溶着部２０により気密に封止する外装フィルム材２０を備え、熱溶着部２０は外装フィルム材２同士を重ね合わせて熱溶着により形成される。また、熱溶着部２０の一部において外装フィルム材２同士の間に介在するとともに一端が電極体１に向かって熱溶着部２０から露出する多孔質フィルム３と、多孔質フィルム３に対向して外装フィルム材２に設けられる孔４とを備える。蓄電デバイス内部で発生したガスは、多孔質フィルム３の露出する一端から多孔質フィルム３内に侵入し、外装フィルム材２に設けた孔４に到達し、孔４から蓄電デバイスの外部に放出される。【選択図】図１