Even tho I work in the tech industry, I don't do much with Facebook, so not sure how to link to the post. ;-)
It was in this forum: (Thanx for the non-mangled link!)
(Note: The below was not posted by me.... Just passing this along..)
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Hi friendly neighborhood volt/bolt tech here! First let me say that I am not an official GM spokesperson and I am expressing my interpretations of the information I have gathered. It is absolutely possible not every detail is exactly correct and things certainly could change as the process progresses and more is learned.
We received both of the final recall procedures and updated info at the dealer today and I thought I would update you all on what I have been able to gather as a master gm technician of 15 years, gold certified high voltage hybrid/ev specialist, and ev enthusiast. We'll start with the potential causes of the fires as I have come to understand it.
GM originally identified a manufacturing defect present in some battery cells (I'm not sure which of the 2 was identified first), and proceeded to develop and deploy a software "final fix" that they believed would identify a defective cell before it propagated into a fire by monitoring for excessive cell voltage variation among other things. If this was the only defect present this software likely would have been successful in averting any further fires. After this software proved unsuccessful the investigation intensified and after inspecting many batteries and LG's manufacturing processes, a second defect was uncovered. The two possible defects identified are a torn anode tab and a folded seperator. Neither one of these defects are a real big deal independently but in the very rare case that they both occur within the same cell, the combination of the two can create a point of failure. That point of failure still needs to be aggrivated though, and this is where different operating conditions and vehicle uses come in.
Current draw, charging rates, ambient temperatures, battery temperatures, fully charging/deep discharging often, etc all produce different heating and cooling patterns for each individual bolt. Only some sets of specific use conditions will cause the cell's expansion and contraction rates to be large enough to allow a short in the cells that contain both defects.
Now for the final... final fix.
Gm believes they have identified certain build date time frames that the defects seem to be clustered, so those vehicles will have initial priority. Customer owned vehicles currently awaiting repair after failing either the on-board or dealer battery module diagnostics will also be prioritized. I suspect vehicles with the specific identified use patterns that are most likely to produce the largest cell expansion and contraction rates will likely also be prioritized as well, but haven't specifically confirmed that. Every bolt is currently under one of two recalls, N212345940 (2020-2022) or N212343880 (2017-2019). Once vehicles are eligible for repair they will be migrated from N212343880 to N212343881 and from N212345940 to N212345941. These two new recall numbers are what we got copies of today at the dealer. They both clearly state the correction as "Dealers will replace the lithium-ion battery pack in the vehicle." I have read all 50 pages of each recall and there are no inspections or section/module/row replacements, or software only repairs. There are dozens of required tools and pieces of equipment for this recall (including a forklift to load and unload multiple batteries), and the tools that would be needed specifically to replace modules/sections are not required for this recall. As of this writing all vehicles will be getting a whole, brand new, complete, fully assembled battery pack. Remember though this is a constantly evolving situation and more is being learned every day. If they discover a reliable way to identify the defective cells after inspecting tens of thousands of returned batteries, it's not impossible they would modify the recall to replace only defective modules. I don't personally think that is very likely but I've learned over the years nothing is impossible. We have already ordered our first three packs and have been told to expect them within 2 weeks. The new batteries will all include an extended 8-year/100,000-mile limited battery warranty.
GM has also said that within 60 days all vehicles will also get a new advanced diagnostic software package that will increase the available battery charging parameters over existing guidence while also performing new onboard diagnostics to identify and prioritize replacement for vehicles with bad cells.
Quote from GM:
"The diagnostic software will be designed to detect specific abnormalities that might indicate a damaged battery in Bolt EVs and EUVs by: monitoring the battery performance; alerting customers of any anomalies; and prioritizing damaged battery modules for replacement. It is GM’s intent that further diagnostic software will allow customers to return to a 100 percent state of charge once all diagnostic processes are complete."
GM will send letters to customers when their vehicle is migrated from the old recall to the new one and is eligible for battery replacement. The recall will take the better part of a day to complete and the vehicle must have a minimum of 24 hours between the last high voltage battery charge (plug in charging) and the beginning of the high voltage battery removal so don't plug it in the night before you take it or it'll have to sit overnight before it's worked on.
So there it is folks. That's all I currently know and hopefully it will put a few minds at ease. I'll try to answer any and all questions that I can as quickly as possible but I also work and have a 2 year old so you'll have to bear with me if it's delayed.
