GM Announces Enhancements to Chevrolet Volt

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scottf200

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GM Announces Enhancements to Chevrolet Volt
Changes follow NHTSA investigation into post-severe crash battery performance
2012-01-05

WARREN, Mich. – General Motors today announced enhancements to the vehicle structure and battery coolant system in the Chevrolet Volt that would further protect the battery from the possibility of an electrical fire occurring days or weeks after a severe crash.
<snip>

For the images, statements, animations, etc. (tip watch animation full screen).
http://media.gm.com/content/media/us/en/gm/news.detail.html/content/Pages/news/us/en/2012/Jan/0105_volt" onclick="window.open(this.href);return false;
Thanks to PF for posting this.
1325780256615.jpg

Larger image in link above.

Here is the animation:
wave.gif

http://brightcove.vo.llnwd.net/pd19/media/1050888044001/1050888044001_1366548732001_Volt-Production-Solution.mp4" onclick="window.open(this.href);return false;

Step 1. Shows that there already existed a brace and they are beefing it up (only 2-3 lbs total for all braces)
2012-chevrolet-volt_100375661_m.jpg

BIG picture link of above: http://media.gm.com/content/Pages/n...ile.res/ChevroletVoltPartsInstallation115.jpg


Step 2. Notice brace from above is attached now.
2012-chevrolet-volt_100375660_m.jpg

BIG picture link of above: http://media.gm.com/content/Pages/n...ile.res/ChevroletVoltPartsInstallation084.jpg
 
The pictures would seem to suggest that the battery pack will need to be removed to incorporate the additional bracing components... That, along with the additional coolant sensor (which which would, presumably, also require wiring and a software update to integrate in to the car), would seem to indicate that this is not going to be a trivial upgrade that is done while the customer waits...
 
The extra bracing looks pretty cheap and simple, but it must be fairly expensive as a retrofit, and add a little more cost and weight to future Volts.

Will one of you Voltiacs explain this "hazard" mitigation?

General Motors is adding a tamper-resistant bracket to the top of the battery coolant reservoir to prevent potential coolant overfill
Click to expand...
 
From the Barra Volt doc in link above (see right hand side of web page):

If you’ll remember, NHTSA began testing the Volt battery after one of the vehicles it crash tested in May caught fire three weeks after the test. We cooperated fully with NHTSA during the testing and analysis period. Based on this work, GM determined the fire was the result of a minor intrusion from a portion of the vehicle into a side section of the battery pack. This intrusion resulted in a small coolant leak inside the battery, approximately 50 ml or one-quarter cup of fluid.
<snip>
Beginning in February, dealers will begin making these modifications for current Volt owners. When production resumes at the Volt plant this month, we’ll integrate similar structural enhancements into the body shop manufacturing process.

In addition to these structural modifications, we’re going to make enhancements to the battery cooling system First, we’re going to be:
- Installing a sensor in the reservoir of the battery cooling system to monitor coolant levels.
- We’re also adding a tamper-resistant bracket to the top of the battery coolant reservoir to help prevent potential coolant overfill.

The Volt’s battery cooling system is sealed and protected, but again we’re taking these steps to provide peace of mind for our customers.

These enhancements should prevent battery pack intrusion and coolant leakage thereby eliminating the risk of a post-crash electrical fire like the one in the NHTSA side impact pole test. These will also be helpful to the automotive industry as the adoption of electrification technologies expand.

I want to be clear that today’s actions have nothing to do with the battery pack itself. None of these changes will touch the battery cell or pack. As a result we will not change any part of the manufacturing process at our Brownstown, Michigan, battery pack assembly plant. We have tested the Volt’s battery system for more than 285,000 hours, or 25 years, of operation.

It’s important to note, the battery cell design used in the Volt was not the cause of the incidents that prompted the investigation. We’re confident in the robustness, quality and safety of the cell chemistry used in the Volt battery, which is supplied by LG Chem.

Before we chose LG as our cell supplier, we put their battery through extensive abuse testing, including mutilation, puncture and overcharge scenarios. We took the cell pouch and literally twisted it, crushed it and even punched nails through it. We’re as confident as ever that the cell design is among the safest on the market.

We’ve also seen a lot of speculation regarding the Volt battery’s liquid cooling system. Early in development we decided to use liquid cooling because of the benefit it provides for performance and overall battery life. It’s why we were able to provide our customers with what was the longest Electric Vehicle battery warranty when it was announced – eight-years or 100,000 miles. Key competitors have now followed our lead and are offering similar battery warranties. We still believe liquid cooling is the best option for the Volt.
Click to expand...
 
