Three-point seat belts have come a long way since Volvo gave away their patents for free decades ago. Some automakers cram airbags inside, but ZF had a different idea. Check out the Heat Belt, which, true to its name, takes the form of a heated seat belt that acts as a warm hug. This is primarily intended for EVs to increase efficiency during cold weather. The thinking was that the car would use less battery to warm up the entire cabin.
While this may seem like a gimmick, the same was said about the heated steering wheel in those days. ZF has crunched the numbers and estimates the EV range in low temperatures could increase by up to 15 percent. Internal heating conductors are embedded into the seat belts to provide uniform warmth while minimally increasing the thickness of the webbing.
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Using about 70 watts of power, the seat belt can be heated up to 40 degrees Celsius (104 degrees Fahrenheit). ZF says its Heat Belts behave like regular seat belts, meaning cars don’t need to go through any modifications to accommodate them. The heating conductors are woven into the seat belt structure and the location of the contact elements for the electric heating circuit is chosen so as not to interfere with belt operation or retraction. As a result, standard belt retractors still function and the level of safety remains the same.
It should be mentioned that heated seat belts are not an absolute premiere. In late 2018, Ford filed a patent with the USPTO, publishing a 31-page document detailing how the technology works. Several variations of the concept with different designs are illustrated, but the idea is largely the same. About a year later, Mercedes introduced the GLE-based Experimental Safety Vehicle (ESF) and that one also had heated seat belts.
It’s still unclear whether the automaker intends to implement this technology, but if there is a real efficiency benefit, we expect to see heated seat belts on luxury EVs at some point.
