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By Ben Coxworth
May 18, 2021
The dye normally fluoresces reddish-orange under ultraviolet light, but turns green when a telltale alcohol is present
Uni Halle / Alexander Funtan
Although some people may think that electric cars can run forever, their motors do wear out over time. According to a new study, special dyes could allow drivers and mechanics to know when that time is about to come.
Electric motors in automobiles and other devices contain tightly wound copper wires, which are coated in an insulating resin. Due to factors such as heat produced by the motor, that resin becomes increasingly brittle as time goes by. It eventually cracks and fails, at which point the motor has to be replaced.
Unfortunately, before that point is reached, there's no simple way of determining just how degraded the resin has become. That said, scientists from Germany's Martin Luther University Halle-Wittenberg – and the Elantas insulating materials company – recently discovered that four commonly used resins all gradually release a specific type of alcohol in response to heat.
The researchers experimented with various dyes that bind with that alcohol, and that don't compromise the functional properties of the resin. They ultimately selected one that ordinarily glows reddish-orange when exposed to ultraviolet light, but that turns green when bound with the alcohol. The greater the amount of alcohol that's present, the greener the dye fluoresces.
It is now envisioned that electric motors could be equipped not only with resin containing the dye, but also with compact optical reader devices that would periodically check the state of that resin. If it was determined that the resin was becoming seriously degraded, the vehicle owner would be alerted.
Such a system could spare drivers from roadside breakdowns, plus it might also ensure that still-functional motors weren't prematurely replaced based on nothing more than an estimate of their lifespan.
A paper on the research, which is being led by the university's Prof. Wolfgang Binder, was recently published in the journal Advanced Materials.
