Three-dimensional temperature field analysis of the lithium ion battery

Source: 2020 - 04 - 12 21:33 hits: 3 d temperature field analysis of lithium ion battery ( 1) Because the internal battery electrolyte liquidity is poor, you can ignore battery internal convective heat transfer; ( 2) Inside the battery will have little impact on the heat dissipation, radiation can be neglected; ( 3) Battery internal various material is isotropic, so the temperature inside the battery only along the radial direction of change, in the other direction remains the same; ( 4) Heat evenly to produce in the battery. In the four hypothesis, because there are heat on both ends of the battery, so get rid of the third hypothesis, which can establish a cylindrical lithium-ion battery, a three-dimensional transient heat transfer mathematical model: ( 1) Type t to battery temperature, ℃; As the cell density, kg/m3; J/(specific heat C for battery, kg℃) ; Time s; L to sink heat conduction system, W/( m℃) ; R is the radius of the battery, m; For the battery rounded corners, rad; Z is the length of the battery, m; Q for the battery unit volume heat production rate, W/m3. 2. Lithium ion batteries, the three-dimensional finite element model was established, the axis of a cylindrical lithium ion battery is around the middle plane of symmetry, so the finite element model of lithium ion batteries should be based on half shaft upwards. Due to the lithium ion battery on the radial is axisymmetric, so it can be a quarter of the lithium ion battery finite element model is established on the radial. Cylindrical lithium-ion battery three-dimensional finite element model is set up as shown in figure 1. 3. Generate internal heat measurement to determine the formation and internal method basically has two kinds: one is directly measured by experiment; ( 2) Type of Q for the battery unit volume heat production rate, W/m3; I is the battery discharge current, A; V is for battery capacity, m3; T for the battery temperature, ℃; Eoc for battery open circuit voltage, V. E work for battery voltage, V. 转换端- E =IR( R for battery internal resistance) , its range is very small, its value is - 0. 5 mV/K。 Thus, we can calculate the icr65/400 lithium ion battery in the heat production rate of 1 c discharge as shown in table 1. 4. Results analysis of icr 65/400 lithium ion battery performance parameters are shown in table 2. Assuming that the battery to discharge under the temperature of 300 k to start around the temperature of the fluid is 300 k. Respectively using data ICR65/400 type lithium ion battery temperature field analysis of the 2 d and 3 d analysis, and analyzed and compared, and the final results of the analysis of different convection heat transfer coefficient, the influence of battery temperature field in this article, first of all, on the basis of two-dimensional analysis, finite element analysis software ANSYS ICR65/400 for lithium ion batteries to analyze three dimensional temperature field, through the analysis and comparison of 3 d than 2 d analysis more accurate. Analyzed the different convection heat transfer coefficient for the influence of the temperature field of battery. The results show that with the increase of convective heat transfer coefficient, the highest temperature of battery is smaller, the influence of heat transfer coefficient is bigger, the better. 5 conclusion on the basis of two-dimensional analysis, using ANSYS software to icr65/400 lithium ion battery temperature field is analyzed. Through analysis and comparison, the 3 d than 2 d analysis more accurate. Analyzed the different convection heat transfer coefficient for the influence of the temperature field of battery. The results show that with the increase of convective heat transfer coefficient, the highest temperature of battery is smaller, the influence of heat transfer coefficient is bigger, the better.