Patent ID: 8486561

Claim:
An electrochemical device comprising: an outer package including a metal film; a battery element enclosed in the outer package; resin layers provided at least inside a sealing region of the outer package; and a lead extending from the battery element through between the resin layers in the sealing region of the outer package to the outside of the outer package, wherein: a shape of the lead in the sealing region includes a front surface and a back surface comprising first and second curved surfaces, respectively, which are opposed to each other, a first intersecting line between the first surface and a plane perpendicular to a longitudinal direction of the lead comprising a continuous first curve convex in a direction away from the lead, and a second intersecting line between the second surface and the plane perpendicular to the longitudinal direction of the lead comprising a continuous second curve convex in a direction away from the lead, in the sealing region, a maximum thickness Z 1 (μm) of the lead near a lateral center position of the lead and a thickness Z 11 (μm) at a lateral end position of the lead satisfy the following relational expression Z 11 <Z 1 , and the thickness Z 11 (μm) is not less than 15 (μm).