The current arrangement of one EV per charger creates a limiting factor to practical charging when more electric vehicles are present than chargers, creating potential scheduling issues and bottlenecks. In response to this problem, GM has filed a patent for a tandem charging system.
GM applied to the United States Patent and Trademark Office (USPTO) for it tandem charging patent on April 26th, 2023. The application, which was published on October 31st, 2024, is identified by patent number US 2024/0359575 A1. Seven inventors are listed, all U.S.-based, including Mohammad A. Naiel, Abdulrahman Al-Shanoon, Michael D. Alarcon, Yun Qian Miao, James C. Gibbs, Aniket P. Kothari, and Brian A. Welchko, of Michigan or California.
The GM tandem charging system includes charging cables and other equipment enabling two EVs or multiple EVs to be hooked up to a single charging station simultaneously. The electric vehicles can be linked together to charge in a series or in parallel. A switch controller or other bypass or relay will cause some of the power to be transmitted further down the chain to subsequent EVs.
The tandem system would enable charging multiple electric vehicles at the same rate from a single power source, typically an EV charger. However, the patent indicates the system could also be used without a charger present. In this case, a source EV could be connected to two or more additional EVs and transmit power from its battery to the other electric vehicles.
The tandem charging system GM is patenting would likely be used more for home charging than for public charging stations. If a family has several EVs in the driveway but only a single charger, the tandem charging setup could charge all of the family electric vehicles simultaneously, ensuring all drivers in the family have their vehicle charged and ready to drive at the same time without scheduling problems to solve.
The patent also includes several potential methods for splitting up billing based on relayed electrical power if the different EV users have different accounts. These include capturing an image of the secondary EV’s license plate to associate the cost of charging with the specific owner in public charging areas.
GM’s tandem charging would also allow EVs to remain parked at the station after completing the desired level of charging, removing the need to move the vehicle and drive another up to the charger after each completes charging. This has obvious convenience utility for multiple electric vehicles at a single home charger as well.
Comments
“The tandem charging system GM is patenting would likely be used more for home charging than for public charging stations.”
Really see this for dealers, with an inventory of EVs that need to be maintained in subfreezing weather, and limited stations to do it with. “Charge twice the cars half as fast” wouldn’t be an issue when they just need to be maintained.
So a power strip?
This to me is a bad solution to the wrong problem. They need to start by making it so all when you go to a charge station, that all the chargers work, and don’t have their cables cut.
In theory, if were promised correctly, solid state batteries will cut wait times in half 🤞🏼
The way I’m reading the drawings, this does inadvertently solve part of the problem. It looks like this solution requires new EVs with two charge ports instead of one. The second and third vehicles would bring their own cord to connect to the upstream vehicle. If everyone is carrying their own charging cord already, it’s only a matter of time before the charging stations eliminate their cords to reduce maintenance costs.
Of course, there are a dozen reasons this will never catch on, so I wouldn’t look at this as a real solution.
This could be used if you have multiple EVs at your home. You could have one charger but charge several EVs.
General Motors (GM) has recently filed a patent for a tandem charging solution, presumably under the assumption that an increasing number of families will be purchasing multiple electric vehicles (EVs) and will therefore require advanced multi-charging capabilities. However, this strategic direction appears to be misaligned with current market trends and public sentiment. The demand for EVs is showing signs of stagnation, compounded by the inadequacy of the national power grid, which has not been sufficiently upgraded to accommodate the growing demand for electricity. Furthermore, the new administration has signaled a policy shift, moving away from the aggressive promotion of EVs by rolling back the EV mandate, reducing government subsidies for EV purchases, and encouraging the production of internal combustion engine (ICE) vehicles.
In light of these developments, GM’s focus on expanding its EV portfolio without adapting to the evolving regulatory and market landscape may pose financial risks. To ensure long-term profitability and resilience, the company must critically reassess its EV and ICE strategies, aligning them with consumer preferences, infrastructural realities, and the changing policy environment.
I’m not sure where you’re reading about strain on the power grid, but it’s BS. Most EVs are charged overnight when demand for electricity is lowest.
Charging several cars at once in series would require some mighty heavy cables in order to handle all of that amperage, unless it is just a “trickle” charge.