Abstract: A battery module includes a plurality of electrochemical cells arranged in a first row and a second row offset from the first row. The battery module also includes a heat exchanger configured to allow a fluid to flow through the heat exchanger. The heat exchanger is disposed between the first and second rows of cells and has a shape that is complementary to the cells in the first and second rows of cells so that an external surface of the heat exchanger contacts a portion of each of the plurality of electrochemical cells. The heat exchanger is configured to route the fluid between an inlet and an outlet such that a path of the fluid flow includes a plurality of adjacent fluid flow segments.