A battery cell that has a supply edge to which an electrolyte solution is supplied and a discharge edge from which the electrolyte solution is discharged has an introduction port that connects with the supply edge and a discharge port that connects with the discharge edge, and includes a plurality of meandering flow paths each of which is serially formed from the introduction port to the discharge port, the plurality of meandering flow paths being arranged in parallel in a widthwise direction. Each of the meandering flow paths has an introduction-side section extending from the introduction port toward a discharge edge side, a turn-back section that is turned back from an end portion on the discharge edge side of the introduction-side section toward a supply edge side, and a discharge-side section reaching the discharge port from an end portion on the supply edge side of the turn-back section.