1. The core wireless charging technology is not perfect; 2. It is difficult to realize long-distance transmission in the radiation area; 3. Long-distance positioning requires too much hardware; 4. The magnetic field * * * vibration height matching can be controlled very little; 5. The scope of application is limited and has not been expanded; 6. Market factors and consumer psychology make developers reluctant to vigorously carry out technology research and development. Researchers at the Massachusetts Institute of Technology said that the human body has a strong response to the electric field, but the human body has a small response to the magnetic field, so this system will not affect human health. However, this is only a speculation, and some researchers are worried about this view, and further experiments are needed before it is really applied to life.

As an electronic charging product, the charger itself cannot avoid radiation, so it is inevitable that the wireless charger will have radiation. However, the power of the wireless charger is very small, the charging time is long, and the radiation generated is small, so it should not cause great harm to people. In order to avoid unnecessary waste and produce more electronic waste, China is implementing the unified standardization of mobile phone charger ports. But for wireless charging technology, it will be popularized to the greatest extent: not only mobile phones can be used, but also digital cameras, iPhone, iPad and notebooks can share this charging device together. Fujitsu of Japan is even preparing to introduce a more advanced technology to extend this success from portable electronic products to electric vehicle charging. The ultimate goal of Fujitsu's move is to set up a public "charging point" on the street, which can provide more convenient 24-hour all-weather charging service for users of portable digital devices and electric vehicles. In addition, wireless chargers are smarter and more energy-efficient. Although the efficiency of wireless charging equipment is about 70%, which is equivalent to wired charging equipment, it has the function of automatic shutdown when fully charged, thus avoiding unnecessary energy consumption. And this efficiency reception rate is also constantly improving.

The mobile phone will have a built-in charging receiver and a unified wireless charging standard.

To realize wireless charging of mobile phones and other products, there must be two parts: the transmitter, which is connected with the power supply and is responsible for emitting electric energy to a vast space; Receivers are usually installed on electronic products to receive electric energy. Wireless charging technology has been used in mobile phone products. Take iPhone as an example, in order to make it have wireless charging function, wireless charging manufacturers modified it and installed a kind of "clothes" similar to "apple skin". As a wireless charging receiver, it appears in the form of adding a mobile phone charging sleeve, but it may launch a related transformation product China. This shell is called "Qi Gate" and supports iPhone and BlackBerry, so users can experience this function first without changing their mobile phones. At the beginning of 20 13, the wireless charging receiver will be completely slimmed down and become a built-in wireless charging receiver chip in mobile phone products, only the size of a fingernail. Nokia, Philips, LG, Samsung, Sony Ericsson, iPhone, HTC, Google, ZTE, Sharp, RIM and many other internationally renowned mobile phone manufacturers are very supportive of this technology, and wireless chargers may also be bundled with mobile phones.

The key to wireless charging of mobile phones lies in compatibility, and Qi standard can ensure brand compatibility.

Wireless charging technology mainly uses electromagnetic technology to convert current into electromagnetic at the transmitter, and the mobile phone charges the mobile phone by converting electromagnetic into current through the built-in chip receiver. The key to the popularization of wireless charging technology is to ensure the compatibility of wireless chargers from various manufacturers. The establishment of Qi standard makes wireless charging have a unified technical specification, which ensures the compatibility of the same charger with multiple brands and products. Menno Treffers, chairman of the wireless power consortium, said that Qi's wireless charging standard adopts electromagnetic induction technology, which is more efficient and safer than other technologies. Qi wireless charging standard includes interface, performance and regulations, which will be a considerable challenge to the popularization of wireless charging technology. Therefore, a mobile phone that has passed the Qi standard will be able to charge wirelessly through any charging base station, cradle or other rechargeable equipment that has passed the Qi certification. Qi's first requirement for equipment is not higher than 5 watts, which may be a big restriction for some manufacturers who hope that laptops can also pass wireless charging technology.

Some manufacturers have introduced wireless charging products with Qi standard, which has a broad market.

Energizer, the world's largest manufacturer of batteries and portable lighting equipment, said that it will soon launch a wireless charger product supporting Qi standard, which will first bring a new experience of wireless charging to users of Apple iPhone3GS and BlackBerry Curve 8900. At the same time, the data provided by market research company iSuppli shows that the wireless charging equipment market will reach the scale of 654.38+04 billion US dollars in 2065.438+03. Philips has started to produce new mobile phones with wireless charging settings. Philips X723 mobile phone has appeared, with 3.2-inch 240X400 screen, GPS and 3-megapixel camera. Fortunately, the machine will be equipped with wireless charger Xenium Q 1(Qi wireless power alliance standard) as standard, but the specific time and price to market have not been disclosed yet. Although this paper focuses on the charger, it also briefly introduces the receiving antenna. Because this wireless charging device is essentially a transformer, the primary is installed in the charger and the secondary is installed in the terminal.

Because the receiving antenna that is not matched with the charger will cause the current fluctuation of the charging circuit, how to choose a good charging antenna?

First, the terminal antenna should be magnetically shielded.

If the charging antenna is just a hollow coil, when a nearby metal object approaches, it will produce eddy current, which will reduce the charging efficiency, prevent the charger from radiating energy, increase the current and make the charger heat up.

Second, the magnetic media used by the charger are divided into two categories: organic magnetic materials and inorganic magnetic materials.

Organic magnetic materials can be made very thin and warped, which is suitable for the back cover of mobile phones and used in mobile phones; The inorganic magnetic material is made of sintered ferrite, which is fragile and suitable for large space installation.