A vehicle traction battery assembly including an array of stacked prismatic can cases and a support structure is provided. Each of the can cases may define a cavity to receive a battery cell and a multi-prong comb-shaped base. The support structure supports the cases. The support structure and the base define channels therebetween configured for coolant to pass therethrough. A lower portion of each of the can cases open to the channels may be of a dielectric material. A dielectric layer may span a length of the can cases and may be located above the channels. Each of the can cases may define a first locating feature sized to integrate with a second locating feature of an adjacent can case to align the can cases.