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The daisy-chain system would work because of how GM has configured batteries in upcoming models including the Hummer EV, Chevy Silverado EV, and GMC Sierra EV.

Electric vehicles have the capability to offer features that simple gasoline-powered cars and trucks simply can't. From more flexible interior layout design possibilities to regenerative brakes that turn slowing down into electrical energy, we're still learning what the EVs of the future will be capable of. General Motors is experimenting with battery technologies, announcing a feature that allows its Ultium packs to recapture waste heat from the normal vehicle operation and use it to extend range. But this isn’t the only interesting new way a GM EV might work differently than competitors’ models thanks to a patent that shows the possibility for two charge ports and the ability to charge two vehicles off of one DC fast charger.

GM's Ultium batteries use a modular design and can contain between six and 24 modules, depending on vehicle size and performance requirements. Ultium's neat trick is that it can switch the layers of its packs to be connected in either series or parallel. The EVs GM sells today have separated layers of battery modules. The Edition 1 GMC Hummer EV, for example, has a 212.7-kWh pack that offers a range of 329 miles. Green Car Reports, which first spotted the patent, notes that the GMC Hummer EV uses 24 modules, but they are arranged in two sets of 12 modules. A new patent application filed by GM uses the two ports to do a number of interesting things, such as charge multiple EVs in a daisy chain set-up. This kind of battery has been confirmed for the Hummer EV as well as the upcoming Chevy Silverado EV and GMC Sierra EV models, and we suspect we’ll see it in many more GM EVs down the road.

The main idea of GM’s patent is to explore the flexibility allowed by having the switchable connection. The production vehicles operate at 400 volts, with the battery layers connected in parallel. But they switch to series so that they can charge at an 800-volt DC fast charger, such as those from Electrify America. The patent suggests additional possibilities, where an 800-volt charging station could instead charge two EVs connected together via a second charge port, both of which would stay in their 400-volt parallel configuration. That’s clever, and would effectively doubling the number of cars a single DC fast charger can charge up at once, which may become a better and better idea as more EVs are on the roads and start to overwhelm the charging infrastructure. Also, GM has already announced that the Hummer EV will offer bi-directional charging through an optional Power Station, so tools and other electrical devices will work just fine when the truck is parked at a job site or campground. As always, just because a patent application has been filed does not mean this technology will come to market.