Cell stack device, module, and module housing device

A cell stack device comprising:

• a cell stack constituted by arraying and electrically connecting cells;
• and
• a pair of conductive members respectively located at two ends of the cell stack in an array direction of the cells and electrically connected to the cells,
• each of the pair of conductive members comprising
• a power receiving portion facing the cell stack, and
• a current extraction portion extending from the power receiving portion,
• the current extraction portion comprising an extraction portion body and a connecting portion to be connected to an external device,
• wherein when a direction in which the current extraction portion extends from the power receiving unit is defined as a first direction, the current extraction portion has a length in the first direction, and when a direction orthogonal to the first direction is defined as a second direction, the current extraction portion has a width in the second direction, the extraction portion body comprises a first part having a shortest width in the second direction shorter than the width of the current extraction portion and a length in the first direction shorter than an average length of the extraction portion body in the first direction.