Lithium Ion Battery Thermal Characteristics Analysis And Management Research Technology

With the increasingly severe environmental pollution and energy shortage,the new energy industry has been developing rapidly,and electric vehicles have become an alternative to traditional fuel vehicles.In the process of technological development of electric vehicles,although the performance of electric vehicles has been greatly improved,the safety and stability are still not completely guaranteed.The explosion accidents of electric vehicles occur from time to time,and the main problem is the management of lithium ion batteries.As the core component of the power system of electric vehicle,ensuring the safety and efficiency of lithium ion battery is the focus of research.In the working condition of the vehicle in the operation of the lithium ion battery for working temperature is more sensitive,cause the lithium battery explosion is ultimately temperature management issues,and in many lithium battery management system of temperature monitoring and control is based on lithium battery as a measure of the external temperature,and temperature on cell surface temperature as control index control strategy has limitations,for temperature control,only by strengthening the cooling means to the way to control the temperature cannot achieve the timely and effective.This paper takes the 18650 lithium ion battery of tianjin lishen co.,LTD as the research object,aiming at the thermal characteristics and management technology of lithium ion battery.The main research contents of this paper are as follows:(1)Starting from the principle of lithium battery,study the thermal generation and heat transfer characteristics of lithium battery,analyze the applicable scenarios of various models of lithium battery,and build the equivalent circuit model of thermal resistance to estimate the internal temperature of lithium battery and lithium ion battery due to the limitations of thermoelectric coupling model in engineering.(2)Starting from the equivalent circuit model of thermal resistance of lithium battery,conduct HPPC performance test experiment on lithium ion battery,and identify the model parameters offline according to the experimental results;The thermal resistance of lithium battery was identified by recursive least square method.By using the adaptive filtering algorithm,the specific derivation algorithm applied to internal estimation is deduced.By building the thermoelectric coupling model of lithium battery on COMSOL platform,the internal temperature estimation of the equivalent circuit model of thermal resistance of lithium battery is simulated and verified to determine its feasibility.(3)In the process of analyzing the thermal characteristics of lithium ion batteries,the optimal operating temperature range of lithium ion batteries is studied according to the influence of temperature rise on the performance of lithium ion batteries,and the main factors of temperature rise of lithium ion batteries are judged according to the temperature rise of lithium ion batteries.On the basis of analysis of thermal characteristics of lithium battery and internal temperature estimation,a temperature control strategy based on multi-parameter fusion is designed to achieve the purpose of controlling lithium battery temperature through internal temperature.A simulation environment is built on ADVISRO platform to conduct UDDS working condition simulation and verify the effectiveness of the control strategy.(4)Build a lithium ion battery management system platform to verify whether the accuracy of collection parameters of the experimental platform meets the requirements.According to the characteristics of the thermal management system,the thermal management strategy based on internal temperature estimation is implemented on the underlying embedded platform,and the numerical stability is guaranteed.