Author Topic: Rivian 7777 battery pack not very serviceable! (2170 cell's)  (Read 1212 times)

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Offline MTTopic starter

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Rivian 7777 battery pack not very serviceable! (2170 cell's)
« on: September 27, 2022, 03:19:15 pm »
« Last Edit: September 27, 2022, 03:43:29 pm by MT »
 

Offline MTTopic starter

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Re: Rivian 7777 battery pack not very serviceable! (2170 cell's)
« Reply #1 on: September 27, 2022, 03:48:11 pm »
His recycling claims of 92% is a happy number as usually.

 

Offline thm_w

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Re: Rivian 7777 battery pack not very serviceable! (2170 cell's)
« Reply #2 on: September 27, 2022, 10:45:10 pm »
There was some note (can't find a link) about VW updating their software to alert of pack issues and bring the car in for a specific cell swap. Maybe if it gets bad it would affect nearby packs, or there could be a safety risk?

So its basically a numbers game to get lower cost to the manufacturer within 8 year warranty:
- Battery failures * full replacement cost of the battery pack
- Cell failure * cost of a cell replacement + presumably higher BMS/initial cell manufacturing costs

Of course for the end user, replaceable packs is preferred. But, you'd want to know reliability first.
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Offline james_s

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Re: Rivian 7777 battery pack not very serviceable! (2170 cell's)
« Reply #3 on: September 27, 2022, 10:51:05 pm »
I have mixed thoughts on that. In my experience with battery packs, most of the time when one cell fails the rest are already in rather poor condition. Then if you try to replace the one bad one with a new one then the others are much weaker. The best you can do usually is replace a bad cell with another used cell and squeeze a bit more life out of it. I don't think many people will be repairing EV packs themselves though, there will be businesses that buy dozens of salvage packs and rebuild them with tested and matched cells.
 

Offline MTTopic starter

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Offline thm_w

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Re: Rivian 7777 battery pack not very serviceable! (2170 cell's)
« Reply #5 on: September 28, 2022, 12:00:10 am »
I have mixed thoughts on that. In my experience with battery packs, most of the time when one cell fails the rest are already in rather poor condition. Then if you try to replace the one bad one with a new one then the others are much weaker. The best you can do usually is replace a bad cell with another used cell and squeeze a bit more life out of it. I don't think many people will be repairing EV packs themselves though, there will be businesses that buy dozens of salvage packs and rebuild them with tested and matched cells.

It seems to be a bit different in EVs, one pack can be in a poorly cooled area and get hotter, meaning it fails earlier. Or you can have a defective pack:

Quote
According to nextmove, Volkswagen distributed a memo to its dealers to tell them that some cells installed in the high-voltage battery pack of the ID.3 and ID.4 “of a limited production period (...) exhibit increased self-discharge due to a manufacturing defect.” The carmaker did not specify which manufacturing defect it is that makes the batteries lose charge.
...
Volkswagen will inspect the vehicles with an electronic service tool and replace the defective modules. The service should take a working day.
https://www.autoevolution.com/news/volkswagen-recalls-10000-id3-and-id4-units-due-to-cell-defects-199757.html

Part of this is simply due to the larger number of cells, more chance of something going wrong, add in the high energy densities and fast charging, etc.
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Online tom66

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Re: Rivian 7777 battery pack not very serviceable! (2170 cell's)
« Reply #6 on: September 28, 2022, 08:17:30 am »
Realistically, the 8 year warranty on these packs is not good enough if they're unserviceable like this.  It needs to be 15 years minimum, with a guarantee of 70% capacity at 15 years and 80% at 7-8 years.
 


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