The Volta Foundation have recently released the 2024 edition of their annual Battery Report. These reports are well-renowned in the industry and cover the most important developments in battery research, policy and business landscape. We at Mewburn Ellis were delighted to participate in this year’s report, as Mewburn Ellis partner Callum McGuinn contributed an analysis of the battery patent landscape.
We have already commented on what the report has to say on Marine and Space Transportation and Battery Energy Storage Systems. This third instalment focuses on developments and trends in Solid-State Batteries.
Solid-state batteries differ from established lithium-ion technologies by using a ‘solid’ electrolyte as the medium for transporting lithium ions between the anode and cathode, replacing traditional liquid electrolytes. As discussed in our previous article on solid-state electrolytes, this technology promises better cell safety and stability, improved high-rate and long-term cell performance, and avoids the need for separators and difficult-to-handle organic solvents. In the fullness of time, solid-state cells also promise lower manufacturing costs.
Ceramic vs Polymer
Within the solid electrolyte space there are two main technology streams – ceramic electrolytes (also known as inorganic, including oxides and sulphides) and polymer electrolytes (solid, composition, or gel; the latter often referred to as ‘semi-solid’ electrolytes).
The relative strengths of these different electrolyte technologies are shown in the graph below, taken from page 260 of the 2024 Battery Report:
Polymer electrolytes are the more mature and currently cheaper technology. The Americas play a big role in the solid polymer electrolyte field, with North Carolina based start-up Soelect receiving backing from General Motors Ventures, and US headquartered Factorial Energy being supported by a range of European and South Korean car manufacturers. 2024 also saw Factorial Energy deliver their first cells to their automotive partner Mercedes Benz. However, Europe’s Blue Solutions are one of the most advanced polymer solid-state battery manufacturers. Unlike many researched-focused companies in this sector, Blue Solutions have been producing cells for over 13 years and have recently announced plans for a €2 billion solid-state plant in France.
Meanwhile, ceramic electrolytes, although at an earlier stage of adoption, have seen major investment and have dominated solid-state developments this year. Much of this dominance is also being driven by automakers – with Mercedes backing Ensurge, BMW and Ford investing in Solid Power, and Toyota supporting Ion Storage Systems. Indeed, Toyota’s interest in solid-state batteries is reflected by their huge portfolio of 8,274 patents granted in the 3 years up to October 2023 within this technical area.
And another Mercedes-backed company with an extensive patent portfolio, Prologium, inaugurated the world’s first giga-scale facility for ceramic solid-state cells in Taiwan in January 2024, which is due to start mass production in 2027. Ceramic electrolytes offer better ionic conductivity and thermal stability, though their brittle nature carries some limitations.
A key trend identified in the Battery Report is that semi-solid electrolytes have seen significant interest over the past year. While not a drop-in replacement for liquid electrolytes, semi-solid electrolytes have similarities in processing and handling to traditional liquid electrolyte cells, while retaining many of the safety and performance benefits of solid-state electrolytes. SES and StoreDot (who were both established in 2012) are leaders in this arena, and are backed by a range of the world’s largest automakers. Amongst them, Hyundai and Honda have recently announced that their pilot-scale solid-state battery factories are due to open in early 2025.
Looking Forward
There has been a long-standing buzz around solid-state batteries. While this technology could dominate in future, it is not yet the norm and mass production still seems to be at least a couple of years away. This can in part be attributed to how affordable traditional lithium-ion cells have become. Another factor may be the higher lithium demands of solid-state cells, and the relative scarcity and immature supply chains for the raw materials needed for ceramic electrolytes (such as lanthanum and germanium).
Nevertheless, solid-state remains a rapidly developing area (fuelled by substantial car maker investment), and we expect that innovation in ceramic and polymer electrolytes will focus on addressing these issues. In the meantime, it seems that semi-solid electrolytes will provide a gelatinous stepping stone enroute to a fully solid-state future. The progress of this technology and its industrial applications will certainly be something to look out for in next year’s Battery Report!
Read the full Battery Report 2024 series here.
