# Orientaton of prismatic LiFePO4 cells important?



## Nabla_Operator (Aug 5, 2011)

Can I mount the batteries in any way in the vehicle, or is method "A" the only acceptable one? 










(I want B or C in my project)

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## Ziggythewiz (May 16, 2010)

CALB says only A. I saw some TS thing once that showed A good, B okay, C bad.


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## MN Driver (Sep 29, 2009)

There are mixed opinions here but I would expect the separate layers should hold the electrolyte through capillary action. I'd venture a guess that B would be worse than C if that wasn't the case. I don't really think either is worse myself but I'd think that TS knows more about their cells and electrolyte than I do. For what it's worth GBS battery doesn't warranty their cells if they aren't standing upright, strapped to a certain PSI, and a bunch of other warranty voiding scenarios that other battery companies don't say would void the warranty. They'd only know if you told them though as I'd imagine they'd have a hard time knowing otherwise.

I know Jack Rickard used cells in the laying down in figure C formation on the Cobra pack. The problem with Jack's cars is there is no longevity to his cars or their battery packs. It seems the Mini has the oldest pack because his NEV was drained to zero volts as it wasn't disconnected before long-term inactivity and his Speedster had its battery replaced with the higher voltage project that replaced almost everything electrical in the car and the Mini has a pack that's sitting upright so it doesn't have much to do with the orientation but I think the Porsche second version may have had some figure C type formation to some of the cells. Either way, not enough time to tell in any case.

FWIW, A member of the UK BVS group ran some of the very old Thunder Sky cells laying flat(figure C) in the back of his van and his pack lasted 7 years, after the pack degraded from increased voltage sag due to calendar life issues, he sold the van. http://www.evalbum.com/413 These were pre-LiFePO4 tho so the LiFePO4 would probably have lasted longer.


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## dougingraham (Jul 26, 2011)

The last stuff I read from GBS says only D (terminals down) is bad because the excess electrolyte will eventually fill the vent. I am guessing that liquid in the vent will prevent it from working properly if it is needed. The third gen cells are essentially always always shown laying on their sides and it is clear that they are expected to be used this way. The third gen cells have the anode on one end and the cathode on the other end.

B and C seem to work fine for those who have tried it. The electrolyte wets out the insulator and they will continue to work. These arent't like flooded lead acid, there is very little excess electrolyte.


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## steven4601 (Nov 11, 2010)

Offtopic question, is that a Renault Zoe?


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## dtbaker (Jan 5, 2008)

Ziggythewiz said:


> CALB says only A. I saw some TS thing once that showed A good, B okay, C bad.


I just got a reply from Keegan and tech guy Han from CALB. Tech says A, B, C are all ok. So, first-hand response from manufacturer trumps myths. 

quote:

Hi Mr.Dan
Mounting horizontally is acceptable, because the safety valve on the battery will make sure that the electrolyte will not leak even you put them horizontally.

Best Regards
Ted
 * 中航锂电（洛阳）有限公司 上海分公司​
CALB​ 
*


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## Ziggythewiz (May 16, 2010)

dtbaker said:


> first-hand response from manufacturer trumps myths.


Do sales and tech guys trump operating manuals made by manufacturer's engineers?


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## dtbaker (Jan 5, 2008)

Ziggythewiz said:


> Do sales and tech guys trump operating manuals made by manufacturer's engineers?


sales guys are not always to be trusted, but Keegan has been pretty impressive in getting answers from the chinese engineering team when asked.... I posted the direct response from .cn engineer at CALB. 

Owners manual is entertaining reading, but I didn't see anything 'prohibiting' horizontal mount. One place says not recommended. Considering all the other weird translation issues I am pretty comfortable trusting the personal clarification from a guy on the engineering team.


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## Ziggythewiz (May 16, 2010)

Yeah, I don't know exactly know how "not recommended" translates. As with everything else lithium, there's little to no data. It could have no effect, or it could affect cycle life/failure. I guess we'll find out in 5-10 years.


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## dtbaker (Jan 5, 2008)

Ziggythewiz said:


> Yeah, I don't know exactly know how "not recommended" translates. As with everything else lithium, there's little to no data. It could have no effect, or it could affect cycle life/failure. I guess we'll find out in 5-10 years.



interesting picture there.... doesn't show choice C at all.  Also this graphic is not even IN my 'Using and Maintenance Manual' from CALB that came with batteries.

