Lithium-ion batteries for battery electric vehicles need to be precisely thermo-controlled for maintaining the vehicle performance under strictly hot and cold environments and for preventing the battery aging. In general, battery modules mounted in a battery pack are cooled or warmed up via coolant liquid and the battery cooling structure consisting of a battery module, a cooling plate, thermal interfaces and mounting parts are required to have two major functionalities, sufficient heat transfer performance between the battery module and the cooling plate and the strength reliability of the composed parts against external loads in strict driving scenarios. A new structural analysis methodology was established to predict the vibrational behavior of the battery cooling structure under rough road condition. This analysis, which is a combination of measurements and simulations, consists of three steps, experimental modal analysis, finite element model correlation and transient response simulation. The resonance frequencies and the frequency response functions were measured with the cooling structure components under disassembled and assembled states. Additionally, the viscoelastic characteristics of thermal pads located between the battery module and the cooling plate were empirically acquired. The cooling structure modeled with finite element method was validated in comparison with the measured results. Then, the transient response behavior under vibrational input during driving was predicted using the validated models This paper described developed analysis methodology and the results using the battery pack of the battery electric vehicle released in 2020. As the result, the simulated transient behavior of the battery cooling plate had good correlation to the vibration test results using the battery pack. Moreover, the contact state of heat transfer area between the battery module and the cooling plate under rough road driving condition was predicted through the developed simulation. It was demonstrated that developed analysis and series of work flow had enough accuracy to predict the vibrational behavior of the battery cooling structure and contribute to the structural design and the validation.

Mr. Katsuya Minami, Honda R&D Japan, JAPAN Mr. Hiromichi Ebihara, ESTECH CORP., JAPAN