To solve the problem of heating in electric vehicle air-conditioning systems and suppressing the high discharge temperature of the compressor in winter

a quasi-two-stage compression heat pump system for electric vehicles has been designed using flash tank vapor injection. Additionally

an experimental platform for testing the performance of a quasi-two-stage compression scroll compressor has been built. Using this platform

single-stage and quasi-two-stage compression scroll compressors have been tested under five different outdoor temperature conditions. The experimental results show that the discharge temperature of the compressor increases with the decrease of ambient temperature. Under all five conditions

the discharge temperature of the single-stage compression scroll compressor is higher than that of the quasi-two-stage scroll compressor. In particular

when the ambient temperature reaches ﹣7℃

the discharge temperature of the quasi-two-stage compression scroll compressor is 10 ℃

less than that of the single-stage compressor. In low-temperature conditions

compared with the single-stage compression scroll compressor

the mass flow rate of the quasi-two-stage compression scroll compressor

the system heat capacity and heating coefficient of performance (COPh) improve by 12.9%–17.4%

7.3%–8.3% and 7.6%–8.2% respectively.