But with so many domestic EV charging technologies currently in development, it’s not yet clear which will come out on top.
A total of 190,000 new battery electric vehicles were sold in the UK last year, according to data compiled by the SMMT, and with just around 26,000 charging points currently available across the country, there is growing concern that this is insufficient to meet future demand. National Grid has predicted that there could be as many as 11 million EVs on Britain’s roads by 2030 and 36 million by 2040.
A number of domestic charging solutions are currently under development, which could emerge as the dominant technology in the next few years. The main focus is split between developing technologies suitable for domestic and on-street charging, which operate using an alternating current (AC) and charge at a slower rate, and those suitable for high-capacity charging stations, which provide a direct current (DC) that directly charges the battery.
The idea of charging EVs at home certainly has some appeal for motorists, due to the convenience of having a dedicated power source and access to a domestic electricity supply. However, it can take six hours or more to charge an EV at home, due to the use of a lower power alternating current systems, and depending on how regularly the vehicle is being used, this could be a limiting factor. Also, about a third of households in the UK don’t have a driveway, so installing a charging point on the front of the house is not always an option.
Wireless and inductive charging
To address some of these limitations, a number of automakers and innovative collaborations are developing user-friendly, wireless or inductive charging technologies. The volume of PCT patent applications filed at the World Intellectual Property Office (WIPO), which are related to inductive charging technologies, has doubled in the past decade. This reflects an increase in the amount R&D in this area. For example, EV charging infrastructure innovator, char.gy, recently announced that it is trialling an inductive charging system in Marlow, with its technology partner, IPT Technology. Backed by the Office for Zero Emission Vehicles (OZEV) and Innovate UK, the innovative system makes use of existing grid infrastructure from lampposts in the area and an inductive charging pad placed on the road surface or installed in the ground or a parking bay.
Other inductive charging trials are underway around the world. For example, a trial is currently underway in Sweden to test a wireless charging system, developed by Israeli company, ElectReon. The technology is built into the surface of the road, so batteries are charged while vehicles are on the move. A project underway in Michigan, is also testing an inductive vehicle charging system, which involves embedding conductive coils into the road surface. In China, Qilu Transportation Development Group Co, is trialling an ‘intelligent highway’ fitted with solar panels, sensors and other technologies to facilitate autonomous motoring, more accurate mapping and on-the-go charging of EVs.
In order to transmit power wirelessly, it is necessary to have a source and receiver. The source is typically placed on the road surface or in the ground, and the receiver is fitted to the underside of the vehicle. The source is a transmitter coil, which when powered by electricity, forms a magnetic field. To operate effectively, close coupling and alignment of the source and receiver is required prior to charging, to avoid energy loss. To overcome this problem, MIT in the US has developed a technology known as magnetic resonance power transfer. The source and receiver are tuned to the same resonant frequency, creating a tunnel-like magnetic field, which means it is no longer necessary for the source and receiver to be so closely aligned.
WiTricity Corporation is the exclusive licensee of MIT patents for wireless energy transfer globally and the company is responsible for nearly 600 patents and patent applications directed to its own innovations, which build on these technological foundations. Recently, WiTricity acquired Qualcomm Halo, adding further wireless EV charging patents owned by Qualcomm and other exclusive licensing rights to its portfolio. Already the owner of many emerging standard essential patents, the company is well placed to become a tech leader in this fast-developing marketplace.
As electric cars continue to gain popularity, so it becomes increasingly important that steps are taken to take pressure off the grid at peak times. This is encouraging innovators to focus more on vehicle-to-grid (V2G) solutions, such as wireless EV charging technologies with bidirectional functionality, which allows electric vehicles to support the grid when demand exceeds baseline supply.
BMW has been working on the development of bidirectional charging management (BCM) for some time. In July last year, it announced that it had produced 20 BMW i3 models for customers, which are capable of taking energy from the network and feeding it back if needed, with thirty more to follow. The technology package provides everything needed to ensure their vehicle and wallbox are connected to the customer’s building, with bidirectional access to its power supply.
Other car makers are developing V2G infrastructure, including Fiat, which began installing V2G charging points at its Mirafiori factory in Turin in 2020. Audi also began trialling vehicle-to-home (V2H) technology on some of its e-tron SUVs last year. Nissan and EDF have also teamed up to launch a new commercial charging service for fleet operators, which uses V2G technology to return energy to the grid during peak hours and recharge when energy rates are cheapest. Other dynamic/smart charging technologies are being developed alongside V2G solutions, potentially allowing motorists to charge their vehicles at cheaper rates overnight. Also, with dynamic charging, EV batteries could be a store of surplus renewable electricity generated overnight, which would otherwise be under-utilised.
While V2G wireless EV charging technology is an exciting proposition for motorists and car makers alike, it is unlikely to be sufficient in itself to support wider take up of EVs. Sustained investment in high-power EV charging stations will be needed to facilitate travel over longer distances and eliminate concerns about range anxiety.
For businesses investing in the development of EV charging technologies, the opportunity to secure a stake in this fast-developing marketplace by securing global patents to protect their innovations, is an opportunity that they can’t afford to miss.
Diego Black is a partner and patent attorney in the Electronics, Computing & Physics group at European intellectual property firm, Withers & Rogers.