Engineering to Beat the Battery Boundaries
New materials and high-density cell technologies may lead to that elusive “battery breakthrough.”
It’s a big step from motor racing technology, hypercars and jet fighters to a baby’s mobile incubator able to withstand a 20g-impact, but that’s the usual business at Williams Advanced Engineering (WAE). Under CEO Craig Wilson, the company – technologically nimble and innovative – is playing key roles in projects that set new, broader engineering parameters rather than being guided by them.
“It’s what we do: meet and beat the challenges,” said Wilson. “We are always learning and cross-linking every program in which we are involved, to deliver the correct technical direction, often in partnerships but always with novel, individual solutions.”
One of those partnerships, led by the U.K.’s Triumph Motorcycles, sees WAE along with Integral Powertrain and WMG at University of Warwick, collaborating on a high-performance electric motorcycle that will “generate technological innovation for future motorcycles,” said Wilson in an exclusive interview with SAE International.
Designated TE-1, the electric motorbike project is supported by the U.K. government via its Innovate research and innovation organization. It is now halfway through its two-year development schedule. Led by Triumph, which is responsible for integration of all technology, it is a relatively hush-hush project in which WAE has responsibility for lightweight battery design and pack integration. Integral Powertrain’s e-Drive division is leading development of bespoke, power-dense electric motors and a silicon carbide inverter, merging both into a single motor housing.
Initially, WMG’s role was to identify partners and assist with bid writing, said Professor of Advanced Propulsion Systems David Greenwood: “Now we continue to support Triumph with project management and our technical work is focused around modeling, control and testing of the electric powertrain – to deliver an exceptional rider experience with maximized powertrain efficiency. We are also studying the wider implications associated with electric motorcycles, including manufacturing requirements, market development, regulations and charging.”
At Triumph, CEO Nick Bloor said the TE-1 project, part of its electric motorcycle strategy, is “driven by customers” who want to “reduce their environmental impact, combined with the desire for more economical transportation and changing legislation.” There’s also a focus on handling, performance and usability.
High power, energy-dense
Reducing battery size and weight are vital targets for TE-1’s success. Said Wilson: “Central to achieving this is to combine the necessary percentage of high-power cells with energy-dense cells. Increasingly, cells are improving in terms of their specific performance. But it is still the case that primarily we are looking for the tradeoff between energy density and power density.”
Williams’ in-house Multi-Chem adaptive technology has enabled reduced mass and volume yet increased target power density within motorsport. As its foundation battery supplier, WAE has played a pivotal role within Formula E. It also developed the battery pack for next year’s radical Extreme E motorsport.
Multi-Chem technology uses a bi-directional DC/DC converter to enable use of both high-energy and high-power-density battery cells in a single pack. The result is a claimed increase in useable energy density of up to 70% compared with conventional battery systems. Multi-Chem enables semi-independent sizing of energy and power cells via scalable blocks, with a compact thermal-management system delivering required cooling within tight packaging. Wilson stated that WAE has created a demonstrator battery system utilizing Multi-Chem technology to demonstrate its significant performance benefits.
“A high-power battery system, with a peak power of 550 kW (20-second pulse), providing a total stored energy of 60 kWh, has a core battery mass of 345 kg (761 lb),” he said. “Safety is a vital aspect of high-power automotive battery application and WAE uses its 223 composite manufacturing process for encasement to meet that need.”
Wilson, a former managing director of TWR Group, agreed that long-anticipated “battery breakthroughs” have been a long time coming, but has confidence that change really is afoot. “Not in the current form of chemistries,” he noted, “but it will do when we continue to get further into new materials through the use of semi-solid and solid-state applications. Commercially, they remain some way off.”
Already from its Formula E experience, Williams has realized a 30-40% mass saving, the bulk of that coming from the cells themselves, with improved performance in the past five years regarding total battery performance, Wilson said.
Electrifying motorcycles, he added, brings an additional challenge: the loss of a traditional aural signature. “Some companies have investigated fake sound, but we decided not to on this project. TE-1 is a high-, not an extreme-performance, motorcycle.”
Tackling cost is another ongoing focus of Wilson’s team. “From a battery financial viewpoint, we are looking at the possibility of making some components redundant without losing performance,” he said. “Five years ago, almost every battery program we were involved in would have a degree of thermal application, with cooling needing a radiator, hoses, glycol. Now, 50 percent of our programs have supplementary thermal management, novel air cooling and the use of materials with thermal-rejection characteristics.”
Williams’ engineers benefit from learnings derived from the cross-linking of many programs. For example, Formula E technology development is very significant at present, Wilson noted, in terms of its relevance for OEMs doing mainstream engineering.
With regard to the Triumph TE-1 project, Wilson sees its WAE-developed battery technology as having applications other than motorcycles: “One of the great strengths of our company is technology integration capability across many disciplines; F1 to fighter jets and as part of an aerospace consortium. We recently re-engineered ventilators for scalable production to support COVID-19 treatment. As a company we’re used to pushing things to the limit of complex packaging to produce whole products.”
The boundary-pushing includes WAE’s extraordinary project to provide a total 2 mW of battery power for the 2000-ps (1,973-hp) Lotus Evija all-wheel-drive hypercar. A piece of extreme electric exoticism, its thermal demands with ultra-tight battery packaging and no room for compromises.