Most of the GM and other EV models we see on the road use some magnets in the motors and the function of the vehicle. A magnet is needed to create a field that produces the energy needed to drive the vehicle wherever we need to go. Until recently, magnets were expected to be of a permanent length, which means only a single potential output. Because range has been a key factor in the development of EV models, these magnets have been small to help offer enough energy to get the vehicle moving in a comfortable way, but protect the range offered from the batteries.
While some Silicon Valley tech companies view GM as a dinosaur company from Detroit and one that’s stuck in the history of the internal combustion gasoline engine, GM has been part of the EV market for several decades. This company dates back to the 1960s with the Electro-Vair and Electro-Maro programs that were followed up by a battery-powered Chevette in 1977 which then led to the production of the EV1 in the late 1990s. Even though there wasn’t a continued focus on EV driving throughout the years, GM has been part of the technology longer than most other companies.
What is GM Proposing?
Recently, GM filed a patent for an electric motor that could benefit from multiple magnet lengths rather than a single length. This could be the future of the EV market because one motor could be used across a line of vehicles with a range of performance numbers based upon the different magnet lengths that are used. Currently, with a permanent magnet installed in a motor, each motor has to be built differently with different magnets installed to give the performance numbers desired, which can be a production problem.
In order to see this better, consider the Chevrolet Bolt which uses a permanent magnet brushless motor. The magnetic field is produced by spinning the magnet and rotor assembly which transfers to the stator core and interacts with the flowing current to create torque. Different magnet lengths could change the torque output with smaller ones decreasing the number while longer magnets increasing the torque. The idea is to use a new modular sheet which could accept multiple different magnet lengths with tabs within the system that can be layered to be the magnet slots.
These layered tabs will accept either short or long magnets with shorter ones being supported halfway down the aperture which would get pushed out of the way when a longer magnet is used. There could be as much as a 25 percent difference in the magnet lengths that are used in these vehicles. The difference in the magnet size could be a drain on the batteries and the technology hasn’t been perfected as of yet, but if GM can make this work, they would be able to use one motor assembly for their EV models across several different vehicles in the future and may be able to make a widespread application of this new system possible for our driving needs.