Experimental study on the thermal management performance of air cooling for high energy density cylindrical lithium-ion batteries

Highlights: • The thermal performance of aligned, staggered, and cross battery packs is experimentally studied. • The effect of the discharge rate and air inlet temperature on the thermal management system is analyzed. • The energy efficiency of the air cooling battery thermal management system is investigated under various conditions. • The upper limitation for the cooling capacity is demonstrated in this paper. -- Abstract: To comprehensively investigate the characteristics of an air cooling system, a battery pack with 32 high energy density cylindrical lithium-ion batteries is designed in this paper. Using a series of evaluation parameters, the air cooling performances of aligned, staggered, and cross battery packs are experimentally studied and compared at different air inlet velocities. Additionally, the cooling effect and capacity of the air cooling system are investigated by changing the discharge rate and air inlet temperature. Finally, the energy efficiency of the air cooling system under various operating conditions is studied. It is found that the aligned arrangement has the best cooling performance and temperature uniformity, followed by the staggered and finally the cross arrangement. The minimum temperature always occurs in the second column along the direction of the air inlet. The parasitic power consumption increases exponentially with the air inlet velocity, and the aligned arrangement has the lowest power consumption, up to 23% less than that of the cross arrangement. Additionally, the energy efficiency of the air cooling system decreases with the increasing air velocity, and the cooling capacity has an upper limit that is proportional to the discharge rate.