Recharge in 5 minutes: How Does This New Technology Really Work

Paris, BYD promises with the Denza Z9GT a 5-minute recharge to compete with a full tank of gasoline. Behind this slogan, a much more complex electric mechanism.

An electric car that recharges almost as fast as a full tank of gasoline: on paper, this still looks like a salon promise. However, that’s exactly what BYD is putting forward with its high-end Denza brand and its large sedan-break Z9GT, unveiled in grand style in Paris. Amid the gilding of the Opéra Garnier, Stella Li, executive vice president of the Chinese giant, declared: “This car will redefine your driving experience.” Intriguing anyone who finds fast charging stations still too slow.

Behind the scenes, BYD presents a very simple promise for the driver: stop for a few minutes, leave with a battery almost fully charged, even in winter, and a range of about 600 km. To achieve this, the manufacturer has developed a new technology called Flash Charging, which combines a specific battery, in-house electronics, and ultra-powerful charging stations. It remains to be seen how this cocktail actually manages to do what others don’t offer yet.

For BYD, the stakes are clear: reassure those who fear spending too much time plugged into a charging station. Diego Pareschi, Director of Electric Vehicle Charging for Europe at BYD, based in Amsterdam, stated, “This resolves the main problem that many detractors raise against the adoption of electric vehicles: long charging times.” The Denza Z9GT comes with a 122 kWh battery, and according to the manufacturer, this battery can go from 10% to 70% in five minutes, then reach 97% in nine minutes. BYD even claims that these times “compete with the traditional refueling time at a gas station.”

This results in an advertised range of about 600 km on the WLTP cycle, just a little more than a Porsche Taycan given up to 590 km. The difference lies in the charging station: a Taycan goes from 10% to 80% in 18 minutes, according to Porsche, while BYD promises 10–70% in 5 minutes for the Z9GT. And the Chinese brand particularly emphasizes winter conditions. Even in extreme cold, down to -30°C, BYD claims that these times would only be extended by about three minutes. “Charging in cold weather can be extremely painful,” explains Pareschi. “If the battery is not preheated, it can sometimes take two or three hours for a full charge, hindering the adoption of electric vehicles.” The goal here is to keep the stop very short, even when the temperature drops.

In terms of infrastructure, BYD is not talking about a simple charging station slightly more powerful than others. It is a charger with a maximum power of 1,500 kilowatts, about 2.5 times faster than the fastest stations currently in service in Europe. This translates to a charging rate of up to 10 C for the driver, with a compelling promise: “one second of charging would recover 2 km of range.” However, this power does not come directly from the electrical grid. “It is not necessary to provide 1,500 kW of power to the charging point via the network, as much of the energy will be stored to charge the batteries – hence the term ‘Flash Charging’,” details Pareschi.

BYD states that a 200 kW power supply at the station is sufficient: the station acts as an energy reservoir that is gradually filled before being quickly emptied into the car. These stations will first be installed in Denza dealerships, then deployed with third-party operators, and will be compatible with all electric vehicles. BYD even considers connecting its plug-in hybrids to them, suggesting that models from other brands may pay more or be limited if they do not support these power levels. The real test will be to see how often drivers can truly take advantage of the promised 5 minutes to fill their battery.