UK Researchers Explore Wireless Charging in EVs
06-01-2021 | By Robin Mitchell
Recently, a research project conducted by Western Power Distribution is looking to determine wireless charging viability in EVs. What is wireless charging, what advantages could EVs gain from wireless charging, and what disadvantages does wireless charging provide?
Western Power Distribution Looks into Wireless EV Charging
Recently, a research project conducted by Western Power Distribution is looking to determine the viability of wireless charging in EVs with backing from Toyota and Coventry City Council. According to the research group, one of the biggest challenges with EVs' battery charging mechanisms is the need for compatible chargers that can deliver increasingly larger current and voltage for faster charging.
The design being explored is a charging pad that sits underneath the vehicle (potentially embedded into the asphalt of the road), and a receiver pad fixed onto the vehicle's underside. When the two pads are in close proximity, the EV can be charged via induction (same action that drives transformers), and thus the need for a charging cable is removed.
The group has secured £417,000 of funding from themselves (WPD), and the energy regulator Ofgem. The research group will also explore if standard EVs can be retrofitted with such technology, thereby removing the need for old cars to be replaced with new ones supporting the wireless charging technology.
Advantages of Wireless EV Charging
The ability to charge an EV wirelessly presents several advantages not seen by standard cable charging methods.
The first major advantage is the lack of a charging cable, and an engineer involved with cables and connector designs knows the many problems they present. To start, connectors can wear down over time, thereby reducing their ability to work efficiently. Secondly, cables have to be chosen to handle the desired power rating, but if that power rating changes in the future, the cable may not be appropriately sized.
The next issue with using a charging cable is the need for a unified connector that all manufacturers can agree on. As technology progresses, more features may be needed from the charging cable, and making such changes may not be possible, thereby limiting the cable's capabilities.
A wireless charging system can be integrated into parking spaces, and garages where the EV will be stationary. From there, the EV can charge while unused, thus improving the range and practicality of EVs. If taken further, wireless charging pads on roads could charge EVs while driving, or when long traffic queues form.
Disadvantages of Wireless EV Charging
While the idea behind wireless charging may be an exciting opportunity to explore, it is more likely to be a novelty at best.
To start, wireless charging is rarely used due to the high inefficiencies involved. Charging cables allow for a near 100% energy transfer from the source to the battery, but a wireless charger can have efficiencies as low as 60%. Considering that a large proportion of electricity is generated from fossil fuels, this inefficiency would increase CO2 production.
The efficiency issue with wireless chargers is further compounded by the distance between the vehicle and the charging pad. Wireless chargers are most efficient when the distance between the two coils (transmitter and receiver) are as close to each other as possible. However, a charging pad on the floor and one on the car's base would see a significant separation.
While a wireless charger in a parking lot or garage is somewhat plausible, it is unlikely to ever work on main roads. Such a charger would need to be embedded into the road instead of raised; otherwise, it would effectively behave as a speed bump.
Wireless chargers, being a crude transformer, are also dependent on each coil's number of turns. Therefore, all manufacturers would have to conform to a specified coil size, turns, and power rating, which is the same issue that current manufacturers already face with charging cables.
Conclusion
It is important to research different ideas and avenues that could turn up interesting facts that were not known previously. However, it is unlikely that wireless EV chargers' research will bring about anything new due to the many flaws inherent in wireless charging.
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