Faster than charging piles! Detailed explanation of fast wireless charging technology

    Imagine if you could sit in your car and complete the work that used to take 4-7 hours to plug in in less than an hour. Is that far-fetched? Actually not. Momentum Dynamics is quietly bringing this inductive charging technology to passenger cars and commercial vehicles.

Momentum Dynamics wireless charging prototype

    MD CEO Andy Daga revealed that almost all passenger and commercial vehicle manufacturers are actively promoting this technology. Obviously, electric vehicles that can be charged quickly are more practical. The CHAdeMO fast charger with a peak power of 50 kW adopted by Nissan Leaf can be fully charged in one hour (80% in half an hour), and the Tesla Model S with a larger battery can also be fully charged in less than two hours at its super charging station (official data peak power can reach 130 kW).

    MD's home wireless charging device can provide a peak power of 10 kilowatts (50A/240V) on the prototype. It does not require human operation at all, is safe and reliable, and the induced magnetic field generated by the current can "pass through" ice and even cement. The prototype installed in a public place has measured a peak power of up to 50 kilowatts. However, after many tests, the company believes that 25 kilowatts is the "optimal power" and sets it as the standard. According to such data, a home wireless charger can charge an electric vehicle with a range of less than 160 kilometers to 80% in half an hour, which is comparable to the current mainstream DC fast charging performance.

working principle

    MD's inductive wireless charging technology is actually very primitive, dating back to the days when Nikola Tesla was still alive. The technical means are nothing more than installing an induction coil on the ground and on the car, but the appearance must be designed to be practical and elegant enough. These coils that look like large donuts are not only very thin but also very efficient under the design of Bruce Long, vice president of MD.

    According to Daga, his charging system keeps the electromagnetic field within its application range and does not affect surrounding metal objects, such as metal parts on the car, which greatly improves its efficiency when charging at high power. "The entire system efficiency can reach 91% when charging continuously at 25 kilowatts," Daga said. "We can continue to improve the efficiency to 93% in the future. This efficiency is the power charged to the battery divided by the power of the wall socket."

Induction coil arranged on the chassis

    After five years of development, patent registration, and trial product testing, MD has successfully achieved charging without heating the surrounding metal, with a charging speed comparable to plug-in charging, and without much cost increase. This technology has also passed international electromagnetic pollution standards and is harmless to any animals. In order to achieve large-scale commercial popularization in the future, MD has also developed a solution to prevent interference between two vehicles charging side by side.

    "This is actually a form of near-field communication," Daga said. "It uses the electromagnetic field in wireless power transmission to transmit power and communicate information at the same time." The main problem this technology solves is the signal interference generated when multiple vehicles are charging at the same time. This vulnerability is very likely to provide a channel for hacker attacks. MD is also considering registering this technology as a patent. Including this technology, a number of "behind-the-scenes" technologies are the real magic weapon that allows MD to be at the forefront of wireless charging, not just fast charging speed.

    At least one mysterious automaker is evaluating MD's technology and may make it a supplier. Electric vehicles will be pre-configured with MD's wireless charging technology during the development phase and will be available to customers at dealers at any time. The retail product that MD is currently testing will be ready within a year. In the future, car owners only need to buy a receiver and put it in the car to use it at any time, just like the current Level 2 charger.

    MD may not be the first wireless charging company in the future, but the power of 5-10 kilowatts (adjusted according to the household power line) is still the fastest at present. Daga predicts that in the future, three-quarters of MD's products will be supplied to commercial vehicles and one-quarter to household cars, but the latter will gradually increase. In view of the current situation, Daga believes that every car company is betting on multiple technologies at the same time, but it is only a matter of time before wireless charging wins. So far, Tesla has not released any research on this technology, but other car companies, such as Toyota, are working with WiTricity, an important competitor of MD, which started at the Massachusetts Institute of Technology, to do related development. In fact, WiTricity's customers also include Nissan, BMW and Honda. Unlike MD, WiTricity's technology is more advanced and uses magnetic field resonance to transmit electricity. The energy transmitter and the energy receiver can exchange energy with each other by resonating at a specific frequency. One of its important advantages is that it does not need to be "docking in place" like MD's electromagnetic induction charging. At the same time, it also allows the transmitter and receiver to adopt different sizes, which increases the versatility and extensibility of the product. Especially for vehicle-mounted receivers, if the size can be reduced, then car manufacturers do not have to worry about the various troubles caused by vehicle weight distribution.

