Lilium is partnering with the lithium-ion battery developer Customcells to manufacture the high-performance silicon-anode batteries for its seven-seat eVTOL Lilium Jet.
Using Lilium’s licensed technology, Customcells plans to manufacture the batteries at its facility in Tübingen, Germany, around 200 kilometers (125 miles) from Lilium’s headquarters near Munich. According to Lilium co-founder and CEO Daniel Wiegand, Customcells’ expertise will be critical to ensuring the quality and traceability of the batteries as Lilium scales up production of its fully electric aircraft.
“We’ve been working for several years on getting the right batteries for Lilium and also getting the right supplier for us who can produce these batteries in the right scale and quality for aviation,” Wiegand told eVTOL.com. Customcells has already demonstrated “very high standards” in manufacturing and traceability, he said, and “having the highest possible standard is crucial for us from a safety perspective and from an operational reliabilities perspective.”
According to Customcells co-founder and CEO Leopold König, his company expects to build the first prototype cells this year. Lilium has said it plans to conduct ground and flight testing of its seven-seat model in 2022 and 2023, with certification and entry into service targeted for 2024. Lilium’s earlier prototypes used different, off-the-shelf cells, Wiegand said.
Customcells was spun off from Germany’s Fraunhofer Institute in 2012 and produces batteries for automotive and other industries. Last month, the company announced a joint venture with Porsche called Cellforce Group, which will manufacture silicon-anode batteries for high-performance racing cars.
On July 26, Porsche Ventures was announced as an investor in Customcells, along with Vsquared Ventures and 468 Capital. In a press release, Dr. Ulrich Thiem of Porsche Ventures noted that “Customcells offers a wide range of potential applications via its investment in Cellforce Group GmbH and the associated synergies, particularly in maritime and vertical electric mobility.”
Lilium will be asking a lot from its batteries. Not only will its seven-seat Lilium Jet have a much higher disc loading than most of its competitors — thus consuming more energy in a hover — the company is also targeting regional air mobility missions that are comparatively long-range. For example, Joby predicts that its average trip length will be just 26 miles (42 kilometers), but Lilium expects to fly trips averaging 60 to 75 miles (95 to 120 km).
In recent filings with the U.S. Securities and Exchange Commission, Lilium confirmed that it will be using large-format lithium-ion pouch batteries with a cell chemistry based on a silicon anode combined with conventional nickel-manganese-cobalt (NMC) cathodes and liquid electrolytes. Lilium claims to have secured exclusive rights for this chemistry in the eVTOL market, but Wiegand clarified that the exclusivity refers to certain third-party intellectual property, not the agreement with Customcells.
König told eVTOL.com that while Customcells is remaining open to the possibility of working with other aircraft developers, for the time being, Lilium is its “preferred partner” in electric aviation.