Bidirectional heat transfer characteristics of cavity cold plate battery thermal management system: An experimental study

Abstract

Recently, electric vehicles have developed rapidly because of energy shortage and environmental crisis. Due to different working regions, there is a need for thermal compensation and thermal dissipation of power lithium-ion batteries for electric vehicles. Therefore, a cold plate thermal management scheme that can achieve normal working of lithium-ion battery under extreme high and low ambient temperatures is studied to solve the problem that battery cooling and heating systems are separated. First, two dummy batteries are built based on the experimental data of battery cell heat generation. And cold plate heat management experimental system is built. Then, the effects of a new cold plate with simple structure on the temperature of battery thermal dissipation and thermal compensation are studied by experiment. And the bidirectional heat transfer rules of the cold plate heat management system under extreme ambient temperatures are analyzed. The results show that the cold plate can significantly inhibit temperature rise of battery at high discharge rate, and that the safety of battery pack at higher ambient temperatures is enhanced. When coolant temperature is 45 °C, thermal compensation effects of the cold plate system are optimal. The maximum temperature difference of battery increases with the decrease of ambient temperature in thermal compensation experiment. When ambient temperature is −30 °C, the time to reach 20 °C is 411 s. And the maximum temperature difference at the last moment is 5.2 °C. When ambient temperature is greater than −25 °C, the maximum temperature difference at the last moment is lower than 5 °C. This research has great significance in reducing the complexity of battery pack and improving the application scope of liquid cold plate BTMS.