Juicing electric cars though manhole covers among new wireless charging experiments
Next year, some manhole covers in New York City will double as wireless-charging stations for electric vehicles equipped with wireless receivers.
Also in 2014, Toyota plans to test a wireless charging Prius in Japan, Europe and the U.S.
Auto electronics giant Delphi has partnered with WiTricity, the first company to create wireless vehicle charging pads, and is developing technology for hybrid and fully electric vehicles (EVs) that could be used industrywide.
As hybrid and electric vehicles gain popularity, consumers also want them to be as simple to power up as gas-fueled cars and trucks. One way to do that is to remove the charging wires and have the vehicles recharge simply by parking over a wireless charger. Imagine, for example, delivery trucks that never need to refuel because there are “green zone” parking spaces that offer automated wireless charging.
According to research firm IHS Automotive, fast-charging technologies, such as those at WiTricity and New York City-based HEVO, are driving the growth of the electric vehicle charging market.
The number of wireless charging stations established worldwide is expected to climb by a factor of more than 100 from 2012 to 2020, according to IHS Automotive. Fast-charging stations for EVs are set to reach 199,000 locations globally in 2020, up from just 1,800 last year.
“The number of these stations, meanwhile, is anticipated to rise more than threefold in 2013 to 5,900 and then nearly triple to 15,200 in 2014. Overall growth will continue at a rapid pace through 2020,” IHS stated in its report.
HEVO’s manhole cover chargers
HEVO, which stands for hybrid and electric vehicle optimization, partnered with New York University, and will use two wirelessly equipped Smart Fortwo electric cars to test the practicality and efficiency of the manhole chargers.
HEVO, however, is focused on the bigger business of powering commercial electric fleets owned by companies such as Frito-Lay and Pepsi.
What HEVO’s wireless-charging manhole parking spaces may look like in New York City. (Photo: HEVO Power)
Like all wireless charging technology for automobiles, HEVO’s manhole covers work via electromagnetic resonance, which makes a magnetic connection between a charging coil to a car equipped with a wireless charging coil.
HEVO has also garnered interest from the cities of Santa Monica, Calif., and San Francisco for tests in early 2014, but there have been no commitments yet, according to Gregory Stahl, HEVO’s chief marketing officer.
HEVO did not disclose the cost of its wireless charging manhole covers, but said the technology will be competitive with other systems already on the market at prices ranging between $3,500 and $5,000.
One major stumbling block to widespread EV adoption is the length of time it takes to recharge vehicle batteries.
While it takes a few minutes to refuel a gas-powered vehicle, the recharge time for EVs is about four hours for a 24 kilowatt-hour (kWh)-capacity battery using a 6.6 kW on-board charger, according to Alastair Hayfield, associate research director at IHS Automotive. Such a battery would work on a standard size economy car, such as the Nissan Leaf.
“If EV auto manufacturers could overcome this obstacle, it could lead to a high rate of adoption from environmentally minded consumers as well as those seeking to cut gasoline expenses. That’s where fast charging comes in,” Alastair said in a recent IHS report.
HEVO units are comparable to Level 2 charging plug-in stations used by EV fleets, which typically take eight to 12 hours per day to charge, according to Stahl. “We can charge up to three times faster than many wireless competitors at up to three times the distance,” he said.
“Regardless of battery capacity, these figures remain the same,” Stahl said in an email reply to Computerworld.
WiTricity’s charging technology offers up to 25kW, with the company’s systems for passenger cars outputting from 3.3kW to 6 kW while systems for fleets and small buses are in the 10kW to 25kW range.
WiTricity claims it takes the same amount of time to charge a vehicle wirelessly as it would plugging it in, which in a passenger car with a dead battery is nominally four hours.
However, one emerging technology is fast-charging systems, which offer a high-voltage DC charge instead of a slower AC charge. With a fast charging station, a vehicle can be fully charged in as little as 20 minutes, according to Hayfield. “This could be a major step toward EVs becoming generally equivalent to (gas-powered) vehicles when it comes to refueling,” Hayfield said.
One fast-charging standard designed for electric vehicles is CHAdeMO. The major proponents of the technology are Japanese automakers, including Toyota, Nissan, Mitsubishi, and Japanese industrial giants such as Fuji Heavy Industries Ltd. and Tokyo Electric Power Co. to name a few.
