Study On Heat Dissipation Of Simulation 18650 Lithium-ion Battery Module Based On Thermoelectric Refrigeration Technology

With the increasingly strong demand for environmental protection,human development needs to consider more environmental factors,live in harmony with nature,and achieve sustainable development.The exhaust emissions from fuel vehicles cause great pollution to the environment.With the joint efforts of governments all over the world,new energy vehicles have gradually been put into the strategic position of human development,and power batteries are the main power source of new energy vehicles.Its working performance,safety and service life are closely related to temperature,so it is particularly important for new energy vehicles to maintain the power battery in a suitable temperature range.Thermoelectric refrigeration has been used in more and more fields because of its advantages of no pollution,no noise,integrating refrigeration and heating,and so on.In recent years,there are more and more researches on the application of thermoelectric refrigeration technology in the field of battery thermal management.With the continuous improvement of the performance of thermoelectric materials,thermoelectric refrigeration technology will be paid more and more attention in this field.In this paper,the thermal principle of lithium battery and several common thermal management methods of power battery are introduced,and then a set of thermal management system of power battery based on thermoelectric refrigeration is designed and fabricated.The theoretical and experimental analysis is carried out from the selection of thermoelectric cooler(TEC),the selection of thermal management mothod,the arrangement position and quantity of thermoelectric cooler on the effect of battery thermal management,which will be carried out from the following aspects:(1)Through the performance analysis of three kinds of thermoelectric cooler(TEC1-12704,TEC1-12705,TEC1-12706),the most suitable type is TEC1-12706.(2)According to the shape and heating characteristics of 18650 lithium-ion battery,the insulated heating rod is used to design the simulation battery module,and then the battery thermal management experimental platform is built according to the experimental requirements.(3)The driving state of the new energy vehicle is divided into three states: uniform driving,low speed acceleration and high speed acceleration,and the three states correspond to different battery heating power.The battery heating power is 2W at uniform speed,3.3W at low speed and 5W at high speed.In the case of low speed acceleration and high speed acceleration,the temperature rise rate of battery in battery module under natural convection heat dissipation,liquid cooling heat dissipation and semiconductor refrigeration are compared respectively,it is verified that the semiconductor refrigeration is obviously superior to the other two ways.(4)The thermal management experiments of battery are carried out by using semiconductor refrigeration heat dissipation method under three driving conditions,and the influence of the position of thermoelectric cooler on the heat dissipation effect is discussed.When a semiconductor refrigerator is placed in the side center of the battery shell,the temperature of each battery does not exceed 50? in the studied time,but the maximum temperature difference between the batteries exceed 5?,which does not meet the requirements.When a thermoelectric cooler is placed in the bottom center of the shell,the maximum temperature difference between the battery monomers under three driving conditions is less than 5?,and the temperature of each battery does not exceed 50?.However,the temperature of the battery rises faster than that of a thermoelectric cooler placed in the center of the side.In order to make up for this disadvantage,two thermoelectric coolers are arranged on the bottom surface of the battery shell to carry out the battery thermal management experiment.The experiment result shows that the temperature rising rate of each battery slows down,but the temperature uniformity decreases slightly,which is related to the gap between two thermoelectric coolers,because the gap is exactly the worst heat dissipation condition of the battery module.However,under the three driving conditions,the maximum temperature difference between the batteries does not exceed 5?,which meets the requirements.