Breaking through the difficulty of long-distance charging, wireless charging is about to be invincible

2021-01-05 12:38:35 hongling

Breaking through the difficulty of long-distance charging, wireless charging is about to be invincible

Shenzhen mobile phone wireless charger manufacturer

   Electric vehicles, mobile devices and industrial applications are renewing attention to wireless charging technology.

    As we all know, electricity travels a long distance in the air, but without wires, it seems that there has never been a practical or reliable way to power electronic devices.

    In fact, wireless power supply has been around for many years. Whether wireless power supply can extend the life of the battery is not entirely clear. However, the processing capabilities and functions of terminal devices are increasing day by day. In contrast, battery capacity has been improved slowly, in order to alleviate the contradiction between the increasing functions and backward batteries, and to deal with the continued development of emerging markets such as electric vehicles and connected industrial applications. With growth, wireless charging has regained more attention.

    "I remember that 10 or 15 years ago, medical implants could be charged using a cuff or coil, so you don't have to go back for surgery." said Jeff Miller, product marketing manager of Siemens-Mentor. "Or when charging the tire pressure monitoring system on a truck, because there are no wires on the tires, wired charging is impossible, and you certainly don't want to remove the tires, so you must use a different method for charging."

    Most of the wireless charging application scenarios involve low-end consumer products such as industrial, automotive, or rechargeable electric toothbrushes, but now smart phones are increasingly integrated with wireless charging functions. Smart phones are mainly based on the Qi standard, which relies on the magnetic induction between the transmitter and the receiver to complete energy transmission. During the charging process, the transmitter and receiver need to be very close, basically they are almost in contact.

    In addition, people are still working hard to develop a solution that can complete mobile phone charging within a few feet away with the same charging time. In addition to charging the mobile phone, this solution may also use magnetic fields, ultrasonic waves, lasers or other devices at the same time. The radio frequency signal of this frequency charges many other devices, in addition to charging, it can even transmit media data.

    "The basic physics that does not transmit electricity through cables has been around for decades. The difficulty is not to transmit electricity through the air, but to be able to transmit electricity within a limited field strength range without interference, while reducing the cost. , Making it a popular product." said MennoTreffers, chairman of the Wireless Power Consortium (WPC). The goal of the alliance is to merge the previous two competing technical specifications into its Qi standard for near-field mobile phone charging.

    Treffers said it is very difficult for most wireless charging products to generate and actually provide the 5 watts or higher power required for charging smartphones.

    "It's easy to make a demo that looks like charging your phone 15 feet away. What really matters is the data," he said. "If you just transmit milliwatts of power to a device that requires 5W of power, it is basically useless. Using magnetic induction technology, you can get 5W of charging power, but some electrical appliances consume 2.4 kilowatts. The power consumption of drones and drones is also between 60 watts and 100 watts. Remote charging can help you realize the dream of never needing to recharge, but the ideal is very full, the reality is very skinny, we are far from solving higher The extent of the power wireless charging problem."

    Advantages of wireless charging

    According to a report released by IHSMarkit in February, consumers want to get rid of the inconvenience caused by charging plugs and help the shipment of consumer products supporting wireless charging in 2017 to increase by 40% to approximately 500 million units. By 2022, there will be 90 million smartphones equipped with wireless charging.

    2014 is the first year that smartphones are equipped with wireless charging functions. At that time, Starbucks installed a PowerMat charging board that adopted the PMA standard (now managed by AirFuelAlliance), and McDonald's installed chargers supporting the competitive Qi standard in its 50 stores in the UK. This also reflects the differentiation of wireless charging standards. Samsung and AT&T support PMA, and Philips, Qualcomm and Nokia support Qi of the Wireless Charging Alliance.


Apple’s decision to support the Qi standard for its new machine last year broke the balance of power between the two competing standards. This battle* ended in an agreement to integrate the two standards announced on January 8 this year. The IHSMarkit report predicts that the adoption of a unified wireless charging standard for Samsung and Apple mobile phones will encourage other mobile phone manufacturers to join in and further increase the number of users.

