The electric vehicle (EV) revolution is not just about sleek designs and zero-emission promises—it’s powered by decades of behind-the-scenes innovation in batteries and power electronics. In a recent interview, engineers John Samuel and Pete James shared their insights into the technological breakthroughs that have made modern EVs possible.
The Battery Bottleneck
One of the earliest and most persistent challenges in EV development has been energy storage. As John Samuel explained, “There’s something like a 60 to one differential between petrol and battery power.” While electric propulsion is more efficient than internal combustion, the sheer weight and volume of batteries needed to match the energy density of petrol posed a major hurdle.
“In the early days, we were working with rather limited lead-acid batteries,” Samuel recalled. “A petrol tank might weigh 150 kilograms. To match that, you’d need over a tonne of batteries.”
This limitation shaped the design of early EVs, pushing engineers to focus on lightweight materials, aerodynamic efficiency, and compact city cars. But the real game-changer came with the advent of lithium-ion batteries.
The Lithium-Ion Leap
“Lithium-ion batteries… have transformed everything from drones to electric boats,” said Samuel. Originally developed for mobile phones, these batteries offered far greater energy density, faster charging, and much longer life cycles than their predecessors.
Their impact on the EV industry was immediate and profound. “They’re absolutely the standard now,” Samuel noted. “And they’ve enabled the kind of performance and range that consumers expect.”
But even lithium-ion has its limits—particularly when it comes to grid-scale storage and long-duration energy needs. That’s where Samuel’s later work with Vanadium Redox flow batteries comes in.
Flowing Forward: Vanadium and the Grid
After decades in vehicle development, Samuel turned his attention to energy storage for renewable integration. “We still hadn’t got a decent battery,” he said. “So I went to work on a new type of battery altogether… a redox flow battery using Vanadium.”
Unlike conventional batteries, flow batteries store energy in liquid electrolytes that circulate through a cell stack. “It works a bit like a fuel cell,” Samuel explained. “The big advantage is that you can put a large fuel tank on it and go for many miles—or store energy for many hours.”
This technology, now commercialised by Invinity Energy Systems (IES), is particularly well-suited for managing the intermittency of solar and wind power. “It’s what’s called a long-duration energy storage system,” Samuel said. “Lithium is efficient up to about four hours. Vanadium can go up to twelve hours.”
The Power Electronics Revolution
While batteries often steal the spotlight, the unsung hero of EV performance is power electronics—the systems that control how electricity flows through the vehicle. This is where Pete James, co-author of the book and a specialist in the field, made his mark.
“In the 90s, there was a huge development in power electronics,” James explained. “New transistors came available—IGBTs, MOSFETs—that allowed us to handle power much more efficiently.”
These components enabled the shift from clunky, inefficient DC motors to sophisticated A/C drives with regenerative braking and precise control. “It was an absolute transformation,” said Samuel. “We couldn’t do that in the old days with chopper controls and switchgear.”
James’ company, Lyra Electronics, has worked on everything from traction drives and onboard chargers to fuel cell applications. “It’s a fantastic feeling when some electronics you’ve designed makes a two-tonne vehicle move,” he said.
Smaller, Smarter, Cheaper
As EV adoption grows, the next frontier is miniaturisation and cost reduction. “We’ve shown that power electronics are reliable and efficient,” James said. “Now we need to make them smaller and more cost-effective.”
This push is not just about saving space—it’s about making EVs affordable for the mass market. “We need to bring the cost of electric vehicles down so that everybody can afford them,” James emphasised.
He also pointed to the growing complexity of vehicle systems. “There can be 60 to 120 computers on board a vehicle today,” he noted. “There’s a big move to consolidate them, which will influence how batteries and power systems are designed.”
Looking Ahead: Sodium, Solid-State, and Beyond
Both Samuel and James are optimistic about the future of battery technology. “There are some interesting battery technologies coming out,” James said. “Sodium and solid-state batteries could offer new advantages in cost, safety, and performance.”
Solid-state batteries, in particular, promise higher energy density and faster charging without the flammability risks of liquid electrolytes. Sodium-ion, meanwhile, could reduce reliance on scarce and expensive materials like lithium and cobalt.
Conclusion: The Quiet Engine of Progress
The EV revolution may be visible on the roads, but its true engine lies in the labs and workshops where engineers like Samuel and James have spent decades refining the invisible systems that make electric mobility possible.
From the first lead-acid prototypes to today’s high-performance lithium-ion vehicles—and tomorrow’s solid-state dreams—the story of EV technology is one of relentless innovation.
As Samuel put it: “People thought we were totally nuts back in 1970. But as well as EV’s we’ve just got to have clean fuels… and this book gives a really broad view of where the industry is going.”
Further Reading: Dive Deeper into EV Technologies
For readers eager to explore the full story behind the innovations discussed here, John Samuel and Pete James have co-authored a comprehensive book titled Electric VehicleTechnologies: Renewable energy for the road, available through the IET Bookshop.
This book offers a deeper dive into the evolution of EV systems, from battery chemistry and power electronics to charging infrastructure and future trends. Whether you're an engineer, student, or simply curious about the silent revolution reshaping transport, Electric Vehicle Technologies provides expert insights from two pioneers who helped shape the field.
Electric Vehicle Technologies: Renewables energy for the road available now in print and digital formats at the IET Bookshop: https://shop.theiet.org/electric-vehicle-technologies