Energy Transition

'We prefer liquid hydrogen for trucks' | Daimler begins test of LH2 prototype with aim to sell 1,000km-range lorries by 2030

Company is also working on ‘subcooled’ liquid H2 process that would enable even longer journeys on a single tank

The liquid-hydrogen-powered Mercedes-Benz prototype.
The liquid-hydrogen-powered Mercedes-Benz prototype.Daimler Truck
Daimler Truck, an offshoot of Mercedes-Benz, says it has begun testing the first ever liquid-hydrogen (LH2) truck at its test track in the German town of Wörth am Rhein.
All hydrogen-powered vehicles manufactured to date — as well as refuelling pumps — have used gaseous H2 compressed at either 350 or 700 bar.

But the German company says it “prefers liquid hydrogen in the development of hydrogen-based drives”.

“In this aggregate state the energy carrier has a significantly higher energy density in relation to volume compared to gaseous hydrogen,” it explains. “As a result, more hydrogen can be carried, which significantly increases the range and enables comparable performance of the vehicle with that of a conventional diesel truck.”

Compressed hydrogen at 350 or 750 bar contains 0.8 or 1.1kWh of energy per litre, respectively. But liquefying the gas — by lowering its temperature to minus 253°C — increases the volumetric energy density to more than 2.3kWh/litre. This means that a fuel tank containing liquid H2 would contain about two to three times more energy — and therefore range — than a similar-sized tank containing compressed hydrogen.
This is why industrial gases company Linde has described LH2 as the “holy grail” for unlocking hydrogen use in the mobility sector.
Daimler’s prototype Mercedes-Benz truck uses an LH2 refuelling system provided by Linde rival Air Liquide to fill two 40kg tanks mounted on either side of its chassis.
Refuelling the Mercedes-Benz prototype with liquid hydrogen.Daimler Truck

“Thanks to the particularly good insulation of the vehicle tanks, the hydrogen can be kept at temperature for a sufficiently long time without active cooling,” the company says.

“The development objective of the series-ready GenH2 Truck is a range of up to 1,000km and more,” it adds. “This makes the truck suitable for flexible and demanding applications, especially in the important segment of heavy-duty long-haul transport.

“The start of series production for hydrogen-based trucks is planned for the second half of the decade.”

Subcooled liquid hydrogen

Daimler Trucks is also working with Linde on a new process for handling subcooled liquid hydrogen (sLH2) — ie, H2 that has been cooled beyond 253°C, increasing the volumetric energy density (and therefore driving range) even further.
“Among other things, this innovative approach enables even higher storage density and easier refuelling compared to LH2,” the company says.
The two companies are planning to fuel the first prototype sLH2 truck at a pilot refuelling station next year.
“Daimler Truck and its partners are planning for a high level of transparency and openness around the relevant interfaces of the jointly developed sLH2 technology,” the German company explains.
A closer look at one of the two liquid-hydrogen fuel tanks.Daimler Truck

“The goal is to collaborate with other companies and associations as possible to develop their own refuelling and vehicle technologies that apply the new liquid-hydrogen standard and thereby establish a global mass market for the new process.”

Daimler Truck was spun off last year from the Mercedes-Benz group, which is still its biggest shareholder, owning 30.01% of the new company.

The business sells trucks under five brands — Mercedes-Benz, India-focused BharatBenz, Asia-based Mitsubishi Fuso, US manufacturers Freightliner and Western Star — while it also produces buses under the brands Mercedes-Benz, Setra, BharatBenz, Fuso and Thomas Built.

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Published 29 July 2022, 09:15Updated 29 July 2022, 09:15
DaimlerGermanyTransportEurope