In response to two widely reported Model S incidents this past year-where road debris were run over, hit the underside of the cars and ended in battery fires-Tesla has developed a bolt-on deflector assembly available free to current owners. This change has been included in new cars, and our Model S has been given this simple, efficient upgrade. (Read our complete Tesla Model S road test.)
Tesla describes the fix as “titanium underbody aluminum and shield deflector plates.” It’s not much to think about.
With the car up on a lift, all you see is a flat silvery bar about four inches wide and two feet across covering the front edge of the ballistic-grade armored battery case, which occupies most of the car’s underbody. That visible metal strip may be the “aluminum extrusion.” Pulling off the plastic cover forward of the battery pack reveals the “titanium plate” that is painted black. The third piece is the most forward component a “hollow aluminum deflector bar,” also under the plastic shrouding.
This modification must provide significant protection to the battery pack. Fire-related incidents last year involved vehicles striking a considerable piece of road debris at highway speed. In one case, a trailer hitch evidently pierced the battery case. No one was injured in these incidents. The National Highway Traffic Safety Administration conducted an investigation and determined that Tesla’s proposed modification would mitigate the fire risk (see PDF). All Model S cars rolling off of the Fremont, Calif., assembly line are fitted with it and the company is actively conducting a customer support campaign, since March 6.
Front of car are at top of image.
In some circles online, there were assumptions how the shield would cover the whole battery-that might have been costly and would add weight. According to NHTSA’s summary of events, it was debris strikes against the battery’s front edge that precipitated the sole two fires known to date, and.
If Tesla’s debris-deflector works as anticipated, it’s an elegantly simple solution. The new components are unlikely to change the aerodynamics of the car or add any significant weight.
Having our upgrade made was really a simple process, aided with the Tesla service center in Milford, Conn., picking up the auto and returning it in two days, at no cost. We applaud the way Tesla has addressed this risk and appreciate the customer service. Other automakers would prosper to emulate how this young company deals with potential problems.