Wireless charging gets rid of chargers and realizes unlimited possibilities

Have you ever had this experience: when you want to charge your camera, mobile phone or tablet, the charger is mixed up with the chargers of other electronic products, and the wires are tangled. These chargers look similar, not only are they ordinary "black" chargers, but they also accumulate dust over time. After a long time, even the chargers of those electronic devices that are not in use are not sure whether they can be discarded, or whether the connectors are worn out or have poor contact. This seemingly inconspicuous charger has not changed much in appearance in the past few years. Manufacturers have not paid too much attention to the design and packaging of the charger, and it has fallen to the fate of a supporting role. However, in recent years, in addition to the software and hardware improvements of electronic devices themselves, the industry has also paid attention to the details of these accessories, improving the bulky chargers and troublesome wires. With the development of wireless charging technology, it can also effectively abandon the messy and troublesome configurations of the past, helping users improve the convenience and ease of use of products.

Figure: Nokia Lumia 920 wireless charging diagram

In fact, wireless charging technology has been around for many years and is not a new technology that has been developed recently. In fact, the electric toothbrush used in a wet bathroom is an example of wireless charging in practice in life. Because of the wireless charging design, it can prevent the risk of short circuit or electric shock caused by encountering water.

There are several methods for transmitting power wirelessly. From the perspective of safety and technical maturity, magnetic induction and magnetic resonance are the two mainstream technologies that may become popular in the future. Here is a brief introduction to these two technologies:

Magnetic induction : The basic principle is to install a coil at both the sending and receiving ends. When the sending coil is connected to a power source, it forms an electromagnetic induction of "current generates magnetic energy, and magnetic energy creates current". The receiving coil senses this electromagnetic signal and generates electricity to charge the battery through changes in the magnetic field. However, the disadvantage of magnetic induction technology is that it has its physical limits. The charging distance cannot exceed 5 mm, and as the distance increases, the power loss will become very large. When charging through magnetic induction, electronic devices will have overheating problems, and there will be safety concerns for supporting high-power products.

Magnetic resonance : The principle of magnetic resonance is different from magnetic induction, which uses the mutual induction principle to exchange electromagnetic energy. Instead, it uses the resonance principle of the same frequency between the charging base and the object to be charged to efficiently transmit energy. When the sending end and the receiving end vibrate at the same frequency, the receiving end can receive the electromagnetic field generated by the sending end, and then receive the energy transmitted.

According to statistics from market research firm IHS iSuppli, in 2012, more than 5 million electronic devices were equipped with wireless charging functions, and it is predicted that the number will exceed 100 million in 2015. However, there is no common standard for wireless charging technology today, and each manufacturer hopes that its technology will become the mainstream in the market. Faced with the huge business opportunities generated by the gradual formation of the wireless power ecosystem, consumer electronics manufacturers, computer and automobile manufacturers have all registered patents related to wireless charging technology and formed different alliances to prepare for a battle for wireless charging standards.

Figure: Panasonic's wireless charging power bank

Products are charged everywhere, and stores discharge electricity everywhere

There are currently two alliances on the market that use magnetic induction technology, namely WPC (Wireless Power Consortium) and PMA (Power Matters Alliance). Another alliance, A4WP (Alliance for Wireless Power), uses magnetic resonance technology. Among them, WPC has the largest number of members and is the most active, with more than 130 manufacturers. The standard logo of WPC is "Qi". There are currently 140 products carrying the Qi trademark. In terms of smartphones, Nokia's Lumia 920 and HTC's Droid DNA are the most well-known. Currently, the next version of Qi specifications are being actively formulated, with the goal of allowing tablets to be wirelessly charged, so that the application of wireless charging can be more popular.

Duracell, a member of the PMA Alliance, also plans to spend hundreds of millions of dollars to build wireless charging equipment for Madison Square Garden and Delta Airlines lounges. Starbucks and McDonald's also plan to set up wireless charging pads in their stores to provide customers with the convenience of charging in the store, driving the growth of the wireless charging market. However, mobile phones equipped with wireless charging functions of different association standards cannot be charged across devices. And precisely because of the lack of a common standard, many manufacturers have not yet stated which technology they will invest in, which also causes consumers to worry about whether the products they purchase will be eliminated in the future.

According to Allion's senior technical testing team, both magnetic induction and magnetic resonance technologies are actively looking for more efficient charging methods. In the future, if we want to increase charging power and increase charging distance while improving charging efficiency, "magnetic resonance" technology seems to be a more feasible direction. Because wireless charging products using magnetic resonance are not limited by the distance of magnetic induction technology, and can support the function of charging more than two electronic products at the same time, it greatly saves consumers' space, budget costs and increases their willingness to buy. Therefore, magnetic resonance technology has a more promising future market.

Figure: HTC launches wireless charging version of Droid DNA in the United States

Medical applications have made great progress: devices embedded in the human body can also be wirelessly charged in the future

Wireless charging technology has become a feature of the new generation of smartphones. In addition, its convenience appeal has also won the favor of Intel, which announced that it will launch an Ultrabook with wireless charging function at the end of this year. Coincidentally, last year, researchers at Stanford University in the United States published a wirelessly charged human heart embedded device. This wirelessly driven micro-device similar to a pacemaker can be implanted on the surface of the heart, solving the problem of loading long-term power supply batteries and reducing the risk of surgery due to the need to replace batteries.

In general, wireless charging is a very practical function that allows users to charge electronic devices without wires or USB plugs. This technology can not only be applied to handheld electronic devices, but also to public facilities or electric vehicles through magnetic resonance technology, making wireless charging technology a reality in life. Magnetic resonance concentrates energy on the transmitter and receiver, which can effectively reduce unnecessary energy loss and can be expanded to the medium and high power markets, such as laptops, TVs, or electric car wireless charging devices. The commercial value of magnetic resonance wireless charging applications is promising, and associations and many large manufacturers are also developing it.

From the market perspective, because there is no unified standard specification, the development presents a multi-horse carriage situation. Consumers are not willing to buy because they are worried that the products they buy will be eliminated or will not be compatible with other products. Even if the products are certified by the same association, there will still be compatibility issues between each other. For example, after Qi certification, the sender and the receiver will have a protocol error during the interface communication, resulting in the phenomenon of being unable to charge. However, whether it is magnetic induction or magnetic resonance technology, we can predict that wireless charging technology will definitely be one of the mainstreams in the consumer market in the future. Therefore, it depends on the rise and fall of these three major standard associations and the support of telecommunications operators to determine the direction and future popularity of the wireless charging technology market. As an expert in the testing and verification industry, Allion will continue to track the technology and development of wireless charging and provide manufacturers with the most real-time information and market trends.