Wireless power transmission for consumer electronics and EVs
2011年9月19日 Dr Peter Harrop
Over the next decade, the most vibrant Wireless Power Transmission (WPT) markets will be the contactless charging of portable and mobile equipment, in particular consumer electronics and electric vehicles. This is the focus of a new IDTechEx report, Wireless Power Transmission for Consumer Electronics and Electric Vehicles 2012-2022. In this article we share some of the research carried out for this report. It describes technologies that will be a stepping stone to contactless power for a high proportion of static consumer, industrial and military electronics and electrics. For now, it primarily concerns wireless charging of batteries in portable consumer electronics and in electric vehicles. Both travel considerable distances and ready availability of standard, convenient, contactless, charging capability are key to their further growth in adoption. For example, the user will enjoy ever greater functionality and longer hours of use of mobile phones despite the on-going shortcomings of their batteries.
Our research concerns transfer of watts up to high power of the order of kilowatts at ranges of about one millimeter to about 60 centimeters. The WPT of concern usually involves static transmitters and a larger number of receivers incorporated in what is usually portable or mobile equipment. The transmitters are usually hard wired to AC mains or energy harvesters such as photovoltaics, there being a trend towards multiple energy harvesting. It will only become a mass market if more comprehensive standards are widely adopted and the manufacturers of the portable and mobile equipment incorporate the receivers during manufacture. We forecast the demand by power level and consider other criteria such as technology, range and region of adoption.
The extreme inconvenience of the proliferation of electrically charged products each with an incompatible charging power supply, must be overcome. Three to four billion units are made every year - a potential market for wireless charging pairs of up to ten billion dollars yearly, given market growth and an allied market of wireless power to electronic and electric consumer products that do not need charging. Indeed, the massive disposal of non-standard external power supplies for consumer electronics is an environmental outrage of concern to governments. Only 15-20% by weight of electronic products including laptops, cell phones and their power supplies are recycled. A typical user of electronic devices now carries at least three different chargers and at least an equal number of cables for energy charging and data transfer functions. However, we all know about the cordless electric toothbrush and there is now a consumer demand to charge mobile devices wirelessly, eliminating most wiring.
Traction batteries not improving fast enough either. Those using pure electric cars seek to avoid range anxiety in some other convenient way. Standing in the rain to plug in an electric cable which then trips off for safety reasons does not qualify though almost all the investment in vehicle charging infrastructure is currently going into just that. Convenient electric top up of hybrid electric cars is also an important market driver as they become capable of all electric range of more than 100 kilometers, creating the opportunity to pay one fifth as much for "fuel" due to a quirk in the taxation system (electricity is cheap) and to save the planet as power stations get cleaner. It has been established that, as with gasoline pumping, a high proportion of women in particular find it unpleasant and even dangerous to get out of the vehicle and plug in for electricity. With WPT they stay clean and safe inside the vehicle.
WPT for consumer electronics and electric vehicles is in its infancy. Most production consists of a transmitter and receiver pair, though the receiver will increasingly be sold as part of the original equipment. In the following decade, the number of transmitters sold may somewhat exceed the number of transmitters as architects, coffee shops and others widely deploy them for consumer electronics as a convenience for the public, emulating the spread of WiFi, for example. Indeed, the leading producer of standards for WPT aimed primarily at consumer electronics, the Wireless Power Consortium WPC, specifically models its work on the success of WiFi. Interestingly, it and its members have ambitions for the smaller electric vehicles being charged with its technologies and to its standards.
There are huge uncertainties in forecasting the adoption of WPT in consumer goods. For example, Apple, which steers clear of most standards making, could adopt it for its products creating a multi- billion dollar business very rapidly. Consumer goods are becoming electronic and here just one leading brand could take one billion receivers yearly. On the other hand, the need to increase the cost of highly price sensitive consumer products in order to offer something that may not be valued is a severe damper as is the lack of standards for more than five watts.
Historical lessons of both consumer electronics and electric vehicles are that infrastructure-related change is slow. Consider Near Field Communication NFC in mobile phones, where standards were globally adopted some time ago but adoption is grindingly slow outside Japan, the one country that got its act together. Contrast the even worse situation with wireless charging of phones, where virtually no infrastructure is in place and the standards are recent and disputed. We therefore forecast modest business until a tipping point is reached around 2020 when it is seen as a realistic solution to drained batteries when on the move. In other words, by then, many devices will be chargeable on standardised publicly available wireless chargers.
As with contactless charging of cars, there is little incentive to buy the facility if it can only be used at home. The primary benefits of contactless charging relate to being able to use it wherever the need arises but there is also a potential cost advantage to the user, though not to the supplier, in removing the plethora of non-standard external chargers of consumer electronics. That said, there is now an agreement to standardise wired power supplies to a mini-USB port in much of the world - a threat to contactless charging. Low power devices will be first with WPT adoption: there is a widely accepted standard in place.
Electric vehicles have something of the same chicken-and-egg problem of consumer electronics of, "Why buy it if you cannot yet use it in public places?" vs, "Why install public stations if the equipment is not widely available to use it?" However, with electric vehicles, there is a substantial fleet market that can be early adopters, some even using the dynamic form (continuous charging from laid cable) not seen or needed with consumer electronics ie equipment being continuously charged by wiring in the road.
Electric vehicles purchased by the public differ from consumer electronics in that they are not an impulse buy and designs change only slowly. We do not therefore see a tipping point where cars, for example, suddenly have contactless charging widely adopted in public places. This is despite the fact that most plug-in charging stations are currently funded on a non-economic basis by government and electricity generating companies as part of their green image. Such largesse is unlikely to be widely repeated with contactless vehicle charging, which will widen adoption because it is more convenient but which wastes more power, so it is less green. Indeed, it has a higher installation cost in many cases, involving digging up roads, and it awaits standards whereas at least there is one standard for the lower power charging of consumer electronics.
For electric vehicles, the transmitters (charging stations) are by far the largest element of cost and therefore the main focus of attention. We forecast them, with the assumption that standards for up to 10kW will be written and widely adopted within the next five years. Meanwhile, fast vehicle charging with contacts is being standardised and practised up to over 20 times that figure. This is detailed in the IDTechEx report, Electric Vehicle Charging Infrastructure 2011-2021. In 2020, over 3.6 million vehicle charging stations will be installed, contacted and contactless, residential and public. Mostly this will be for hybrid cars because they will still outsell pure electric cars and have useful all electric range in these later years, so plugging in becomes more worthwhile, saving significant cost. Already, a surprisingly large number of organisations are involved in WPT for both consumer electronics and vehicles and the report profiles many of them.
Learn more live at the IDTechEx Energy Harvesting & Storage event, November 15-16 2011, Boston, USA. Hear from Fulton Innovations, Leggett & Platt and WiTricity discussing the progress with wireless power.
Top image source: Techno Geeks