Thermal Simulation of CCS Charging Inlet at High Charging Currents with various Optimisation Approaches

Current status: In Europe, the CCS charging standard for electric vehicles is the most widely used charging system. In order to reduce the inconveniences caused by long charging times, the CCS charging standard has been gradually adapted to the need for higher charging capacities. Currently, charging currents of up to 500A are supported at a charging power of up to 500kW. In order to decarbonise road transport, commercial vehicles are also increasingly being electrified. Problem definition: Battery-electric commercial vehicles in particular have large battery capacities with several hundred kilowatt hours, some of which do not have enough energy for an entire working day, which is why they need to be recharged if necessary. High charging power with correspondingly high charging currents is required to recharge the electrical energy storage units of commercial vehicles in an acceptable time. Due to the electrical losses, waste heat is generated, which places a thermal load on the charging components. In particular, the CCS charging socket is subject to high thermal loads and, for safety reasons, must not exceed the maximum temperature of 90°C in accordance with standard DIN EN IEC 62196-1. Depending on the ambient temperature, the charging socket in the charging path often represents a thermally limiting component, as the charging current must be reduced before the maximum temperature is reached. Solution: Three general solution approaches are used to investigate how the CCS charging socket can be improved for the thermal challenge. The three general solution approaches are: • Reduction of heat generation • Transmission of unavoidable heat • Removal of heat from the overall system Objective: The current CCS charging socket is represented by a detailed, specially designed Matlab thermal simulation model. A specific optimisation approach is derived for each of the three general solution approaches. The aim is for the optimisation approaches to result in the smallest possible component changes. The thermal simulation shows the effects of the optimisation approaches compared to the initial state. Target realisation: The general solution approach: Reduction of heat generation, is investigated by the optimisation approach: Increase of plug contact force. The general solution approach: Transmission of unavoidable heat, is investigated by the optimisation approach: Increase of thermal mass. The general solution approach: Removal of heat from the overall system, is investigated by the optimisation approach: Change of the insulator material. Finally, the temperature behaviour of the CCS charging socket in the initial state is compared with the simulation result, in which all individual optimisation approaches are implemented together.