Traction battery cooling system for Škoda 18T Eskisehir and 28T2 Konya trams

ABOUT THE PROJECT: Customer: Škoda Electric, a.s., Year of implementation: 2014 – 2018, Number of vehicles: 16 + 14, Place of operation: Turkey, Eskisehir and Konya

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The system is designed for Škoda 18T Eskisehir and 28T Konya trams for cooling traction batteries during charging and discharging. The batteries are cooled by removing heat from the bottom surface of the traction batteries. The device is mounted in a container supplied by the customer and connected to the cooling lines and traction battery coolers.

The cooling principle consists in removal of the waste heat generated in the traction battery by antifreeze mixture (coolant). The necessary technology to maintain the temperature and the required amount of coolant is built in one section of the traction battery container. The power supply of the cooling equipment is from the 750V traction voltage intermediate circuit, the control supply voltage is from the 24V vehicle network.  For diagnostic purposes, the system is equipped with an Ethernet interface, for connection to the control system with a CAN line.

Two methods are used to maintain the temperature of the coolant of traction batteries; the choice of method used depends on the outdoor temperature. At low outdoor temperatures, the coolant is cooled directly by the outside air in a combined heat exchanger. The coolant temperature is controlled by the amount of outside air passing through thanks to the continuous fan speed control. In other cases, the coolant temperature is maintained by controlling the heat transfer in the R134a refrigerant / coolant exchanger. The control of the transmitted power is provided by the operation of the compressor and the operation of the condenser fans.


  • Control via vehicle CAN network or Ethernet
  • Compatible with TST (Tuning and Service Tool)
  • Advanced diagnostics, event logger and operational data recorder
  • Coolant temperature control system according to external conditions
  • Integrated frequency converters
  • Power supply from overhead line


Technical parameters

Rated cooling capacity

2.5 kW

Rated power supply voltage

750 V DC

Operating range of the supply voltage

500 V – 1000 V DC

Rated control voltage

24V DC

Antifreeze mixture temperature

6°C ± 1°C

Refrigerant in the compressor circuit


Weight of cooling circuit components

190 kg

Communication interface

CAN, Ethernet



POLL, s.r.o.

Výpadová 1676/4a
Praha 16
153 00

IČO: 62967754