Patenting trends in battery technology are a sign of both an increasingly mature market for lithium ion batteries and growth in research into alternative lithium-based solid-state batteries. This comes at a time of increasing uptake for electric vehicles (EVs), boosted by regulatory targets and Government subsidies, and lower costs because of technological advancements.
Patenting trends in EV battery technology
There has been a sustained increase in battery technology innovations in recent years. This comes as governments emphasise the decarbonisation of transport in line with their climate change commitments For example, the announcement in November 2020 that the UK will end the sale of new petrol and diesel cars and vans by 2030 was swiftly followed by another commitment in March 2021 to invest over £30million to boost battery technology research, the EV supply chain, and hydrogen vehicles. This included proposals to build a lithium extraction plant in Cornwall for use in EV batteries.
From a legal perspective, obtaining patent protection for an inventive product (or process) means that the patent owner obtains an exclusive right to stop others from manufacturing, selling or importing the product covered by the patent, in exchange for disclosing details of how the invention works. This monopoly may be particularly broad in new areas of technology and last for up to twenty years. It can be asserted against a competing product regardless of whether that has copied the patented technology or invented it completely independently. A patent - particularly in an area of rapidly developing technology - can therefore be an extremely valuable asset, which can be exploited by the patent owner either directly or by licences to third parties.
Interpreting patenting trends is not an exact science. However, since a patent application is typically published 18 months after filing and the process of obtaining a patent requires time and investment, they are usually a precursor to commercial exploitation and can often be considered as a good indication of trends in technological developments.
The European Patent Office (EPO) recently reported a growth rate of international patent families related to electricity storage of 14% between 2005 and 2018, compared with just 3.5% on average for all technology areas. Of the patents related to energy storage, a striking 88% related to battery technology. Furthermore, since 2011 the annual number of patents filed concerning EVs has exceeded those focusing on consumer electronics.
Geographically, the applicants filing international patent applications relating to battery technology are primarily based in Asia with Samsung, Panasonic, LG Electronics, Toyota, Hitachi, Sony, NEC, Nissan and Toshiba comprising 9 of the top 10 companies patenting battery technologies between 2000 and 2018. The only other spot in the top 10 was occupied by Bosch of Germany, which filed the majority of patents by a European company in this field.
The dominant battery technology in EVs still uses lithium-ions cells, in which positively charged lithium ions are carried by a liquid electrolyte from the anode to the cathode through a separator. Lithium-ion batteries remain the most actively researched area of technology, with 8,300 patents reportedly filed outside of China in 2019 alone.
Much of this research has focussed on identifying alternative materials for cathodes in Li-ion cells in order to improve their energy density, which in turn extends EV battery life. The most promising materials to date have predominantly been cobalt or nickel based. Specifically, these cathodes utilise nickel manganese cobalt oxide, also known as NMC; or nickel cobalt aluminium oxide, NCA. These technologies have been successfully commercialised, with Panasonic introducing lithium-ion cells with NCA cathode chemistry for Tesla’s Model 3 in 2017. This reportedly offered the highest energy density battery technology in EVs to date at over 700 watt-hour per litre.
Cobalt is, however, expensive and its use is increasingly controversial due to a problematic supply chain (60% of cobalt deposits are from the Democratic Republic of Congo). This has driven interest in further innovation in cathode chemistry. In July 2020, Tesla announced its plans to eliminate the use of cobalt in the batteries used in its EVs, and instead focus on lithium-iron technologies such as lithium iron phosphate (LFP). Although fewer patent applications concerning LFP have been filed than for NMC or NCA cathode technologies, interest in this area has risen significantly in recent years. This has the potential to accelerate further growth in the EV market, as these developments have the scope to reduce the costs associated with EV batteries.
Lithium-based solid-state batteries
In parallel with the trends described above, Lithium-based solid-state batteries are emerging as a promising alternative to lithium-ion batteries. Rather than using liquid electrolytes, these use solid-state electrolytes and are anticipated to enable the use of smaller batteries with an even higher energy density, longer lifespan, and better safety profile.
The EPO has reported an increase in patenting activity of solid-state battery technologies by an average of 25% per year since 2010. Although this technology has not yet been commercialised, a number of companies have recently announced their intentions to launch EVs utilising solid-state batteries in the next five years.
Particular interest has been shown in US-based QuantumScape, who has recently presented data demonstrating the potential for its lithium-based multilayer cell batteries with the ability to cycle close to 800 times with approximately 90% capacity retention. It has filed numerous patents related to this technology with innovations relating to increased energy density, faster charging, and reduced degradation compared to lithium-ion batteries. QuantumScape has received significant interest from investors as a result of its apparently market-leading position in this field.
It's not yet clear, however, who will be responsible for bringing the first commercially available EV powered by solid-state battery technology to market. Announcements have been made by Nio, a Chinese company specialising in EVs, of plans to launch a model incorporating this technology by the end of 2022. Similarly, Toyota, in partnership with Panasonic, has announced plans to introduce a mass-produced EV with a solid state battery before 2025. Nissan has reportedly also expressed an intention to utilise solid state batteries in an EV by 2028, though it is not clear if this model will be widely available.
Clearly there is significant interest in the potential of this technology and it will be interesting to see which companies, if any, succeed in developing a model suitable for mass production, and how long it takes for EVs utilising solid-state batteries to become affordable enough to be accessible to the mass market.
Research into a range of alternative technologies has also accelerated in recent years. For example, there is potential for hydrogen fuel-cell cars, often described as fuel cell electric vehicles (FCEVs) to become a real competitor to battery powered EVs in the medium term. As FCEVs are locally emission free, they have been hailed as key to tackling climate change. With interest in this space increasing, the pace of innovation looks set to continue.
For the time being, lithium-ion batteries continue to dominate EVs, which is reflected in the sustained numbers of patents being filed for this technology. However, the pace of research into solid-state battery technologies is also accelerating and can now be seen as a promising option to decarbonise transport without some of the drawbacks associated with "traditional" lithium-ion batteries. It will be interesting to see which technology makes the biggest impact commercially, and how this supports wider aims to decarbonise transport in the future.
As battery technology matures, the market will inevitably become more crowded as companies seek to commercialise these technologies. Increased competition is likely to drive down prices further, which is good news for consumers. It is also likely that we will see an increase in disputes concerning the patents associated with these innovations. This may be by companies asserting their patents against infringing EVs, competitors seeking to invalidate patent rights threatening their products, or else other parties needing to obtain judicial relief to clarify the position of their battery technology with respect to patents of concern.