It was in this forum: (Thanx for the non-mangled link!)
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(Note: The below was not posted by me.... Just passing this along..)
----------
Hi friendly neighborhood volt/bolt tech here! First let me say that I am not an official GM spokesperson and I am expressing my interpretations of the information I have gathered. It is absolutely possible not every detail is exactly correct and things certainly could change as the process progresses and more is learned.
We received both of the final recall procedures and updated info at the dealer today and I thought I would update you all on what I have been able to gather as a master gm technician of 15 years, gold certified high voltage hybrid/ev specialist, and ev enthusiast. We'll start with the potential causes of the fires as I have come to understand it.
GM originally identified a manufacturing defect present in some battery cells (I'm not sure which of the 2 was identified first), and proceeded to develop and deploy a software "final fix" that they believed would identify a defective cell before it propagated into a fire by monitoring for excessive cell voltage variation among other things. If this was the only defect present this software likely would have been successful in averting any further fires. After this software proved unsuccessful the investigation intensified and after inspecting many batteries and LG's manufacturing processes, a second defect was uncovered. The two possible defects identified are a torn anode tab and a folded seperator. Neither one of these defects are a real big deal independently but in the very rare case that they both occur within the same cell, the combination of the two can create a point of failure. That point of failure still needs to be aggrivated though, and this is where different operating conditions and vehicle uses come in.
Current draw, charging rates, ambient temperatures, battery temperatures, fully charging/deep discharging often, etc all produce different heating and cooling patterns for each individual bolt. Only some sets of specific use conditions will cause the cell's expansion and contraction rates to be large enough to allow a short in the cells that contain both defects.
Now for the final... final fix.
Gm believes they have identified certain build date time frames that the defects seem to be clustered, so those vehicles will have initial priority. Customer owned vehicles currently awaiting repair after failing either the on-board or dealer battery module diagnostics will also be prioritized. I suspect vehicles with the specific identified use patterns that are most likely to produce the largest cell expansion and contraction rates will likely also be prioritized as well, but haven't specifically confirmed that. Every bolt is currently under one of two recalls, N212345940 (2020-2022) or N212343880 (2017-2019). Once vehicles are eligible for repair they will be migrated from N212343880 to N212343881 and from N212345940 to N212345941. These two new recall numbers are what we got copies of today at the dealer. They both clearly state the correction as "Dealers will replace the lithium-ion battery pack in the vehicle." I have read all 50 pages of each recall and there are no inspections or section/module/row replacements, or software only repairs. There are dozens of required tools and pieces of equipment for this recall (including a forklift to load and unload multiple batteries), and the tools that would be needed specifically to replace modules/sections are not required for this recall. As of this writing all vehicles will be getting a whole, brand new, complete, fully assembled battery pack. Remember though this is a constantly evolving situation and more is being learned every day. If they discover a reliable way to identify the defective cells after inspecting tens of thousands of returned batteries, it's not impossible they would modify the recall to replace only defective modules. I don't personally think that is very likely but I've learned over the years nothing is impossible. We have already ordered our first three packs and have been told to expect them within 2 weeks. The new batteries will all include an extended 8-year/100,000-mile limited battery warranty.
GM has also said that within 60 days all vehicles will also get a new advanced diagnostic software package that will increase the available battery charging parameters over existing guidence while also performing new onboard diagnostics to identify and prioritize replacement for vehicles with bad cells.
Quote from GM:
"The diagnostic software will be designed to detect specific abnormalities that might indicate a damaged battery in Bolt EVs and EUVs by: monitoring the battery performance; alerting customers of any anomalies; and prioritizing damaged battery modules for replacement. It is GM’s intent that further diagnostic software will allow customers to return to a 100 percent state of charge once all diagnostic processes are complete."
GM will send letters to customers when their vehicle is migrated from the old recall to the new one and is eligible for battery replacement. The recall will take the better part of a day to complete and the vehicle must have a minimum of 24 hours between the last high voltage battery charge (plug in charging) and the beginning of the high voltage battery removal so don't plug it in the night before you take it or it'll have to sit overnight before it's worked on.
So there it is folks. That's all I currently know and hopefully it will put a few minds at ease. I'll try to answer any and all questions that I can as quickly as possible but I also work and have a 2 year old so you'll have to bear with me if it's delayed.