Featured Tesla Model 3 Teardown

Source: AD #2333 – GM Slaps Big Discount on Escalade, Company Applies V2V to Racing, Tesla Has Too Many Robots – Autoline Daily

And speaking of the Tesla, you won’t want to miss this week’s Autoline After Hours. This is the show a lot of you have been waiting for because our special guest is Sandy Munro, who will be here to talk about his teardown of the Model 3. So if you have any questions, send them our way to [email protected] and join us for some of the best insider discussions in the auto industry.​

Thursday afternoon for the live program. They take calls. Sorry, I don't have the start time:
Autoline After Hours

Bob Wilson

 

Screen shots from the Sandy Munro video, this traction battery is awesome. I had my doubts about the cylindrical cells, 2170, because the battery cell cases add weight but no energy. The volume efficiency, the ratio of battery chemicals to case overhead improves with size. Large format, cells are attractive for energy density until factoring in the mechanical structure needed. In contrast, this collection of cells makes a very strong, stiff structure. It is a composite where the cells are the core.

Notice the assembly is potted with a silicon compound making it both sound deadened and stronger.

The bus bars are on the top so all of the cells are oriented the same way which simplifies automated assembly. The external 'whiskers' are spot welded to the bus bars which are layered on top:





All of the cells are in parallel, subassemblies which helps to keep them balanced. Now the real question is whether the 'whiskers' also work as a fuse. When a cell internally shorts, the excessive current might blow a 'whisker' functioning as a fuse. The silicon potting compound helps keep the by-products from impacting the other cells. BTW, Munro reports individual 2170 cells are 6000 ma. with less than 0.2 ma. difference.

Battery cooling remains an open question. The silicon potting compound would inhibit heat transfer out the sides and even the top. So it may be the bottom of the cells are in a liquid coolant or touching a heat transfer plate. Again, another good reason for having all cells oriented the same way.

Bob Wilson

ps. Blind One-armed Builder (BOB) describes plant robots.

 

Tesla responds: Tesla Model 3 Teardown: Deconstructed 3 - Motor Trend

Tesla Responds
Statement on vehicle age

“The primary car evaluated by Munro was built in 2017. We have significantly refined our production processes since then, and while there’s always room for improvement, our data already shows that Model 3 quality is rapidly getting better.”

Statement on panel gaps and offsets

“Since we began shipping Model 3 last year, we have been very focused on refining and tuning both part and body manufacturing processes. The result being that the standard deviation of all gaps and offsets across the entire car has improved, on average, by nearly 40%, with particular gap improvements visible in the area of the trunk, rear lamps and rear quarter panel. Today, Model 3 panel gaps are competitive with Audi, BMW, and Mercedes models, but in the spirit of relentless improvement, we are working to make them even tighter.”

Statement on body weight/complexity

“The U.S. government found Model S and Model X to have the lowest probability of injury of any cars it had ever tested, and Model 3 was designed with the same commitment to safety. While there’s always room for refinement of cost and mass, which we are already improving, electric cars have unique safety requirements to prevent intrusion into the battery, and Model 3 was also designed to meet the latest small overlap front crash requirements that other reference vehicles may not have. We stand behind our physical crash testing and our computer simulations of it, which have been remarkably accurate, and the safety that they demonstrate. The safety of our customers is more important than any other metric.”​

Bob Wilson