New photos from Tesla Model 3’s Body Repair Tech Note reveal a metal composition for the vehicle’s structure that strikes a perfect balance between world class safety and cost effectiveness.
One might recall Tesla CEO Elon Musk giving a tonque-in-cheek response about Model 3’s 5-star safety rating during a speech in Fremont, California. “The Volvo [S60] is arguably the second safest car in the world”, said Musk while alluding to the fact that Model 3 takes top honors for being the safest car in the world.
Photos posted to Twitter and shared on Reddit illustrate just how Tesla has been able to achieve a Model 3 body structure design that’s lightweight and has unparalleled strength at an entry level price point.
Looking at a front quarter exploded view of the Model 3 body, one can see the various compositions of steel the Tesla engineers used across the machine-stamped, multi-layer structure.
Tesla uses three different grades of steel, from mild steel used on the outer body structure where it’s designed to absorb initial impacts, and high-strength, to ultra high-strength used in the vehicle’s core. For instance, the A-pillar and B-pillar (noted in red on the graphic) is fabricated from ultra high-strength steel in order to provide maximum rollover protection. Model 3’s front frame rail is a composition between high-strength and ultra high-strength steel, and serves as the main support for the front “crumple zone”.
Tesla Model 3’s body repair manual notes that “Structural Pulling” is not allowed, meaning that any structural component that’s welded, weld-bonded, riveted, or rivet-bonded to the vehicle can not undergo a process wherein the straightening of structural parts are facilitated through a hydraulic pulling machine. Doing so would compromise the yield strength of the metals being used.
Also noted in the Model 3 structural diagram is the “underbelly” that serves as the main support for Model 3’s skateboard style battery pack, similar to what’s used in its older Model S and Model X siblings. The entire underside of the vehicle is fabricated from high-strength steel.
Side impact safety on the Model 3 is bolstered by a fully fortified closed steel structure in ultra high-strength steel. Looking at the crash test video showing a side-pole impact test performed on Tesla’s Model 3 and Volvo’s S60, one can easily see the level of deformity the Volvo has over the Model 3.
Lastly, lightweight aluminum is introduced in areas of the body structure that are less susceptible to accidental impact such as the trunk floor and wheel wells. Using aluminum helps Model 3 maintain a relatively light curb weight of 3,549 lbs. for the standard version and 3,814 lbs. for the Long Range Model 3 with larger (and heavier) battery pack.
All in all, Tesla’s use of various steels and aluminum in Model 3’s body structure can be seen as a learning experience and first iteration towards even more affordable and higher volume production down the road – Model Y.