Real engineers optimize for whatever the bean counters tell them to optimize for. In his case, lower production cost and lower weight. But the lessons he learned 30 years ago were before robots took over large parts of the car assembly process. How many of the lessons learned are still relevant or correct?
Elon Musk tried to use too many robots in the initial Model 3 assembly line:
https://www.shrm.org/resourcesandto...robots-replace-humans-just-ask-elon-musk.aspx
Robots can do everything people can do, Musk reasoned, but many, many times faster—so why not take the people, who are a drag on production speed, out of the equation? His stated goal: to achieve a 20-fold increase in production speed for Tesla's Model 3 electric vehicle and be cranking out 20,000 cars per month by the end of 2017.
But a funny thing happened on the way to future: the robots weren't quite up to the task. While Musk had promised production of 20,000 Model 3s per month by December, a mere 2,425 rolled off the line for all of the last three months of 2017, leading up to a record loss in Q1 2018 of $785 million. Ultimately, Musk had to reverse course, pulling his new robots off the lines and hiring hundreds of employees a week to rescue the Model 3 targets.
As Tesla continues to burn through its cash, the missed production targets have resulted in order cancelations, a falling share price and downgrades on both stock and debt. In July, Tesla claimed it had hit the 5,000-per-week production target, but a nervous Street seems not at all confident that the rate is sustainable.
Musk offered his mea culpa in a tweet: "Excessive automation at Tesla was a mistake. To be precise, my mistake. Humans are underrated."
Robots have a role as a human augment, not a replacement.
There are always trade-offs. Cost, weight, longevity, repairability, reusability, and finally recyclability. The term "planned obsolescence" comes to mind - the bean counters want cheaper and cheaper parts, and engineers like Munro help to provide them, resulting in things that break sooner (the joke is they break the day after the warranty runs out). I might also argue that engineers like Munro helped to give Detroit the black eye that it deserved, and are the reasons that a lot of people stopped buying from Detroit, and went to other manufacturers like Toyota.
Reliability is a function of the number of parts and processes needed to assemble them. Munro points out fewer is better than more.
His dislike of threaded fasteners means that reparability goes out the window - he just throws out statements like "nobody will ever try and service that". So that means that if it breaks, the whole assembly is more likely to go into the landfill, and repair costs for the customer go up. For a small and inexpensive assembly, maybe that's not an issue.
One of the biggest EV advantages is the more than two orders of magnitude fewer moving parts. So we don't have oil changes, air filter changes, PVC changes, transmission fluid changes, ... If you don't have a part, it can't break or wear out.
It may well be that when battery packs come out of service, that they can have a 2nd life in powerwall applications. But one might need to open the thing up and make repairs (possibly either swap out or bypass a bad cell). If the whole thing is sealed up and riveted shut, that is more difficult.
A former Prius owner, I still have some first generation, NiMH modules around. There were systemic design problems. So a small cottage industry sprang up that rebuilt traction battery packs using salvaged modules. But there were a lot of badly done rebuilds and since then, Toyota went with LiON packs.
Similar for recyclability - for something to be truly recyclable, the value of the materials recovered need to be high enough to make it worth the trouble. Metals are oftentimes the 1st thing that come to mind - copper from the motor might be highly desirable, but if you make it too hard to get to, it might not be done at large scale. Metals in the battery packs (Lithium, Nickel, Cobalt, etc)
What you do is build a tunnel. At one end a piston pushes the bad packs in. At the other end, miners recover the materials at a fraction of the cost of raw material mining and refining.
Injection molded plastic can't be recycled at all - that goes straight to the landfill. He did a whole video of an ID.4 battery teardown and they talked about an replacing the battery box with an injection molded plastic frame, that would be bonded shut. I suspect that to open such a thing, you would need to saw it open, which basically means the whole thing can't be repaired. The most expensive part in the whole car, and he proposes making it a throwaway. I just shake my head.
You'll really hate the Tesla structural 4680 pack that becomes a primary, load bearing part and battery:
More technical details:
Bob Wilson
