Detailed explanation of the necessity and development trend of thermal management of power lithium battery packs

The safety issues of lithium battery packs, especially the foresight of battery thermal management, seem to have not attracted enough attention. As the temperature decreases, the discharge performance of the lithium battery pack decreases significantly, the discharge platform is clearly reduced, and the discharge capacity is clearly reduced. When the temperature drops to -30°C, the discharge capacity of the lithium battery pack is 87.0% of the room temperature discharge capacity. When used in a low temperature environment for a long time, or in an ultra-low temperature environment of -40°C, the power supply will be frozen and cause permanent damage. Therefore, thermal management of lithium battery packs is particularly necessary. Currently, there are two methods for low-temperature heating of lithium batteries. One is variable resistance heating, including PTC heating plate and carbon film heating plate; the other is constant resistance heating, which contains silica gel heating plate, PI heating film, and epoxy plate. Heat the film. Test data shows that after the energy-type lithium battery pack is charged at 1C for 45 minutes in an adiabatic environment, the temperature rise inside the battery cell is above 10 degrees Celsius, and some even above 15 degrees Celsius. The test of a fully charged battery cell shows that in an adiabatic environment, when the battery is heated to 50 degrees with an external source, there will be self-reaction inside the battery core, and the temperature will start to rise. Although the rise is slower, the final result is combustion. Invalidate. Therefore, the electric vehicle power lithium battery pack system must do a good job of thermal management. In the early days of electric vehicles, if there is no effective thermal management, as the service life increases, the probability of a safety accident during fast charging in summer will increase a lot. In recent years, while responding to the needs of users to increase the mileage of cars and thereby increase battery energy density, it has also increased potential safety hazards. Starting in 2017, the specific capacity of the system has been increased from 85 Wh/kg to 140 Wh/kg, and it is expected to increase next year. At the market level, my country’s total production of new energy vehicles is expected to exceed 1 million this year. As the scale of ownership exceeds 2 million, safety issues will be particularly prominent. Regarding the future development trend of thermal management of lithium battery packs, the author believes that the water-cooling mode will become the mainstream use. Install the water-cooling plate on the side or bottom of the battery, connect with the condenser through the inlet and outlet pipes, and take away the heat through the fluid flow to dissipate the heat of each battery. Important products include electric heating plates, electric heating films, silicone rubber heaters, oil drum heaters, Kapton heaters, silicone rubber heating plates, silicone rubber wires and cables, instrument insulation pipes and electric heating cables, etc. The market scope covers new energy vehicles , Semiconductor, medical, aerospace, power and other industries. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the charging methods for lithium batteries to maintain their life?