Board-shaped member and battery stack

A board-shaped member sandwiched between a plurality of power storage modules stacked, the board-shaped member comprising:

• a conductive plate that is disposed between the plurality of power storage modules;
• a battery stack plate that includes a board-shaped insulating housing having a fitting groove recessed in a side face of the board-shaped insulating housing so as to fit with a side edge of the conductive plate;
• a sealing material supply groove respectively provided in front and back faces of the insulating housing along an extension direction of the fitting groove;
• a through hole that communicates with the sealing material supply groove and the fitting groove;
• and
• a sealing material that is pre-filled into the fitting groove and is extruded from the fitting groove to the front and back faces of the insulating housing through the through hole and the sealing material supply groove when the side edge of the conductive plate is fitted into the fitting groove.