| In recent years,the development of electrochemical energy storage has been extremely rapid.With the development of technology and the reduction of cost,the application scale of lithium-ion batteries is increasing large,and the prospect is widely optimistic.However,the electrochemical performance and cycle life of the battery are significantly affected by the temperature,and either too high or too low temperature will adversely affect the performance of the battery.Therefore,a reasonable battery thermal management system is of great significance for the safe operation of energy storage systems.In this paper,the air-cooled heat dissipation of single cells and battery packs is investigated,as well as the energy consumption of air conditioning system operation is analyzed.The main research contents of this paper are as follows:(1)The structure and working principle of lithium-ion batteries are summarized,the charging and discharging experiments of single battery with different rates are conducted,and the thermal model of lithium-ion battery is established and compared with the experimental data.The results show that the maximum error between the simulated value and the experimental value is within 2℃,which verifies the reliability of the model.The battery pack was modeled and simulated,the heat dissipation demand of the battery pack was studied by changing the inlet temperature and inlet flow rate,and the minimum flow required of the battery pack at different rates charge/discharge cycle and different inlet temperatures was obtained.The results show that natural convection can meet the heat dissipation demand of the battery pack during 0.5C charge/discharge cycle;during 1C charge/discharge cycle,even if the inlet temperature is as low as 20℃,forced air cooling is required to meet the heat dissipation demand,and the critical inlet flow rate is 0.02m~3/s at this time.(2)The energy efficiency of the battery at different rates and the thermal resistance of the insulation material are analyzed,and then the changes of the energy consumption of the air conditioning system and the container room temperature are studied according to the compressor model and the container temperature mathematical model established earlier.The results show that as the charge/discharge rates increases,the energy efficiency of the battery decreases;as the charge/discharge rates increases,the opening time of the air conditioning system in the container increases,leading to an increase in the energy consumption of the air conditioning system.The compressor is the main energy consuming equipment,at 0.5C and 1C rates charging and discharging,the compressor turns on for139.95 hours and 2551.25 hours,and the energy consumption of the compressor is 285.66k Wh and 3653.78 k Wh.In actual condition,the opening time and energy consumption of the air conditioning are the smallest,38.405 hours and 71.49 k Wh respectively.At 0.5C and1C rates charging and discharging,the energy consumption of air conditioning in intermittent operation mode is reduced by 4319.38k Wh and 2437.65k Wh than that in always-on operation mode,respectively. |
