An imminent breakthrough in the mass production of solid-state batteries could significantly cut electric vehicle charging time and extend driving range, bringing the auto industry closer to overcoming major hurdles for widespread EV adoption.
Most EVs on the road today are powered by lithium-ion batteries, and their popularity is growing amid a wider push to reduce transport emissions. But some drivers are still reluctant to switch from fossil fuel-burning cars to EVs, citing range anxiety, charging time, and the risk of catching fire among their top concerns. (Even though all of those questions are mostly easily answered.)
Experts say solid-state batteries (SSBs) will be a potential “game changer” to address these issues, the Financial Times reported in October. Toyota’s “headway in manufacturing technology” could enable it to mass-produce SSBs by 2028.
“If successful, Toyota expects its electric cars powered by solid-state batteries to have a range of 1,200 kilometres—more than twice the range of its current EVs—and a charging time of 10 minutes or less,” the Times said.
The technology could boost EV uptake—as one BMW Blog post stated, “industry analysts strongly believe that solid-state batteries are the breakthrough that EVs need to explode in popularity.”
Pluses and Minuses
The main difference between lithium ion and solid-state batteries is the composition of the separator that lies between the negatively charged cathode and positively charged anode. The separator serves a critical function in all batteries by preventing physical contact of the anode and cathode—which would short the battery’s circuit—while still allowing electrons to flow between the two when the battery either stores or releases a charge.
The separator in a lithium-ion battery is composed of a liquid electrolyte, while an SSB’s electrolyte is solid. This difference reduces fire risk and, depending on how thin manufacturers can make the separator, can lead to faster charging times.
The solid separator also gives SSBs a comparatively greater energy density per weight or volume. As EV batteries are massive components of a vehicle, being able to hold an equivalent charge with less weight allows the car to be powered for longer. As Motor Trend explains, an average 80-kilowatt-hour battery pack in an EV today weighs about 1,000 pounds can be matched by a 80-kWh solid-state pack that would weigh just 333 pounds. With less weight, EVs will have greater range.
SSBs can also significantly cut down on construction time—a key determinant of overall costs—by reducing the steps to build the battery. Lithium-ion battery construction includes a filling and conditioning phase where the liquid electrolyte is applied, in which “you gently, gently charge and discharge the battery, allowing the electrodes to form their protective coating, almost like a preparation for the battery to enter its normal life,” explained Rory McNulty, research analyst with Benchmark Mineral Intelligence.
“Now, with a solid-state separator, you don’t need those steps, so you remove up to three weeks of processing time from your manufacturing line.”
But SSBs production still comes with its own complexities. The units are expected to rely on the same critical minerals—and perhaps a greater quantity of them—that are already in high demand for lithium-ion batteries and other clean energy technologies. So recycling SSB components will still be crucial.
And while SSBs can reduce the steps in construction, manufacturing them is not without challenges. Assembly can be complicated, considering the components’ sensitivity to oxygen and moisture. And the higher density of rare minerals, combined with the up-front expense of overhauling manufacturing infrastructure, could create high costs for SSBs at first, Motor Trend writes.
“The first commercialization of a solid-state battery will not be cost-competitive with [today’s] lithium-ion batteries; it will come at a cost premium,” McNulty said. “But those benefits in safety and drive range and that kind of thing would likely make up for that. It’s over time, over the first five to 10 years of commercialization, that it will begin to become cost-competitive as the technology improves.”
Toyota promised to roll out SSB-powered EVs by the latter years of this decade, holding back on pursuing other EV technologies. The automaker has missed some of its own development deadlines in the past, but in July it announced a breakthrough on durability concerns and said it was developing the means to mass produce SSBs.
It’s a new look for an automaker that had previously bet big on hydrogen vehicles, sought to block climate regulations, and opposed a full-on transition to electric vehicles.
“With repeated efforts involving trial and error, we have succeeded in developing a material that is more stable and less prone to crack,” Toyota CEO Koji Sato told reporters. “By combining this new solid electrolyte with the Toyota Group’s cathode and anode materials and battery technologies, we are now on the path toward achieving both performance and durability in solid-state batteries.”
In October, Toyota and Japanese petroleum company Idemitsu Kosan announced a partnership to mass produce the batteries beginning in 2027-2028.
“The future of mobility lies in the tie-up between the auto and energy sectors, including this innovation hailing from Japan,” Sato told reporters in Tokyo.
In their agreement, the two companies said they would work together on “developing mass production technology of solid electrolytes, improving productivity, and [establishing] a supply chain, to achieve the mass production of all-solid-state batteries for battery electric vehicles.”
The collaboration will focus on sulphide solid electrolytes—Idemitsu’s petroleum refining division produces sulphides as a byproduct, and the company has reportedly been researching sulphide-based SSBs since as early as 2001, and the two companies have been collaborating on that work since 2013.
“Toyota holds the patent for the material’s components,” writes the Toyota Times. “At the same time, Idemitsu’s strength lies in its technological capabilities for producing materials with high water resistance, ion conductivity, and flexibility.”
“This collaboration enables the companies to integrate their materials development technologies, Idemitsu’s materials manufacturing technology, and Toyota’s battery mass production technology,” the automaker’s in-house newsletter added. “In other words, it will bring together all aspects of the process, from materials to finished batteries.”
Toyota says the battery will have a driving range of around 1,200 kilometres and will charge in 10 minutes—solving the frequently-cited challenges of EV ownership, if the claims materialize. One caveat: the automaker aims to have SSB vehicles in production by 2027, but plans to produce only a few thousand in the initial years, with production increasing into the next decade.
With their potential application in EVs, SSBs have been attracting investment. The global SSB market grew from US$340 million in 2022 to $490 million in 2023, and is expected to exceed $2.4 billion in 2027.
And Toyota isn’t the only automaker pursuing SSB technology. The Toyota-Idemitsu partnership accounts for a large share of SSB-related patents. But automakers Hyundai, Kia, and Honda are all working on their own SSB research, while others—including Ford, Volkswagen, and BMW—are working with external battery manufacturers to develop them, Forbes says. Battery manufacturers and universities are also doing their own independent research.
So mass production of SSBs is still several years away, McNulty said, with 2030 an “optimistic suggestion” and 2032 to 2035 a more realistic estimate for when they might be available to consumers.
And if SSBs are to be mass produced for EVs, their recycling and supply chains must advance in step, McNulty told Motor Trend. Expanded charging infrastructure will also be essential for more widespread EV use, and SSBs will also have to compete for investment against alternatives like improved lithium-ion designs and sodium-ion batteries, writes Top Speed.