Nice report and pictures at bottom of this article as well.

http://www.greencarreports.com/news/1071348_chevrolet-to-offer-volt-modifications-against-battery-fire-risk" onclick="window.open(this.href);return false;
The modifications include additional side safety structural pieces, totaling only 2 or 3 pounds, to spread the load of a severe side impact away from the battery pack, eliminating the possibility of intrusion into the pack.
Click to expand...
Pictures link: http://www.greencarreports.com/pictures/1071348_chevrolet-to-offer-volt-modifications-against-battery-fire-risk_gallery-1#100375658" onclick="window.open(this.href);return false;
 
scottf200 said:
1325780256615.jpg

Larger image in link above.
Click to expand...
I'm surprised the intrusion happenned to the battery in the tunnel, that is far from the side of the car. Did the pole go all the way and hit the battery ?
 
I suspect that the brace that you see running laterally from the edge of the car to the battery tunnel acted essentially like a battering ram when hit by the pole and penetrated the battery case...
evnow said:
I'm surprised the intrusion happened to the battery in the tunnel, that is far from the side of the car. Did the pole go all the way and hit the battery ?
Click to expand...
 
evnow said:
scottf200 said:
1325780256615.jpg

Larger image in link above.
Click to expand...
I'm surprised the intrusion happenned to the battery in the tunnel, that is far from the side of the car. Did the pole go all the way and hit the battery ?
Click to expand...
In my fist post is a link to a web pages that has animation, documents and pictures. See right hand side of web page.
Here is the animation:
http://brightcove.vo.llnwd.net/pd19/media/1050888044001/1050888044001_1366548732001_Volt-Production-Solution.mp4" onclick="window.open(this.href);return false;
First, we’re going to strengthen an existing portion of the vehicle’s safety structure that protects the battery pack in the event of a severe side collision.
I’ll show you what I mean. As you can see the current steel tunnel of the car acts as a safety cage surrounding the battery pack. The side pole test impacts the car directly in line with the cross car structure shown in the animation. The structural enhancements more evenly distribute the load to further protect the battery and the coolant lines in the event of a severe side crash.
Click to expand...
 
TomT said:
I suspect that the brace that you see running laterally from the edge of the car to the battery tunnel acted essentially like a battering ram when hit by the pole and penetrated the battery case...
Click to expand...

I think that brace goes all the way thru, there is a notch in the battery case for it.
 
scottf200 said:
Here is the animation:
http://brightcove.vo.llnwd.net/pd19/media/1050888044001/1050888044001_1366548732001_Volt-Production-Solution.mp4" onclick="window.open(this.href);return false;
Click to expand...
That video shows the changes quiet clearly. I wonder how they plan to replace the existing steel structure and replace it with the beefier and additional steel plates? Usually those types of things are tack welded in. Not easy to remove. I imagine that a retrofit would not tack weld the new bits in but perhaps use a high strength epoxy instead (think the same stuff used to bond airplane parts together).

Would love to see the TSB GM issues for this.
 
Herm said:
TomT said:
I suspect that the brace that you see running laterally from the edge of the car to the battery tunnel acted essentially like a battering ram when hit by the pole and penetrated the battery case...
Click to expand...
I think that brace goes all the way thru, there is a notch in the battery case for it.
Click to expand...
Thx. I added pictures to the first post that shows there already existed those braces that go all the way through and they are adding to them.
http://www.mynissanleaf.com/viewtopic.php?p=163896#p163896" onclick="window.open(this.href);return false;
 
scottf200 said:
Thx. I added pictures to the first post that shows there already existed those braces that go all the way through and they are adding to them.
Click to expand...
Nice - looks like it's a simple bolt-in affair for all additional bracing?
 
http://www.nhtsa.gov/About+NHTSA/Press+Releases/2012/Statement+of+National+Highway+Traffic+Safety+Administration+On+General+Motors'+Plan+to+Address+Potential+Fire+Risk+in+Chevy+Volts" onclick="window.open(this.href);return false;

Statement of National Highway Traffic Safety Administration On General Motors' Plan to Address Potential Fire Risk in Chevy Volts

FOR IMMEDIATE RELEASE
January 5, 2012

WASHINGTON, DC — The National Highway Traffic Safety Administration (NHTSA) issued the following statement today on the plan announced by General Motors for addressing the potential risk of fire in Chevy Volts that have been involved in a serious crash:

As the primary safety agency tasked with reducing fatalities and injuries on our nation’s roadways, the National Highway Traffic Safety Administration is deeply committed to saving lives and protecting motorists. That’s why over the past four decades, NHTSA has built a robust, data-driven program to identify, assess, and help address potential safety defects in the more than 254 million registered vehicles in the United States.

