• Sukhjeet Singh

Wireless Battery Charging Solution for Electric Vehicles (EV)

The year 1886 is regarded as the birth year of the motor car when an inventor named Karl Benz patented his Benz Patent-Motorwagen. Since then, the technology in the motor car market has evolved enough to provide us with more than mere facilitating humankind to go from one point to another. Around 1.4 billion cars are running around the globe, and according to Statista, worldwide automobiles sales are expected to grow from 63.8 million units in 2020 to 71 million in 2021. This number is expected to grow to 93 million in the year 2025. One adverse thing which also grows with the increase in the number of automobiles is air pollution. According to WHO, air pollution results in 4.2 million deaths per year as a result of exposure to ambient air pollution, 3.8 million deaths as a result of household exposure to smoke from dirty cookstoves and fuels, and 9 out of 10 people worldwide live-in places where air quality exceeds WHO guidelines. One cannot say that automobiles are solely responsible for degrading the air quality. Still, given the data above, it reflects that automobiles are major contributors to increasing air pollution due to the regular emission of carbon content from the fuel burnt inside the automobile engines.


In response to the growing air pollution, electric vehicles were introduced in the market. Ferdinand Porsche created the world’s first hybrid car named as Lohner-Porsche Mixte. This car was powered by electricity stored in the battery and a gas engine. This hybrid technology has also evolved with time, and today we can see cars that can only run-on batteries. By the end of 2020, there will be approximately 1.3 million battery-electric vehicles on the road in the United States, with over 7 million globally.



The graph above depicts the trend in the number of electric vehicle sales from 2010 to 2020 in the world's largest automobile market, China. Electric vehicles provide a number of advantages over vehicles with internal combustion engines, including lower maintenance costs and higher performance.


But infrastructure required to employ a full-fledged operational system for Electric vehicles like charging points, repairing shops, etc., is still not sufficient. Unlike conventional internal combustion engines, research for successful deployment of the Electric vehicle system is still going on, with better results coming up each day. One such requirement or need of the hour is to establish sufficient car charging points for Electric vehicles. In a world where charging electric cars is a crucial point in boosting the energy transition, wireless charging can be an essential factor that can decide the future of Electric vehicles in markets around the globe.


Top 10 Electric Vehicles Sold in the United States, 2020

Company

Number of Vehicles Sold

Tesla

200,561

Chevrolet Bolt EV

19,664

Nissan Leaf

8,972

Audi E-tron

7,089

Porsche Taycan

3,943

Hyundai Kona EV

2,964

Kia Niro EV

2,807

How Does Wireless Charging for Electric Vehicles Work?


Today many of us charge our smartphones, tablets, and watches without wires, just by placing them on a wireless charging pad. Therefore, an obvious question arises - Can we do the same with Electric vehicles i.e. can charge them wirelessly. Well, at a technical level - yes! Although wireless charging of Electric vehicles is still an ongoing project for many automobile companies like BMW, we may see the fruit of their hard work and intelligence in the coming years. Already, an Electric car-Genesis GV60 is about to go on sale in the year 2022 and has hardware fitted inside to support wireless charging.


Since Electric vehicles also use lithium-ion batteries similar to smartphones and tablets, the same technology i.e. inductive charging, can be used to charge batteries of the Electric vehicles. The difference is that it will be performed on a larger scale while charging the Electric Vehicles. In inductive charging, electricity is transferred through an air gap from one magnetic coil in the charger to another magnetic coil fitted in the battery of an Electric Vehicle. It works like this: A magnetic loop antenna (copper coil in the charger) is used to create an oscillating magnetic field, creating a current in one or more receiver antennas (electricity receiving apparatus in Electric vehicles). If the appropriate capacitance is added so that the loops resonate at the same frequency, the amount of induced current in the receivers increases. This is resonant inductive charging or magnetic resonance; it enables power transmission at greater distances between transmitter and receiver and increases efficiency. Coil size also affects the distance of power transfer. The bigger the coil, or the more coils there are, the greater the distance a charge can travel. To ensure both coils are aligned, all you have to do is park the vehicle in the right place, and then charging can begin. As every coin has two sides, the newly developed technology, i.e. wireless charging system for Electric vehicles, also has its merits and demerits.