My personal opinion is that the possible downside to horizontal mount in the B orientation might just be that the inside foils would have uneven stress on the terminals if there is any movement on the interior of the case... But that position C should be 'ok' in that respect. I would also add that both the B and C orientations would make it harder to have effective thermal management either with convective cooling with open bottom or winter heating with a 'warming plate' bottom. So, yeah, A is probably best if space allows, but C is probably acceptable in most cases if thermal managament is not an issue.


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## Ziggythewiz (May 16, 2010)

dtbaker said:


> interesting picture there.... doesn't show choice C at all.  Also this graphic is not even IN my 'Using and Maintenance Manual' from CALB that came with batteries.


It's from a different manual. I think they just give it to distributors.

It would be interesting to hear CALB's take on that old explanation of why C was bad for TS. For my bug only A is useful anyway, so no issue.


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## Nabla_Operator (Aug 5, 2011)

Thank you for the replies; I now have much more freedom in filling all spaces with Lithium. 
Got some section cuts of a Thundersky 90 Ah cell for all of you:































Even in case of "C" you have a lot space for escaping electrolyt.

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## nucleus (May 18, 2012)

I don't get it - why the L shape?


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## dladd (Jun 1, 2011)

That is cool! They really pack them in there.


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## onegreenev (May 18, 2012)

nucleus said:


> I don't get it - why the L shape?


To better show off the leaves within the batter but keeps it all contained so it does not degrade. 

I have had them in all directions and I have taken them apart and there is really not much excess electrolyte and that which is excess is really not used anyway. It just helps keep it wet inside. It insures there is enough. The cells are well packed within the case and the capillary action will keep the cells moist to do the work needed. 

Just don't mount them upside down. 

Pete


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## steven4601 (Nov 11, 2010)

Is that cut up stand made by your faculty?


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## lnpurnell (Sep 27, 2012)

Are the CA cells sealed? I understand why the B or D position would put unesassary stress on the terminals, but does the gap at the top of the cell do anything else?

I understand the cell has a safety valve; if that is clear then the C position should be fine?

If the electrolyte does expand out of the cells could the cells be placed in the C position but with an angle of 5 or 10 degrees from the horizontal so the electrolyte doesn't flood the top of the cells?

Thanks!


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## lnpurnell (Sep 27, 2012)

I received a response from CALB in regards tot their CA cell and orientation. 

_"The reason why our cell can't mounted horizontally lies in the structure of the cell. Our rectangle cell choose lamination structure and lay horizonally would result in short circuit. If you insist on achieve this, you can choose pouch cell or round cell._

Oh well, looks like we will be going to cylindrical cells now for a floor mounted system,

Leigh.


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## MN Driver (Sep 29, 2009)

Fuuuuuuuuu#$%
That's no fun to see that the cell manufacturer I'm using give a specific reason why not to mount them the way that would let me fit as many cells as I want to in my car. Time to get out the tape measure and make some mock cells for the test fit all over again. *sigh* Fitting 100 CALB CA 60Ah cells seemed easy wiring them together, stacking them up, strapping them, then laying them in place. Now I'm not sure I'll be able to fit 100 of them and cutting the floor is not an option with my car.


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## lnpurnell (Sep 27, 2012)

Sorry to hear that MN Driver, 

It sucks that these cannot be mounted horizontally. I do believe that a tray mounted to the bottom of the body would have been the simplest to implement for a modified vehicle. I just don't want to fill my trunk and hood with cells, causes problems and looks crap.

Are there any good cylindrical cells on the market that are of a similar cost and spec to the CALB CA cells? 



Do you think CALB might be able to modify the cells to prevent the short circuiting happening? I was initially concerned with horizontal mounting and electrolyte leakage; I never thought of a potential short circuit issue.

Leigh.


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## dtbaker (Jan 5, 2008)

lnpurnell said:


> I received a response from CALB in regards tot their CA cell and orientation.
> 
> _"The reason why our cell can't mounted horizontally lies in the structure of the cell. Our rectangle cell choose lamination structure and lay horizonally would result in short circuit. If you insist on achieve this, you can choose pouch cell or round cell._



This is completely different than a response I got from them a while ago... the response I got was that they could be mounted horizontally without a problem. Only upside down is 'forbidden'.


