Electric vehicles (EVs) could offer significant environmental and air quality benefits but only if the charging problem is effectively solved. The ultimate aim is to make charging as convenient and fast as filling up with gasoline or diesel; the trouble is that the industry is not there yet. Plugs come in various configurations that only work with certain stations. For drivers living in urban centres, on-street charging opportunities are few and far between. Long cables stretched out alongside busy city streets and crowded pavements can pose a safety hazard and an eyesore.
Wireless charging could address some of these challenges and is attracting a growing list of big name automakers.
Tackling pain points
This approach allows EVs to charge by simply parking over a ground pad. Energy is provided from a magnetic resonance system in the ground; a vehicle parks over the spot and takes in the energy via a receiver embedded in its structure. The technology holds a particular attraction for fleet vehicles like taxis, with the promise of minimising time spent charging and thus optimising uptime.
Plenty of stakeholders are drawn to the convenience aspect and are investing time and money in it. In the UK city of Nottingham, nine electric taxis are currently participating in a wireless charging trial in a project funded by the Office for Zero Emission Vehicles (OZEV). The vehicles—a mix of modified LEVC TX and Nissan Dynamo taxis—sport a special livery to promote the WiCET (Wireless Charging of Electric Taxis) branding, with the message, ‘This electric taxi will charge wirelessly.’ For the project, Sprint Power developed an electrical distribution system, a power distribution module and a high voltage harness assembly that will enable the vehicles to receive the wireless charge.
“Wireless charging technology has clear commercial and consumer experience opportunities but most importantly could help address some accessibility challenges associated with charging an EV,” comments Abdul Chowdhury, head of innovation at OZEV.
Elsewhere in the UK, local company Char.gy is running a 12-month wireless charging trial using a fleet of ten modified Renault Zoe EVs. The project has started in Marlow but is expected to spread to nine additional locations across the country.
More recently, the Swedish city of Gothenburg announced it would launch a new three-year wireless charging pilot. Leading taxi operator Cabonline will run a small fleet of electric Volvo XC40 Recharge taxis that will charge wirelessly at stations across the city.
The automaker perspective
Volvo is just one of several big name automakers committed to an electric future. The company set a precedent when it became the first major premium car brand to commit to a hybrid or full-electric powertrain for its entire line-up. By 2025, it expects half of its global sales to be fully electric. Wireless charging could have a role to play within that vision.
Mats Moberg, Head of Research and Development at Volvo Cars, describes the Gothenburg pilot as “a good way to evaluate alternative charging options for our future cars.” The benefits, in his view, include an improved user experience with hassle-free charging as well as air quality benefits without the clutter of cables and power cabinets on the streets. He also flags ‘unlimited life and high durability of the infrastructure equipment’ as additional draws of a wireless setup. “We believe that wireless charging fits well into the Volvo brand image,” he reiterates.
Any invention related to the laziness of people will succeed in the end
In this instance, the wireless technology comes from Momentum Dynamics. Charging pads are embedded in the pavement along certain taxi ranks. The charging process starts automatically when the Volvo XC40 parks over a pad. The vehicles will use Volvo’s onboard 360 camera to guide drivers to the charging position. However, additional adaptations will be needed for the vehicles to fully facilitate the acceptance of a wireless power transfer. “It is very much an integration task to fit the new components into the existing vehicle,” Moberg tells Automotive World. “It is all about mechanical, thermal, electrical, and software adaptations.”
While this particular pilot involves a taxi fleet, other use cases could prove a good fit for wireless charging, such as car fleets in general that rack up substantial miles every year. “High mileage traffic can benefit due to higher usage factors,” Moberg emphasises. In the future, autonomous vehicles may require wireless charging capability, as there is no driver in the vehicle to plug it in. Some companies, including BMW, are targeting private consumers as well.
Various players, including automakers like Nissan, BMW and Renault, have been exploring wireless technology for many years. In fact, the BMW 530e inductive charging pilot programme was named 2020 Green Car Technology of the Year by Green Car Journal. However, it has yet to take off in any meaningful way. Cost levels and a clear business case have proven headwinds. So has a lack of standards. “Previously the lack of standards was a big obstacle,” says Moberg. “The standard is now set for up to 11kW, but not for charging with higher power yet.” In Volvo’s pilot, the wireless charging power will be more than 40 kW.
In autumn 2020, The Society of Automotive Engineers (SAE) finally outlined the first global standard for wireless EV charging, SAE J2954, but as Moberg notes it covers inductive-charging systems up to 11kW only. “Charging your EV should be as simple as parking and walking away—the wireless charging SAE J2954 standard gives freedom to do exactly that, safely and automatically,” Jesse Schneider, Chair of the SAE J2954 task force, said at the time of the announcement. The task force had started work on the standards back in 2007. During the intervening years the industry was improving its efficiency, and the technology finally reached the point where systems with a 10-inch ground clearance could achieve 94% grid-to-battery efficiency.
With standards now in place, interest will likely grow and developments could gain momentum. There are still plenty of unknowns, including what users think of the experience. That’s what the ongoing pilot projects could help with. “The recently launched project within the frame of the Gothenburg Green City Zone initiative will tell us about the driver acceptance experiences of this technology,” notes Moberg. “We do this to learn and will base possible future decisions on the experiences we will gain through this project.”
So too will others. For now, plenty of industry players still regard wireless as an interesting academic exercise that remains too immature to pay much attention to. Finnish charging provider Kempower falls into that group, but its Chief Executive Tomi Ristamäki admits it has long-term potential, particularly for its convenience. “Any invention related to the laziness of people will succeed in the end,” Ristamäki tells Automotive World.