A battery assembly including a housing having a first coolant port and a second coolant port includes a valve assembly fluidically connected to one of the first coolant port and the second coolant port, a pump fluidically connected to the valve assembly and the battery assembly, and a coolant controller operatively connected to the pump and the valve assembly. The coolant controller is operable to control the valve assembly to pass a flow of coolant into the one of the first coolant port and the second coolant port for a first time period and to pass the flow of coolant into the other of the first coolant port and the second coolant port for a second time period.