Power storage module

A power storage module comprising:

• a stack formed of a plurality of electrodes stacked each including a current collector and an active material layer formed on the current collector;
• a seal portion formed in the current collectors and cooperating with the current collectors arranged side by side in a stacking direction of the electrodes to define a plurality of internal spaces that accommodates the respective active material layers;
• a plurality of communication holes formed in the seal portion and providing communication between the plurality of internal spaces and an outside;
• and
• a sheet member provided on the seal portion over the plurality of communication holes, sealing the communication holes individually, and cleaved to release internal pressure in the plurality of respective internal spaces to the outside through the corresponding communication holes, wherein
• the sheet member has a plurality of facing portions facing first openings that are located opposite to the respective internal spaces across the plurality of communication holes and a joint portion that is formed in peripheries of the respective facing portions to enclose the first openings and joined to the seal portion,
• the respective facing portions have stress concentrating portions that serve as starting points of the cleaving, and
• cleavage pressure, which is the internal pressure applied to corresponding one of the facing portions when one of the stress concentrating portions is cleaved, is lower than peeling pressure, which is the internal pressure applied to corresponding one of the facing portion when the joint portion is peeled off from the seal portion.