Innovation in solid-state batteries for EVs and electronics is being spearheaded by Japanese giants including Toyota and TDK, according to a new report.

Delivered by intellectual property specialist Appleyard Lees, Inside Green Innovation: Progress Report 2022 explored activity across several different technology sectors, using patent filings to gauge interest and potential growth. The report found that patent filings in Li-ion battery technology have levelled off, while solid-state innovation is rising significantly, largely driven by Japanese car and electronics manufacturers, including Toyota, Honda and TDK. According to Appleyard Lees, the first Toyota vehicle to feature a solid-state battery is scheduled to launch in 2025.

“Annual priority filings in solid-state battery technology went from 75 in 2015 to more than 400 in five years, with Japan dominating the field,” said Paul Beynon, patent attorney & Appleyard Lees senior associate. “That said, there’s life in Li-ion yet, with battery makers shifting their attention to alternative materials.

“Equally, there are recent moves to address the recycling challenges of both solid-state and Li-ion batteries, with new patent applications arising from California.”

Solid-state batteries are potentially safer and more energy dense than existing lithium-based technology, though costs are currently prohibitive for many use cases and Li-ion still proliferates in the EV and electronics markets. One significant innovation trend highlighted by patent activity in Li-ion technology is the recent shift to using lithium iron phosphate (LFP) rather than nickel manganese cobalt (NMC) due to cost and safety issues.

According to the report, patent filings in LFP went up by almost 40 per cent between 2019 and 2020, with South Korea’s LG Energy Solution the most active player. Germany’s Bosch has led the charge in Li-ion patent filings among businesses globally since 2020, likely driven by its joint venture with Volkswagen to expand electric vehicle battery production in Europe. But as the EV market expands in Europe and around the world, end-of-life solutions for the proliferation of batteries will become a key priority.

“Though the recycling rate for Li-ion batteries is currently less than five per cent, innovation activity at the University of California has led to patent applications for recycling Li-ion battery cathodes and for recycling all solid-state batteries,” explained Tom Gregory, patent attorney at Appleyard Lees. “Progress in this area could be vital to ensure the future sustainability of these battery technologies.”