Modern wireless charging technology revealed (Photo 2)

The revolution started with mobile phones

　　After the promotion of wireless charging technology, people only need one charger to charge all their devices. Moreover, with the continuous promotion of this technology, wireless charging transmitters can be easily found in every place where we live, work, and even in cars, airplanes, hotels, and offices. This means that people no longer need to carry any wires with them and can charge their appliances anytime and anywhere. At the end of this year or the beginning of next year, the wireless charging receiver will be fully "slimmed down" and become a wireless charging receiving chip built into mobile phone products, which is only the size of a fingernail. At present, many internationally renowned mobile phone manufacturers support this technology, and wireless chargers may also be bundled with mobile phones for sale.

　　Menno Treffers, chairman of the Wireless Power Consortium, said that the Qi wireless charging standard uses electromagnetic induction technology, which is more efficient.

　　Mobile phones will have built-in charging receivers and unified wireless charging standards

　　To realize wireless charging of mobile phones and other products, there must be two parts: a transmitter, which is connected to the power supply and is responsible for transmitting electrical energy to a wide space; and a receiver, which is generally installed on electronic products to receive electrical energy. At present, wireless charging technology has begun to be used in mobile phone products. Take the iPhone as an example. Now wireless charging manufacturers have modified it to enable it to have wireless charging function, and installed a kind of "clothing" similar to "apple skin". As a wireless charging receiver, it currently appears in the form of adding a mobile phone charging shell, but related modified products may be launched in China this year. At present, this shell is called "Qi door", which supports iPhone and BlackBerry mobile phones. Users can experience this function first without changing their mobile phones. At the end of this year or the beginning of next year, the wireless charging receiver will be fully "slimmed down" and become a wireless charging receiving chip built into mobile phone products, which is only as big as a fingernail. At present, many internationally renowned mobile phone manufacturers such as Nokia, Philips, LG, Samsung, Sony Ericsson and RIM are very supportive of this technology, and wireless chargers may also be bundled with mobile phones for sale.

　　The key to wireless charging for mobile phones is compatibility. The Qi standard ensures brand compatibility

　　Wireless charging technology mainly uses electromagnetic technology to convert electric current into electromagnetic in the transmitter, and the mobile phone converts electromagnetic into electric current through the built-in chip receiver to charge the mobile phone. The key to the promotion of wireless charging technology is to ensure that wireless chargers of various manufacturers are compatible. The formulation of the Qi standard has unified technical specifications for wireless charging, ensuring the compatibility of the same charger with multiple brands and multiple products. Menno Treffers, chairman of the Wireless Charging Alliance, said that the Qi wireless charging standard uses electromagnetic induction technology, which is more efficient and safer than other technologies. The Qi wireless charging standard includes three aspects: interface, performance and regulations. This will be a considerable challenge to the popularization of wireless charging technology. Therefore, mobile phones that pass the Qi standard will be able to be wirelessly charged through any Qi-certified charging base station, base or other rechargeable device. Qi's first initial requirement for the device is that it must not exceed 5 watts, which may be a major limitation for some manufacturers who hope that laptops can also use wireless charging technology.

　　Some manufacturers have launched Qi standard wireless charging products, which are widely used in the market.

　　Energizer, the world's largest battery and portable lighting equipment manufacturer, recently announced that it will soon launch wireless chargers that support the Qi standard, and will first bring a new wireless charging experience to Apple iPhone 3GS and Blackberry Curve 8900 users. At the same time, data provided by market research company iSuppli shows that the wireless charging equipment market will reach a scale of 14 billion US dollars in 2013. It is reported that Philips has already started producing new mobile phones with wireless charging settings.

Wireless charging technology questions remain to be answered

　　Just like people are now concerned about whether Wi-Fi wireless signals and mobile phone antenna poles have interference and radiation and other side effects, people still have many safety questions about the newly emerged wireless charging technology, such as whether it will generate electromagnetic radiation? Will there be restrictions on use and concerns about increasing the price of digital products? Regarding the core safety issue, professionals believe that in theory, this system is completely harmless to people in the charging field, because the power is only transmitted between coils that resonate at the same frequency; although the power conversion rate of wireless chargers is not particularly high, with the gradual advancement of technology, I believe that one day it will catch up with direct chargers.

　　Regarding the safety of electromagnetic radiation from wireless charging technology, experts believe that it is harmless to the human body.

　　There is no authoritative answer to the impact of electromagnetic waves on human body radiation, and safety still needs to be solved step by step

　　When it comes to safety issues, the wireless charging system mainly includes two aspects. One is how to ensure that electromagnetic waves are only radiated to the receiving part of the mobile phone, without affecting human health or interfering with other devices; the other is to prevent electromagnetic radiation from damaging the battery and charger in the event of incorrect use, such as identifying foreign objects on the wireless charger and preventing the danger of deformation or explosion caused by overheating of the lithium battery. Experts said that all of this requires a lot of software and hardware work to achieve. In terms of market development, it still needs to be gradually transitioned in stages, and there are still many problems to be solved.

　　Wireless charging has a small coverage area and its power conversion rate is 30% lower than direct charging.

　　At present, wireless chargers cannot achieve the same wide coverage as wireless networks. Although the charging plate and the receiver are two parts, they cannot be separated too far from each other, otherwise the charging efficiency will drop significantly or even fail to charge. In addition, the conversion rate of wireless chargers is much lower than that of wired chargers, and the current maximum can only reach 70%. But this is already a very good effect. Therefore, although it may not be widely popularized at this stage, wireless chargers will become a new development direction. Although the magnetic resonance method is good in theory, it still encounters many troubles in actual design. Not only parasitic capacitance and external magnetic fields, but even connected receiving devices can interfere with the charging electromagnetic field, thereby affecting the charging efficiency. In addition, the smaller the device, the more it will be affected by external factors, making this technology difficult to apply to mobile phones. Wireless charging technology can currently only charge small appliances within a range of 2 meters. Researchers hope to increase the effective charging distance to 30 meters.

　　Wireless charging technology has been used in professional fields where the airtightness of products needs to be guaranteed, such as underwater equipment, in-vivo medical devices, etc. However, facing the huge consumer equipment market, it is still unknown whether this technology, which is in its infancy, can convince people to "get rid of the last cable". However, wireless charging technology is still rated by foreign media as one of the most anticipated high-tech in the 21st century. Its creativity has indeed brought convenience to human life. We believe that technological progress will make wireless charging increasingly mature and have a broader space.