| In the dual pressure of the energy consumption and environmental problems, the development of a EV/HEV based new energy vehicle is by the world’s high voice. As one of the core technology of restricting the performance, the battery thermal management system has always been a hot topic and focus of the study of the industry. The rational thermal management system can control the power battery in optimal working temperature range to improve the battery cycle life, which has a great effect on the improvement of vehicle performance. This paper employed the composite phase change material/liquid cooling pipe as heat transfer channel for battery thermal management system of lithium ion power battery. Studying on the preparation of the phase change material and its calculation, designed a phase change rod with high heat conduction that can match with 32650 cylindrical cell according to the battery heat generation mechanism and heat transfer theory. And then developed a set of injection model for forming the rod rod/cooling channel, set up the rod/cooling channel experimental platform for the battery thermal management through the three-dimensional calculation and structure analysis the phase change rod with high heat conduction. Studying on this system performance through the experiments of different charge and discharge rate with natural convection and forced convection at room temperature and under high temperature. The main research contents and conclusions are as follows:1、Research on lithium ion power battery internal heat production mechanism and he effect of temperature on the charge discharge performance and life; Research on the thermal property calculation of lithium ion battery and the cooling effect of cooling/liquid phase change; The design of experimental system for the PCM module are used for cooling the 48V10.5Ah battery pack under low magnification (1C) discharge at constant environment temperature are 40oC,43oC,46oC,and verified that the PCM system can improve the cooling capacity and uniforming temperature capability.2、Tensile and bending performance experiment was carried out of the high thermal conductive plastic N720, respectively according to the standard GB/T 1040 "plastic-tensile properties test" and GB/T 9341-2000 the plastic-bending performance test, including the standard injection molding process before the test; On the premise of feasibility of thermal simulation, according to thermodynamics and structure and mechanical properties of high thermal conductive plastic, a used to fill in central composite PCM materials and used to connect the thermal conductivity of liquid pipeline rod was designed.3、The single parting surface injection mold was designed, and through continuous modification, finally a high thermal conductive rod injection mold that is used to the 32650 battery module was developed; On the basis of fluid mechanics, serpentine coil structure was designed, and with a 3.5 mm plastic tube go through the high thermal conductivity rod, and double pump structure (10 W and 4.5 W) were used, which can fully guarantee the tube flow taking away the quantity of heat of PCM.4、Charge and discharge experiments of battery module by 1c/2c/3c with natural cooling were carried out, and temperature change was analyzed during the work aside time, and make a comparison between the seal and the unseal condition; Charge and discharge experiments of battery module by 1c/2c/3c with forced cooling were carried out, and reasonable air duct structure was designed, and a fan of the power of 12W was used to balance the cooling of the battery, the result was compared to the last; Constant temperature of 40 ℃ experiment was carried out with a high temperature box, then compared the data of natural cooling with the data of rod cooling, and the results show that TDisMax=55.5 ℃ and TChaMax=52.3 ℃ when charged and discharged by 2C, which was reduced by 9.2% and 6% compared with high temperature box natural cooling respectively and show that TDisMax= 46.2 ℃ and TChaMax=45.8 ℃ when charged and discharged by 1C, which was reduced by 8% and 7.9% compared with high temperature box natural cooling respectively. And the local temperature difference was controlled within 2 ℃; With the liquid cooling scheme,there was no obvious change by 1 c discharge, but when 2C high rate discharged, highest temperature of liquid-cooled experiment was 3 ℃ lower than the rod cooling, playing a better role in the performance optimization. |
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