There are few areas in the world of clean energy – as the International Energy Agency’s latest global EV outlook report states – as dynamic as the electric vehicle (EV) market.
Sales of EVs year-on-year doubled in 2021 to a “new record” of 6.6 million, bringing the total on the world’s roads to 16.5 million, versus 10 million in 2020.
This drive towards EVs is pushing the demand for an affordable, clean energy power source – and the leading contenders in this are Li-ion and solid-state batteries.
But while new patent filings in li-ion technology have plateaued, activity in solid-state batteries is gathering pace – driven mainly by Japanese car and consumer electronics companies. We highlighted the exponential growth in solid-state battery patent applications in last year’s Inside Green Innovation: Progress Report 2021; though li-ion technology isn’t going away, as this year’s report shows.
A Research and Markets report from July 2022 forecasts a CAGR for solid-state batteries of 34.7% (2021-27), increasing from USD 851.77 million to USD 5,076.99 million. Meanwhile, Research and Markets predicts the global Li-ion market will grow from USD 41.93 billion in 2021 to USD 48.86billion in 2022 at a compound annual growth rate (CAGR) of 16.5%, with the market expected to reach USD 85.72 billion in 2026 at a CAGR of 15.1%.
With the continued growth in this area, this part of the report takes another look at the patent data to identify more recent trends.
Global patent activity
Figure 1 shows the breakdown in jurisdictions of li-ion filings. The graph below includes all Chinese filings (including those that did not result in a PCT filing). However, we have included them in this graph to show the comparison with the data in last years’ report.
Figure 1: Ten-year filing activity, by jurisdiction (including China) - li-ion technology
The results indicate that China continues to lead the way in filings, with further approximately 3,000 filings in the past year alone. The other territories increased at only a relatively modest rate, in comparison.
Figure 2 below shows the number of priority filings, by year, when the Chinese results are removed from the dataset:
Figure 2: Twenty-year trend: priority filings (excluding China) – li-ion technology
These results show a plateauing of li-ion filings over recent years, which could be because innovation in this field – consistently high since 2011 – is difficult to maintain.
Notable companies
The notable companies working in this field are set out in figure 3.
German firm Robert Bosch continues to lead the field in the number of filings with a recent uptick in 2020, reversing the downward trend from 2017 to 2019. This may be due to a recent agreement between Robert Bosch and Volkswagen to establish a joint venture by the end of 2022, with the aim of expanding the production of lithium-ion batteries for electric vehicles in Europe. BMW also had a significant increase in filings in 2020.
JX Nippon Mining and Metals Corp and Toyota also have a strong number of filings, indicating the continued push for Japanese firms in this field.
Figure 3: Filing activity 2011-2020: Top companies filing lithium-ion priority patent applications
Li-ion materials
We also explored the two main types of li-ion battery types currently being developed: nickel manganese cobalt (NMC) and lithium iron phosphate (LFP).
NMC technology has been the front runner for powering electric vehicles to date due to its higher energy capacity. However, a by-product of NMC batteries is oxygen, which requires additional safety measures when in use. NMC batteries are more expensive to produce and the supply of cobalt is limited. Therefore, many companies are looking to LFP technology as a cheaper alternative.
Figure 4 below shows that, even though LFP filings peaked in 2012 (similar to the trend in li-ion filings overall), filings in 2020 increased by approximately 50% from 2019, indicating a recent shift towards LFP.
Figure 4: Twenty-year trend: priority filings – lithium iron phosphate (LFP)
Figure 5 shows the equivalent number of NMC filings, which is lower than the overall number of LFP filings. However, since 2017, the number of filings has increased, indicating a recent batch of innovation in this field.
Figure 5: Twenty-year trend: priority filings – nickel manganese cobalt (NMC) applications
The data in Figure 6 indicates that South Korean manufacturer, LG Energy Solution – the most prolific LFP filer in recent years – is significantly more active than other companies in its transition to LFP technology.
The data indicates that many companies are looking at cheaper and more abundant alternatives to traditional NMC li-ion batteries; it will be interesting to see what the next generation of EVs use as the li-ion power source.
Figure 6: Top 5 companies filing Nickel Manganese Cobalt (NMC) applications
Solid-state batteries
Figure 7 shows that the number of patent filings relating to solid-state batteries continues to rise at a significant rate.
Figure 7: Twenty-year trend: priority filings – solid-state batteries
Even with the inclusion of all Chinese filings as shown in figure 8, Japan is still leading the way with the number of filings in this area – extremely rare given the number of Chinese patent applications in most fields over the past few years.
Figure 8: Ten-year filing activity, by jurisdiction (including al Chinese applications) - li-ion technology
When excluding China-only applications, Japan’s significant lead in filings is even more pronounced, as indicated in figure 9.
Figure 9: Ten-year filing activity, by jurisdiction (excluding China-only applications) - Li-ion technology
Japanese car manufacturers are the most prolific filers, namely Toyota, Hyundai and Honda. Other large Japanese electronics manufacturers, Murata and TDK, are also prolific filers in this field. Indeed, TDK has recently announced a USD 5 billion investment in EV battery production over the next three years, with an intention to use solid-state batteries in consumer electronics.
Toyota is still the largest filer in this area by a significant distance and has recently announced that its first vehicle to use solid-state batteries will go on sale by 2025. Interestingly, reports suggest that Toyota’s first solid-state battery vehicle will be a hybrid (potentially the Prius), rather than a full EV, to keep costs down.
The patent data shows a year-on-year increase in filings and it will be interesting to see how other car makers will respond to the significant investment made by Japanese car manufacturers in solid-state batteries.
Figure 10: Ten-year activity: Top companies filing solid-state battery priority patent applications
Recycling
A common issue with both li-ion and solid-state batteries is the difficulty with recycling. In last year’s report we highlighted that less than 5% of li-ion batteries are currently recycled. In a conventional battery recycling plant, battery parts are ground into a powder, and then either melted (pyrometallurgy) or dissolved in acid (hydrometallurgy).
However, li-ion batteries are made up of lots of different parts that could explode if not disassembled correctly. And even when li batteries are broken down this way the products aren't easy to reuse.
The University of California is researching this area, with two patent applications –WO2022076904A1 (Recycling and regeneration of lithium-ion battery cathodes) and WO2021119295A1 (Recycling all solid-state battery technology) aiming to address this issue from the outset.
WO2022076904A1 sets out a method for the regeneration of spent cathode material of lithium-ion batteries while WO2021119295A1 outlines a method of recycling all solid-state batteries.
Innovation in these areas could be a vital component in ensuring the sustainability of li-ion and solid-state batteries.
Tom Gregory European Patent Attorney