Future Stellantis EVs might flex 800V at 400V Superchargers

• Patent enables higher charge rates from lower-voltage DC fast chargers
• Solution adds a series of relay switches and a capacitor
• It’s a smart workaround for Tesla V3 Superchargers, which can’t charge at 800 volts

Stellantis is working on hardware to boost the output of low-power DC fast-chargers for electric vehicles that can handle that extra power, while keeping added weight and complexity to a minimum.

Between the lines, although the patent makes no mention of Tesla, it could make a serious real-world charging difference. The idea might allow 800-volt EVs—large EVs like the upcoming Ram 1500 REV—to charge at a higher rate when plugged into sub-800-volt fast-charge connectors, such as the vast majority of those on the Tesla Supercharger network.

Stellantis confirmed plans to adopt the Tesla-based charge port, otherwise called NACS and now part of a standard called SAE J3400, in February.

This proposed boost system is described by the automaker in a patent filing published by the United States Patent and Trademark Office (USPTO) Oct. 31, 2024, but originally filed Apr. 25, 2023. In it, Stellantis says the system is designed to take full advantage of the charging capabilities of 800-volt vehicle electrical architectures even when charging at 400-volt DC fast-charging stations.

While dedicated DC boost modules exist, these add significant cost and weight, and can be difficult to package, Stellantis says in the document. As an alternative, the automaker proposes using a series of relay switches to boost voltage. These switches, along with a small DC capacitor, would be the only additional components needed, according to Stellantis, which added that such hardware could be applied to plug-in hybrids as well as EVs.

When charging at a lower-power station, the relay switches would allow current to flow through a vehicle’s inverter and an electric motor during charging, with those components generating two AC phase currents that could be converted into a third, higher-power DC current that would then be fed into the battery.

The feature might not immediately be relevant for all that many models. Stellantis is sticking with a 400-volt architecture for most of the near-term EVs built on its STLA platform strategy set to underpin the 2024 Dodge Charger Daytona and 2024 Jeep Wagoneer S. But it has confirmed those big Ram EVs will charge at 800 volts.

Streamlining charging hardware has been a major focus for Stellantis. In 2023 the automaker discussed plans to drop onboard chargers and inverters altogether in a bid to simplify future EVs.