A123 20AHr Pouch Cell Battery Build & Info Thread

[etriker]

No mention of the USA tab welding issue?

It says they hid that from investors ?

 

[Doctorbass]

Guys.
I just dug through a lawsuit file against A123, on the AMP20 pouch cells. Downloaded the original document from stanford.edu.

It's 66 pages long. Here is my take away:

1. The original AMP20 is made in Korea. The Korean cells seemed OK. The US operation was setup later with Korean process.
2. Majority of the AMP20 cells made in US did not meet the quality control spec. Using a US AMP20 cell is like playing the Russian roulette.
3. A123 knew they had a quality control problem and covered it up.
4. The US made AMP20 cells may have bad electrode coating.

it's good to know...

But from all the 180 cells i tested individually, all 180 was with in 2% of the original specs and have a exellent RI and capacity uniformity over all teh cells.... and they are from USA and boughht from Victpower.


I think that if they pass these Doc test it worth playing russian roulette! :wink:

Doc

 

[etriker]

These must all be scrap cells being sold from China.

They bought a large amount of them for scrap prices and found some good ones to sell in the lot and sold them to you ?

I would not expect the supply of good ones to last for long.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=48132#p708450

 

[Doctorbass]

DOCTORBASS Zero Motorcycle 2kWh battery upgrade using A123 pouchs

Yes it's finally time for me to begin that great project for extanding the range of my Zero motorcycle 2011 ! The idea is to begin by adding a 2kWh pack made of 16s2p A123 pouchs and to quick install it on my zero OR on my KMX trike for about 100km range.. or on the Zero for about 40km more range.

The goal is to have a battery pack that is strong and will protect cells from hard vibration, puffing, puncture, cold etc.... adn that will be as strong as if it would be welded( I used flat 8-32 screw and Dp-420 off white epoxy )

-Testing all 34 A123 pouches cells in RI and Capacity at medium rate 34 cells tested. CHECK
-Preparing all cells for the Agniusm kit: CHECK
-Assembling all cells in the AGNIUSM kit: CHECK
-Building the aluminum box to be strong, water tight and welding free: CHECK
-Preparing the 6 AWG cables for connnectin to cells: CHECK
-Installing the Signalab 16s BMS and upgrading it for 400A: PENDING

Here is some pictures for you guys :wink:

Doc

 

[Doctorbass]

I saw a thread that Methods started that is interesting. It suggest using Fets ( solide state) instead of contactor or relay and to solve alot of existing problems we have.

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=48166

The battery is finished and i am at the point where i need to connect the Signalab 16s BMS to the battery but it's a stock 40A bms. the first idea i had was to use 4 car relay with coil in serie to get an equivalent 48V coul that would be driven by the BMS output and have the contact in parallel. I would het about 80A x 4 = 320A max and have 160mA of current to drive the relay that wold also be activated with a 12V relay that conect to the Zero 12V system so once the zero is ON, the relay let the 48V out of the BMS to go to the relay coil and activate them to conduct up to 320A. this desing is simple but will draw 170mAh every hour... for nothing... and these 1 cu inch car relay just dont enter in the battery case i designed...

Then i thought abot using my EV-200 that would be driven by a 48V to 12V dc-dc where the 48V is from the BMS output... but again the contactor is big and draw 1.9W for nothing... i could also add a 12v relay in serie that would be active only when the zero is ON, but it add some connections between the battery and the motorcycle.. and also the EV-200 is too big.. i would need to install it out of the battery wich is not esthetic.

Then i thought about adding some 4110 mosfet to the signalab bms and use it as is but with more parallel mosfet... i remember that i was able to drive like 20A continuous with minimal heat sink at 58V for only one mosfet...! so for 300A+ i would need 15 of them... and if my controller have regen i woul need to double that !

OK.. wait a minute... 300A is for burst and the average is more like 50-60A on my Zero.. at least... this is what i have recorded with my Cycle analyst... so this mean i could just install like 10 of them for having 100A cont and 400A burst? safely? Hmm ... will see with the update on his thread.

Doc

 

[April]

I snagged one of the battery termination kits that ambroseliao purchased and described a couple of pages back from Nancy at OSN Power. I find it well made and would have used the same words he did in describing it. Using his picture, it is the same kit:

I bought it because my scratch design was 90% similar to theirs in form and function, and it sure saved a lot of work on the milling machine!

