To meet the ambitious COP 26 target of all new car and van sales being for zero-emission vehicles by 2040, chemistry and materials innovation at the fundamental level of battery cells is critical to convince a global audience of the viability of electric vehicles. This must be geared towards significantly improving charging times and single-charge distances — and solid-state technology could just be the ‘holy grail’ that the market has been searching for.
Battery technology driving EV market growth
Set against the slowdown in the growth of the global car market, caused by both the COVID-19 pandemic and manufacturing disruptions that include chip shortages, the global EV market grew by a whopping 108.5% in 2021, with between 4.5 and 6.5 million EVs being sold. EV sales now make up around 9% of all passenger car sales, with forecasts indicating that this will increase to just over 60% by 2035 (50% from fully electric vehicles, 10% from plug-in hybrids).
Such positive forecasts are largely driven by battery innovation and affordability. Lithium-based EV battery packs are predicted to maintain their market dominance in the short term, with a new EU regulatory framework for batteries (alongside new recycling regulations) on the horizon. Its aim is to pave the way for a circular and climate-neutral economy in sustainable batteries. In terms of cost, lithium-ion batteries are estimated to be around 30 times cheaper today relative to the early 1990s, with the relative cost of a comparative petrol or diesel car expected to reach parity by the mid-2020s (excluding running and maintenance costs, which are strongly in favour of EVs).
The solid-state revolution
While lithium-ion (li-ion) batteries have reached a dominant share of the current battery market through incremental improvements to the fundamental aspects of the cell (including the anode, electrode, electrolyte, thermal management systems and discharge and charging cycles), many industry experts acknowledge that they have significant flaws. The widely used electrolyte is ethylene carbonate, which is flammable and releases toxic gases if combusted. There are also technical barriers that prevent further engineering optimisation — including safety, cost, energy density (both volumetric and weight), charge and discharge rates and battery cell lifetime — alongside the issue of sustainably sourcing the required raw materials and environmental concerns with mining processes in underdeveloped countries.
The most viable alternative — solid-state batteries — have attracted significant attention over the last decade by promising improved safety, energy density and electric vehicle range. In place of the flammable liquid electrolyte, solid-state batteries include a non-liquid electrolyte which takes one of three forms — inorganic (ISE), solid polymer (SPE) or composite polymer (CPE). The global solid-state battery market includes large players like Toyota, Samsung SDI and Quantumscape alongside start-ups that specialise in improving specific aspects of the cell (such as electrodes, electrolytes and software management).
The ‘holy grail’ of battery technology
Innovation is highly competitive, with large volumes of patent applications being filed globally in the race to develop the next generation of ‘super batteries’ for the EV world — those that can charge quickly, deliver sufficient power over a long period of time and are safe and ‘green’ (using sustainably sourced materials, environmentally friendly production processes and with the ability to be recycled conveniently).
In pursuit of this, patent filings are increasing across all aspects of solid-state cells and batteries including dendrite-suppressing systems; interfacial compatibility between the solid electrolyte and the cathode and anode; and configurations to supress the internal resistance of the cathode and anode active materials.
Patent literature is a valuable resource of ‘state of the art’ battery innovations. Being aware of the latest developments is important to prompt, validate or redirect R&D efforts, while ensuring that new lines of development and commercial offerings don’t infringe existing rights. A patent that protects a significant development in the emerging solid-state sector will be incredibly valuable, as major EV and electronics manufacturers look to partner with any developer of a ‘solid-state ready’ cell.
Can we meet the COP 26 target?
Solid state battery technology ultimately does have the potential to provide an effective replacement for conventional fossil fuels in vehicles and therefore will play a significant role in meeting the COP 26 target. The technology is developing rapidly in many different directions, from the fundamental materials of the cell to innovative systems such as Gogoro’s scooter battery swapping capability.
Yet the ‘holy grail’ of batteries is unlikely to be achieved by just one company — based on previous patent filing activity and trends in other technology areas, it’s more likely that the ‘breakthrough’ in solid-state technology will be attained via a collective effort of incremental improvements across the industry.
It’s important to note that other technical, social and economic factors will play a role in advancing the global uptake of EVs. These include vehicle costs and national charging infrastructures, alongside the increasing cost of electricity. The battery tech scene looks encouraging from the perspective of patent filing activity and there is every chance we will continue to see innovation and collaboration across the broader EV landscape as we all work towards a greener future.
Martin will be at the co-located Advanced Materials Show, Battery Cells & Systems Expo and Vehicle Electrification Expo at the NEC, Birmingham (UK) between 29 and 30 June. Talk to him at Stand 525 in Hall 18, or connect with him on LinkedIn to arrange a meeting ahead of time.
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