Discharge Characteristics Of Power Battery And The Effect Of The Installation Of Power Battery On Dynamic Characteristics Of Electric Vehicle

Li-ion battery has become the dominant power for electric vehicles because of its high specific capacity and power. However, its discharge performance, thermal stability, safety and limit endurance mileage which are greatly influenced by the work environment restrict the development and its application in electric vehicles. The Li-ion battery as an energy supply system of new energy vehicles, some characteristics are same as energetic materials. So took cook-off method which was used to research energetic materials thermal stability to test Li-ion battery. Series working environment were simulated by test-box and discharge current controller, carried out experiments about discharge of LiFePO4Li-ion battery, and the performance of Li-ion battery operating voltage, discharge time, capacity, temperature rise of the battery pack were analyzed. Gain laws of discharge performance, thermal stability and safety which change with discharge current, temperature, humidity and the ratio of volume and areas.The thermal mathematical model of the Li-ion battery was established based on electrochemical and heat transfer theory to estimate the battery heat generation rate during discharge process. The numerical model of the li-ion battery was built by ANSYS to simulate temperature distribution and thermal effects of series working condition, to understand differences of thermal characteristics between single cell and battery pack under different operating conditions.Besides, the finite element model was built by HyperMesh to research conversion design scheme, and freedom modals of the frame was analyzed by Radioss to judge design scheme whether suitable or not. So designers can recognize the influence of battery pack installation location on vehicle frame modal characteristics.In this article, experiment and simulation were combined to developed series research for battery work characteristics and battery pack installation designing. The cook-off research method provides an experimental measurement for evaluation of Li-ion battery thermal stability. Data provide guidance for thermal management system and environment air condition design of electric vehicle. The frame modal analysis can guide the designing for battery pack installation.