The Analysis Of Liquid Cooling And Research On Temperature Control About The Li-Ni-Co-Mn-O Lithium Ion Battert

With the rapid rising of the new energy vehicles,batteries used the main power source.the Li-Ni-Co-Mn-O lithium ion battery has been gradually exploited by the market because of its high energy density and good cycle performance.In this paper,Li-Ni-Co-Mn-O lithium ion battery as the object,with a domestic electric vehicle as the carrier to study the design of the battery pack and its thermal effects.The diversity of temperature about the internal battery is greater difference which will cause serious safety accidents.Thermal management objectives:the temperature difference between the local individual should be controlled at 3-5 degrees,the highest part of the temperature can not exceed 40 degrees to carry out the work.The thermal analysis of the Li-Ni-Co-Mn-O lithium ion battery power pack has the value of analytical research.The advantages of the cathode materials used in the Li-Ni-Co-Mn-O material and the three methods of thermal management are described.This paper chooses cylindrical wind Li-Ni-Co-Mn-O battery.The performance of the battery monomer was tested,the structure and heat source of the battery monomer were analyzed.According to the experimental data,the change of surface temperature under different magnification of the object and the discharge depth under different temperature are analyzed,and the performance characteristics of the battery are analyzed.According to the technical requirements of EV,the inner structure of the battery pack is designed to determine the required capacity and voltage.The arrangement and location of the battery is suitable for the size of the car body.The mechanical structure of the battery pack for electric vehicles is designed,including the sealing method,the selection of sensors,the design of wiring harness,etc.Breakthrough in the design of water cooling plate in the conventional battery pack,making double rotary cooling structure design for the battery pack.Determine the initial heat dissipation mode,clear the heat management process scheme,put forward the heat dissipation design goal.The structure of water cooling pipe with bidirectional inlet and outlet is designed,and the conception of adding heat conducting parts is put forward.Use the graphics software to make mathematical models,with professional CFD software to simulate the fluid thermal effect of battery,improve water pipe design,comparison of the heat dissipation analysis before improvement,finally meet the original design goals,the temperature difference between the battery's control in a reasonable range.Considering the temperature control method to reduce the battery temperature difference,improve the cooling temperature control method.In order to make the temperature control system get faster,the traditional method of battery temperature as the threshold is discarded.After improving the method,the temperature of the coolant is used as the threshold,and the temperature of the coolant is selected to obtain the optimal threshold temperature.The temperature control mode and output parameters under different environment temperature,battery temperature and cooling temperature are proposed through the real vehicle condition data,and the thermal management target is further enhanced from the temperature control method.Two aspects of structural design and temperature control method are studied,and finally,the expected thermal management objectives are achieved through test and simulation verification.