Power storage device, electrode terminal unit, and exterior body set

An electrical storage device comprising:

• an electrode assembly;
• an outer packaging sealing the electrode assembly;
• and
• an electrode terminal having one end part and other end part disposed along a first direction, the one end part being connected to the electrode assembly, the other end part protruding to an outside of the outer packaging, and the electrode terminal being composed of a first material, wherein
• the outer packaging has a fixing member fixed to the electrode terminal along a second direction intersecting the first direction between the one end part and the other end part of the electrode terminal and composed of a second material different from the first material, and
• when a Vickers hardness of the first material is designated as h (HV), a thickness of the electrode terminal along a direction orthogonal to the first direction and the second direction is designated as T (mm), a linear expansion coefficient of the first material is designated as α1, a linear expansion coefficient of the second material is designated as α2, and a length of the electrode terminal fixed to the fixing member along the second direction is designated as L0 (mm),
• (h×T)2×(α1/α2)=L0≥0.222 is satisfied.