In keeping with the agency’s core safety mission, NHTSA opened a safety defect investigation into the potential risk of fire in Chevy Volts that have been involved in a serious crash on November 25. The agency has not concluded that investigation and is continuing to gather and assess information on the post-crash fire risk in these vehicles.

Based on the work that NHTSA has already completed — under the observation of representatives of General Motors and in close consultation and collaboration with experts from the Department of Energy, and the Department of Defense — it appears that both battery intrusion and coolant leakage must be present to enable post-crash fire in the Volt. While the agency remains unaware of any fires from real-world crashes involving the Volt, each of the known cases of fire resulting from laboratory crash tests included these conditions.

NHTSA crashed a Chevy Volt retrofitted with GM’s newly designed steel reinforcement device in a side-pole impact test on December 22. The results of that crash test showed no intrusion into the vehicle’s battery compartment, and no coolant leakage was apparent. As a precaution, NHTSA has monitored the crashed vehicle since the test and will continue to do so for one more week. However, the preliminary results of the crash test indicate the remedy proposed by General Motors today should address the issue of battery intrusion.

In the coming weeks, NHTSA will complete the analysis of the overall research undertaken since the initial fire incident in June. The agency will make public its conclusions and any corresponding implications for consumers, the emergency response community, and tow truck operators and storage facility managers upon closure of the safety defect investigation.
Click to expand...
 
It is ironic that Tesla and GM criticized Nissan for not having active thermal management for the battery but it is the coolant running through the battery that puts it at greatest risk. Fisker had a recall for leakage problems. Maybe Nissan was wisest of all to design their battery the way they did!
 
SteveInSeattle said:
It is ironic that Tesla and GM criticized Nissan for not having active thermal management for the battery but it is the coolant running through the battery that puts it at greatest risk. Fisker had a recall for leakage problems. Maybe Nissan was wisest of all to design their battery the way they did!
Click to expand...
I don't think GM publicly criticized the Leaf for a lack of a TMS. I think that was Musk and Ford. But the reality is that the absence of a TMS on the Leaf is a problem and that criticism would be in order. A TMS will extend the life of the battery, significantly in some climates. I've never understood why anyone would buy rather than lease a Leaf that didn't have one.

With respect to "the fix", GM keeps saying the Volt is completely safe with respect to battery fires. Proof of this assetion would be that the Volt has been driven over 20 million miles without a problem. So how exactly does reinforcing the battery casing help? The "fix" just seems like a meaningless PR exercise to give people the illusion that the car is safer when it's not, passing one test that was never a problem in the first place and allowing everyone to declare victory and move on. AFAIK no one has laid out a single real world situation where any of the modifications would be helpful.

The good news is that the cells are unrelated to even this non-existential threat of fires, which should be comforting since the Leaf's chemistry is similar to the Volt's.
 
I fear GM's battery fix leaves the Volt with almost the same risk of fire as before, and that is of course the risk of carrying a gas tank. :) Oh wait, that's the same risk as every ICE car. No wait, it's less risk than most ICE cars because the Volt gas tank is only 9 gallons. Not that it would stop propaganda hacks like the National Legal Policy Center from writing dozens more anti-EV articles the first time a Volt gas tank explodes. Still it's a good PR action on GM's part to reduce the already infintesimal risk of a battery fire.
 
SanDust said:
SteveInSeattle said:
It is ironic that Tesla and GM criticized Nissan for not having active thermal management for the battery but it is the coolant running through the battery that puts it at greatest risk. Fisker had a recall for leakage problems. Maybe Nissan was wisest of all to design their battery the way they did!
Click to expand...
I don't think GM publicly criticized the Leaf for a lack of a TMS. I think that was Musk and Ford. But the reality is that the absence of a TMS on the Leaf is a problem and that criticism would be in order. A TMS will extend the life of the battery, significantly in some climates...
Click to expand...

How significant, is conjecture, not fact.

Nissan also could have extended battery (undoubtedly much more significantly, for the vast majority of LEAF owners/leasers) by life by limiting available battery capacity, as did GM.

IMO, the unsung heroes of the GM Volt rollout, were the lobbyists who secured a $7,500 federal tax credit, for a plug in hybrid with (IIRC) only 10.5 kWh available battery capacity.
 

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