According to Elon Musk, CEO of Tesla
Motors, engineers have added three titanium shields to the underside of the new Model S all electric vehicle. This move comes in response to what the company describes as “two extremely unusual Model S collisions resulted in under-body damage that led to car fires”.
These 2013 incidents, received national headlines even though in both cases, the occupants walked away unharmed, thanks to the car’s safety features. In these two cases, the on-board computer warned the occupants to exit the vehicles, which they did well before any fire was noticeable. According to the company, even if the occupants had remained in the vehicle and the fire department had not arrived, they would still have been safely protected by the steel and ceramic firewall between the battery pack and the passenger compartment.
Nonetheless, we felt it was important to bring this risk down to virtually zero to give Model S owners complete peace of mind. Starting with vehicle bodies manufactured as of March 6, all cars have been outfitted with a triple underbody shield. Tesla service will also retrofit the shields, free of charge, to existing cars upon request or as part of a normally scheduled service
Shield 1 – A rounded, hollow aluminum bar that is designed to either deflect objects entirely or, in the case of a self-stabilizing, ultra high strength object, like a three ball steel tow hitch, absorb the impact and force it to pike upwards well forward of the battery pack. This pierces the plastic aeroshield and front trunk liner, but causes no damage affecting safety and the car remains in control and driveable before, during and after the impact.
Shield 2 – Shield 1 is followed by a titanium plate, which has exceptional strength-to-weight properties and is more commonly seen in aerospace or military applications. The titanium plate prevents sensitive front underbody components from being damaged and aids in neutralizing the road debris.
Shield 3 – A shallow angle, solid aluminum extrusion that further absorbs impact energy, provides another layer of deflection and finally causes the Model S to ramp up and over the object if it is essentially in-compressible and immovable.
Camera’s attached to test vehicles without the shield illustrate how the new three levels of shield react when the vehicle runs over an object. See photo
The protective qualities of the underbody shields are substantial, but their effect on the overall structure of the vehicle is minimal. In total, the shields only have a 0.1 percent impact on range and don’t affect ride or handling. Wind tunnel testing shows no discernible change in drag or lift on the car.
Source data: Tesla Blog