Provided are a battery cell that can be produced efficiently. A frame body of each cell frame of a battery cell includes an inner peripheral recessed portion formed by reducing a thickness of a peripheral portion that surrounds an entire perimeter of the penetrating window so that the peripheral portion has a smaller thickness than other portions of the frame body. A bipolar plate of the battery cell includes an outer peripheral engaging portion that engages with the inner peripheral recessed portion, the outer peripheral engaging portion being a portion having a particular width and extending throughout an entire outer periphery of the bipolar plate. The battery cell includes a disrupting structure that disrupts a leak channel that serves as an escape route for the electrolyte, the leak channel causing the inlet slit and the outlet slit to be in communication with each other and being formed between an outer periphery of the inner peripheral recessed portion and an outer periphery of the outer peripheral engaging portion when the cell frames are viewed from front.