Optimization, Modelling and Analysis of Air-Cooled Battery Thermal Management System for Electric Vehicles

Electric Vehicles (EVs) are the need of the hour due to growing climate change problems linked with the transportation sector. Battery Thermal Management System (BTMS), which is accountable for certifying safety and performance of lithium-ion batteries (LiB), is the most vital part of an EV. LiB has auspicious gravimetric energy density but the heat generation due to chemical reactions inside a LiB during charging and discharging causes temperature rise which has a direct effect on LiB performance and safety. This study specifically focuses on aircooled BTMS, defines different types of air-cooled BTMS (active and Passive), discusses limitations associated with air-cooled BTMS, and investigates different optimization techniques and parameters to improve performance of air-cooled BTMS. Maintaining temperature within optimum range and uniform temperature distribution between cells of a battery pack are the major design parameters for improving the performance and efficiency of air-cooled BTMS. Various optimization techniques including cell arrangement with a battery pack, air-flow channel optimization, and air inlet/outlet position variations are discussed and each technique is thoroughly reviewed. Finally, it’s noted that passive air-cooled BTMS is not that effective for long-distance vehicles so most researchers shifted their focus toward active air-cooled BTMS. Active air-cooled BTMS requires a lot of power for effective performance. Lastly, the most recent field of air-cooled BTMS technology which is Air-Hybrid BTMS is discussed and declared a very promising solution for overcoming major limitations associated with air-cooled BTMS.

Optimization, Modelling and Analysis of Air-Cooled Battery Thermal Management System for Electric Vehicles

Electric Vehicles (EVs) are the need of the hour due to growing climate change problems linked with the transportation sector. Battery Thermal Management System (BTMS), which is accountable for certifying safety and performance of lithium-ion batteries (LiB), is the most vital part of an EV. LiB has auspicious gravimetric energy density but the heat generation due to chemical reactions inside a LiB during charging and discharging causes temperature rise which has a direct effect on LiB performance and safety. This study specifically focuses on aircooled BTMS, defines different types of air-cooled BTMS (active and Passive), discusses limitations associated with air-cooled BTMS, and investigates different optimization techniques and parameters to improve performance of air-cooled BTMS. Maintaining temperature within optimum range and uniform temperature distribution between cells of a battery pack are the major design parameters for improving the performance and efficiency of air-cooled BTMS. Various optimization techniques including cell arrangement with a battery pack, air-flow channel optimization, and air inlet/outlet position variations are discussed and each technique is thoroughly reviewed. Finally, it’s noted that passive air-cooled BTMS is not that effective for long-distance vehicles so most researchers shifted their focus toward active air-cooled BTMS. Active air-cooled BTMS requires a lot of power for effective performance. Lastly, the most recent field of air-cooled BTMS technology which is Air-Hybrid BTMS is discussed and declared a very promising solution for overcoming major limitations associated with air-cooled BTMS.

Thermal Performance of a Cylindrical Lithium-Ion Battery Module Cooled by Two-Phase Refrigerant Circulation

It is important for the safety and good performance of a Li-ion battery module/pack to have an efficient thermal management system. In this paper, a battery thermal management system with a two-phase refrigerant circulated by a pump was developed. A battery module consisting of 240 18650-type Li-ion batteries was fabricated based on a finned-tube heat-exchanger structure. This structural design offers the potential to reduce the weight of the battery thermal management system. The cooling performance of the battery module was experimentally studied under different charge/discharge C-rates and with different refrigerant circulation pump operation frequencies. The results demonstrated the effectiveness of the cooling system. It was found that the refrigerant-based battery thermal management system could maintain the battery module maximum temperature under 38 °C and the temperature non-uniformity within 2.5 °C for the various operation conditions considered. The experimental results with 0.5 C charging and a US06 drive cycle showed that the thermal management system could reduce the maximum temperature difference in the battery module from an initial value of 4.5 °C to 2.6 °C, and from the initial 1.3 °C to 1.1 °C, respectively. In addition, the variable pump frequency mode was found to be effective at controlling the battery module, functioning at a desirable constant temperature and at the same time minimizing the pump work consumption.