[RickWoodbury]

In order to install a 90 kWhr pack in a Tango T600, I need to modify 6 Tesla Modules by reducing them from 6S to 4S, thus removing the 148 cells from the coolant connection end. These 6 modules would be in series with 12 full-sized modules, giving 96S, exactly the number of cells as in a Model S P90D.

Does anyone have experience disassembling a Tesla module? Not only is the aluminum plate glued to the plastic, but I find the cells also glued to the plastic.
Is there a chemical means of separating? I don't think heat would be a good idea. I've cut the fusible links on each of the cells being removed, and plan to re-bond the 14 cells that have to be relocated in each of the 6 modules. I'd much appreciate any ideas on making this job easier.

Thanks,

Rick

 

[RickWoodbury]

Warning! I've seen posts about reconfiguring a Tesla module using a dremel to cut plates to create 12s 37p. Because only the aluminum plate was being cut and no contact with a cell is likely, he got away with it.
I, however, need to remove 148 cells from the coolant fittings end to make some of the modules shorter—4s 74p. The dremel just nicked one of the cells to be removed and it burst into flames. One cell, no big deal, however, here is the waning. The fire propagated to the next cells. Having the module on a bench, I grabbed it and put it on the concrete floor, while several cells were burning at one end. After it was on the floor, I grabbed a 5-gallon bucket of Lith-X which is a fine powder specifically designed to put out Li fires. It did nothing! As each cell or group of cells blew, they just blew the Lith-X away. It took 90 minutes for all the cells to finally burn out. Some of the cells took off like sky rockets bouncing off of our 14-foot ceiling, and some were like pinwheels as they spun through the air with flame spitting out of both ends. Most were just like Roman candles. I was nervous about the grand finale as the propagation was building until the end. Luckily it didn't get much worse. I have decided that the modules can't be modified. If anyone knows of a way to safely remove parts of the module, I'd love to hear about it, but probably won't be using Tesla modules.
I found a source for LiFePO4 18650 cells. I'll lose a lot of range, but won't have to sweat the power, as they can put out 30A and I can only use 27A with cells at 108s 75p with the 2000A Zilla controller. Stay safe. I feel very lucky.

 

[major]

Warning! I've seen posts about reconfiguring a Tesla module using a dremel to cut plates to create 12s 37p. Because only the aluminum plate was being cut and no contact with a cell is likely, he got away with it.
I, however, need to remove 148 cells from the coolant fittings end to make some of the modules shorter—4s 74p. The dremel just nicked one of the cells to be removed and it burst into flames. One cell, no big deal, however, here is the waning. The fire propagated to the next cells. Having the module on a bench, I grabbed it and put it on the concrete floor, while several cells were burning at one end. After it was on the floor, I grabbed a 5-gallon bucket of Lith-X which is a fine powder specifically designed to put out Li fires. It did nothing! As each cell or group of cells blew, they just blew the Lith-X away. It took 90 minutes for all the cells to finally burn out. Some of the cells took off like sky rockets bouncing off of our 14-foot ceiling, and some were like pinwheels as they spun through the air with flame spitting out of both ends. Most were just like Roman candles. I was nervous about the grand finale as the propagation was building until the end. Luckily it didn't get much worse. I have decided that the modules can't be modified. If anyone knows of a way to safely remove parts of the module, I'd love to hear about it, but probably won't be using Tesla modules.
I found a source for LiFePO4 18650 cells. I'll lose a lot of range, but won't have to sweat the power, as they can put out 30A and I can only use 27A with cells at 108s 75p with the 2000A Zilla controller. Stay safe. I feel very lucky.

Dude........

That's incredible. Glad you survived. Were you in a shop, barn or what? Lucky it didn't take down the structure. And you stayed and tolerated the fumes?

Thanks for the report. Any photos? Mind if I share your report with endless-sphere forum?

major

 

[Karter2]

I was under the impression that the Tesla modules were fully coated in a flame/fire retardant compound after assembly specifically to prevent this type of thermal runaway ??
Ahh well, there goes another internet myth !

 

[Duncan]

I was under the impression that the Tesla modules were fully coated in a flame/fire retardant compound after assembly specifically to prevent this type of thermal runaway ??
Ahh well, there goes another internet myth !

I dunno - something that works perfectly when it is in it's proper place may not work as well when somebody has it partially disassembled and is busy doing things the design engineer may not have thought of

 

[weber]

It seems like there is little consensus on how best to deal with lithium ion battery fires (which seems crazy at this stage of the game) but it's not surprising that Lith-X was useless since it is intended for fires where lithium metal is the fuel and air is the oxidiser, while lithium-ion cells beyond a certain temperature contain both fuel and oxidiser -- exactly like fireworks. What saves us with LiFePO4 is that they have to get to a much higher temperature than other chemistries before the oxidiser is activated. Up to that point you're just burning first the electrolyte solvent and then plastic separators and cases, in air.

It seems to me that the best bet would be to play water on it to keep it cool, to slow the cell-to-cell propagation and to prevent surrounding materials from catching fire, until it burns out.

People will say that you can't use water because it _causes_ lithium to burst into flames. But that's lithium metal (as in the non-rechargeable kind of lithium cells), not lithium ions.

Others point out that lithium metal plating can occur in lithium-ion cells under certain kinds of abuse, or old age. But is this enough to mean that we should not use water?

Then there's the fact that water will react with the LiFP6 in the electrolyte to make some toxic and lung-corroding vapours, so you don't want to do this in an enclosed space, or if you can't stay upwind of it.

