Novel concept design of low energy hybrid battery thermal management system using PCM and multistage Tesla valve liquid cooling

To challenge the continuous operation performance of high energy density lithium-ion batteries at different ambient temperatures. A battery thermal management system combining Multi-stage tesla valve liquid cooling and Phase change material (MP) is proposed. After verification of the accuracy of the thermal model based on experimental measurements, numerical studies are performed at the end of 2C rate discharge. In addition, based on general full factorial design method, Kriging approximation model is used to construct complex nonlinear hybrid model between the spacing between batteries, the number of MSTV channels, coolant velocity and the performance of MP (pressure drop, standard deviation of surface temperature, and maximum temperature). At the same time, to avoid falling into local solutions, the adaptive simulated annealing (ASA) global search algorithm is integrated to optimize high-dimensionality multi-objective structural settings. The simulation results show that the designed MP-BTMS is connected with water/ethanol coolant and the inlet velocity is 0.193 m/s, the maximum temperature, standard deviation of surface temperature and pressure drop of the battery pack at 33.12 °C, 1.50 ℃ and 647.8 Pa, respectively. Finally, the optimised MP is used in continuous depth discharge conditions, as well as a range of simulation tests. The superiority of the optimum battery thermal management system in different application scenarios (liquid cooling/heating) is also verified. The cooling performance indicates that the use of MP reduces the total energy consumption required for coolant circulation by 79.9% compared to conventional BTMS. Moreover, it is found that at ambient temperature (Tamb = -10 °C), the use of MP can keep the battery module warm twice as long compared to conventional BTMS. This means that MP can significantly delay the temperature drop during cold stops of EVs, thus reducing the energy required for active battery heating after short-term parking.