A battery system, comprising at least one battery module interconnected between a first system terminal and a second system terminal by a plurality of high current connectors; a housing with a plurality of exterior walls enclosing the at least one battery module and the plurality of high current connectors and with at least one partition wall arranged within the housing; and a battery disconnect unit, BDU, electrically connected between at least one of the first and second system terminal (51, 52) and the at least one battery module, wherein within the housing a flow channel loop is formed by the at least one partition wall and the exterior walls, wherein a gas conveyor configured for providing a gas flow circulation through the flow channel loop and at least one gas sensor configured for detecting an excess concentration of at least one gas species in the gas flow circulation are arranged in the flow channel loop, and wherein the BDU comprises BDU elements (86, 87, 88, 89) configured for selectively disconnecting at least one of the first and second system terminal (51, 52) and the at least one battery module and is disposed within the gas flow circulation such that the BDU elements (86, 87, 88, 89) are cooled by the gas flow circulation, wherein the gas flow circulation is formed to follow a current path between the first and second system terminals (51, 52) by the at least one partition wall, and wherein the BDU comprises a BDU housing enclosing the BDU elements (86, 87, 88, 89) and comprising at least one BDU venting opening connecting the BDU housing interior with the flow channel loop or wherein the BDU elements (86, 87, 88, 89) are disposed unhoused in the flow channel loop formed within the housing. at least one battery module interconnected between a first system terminal and a second system terminal by a plurality of high current connectors; a housing with a plurality of exterior walls enclosing the at least one battery module and the plurality of high current connectors and with at least one partition wall arranged within the housing; and a battery disconnect unit, BDU, electrically connected between at least one of the first and second system terminal (51, 52) and the at least one battery module, wherein within the housing a flow channel loop is formed by the at least one partition wall and the exterior walls, wherein a gas conveyor configured for providing a gas flow circulation through the flow channel loop and at least one gas sensor configured for detecting an excess concentration of at least one gas species in the gas flow circulation are arranged in the flow channel loop, and wherein the BDU comprises BDU elements (86, 87, 88, 89) configured for selectively disconnecting at least one of the first and second system terminal (51, 52) and the at least one battery module and is disposed within the gas flow circulation such that the BDU elements (86, 87, 88, 89) are cooled by the gas flow circulation, wherein the gas flow circulation is formed to follow a current path between the first and second system terminals (51, 52) by the at least one partition wall, and wherein the BDU comprises a BDU housing enclosing the BDU elements (86, 87, 88, 89) and comprising at least one BDU venting opening connecting the BDU housing interior with the flow channel loop or wherein the BDU elements (86, 87, 88, 89) are disposed unhoused in the flow channel loop formed within the housing.