The Power Battery Pack Structure Reliability Analysis And Improvement Of Vehicle

Power battery is the energy source of electric vehicles,and its structural safety is very important for electric vehicles.In order to ensure the safety and reliability of the overall structure of the power battery pack,relevant safety and reliability analysis and testing of the important components of the power battery are required.At the same time,the structural strength of the power battery will also cause failure when subjected to random vibration and shock loads.Once the internal structural parts fails,it may directly affect the performance of the vehicle and the safety of the driver.Therefore,this thesis focuses on the structural design and optimization of the power battery structural parts from the perspective of safety and reliability.This thesis base on the development of a certain pure electric vehicle power battery project as the background to design the structure of the power battery.The whole research process of the thesis is based on numerical simulation and combined with experimental testing as a supplement to carry out the design of power battery structural parts.First,arrange the overall scheme of the power battery according to the needs of the entire vehicle,and select and design the component scheme,and then,conduct related tests and optimizations on the key components of the power battery.Finally,the modal analysis of the power battery and the simulation analysis of acceleration shock and vibration fatigue under the operating conditions of the vehicle are carried out.Under the premise of ensuring the safety and reliability of the power battery structure,the structural design of the power battery components is completed.The main research works of the thesis are as follows:(1)Complete the arrangement of the module structure scheme according to the needs of the vehicle end.Two types of modules are used in a double-layer arrangement,of which there are 7 1P5S(1 and 5 series)modules and 10 1P6S(1 and 6 series)modules.The two modules are connected in series.At the same time,in accordance with vehicle performance and outsourcing requirements,program selection and structural design of power battery structural parts are carried out.(2)Test and optimize the key components of the power battery,including:module structure inflation test,power battery upper cover air tightness test,module output level copper bar coating optimization,and output level copper aluminum bar welding reliability analysis test.Through the above test and analysis,the safety and reliability of the key components of the power battery pack are ensured.(3)Analyze the modal state of the power battery to obtain its first four-order frequency and mode shape to ensure that the first-order natural frequency of the power battery is greater than the natural frequency of the vehicle to avoid resonance with the vehicle.Then,according to the national standard GB/ T31467.3,the impact simulation and random vibration fatigue simulation of the power battery are carried out.On this basis,the structure of the end plate and side plate of the module is optimized to ensure that all structural parts of the power battery are safe and reliable.Finally,carry out the vibration and shock test of the power battery pack to verify that the overall structure design meets the requirements of the national standard.