A traction battery cell assembly including a battery cell and a cell case is provided. The cell case defines a cavity sized for receiving the battery cell and includes an inner wall, an outer wall, and a plurality of support chambers disposed between the inner wall and the outer wall. Each of the support chambers defines a polygon having multiple sides. The sides are arranged with one another to define an agent cavity to house neutralizing agent. The plurality of support chambers is arranged with the inner wall and the outer wall such that an impact to one of the walls causes a puncture to one of the sides of the support chambers releasing the neutralizing agent. Each of the support chambers may include five or more sides and adjacent sides may define an angle therebetween greater than ninety degrees.