Battery technology and costs are top R&D priorities for enabling the success of hybrid and electric vehicles, according to Dr. Peter Harrop, Chairman of IDTechEx, a U.K.-based consultancy. And motors and electronic control systems (including telematics) are becoming more expensive due, respectively, to increasing rare metal costs and complexity.
He said achieving success "revolves mainly around getting battery costs down and performance up, particularly improving energy density and therefore electric range and cost for pure electric and plug-in hybrid electric vehicle applications.”
Third-generation lithium-ion batteries will become available sooner than expected, Harrop believes. And plug-in technology for hybrids has emerged as the way forward commercially.
“The most aggressive manufacturers will be selling more plug-in than traditional hybrids by the end of the decade,” he predicted. “But for that to happen, the price premium must be small or nonexistent—and the all-electric range be useful rather than a token gesture.”
IDTechEx’s forecasts are compiled by analysts who monitor the work of companies, universities, and research institutes across the world, together with conference speakers’ statements. Looking forward 10 years, the forecasts spotlight the importance of energy harvesting, supercapacitors/ultracapacitors (doing more of the work of batteries), and range-extended hybrids.
He regards the likely transfer of KERS (Kinetic Energy Recovery Systems) from racetrack to road cars (Volvo is now trialing the system) as significant, with any motor that can regenerate braking energy becoming the norm. “And shock absorbers generating energy are soon to be very important," he said.
Photovoltaics with much wider area, and therefore power, are also being trialed by some companies in forms that include conformal, transparent, and unfolding.
Heat-harvesting thermoelectrics such as those that BMW engineers are developing with the company's so-called Autosteamer (see SAE Technical Paper 2009-01-0174: Rankine Cycle for Waste Heat Recovery of IC Engines) are regarded by Harrop as “creeping towards adoption.”
But there is far more to come: “We see multiple-energy-harvesting as a key part of working around the battery problems,” he told AEI. Improved circuitry and EV fast-charge stations are also important.
Only a year ago the importance of range extenders was not generally appreciated, explained Harrop. Recently the Chevrolet Volt/GME Ampera has shown that configuration's potential with useful electric range. Harrop noted his company’s forecasts for the configuration’s application show that in the next decade some 30 million vehicles worldwide will use range extenders.
But he warned that automakers will not realize the full potential of range-extended hybrids unless they develop purpose-designed engines for them, rather than adopting modified versions of existing ICEs. His quaint analogy for such a practice: “It is equivalent to teaching a tortoise to fly!”
As battery and other associated technologies mature, range extenders will seldom be activated during a journey, needing just to supply electricity, noted Harrop. “They do not need to rotate and they certainly do not have to employ a shaft to a separate generator in the clunky old ‘box-on-box’ approach of yesteryear," he explained.
That means that future range extenders may include such things as Wankel and free-piston engines swathed in coils to generate electricity, with no protruding shaft. Such "fuel generators" are being developed, he said.
As reported by AEI, Lotus and others have developed twin- and three-cylinder range extenders, and Jaguar has even put Bladon micro gas turbines into a concept. And the quiet-running Polaris Industries Swisscom single-piston extender (it has no oil pump) has been demonstrated in an electric van.
Traction motors also have surged up the R&D priority scale, due to concerns over the escalating cost and availability of rare-earth elements, particularly dysprosium and neodymium. What Harrop terms “serious suppliers” are therefore trying to develop better magnet-free motors, particularly asynchronous and switched-reluctance synchronous types.
Asynchronous motors are increasingly appearing in smaller vehicles, and efforts also are being made to develop motors using fewer magnets or magnets that do not use rare-earth metals. But a number of traction motor manufacturers continue to employ conventional magnets—and “many even stick with motors that have brushes,” Harrop observed.
In-wheel traction motor designs are financially problematic, he believes, due to the necessary development of new dedicated platforms and the cost of using two or four small motors instead of a single larger type. Although application of in-wheel technology may bring a reduction in overall powertrain and chassis part numbers, this may not always be sufficient to offset the cost of the extra motors, Harrop believes. The technology initially will find applications in military and large vehicles and in e-bikes, he said.
As for the possibilities for fuel cells, Harrop is cautious. He believes they will mainly be used not as the prime energy source of EVs but as range extenders. Developers are working to reduce or eliminate the platinum content in fuel cells, but other challenges remain such as through-life costs and hydrogen fuel distribution.
“Nevertheless, they are appearing in a few fleets of EVs from forklifts to buses, where these challenges are more manageable—and the first limited rollouts in cars are imminent,” he opined.