Design And Optimization Of Battery Module Heat Dissipation Structure For Electric Sanitation Vehicles

Promote the transformation of the fuel vehicle into electric vehicle is of positive significance to alleviating human energy crisis,environmental pollution,and climate warming.By compared with passenger vehicles,sanitation vehicles are always used in a more stable working environment and better charging conditions.Therefore,the electrification of sanitation vehicles has advantages of great feasibility and high promotion value.The battery pack is one of the core component of the electric sanitation vehicle.Excessive temperature inside the battery pack can lead to the battery thermal runaway even vehicles explode.The inconsistency among the battery cells can lead to different heating rate and temperature between the batteries,which can cause the decline of performance and safety of the battery system.Therefore,the battery thermal management system must be able to effectively reduce the maximum temperature Tmax and the maximum temperature difference AT between the battery packs.Designing and optimizing the heat dissipation structure of the power battery is of great significance to improving the battery life,performance and safety of the electric vehicle.The main contents are as follows:(1)Battery and heat-removal system are determined.Firstly,this article has analyzed the feature of lithium-ion batteries commonly used in the market.Then,the Iron phosphate-lithium power battery has been selected as the power battery for the sanitation vehicle.Through the analysis and comparison of common battery thermal management systems,air cooling has been selected as the cooling mode of the heat dissipation structure for electric vehicles battery module.(2)Battery temperature characteristics are tested and battery thermal model are established.In order to investigate the effect of temperature on the discharge capacity and internal resistance of the Iron phosphate-lithium power battery,the temperature characteristics of the battery cells have been tested in this paper.The obtained temperature performance curve has been used for the establishment and verification of finite element modeling of the lithium iron phosphate battery.(3)The evaluation and screening of battery in terms of consistency.This article has also conducted a consistency screening of the selected lithium iron phosphate batteries.The selected ten battery cells are synthesized into a module for module experiments.The CFD model of battery module has been established.And the validity of battery module CFD model has been verified by comparing the temperature rise curve of the battery surface under 1C and 1.5C discharge rate,Which was obtained by means of the CFD method and the experimental method.(4)The structural parameters of heat removal system is optimized.By means of the control factor method,through the CFD simulation calculation,the influence of different inlet and outlet spoiler angle of the battery box and different layout of the battery cell gap on the temperature control effect and power consumption of the battery thermal management system has been investigated In terms of the simulation data,by means of the header design of the orthogonal test,the influence of four design variables and the interaction between them on the temperature control effect and power consumption of the battery thermal management system has been investigated.The optimal level of each variable has been obtained with the range analysis method.Compared with the pre-optimized battery thermal management sysytem,the maximum temperature of the battery surface within the battery module and the maximum surface temperature difference of the battery cells have been significantly reduced,after designing and optimizing of the battery thermal management system.when the battery module is discharged on a largest rate at room temperature,the battery can be sustained at a suitable operating temperature and the temperature difference between the cells is acceptable.The pressure drop between the module inlet and outlet has been reduced to some extent,and the power consumption of the battery thermal management system has been effectively reduced.