Wireless charging belongs to non-contact transmission
Wireless charging breaks the way that electric energy transmission can only rely on direct contact transmission of wires. It belongs to non-contact transmission and can avoid the problems of contact spark, sliding wear, explosion and electric shock that may be caused by contact electric energy transmission. There are three main modes of radio energy transmission: electromagnetic induction, electromagnetic resonance and electromagnetic radiation. Electromagnetic induction is the most commonly used radio energy transmission mode at present. Its technology has been mass produced, which is lower than other technologies in production cost, and has been verified by safety and shopping malls.
At present, there are three major alliances committed to the development and standard setting of wireless charging technology. These three alliances are Alliance for wireless power (a4wp), power matters Alliance (PAM) and Wireless Power Consortium (WPC). Qi standard is the "wireless charging" standard launched by WPC, which adopts the most mainstream electromagnetic induction charging technology.
Qi standard is mainly aimed at portable electronic products such as cameras, video and music players, toys, personal care and mobile phones. At present, the research and design of low-power wireless charger is mainly aimed at the wireless charging of mobile phone terminal, which is based on the bq500211 special chip of TI company, and the special integrated chip is also used in some low-power terminals. The use of special integrated chip can save development time in the initial development, but it is not conducive to cost reduction and later expansion and upgrading in the long run.
Although wireless charging technology has been developed to some extent, there are still some thorny technical problems in the development process.
First, the charging efficiency is not high. Once the distance is a little farther, the charging efficiency will be sharply reduced, and a lot of time and resources will be wasted to complete the charging, so it is of little significance.
Second, the safety problem in the charging process. High power wireless charging equipment will produce a large amount of electromagnetic radiation, which will not only have a certain adverse impact on health, but also interfere with aircraft and communication.
Third, practicality. The current wireless charging technology can only be realized by fixing it at a fixed point, which is inconvenient, so its practicability is not high.
Fourth, the price is expensive. Because the wireless charging technology is still in the preliminary research and application stage, the research cost is high, so the product price is also relatively high.