Between hope and hype for Toyota’s “solid-state” EV batteries

As automakers race to develop electric battery-powered cars, they are constantly fighting for anything that will give them the edge over their rivals.

After announcing it expected to produce its “solid-state” batteries as early as 2027, Toyota on Tuesday unveiled ambitions to halve the size and cost of power units for its electric vehicles to make them safer and allow them to charge faster.

But despite the Japanese automaker’s optimism, this holy grail battery technology has long eluded the industry.

Smaller, lighter, safer and faster

From the most expensive Tesla to the cheapest Fiat, electric vehicles on the market use batteries that have liquid lithium ion electrolytes.

The electrolyte allows the current to pass through the battery between the two electrodes ̵[ads1]1; the anode and the cathode – and generates the current.

But electric cars that run on liquid batteries have several well-documented shortcomings, for example that they are very heavy and take much longer to charge than gasoline cars take to refuel. They can also catch fire, especially if the batteries overheat.

So-called solid-state battery technology, which uses a solid electrolyte, has the potential to address these concerns.

The batteries can hold much more power, making them smaller without compromising range. They can charge very quickly without getting hot, which makes them much safer.

Toyota said it expected the electric car powered by solid-state batteries to have a range of 1,200 km – more than twice the range of the current electric car – and a charging time of 10 minutes or less.

Where the anode and cathode meet

Despite years of global investment, the technology is still in its infancy.

It is therefore difficult to set an exact timeline.

Toyota says it believes it can commercialize the technology for a vehicle by 2027. Although this is only four years away, it replaces an earlier target of 2025 that the automaker originally set in 2017 and then confirmed in 2021, when it said it believed it could use the batteries in a hybrid model.

“Top management . . . have asked me if we can really do it [by 2027],” Keiji Kaita, Toyota’s top battery expert and president of its carbon neutrality research and development center, said Tuesday. “But I’m presenting them with evidence while we work on it.”

Despite his confidence, battery researchers have seen timetables pushed back again and again.

“A lot of developers have been saying ‘in five years’ for the last 10 years,” said Victoria Hugill, a battery research analyst at consultancy Rho Motion.

Experts also expect semi-solid batteries to reach commercial use sooner than fully solid batteries.

The main challenge for solid-state battery developers is making solid contact between the electrodes – where the lithium ions are stored – and the electrolytes that facilitate movement between them, she added.

Shirley Meng, a battery professor at the University of Chicago, told a Financial Times conference that solid-state batteries also had to operate under some pressure “to perform at their optimal level,” which remains a technological challenge for manufacturers. “This needs to be resolved before the technology can really take off,” she added.

Looking for the technological edge

Toyota has long been resistant to embracing all-electric cars in the same way that its biggest rivals VW and Ford have.

It claims they are too expensive for developing markets, that charging will be difficult in countries with poor power grids, and that using the world’s limited lithium resources in hybrids will reduce overall emissions more quickly.

However, solid-state technology, which is far more expensive to manufacture than traditional battery systems and still requires electricity to recharge, does not appear to address all of these concerns.

As the competition to develop solid-state batteries heats up, being first to market will certainly help Toyota gain an edge in a segment where it has been slower than its competitors to roll out models.

The Japanese group claims its 20 years of experience with hybrid batteries will help it develop better electric cars. However, the large-scale rollout of electric cars is not expected to begin until the middle of this decade.

Despite the fanfare surrounding the announcement, Toyota executives themselves insist they are not just gambling on solid-state batteries and expect further technological breakthroughs to be made with liquid lithium-ion batteries.

“We don’t actually see solid-state batteries as the ultimate solution,” Toyota chief technology officer Hiroki Nakajima said.

Solid-state battery competition increases revs

Perhaps unsurprisingly, many automakers are investing in the technology in hopes of stealing a march in electric vehicles. BMW has said it will begin testing solid-state cells this year, with a development vehicle tentatively expected before 2025. However, it does not realistically expect mainstream production until the end of the decade.

Nissan has already unveiled a prototype battery plant in Japan that is working to produce a vehicle using the technology by 2028, a year behind Toyota’s latest target. The company said it expected to reduce battery costs to $75 per kilowatt-hour by 2028 and to $65/kWh later, which would make its electric cars cost the same as gasoline-powered vehicles.

Toyota’s Kaita added that the company would aim to solve the problem of high costs by simplifying the number of processes required to make battery materials.

Startups such as QuantumScape, which is backed by Bill Gates and Volkswagen, have also developed solid-state battery technology.

In 2015, vacuum maker Dyson bought Sakti3, a solid-state startup, which it believed would help it break into the automotive industry. Delays in the technology were among the reasons why in 2019 it withdrew plans to create a vehicle.

Still, the company continued to develop its battery system and is building a factory in Singapore that is expected to produce some form of non-liquid battery from 2025, suggesting it has already made a significant breakthrough.

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Showing off his ambitions

Since the appointment of a new president in April, Toyota has sought to revamp its image as an electric car laggard, under pressure from shareholders to explain how it plans to stay ahead of the global race for battery-powered vehicles.

In June, the Japanese automaker took journalists on a rare tour of its technical center near Mount Fuji, where it showcased not only its ambitions for next-generation solid-state and liquid lithium-ion batteries, but also new manufacturing methods that will make it easier and faster to produce electric vehicles.

“We’re not very good at marketing ourselves, and because we’re overly cautious, people just know we’ve been working [on a certain technology] when the product is finished, Kaita said, revealing that the company had already made early breakthroughs in solid-state battery durability issues three years ago.

Executives have typically revealed few details about its “technological breakthrough,” and Nakajima said only that the company had found a promising material for solid-state batteries.

This has led some shareholders to question Toyota’s progress, saying a lack of details on the specific “breakthrough” did not leave them convinced they could meet the target by 2027, and asking if the announcement was merely intended to calm investor concerns about its general EV approach.

Nevertheless, Toyota is set on the date. “2027 will be a challenge for us,” Nakajima said, “but it’s not that we don’t have any basis [for the date].”

Additional reporting by Eri Sugiura and Harry Dempsey in London