Google has been trialling two wireless-charging systems for self-driving cars at its headquarters and at a former military base where it experiments with vehicles.
The filings indicate that Google is testing the technology at its Mountain View headquarters and at the Castle Commerce Center in California, an ex-US Air Force base where Google tests its vehicles without the aid of a driver, as opposed to its public road tests, which always have a driver at the wheel.
As more electronic vehicles hit the roads, traditional charging stations pose a potential bottleneck, particularly in densely-populated parts of the world.
But as IEEE Spectrum also points out, wireless charging could help meet the needs of tomorrow's passengers once Google's autonomous vehicles arrive for the masses.
For example, Google's director of its self-driving car program, Chris Urmson, envisages its vehicles could provide transport for people with health conditions that otherwise prevent them from driving, such as vision problems or multiple sclerosis.
Those people, as well as passengers in a driverless taxi service, can't be expected to hop out of a vehicle and plug in a cord, Omer Onar, a researcher at Oak Ridge National Laboratory which focuses on wireless-charging systems, told the publication.
The systems from both companies use "resonant magnetic induction" to beam power from a grid-connected pad in the ground to the underside of a vehicle.
As Onar has previously outlined, wireless charging could take place while the vehicle is stationary, for example, at a garage or bus stop.
Alternatively, a dynamic system consisting of transmitters built into the road could charge vehicles while they are on the move.
The UK last year ran a project to explore the viability of dynamic wireless-charging systems embedded in highways. One of its chief goals was to militate against electronic vehicles running out of power on a highway.
As Momentum CEO Andy Daga has argued in the past, wireless charging could also increase the appeal of electronic vehicles by making recharging a superior experience to refuelling with petrol.