    Long distance charging

    Another big news comes from the FCC. Recently, it has certified two products that support long-distance wireless charging-one is 3 feet and the other is 80 feet. Currently, none of the commercial products that charge smart phone batteries exceeds a few inches.

    In December last year, the FCC certified a midfield transmitter called WattUp, which is a one-to-many charging unit based on radio frequency technology that can charge devices at a distance of three feet using 900MhZ and 5.8Ghz.

    It is also certified by Powermat’s 3-watt PowerSpot transmitter, which uses radio frequency technology and has a maximum charging distance of up to 80 feet. It uses 915MHz, which is usually reserved for ISM, and the frequency band can also be between 850 and 950MHz, which is a more typical frequency band for UHFRFID products.

    According to Victoria Fodale, who wrote this IHSMarkit report, numerous technical and regulatory issues make it difficult for us to estimate when we will see long-distance wireless charging commercial products.


Solis said: "The current long-distance wireless charging products have no commercial value, because they require too many trade-offs. Although it is not a perfect solution, but if you can continue to use the device within a few feet, even It’s just trickle charging to help slow down the consumption of battery power, which is also a very gratifying event."

    The energy level in wireless charging applications drops quickly, and it is difficult to maintain signal strength after a few feet. According to Teffer, this also requires increasing the power of the signal to such a high level that it would violate local broadcasting regulations and even safety regulations. It is difficult to find a good balance between power, safety and efficiency.

    Powercast's *Operation Officer and *Technical Officer Charles Greene said, "Mobile phones that support long-distance wireless charging are the holy grail of the industry." Powercast is the only two product that has recently obtained FCC approval to sell batteries that support 5 to 10 feet of long-distance charging of mobile phone batteries. One of the companies.

    "Physical properties do cause some limitations," Greene said. "As you get farther and farther away from the power source, the energy will gradually decrease. There are some ways to solve this problem, but these methods will narrow the charging range and make it more difficult to create an area where one-to-many charging is possible. This is what we Difficulties of concern."

    Powercast uses the Qi standard for charging smartphones, but it has not given up its own RF charging technology. Instead, it is developing a Qi-enabled mobile phone charger and integrating it into its own transmitter, which may be available in the third quarter of this year.

    Greene said: "The Qi standard is indeed very mature, but it also has its limitations. Usually, it is a one-to-one rather than one-to-many solution, and it requires a power board. We can provide other solutions equipped Through the transmitter on the desktop, we can provide the phone with 10% to 15% power overnight (from a distance), and we can further improve it to reach 50%, so that I can put This transmitter is placed on my bedside table or table. It can charge the phone continuously throughout the day, and maybe never need to plug in a wired charger."

    WiTricity’s CTOMorris Kesler said that wireless chargers can certainly achieve higher power than today, and at least achieve one-to-many charging within a short distance. WiTricity is a company that was incubated from the Massachusetts Institute of Technology in 2007 and aims to bring MIT professors Marin Soljačić’s research results are transformed into commercial magnetic resonance wireless transmission.

    WiTricity said it will provide rechargeable parking mats later this year, which will be sold as an accessory for high-end electric vehicles of a car manufacturer. Depending on the size of the car, the system can provide power from 3.6kw to 11kw with an efficiency of up to 93%. It can transmit power within a range of a few meters, allowing car owners to park normally instead of having to park the car a few centimeters away from the parking pad.

    "How far power can be transmitted depends on the size of the transmitter and receiver and your power level, but one of the advantages of magnetic resonance is the ability to make one-to-many connections," Kesler said. "The human body does not respond much to magnetic fields, so there is no need to worry about the effects of magnetic resonance on the human body. If you are trying to send energy in a room of about 10 meters, you may want to use an antenna to transmit the signal to a specific location."

    He said that there is no reason to think that mobile phones are the * wireless charging market. Although the electric vehicle (EV) market has just started, broadly speaking, many factories and warehouses have automated ground vehicles and industrial machinery. Almost anything that uses electricity and can move is a potential market for wireless charging, including medical applications. And implants.