This Lab Just Set a New Record for Wireless EV Charging

• Oak Ridge National Laboratory used a Porsche Taycan for the test, designing the most lightweight charging system in the world per kilowatt.

• Inductive charging has shown promise in the past, but in the EV aftermarket its energy delivery rates are still very limited.

• The potential for consumer ownership of such a system appears rather modest because most EV owners will not have a suitable grid connection at their house.
  

A decade ago wireless or inductive charging for EVs was seen as a technology that would be very common in the real world in the 2020s. All owners would have to do to charge their cars at home or at work would be to pull into a parking spot with a small, flat mat, which would charge the EV battery without making contact.

Now, in 2024, cars certainly have wireless chargers, but they're for our phones, which require much less energy.

Wireless charging never quite took off on the scale that was predicted, even though inductive charging pads are certainly available in the EV aftermarket. And the major culprit, it seems, are still charging speeds.

If EV owners were going to spend serious money on a charging solution for the home, it might as well be a cord that would juice up the car as fast as possible, as convenient and futuristic as an inductive charging system might seem at first blush. Then there's also the factor of hardware installation on the car itself, which adds cost and weight.

Similar priorities have guided EV station development, along with a lack of common hardware in cars that would permit every EV on the road to use a charging mat.

But the charging speed aspect is showing signs of finally catching up.

Recently, scientists at Oak Ridge National Laboratory in Tennessee conducted the first wireless power transfer to a Porsche Taycan, using a polyphase wireless charging system at 270 kW. The breakthrough was reached just months after the same system achieved a 100-kW wireless charging session.

The team at Oak Ridge used lightweight polyphase electromagnetic coupling coils, featuring a relatively compact diameter of 19 inches. The laboratory said this method of power transfer is similar to that used to charge phones, but the crucial factors are the design and unique geometry of the polyphase coils. Another important factor was the compact size of the charging system on the undercarriage of the Taycan.

The result, according to Oak Ridge, is the most lightweight charging system in the world per kilowatt.

"The receiver coil designed for the Porsche Taycan research vehicle can achieve 8 to 10 times higher power density compared to existing systems," noted Omer Onar, leader of the Vehicle Power Electronics group and lead researcher on the Porsche demonstration at ORNL.

The next step is developing the system into something that can be manufactured easily and cost effectively.

The potential for consumer ownership of such a system, however, appears rather modest for one major reason: Most EV owners will not have a suitable grid connection at their house that can channel 270 kW into their car's battery.

Such hardware would be prohibitively expensive even for a corded charger, to put it mildly. In fact, not even all DC fast-charging stalls at an EV station of your choice will offer you 270 kW via a cable on any given day.

In practical terms, such a system would also have to become very common as a hardware format in EVs to be offered at fast-charging stations, to the point where real-world users could take advantage of its convenience. And as we have seen with the charger format wars, agreeing on a truly common plug standard has taken well over a decade and is far from being settled.

If there is a competitor to polyphase systems, it is likely to still be DC fast-charging, with battery swap stations in a distant second place. The increase in corded DC charging speeds at stations (now approaching megawatt-level for trucks), along with the proliferation of 800-volt architectures in cars, appears to still favor corded charging stalls.

Will inductive charging take off in the coming years as it approaches DC fast-charging speeds, or will the demands of this technology remain too niche? Let us know what you think in the comments below.