Large electric vehicles are not sold on up-front price but on performance and cost over life. They are mainly bought by government including local government, the military and with government funding of others. Innovation is therefore usually first seen in large electric vehicles. Buses are the most successful of these with a huge growth ahead, so supercapacitor, supercabattery and battery manufacturers have converged on these for a battle of options.
Bombardier, Volvo and ABB seem to favour fast charging Li-ion traction batteries in pure electric buses, for example with lithium titanate anodes though silicon based anodes get major research attention now. What will silicon really achieve? Those buses appear to have no need for supercapacitor protection, tearing up the rule book that says that one of the most damaging things to hit a lithium-ion battery is pulses of power and lithium iron phosphate cathodes are particularly poor.
Opposite stand those arguing that the market will not swing entirely to pure electric, the MAN hybrid urban bus having supercapacitors and no traction battery like the Toyota Formula One racer. Sinautec pure electric buses with supercapacitors have no traction battery, and there is no longer a need to recharge at every bus stop. Theoretically, supercapacitors and supercabatteries can match Li-ion battery energy density as it rises to 300 Wh/kg and maybe eventually 1000 Wh/kg. A healthy contest has begun. Suppliers benefit as they use IDTechEx advice on future winners and losers and gaps in the market eg power electronics explored in the IDTechEx report, Power Electronics for Electric Vehicles 2013-2023.
There is even contention about whether contactless inductive charging is the future and whether it will be feasible for the fastest charging of buses. Can regenerative braking be fully optimised with batteries alone? When will multiple energy harvesting be viable? We are promised a very useful 12kW per bus from energy harvesting shock absorbers when they are commercial, first in large vehicles, says maker Levant. The demise of Better Place has not resulted in battery swapping being abandoned for fleets of buses: it is the norm for fleets of forklifts but not with Li-ion in them.
Watch buses for answers that will hit small electric vehicles much later. IDTechEx analysts have the world's most comprehensive range of reports and consultancy services on electric vehicles. See, Hybrid and Electric Buses and Taxis 2013-2023: Forecasts, Opportunities, Players, Industrial and Commercial Electric Vehicles 2013-2023 and the big picture in, Hybrid and Pure Electric Vehicles Land, Water and Air 2013-2023.
See the general report, Electrochemical Double Layer Capacitors, Supercapacitors 2013-2023, the drill down, Supercapacitor/ Ultracapacitor Strategies and Emerging Applications 2013-2025 and reports on batteries, including lithium-based batteries that do not involve the intercalation that defines Li-ion batteries.
