An effective thermal management of lithium-ion battery (LIB) packs for maintaining their operating temperature uniformly and in the manufacturers’ allowable range can increase the battery lifespan for electric and hybrid vehicles. For this purpose, two liquid cooling plates with different flow patterns are designed and compared for a commercial prismatic LIB with graphite anode and lithium iron phosphate (LiFePO4) cathode chemistry. The analysis of the cooling plates is accomplished through mathematical modeling and computer simulation. The cooling plates are designed to dissipate the maximum possible heat generation in the battery in normal operation, which is during the continuous discharge at 5C for the typical LIB under study. An experiment is conducted to determine the local heat flux from the battery during discharge at 5C from the state of charge of 0 to 100%. The cooling plates are studied for different flow rates to determine the optimum design parameters and achieving the minimum pressure drop and temperature gradient on the surface of the battery. Overall, this study provides new design of cooling plates for large prismatic LIBs for electric and hybrid electric vehicles, with the ability to dissipate heat and maintain the battery surface temperature less than 25°C.