Having a battery that is roughly half the size and weight opens the door for a greater variety of EVs including sports cars which benefit in terms of performance and handling from being as light as possible.Courtesy of manufacturer
Solid-state batteries are touted as the next big leap for electric vehicles. Compared to their “liquid” counterparts, they’re safer, more energy-dense and less affected by temperature extremes. This all adds up to a battery that is smaller, lighter, has more range and can charge faster. It may also one day bring down the price of electric cars. Batteries in EVs weigh around 450 kilograms and cost about $20,000 to manufacture, making them a significant part of the over all price of the car. Automakers are hopeful these new batteries will be produced at a lower cost.
Car companies including Nissan and Honda are working fastidiously to put them into mass production, setting targets to produce a vehicle using these next-generation batteries before the end of the decade.
Volkswagen and BMW are also in the arms race to develop them. And Toyota recently announced a “breakthrough” with technology that puts them on track to have commercially ready solid-state batteries by 2028.
Having a battery that is roughly half the size and weight opens the door for a greater variety of EVs including sports cars which benefit in terms of performance and handling from being as light as possible. But every EV will benefit from lighter and smaller batteries, including the average family crossover.
Toyota’s proposed solid-state battery-powered EV will have up to 1,200 kilometres of range and take 10 minutes to charge from 10-80 per cent. It sounds optimistic at this stage, but if those claims turn out to be real, it would truly be the breakthrough the company says it is.
Solid-state batteries aren’t a new technology and have been used for years in smaller applications like RFID tags and pacemakers. Scaling them to the size required for a vehicle has proved more difficult.
“Ions don’t flow as freely in a solid so the materials must be stamped together in a precise manner for a proper interface,” says Hayato Mori, Honda Canada’s assistant vice-president of business development. “This stamping sounds simple but is challenging to conduct. Too much pressure may damage the microstructure of the materials, lower the battery performance or damage other elements of the battery. Too little and the ions won’t conduct fully.”
Honda is producing 0.8-kilowatt solid-state battery cells, about the size of a chocolate bar, at its pilot production lab in Tochigi, Japan. The company uses a roll press to sandwich the electrodes and electrolyte together. “One of the ways Honda has overcome the consistency of the electrolyte is to roll it out like a strudel layer,” says Mori. Honda is experimenting with the speed of the rollers. Right now they spin quite slowly, but will be sped up over time to a speed suitable for mass production.
Both types of lithium-ion batteries, solid and liquid, work similarly, but solid-state batteries use a solid electrolyte instead of a liquid. Each battery contains a positive side (cathode) and a negative side (anode), with the electrolyte in the middle. Lithium ions flow through the electrolyte from one side to the other creating a current that drives the electric motors in a car.
Lithium ions flow more easily through a liquid than a solid, but liquid electrolytes don’t handle temperature extremes well. That’s why traditional lithium-ion batteries don’t operate efficiently when it’s too cold or too hot. Liquid electrolytes are also highly flammable and damaged cells risk going into thermal runaway and catching on fire. Lastly, a solid-state battery doesn’t require a separator between the anode and cathode and can be made more compact.
Finding the perfect cocktail of materials for the solid electrolyte is a key challenge, the other is mass-producing the batteries.
Volkswagen-owned PowerCo and QuantumScape just signed a deal to mass-produce solid-state batteries using QuantumScape’s technology. PowerCo was founded by Volkswagen in 2022 and they are a global battery cell manufacturer currently building a massive plant in St. Thomas, Ont. The German automaker also invested in U.S. startup QuantumScape to help them develop solid-state batteries.
A previous Reuters article reported that the two companies were “dogged by delays” and that Volkswagen was also in talks with Blue Solutions, a French company that makes solid-state batteries for Daimler electric buses, which is only telling of the hurdles automakers are facing to be first out of the gate with a commercial solid-state battery.
Mori says that “producing solid-state batteries in volume is a challenge.” He adds: “This past spring, construction of a new facility was completed to house a demonstration line for manufacturing solid-state batteries. The proof-of-concept line is expected to begin operating this autumn to help further our research and development.”
Toyota entered into an agreement to mass-produce solid-state batteries with Idemitsu Kosan Co., Ltd., a Japanese petroleum company. “The chief drawback of solid-state technology is battery durability,” says Scott MacKenzie, director of corporate and external affairs at Toyota Canada Inc. “Idemitsu has worked on solving this issue with Toyota since 2013.”
Idemitsu discovered the advantages of using sulphur components, a byproduct of manufacturing petroleum products, to create a sulfide-based solid electrolyte. The companies say they are confident it’s the most promising solution for solid-state batteries.
“Through a decade of trial and error, the companies combined their technologies to develop a flexible, highly adhesive and crack-resistant solid electrolyte material,” says MacKenzie “Pairing this new electrolyte with the Toyota Group’s cathode and anode materials and battery technologies has put the partnership on a path toward achieving both performance and durability.”
Nissan is developing its battery at the Nissan Research Centre in Japan and says that some of the challenges in production have been developing a structure that can handle cell expansion and contraction, improving contact between the solid electrode and solid electrolyte, maintaining long-term battery performance and ensuring safety. A spokesperson for the company says that despite this they are “on track to offer a production EV with an all-solid-state battery within fiscal year 2028.”
Another less talked about benefit of the solid-state battery is cost. A solid electrolyte can effectively operate at much higher and lower temperatures than a liquid electrolyte. It allows for a broader range of potentially cheaper materials and possibly even less metals to produce, but the “recipes” for these batteries are still closely guarded secrets.
Nissan Canada says solid-state batteries can be produced “at a lower cost than conventional lithium-ion batteries.” However, Mori says it will be more expensive initially until they figure out how to mass produce them consistently.
As close as it seems we are to this Holy Grail for electric vehicles, there are still many challenges ahead and few firm dates. Toyota is aiming to commercialize its solid-state battery by 2027-28. They say mass production will come after, although it is unclear what that means. Nissan, however, seems the most confident, saying they’ll have the battery ready in 2028 with an EV to go along with it. The Nissan Leaf was one of the first mass-produced EVs on the market, maybe the company feels it has something to prove.