What does InsideEVs think about Munro's recent analysis of Tesla Model 3 body design?

Autoline After Hours just presented a lengthy discussion with Sandy Munro and Bloomberg’s David Welch on the Tesla Model 3 design. Autoline’s discussion was mostly positive about the Model 3. However, Sandy Munro definitely has a negative opinion of the Model 3 body design. He says it’s over-designed and, as a result, heavier and more expensive.

The crux of his criticism centered around some interesting observations of the Tesla “Body in white”.

For background, check out 8:47 in the video

-The torsional rigidity of the Model 3 body is the same with or without the battery pack in the vehicle.

-The Model 3 body weighs as much as BMW’s 328i body which is one of the heaviest in its class ... and that’s with the glass roof AND the battery pack removed.


Not using the battery case as the primary crash protection and provide increased torsional rigidity was intentional on Tesla’s part.

We already know that Tesla has moved the crash protection duties from the battery pack to the vehicle structure in Model 3. We covered that in a separate article back in May. In the Model S and Model X there is a beefy ¼ inch thick case around the battery pack that protects the battery cells in an accident and adds rigidity.  But the Model S and X battery case is HEAVY. According to Jason Hughes it’s close to 300 pounds.

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Tesla did not want to ship all that additional weight from its Nevada Gigafactory to final assembly plant in Fremont, California. More weight and more volume just adds to transportation costs.

In Model 3, the side crash protection is provided by the steel body, not the pack.

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*Photo credit Jack Rickard EVTV

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*Photo credit Jack Rickard EVTV

If you're going to have a steel body, you might as well take advantage of it. Why add a lot of redundant side crash protection to the battery case if the body frame? Just by nature of its construction and material (high strength steel), does it already do the job?

So, it's no wonder that Tesla’s body in white is as heavy as the 328i. Tesla’s body must provide side protection for the battery pack. Tesla purposely took weight out of the pack case and transferred it to the body to minimize the battery pack weight and to cut transportation costs.

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