According to IHS Automotive, there are as many as 2,445 CHAdeMO fast chargers in operation and more than 57,000 CHAdeMO-compatible EVs around the world, which accounts for 80% of all EVs on the road. The highest concentration of EVs comes from Japan in the form of the Nissan Leaf, Mitsubishi i-MiEv and Honda Fit EV among others.
Hayfield pointed out that fast charging and wireless charging are two distinctly different technologies.
“Beyond the longer charge time with wireless... there are many other factors which make its adoption a long term trend,” Hayfield said of wireless charging.
Among the obstacles that wireless charging must overcome is that it’s currently not in production; it must be added aftermarket. Also, the magnetic coil charging system adds weight and cost the the vehicle, Hayfield said.
“Public trials are really only just beginning now. There are safety and interference issues that must be tested in the real world,” she added.
Additionally, while wireless charging is supposed to add a level of convenience for EV owners, “plugging in is not a major problem for most,” Hayfield said.
Efficiency is key, size matters
Another drawback to wireless charging is power loss. Transferring electricity through the air between two copper coils means some power will dissipate.
HEVO’s wireless charging devices have a power transfer efficiency of more than 85% at 12 inches of separation, according to Stahl.
Eric Giler, WiTricity’s CEO, said anything under 90% end-to-end efficiency should not be acceptable.
“Think about it. If you’re transferring 10,000 watts, and if you’re at 85% efficiency, you’re continually wasting 1,500 watts of electricity. Even at 90%, you’re still wasting 10,000 watts. That’s a lot of energy to waste,” he said.
HEVO’s Power Station technology comes in three parts: a power transmitter—a coil that can be embedded in the pavement or an object; a receiver in a vehicle and a smartphone app. The app can be used to find wireless charging parking spaces, and can also tell the driver when the vehicle is aligned properly for charging.
HEVO’s Power Station transmits at 220-volts with up to 10 kilowatts of power for charging a vehicle. The larger the copper coil, the more power that can be transferred.
WiTricity, originally a research project at MIT, was formed in 2007 after scientists demonstrated they could use two copper coils to create a magnetic field and power a 60-watt light bulb wirelessly. To date, the company has garnered more than $40 million in venture capital funding, the last round being led by Toyota.
Today, the company licenses its technology to equipment makers in the consumer, healthcare, industrial and automotive markets. By far, Giler said, the largest markets are consumer and automotive. Along with Delphi and Toyota, Mitsubishi has also partnered with WiTricity to develop charging pads.
WiTricity’s 3,300 watt wireless charging pad (Source: WiTricity).
Mobile technology company Qualcomm has also announced that its Halo wireless charging technology will be used in tests to charge EVs around London and to recharge safety vehicles working on the Formula E car racing circuit.
Qualcomm’s Halo pads would charge a car as long as a driver pulls to within eight or nine inches of the charging pad. An indicator on the vehicle’s dashboard signals when the charger is engaged.
Along with Qualcomm, Delphi and Siemens are in partnerships to develop inductive charging technology, including mats that can be placed in garages or parking spaces.
Siemens estimates the installation cost of both the charging mat and in-vehicle charging coil would run about $2,000, about twice the cost of a corded charger.
How wireless charging works (Image: WiTriCity)
As with any nascent industry, there are competing standards and their consortiums.
Currently, the wireless charging industry is divided into three standardization camps, each headed by market leaders competing for dominance.
Qualcomm and Samsung, for example, are founders of the Alliance for Wireless Power (A4WP), which competes with the Wireless Power Consortium (WPC) and the Power Matters Alliance (PMA). Companies, however, are hedging their bets and are sometimes members of one alliance while still using technology from another. For example, the WPC supports the widely adopted Qi (pronounced “chee”) standard used in Nokia, Samsung and LG products.
There are two forms of wireless charging: magnetic induction, which is the most prominent, and magnetic resonance.
Both charging techniques use the same basic technology. Alternating current in a transmitter coil generates a magnetic field, which induces a voltage in the receiver coil.
Magnetic induction charging techniques, however, require that the device being charged is in contact with a charging surface, such as a charging pad. That leads to greater power transfer efficiency. The leading charging pad supplier has been Duracell’s Powermat technology.
Magnetic resonance charging, like WiTricity’s or HEVO’s, allows an enabled device to be placed up to several feet away from a power source for charging. However, the closer the receiver and transmission coils are to each other, the better the charging efficiency.
WiTricity has created more than a half-dozen prototypes for its wireless charging technology. The tech can be used to charge smartphones, TVs, entire rooms of equipment and even electric cars at relatively long distances.