Electric car: the uncertain revolution of “solid” batteries

It’s the new holy grail in the automotive industry. Since manufacturers have resolutely embarked on the shift towards electric vehicles, the so-called “solid” battery has become the new frontier to cross. All manufacturers, or almost, have announced strategic partnerships or significant investments in this area – even if the solid electrolyte is still far from collapsing.

Volkswagen has already invested $ 300 million in the California company QuantumScape, also backed by Bill Gates, created in 2010 and listed since the end of 2020. Ford and BMW, for their part, have invested $ 135 million in Solid Power, born in 2011 from a spin-off from the University of Colorado, which itself raised $ 540 million by being listed last year.

The builders place their peasants

Other examples include the start-up Factorial Energy, which welcomed industry leaders such as Dieter Zetsche (formerly Daimler-Mercedes chief) and Mark Fields (former Ford chief) to its “board” before concluding a $ 200 million seed round last January . of Stellantis and Mercedes-Benz.

The latter also announced last February a partnership with Taiwanese unicorn ProLogium. And the two manufacturers depend on their subsidiary in batteries ACC (Automotive Cells Company), owned by Saft (Total group), to develop “solid” batteries.

The list is far from exhaustive. “Producers place their farmers by collaborating with specialists,” says Eric Kirstetter, partner at Roland Berger. In the current knowledge, ‘solid state’ is the most promising technology to increase the energy density of batteries, but also to reduce the risk of fire. »

In current lithium-ion batteries, it is a liquid that conducts the ions so that they can move from the anode to the cathode (to power the motor) or vice versa (during recharging): they must replace this liquid with a solid material (ceramic or polymer). “The solid electrolyte eliminates the potentially flammable liquid,” explains Philippe Biensan, Technical Director at ACC.

Higher energy density

“The ‘solid state’ shows great stability in the face of temperature variations, so it is much safer,” adds Gilles Normand, a former Renault manager who joined ProLogium. “It also allows you to charge at least twice as fast. »

The research concerns not only the material of the electrolyte, but also the composition of the electrodes approved by the “solid state”. “A metallic lithium anode, for example, makes it possible to increase the energy density and thus the batteries’ autonomy for a corresponding volume,” states Philippe Biensan.

QuantumScape, which has made this choice, estimates that the autonomy of vehicles could thus increase by 50 to 80%. With ProLogium batteries, which rely on a ceramic electrolyte, it can be doubled, says Gilles Normand.

It is also a matter of dispensing with rare materials, such as nickel or cobalt, used today for cathodes whose prices have risen sharply recently. “There are many research paths in parallel,” insists Philippe Biensan. The effort is huge when we know that the battery represents up to 40% of the value of electric cars.

Many obstacles

However, many obstacles still exist. Even apart from the cost, it is necessary to find sufficient conductive materials for the solid electrolyte. “We also need to improve the design of the cells so that they are more resistant to aging and that the transformations of the material that are likely to create short circuits are eliminated,” explains Eric Kirstetter. In addition, manufacturing on an industrial scale also poses a significant challenge. »

The first to reach mass production will have a huge competitive advantage. It will be a true technological breakthrough.


The race is underway. Traditional battery manufacturers (SK Innovation, LG Chem, Panasonic, CATL) are not left out, as are chemists, national research centers or universities. “The first to reach mass production will have a huge competitive advantage,” says one industrialist. It will be a true technological breakthrough. »

Flying objects

However, it is difficult to make predictions. Toyota, which had announced solid batteries in its cars for the 2020 Olympics in Tokyo, had to go back: The Japanese giant now plans to start introducing them in its hybrid cars by 2025. “We need to see what really matters. behind the announcements, ‘breathes a player in the sector.

Each has its benefits. QuantumScape or ProLogium, for example, are announcing for 2025 their first giga factory capable of marketing solid batteries for electric cars. “We already have a pilot plant since 2016 (which currently produces batteries for portable devices), and we will start a first mass production at the end of 2022, to define the industrial process,” insists Gilles Normand, at ProLogium. Solid Power has just announced the start of a pilot production line that will deliver its first cell samples to its partners BMW and Ford for testing at the end of 2022.

“In 2025, we will no doubt see the first industrial prototypes arrive. Mass production will probably not happen until 2028, according to Eric Kirstetter. Solid-state batteries will definitely start by first equipping premium cars, which are more likely to absorb the extra costs associated with it. »

Also planes?

They could even be of interest to other sectors. “Their safety authorizes them, for example, in flying objects,” says Gilles Normand. “We are already in contact with manufacturers in this area,” he says.

According to the Fraunhofer Institute in Munich, which has just published a study on the subject, the production capacity for solid state batteries should be between 15 and 55 GWh in 2030 and between 40 and 120 GWh in 2035, ie. “1% or 2% of the total capacity of lithium-ion batteries that will have occurred on these dates.” The race feels less like a sprint than a triple marathon.

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