In its Dare Forward 2030 electrification plan, Stellantis reaches a new milestone. The automotive group, which had already announced for autumn 2024 a strategic partnership with American start-up Factorial Energy, today confirms validation of its first solid electrolyte cells for the automotive industry. These batteries promise to outperform current lithium-ion batteries, will be tested in a pilot fleet of vehicles from 2026.
Higher energy density for more efficient vehicles
Developed using FEST (Factorial Electrolyte System Technology), the new validated cells boast an energy density of 375 Wh/kg, significantly higher than traditional lithium-ion cells (around 300 Wh/kg) and even some semi-solid batteries (up to 360 Wh/kg). In concrete terms, according to Quentin Laporte, an electrified motorization engineer whom we interviewed on this subject, this would make it possible to envisage a 100 kWh pack weighing 450 kg, compared with around 600 kg at present, a significant weight saving in terms of range, roadholding and performance.
Accelerated recharging and extended climate tolerance
Another major advance is the charging speed. Stellantis and Factorial claim a recharge time from 15 % to 90 % in just 18 minutes, at room temperature. A figure which, while not revolutionary compared with today's best systems, remains highly competitive, especially for a technology still in development. Added to this is increased resistance to extreme temperatures, with guaranteed operation from -30°C to +45°C, a much wider range than conventional batteries.
Lifespan and safety: the two challenges met
The black spot often mentioned for solid-state batteries - service life - also seems to be on the way to being resolved: validated cells have reached over 600 charge cycles, where conventional lithium-ion batteries average between 1,500 and 2,000 cycles. This figure, although still low, nevertheless represents a considerable advance for a lithium-metal battery, and testifies to the rapid progress of this still young technology. Safety, often put forward by solid-state proponents, is also a strong argument, thanks in particular to improved thermal stability.
Technology soon on the road
Stellantis has announced that this new generation of batteries will be integrated in a fleet of demonstration vehicles in 2026, notably on the STLA Large platform, designed for top-of-the-range and sporty models. These tests will enable the technology to be validated in real-life conditions, prior to eventual mass production.
In addition to Stellantis, Factorial Energy is also working with Mercedes-Benz, Hyundai and Kia, demonstrating the enormous interest in this technology. While no precise date for mass production has yet been announced, steady progress since 2021, when Stellantis first invested in Factorial ($75 million), shows an ambitious but realistic roadmap.
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