Inductive charging: how wireless battery charging works

 In Batteries

Imagine living in a safer world where the last cable has been unplugged as every electronic device works thanks to inductive charging:

  • you would be able to charge your smartphone, electric device or any appliance you have at home without plugging it in a charger and to put it wherever you like while it continues to be powered;
  • you would work in the most effective offices, with the most convenient configuration of the work space and integrated wireless interconnections between devices to easily share information;
  • you would live in spaces where everything, such as your car, the plane or the train you are traveling in, could become a wireless transmitter for the charging of your electronic devices.

We are not talking about science fiction

All this could become a reality very soon through the wireless battery charging, a technology that already exists.

This type of wireless recharge is actually not very recent because it has been around for a while: Oral-B electric toothbrush, for instance, has been using wireless technology since the 1990s, while the first mobile phones with the inductive charging were launched in 2009.

The reason why this type of technology is still not very well-established on the market is that, until recently, it wasn’t very efficient compared to traditional charging methods, even if the possibilities it offers are actually huge.

That’s why we want to offer you an in-depth analysis on how wireless battery charging technology works and show you why it has become so important these days.

What is the inductive charging and how does it work?

Inductive charging is based on the possibility of transferring power through the space between two objects, a transmitting source and a receiving device in order to charge or recharge a battery without any physical connection.

This technology works on the principle of magnetic resonance.

When electric power flows through the wires of an inductor – a loop of coiled wires around a bar magnet, it produces an electromagnetic field around the magnet which can be used to charge something which is nearby.

In order to receive this power, the charging station and the device to charge must be close, because the strength of electromagnetism decreases with distance.

Does the wireless power charge every object that is in the same place?

Inductive charging technology works only with objects which are supposed to be charged and not any other errant object which is in the same environment.

This is possible because the wireless charging stations use transmitters to communicate with small receivers which are placed in the devices to charge, such as a smart phone.

These devices can communicate thanks to Qi wireless charging technology. The Qi wireless standard was introduced in 2009 by Wireless Power Consortium.

It is a standard which allows using the same inductive charger to charge devices of different companies.

Why is this technology not established so far?

Even if this technology has been around for a long time, it has become mainstream only recently

This happened because in the past there wasn’t a way to efficiently transfer huge amounts of power through this technology: the amount and the strength of power transferred depends essentially on the number of coils looped around the bar magnet.

Wires and devices were also not small and cheap enough to make inductive charging competitive.

Today everything is easier because the costs have been reduced and technology is evolving.

Resonant wireless charging and inductive charging: same or different technologies?

Probably, regarding wireless power, you might have heard some people talking about inductive and resonant technology. They are often considered to be the same thing.

The reason is that Inductive power uses resonance principle to link the transmitter to the receiver coil: they are coupled when they oscillate, or better “resonate”, at the same frequency.

In recent time, however, something has changed and the word “resonant” gained a new significance.

Resonant Technology: what’s new today

Today the resonant wireless charging is considered as an evolution of the inductive charging as it offers some advantages:

  • has greater spatial freedom because you can place the device to charge where you like and you don’t have to align it with the transmitter;
  • charges many devices at a time;
  • improves the charging speed.

Wireless recharge: advantages and disadvantages

Wireless charging has many benefits, but it implies some disadvantages too.

The main pros of this technology are:

  • the wireless recharge is a safer technology because it doesn’t use any cable. It offers an easier charging experience because you have no cords to plug in and the charger has less chance of breaking. For example, It provides a safer experience if you have children at home who can stumble upon the electrical wires;
  • you have not to worry about different chargers for different devices because you have just one charging station to charge all your devices at the same time;
  • some wireless charging technologies can be integrated into any device size and shape, even in the smallest ones.

Regarding the disadvantages of wireless charging, the most important are:

  • wireless recharge can have a slower charge time and can be less efficient compared to a traditional charger;
  • even if the power is wireless, current technologies implies that the charging station are not portable because they need to be plugged into the wall;
  • you need a precise placement of the device in order to charge it properly;
  • there are some distance limitations because the transmitter and the receiver need to be placed at close range.

As you can see, all this disadvantages depend on the current technology: if new solutions can be developed for this technology, all these weaknesses could be reduced in the future.

An electronic development support could be the core of this process.

Besides charging the mobile phone: the future of wireless charging

Nowadays wireless charging technologies allow primarily to charge smartphones and smartwatches but what are the future scenarios?

Evolution of wireless technologies depends first of all on the characteristics of the battery of the future.

In last 150 years, the progress in the battery sector has not been significant, as modern batteries still have little power and high cost per Watt-hour, are still heavy and have a short life span.

Lately however something is starting to change, because recent batteries have a greater energy density, require less recharging time and consume less amount of power.

Moreover, researchers are still studying to develop faster recharge batteries, through nanotechnology.

If the battery technology improves, it may be possible to charge more power and bigger devices with important consequences on different market sectors.

Wireless charging and electric vehicles

Wireless recharge of electric vehicles is nowadays one of the most researched areas of evolution for wireless power.

At the moment vehicles’ batteries have limited capacity and can’t allow a vehicle to last as long as a petrol one, before requiring charging.

The charging process indeed requires access to a charging point, some charging cables and many hours before the vehicle is charged.

The wireless power would provide an easier charging experience because the vehicle could be charged even when it is parked or on the move.

Inductive charging and medical care

Wireless charging can be important in the future of medical care, too.

Nowadays, the most common medical procedures require medical equipment which is powered using battery packs and other forms of power supplies.

Inductive power would benefit this sector, returning a more sterile environment where traditional cables can be a source of contamination.

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