A123 20AHr Pouch Cell Battery Build & Info Thread

[999zip999]

Hard call as if I'm going to take my drutledge build pack apart to check code. But if I do ??
The drutledge build is strait forward and is a puzzle of 123 or abc. Just take your time and have space it's just a clean pluzzle by the steps. Thanks. Sing it Michelle
Oh. yes mine kick ass at 72v 30amp. 28-30 mph. Hay I'm on the street or P.C.H so low key.
Drutledge how did you know to use the big peices of alumiun for heat shink and spacer's great Bro.

 

[ambroseliao]

Pressurised container? Nitrogen gas? You have to have some imagination to come up with such ideas. The question is how you gonna make it happen? To me it sounds like total absurd. I dont know why people want to reinvent the wheel? A123 shows you how to do it plane and simple. Make pressure plates and strap it. The only thing needed is to figure out method of measuring compression force.
I have asked here but no one who received free samples of oem pressure plates have not posted single line of measurements. This could be replicated and tested but most go on asking questions that were ansvered, posting ideas which are "Alice in wonderland" theme. Maybe I woke up on the wrong foot or the solution to the issue isn't moving anywhere..

I didn't see this msg from Agnius. Here are some detailed photos and measurements of the end plates that W9BK sent out.

It's 9.25" tall you can see the rubber piece that covers the A123 cell area.


6.5" wide


22.6mm or 0.89" thick. The rubber pieces are approximately 1/8" thick or 3.2mm thick.


There are metal tubes embedded in the plates for reinforcement so that the metal bands don't crush the ends!


These are really beefy plates! Here you see them placed on top of each other.

 

[agniusm]

Pressurised container? Nitrogen gas? You have to have some imagination to come up with such ideas. The question is how you gonna make it happen? To me it sounds like total absurd. I dont know why people want to reinvent the wheel? A123 shows you how to do it plane and simple. Make pressure plates and strap it. The only thing needed is to figure out method of measuring compression force.
I have asked here but no one who received free samples of oem pressure plates have not posted single line of measurements. This could be replicated and tested but most go on asking questions that were ansvered, posting ideas which are "Alice in wonderland" theme. Maybe I woke up on the wrong foot or the solution to the issue isn't moving anywhere..

I didn't see this msg from Agnius....

Thanks Ambro. Very good for you to jump in. Thanks for the pictures and info but if i could just ask for the main measurement i need. It is for the strap slots. bottom up to the strap slot-strap slot width; top down to the strap slot. Much appreciated.

 

[wb9k]

Ambrose,

The steel bushings in the endplates are for bolting the module down inside a pack. There are a couple different styles. Modules can lay vertically (bus bars on top) or on either side horizontally. Yours are for vertical mounting. You should add a shot of the terminal backings. The end bus bar (whichever side it's on) folds down over this and you bolt your cable right into the endcap, sandwiching the bus bar.

 

[ambroseliao]

Here are some measurements and observations on the A123 compression end plates.

Sorry for the mix of metric and imperial. The slot for the band on the compression end plate is just enough for a half inch band. The slot where the band sits is angled and is proudest in the middle of the plate. You can see this in the close up photos. The last shots are of the holes on the sides where if these were for vertical mounting, the two holes would I assume be open and would have the embedded steel tubes. Is that right w9bk?

Thanks again to W9bk for sending me the plates.

 

[ambroseliao]

Ambrose,

The steel bushings in the endplates are for bolting the module down inside a pack. There are a couple different styles. Modules can lay vertically (bus bars on top) or on either side horizontally. Yours are for vertical mounting. You should add a shot of the terminal backings. The end bus bar (whichever side it's on) folds down over this and you bolt your cable right into the endcap, sandwiching the bus bar.

Thanks for the clarification of my colorful post! Here's a photo of the terminal backings...

 

[agniusm]

Thank you for taking time doing this.

 

[ejonesss]

that's another thing the grades.
i know this from the solar cells but can it apply to battery too.

grade A is perfect quality.

grade B is cosmetic imperfections like scratches or polishing swirls stuff that does not effect the performance or function.

grade C is where there is damage that effects the performance or function like chipped corner a crack that lets moisture into the solar cell/panel.

These cells are readily available and are on sale at the A123 website for the B-grade for about $5 ea.

