Thermal Simulation On Dynamic Lithium-ion Battery During Charge And Its Fuzzy Grey Relational Analysis

A new age of environment protection and energy conservation for auto industrywas hewed out by the technology that using lithium-ion battery in dynamic field.However, the widely use of the lithium-ion battery for automobiles are restrained byits thermal-stability and safty problems. To improve the safty and thermal-stability oflithium-ion battery, the research of the thermal behavior of lithium-ion battery isfundamental and crucial.Therefore, supported by the key basic theory project of the central universitybasic scientific research foundation[531107040300], the electrical behavior, chemicalbehavior and thermal behavior of the lithum-ion battery during charge was analysed inthis paper. The primary works and innovation of this thesis are as follow:(1) The finite difference method was used to compute and analyse the distribution of thepotential and current density on the electrodes of the dynamic lithium-ion battery; anelectric-thermal two-dimensional model was established, the heat-productioncharacters in different temperatures during charging were analysed by using MATLABsoftware, the relationship among charging time, temperature, current and four types ofheat sources including ohmic heat, activation polarization heat, electrochemicalreaction heat and subsidiary reaction heat were studied.(2) An electro-chemical-thermal three-dimensional model was established, thetemperature fields of the dynamic lithum-ion battery in different working conditionsduring charge were simulated by using FLUENT software, and the influence ofthermal factors including current, ambient temperature, convection coefficient andemissivity for the temperature field inside the battery were analysed.(3)A new Fuzzy Grey Relational Analysis method was created by combining theadvantages of fuzzy clustering and grey relational analysis. Based on the simulationresults, comparative analysis between each thermal factor was done by using the newFuzzy Grey Relational Analysis method and the primary impacting factors and thesecondary impacting factors were sequenced so as to provide a theoretical basis foroptimizing the thermal behaviors of the dynamic lithium-ion battery.