Mass market solid state battery within reach

The next generation of battery technology, solid state batteries (SSBs), is within reach this decade, delegates heard at the virtual US Advanced Automotive Battery Conference (AABC) this week.

Solid state batteries could enable the world's first 400 Wh/kg batteries, a marked improvement on the most powerful technology today. Most nickel-manganese-cobalt batteries range from 200-300 Wh/kg.

"The jump from nickel metal hydride to lithium-ion was probably one of the most significant breakthroughs in battery history. The jump to beyond lithium-ion is going to be just as significant if not more so," said Qichao Hu, chief executive of Solid Energy Systems (SES). "This is why the industry expects this technology to allow entirely new applications like eVTOLs or to use another name, flying cars," he said.

The main difference between SSBs and conventional lithium-ion batteries is the use of a solid electrolyte that allows for higher energy density and rapid charging times, almost comparable with filling a car with fuel. They are also non-flammable and safer than conventional li-ion batteries.

Until recently, they had been theoretical. SES now claims to have created the first 400 Wh/kg battery.

"A lot of the big hurdles about lithium metal technology have been addressed," said Hu, "We're actively working with several OEMs to deliver an automotive A sample by 2022 and an automotive B sample by 2023. Finally, lithium metal batteries are moving from the lab to engineering samples, and are getting close to commercial production. If we stick to our road map then this could be in a car by 2026-27."

Challenges remain for mass market adoption

There are still hurdles to overcome in order to bring the next generation of battery technology to the market, mainly in manufacturing and scaling. "We remain optimistic that SSBs are a compelling concept with advantages in safety and energy density. The performance of SSBs will only truly be known once they are made at scale and scaling in this case is not a trivial matter," said Forrest Gittleson, a senior engineer at BMW.

He warned that large-scale manufacturing would require changes to existing battery production lines, as well as new systems in cars to deal with the expansion and contraction of solid state metal in different temperatures.

Metals demand could be impacted by SSBs by requiring different cathode and anode chemistries, but not in the next decade.

"If we look ahead 5-10 years, it's likely solid state cells will use similar cathode materials to the batteries of today," Gittleson said. This would likely mean using nickel-manganese-cobalt (NMC) or lithium-iron-phosphate (LFP) chemistry, driving demand for those metals over the coming years.

By Thomas Kavanagh