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## lnpurnell (Sep 27, 2012)

dtbaker said:


> This is completely different than a response I got from them a while ago... the response I got was that they could be mounted horizontally without a problem. Only upside down is 'forbidden'.


This is what I am not sure of, I was very specific and worded the question to try and minimise confusion. The answer is technical and I double checked it with them. The person who I spoke to was the Europe Department, Sales Representative but she was based in China.

Leigh


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## dougingraham (Jul 26, 2011)

lnpurnell said:


> This is what I am not sure of, I was very specific and worded the question to try and minimise confusion. The answer is technical and I double checked it with them. The person who I spoke to was the Europe Department, Sales Representative but she was based in China.
> 
> Leigh


The answer you got is almost meaningless and contradictory to reality. If the cells will short if mounted on their side then they have no place in a high vibration high G force environment like a car. They would short when you go around a corner or when you are braking. The people who answered your question are not engineers and almost certainly have nothing to do with manufacture of the cells they are marketing. Manufacturing in China does not work like most other places where the factory is owned by the company that you buy the product from. Calb is a trading company that gets the product from one or more factories but most likely does not have any ownership of those factories. Asking technical questions of the marketing people would be like walking into Walmart and asking a checkout person about the color temperature of one of the LED bulbs they sell. Ok that is a stretch but not as far from reality as you might think.

People have been using prismatic cells positioned on their sides for several years without any issues. The particular brand is probably of little importance. The internal construction of a pouch cell is identical to a Prismatic cell for the purposes we are discussing.

If you have the cells why not take one and lay it on its side and cycle it a few times to assure yourself there won't be any issues. This would be more productive than trying to get answers from the marketing types through language barriers.


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## dougingraham (Jul 26, 2011)

lnpurnell said:


> I do believe that a tray mounted to the bottom of the body would have been the simplest to implement for a modified vehicle. I just don't want to fill my trunk and hood with cells, causes problems and looks crap.
> 
> Are there any good cylindrical cells on the market that are of a similar cost and spec to the CALB CA cells?


The GBS third gen cells would be ideal for mounting in a pan under the floor. Unfortunately they are available only in 200AH configuration. 36 of these with an AC-50 would be a really nice arrangement for a 2500 lb. or less car.

There are no cylindrical cells that are large enough to not be a real pain to wire up. And the available ones are quite a lot more expensive when you make a full size pack.


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## lnpurnell (Sep 27, 2012)

dougingraham said:


> The GBS third gen cells would be ideal for mounting in a pan under the floor. Unfortunately they are available only in 200AH configuration. 36 of these with an AC-50 would be a really nice arrangement for a 2500 lb. or less car.
> 
> There are no cylindrical cells that are large enough to not be a real pain to wire up. And the available ones are quite a lot more expensive when you make a full size pack.


Thanks for this dougingraham, i will use this. I am also going to push CALB to explain why they believe that short circuit is possible (I'd just like to get them to prove it now).

Leigh.


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## onegreenev (May 18, 2012)

lnpurnell said:


> Thanks for this dougingraham, i will use this. I am also going to push CALB to explain why they believe that short circuit is possible (I'd just like to get them to prove it now).
> 
> Leigh.


If you happen to squeeze that information out of them be sure to publish it.


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## lnpurnell (Sep 27, 2012)

I got a response from CALB again:

Q) Thank you for your response, you said that the CALB CA cell would short circuit if placed on the side, but I have had a technical team tell me that the CA cell is several pouch cells mounted together in a plastic enclosure. 

A) As I mentioned in my last email, our cell is laminated structure. I attached a pouch cell picture for your reference.

Q) What is the difference between the pouch cell and the CA cell? 
A) Pouch cell is soft package cell, CA cell belong to rectangle cell. (rectangle cell, cylindrical cell and pouch cell are three main lithium batteries).

Q) Where would the short circuit occur? 
A) We suggest the battery is stand up, if it's flat on the floor, electrolyte will leak and result in short circuit.

Q) If the CA cell was placed horizontally would there any other issues (such as electrolyte leakage)? 
A) That's the main reason, the possibility of electrolyte leakage increased if placed horizontally.

Q) Is CALB developing a pouch cell to use horizontally? would there be other issues? 
A) Our pouch cell is under R & D now.

