At the foot of the Alps, in Voreppe in Isère, Limatech pushes the walls of its premises. Two-time winner of the investment plan France 2030, this young company born in 2016 will move to industrial scale.
By the end of 2024, three production lines are expected to be in operation. But before that, the team of about thirty employees is working to certify its new battery model.
Limatech proposes to replace the lead-acid or nickel-cadmium batteries currently used by aviation with a new model, less toxic to the environment, according to the company.
The technology, resulting from a transfer from the CEA-Leti research center, is based on a lithium-iron-phosphate battery, which will be used to start aircraft engines, turbines, but also for the power supply on board.
According to Maxime Di Meglio, co-founder and CEO of Limatech, this new generation battery has several advantages, foremost among which is a lower mass.
"Our battery weighs 6.5 kilos against 16.5 kilos for nickel-cadmium and 17 kilos for lead," he explains. A far from negligible gain in an airplane, when each extra kilo on board requires more kerosene.
With this option, says Florence Robin, the president of Limatech, the weight gain can even reach "25 kilos for a helicopter and up to 120 kilos on an A320".
Equipping long-haul aircraft is also one of the stated objectives of the start-up, which will start flights next year on smaller models. Limatech has an energy density – the amount of energy that can be stored in a given mass – three times higher than lead and nickel-cadmium batteries, she says.
Above all, its engineers have developed a system to avoid thermal runaway, a risk traditionally associated with lithium batteries and which explains the difficulties in using them on aircraft.
The proposal is promising and Limatech, winner of Airbus' aeronautical innovation in 2019, aims to produce 3,500 batteries per month in 2030 for all types of aircraft, for a turnover that could approach 200 million euros per year.
For the moment, however, production is far from having reached this cruising pace at the Voreppe site. Limatech is currently in the qualification phase, with a total of 46 high-level tests to pass.
Among these tests, a battery will remain for several hours at -40 ° C in an oven of the workshop.
"One of our innovations is to integrate a heater into our battery," explains Maxime Di Meglio, a system that allows the batteries integrated into the battery to be put at the right temperature.
Research is intensifying in the field of lithium batteries and other companies have embarked on the adventure.
Lithium batteries for aeronautics produced at the Limatech plant in Voreppe near Grenoble, June 12, 2023 © OLIVIER CHASSIGNOLE / AFP
Swedish battery manufacturer Northvolt unveiled its own program at the end of April, through its subsidiary Cuberg, which develops a lithium battery for aviation.
China's CATL (Contemporary Amperex Technology), another major producer of electric batteries for the automotive industry, recently announced the development of a "condensed-matter" lithium-ion battery that could be used for aviation.
But flying large planes only by electric batteries seems a dream still distant, say the founders of Limatech.
"Many are thinking about battery-electric propulsion. However, today, operating aircraft solely by battery is not possible with regard to existing technologies," says Maxime Di Meglio.
"We are in the infancy in terms of batteries for propulsion. There is not much that flies electrically, apart from tourist planes and small drones, and that for not very long," abounds Gaëtan Monnier, mobility director at IFP Energies nouvelles (Ifpen).
Because the hydrocarbons currently used in aviation are difficult to compete in terms of energy density. This is one of the disadvantages, not to mention the need to ensure an optimal level of safety, without risk of thermal runaway, says the specialist.
While waiting for future innovations, Limatech is already in negotiations with major aircraft manufacturers.
© 2023 AFP