Belgian high-tech joins forces in aviation solid-state battery

Belgian aerospace company Sonaca joins the Limburg-based start-up SOLiTHOR to develop solid-state batteries for regional aviation and future air taxis (VTOLs). Solid-state batteries are lighter, have more energy density, and are considered safer than current lithium-ion batteries with a fluid electrolyte.

SOLiTHOR will be responsible for cell research, development, testing characterization, format design, and production in a rented production hall at Punch Powertrain in Sint-Truiden. In Gosselies (Charleroi), Soneca will develop the battery packaging, including all related aviation management systems, to certify the battery system.

Unique electrolyte

The Limburg start-up is a spin-off of the Leuven-based research company Imec, with its R&D center and labs based at the Thor site at the former coalmine of Waterschei in Ghenk. Hence the ‘THOR’ in its name. It has been working on solid-state battery technologies aimed at automotive, aviation, and maritime for several years.

In December 2022, it concluded a 10-year contract with Punch Powertrain to establish a European Centre of Excellence for solid-state lithium batteries at Punch’s factory in Sint-Truiden.

SOLiTHOR developed a unique electrolyte for lithium-ion cells that starts as a liquid and becomes solid in the production process, which promises easy and cheaper manufacturing. The company says that the liquid-to-solid process results in a ‘drop-in’ solid electrolyte, which does not require an expensive rebuild of classic cell product lines.

Region aircraft and VTOLs

Technically, it’s called “a nano-Solid Composite Electrolyte (nano-SCE), which is neither a sulfide, an oxide, nor a polymer and does not need high operating temperatures to reach high lithium-ion conductivity combined with a lithium nano-anode.”

With Sonaca, a world-known aviation and space technology specialist that builds parts of the F35 fighter plane, among others, SOLiTHOR will focus primarily on electric aircraft for regional transport and air taxis that take off and land vertically (VTOLs).

Lightweight is crucial

Current lithium-ion batteries remain heavy, have a fire risk, and power for take-off and landing is intensive, which dramatically reduces flight time. Hydrogen, burned in jet engines or used in fuel cells, is another option, but its storage and safe distribution are a worry, the researchers say.

“Considering that aircraft battery systems will most likely operate within a range of between 150 and 500 kWh, inherent safety and being lightweight is crucial to the success of our technology.” For instance, they typically aim at regional planes with a five-hour flight range.

They think it’s very likely that their battery cells will be deployed into regional aircraft within the next 3 to 5 years. Joining forces with a big player like Sonaca will increase the chance of reaching that deadline.