Merits of Wireless Charging

  • A convenient way of charging when electric contacts are not available, or batteries are embedded in the product.

  • Reduce the need for separate charging adapters used by different companies.

  • A faster rate of charging.

  • Distance between the coils for wireless charging can be increased from 5 mm to 35mm.

Demerits of Wireless Charging

  • Since wireless charging technology is still in the developing stage, the performance of conventional wired charges is much more reliable than wireless charging at this point in time. But with the evolving technology, the performance of wireless charging technology will be at par with conventional wired charging.

  • For wireless charging to act, the user can put the Electric vehicle in a specified position over the charging pad. Thus, exhibiting mobility issues.

  • Compatibility of Electric vehicles from different manufacturers towards a wireless charging station.

  • More expensive.

Standards For Electric Vehicle Wireless Charging


Standards refer to the different set operating systems with which devices are compatible. There are two main standards, i.e. Qi and PMA (Power Matters Alliance). These two standards work very similarly, but they use different transmission frequencies and connection protocols. Because of this, devices compatible with one standard are not necessarily consistent with the other standard. However, there are devices compatible with both standards. Apart from these following are the standards used in wireless charging of Electric vehicles: -

  • Magne Charge, also known as J1773 is a largely obsolete inductive charging system used to charge battery electric vehicles made by General Motor.

  • SAE J2954 is an emerging standard and game-changer standard that allows Electric vehicles to be charged wirelessly using charging pads with power deliverable up to 11kW.

  • Qi is actually an interface standard developed by Wireless Power Consortium for wireless inductive electrical power transfer.

  • AirFuel Alliance: In January 2012, the IEEE announced the initiation of the Power Matters Alliance (PMA) under the IEEE Standards Association (IEEE-SA) Industry Connections. The alliance is formed to publish a set of standards for inductive power that are safe and energy-efficient and have smart power management. a. Rezence was an interface standard developed by the Alliance for Wireless Power (A4WP). b. Finally, A4WP and PMA merged into the AirFuel Alliance in 2015.

Patent Trend of Wireless Battery Charging for EV

The last ten years have seen a dynamic change in the patent trends in the wireless battery charging for electric vehicles. With humble registration of just 21 in the first year, the patent applications grew by almost 100 per cent in the following year, totaling 43. The third year saw a dip where the recorded patents were just around 28, much less than the previous year. The fourth year saw a gradual rise, followed by the fifth, where the records showed 42 and 64 patent applications, respectively. The sixth year recorded 74 patents, while in the seventh year, the number of patents showed a spike, and the count went to 116. The following year witnessed a drop in the number of patents where the number was close to 92. The ninth and the tenth year recorded 110 and 92 patent records showing the dynamism in its nature.


Conclusion


Electric vehicles as of now may have penetrated the passenger car market, but they are yet to make a dent in the trucks, vans, buses, and other vehicular markets. Also, electric-powered autonomous vehicles are yet to be appropriately introduced in the market. In order to do so, proper infrastructure and reliable technology are needed of the hour to make people go for electric vehicles rather than conventionally used internal combustion engine-based vehicles. Since 2010, annual sales of EVs in the United States have grown an astronomical 19,302.85%, from only 1,191 vehicles sold in 2010 to 231,088 in 2020, according to the Global EV Data Explorer. These numbers are enough to show that the emerging technology in the wireless charging domain and other aspects of Electric vehicles, such as performance, compatibility, etc., is trustworthy and reliable. Therefore, I can think of the near future, where electric vehicles will completely dominate the automobile industry and be as reliable as fuel-based vehicles are now.


References

  1. https://www.treehugger.com/how-many-electric-cars-are-on-the-road-in-the-us-5192754

  2. https://www.greencarreports.com/news/1130055_wireless-ev-charging-gets-a-boost-single-standard-will-harmonize-systems-up-to-11-kw

  3. https://www.techradar.com/news/wireless-electric-vehicle-charging

  4. https://www.epectec.com/batteries/wireless-charging-technologies.html

  5. https://www.prizminstitute.com/blog/advantages-and-disadvantages-of-wireless-phone-charging/

  6. https://www.sae.org/news/2020/10/new-sae-wireless-charging-standard-is-ev-game-changer