Investigation Of The Thermal Control Of Lithium Power Battery With Micro Heat Pipe Heat Sink

The renewable energy industry is booming due to its many advantages,especially such as the electric vehicle industry which is favored by the public.However,one of the important factors that limits the development of power vehicles is the safety of lithium batteries.Due to internal short circuit,acupuncture and impact,a fire and explosion breaks out in the power vehicles.When the battery is short-circuited,a lot of current flows through the battery,which leads to heat accumulation and temperature rise.With the temperature rising,the temperature rise of the power battery pack increases and the reaction inside the battery is violent,which leads to the thermal runaway of the battery.When the temperature of the power battery is continuously increasing and the temperature distribution of the battery pack is uneven,the phenomena such as power decrease,energy decrease and the cycle life decrease will occur,further affecting the security and the service life cycle of the battery and the entire power vehicle.Therefore,it is necessary to explore a heatsink which can slow down or avoid the thermal runaway of the battery.In this paper,a heatsink with flat micro-heat pipe welded aluminum fin coupled with forced air cooling is presented as research object.The heating aluminum plate is used as the heat source(to simulate the heating condition of a vehicle lithium-ion battery),and the heat dissipation performance of the heatsink is tested.The heatsink has the advantages of simple structure,light weight,high heat conductivity,long-distance heat conduction,high temperature uniformity and reliability,and it can be widely used in lithium battery heat management system.Furthermore,the heat dissipation capacity of the heatsink is evaluated by exploring the influence of the heatsink placement Angle,different wind speed and heat pipe heatsink(or no heat pipe heatsink)on the heat source temperature.The numerical simulation is carried out by ICEPAK software to verify the experimental results and enhance the heat dissipation,and optimize the heatsink.The results show that the heat transfer performance of the horizontal heatsink is better than that of the vertical one in natural heat dissipation.In forced heat dissipation,the heat source temperature with the heat pipe heatsink is obviously lower than that without the heat pipe heatsink at the steady state,which is about 50°C;it takes longer for the heat source without heat pipe heatsink to reach steady state than the heat source with heat pipe heatsink,which is about 5 hours.Besides,for heat pipe heatsink,the heat source temperature and the time required for the heat source to reach steady state decrease with the increase of wind speed;under different wind speeds,the total thermal resistance of the heatsink decreases first and then increases with the increase of heating power;at each different wind speeds,the total thermal resistance of the heatsink decreases in turn;under the condition of fixed wind speed and heating power,the thermal resistance of a single heat pipe is slightly different,which may be caused by the experimental error and gravity.By theoretical calculation and analysis,the theoretical simulation values are in good agreement with the experimental measurements.When the convective wind speed is selected as 30 m/s,the heat source temperature distribution can be reduced to about 77°C,and the number of heat pipes is increased to 7,the heat source temperature is more uniform to delay or avoid the occurrence of thermal runaway.