BMW questions BYD's 'Flash Charging' claims

BMW has cast doubt on the real-world benefits of BYD’s new ultra-fast ‘Flash Charging’ technology, warning that extreme charging speeds can come with trade-offs as the Chinese behemoth pushes toward five-minute refuelling times, rivalling those of petrol and diesel cars.

According to senior BMW battery engineers, the company could pursue higher charging speeds if it chose to, but believes the new i3 and iX3 already charge quickly enough for most real-world use cases.

Conversely, BYD’s new Flash Charging system is one of the most aggressive moves yet to eliminate one of the key pain points for EV owners: time spent recharging.

The second generation of the technology combines BYD’s Blade Battery 2.0, extremely high current delivery and dedicated megawatt-level chargers in China to achieve peak charge rates of 1500kW – fast enough to add about 500km of range, or a 10-70 per cent top-up, in just five minutes.

Speaking with carsales, top executives from BMW said the impressive headline figures hide part of the truth of Flash Charging.

“You always have to be careful with those kinds of announcements,” BMW battery production boss Markus Fallböhmer.

“It is possible to optimise one single performance indicator, but you have to make compromises on other sides.

“We could also increase our charging speed, but then you have to reduce other important factors of a battery. It is a blanket – if you pull it at one side.”

Increasing charging speeds typically requires reductions to energy density and raises thermal management issues, which impact long-term durability if not carefully managed.

Mike Reichelt is BMW’s head of Neue Klasse models, which currently peak at 400kW charging speeds.

“We look to decrease charging time more and more, but you have to look at range, durability, reliability,” he said.

“All of these facts, we guarantee. We look at the speed of the Chinese market … but on the other side, we guarantee quality and safety. That is a topic that we do not [negotiate] with anyone.”

Despite that, BYD’s Flash Charging appears to represent a meaningful step forward.

Average charging power during a BYD Flash Charging session appears to exceed 600kW, approximately double the average speed of the quickest charge for a Neue Klasse model.

The upcoming BMW i3 can replenish 400km of driving range in 10 minutes at a session average charging speed of roughly 290kW – fast enough according to BMW.

“You have to decide whether you go to the toilet or get a coffee. You don’t have time to do both,” Reichelt said.

The view at BMW is that Neue Klasse charging fits comfortably within a typical rest stop, with further gains bringing costs of their own while diminishing real-world benefits to buyers.

That logic makes sense for most private buyers, particularly when doing long distances on highways, where 15-minute rest stops are already aligned with fatigue management.

BYD’s push into five-minute Flash Charging matters most in edge cases.

Shorter stops reduce waiting times at busy chargers, improve utilisation for taxis and fleets, and bring EVs closer to parity with petrol and diesel refuelling.

BYD’s approach represents a different way of thinking about charging, with the brand replacing existing infrastructure to build an integrated charger and battery system of its own.

By contrast, BMW has focussed its efforts on working within the constraints of the 800-volt chargers already available in Europe, North America and Australia.

A circuit-breaker could be the fact that BYD intends to bring Flash Charging to Europe in the near future by building its own charging network, potentially putting vehicles like the Denza Z9GT into more direct competition with the BMW i3.

For now, there’s no word on an expansion of BYD Flash Charging into Australia, where the technology could help close the gap further for long-distance driving across the continent.

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