Lithium battery manufacturers to talk about the lithium-ion power battery pack thermal problems. Temperature abnormalities will have a huge impact on the performance and life of the power lithium-ion battery pack, and may even occur thermal runaway and other safety problems, so the thermal performance of the power battery pack has a high research value. This paper focuses on the thermal problems of lithium-ion batteries and the design of heat dissipation structure.
Li-ion battery manufacturers to discuss the thermal problems of lithium-ion power battery pack
The heat dissipation of lithium-ion power battery pack has always been one of the key technologies in the industry. Lithium-ion batteries have higher energy density and greater charge/discharge rate than traditional lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, etc., so they generate serious heat during operation.
Especially when applied to the field of power batteries, the road conditions are complex and the environment is harsh (especially in the high temperature summer), the battery heat production is more intense, which has a more significant impact on the battery capacity, life, and especially the safety performance.
To some extent, the safety of lithium-ion batteries is actually its thermal problem, the battery heat generation rate is greater than the rate of heat dissipation, the battery pack will heat up, once the temperature threshold of the battery pack can withstand, the electric equipment will be a serious safety accident, so the heat dissipation of lithium-ion power battery pack is critical.
Lithium-ion power battery pack will generate a certain amount of heat in the process of charging and discharging, especially in the process of high current charging and discharging will generate a lot of heat inside the lithium-ion battery, but due to the structural characteristics of the lithium-ion battery in different directions there are significant differences in thermal conductivity, the thermal conductivity in the direction parallel to the pole piece is significantly higher than the thermal conductivity perpendicular to the pole piece direction, so different ways of heat dissipation not only in the There is a significant difference in efficiency.
Two ways of heat dissipation for new energy vehicle power lithium battery pack
Power battery pack air-cooled structure heat dissipation method
1、Add a cooling fan at one end of the battery pack and leave a ventilation hole at the other end to speed up the air flow between the gaps of the battery cells and take away the high heat generated by the battery cells when they are working.
2、Add thermal conductive silicone gaskets at the top and bottom of the electrode, so that the heat not easily dissipated at the top and bottom can be conducted to the metal shell through TIF thermal conductive silicone film to dissipate heat, while the high electrical insulation and puncture resistance of the silicone film has a good protective effect on the battery pack.
● Power battery pack liquid cooling structure heat dissipation method
1、The heat of the electric cell is transferred to the liquid cooling tube through the heat-conducting silicone film, and the heat is taken away by the free circulation flow of the coolant thermal expansion and contraction, so that the temperature of the whole battery pack is unified, and the strong specific heat capacity of the coolant absorbs the heat generated by the working of the electric cell, so that the whole battery pack operates within the safe temperature.
2、The good insulating performance and high resilience of the thermally conductive silicone film can effectively avoid the problem of vibration and friction breakage between the cells, and the hidden danger of short circuit between the cells, which is the best auxiliary material for the water cooling solution.
The importance of power battery thermal management
At present, most of the power batteries are lithium-ion batteries, and lithium-ion batteries are prone to thermal runaway caused by chain exothermic reactions in the case of overcharging, pinching and collision, resulting in serious accidents such as smoke, fire and even explosion. Moreover, the performance of the power battery, including energy density, service life, discharge rate, etc., is greatly affected by temperature, so battery thermal management technology is one of the core technologies of new energy vehicles.
In order to improve the safety of the power battery and avoid or inhibit the occurrence of thermal runaway. Overall, the solution to the problem of thermal runaway of lithium-ion batteries needs to be carried out from two aspects: external protection and internal improvement.
The battery thermal management system is a management system used to ensure that the battery system works within the appropriate temperature range from the perspective of making, and is mainly composed of heat-conducting media, measurement and control units and temperature control equipment.
The lithium-ion power battery pack produces a serious temperature gradient inside the battery, which affects the distribution of the current inside the battery, and then leads to inconsistent decay inside the battery, which seriously affects the service life of the lithium-ion battery. Lithium-ion power batteries can operate efficiently and safely within 25℃~40℃, which requires an efficient thermal management system to ensure the operational safety of lithium-ion power battery packs.
If you have any demands in batteries, please feel free to contact info@manlybattery.com
