A battery module comprising: a battery stack including a plurality of batteries that are stacked, the plurality of batteries including the plurality of valves through which a gas is blown off; the batteries being prismatic, a duct plate configured to cover a surface of the battery stack on which the plurality of the valves are disposed, the duct plate including a gas discharge duct that extends in a stacking direction of the batteries, is connected to the valves of the batteries, and temporarily stores the gas blown off through the valves; a cover plate placed on the duct plate; and a flow path portion defined by the duct plate and the cover plate, the flow path portion extending from the gas discharge duct in a first direction that intersects with the stacking direction of the batteries and allowing leaking of the gas in the gas discharge duct to an outside of the battery module, wherein the first direction is an horizontal direction, flow path outlets connected to the flow path and being disposed at end portions of the battery module in the horizontal direction, and through which gas is discharged, wherein the cover plate is disposed in a state where a predetermined gap is configured between the cover plate and a first wall of the gas discharge duct that faces the valves, so that the first wall and the cover plate are spaced apart from each other in a vertical direction Z by the predetermined gap, and an opening that allows an inside of the gas discharge duct and the predetermined gap to communicate with each other is configured in the first wall of the gas discharge duct, wherein the duct plate includes a pair of second walls that is arranged side by side with the valve sandwiched between the pair of second walls and defines the gas discharge duct together with the first wall, and an opening that allows the gas discharge duct and the flow path to communicate with each other is configured in the pair of second walls respectively. a battery stack including a plurality of batteries that are stacked, the plurality of batteries including the plurality of valves through which a gas is blown off; the batteries being prismatic, a duct plate configured to cover a surface of the battery stack on which the plurality of the valves are disposed, the duct plate including a gas discharge duct that extends in a stacking direction of the batteries, is connected to the valves of the batteries, and temporarily stores the gas blown off through the valves; a cover plate placed on the duct plate; and a flow path portion defined by the duct plate and the cover plate, the flow path portion extending from the gas discharge duct in a first direction that intersects with the stacking direction of the batteries and allowing leaking of the gas in the gas discharge duct to an outside of the battery module, wherein the first direction is an horizontal direction, flow path outlets connected to the flow path and being disposed at end portions of the battery module in the horizontal direction, and through which gas is discharged, wherein the cover plate is disposed in a state where a predetermined gap is configured between the cover plate and a first wall of the gas discharge duct that faces the valves, so that the first wall and the cover plate are spaced apart from each other in a vertical direction Z by the predetermined gap, and an opening that allows an inside of the gas discharge duct and the predetermined gap to communicate with each other is configured in the first wall of the gas discharge duct, wherein the duct plate includes a pair of second walls that is arranged side by side with the valve sandwiched between the pair of second walls and defines the gas discharge duct together with the first wall, and an opening that allows the gas discharge duct and the flow path to communicate with each other is configured in the pair of second walls respectively.