Megawatt Charging System for Electric Vehicles
J3271
This document describes the megawatt-level DC charging system requirements for couplers/inlets, cables, cooling, communication and interoperability. The intended application is for commercial vehicles with larger battery packs requiring higher charging rates for moderate dwell time. A simplified analog safety signaling approach is used for connection-detection to guarantee de-energized state for unmated couplers with superimposed high speed data for EVSE-EV charging control and other value added services.
Rationale: DC charging of heavy duty (HD) commercial trucks at ~megawatt power levels (up to 1500v/3000A) requires a dedicated charging ‘system’ specification that covers couplers, cables, cooling, communication and interoperability. Commercial applications have much higher reliability expectations, proposed as >99.99% success rates for startup on the first attempt, with uninterrupted completion. Improving charging session reliability while maintaining existing number of contacts/conductors can be achieved by superimposing communication (differential PLC, CAN) signals over “connection-detection” analog signals. Mapping of ISO 15118 XML signals to CAN is already standardized in SAE J1939-DA, for local charging control and scheduling. The EtherNet tunnel is only used on plug-and-charge and other applications with encryption needs.
