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1/ There are many aspects to the Tripp story.
There is the aspect of scrap and waste and whether that's being reported correctly.
There is the aspect of lying about an employee, assassinating one's character and spying on employees.
There is the aspect of lying to the press
There is the aspect of scrap and waste and whether that's being reported correctly.
There is the aspect of lying about an employee, assassinating one's character and spying on employees.
There is the aspect of lying to the press
2/ And then there is the aspect of whether Tesla was engaging in reckless disregard for human life by allowing dangerous punctured/dented cells into cars.
Here I'm only going to focus on punctured/dented cells aspect of the case and consolidate my findings in a summary.
Here I'm only going to focus on punctured/dented cells aspect of the case and consolidate my findings in a summary.
3/ In Tripp's words, "[a]round the end of Jan [2018] during maintenance, a teach pin was left on a robot, which picks up module assemblies. It began puncturing the housing (clamshell), piercing/puncturing into the cells over time, as the teach pin began unthreading."
4/ As far as I can tell, a battery pack is made of modules. Modules are made of bandoliers. And bandoliers are made up of cells. So this robot, pictured below, starts damaging the cells but the problem is discovered and dealt with too late.
5/ I refer to full email sent by Vladislav Khylzov below on February of 12th 2018. It summarizes the problem.
Because the problem is discovered so late (great manufacturing process), the number of damaged cells/modules is too high. https://twitter.com/NegDiscountRt/status/1294036626696548352?s=20
Because the problem is discovered so late (great manufacturing process), the number of damaged cells/modules is too high. https://twitter.com/NegDiscountRt/status/1294036626696548352?s=20
6/ By the way, because the problem was discovered so late, some damaged cells with *no rework* have already made it to Fremont from Reno. People in Fremont are scrambling to contain the issue. Some already make it to cars. See below. https://twitter.com/NegDiscountRt/status/1293866095279996928?s=20
7/ No back to Reno in early February. Because the damage is so extensive, instead of scrapping everything that touched the robot, they agree on the following rework procedure. From the Khylzov email referenced in 5:
8/ I don't claim to understand all of it. What I can tell (and Tripp confirms my understanding) is that if a cell is damaged too much, the module is scrapped. If it's damaged moderately, they disconnect the cell from other cells by plucking the connecting wire bonds.
9/ This way, the damaged cell is *still* in the module but it's electrically and thermally isolated from other cells.
Now you might argue that leaving a battery cell with a dent inside the module (no matter how isolated) is still dangerous - it could still combust.
Now you might argue that leaving a battery cell with a dent inside the module (no matter how isolated) is still dangerous - it could still combust.
10/ Note also that disconnecting a dented cell will lower the storage capacity of the battery. Essentially these cars with the reworked battery have fewer cells than a normal M3 has.
Here's how a Tesla person describes the rework: https://twitter.com/NegDiscountRt/status/1294029974614298624?s=20
Here's how a Tesla person describes the rework: https://twitter.com/NegDiscountRt/status/1294029974614298624?s=20
11/ Let me also briefly note these SQL queries that Tripp does to check that yes there are car batteries with dented cells that have been isolated in a rework. https://twitter.com/NegDiscountRt/status/1293923485178363907?s=20
12/ Now forward to October 2018. Tripp is fired and falsely accused of attempting mass murder. Tesla engineers still deal with the fallout from the damaged cell crisis (referred internally as AR-622 containment). But most interestingly, $TSLA issues a TSB: https://twitter.com/NegDiscountRt/status/1293883261329047552?s=20
13/ If you read the TSB, it correctly describes that some cells have their wirebond plucked off, that this reduces the capacity of the battery and the vehicle range.
What it doesn't tell is that this was done ON PURPOSE by Tesla as a rework for a manufacturing defect.
What it doesn't tell is that this was done ON PURPOSE by Tesla as a rework for a manufacturing defect.
14/ And we come to the conclusion.
Was the rework *safe enough* to sell the cars with dented cells to the public?
Was the TSB a stealth recall due to safety concerns *as well as* battery range concerns?
I do not know. I hope @NHTSAgov can answer my questions.
Thank you.
Was the rework *safe enough* to sell the cars with dented cells to the public?
Was the TSB a stealth recall due to safety concerns *as well as* battery range concerns?
I do not know. I hope @NHTSAgov can answer my questions.
Thank you.