The development of electric vehicles is unstoppable

    Automatic charging is definitely a new growth point. For example, Volkswagen recently launched a sophisticated and complex automatic charging robot. This may be a Germanic engineering pride, but they are too complicated and too expensive. At the same time, car companies have actually been trying to get rid of charging cables and charging plugs from the beginning. There is no doubt that automatic charging robots do not meet this demand. The automotive industry is currently facing a dilemma with this technology: on the one hand, car companies, which have always been conservative, are often reluctant to move too fast; but on the other hand, they are also afraid that if some companies commercialize it in advance, car companies will have no way to go.

    Although many people are still on the sidelines about the development of electric vehicles, a recent Goldman Sachs research report titled "The Disruptive New Era of the Automotive Era" predicts that by 2025, a quarter of the world's vehicle models will be plug-in hybrid or pure electric vehicles. In other words, out of a total of 120 million vehicles, the volume of plug-in hybrid or pure electric vehicles will reach 30 million. At the same time, since the main driving force in this field currently comes from policies and regulations, Goldman Sachs also predicts that there will be a shift in the business model in the next decade, and new solutions for charging methods will inevitably emerge. "The automotive industry must open its arms to embrace technological change, and the urgency is far greater than ever before." Goldman Sachs said in the report.

    Another report from Morgan Stanley is more optimistic about the future, also based on policy forecasts. The report predicts that in ten years, one-quarter of new car sales in the US auto market will be electric drive products, compared with 1% today, this number is indeed very optimistic. Daga said that even if the reality is only a small fraction of this number, at least more and more electric vehicles will need to be charged.

Application Scenario

    In addition to building a few prototypes, Daga and his company also need to spend a lot of energy to promote their products into public places. Charging systems with a price of more than $10,000 are too expensive for most mall owners. Although they can take this opportunity to attract electric car owners to their stores, there will be many troubles. For example, some car owners will drive their cars to the charging points of these stores and "steal" electricity all day long. The Blink charging network plans to set up fines for such cheap behavior, but some stores remain neutral on this.

    Although its products are aimed at all kinds of users, MD's main business targets those stores that do not park all day, such as convenience stores, restaurants, large shopping malls, etc. It is very convenient for car owners to park for an hour or two and make up a long distance. At the same time, due to the characteristics of these locations, the phenomenon of occupying charging points all day will not occur.

    In addition, Daga predicts that in the future, charging will gradually shift from home charging to public charging. After all, in many places in China, South Korea, and even in Europe and the United States, not every household has a garage, and in many places no one actually has a garage. Therefore, Daga believes that wireless charging that can serve more electric vehicles will be more attractive. In China and other Asian countries, large-scale automatic parking lots are gradually emerging, and wireless charging meets their needs.

    "If an electric car with a range of 160-320 kilometers can be charged for 25-80 kilometers by simply stopping for a while, it will greatly extend the actual range of the vehicle," Daga said. "Compared to larger batteries, a more extensive charging network will give electric cars greater power."

    Regarding those who "steal electricity", Daga said: "We should not force people to change their lifestyles for cleaner transportation. We should encourage them to start changing." Daga himself is against fines for "stealing electricity". "Wireless charging allows people to switch to electric vehicles without changing their behavior. People drive, then park, and charge while parking so that they simply forget to charge, which will be more convenient than picking up a gas pump to refuel."

Summary: Where is the road ahead?

    MD's technology has a far greater application prospect than the electric vehicle industry, and has considerable potential in other fields such as medical devices. But its current focus is on electric vehicles, and Daga is confident in this field. He believes that the current number of gas stations can fully meet the needs of cars on the road, but because electric vehicles take longer to charge, more charging points should be deployed, which is also an important reason why he is optimistic about the prospects of MD.

    No one can predict what the future will be like, but it is foreseeable that wireless charging will gradually rise in the future and keep pace with the development of the global electric vehicle market. If everything goes as planned, MD will eliminate those annoying plugs and cables for us.