4. Fast DC charging


  • Unlike AC charging, the charger is not located in the vehicle during DC charging.
  • The conversion of the ac voltage and current into the dc quantities is ensured by an external charging station.
  • The DC voltage of the charging station is directly connected to the traction battery terminals.
  • The BMS is communicates with the charging station and sets the voltage level.



  • The external installation of the charging station enables to design the charger for significantly higher power rates.
  • Outputs of tens to hundreds of kW (power of 150 kW is wide spread, actual maximum power up to 350 kW)
  • The charging time is significantly shortened (about tens of minutes to just several minutes).
  • However, fast charging also has disadvantages, in particular
    • large charging losses yielding costs,
    • shortening battery life (loss of capacity),
    • higher price per kWh.




  • The actual condition of the battery when arriving to the charging station greatly affects the charging speed.
  • Actual charging speed mainly depends on
    • temperature,
    • cell disbalancing.
  • Based on these parameters, battery management determines the charging speed.
  • Charging speed is slower when intensive cell balancing is needed. 
  • In addition to the temperature, the charging speed is therefore determined by the driving style.
  • Nonaggressive drivine at favorable temperatures → fast charging.
  • Aggressive driving (accelerations and braking), unfavorable temperatures → charging power does not reach the power rate of the charging station.




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