| In the context of energy crisis and environmental pollution,electric vehicles?EVs?have made great strides because of its low fuel consumption and zero emissions.As the core component of EVs,the performance of power batteries restricts the quality of whole vehicles.Since the energy,capacity,and safety of the battery are obviously affected by temperature,designing an efficient battery thermal management system and revealing the heat transfer laws of the system have important practical significance for improving the performance of the battery.This paper focused on the simultaneous optimization of the temperature control effect and energy density of the battery thermal management system,designed a battery thermal management system based on wedged microchannel cold plate.And the method of numerical simulation was used to reveal the heat transfer and temperature control laws of the battery thermal management system.The main conclusions are as follows:?1?For the research on the thermal management performance of microchannel cold plate,this paper effectively characterized the heat generation characteristics of batteries at first.After that,this paper took the heat generation of 1cm thick battery body under1.5C rate as the heat flux boundary,and simulated the temperature control effect of cold plate under different mass flow rates and channel numbers.The results show that as the mass flow rate gradually increased from 2.5×10-5kg/s to 4×10-5kg/s,the maximum temperature of the cold plate surface gradually decreased,the temperature rise rate gradually slowed down and the peak point of the maximum temperature of the plate surface was reduced from 55.09°C to 44.67°C.Besides,increasing the number of channels can further strengthen the cooling effect.However,the microchannel cold plate has a poor temperature uniformity,when the maximum temperature of the plate surface was effectively controlled within 45°C,the maximum temperature difference of the plate surface was still as high as 6.69°C.?2?For the optimization of the thermal management effect of the traditional microchannel structure,this paper first studied the temperature control performance of the traditional structure under different heat flux intensities.Subsequently,battery thermal management systems based on wedged channels and bifurcated channels was designed,and the thermal management characteristics of the cold plate under different channel structures and mass flow rates were studied.The results show that under the3.5C rate heat flux,the surface temperature of the conventional structure plate can reach59.26°C under 2×10-4kg/s flow rate,and the surface temperature difference exceeded15°C.With the application of wedged-formation channels,the outlet aspect ratio of 1:16reduced the surface temperature and temperature difference by about 16.54%and33.12%,respectively.After that,as the flow rate of the cold plate increased,the surface temperature and temperature difference of the plate were gradually controlled below40°C and 5°C.Besides,the synergistic effect of the bifurcated structure and the wedged channel can further strengthen the cooling and temperature uniform effect of the cold plate.?3?For the heat transfer enhancement of battery thermal management system based on wedged microchannel cold plate,this paper considered the anisotropic thermal conductivity of batteries,and compared the temperature control effect of the system under different heat dissipation surfaces,mass flow rates,channel distributions and other conditions.The results show that when the cold plate was heated on one side,compared with front heat dissipation,side heat dissipation reduced the temperature difference of batteries by about 35.71%?1.5 C?,38.33%?2.5 C?and 44.28%?3.5 C?at different discharge rates with the flow rate of 2×10-5kg/s.At 3.5C discharge rate,as the flow rate gradually increased to 1×10-4kg/s,the peak temperature of batteries was reduced from about 60°C to 45°C,and the proposition of the halberd-type channel distribution reduced the peak temperature difference of batteries from 7.27°C to 4.67°C.When the cold plate was heated on both sides,the arrangement of insulated gas seams in the inflow section of the halberd-type channel further strengthened the temperature uniformity of the system under even higher heat loads,a good thermal management effect was verified.This paper has 44 figures,11 tables,105 references. |
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