The performance and longevity of Li-ion batteries in electric vehicles are significantly influenced by the cell temperature. Hence, efficient thermal management techniques are essential for battery packs. Simulation based optimization approaches improves the efficiency of the battery pack thermal management during the early stage of product development.
In this paper, a simulation-based methodology has been introduced to increase the heat transfer from/to coolant via cooling plate as well as to reduce the heat transfer from/to the external environment. The heat transfer coefficient between cooling plate and coolant needs to be enhanced to achieve efficient heat transfer through cooling plate, without exceeding the coolant pressure drop the target limit. A one-dimensional simulation methodology described in this work analyzed numerous design of experiments for coolant layout without performing CAD iteration loops and optimized the cooling channel width, height and number of channels to maximize the heat transfer coefficients within the pressure drop target. A reduction of 30% in pressure drop and 36% energy saving in coolant pump along with 10% enhancement in heat transfer effectiveness has been achieved with this method.
This study also evaluated the sensitivity of each housing surface in heat transfer to external ambient. Simulation results provided recommendations for thermal insulation at minimum number of surfaces with thermal conductivity and thickness guidelines which gives maximum effectiveness at minimum material addition and cost.
In the final part of this work, both the solutions have been integrated into the battery pack and compared with the baseline for energy consumption. A standstill parking condition at different low ambient conditions for different durations has been considered and energy consumption for pre-heater circuits has been evaluated. Results show that the energy consumption for pre-heater circuits was reduced by at least 31% to a maximum of 84% for the parking duration of 48 hours and 8 hours cases respectively. Thus, the simulation based integrated approach of two solutions helps to design energy efficient battery thermal systems during the design stage for Electric vehicles.