When a lithium-ion battery operates in an inappropriate operating temperature range (high temperature, low temperature, excessive temperature difference, etc.), its safety will also be greatly affected, which will seriously affect the safety of electric vehicles. The lithium battery pack is composed of multiple single lithium battery packs connected in series or in parallel. When the battery pack is charging and discharging, when the ambient temperature is too high, the heat generated by the electrochemical reaction of the battery itself cannot be released in time, and the reaction of the lithium ion battery The activity is enhanced, and side reactions may occur inside it, which is prone to thermal runaway and then leads to combustion, producing high-temperature flammable and toxic gases. In addition, the internal circuit structure of the lithium-ion battery pack is complex, and an external short circuit may occur at high temperature, which affects the safety of electric vehicles.
In short, the development of an efficient thermal management system is the key to ensuring the safe and stable operation of new energy vehicles in extreme environments, and it is also the key to achieving larger-scale deployment and promotion.
Battery cooling technology classification:
Classification of lithium-ion battery cooling technologies. According to the characteristics of the cooling method, lithium-ion battery cooling technology can be divided into active cooling and passive cooling. Among them, active cooling technologies mainly include forced convection air cooling, coolant cooling and direct refrigerant cooling, which require additional energy to drive fans or pumps. Passive cooling systems include natural convection air cooling, phase change material cooling, and heat pipe cooling. Passive cooling systems require specific structures on the battery surface to dissipate heat, such as phase change materials or heat pipes. Additionally, passive systems based on phase change materials can also be used to improve temperature uniformity within the battery pack. Compared with the passive cooling system, the active cooling system has better heat dissipation capability, but the structure is more complicated.