Note: we have reasonable assurance that the so called B grade are M1-A production to the previous spec. The new production are M1-B with a slightly higher Ah rating.

 

[oatnet]

I took this for agniusm last weekend, but just now getting in front of a computer to upload. Ambrose took much better and varied pics, but this does show the straps and ther dimension.

-JD

 

[agniusm]

So just to sum up the active area that needs compression is 297^2cm. Applying 15psi pressure means 1.05kg per 1^cm or 313kg on the whole surface of the cell. So using Interlink 400 series FSR sensor should give us output of 1+kOhms. It would be hard to stack 313kg on top of such small are, what about modifying hydraulic automotive jack with manometer and then jacking it up against unmovable object like concrete ceiling to 1bar. If recheck is not needed this could be used as a gauge to jack and strap :

I wander if that could work? Me needs to test this

 

[deVries]

So just to sum up the active area that needs compression is 297^2cm. Applying 15psi pressure means 1.05kg per 1^cm or 313kg on the whole surface of the cell. So using Interlink 400 series FSR sensor should give us output of 1+kOhms. It would be hard to stack 313kg on top of such small are, what about modifying hydraulic automotive jack with manometer and then jacking it up against unmovable object like concrete ceiling to 1bar. If recheck is not needed this could be used as a gauge to jack and strap :

I wander if that could work? Me needs to test this

Whether it works or not 15psi is probably far too high a pressure to be using for ebike applications. Why? W9BK has already stated in this thread that 10psi is considered adequate from his findings, AND that some A123 people have suggested 5psi is adequate.

Ebike power draws are very small with 20Ah pouches vs automotive testing, so it stands to reason that 5psi is VERY LIKELY to work just fine for ebike applications.

Why do more? You are likely way over designing for the application at hand needlessly complicating this matter when a lighter weight and simpler solution is at hand -5psi.

 

[wb9k]

More is better, for multiple reasons. If it's reasonably achievable, you should go for it.

 

[deVries]

More is better, for multiple reasons. If it's reasonably achievable, you should go for it.

Thanks for the response, and I stand corrected that more is better. Hmmm...

 

[ejonesss]

so can we get away with putting the pressure plates in and just shrink wrapping the packs like the rc lipo packs are done?

Ebike power draws are very small with 20Ah pouches vs automotive testing, so it stands to reason that 5psi is VERY LIKELY to work just fine for ebike applications.

Why do more? You are likely way over designing for the application at hand needlessly complicating this matter when a lighter weight and simpler solution is at hand -5psi.

 

[deVries]

so can we get away with putting the pressure plates in and just shrink wrapping the packs like the rc lipo packs are done?

No, unless it can give at least 5psi applied equally over the large flat surface area of the cells. W9BK just posted, see above, that more PSI above 5psi is better IF it is reasonable to do in the design for an ebike.

On the other hand, Doctorbass is using no high-pressure techniques, and I think he has a great solution that seems to work well so far. Doctorbass has not changed his viewpoint that I'm aware of, since he posted his ideas just recently. I'm certain he follows this thread, so he can post to the contrary at any time.

Personally, I think IF 5-10psi applied pressure is equal over the surface area, then I believe it will work just fine for ebikes. This is just my opinion. No one knows for certain, since no data or testing is given to find out.

 

[ejonesss]

if someone could build a pack and run it at ebike loads such as running 1 to 100 amps and try to find the spot where puffing starts that would help.

 

[deVries]

if someone could build a pack and run it at ebike loads such as running 1 to 100 amps and try to find the spot where puffing starts that would help.

:lol: :lol: :lol:

At current prices of $70/cell maybe A123 labs can do it for us, but they already won't share the data for the automotive research. I don't think they're likely to help-out unless you're buying 1,000's of these cells. Plus, the experiment has to be a worthy one to even consider it in the first place.

