Study On Thermal Management Of Power Battery Based On Thermoelectric Effect

Thermoelectric cooling technology is a solid-state refrigeration technology with no refrigeration,no noise,cooling and heating.In the case of direct current,thermal electric cooler(TEC),based on thermoelectric cooling technology,can transfer heat to achieve refrigeration.Compared with the traditional way of natural cooling or liquid-cooling,thermoelectric cooling mode is simple,convenient and quick operation,and the temperature on cool side can be adjusted.Therefore,thermoelectric cooling technology provides a new idea for thermal management of power battery.TEC is applied to the thermal management of power battery.First of all,the performance of thermoelectric refrigeration is analyzed.It would be difficult to model a large amount of thermocouple arms in TEC.So this thesis proposes and verifies the compact model of thermoelectric refrigeration tablets by combining simulation with theoretical calculation.And based on this model,the influences of external factors on the performance of the TEC were studied by the numerical analysis,respectively,such as convective heat transfer coefficient on the cold side,convection heat transfer coefficient on the hot side and the electric current.Secondly,through searching relevant literature and industry indexes,maximum refrigerating capacity and energy efficiency value ? were selected as the selection criteria,and TEC1-12710T150 was selected as the core component of thermoelectric refrigeration mode.In order to make thermal management effect evaluation system,the times was used as an indicator of evaluation,at which the maximum temperature reached 50? or the maximum temperature difference reached 5 ?,respectively.In the end,a small power battery module test bed(3 x 5)with foam copper and paraffin composite heat transfer structure was set up,which used simulating cell instead of real battery.The battery module was used as the research object and the thermocouple test section were reasonably designed.By comparing the thermal characteristics of battery module managed by natural cooling,liquid-cooled or thermoelectric cooling mode,it wasconcluded that thermoelectric cooling technology can be used for battery thermal management.The results were given as follows:(1)Convective heat transfer coefficient on the cold side,convection heat transfer coefficient on the hot side and the electric current all influenced the cooling performance of the TEC in different degree.With the increase of convective heat transfer coefficient in the hot side,the refrigerating capacity and cooling efficiency of TEC gradually increased.However,when it reached a certain value,the trend of its influence tend to moderate,and it did not increase continuously.And the influence of the current on the cold end temperature and the refrigerating capacity of TEC existed a "best value".(2)The thermocouple test segment was designed to meet the expectations,and the highest temperature in the module was found in the middle 8 battery,with the lowest temperature appearing on the 11 cell at the edge.When the heating power is 2 W,the highest temperature of battery module,which was managed by natural convection,reached 50 ? after about 2200 s.When the module was managed by liquid cooling or TEC cooling,the highest temperature was reaching a stable state.And the time went through4420 s,1280s,accordingly.What's more,on the steady state,the highest temperature of battery module managed by TEC cooling was only 31.5 ?,far below the 44.5 ?,which obtained by liquid cooling.So TEC cooling has obvious advantages of temperature control.(3)When the heating power is 4 W,it needed 915 s,1115s and 4465 s to up to 50 ?,and the working time of TEC cooling was 3350 s longer than that of liquid cooling,nearly56 minutes;when the heating power is 6W,compared with smaller power,the time that the highest temperature was up to 50 ? were greatly shorten.And they were 520 s,580s and775 s.But TEC cooling still had good advantages of temperature control.(4)When the heating power is 2W,3 kinds of cooling method can effectively control the maximum temperature difference within 5 ?.When the heating power increased(4W/6W),the maximum temperature difference of the battery module managed by natural convection or TEC cooling can be stable and in 4? to 6 ?.However,the maximum temperature difference obtained by liquid cooling is higher than that of natural convection or TEC cooling,and even after the melting of phase change material,it continued to rise.