While the aviation industry has sought to make more fuel-efficient designs, the heavy weight of traditional lithium-ion batteries has prevented aircraft makers from following in the footsteps of car companies in building electric engines.

"With this new program, we will build certifiable battery systems enabling greatly enhanced aircraft performance," Cuberg's Chief Executive Richard Wang said in a statement.

The company has begun testing the battery system which it said is light enough to be installed on a plane to make electric flying safe and sustainable.

Northvolt and Cuberg in July 2022 said they had made a breakthrough in developing the lithium metal battery to have cell lifetimes long enough to be used to cover longer distances and carry heavier vehicles.

(Reporting by Essi Lehto, editing by Terje Solsvik)