Research On Finite Element Modeling And Performance Testing Of 18650 Li-ion Battery

The increasingly severe pollution problems and energy crisis have made the research of new energy technology a hot research topic.With the development of lithium ion batteries,it has been widely used in the field of new energy vehicles.However,in recent years,with the widespread use of lithium-ion batteries,accidents caused by the safety of lithium-ion batteries often occur.Therefore,it is very important to study the changes in the mechanical properties of electrode materials caused by the charging and discharging of lithium-ion batteries.Improving the overall performance of lithium-ion batteries has good guiding significance.During the electrochemical cycle,lithium-ion batteries will have different stress states due to different operating conditions,showing different characteristics,which seriously affects the safety of battery use.In order to effectively monitor and use lithium-ion batteries,it is necessary to study the charge-discharge behavior of lithium-ion batteries under different operating conditions,and to characterize the relevant mechanical behavior of the main materials of lithium-ion batteries.Support of the finite element model.Based on the current research status of power lithium-ion batteries,this paper systematically analyzes the above issues,as follows:(1)The capacity characteristics of lithium-ion batteries under multiple charge and discharge cycles at different rates were studied.The charge and discharge rates of 0.5C,1C,2C,and 3C were used to test multiple cycles of 18650 lithium batteries in the same batch,and the battery capacity,current,and voltage were comprehensively monitored.It was found that at large rates and multiple cycles,Under the conditions,the capacity will be accelerated.(2)The uniaxial tensile test method was used to study the tensile strength and tensile modulus of positive and negative electrode materials before and after multiple cycles at charge and discharge rates of 0.5C,2C,and 3C.The results show that the tensile strength and tensile modulus of the positive and negative electrode materials decrease with the increase of the cycle ratio and the number of cycles,and the change in the tensile properties of the positive electrode material with the cycle ratio and the number of cycles is similar to that of the anode material the same.(3)Using the in-plane compression test method,the compressive strength and compressive modulus of the positive and negative electrode materials before and after multiple cycles at charge and discharge rates of 0.5C,2C,and 3C were studied.The results show that the compressive modulus of the positive and negative materials decreases with the increase of the ring rate and the number of cycles,and the compressive strength of the negative material increases with the increase of the cycle rate and the number of cycles.difference.(4)The mechanical behavior characteristics of the positive and negative materials under tension and compression were simulated.The finite element model of ANSYS was compared with the experimental data to verify the rationality of the model.