As reported in our previous article on the EPO’s Patent Index, patent filings in the field of battery technology have surged in recent years, with year-on-year increases of over 20% being the norm.
These filings cover improvements in all aspects of the technology, ranging from the development of new materials for individual battery components to novel battery architectures; processes for assembling individual batteries into battery packs; and the design of suitable battery management systems.
Here, I delve into an emerging technology in the field of anode materials for Li-ion batteries.
The opportunities and challenges of silicon anode materials
Currently, the dominant material in anode production is graphite, which is valued for its stability and good cycling performance, in addition to benefiting from well-developed production processes. However, there is a strong interest in exploring alternatives to graphite, with the aim of increasing the energy density of batteries, as well as diversifying the supply chain for anode materials.
One such alternative is silicon, which has a capacity per unit weight that is ten times that of graphite. Additionally, the ubiquity of silicon (as the second most common element in the Earth’s crust) makes it attractive from both a practical and strategic perspective.
The main obstacle to widespread adoption of silicon as an anode material is currently considered to be the significant levels of volume change that it exhibits during the insertion and removal of lithium ions. Expansion of up to 400% can occur during charging, which may result in mechanical degradation during battery cycling, placing a limit on the ultimate lifespan of the battery.
Different strategies are being pursued to mitigate this problem, each of which achieves a different balance between the requirements for energy density, reliability, and cost-effectiveness. These include the creation of composite materials in which silicon is present in the pores of a porous carbon framework; the design of mechanical systems to constrain the swelling of silicon during charging; and the mechanical processing of metallurgical-grade silicon to achieve defined particle size distributions.
A rapidly expanding battery patent landscape
The increasing importance of silicon as an anode material is noted in the recently-released Annual Battery Report from the Volta Foundation, which highlights a dramatic rise in patent publications in this technical field over the past few years.
We can expect more developments in this field in the near future, with the ultimate aim being batteries with higher energy density or smaller and lighter batteries (a goal that is particularly relevant to Electric Vehicles). This remains an area to watch.
Protecting IP in battery technology
Innovators in this sphere will, of course, be mindful of the need to protect the IP generated from their investment in developing new anode materials.
One form of IP that is often overlooked when developing an IP strategy is the protection of trade secrets. For example, when a new anode material has been invented, it may be tempting to move on to fresh challenges once the patent application is on file. However, it is worth spending some time considering whether there are outcomes of the development process that should be protected as trade secrets. These could include new discoveries or scientific theories generated in the course of the project; experimental strategies that initially seemed promising, but were ultimately found not to work; as well as non-technical information relating to suppliers and / or costs.
Once these items have been identified, it is important to record them as trade secrets, and to set up systems to maintain the secrecy of the information. We can advise on all aspects of this process.