Does anyone have any experience of using water on lithium-ion battery fires?

 

[dcb]

rickard had a video where he also mentioned that lithium cells are self oxidizing above a certain temperature. *maybe* you could douse it in liquid nitrogen, if that were a safe and convenient thing to do for some reason.

 

[jonescg]

Water. Lots and lots of water.
It makes a mess, but taking the heat out of the system will buy you time.

 

[RIPPERTON]

Does anyone have any experience of using water on lithium-ion battery fires?

Yes well no Lithium Polymer but a relatively small amount of water to reverse the reaction can kill a LiPo fire in 5 minutes.
Just trickling tap water over the cells can cool them enough to shut down the thermal reaction.
Yes so actual Lithium Metal fire extinguishers are useless in a battery fire.
See the amount of water trickling out of the tap.

 

[Karter2]

A member on the ES forum had a similar lipo pack start to go thermal on him whilst attempting a repair.
He was prepared and simply dumped the whole pack into a trash can of water.
It stopped the problem spreading to other cells straight away.
He videoed the whole thing....i will see if i can find it.

 

[dcb]

I wonder if discharging to 2.5v/cell offers any worthwhile increase in margin of safety.

 

[major]

And I wonder why we haven't heard from the OP since post #2. I hope the fumes didn't do him in.

 

[okashira]

What a moron.
Guy posted this doozy in my thread about selling tesla batteries:
"Anyone selling tesla batteries?"

And this 4s / disassembly garbage.

We're the best, if not single source for folks whom have removed cells and reconfigured Model S modules...

Yet I have gotten no contact from him whatsoever. Other then his troll post in my thread, that is.

Guy is a troll/idiot/freeloader and hopefully he goes away.

 

[AntronX]

Patiently waiting for pictures of the damage.

 

[major]

What a moron.
Guy posted this doozy in my thread about selling tesla batteries:
"Anyone selling tesla batteries?"

And this 4s / disassembly garbage.

We're the best, if not single source for folks whom have removed cells and reconfigured Model S modules...

Yet I have gotten no contact from him whatsoever. Other then his troll post in my thread, that is.

Guy is a troll/idiot/freeloader and hopefully he goes away.

Who are you talking about? OP only has 2 post history; both on this, his own thread.

 

[dcb]

I don't think Rick is a "shill", at least it would be really strange,

his other post mentioned the Tango (the really narrow and bottom heavy jobbie), and here is a guy named Rick Woodbury working on a Tango from the x-prize.

http://autoblog.xprize.org/axp/2010/12/gratitude-tango-commuter-cars-rick-woodbury.html

 

[okashira]

Who are you talking about? OP only has 2 post history; both on this, his own thread.

endless-sphere....

 

[DrJeff]

From the description, Rick was attempting a major modification on the module (removing 148 cells to reduce its length), but leaving the rest in place to operate as manufactured.

The warning should be... modifying a battery pack can be dangerous and hazardous, thus such a modification will require the task be designed in such a way to include 1) sufficiently accurate control of the tools, 2) waste handling (metal shavings), and 3) appropriate fire and hazard control measures in place such that the risks can be minimized.

Based on the Tango project and other postings, it is apparent that Rick is more than familiar with EVs and battery packs.

In my experience, I have found it extremely difficult to control Dremel cutting tools by hand. Given the scope of the cut and the degree of accuracy required in this case, it was inevitable that the tool would inadvertently damage one of the cells, if not multiple cells.

ICE mechanics understand the danger of working on fuel systems, fuel tanks, and tires (compressed air) with fast, hot, or hard to control tools. Likewise education on the handling and warnings on the modification of battery modules need to also become part of the common EV builder / tinkerer knowledge.

The important information isn't that packs can go on fire, rather the important information is that if you are planning to modify a battery module, they can be dangerous (electrically and chemically) and you need to fully acquaint yourself with the dangers involved and take appropriate steps to protect yourself, others, and property.

 

[RickWoodbury]

Why all the venom Okashira. I tried to contact you and got no response. I was looking for someone who I could hire to make six 4s modules so that they'd fit in the Tango battery box along with 12 more full-sized modules. This would give the Tango the same 7401 cells, 96s74p that the Tesla has. If you can make them, then please send me a quotation. I'm all over the net. I don't hide my identity in any way. I don't know why you want to call a potential customer a lot of names. It certainly doesn't increase my wish to have you do work for me, but it also doesn't close the door, at least on my side. If you can convince me that you can convert 6 Tesla modules to 4s and keep them under 20-inches long, and keep the water cooling intact, then please present a quotation. Best wishes, Rick (not a shill or a troll) Why would anyone think that? BTW, my slow response is due to being quite busy.
PS. I was wearing a very high grade gas mask the whole time. I'm fine.

 

[RickWoodbury]

I am simply trying to get the longest range battery pack that will fit in a Tango. Having received quotations from major pack developers that could do liquid cooling, at over $100k, I looked into using Tesla modules. They are very well made, and already individually fused and undergone more testing than any other system. The only problem is that I can only fit 12 full sized modules, and need 16. There is room for an additional 6 modules, if they could be 4s and under 20" long, giving the full 96s needed.
Please contact me by email if you can help or direct me. I don't think I like communicating on forums.
Rick Woodbury
Commuter Cars Corp.
www.commutercars.com
[email protected]
Office: 509-624-0762
Cell: 509-979-1815