04/07/2024
History of wireless charging
In 1890, physicist and electrical engineer Nikola Tesla had already conducted tests on wireless power transmission. The International System of Magnetic Induction Units is also named after him. Tesla's method of wireless power transmission uses the earth as an inner conductor and the earth's ionosphere as an outer conductor. By amplifying the transmitter in a radial electromagnetic wave oscillation mode, a low-frequency resonance of about 8 Hz is established between the earth and the ionosphere. Energy is transmitted using surface electromagnetic waves that surround the earth. However, due to lack of financial resources, Tesla's bold vision was not realized. Although the feasibility of such a solution has been fully confirmed in theory by later generations, the world has not yet achieved unity, and it is impossible to achieve energy broadcasting and free access on a global scale. Thus, a great scientific idea was born.
On June 7, 2007, the MIT research team published its research results on the website of the American Science magazine. The research team successfully applied resonance to the transmission of electromagnetic waves and successfully "captured" electromagnetic waves. A copper coil was used as an electromagnetic resonance device, one coil was connected to the transmitting power side, and the other coil was connected to the receiving power side. After the transmitter emits electromagnetic waves of a specific frequency, the electromagnetic field spreads to the receiver, and the electrical energy is transmitted wirelessly. This technology, which they call "wireless power supply", has been successfully powered by a 60-watt light bulb two meters away after many tests. The longest transmission distance of this technology can only reach 2.7 meters, but researchers believe that the power supply can already charge the battery within this range. And only one power supply needs to be installed to power all the appliances in the house.
In February 2014, computer manufacturer Dell joined the A4WP camp. At that time, executives of the relevant camp said that they would upgrade the technology to support Dell and other computer manufacturers to wirelessly charge ultrabooks. Most traditional laptops on the market are powered by more than 50 watts, but ultrabooks use Intel's low-power processors and will become the first laptops to use wireless charging. Before this, wireless charging technology has always been related to "small" mobile devices such as smartphones and small-sized tablets. However, A4WP ("Alliance for Wireless Power"), one of the three major wireless charging camps, recently announced that its technical standards have been upgraded to support charging power up to 50 watts, which means that high-power devices such as laptops and tablets can also be wirelessly charged.
In October 2017, the family of mobile phones that support wireless charging welcomed three new members: iPhone 8, iPhone 8 Plus and iPhone X. They all support the Qi wireless charging standard. The purpose is to bring more convenience to users and make the phone itself look cooler.
