Does the Mercedes EQXX concept signal a shift to air cooling for electric vehicle batteries?


In the Mercedes-Benz Vision EQXX concept car unveiled earlier this week, range took center stage, with claims of an incredible 621 actual miles (or more) from a battery of less than 100 kwh, or more than 6 miles per kwh in terms of efficiency.

Achieving this efficiency required an F1-like level of attention to an array of intriguing technological details, literally drawing on the company’s experience in F1 racing on multiple fronts and involving personnel accustomed to settle the Nürburgring as much as the neighborhood.

And yet the EQXX’s battery – one of many that executives say is likely production related – takes an approach not used by F1, Formula E or any of the other vehicles. modern electrics from Mercedes: passive cooling, otherwise known. as air cooling.

Mercedes Vision EQXX EV Concept

As Daimler AG Chief Technology Officer Markus Schäfer explained after the reveal, this is achieved through intelligent cell management throughout the pack, combined with an integrated cooling pad at the bottom, as well as vents that open when the temperature rises.

Simply put, running pumps and circulating liquids in typically two-circuit cooling systems costs energy and efficiency.

During a question-and-answer session on Tuesday, Adam Allsop, director of advanced technologies for Mercedes-AMG performance powertrains, gave some additional details beyond this high-level view of how the team is doing. come to passive cooling. And he called the pack’s design and its performance parameters a “virtuous circle” around efficient cells.

A virtuous circle that keeps its cool

“The fact that we’re not looking for very high performance means we’re not stressing the cell,” Allsop explained to Green Car Reports, and that means they could opt for the passive cooling option. “It meant we could really work to reduce the battery profile and fit a huge amount of power into a very small space.”

Mercedes-Benz claims an energy density of almost 400 watt-hours per liter at the pack level – not on par with the energy density of cylindrical cell packs such as those used by Tesla, but far better than other packs current ones using its prismatic cell format.

Mercedes EQXX concept battery

Mercedes EQXX concept battery

The new strategy is part of a cell-to-pack battery format that has been directly influenced by F1, with a 20% increase in cell energy density and an overall pack that is 30% lighter and half that of of the EQS. The company said other vendors are involved in the project, including CATL, which provides cells for the EQS.

And yet, passive cooling or air-cooling is extremely rare among modern EVs today – encountered only by the Nissan Leaf, among newer models, and in a few other used EVs, including the Volkswagen e-Golf. .

Leaf’s lessons?

A decade ago, Tesla CEO Elon Musk called out Nissan’s cooling approach to the primitive Leaf, at a time when the Tesla Roadster and Chevy Volt’s liquid-cooling systems were considered outdated. the cutting edge of technology. Musk accurately predicted that the Leaf’s pack would experience “tremendous degradation” in cold weather and could essentially “die out” in hot weather, though Nissan has improved along the way with some changes in chemistry.

Mercedes Vision EQXX EV Concept

Mercedes Vision EQXX EV Concept

To this, the Mercedes team says there is still real-world testing to be done, especially when the brand is known for the longevity of its models. “We’ve done single cell testing on development cells, and we’ve done battery level testing, but we haven’t done full life testing yet,” Allsop summarized. “That’s part of what we’ll also learn as we start testing EQXX more.”

As executives emphasized with the introduction of the EQXX, most, if not all, of the key technology elements on display in this concept are production-related, most of them for the modular MMA architecture that will underpin the mass production of compact to midsize electric vehicles. later in the decade. So while air cooling isn’t locked in yet, there must already be a relatively high level of confidence in the decision.

It’s funny how some things come full circle. Liquid cooling was once the innovation. Now innovation may mean getting rid of the need for liquid cooling, at least for cars that aren’t performance oriented.


About Author

Comments are closed.