Power storage element

A power storage element comprising:

• an electrode winding body provided by winding a first electrode plate and a second electrode plate, each of the first electrode plate and the second electrode plate having a belt shape having a size in a longitudinal direction longer than a size in a width direction,
• the first electrode plate including
• a first current collecting foil,
• a first electrode active material layer disposed on a surface of the first current collecting foil, and
• a separator layer that covers the first electrode active material layer, and the second electrode plate including
• a second current collecting foil, and
• a second electrode active material layer disposed on a surface of the second current collecting foil, a protruding portion in which the second current collecting foil is not covered with the second electrode active material layer being provided at one end in the width direction over an entire length in the longitudinal direction, wherein:
• in the electrode winding body, of ends of the first current collecting foil, the first electrode active material layer, and the separator layer in the width direction, a first end located on a side on which the protruding portion is provided is located outward of a second end in the width direction, the second end being an end of the second electrode active material layer in the width direction located adjacent to the protruding portion;
• in the electrode winding body, an insulating member is interposed between the first electrode plate and the second electrode plate;
• the insulating member is provided in a region including at least the second end and the first end in the width direction;
• and
• the insulating member is provided in a region including a third end of the second electrode plate in the longitudinal direction and a fourth end opposite to the third end in the longitudinal direction, and is not provided in a region between the third end and the fourth end in the longitudinal direction.