Abstract: Promoting new energy vehicles is one of the effective ways to accomplish China’s “carbon peak” and “carbon neutrality” goals and to deal with the global climate crisis. Compared with other types of batteries, such as nickel-metal hydride batteries and lead-acid batteries, lithium ion batteries have the advantages of a high energy density, high efficiency, long life and environmental friendliness, and have been widely used. Therefore, new energy vehicles with lithium ion batteries as the energy system have also evolved rapidly. However, a proper operating environment is the key to ensuring efficient operation of lithium ion batteries. If the environmental temperature is too high, a lithium ion battery may suffer from thermal runaway, which may lead to burning or explosion. If the environmental temperature is too low, charging and discharging performance of a lithium ion battery will be affected, and the surface of the negative electrode is prone to disaggregating lithium and producing dendrites, resulting in capacity decay and even piercing the separator to form an internal short circuit. Therefore, developing an effective thermal management system to make lithium ion batteries operate within a suitable temperature range is the key to ensuring safe and stable operation of new energy vehicles. This article systematically analyzes the existing cooling technologies of lithium ion battery thermal management system and compares their advantages and disadvantages. Lastly, the future development trend of the electric vehicle thermal management system is discussed based on the current development state of the lithium ion battery thermal management system.