 

[ejonesss]

but yet http://www.buya123batteries.com/AMP20M1HD_A_Lithium_Ion_Prismatic_Pouch_p/amp20m1hd-a.htm you can buy them.

so sink $1400 +65 for shipping and you can test them.

another thing you could do is try the

http://www.ebay.com/itm/High-Quality-3-2V-20Ah-LiFePO4-Prismatic-PHEV-EV-E-REV-Rechargeable-Battery-Cell-/400556658146?pt=LH_DefaultDomain_0&hash=item5d43098de2

$30 their claim make me believe they are just b grade and ig the battery grading system is the same as solar cells then it is just cosmetic defects such as wrinkles in the pouch or color issues from being exposed to the sun say they was next to a window.

same goes for

http://www.a123rc.com/goods-468-Excitingly+Powerful+A+123+20ah+PRISMATIC+CELLS.html at $50.


if no one can or is willing to sacrifice some money then i am considering sacrificing money in witch case

does anyone know what cba is used by the es community for load duration testing?




quote="deVries"]

if someone could build a pack and run it at ebike loads such as running 1 to 100 amps and try to find the spot where puffing starts that would help.

:lol: :lol: :lol:

At current prices of $70/cell maybe A123 labs can do it for us, but they already won't share the data for the automotive research. I don't think they're likely to help-out unless you're buying 1,000's of these cells. Plus, the experiment has to be a worthy one to even consider it in the first place. [/quote]

 

[deVries]

if no one can or is willing to sacrifice some money then i am considering sacrificing money in witch case

does anyone know what cba is used by the es community for load duration testing?

Hey, if you can, then that would be great and welcomed. I'm sure people will help share some test ideas, so you can get the best results with better experiments.

As far as CBA goes, I suggest researching Doctorbass and his test setups. He has posted many YouTube videos that are excellent and even some testing these A123 20Ah cells too. There are many threads to be found by Doctorbass and others using the CBA, etc.

Use the ES search engine with good key words, and you will target those threads quickly. Don't forget to plug-in Doctorbass in the user name field too. This will narrow your search to get to his expert threads.

 

[megacycle]

If the correct operation of the cells is reliant on knowing the correct operating pressures and A123 are selling them, through a reseller, or even though indirectly, to the public, because they'd know this, there must be rules somewhere regarding providing this type of almost crucial information, to the public domain, in data sheets.
Why should it be top secret IP? and being flogged to anyone, unless they just don't know themselves, which could be .
Actually, be off looking for a contact email address.
Found the A123 contact address and in a few words stated i'm concerned about premature death/cell ruputures, due to this issue, please provide info or indicate where info is. Regards

 

[megacycle]

Got a confimation of recieved email, hopefully we'll get the info, fingers crossed, never works for me :?

 

[agniusm]

So I've got first puffer:

Cells were sitting there balancing. No overcharge or over discharge. was used once at 50A discharge rate. Kept at 18-22C temp. No punctures.

 

[wb9k]

Was the cell under compression when used at 50A? How long was it sourcing that kind of current? The black spots at the edge of the cell suggest anode shorted to pouch. Who was the source of the cell? I assume you did not buy from A123.

Measure voltage between the cathode and pouch. You'll have to pierce the insulation a bit, but if there's charge in the cell, I bet you'll see the bulk of the total voltage between the cathode and pouch.

 

[agniusm]

Was the cell under compression when used at 50A? How long was it sourcing that kind of current? The black spots at the edge of the cell suggest anode shorted to pouch. Who was the source of the cell? I assume you did not buy from A123.

Measure voltage between the cathode and pouch. You'll have to pierce the insulation a bit, but if there's charge in the cell, I bet you'll see the bulk of the total voltage between the cathode and pouch.

Cell wasn't under compression when used but it was 6km when i tested my cargo bike functionality. Cell is at 3.41V at the moment. Cell was bought from victpower 2 years ago, no one could obtain them legally, even Mavisen was not selling them at that time.
So i guess it's a manufacturing error? Was NASA talking about this if i remember correctly?!
I will test with the meter as you suggest but which side to puncture? Is it the side with markings? I don't know if anode layer is at the top(marking side) or bottom.
I was gonna get it overcharged and make a vid for reference, last good bit of information she still has to offer

 

[wb9k]

Measure voltage from the cathode tab to the bag. You can puncture the bag anywhere, but it's best to use a SMD probe to puncture the roll along the edge. You don't want to puncture the electrode stack, that would ruin your measurement. Easiest to puncture the roll at an upper corner. Any voltage you measure should fall off rapidly from where it starts. It's normal for the pouch to charge capacitively, but if the voltage holds steady above a Volt or so it's got a problem.

However, I've never seen that defect cause a cell to puff up. Drawing 2C from an uncompressed cell for several minutes could definitely do that.