GM patent: dual charging ports could provide more energy flexibility for electric trucks

General Motors recently filed a patent application for a dual charging port setup to maximize the Ultium battery system in its electric pickup trucks.

GM has developed a dual battery pack, which is already used in the GMC Hummer EV and will be used in the upcoming Chevrolet Silverado EV and GMC Sierra EV. The proposed setup could make the two-tier charging method more flexible.

Using a series of controllers and switches, and the built-in ability of the packs to operate as two different packs in series or parallel, the application illustrates different charging scenarios for a two-tier vehicle.

For reference, in the GMC Hummer EV, 12 battery modules are wired in series to form one layer that is functionally a separate battery pack. That layer is connected in parallel with another identical layer with the same number of modules. In the case of the Hummer EV, the battery capacity is over 100 kwh and is charged at 800 volts to take advantage of the faster 350 kw DC fast charging hardware.

GM outlines that one charging port can be configured to charge at 800 volts or 400 volts, while the other port is connected to the second layer of the pack and is limited to 400 volts. The system could connect them in series and use only the first port to charge both the upper and lower layers simultaneously at 800 volts. Alternatively, they can be connected in parallel to charge both layers at 400 volts.

The third configuration, GM noted, separates the two layers and charges them one at a time. Alternatively, the second port could be used to charge accessories at 400 volts while the vehicle continues charging at 800 volts. This would allow GM trucks to power tools and other equipment while charging. Ford advertises the F-150 Lightning as a mobile power source, but it has only one charging port.

GM also states that a second charging port can be upgraded to 800 volts by adding another switch. The diagram submitted with the patent application depicts both ports side by side. This layout probably makes more sense for fleet vehicles charged in company garages than for personal vehicles, which would likely benefit from having ports on both sides.

It is unclear whether GM will actually put dual charging ports into production, but trucks with dual battery packs are on the rise. The Chevrolet Silverado EV and GMC Sierra EV are both slated to hit the market in 2023 as 2024 models.