What are the important functions of the power lithium-ion battery thermal management system? -Lithium - Ion Battery Equipment
Too high or too low temperature will directly affect the service life and performance of the power lithium-ion battery, and may lead to safety problems of the battery system, and the long-term uneven distribution of the temperature field in the battery box will cause various battery modules, unit The performance of the body is not balanced, therefore, the battery thermal management system is necessary for the electric vehicle power lithium-ion battery system. A reliable and efficient thermal management system is of great significance for the reliable and safe application of electric vehicles.(Lithium - Ion Battery Equipment)
The battery pack thermal management system has the following five important functions:
① Accurate measurement and monitoring of battery temperature.
② Effective heat dissipation and ventilation when the temperature of the battery pack is too high.
③Rapid heating under low temperature conditions.
④Effective ventilation when harmful gases appear.
⑤ Ensure the uniform distribution of the temperature field of the battery pack.
The basic way of heat transfer in the battery
There are mainly three ways of heat transfer in the battery: heat conduction, convective heat transfer and radiation heat transfer.
The heat exchanged between the battery and the environment is also carried out in three ways: radiation, conduction and convection. Thermal radiation mainly occurs on the surface of the battery and is related to the properties of the battery surface material.
Heat conduction refers to the heat transfer that occurs when a substance is in direct contact with an object. The electrodes, electrolyte, current collector, etc. inside the battery are all heat transfer media, and the battery as a whole, the temperature of the interface layer between the battery and the environment and the heat conduction properties of the environment determine the heat conduction in the environment.
Heat convection refers to the exchange of heat on the surface of the battery through the flow of the ambient medium (usually a fluid), which is also proportional to the temperature difference.
As far as the interior of the single battery is concerned, the effects of heat radiation and heat convection are small, and the heat transfer is mainly determined by heat conduction. The amount of heat absorbed by the battery itself is related to the specific heat capacity of its material. The larger the specific heat capacity, the more heat dissipation and the smaller the temperature rise of the battery. If the heat dissipation is greater than or equal to the heat generated, the battery temperature will not rise. If the heat dissipation is less than the generated heat, the heat will accumulate in the battery body and the battery temperature will rise.