17 response mechanism used by transmission-system operators to stabilise frequencies against sudden changes in electricity supply or demand, principally to keep grids stable. Stress and power density However, optimisation of EV charging raises questions over the increased degradation and stress that batteries suffer from repeated charging and discharging. “There is no ‘yes’ or ‘no’ answer to this question; it only depends on what you’re doing with the battery,” says Fischer. “Obviously, if you run it from 0% to 100% SoC and back over and over again each day, you’ll induce lithium dendrite build-ups and reduce your pack’s lifespan quite a bit.” “With our frequency control reserve, we can control for very small SoC swings, even keeping packs in the sweet spot of 40-60%, which can have a positive effect on battery lifespans. But then most of your electronic components could be working 24/7 and suffering lifespan drops of their own because you’re managing the SoC too persistently. We’re accounting for that when researching new power electronics, ECUs and so on.” For Fischer, the path forward certainly includes shifting r&d from focusing only on battery energy density and rerouting it towards power density, such that gradual improvements in charging infrastructure will make recharging passenger EVs as simple and timeefficient as refilling at petrol stations. Further enablers for a smarter energy future will include the ability to make batteries from sustainable materials, improved thermal management strategies for mitigating cell temperature increases during charging, and advancements in battery engineering. Here, Fischer cites cell-to-pack architectures as an efficient means of maximising energy density, but he cautions that recycling such packs could be extremely difficult without a straightforward disassembly method. Zero-impact, infinite possibility Fischer believes big challenges remain before battery recycling becomes a reality. Material selection is among the largest and makes for a significant source of trade-off. The more that rare materials such as nickel or manganese are used in cells, the more of a business case there is to recover and reuse such materials. But their rare nature also drives the creation of batteries from more abundant, low-value materials, for which recycling and circularity would be far less easy to achieve via a profit motive. “Batteries with only cheap and abundant materials – for example, sodium-based ones – could be a great path towards more sustainable and affordable packs one day, but regulations would be needed to make recycling of them mandatory and not lead to scrap hills of depleted packs,” he says. Honda R&D Europe has recently extended its energy testbed with a 225 kW electrolyser and extensive hydrogen-storage infrastructure. “We think hydrogen will play a huge role in future energy and mobility, even if hydrogen isn’t always necessary for passenger cars as batteries can satisfy most of their range requirements. There are so many vehicles and industries where hydrogen is important for decarbonisation that we shouldn’t view electric and hydrogen systems as separate. It is more correct to take a holistic view, optimising total energy efficiency and storage with whatever is the smartest solution,” Fischer says. “For instance, on really sunny days, our PV cells will generate 750 kW, and the energy from that can’t all be stored in batteries alone. It makes much more sense to store it as hydrogen, which can be used to refuel FCEVs [fuel-cell EVs], H2 engine-powered vehicles or combined heat-and-power systems. And while those might be three different ways of applying hydrogen, again, we don’t view them too separately here at Honda when it comes to our research. “There’s a reason we seat our virtualsimulation engineers next to our benchtesting engineers. Each can directly learn ways to improve their own software and tools from the other so long as they communicate well – much as is the case with our different hydrogen research teams, and of both hydrogen and battery EV developers.” E-Mobility Engineering | March/April 2024 Michael Fischer Michael Fischer was born and raised near Darmstadt in Hesse, Germany. After graduating secondary school in 1999, he performed one year of civil service before beginning a degree programme at the Technical University of Darmstadt in 2000. He achieved a master’s diploma in engineering in 2006, and wrote his thesis (as part of a collaboration between Honda and TU Darmstadt) on how advanced NOx aftertreatment techniques could be applied to diesel passenger cars to effectively reduce harmful emissions. That year, Fischer started working as a project leader (powertrain) at Honda R&D Europe, becoming section leader for powertrain technology in 2011, and achieving his doctorate in 2013. Over the subsequent 10 years, he advanced through a number of managing roles across automotive engineering, materials research and digital solutions, directing growing teams of specialist researchers at the Honda R&D Europe facility in Hesse. In April 2021, Fischer became deputy general manager for Honda R&D Europe’s Energy & Automobile division, a position he continues to hold to this day.
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