The recent move towards green energy is making the transportation sector fast adopt electric vehicles. EV’s zero tailpipe emissions are great for reducing your carbon footprint; however, the traditional lengthy charging process can significantly affect its overall convenience and adoption rate.
That said, wireless charging technologies, due to their capability to streamline the charging process of EV’s lithium-ion batteries, are fast gaining momentum.
In this article, we will dig through different wireless charging technologies for lithium-ion EV batteries.
How Wireless Charging Technologies for Lithium-ion EV Batteries Work?
Wireless charging allows operators to charge EVs without plugging them into a cable.
It comprises two main components:
- The Ground Unit (Charging Pad): Installed in the ground, the charging pad contains a range of magnetic coils. Needless to mention, these coils generate an electromagnetic field.
- The Onboard Unit (Vehicle Receiver): Placed in the underpart of an EV, the onboard unit comprises coils where the induced AC magnetic field generates AC.
Let’s go through its operating principle.
Wireless charging operates based on the theory of inductive charging. In this process, an AC is passed through a coil (transmitter) placed inside a charging pad. The electric current generates an oscillating magnetic field around the coil. The changing (AC) magnetic field, through electromagnetic induction, generates an induced current in the receiver coil when it’s parked on the transmitter. This induced AC goes through a rectifier, which converts it to DC. The DC then charges the EV’s lithium-ion battery. The charging process is done through a battery management system (BMS). The medium here is the vacuum (air).
The transmitter is installed in a road lane or parking lot, whereas the receiver can be found on the underpart of the EV.
Factors like coil size, coil alignment, AC amplitude, and frequency greatly affect the power transfer and efficiency of the wireless charging system.
To optimize these factors, wireless charging systems use compensation networks on both sides of the air gap. These networks have capacitors and inductors to adjust the coils’ impedance and resonance.
Benefits of Wireless Charging for EV Batteries
- Convenience: With a wireless charging system, you don’t need to use cables; meaning, now you have a more convenient way to charge your vehicle.
- Reduced Infrastructure: With wireless charging technology fast gaining momentum, there has been a significant reduction in the need for cables and wires. This approach to charging Lithium-ion batteries of EVs is not only more efficient and streamlined than traditional wired charging systems but also reduces physical infrastructures such as charging stations.
- Efficiency: Automated and wireless charging technology, when the receiver is in alignment with the transmitter, can ensure minimum energy loss, leading to a more efficient charging process.
- Safety: No involvement of wires and cables makes the EV charging system safer compared to traditional wired charging systems.
Challenges with Wireless Charging System for EVs
- Cost: Implementing wireless charging infrastructure is a matter of hefty investment that can cause setbacks in its adoption.
- Standardisation: Creating common protocols to manage power transmission and reception in EVs is crucial for wireless charging systems.
- Charging Speed: Innovations and advancements have revolutionised the wireless charging system; however, it still lags behind the traditional wired charging system when it comes to power transfer.
Current and Future Development in EV Battery Wireless Charging
Research is going on to devise and harmonise different standards and protocols available on EVs. Organisations including the Society of Automotive Engineers (SAE), the International Electrotechnical Commission (IEC), the International Organization for Standardization (ISO), and the Wireless Power Consortium (WPC) are actively engaged in developing a universal framework to ensure wireless charging systems are effective and safe across various EVs.
Concurrently, the increasing demand for EVs is driving the manufacture of wireless chargers for EVs. Companies like WiTricity, Qualcomm, and Evatran are making various types of chargers, from stationary to movable, and from low to high power.
In addition, to ensure mass implementation of EVs, test projects are being rolled out in cities such as London, Seoul, and Berlin. Leading automakers like Toyota, Audi, and Nissan are making EVs that work with wireless charging. This helps advance and adopt wireless charging technology.
The Future of Wireless Charging
The ongoing advancements are expected to reshape wireless charging technology, enabling more efficient, adaptable, and standardised charging. Let’s go through what the future of wireless charging systems for EV batteries looks like:
- Increased Efficiency: Ongoing research on equipping wireless charging systems with high-end power management algorithms, enhanced power delivery systems, and the increased energy transfer rate is expected to make wireless charging technology as efficient as the wired charging process.
- Dynamic Charging Technologies: That day is not a long way off when the wireless charging system will be equipped with dynamic charging technologies and get charged while in movement. By extending driving ranges, optimising energy management, and enabling augmented driving experiences, dynamic charging technologies are expected to transform the way EVs are powered.
- Boosted Energy Efficiency: By limiting energy waste, and streamlining the charging process, wireless charging is predicted to help charge EV batteries faster and more efficiently. It can significantly reduce energy consumption by maximising energy use, thus curbing a significant volume of carbon dioxide from the charging process.
- Smart Grid Integration: Wireless charging systems will likely use smart grid tech for grid balancing, better energy distribution, and demand response. Thus, EV batteries can be scheduled for charging during the off-peak hours when the production of renewable energy is at its peak. This way, smart grid functionalities in wireless charging systems, by reducing the use of electricity for the grid, reduce carbon emissions of electricity production.
