The invention relates to a temperature-controlling device for a battery module, having a flow space (4) which has a multiplicity of spacer elements (11) and is essentially closed. The spacer elements (11) are arranged within the flow space (4) and the temperature-controlling device (3) further has a flow deflection unit (15) which is arranged within the flow space (4) and has a longitudinal direction (16) extending along the flow deflection unit (15) from a first end (24) to a second end (25) of said flow deflection unit (15). The flow deflection unit (15) forms a first side face (17) and a second side face (18) which sides are arranged in the longitudinal direction (16) on opposite sides of the flow deflection unit (15), and wherein at least portions of the first side face (17) and the second side face (18) are arranged directly adjacent to a spacer element (11, 111, 112).