Design and experimental study of battery thermal management for special vehicles
[Objective]Fire not only poses a threat to the safety of individuals and property but also places firefighters and rescuers at continuous risk.To enhance the ability of firefighters to safely explore fire environments and perform dangerous rescue tasks,special firefighting vehicles have been developed.For these electrically driven vehicles,it is crucial to design a thermal management system for their batteries to ensure safe operation.[Methods]This study introduces a thermal management system design that integrates phase change cooling,liquid cooling,and external thermal insulation.The design incorporates a heat insulation structure around the battery pack to reduce the impact of high-temperature fire environments.At the same time,phase change materials are utilized to absorb and temporarily store heat generated inside the battery pack.After completing the mission and exiting the fire zone,a liquid cooling structure is activated to dissipate the internal heat from the battery pack and solidify the phase change material.This study focuses on managing the temperature of the battery pack using phase change materials.To assess the feasibility of the proposed design,numerical simulations were performed using Fluent software.First,a heat production model for a single 21700-50E lithium-ion battery was established by combining Bernardi's formula and existing experimental data.The reliability of this model was verified experimentally.Subsequently,a simplified simulation model for the battery pack was developed to evaluate its temperature behavior under experimental conditions.The results indicate that the temperature of the battery pack remained within the normal range.Following these simulations,a physical prototype based on the proposed design was fabricated.The prototype underwent charging and discharging tests as well as the temperature rise assessments test.[Results]The test results showed that the battery pack works normally during constant current discharge,with the temperature being effectively controlled through the use of phase change materials.In addition,to further optimize the design,this study explores how the phase change point,latent heat of phase change,and other factors affect the cooling performance of thermal management systems via simulation models.The key findings include the following:1)Under low loads,materials with lower phase change points can initiate phase change earlier,aiding in the reduction of the battery pack's temperature.Among the phase change materials discussed in this study,lowering the phase change point by 2 K can reduce the battery temperature rise by about 7％-13％.2)Thermal conductivity plays a more important role under high load conditions.The data show that increasing the battery pack's thermal conductivity can decrease its maximum temperature by up to 5.7 K.3)The latent heat of phase in the materials should not be too low,or else the phase change cooling performance at the late stage of discharging will be significantly reduced.[Conclusions]Simulations and experimental verification demonstrated that the proposed thermal management system for firefighting special vehicle batteries ensures normal battery operation in nearly adiabatic conditions,maintaining the battery temperature within a reasonable range.In addition,the study on the cooling performance of thermal management shows that measures such as appropriately reducing the phase change point,improving the thermal conductivity of phase change materials,and increasing the latent heat of phase change have a positive effect on reducing the temperature of the battery pack.
special vehicleslithium-ion batteryphase change materialthermal management
万方数据
维普
