一种以多孔结构吸附相变材料为冷却介质的锂离子电池组热管理方法OA北大核心CSTPCD

Lithium-ion batteries serve as pivotal power sources for electric vehicles,dictating their performance,cost,and safety.The continuous quest for higher energy densities in these batteries has led to challenges in effective thermal management.Thermal runaway,stemming from factors like material aging and overcharging,poses serious safety risks,making effective thermal management a critical research area in the realm of lithium-ion batteries. Currently,thermal management strategies for lithium-ion batteries are advancing rapidly,with a focus on integrating phase change materials (PCM)with various cooling methods.Despite PCM's benefits,such as its ability to mitigate thermal issues and enhance temperature control,challenges remain,including low thermal conductivity and structural weaknesses.Researchers have proposed innovative solutions,such as combining PCM with heat pipes or water-cooling systems,to maintain optimal operating temperatures and improve temperature uniformity within battery modules.Furthermore,studies have explored the integration of PCM with supportive structures,such as porous materials,to enhance thermal conduction and overall battery performance.However,existing research lacks in-depth analysis of PCM phase change processes and their effects on battery thermal management.Moving forward,there is a need for further investigation into the coupling relationship between PCM and support structures to optimize thermal management and enhance battery efficiency. In this study,a thermal management approach is proposed which utilizes adsorbed PCM with a porous structure as a cooling medium for lithium-ion batteries.Initially,a theoretical analysis of the thermal coupling equation between the porous structure and PCM is conducted to investigate the impact of the porous structure on PCM properties,including heat transfer and latent heat of phase transition.Subsequently,the feasibility and advantages of employing porous structure-adsorbed PCM for the thermal management of lithium-ion batteries are demonstrated based on the results of simulations. Based on the simulation results,the porous adsorption of PCM significantly enhances thermal conductivity and diminishes the temperature gradient within the battery pack compared to using PCM alone as the cooling medium.Specifically,during the initial 0.2 hours of discharging at a 4C current,the maximum temperature decreases by 2.1％.Furthermore,the disparity between the maximum and average temperatures decreases by 45.5％,and the average temperature variance among single cells decreases by 34.1％,resulting in a more uniform temperature distribution across all locations within the battery box.This approach mitigates the heat differentials arising from the phase change process when PCM is used as the sole cooling medium,thereby reducing the risk of thermal runaway due to heat accumulation at the center.Consequently,the porous structure absorbs PCM,enhancing battery pack safety and reducing the potential for thermal runaway.On the other hand,the porous structure effectively reduces the risk of PCM coming into direct contact with the battery pack wall by providing support and encapsulation.This reduces the possibility of leakage.The porous structure helps disperse the stresses and pressures generated during the phase transformation of the PCM,reducing the load on the structure and thereby minimizing the risk of structural collapse.This extends the service life of the material,improving the reliability and durability of the battery pack. Additionally,the porous structure reduces the likelihood of direct contact between the PCM and the battery pack wall by offering a supportive encapsulation structure,thereby limiting the risk of leakage.The porous structure also disperses the stresses and pressures associated with the PCM's phase transformation,thereby reducing the load on the structure.This factor decreases the risk of structural collapse,extends the material's service life,and enhances the battery pack's reliability and durability.