Chinese auto manufacturer BYD says it has developed technology that speeds up electric vehicle battery charging to as little as 5 minutes at 1,000 kilowatts, providing enough energy for nearly 250 miles of driving.

Fast charging is viable, but experts say building the actual charging stations will be the tricky—and potentially very expensive—part.

Central to the Han L’s fast charging is its internal electrical infrastructure. It starts with the battery, which according to CarNewsChina citing regulatory documents, is an 83.2 kWh lithium-iron-phosphate (LFP) pack that operates at 945 volts. (In its marketing materials, the company appears to have rounded up and lists it at 1,000 volts).