E-Mobility Engineering 019 | In conversation: Stephen Lambert l WAE EVR l Battery case materials focus l Quality control insight l Clipper Automotive Clipper Cab digest l Optimising battery chemistries insight l Powertrain testing focus

May/June 2023 | E-Mobility Engineering 17 saw it as the battery technology of the future, as well as a safe direction for cell developments to go in. “It didn’t have the best energy density, but it had good power density, and certainly for high-performance applications it was seen as a really interesting technology,” Lambert recounts. “Certainly over the past 5 years, NMC has taken hold in EVs – most EVs on the road have either NMC or NCA cells in their packs – but what’s really interesting is how we’re seeing LFP come back around and become much more dominant, especially in lower- cost markets, as well as in heavy-duty and high-performance applications where you need a higher power density and charging rate without making your EV less safe.” The exact chemistry used in the McLarenMP4-30 remains a secret, having been a very particular chemistry specified to an exact set of requirements for the racecar’s powertrain. Its development startedwith chemical fundamentals and endedwith homologation testing of the fully assembled pack. Lambert left McLaren Racing in mid- 2015 but then joined McLaren Applied as head of electrification in November 2016, and found himself once again working in the McLaren Technology Centre. “I was offered the chance to spearhead McLaren Applied’s strategy for a scalable electrification business,” he says. “It was transitioning from being a consultancy service into a product maker, and since I already lived near them, in Woking [southern England] – running Vayon Energy Storage – and because I still knew a lot of people in McLaren, they asked me to join.” Going in, he had imagined he would be remaking McLaren Applied into a battery company, particularly given its ongoing work in Formula One and Formula E on electrified drivetrains, and his own lengthy experience in batteries. However, he soon realised the company actually had a bigger edge (relative to the rest of the industry) in power electronics and functional safety- critical systems, and that this would be invaluable for what e-mobility was going to need in the future. “We saw efficiency, particularly through 800 V automotive architectures and silicon carbide [SiC], being a major driver in the future,” he says. “In that light, a lot of what McLaren Applied was accomplishing with inverters for Formula One and Formula E was directly in line for where the automotive industry was going to go.” This was followed by concept development, prototype iteration and some further market research to confirm that power electronics was the right direction to go in. That resulted in the IPG5, the company’s first inverter aimed at the high-end EV industry of the 2020s and beyond. recovery systems in its Honda Formula One powertrains raced from 2015 – and some battery manufacturing and engineering companies. From batteries to inverters At Lotus, Lambert worked on demonstrator vehicles including a hybrid Lotus Evora and the fully electric Rolls-Royce 102EX. It was through such projects that he built up experience in battery design and engineering. At the time, there were no reliable supply chains for EV or HEV batteries, so he moved to Goodwolfe Energy to build battery packs first-hand. “The opportunity then came up to help develop the battery system in the MP4-30, McLaren’s 2015 Honda- powered Formula One car,” he says. “My experiences at Lotus and Goodwolfe were key here.” Much of the technology he worked with from the late 2000s to the early 2010s was oriented around lithium iron phosphate (LFP). Companies such as A123 Systems were focused on LFP, and In conversation | Stephen Lambert During his doctorate in 2010, Lambert developed a hybridised version of a sportscar fromWestfield Sportscars (pictured)