What Is a Wireless Charging and Monitoring Device?
A wireless charging and monitoring device is equipment that charges various devices (provides power) and monitors the charging status and battery condition without the need for wired connections through metal contacts such as terminal connections.
Wireless charging is used in a wide range of applications, from personal devices like smartphones and wearable devices to industrial equipment such as sensors, AGVs (automated guided vehicles), collaborative robots, and automated transport carts. The advantages include eliminating the need to plug and unplug power cables, reducing issues related to cable breakage, and avoiding connector wear and tear. In industrial applications, the absence of metal contacts also eliminates the risk of electric shock, greatly enhancing safety.
Uses of Wireless Charging and Monitoring Devices
Wireless charging and monitoring devices are used for wireless charging of various devices, both residential and industrial. Major applications include:
- Smartphones
- Wearable devices
- Industrial sensors such as temperature and pressure sensors
- AGVs (automated guided vehicles) and automated transport carts
- Industrial robots like collaborative robots
In particular, introducing wireless charging to AGVs allows automatic charging during downtime when the AGV is stopped for loading and unloading tasks, thereby efficiently utilizing standby time. The lack of metal contacts also removes the risk of accidents due to sparks or electric shocks, and reduces labor costs associated with charging tasks, thereby contributing to increased productivity.
Principle of Wireless Charging and Monitoring Devices
Overview
Wireless power transfer methods are broadly classified into two types: “radiative” and “coupling (non-radiative).”
“Radiative” methods use light such as laser beams or radio waves such as microwaves. These are suitable for long-distance power transmission but are currently limited to research stages due to significant energy loss and poor transmission efficiency.
“Coupling” methods efficiently transfer power over short distances and are the types currently being implemented. Coupling methods can be further divided into systems using magnetic fields and those using electric fields as the medium for power transfer.
Electromagnetic Induction Method
The electromagnetic induction method generates charging by creating an induced magnetic flux between the transmitting and receiving sides. When two coils are brought close together and an electric current flows through one coil, an electromotive force is generated in the other coil via the magnetic flux passing through the coils. This method is one of the most common for wireless charging due to its compact size and low cost.
However, the transmission distance is short, and charging cannot occur if there is misalignment between the transmitting and receiving sides.
Magnetic Resonance Method
The magnetic resonance method generates power for charging by resonating the magnetic field resonators of the transmitting and receiving sides. This method allows charging over longer distances compared to the electromagnetic induction method, and can transfer power over several meters. It is mainly being researched for charging electric vehicles.
Electric Field Coupling Method
The electric field coupling method uses electrodes placed facing each other between the transmitting and receiving sides. This forms a capacitor, and when high-frequency electricity flows through one side, electricity also flows through the electrode on the other side. This phenomenon is utilized for charging in the electric field coupling method.
While the transmission distance is short, similar to the electromagnetic induction method, this method is less affected by misalignment.
Types of Wireless Charging and Monitoring Devices
Various products are available for wireless charging and monitoring devices.
By application, there are charging devices for small devices like smartphones, equipment for transport vehicles like AGVs, and devices for industrial sensors. Additionally, wireless charging systems for electric vehicles are being developed, with demonstration tests being conducted for systems that transfer power non-contactly from ground-installed transmitting coils to receiving coils in EVs.
Wireless charging devices for industrial sensors may include features that allow real-time monitoring of temperature, pressure, signal power rate, sensor name, and charging level simultaneously with charging. Some products also come with waterproof and dustproof structures.