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The performance and life of Li-ion battery packs for electric vehicle (EV), hybrid electrical vehicle (HEV), and plug-in hybrid electrical vehicle (PHEV) applications are influenced significantly by battery operation temperatures. Thermal management of a battery pack is one of the main factors to be considered in the pack design, especially for those with indirect air or indirect liquid cooling since the cooling medium is not in contact with the battery cells. In this paper, thermal behavior of Li-ion pouch cells in a battery system for PHEV applications is studied. The battery system is cooled indirectly with liquid through aluminum cooling fins in contact with each cell and a liquid cooled cold plate for each module in the battery pack. The aluminum cooling fins function as a thermal bridge between the cells and the cold plate. Cell temperature distributions are simulated using a finite element analysis approach under cell utilizations corresponding to PHEV applications.

The battery packs for plug-in hybrid electrical vehicle (PHEV) applications are relatively small in the charge depleting (CD) mode but fairly large in the charge sustaining (CS) mode for their duties in comparison to the battery packs for hybrid electrical vehicle (HEV) applications. Thus, the heaviest battery thermal load for a PHEV pack is encountered at the end of the CD mode. Because the cells in PHEV battery packs are generally larger than those in the HEV packs in both capacity and size, control of the maximum cell temperature and the maximum differential cell temperature for the cells in a PHEV pack with high packing efficiency is a challenge for the cooling system design. The maximum cell temperatures locate in the areas near the terminal tabs where the current densities are highest.

The objective of this study is to design efficient epoxy structural foam reinforcements to improve the energy absorption of front and rear automotive bumper beams. Three bumper structural performance criteria were studied. The 64 KPH Front Pole Test criteria was studied to improve energy absorption early in the crash event to facilitate earlier air bag crash pulse detection; thereby reducing air bag firing time. The 16 KPH Rear Thatcham Crash Test was studied to improve energy absorption of the rear bumper system. Improvement in energy absorption will lead to a reduction in intrusion of the Thatcham Rear Moving Barrier into the rear of the vehicle; thereby reducing vehicle repair cost. The 8 KPH Rear Pole Test was also studied to increase energy absorption; thereby reducing intrusion of the rear pole into the vehicle structure and reducing repair cost.