Solid-state batteries have long been touted by industry experts as a potential “game-changer” to enable mass adoption of Electric Vehicles (EVs).
It’s supposed to be the final answer to the current EV battery concerns around charging time, mileage/ range and the risk of fire.
Many major automakers – with the exception of Tesla have disclosed development efforts or partnerships in this field. Names include – Toyota, Nissan, Honda, Hyundai, Ford, BMW, Volkswagen, Mercedes-Benz.
What are solid-state batteries, and how are they different from the currently used Li-ion?
A solid-state battery is made up of a cathode, anode, and solid electrolyte. It is different from lithium-ion batteries that use liquid electrolyte.
The current Li-ion batteries risk damage, such as swelling or leakage, as they use liquid electrolytes. They are also more prone to catching fire.
A solid-state battery with solid electrolyte negates these worries and provides more stability with a solid structure. It also increases the device’s safety, even if the battery is damaged.
Besides, Solid-state batteries can hold more energy than the li-ion batteries – hence also the higher range.
So why it’s already not in usage? What are the bottlenecks?
Solid-state batteries have been used in small electronic devices such as pacemakers and smart watches.
Mass-market production of the batteries for EVs has been slower to develop; producing them in large volumes is costly and difficult.
Problems include the extreme sensitivity of such batteries to moisture and oxygen, as well as the mechanical pressure needed to hold them together to prevent the formation of dendrites, the metal filaments that can cause short circuits.
Hence, they are expensive to fabricate and prone to cracking.
What is Toyota claiming now?
According to Toyota, the biggest difficulty for mass production is the assembly process, in which the layers of cathode-anode cells need to be stacked quickly and with high precision, without damaging the materials.
A Toyota engineer has said: “In terms of the stacking speed, we are almost there. We are going to roll out bigger volumes and check the quality.”
Due to the above development, Toyota expects that by 2027-28, it would be able to manufacture solid-state batteries at the same pace as existing batteries for electric vehicles.
Toyota parallely also make many other exciting claims –
- Cost and size of batteries would become halve making them comparable with the li-ion batteries
- Range would double to 1,200 km
- Charging time will be 10 minutes or less.
- By comparison, the Tesla Supercharger network, the largest of its kind, offers the equivalent of 321 km of charge in 15 minutes.
(Recently, Toyota agreed to work with Idemitsu, a major Japanese oil company, on technology for mass production of solid-state batteries. Idemitsu has been researching basic technologies for all-solid-state batteries since 2001. Toyota started in 2006).