Liquid-cooled charger cable maker Huber+Suhner says a short-circuit in an older prototype CCS connector plug is the cause of a world-wide shutdown of 150+ kW electric vehicle charging sites.
The shutdown has disabled CCS charging at the large majority of Electrify America’s highway charging locations in the United States and has disabled some chargers that are part of the Ionity and Fastned networks in Europe. Scattered shutdowns have occurred at other sites and charging providers as well.
According to a new press release, “at a charging station on a test site of a customer in Germany, a short-circuit occurred with a HUBER+SUHNER cooled high-power charging cable. Nobody was injured in this incident. The short-circuit occurred in the plug. The cooling circuit with the synthetic, non-conductive coolant can be ruled out as the cause. The product in question is a first-generation prototype.“
The statement says that the prototype cable was first made in 2017 and that the final production cables “differ from the first prototypes by, among other things, increased sealing.“
According to company spokesperson Alex Rienitz, “increased sealing” does not refer to leakage of the non-conductive coolant fluid. Instead, it refers to ordinary water in the form of humidity (or perhaps condensation) getting into the connector plug.
The coolant fluid used is “a mixture of synthetic esters and additives. It has a high dielectric strength and can therefore not cause any short-circuiting. The term ‘increased sealing’ relates to outside humidity that could potentially diffuse into the connector”, he said.
Condensed water or surface moisture could occur if the plug is colder than the surrounding air. Rain or fog might cause similar problems on conventional connector plugs with inadequate sealing.
Pure water is not necessarily a good electrical conductor but this changes if it mixes with even small quantities of salts, dust, or other contaminates.
This information is consistent with previous reports that the incident involved a prototype cable and connector that differs in design from the final product that is installed at public charging locations.