| To cope with the disparities between fuel supply and demand,as well as the environmental pollution,the state has issued a series plans and policies to support the development of pure electric vehicles.High energy density NCM lithium ion batteries are the key parts of electric vehicles,and they are widely used in the field of power batteries because of high endurance performance requirements of the whole vehicle.However,the optimal operating temperature range of lithium ion itself is between 25 and 35 ° C due to its electrochemical system.Therefore,the development of an intelligent and efficient battery thermal management system is a technical problem that needs to be solved by various OEMs,in order to improve the battery's charge and discharge performance,extend its service life,and bring a better driving and use experience to the customers.At this stage,there are many battery thermal management system solutions that need to be improved.However,building a high-precision battery heat generation model based on the battery cell heating mechanism,analyzing the three-dimensional battery package thermal simulation model that is based on the single-model model,describing the thermal field distribution in the battery system,and characterizing the heat transfer mechanism in the system is a critical path and effective method for efficient battery thermal management systems.This paper establishes a module square lithium ion monomer heating model based on the thermal property model parameter identification and hybrid pulse power performance test parameters of square cells.Moreover,the joint modeling based on STRA CCM+,BDS,BSM and GT-SUITE simulation software is completed,the thermal management model is verified and calibrated with the actual measurement results.A practical and feasible analysis and calculation method for the thermal management of pure electric vehicle battery packs and complete vehicles is formed.The main research contents and conclusions of this paper are as follows:The HPPC test data is imported into the BDS software module to establish a cell heating model,and the BDS cell model is introduced into the BSM module of the STRA CCM+.At the same time,a complete battery pack model is set up,and the electrochemical and thermal flow field coupling analysis of the battery pack is performed,and the simulation test and test benchmarking are performed.The research above proves that the designed battery pack thermal model is more reasonable and accurate to reflect the heating characteristics of the power battery pack.It also indirectly verifies the correctness of the constructed single thermal model and lays a foundation for the subsequent vehicle-level thermal management model.The physical model and thermal model of the battery are built by using GT-SUITE software,and the battery model which satisfies the calculation accuracy and calculation speed is constructed by comparing and calibrating with the 3D simulation results.In order to simulate and calculate the power economy of the vehicle,a coupled simulation model of the vehicle driving system and the thermal management system is built,and the model is simulated and tested.The simulation of the working condition and the corresponding test comparison are carried out using the built electric vehicle thermal management system model,and the accuracy of the simulated model is verified.On the basis of this,in order to shorten the high temperature,low temperature fast charge time and increase the driving range under the limit temperature,several optimization schemes are proposed and verified by simulation model. |
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