The batteries which can power UAM vehicles are already in production – but they will never compete with the energy density of fossil fuel

Battery power is one of the biggest obstacles to the emerging UAM market.

Phil Whiffin, Head of Advanced Propulsion Systems at WMG, University of Warwick, talked to FINN about recent progress in one of the sector’s greatest challenges – battery propulsion. WMG’s Energy Innovation Centre undertakes research and development on batteries, often in conjunction with OEMS and battery suppliers. The facility enables manufacture of battery material, cells and packs.

Whiffin said: “Batteries are the big constraint to any vehicle: they define how far you can go, how fast you can go.”

He added: “People will always want more. They will always want to drive further, fly further and they’ll always want to go faster and the battery constrains that.

“We’ve made massive progressive in the last few years. Batteries have come down in cost four times. We’ve got the energy density and power density to 280w per kg which is really quite impressive.”

Batteries will “never compete” with fossil fuel

But Whiffin said the lower energy density of batteries meant they would never be able to compete with the power of fossil fuel propulsion.

“We are not ever going to compete with fossil fuel. The energy density of the battery is always going to be 40 to 50 time less than the equivalent of fossil fuel, so you’re going to have to change your behaviour. That will affect the vehicle and the way the vehicle operates, but we are making great progress.”

Whiffin said vehicle design would have to move away from batteries dropped following design stage to having the battery designed as part of the mission profile, to make the most of efficiencies.

When asked whether batteries would be able to power UAM vehicles in the next decade, he said this was already possible for short flights. He also added that he would feel safe flying within these vehicles: “I am absolutely 100% optimistic. The batteries are there today that will fit particular mission profiles. If you want to fly 35 miles you will be able to do it, its if you want to fly 70 miles, 100 miles, you start to struggle. But given mission profiles, absolutely, you could do it today. I actually feel safer in the air than I do in a car.”

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