A sealing part (21) has an outer peripheral point (PI) of the sealing part (21) within a range from 0 degree to 90 degrees around a center point of the sealing part (21) relative to a stacking direction, and that is located at a distance of a first length L1 from the center point. Each point on the outer peripheral line within a first range satisfies L2 ≤ L1, where L2 is a second length that is a distance from the center point to that point. Each point on the outer peripheral line within a second range satisfies L3