this post was submitted on 15 Sep 2023
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Fully Charged in Just 6 Minutes – Groundbreaking Technique Could Revolutionize EV Charging::Typically, it takes around 10 hours to charge an electric vehicle. Even with fast-charging techniques, you're still looking at a minimum of 30 minutes – and that's if there's an open spot at a charging station. If electric vehicles could charge as swiftly as we refill traditional gas vehicles, it wo

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[–] [email protected] 43 points 1 year ago* (last edited 1 year ago) (32 children)

Alright, so let's assume a 100kWh battery like some tesla models. Now, someone made such a battery that can be charged in 6 minutes... how much power does it need?

100 kW•h / 6minutes = 100kW•h / 0.1h = 1000kW = 1MW

So, we need 1 MEGAWATT car chargers ... that's some power required there.

[–] [email protected] 26 points 1 year ago (9 children)

Possibly even more significant, those are some large cables and even larger contacts required. There's no way a 1MW disconnect is just a little plug you stick into your car.

In fact as an electrician I can't think of anything even near megawatt class that would be connected with a portable cord, or at a voltage that would be safe for consumers to handle.

Maybe someone in the mining industry or similar can chime in, but I currently run a pumping station that includes 3000HP motors (2.2MW). These are 4kV 3 phase units where each phase cable is as thick as your arm. All connections are bolted and taped to avoid corona discharge. Just dragging the cable to the car would be more than the average driver could handle.

I don't see a way to get these power levels into a car short of a standardized and semi-automated docking system. Or maybe go back to the idea of standard swappable batteries where the battery then is charged rapidly for the next customer.

[–] [email protected] 16 points 1 year ago* (last edited 1 year ago)

The power lines in the cable are disconnected inside the charger by a contactor until communication with the car is confirmed established with a handshake, and then it connects power to the cable. If the communication with the car drops at any point, the contactor disconnects the power to the cable. It requires both effort and knowledge to bypass this design, it basically can't happen accidentally.

Also, the cables you mention are that large, because they're passively cooled, DC car chargers have watercooled cables so they can be much thinner without overheating. And at 4kV you're looking at significantly different insulation thickness as well, compared to the 400-800V that electric cars use.

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