From these answers I believe the main reason why they cannot lay horizontally are the connection tabs at the top of the cell, any electrolyte leakage shorting the circuit and this I believe is what they are mentioning. 

If this is the case; could we just place the cell on a 80 degree angle instead of 90? This would mean the cell is flat(ish) and would keep the electrolyte at the bottom of the cell. 

The only scenario where this may be an issue is if the car is parked on the sidewalk (curb) and the 10 degree angle is negated.

Thoughts?


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## jumpjack (Sep 9, 2012)

lnpurnell said:


> Q) Where would the short circuit occur?
> A) We suggest the battery is stand up, if it's flat on the floor, electrolyte will leak and result in short circuit.
> 
> Q) If the CA cell was placed horizontally would there any other issues (such as electrolyte leakage)?
> A) That's the main reason, the possibility of electrolyte leakage increased if placed horizontally.


Sorry for digging up this old thread, but these replies from manufacturer look insane...  

An automotive battery has mount orientation contraints? It is not a static battery, it must tolerate accelerations and vibrations!
And how is the electrolite supposed to "cause shortcircuits"? It MUST "shortcircuit" all plates, isn't it there for this reason? 
Additionally, I don't think prismatic cells actually have same assembly type of lead batteries, where you have multiple plates soaked in electrolite; you instead have multiple *sealed* cells made up of three layers: electrode, elecrolite, electrode.

From photos posted above I can't understand if there is actually a floating electrolite, removed to take pictures, or if it wasn't there from the beginning...


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## Moltenmetal (Mar 20, 2014)

My understanding is that the individual sealed pouch cells are swimming in electrolyte, which fills the handsome plastic case that encloses the pouch cell assembly and hence fills up the spaces between pouches. Presumably, the electrolyte is being used primarily for heat transfer purposes. That's a guess on my part.

There's a relief valve located between the terminals. If the cell is mounted upright, the relief valve will vent headspace vapour. If the cell is mounted in either horizontal orientation, the relief valve will vent electrolyte. That will eventually deplete the space between the cells of electrolyte, defeating whatever purpose it's there fore.

What they're talking about with respect to short circuiting, I have no idea.


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## Tesseract (Sep 27, 2008)

lnpurnell said:


> Q) Where would the short circuit occur?
> A) We suggest the battery is stand up, if it's flat on the floor, electrolyte will leak and result in short circuit....


Yes, I realize this is an old thread but someone had to dig it up anyway so here is what the Chinglish above is supposed to mean: 1) electrolyte is conductive; 2) placing a prismatic cell flat on its wide side increases the chances of electrolyte *leaking* from the cell; 3) leaked electrolyte will create a conductive pathway outside of the cell which could then cause a short circuit.



Moltenmetal said:


> ...Presumably, the electrolyte is being used primarily for heat transfer purposes. That's a guess on my part.


Sigh... no, the electrolyte is there to conduct current as well as electrically charged ions between the cell plates (anode and cathode).


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## onegreenev (May 18, 2012)

Moltenmetal said:


> My understanding is that the individual sealed pouch cells are swimming in electrolyte, which fills the handsome plastic case that encloses the pouch cell assembly and hence fills up the spaces between pouches.
> What they're talking about with respect to short circuiting, I have no idea.


No, the prismatic cells we use like the CALB SE do not have sealed pouches within the plastic case. They are wrapped but not in sealed pouches. They are also not SWIMMING in electrolyte. There is enough to saturate them and there is a little that rests on the bottom that does nothing but keep the environment damp. The bulk of the electrolyte is within the matrix of the cells. In other words the carbon is soaked in electrolyte and because the particles are so small the electrolyte stays in place due to capillary action. 

The Hi-Power Prismatic Cells do not have a top VENT. That cap is just a cap with an o-ring to seal it. 

Maybe the others do but if enough pressure were to be created Im sure it could vent around that o-ring seal. Now the interesting thing is that the terminals around the top are not actually sealed. They are tight against the terminal as it comes through the top. 

If you laid the cell on its side there would not be enough free electrolyte to even come close to touching the terminals. If it were laid flat the same would apply. But if you mounted it upside down the electrolyte could possibly leak around the terminals. 

The 100ah Cell contains two wrapped 50ah cells. 

http://onegreenev.blogspot.com/p/prismatic-dissection.html


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