When it comes to buying an electric car, two concerns often deter prospective buyers: driving range and battery safety. Solid-state batteries, which rely on safer, solid electrolytes, have long held the promise of lower fire risk and extended range. Yet, despite years of development and investment, these next-generation batteries have yet to become a reality.
For the world’s battery makers that have bet big on the new technology, the clock is ticking as the sector faces squeezed margins and slowing EV sales growth in developed markets. An interim solution addressing safety concerns could provide a lucrative opportunity while buying them more time.
The fear of EV battery fires is often amplified by critics. Data shows EVs are far less likely to catch fire compared with petrol or hybrid cars — there are 25 fires per 100,000 EVs sold versus 1,530 for petrol cars, according to the US National Transportation Safety Board.
But when fires do occur in lithium-ion batteries, they can be more destructive — burning hotter, escalating quickly, and releasing toxic gases — creating a perception of heightened risk. Recent high-profile cases, such as the fire from a parked Mercedes EV, which used a battery made by Chinese maker Farasis Energy, in South Korea late last year have exacerbated fears. The fire took eight hours to extinguish and damaged around 880 other cars in the garage where the vehicle was parked.
Solid-state batteries are presented as a safer alternative, especially in high-impact scenarios such as frontal collision. They contain non-flammable solid electrolyte materials instead of the volatile organic liquid electrolytes in more widely used batteries. Some car and battery makers have started testing prototypes and building pilot production lines.
But mass production could prove challenging in the short term. Materials used in the batteries are more expensive. New manufacturing facilities require significant investment, especially daunting for a sector already running on slim margins. Established lithium-ion batteries, with decades of development and the advantage of economies of scale, pose a significant barrier for the new technology to compete on cost.
In the meantime, it is worth looking at when EV fires are most likely to occur to see where improvements can be made. A total of 511 EV fires occurred between 2010 to the end of last June based on data from 40mn EVs globally, including plug-in hybrids, according to research institute EV FireSafe. The data shows that among fires with identified causes, collisions and road debris accounted for the largest share by far.
This suggests that improvements to the EV’s base structure, using designs and materials that offer better shock absorption during collisions, could help enhance the safety of current lithium-ion batteries — without requiring a complete overhaul of existing battery technology.
CATL, the world’s largest EV battery maker, is one of the companies that has adopted this approach. Its latest focus has been on redesigning the flat, skateboard-like platform with four wheels which serves as the foundation of an EV. The goal is to lower the risk of fires by adding protective functions for the battery, such as the ability to disconnect circuits within 0.01 seconds of a collision and discharge residual energy, as well as using submarine-grade high-strength steel in the chassis. In crash tests at speeds of 120km/h, its new design withstood frontal impacts without catching fire, according to the company.
There is an added benefit for battery makers able to offer these features in a single package. The skateboard chassis of EVs consolidates essential components including the batteries, electric motors and controls into a single base structure. This simplifies the manufacturing process, cutting costs and accelerating timelines for new models. It also expands its target market to include automakers and start-ups looking for a quicker entry into the EV market.
The potential of solid-state batteries to reshape the EV market remains clear. But the longer-than-expected development timeline is adding pressure to battery makers to pursue alternative revenue streams in the meantime. As sales growth in key markets continues to slow, safety-related advancements will become a critical differentiator in driving the next phase of EV adoption.
june.yoon@ft.com