What I will add is Nancy from OSN was just a great person to deal with. Her english is 100% and I found her extremely helpful and responsive. Kit came a little over a week from my purchase date. All in all an A++ transaction for me.

Bigmoose, These kit look interesting due to the easy and fast way to assemble the pouches. Do you agree with me that it would be only recommanded to use with low to medium power ?

There is two importants points i think that make them more risky for high amp ( let say 50+ amp)

First , I believe that the pressure uniformity on the tab width is weak. The two screw at each end will make the conductive top bar to bend and not have the same pressure on the center as the pressure on the sides near the screw. There is no screw to push to the cell tab to all their width. so the contact is not made on 100% of the tab width and i think it is way lower than what it look like. if you torque more the screw, it might get worst.

And, in electrical engineering, having high current conductor in sandwich between plastic and metal is not a good idea due to the possibility that the plastic soften depending on the temperature, reducing the pressure on the cell tab and increasing the contact resistance. And as the plastic soften, as the contact resistance goes higher and that loop could result in hot spot or melt plastic and even create a fire if the current is sustained. cheap chineese plastic are not fireproof i think. That kind of sandwich was what few years ago have made one of the Hymotion plug-in hybrid Prius battery to burn to the ground due to bad electrical contact desing with a screw torque between metal conductor and plastic battery case.

That’s why I preferred to buy some of the kit that Agniusm made wich are excellent to me but are a bit more expensive and require more assembly time, but I think it worth anyway.

The agniusm kits are not using plastic but FR4 ( pcb fiberglass material) with does not soften at the temp range the battery tab can reach, it is more hard material. And also the sandwich conections is made with two aluminum bar and 3 screw that spread perfectly the pressure along the cell tab width wich guaranty the electrical resistance to keep low and stable.

What do you think?

Doc

Hi Doc,
This is April or Nancy from OSN Power.
About the kit, I reported your worries to our technicians.

For the kit, only the general postive and negative end carry the high current, other matal plates mainly to create the clamping pressure, so no worry about the soften of the plastic plates.

And we have tested the clamping pressure of the kit, there is no problem.

The material of the kit is a kind of special epoxy resin, not common plastic, and the studs and screws are copper.

On the general postive and negative end, there are two special matal bars sandwiched together, which is used for high current.

By the way, we are now developping a new special matal bar on the general postive and negative end to update the kit especially for high current.

 

[Doctorbass]

Hi Doc,
This is April or Nancy from OSN Power.
About the kit, I reported your worries to our technicians.

For the kit, only the general postive and negative end carry the high current, other matal plates mainly to create the clamping pressure, so no worry about the soften of the plastic plates.

And we have tested the clamping pressure of the kit, there is no problem.

The material of the kit is a kind of special epoxy resin, not common plastic, and the studs and screws are copper.

On the general postive and negative end, there are two special matal bars sandwiched together, which is used for high current.

By the way, we are now developping a new special matal bar on the general postive and negative end to update the kit especially for high current.

Hi April,

I understand your explanations but the problem is that the flat bar you use and the only two screw with one on each end make the flat bar to bend and not have the pressure to all the width of the surface.

I made a drawing to explain what i mean. Please consider that you might not see the bending wby eyes but in high electrical current, a simple variation of pressure mean alot of diference and your proposed desing can not guaranty that pressure along all the width of the cell tab

 

[megacycle]

The current is carried through the whole pack too April, so just improving the end connections wont do.
Agniusm came up with a good simple method that would fix it a few pages back.

 

[etriker]

Guys.
I just dug through a lawsuit file against A123, on the AMP20 pouch cells. Downloaded the original document from stanford.edu.

It's 66 pages long. Here is my take away:

1. The original AMP20 is made in Korea. The Korean cells seemed OK. The US operation was setup later with Korean process.
2. Majority of the AMP20 cells made in US did not meet the quality control spec. Using a US AMP20 cell is like playing the Russian roulette.
3. A123 knew they had a quality control problem and covered it up.
4. The US made AMP20 cells may have bad electrode coating.

it's good to know...

But from all the 180 cells i tested individually, all 180 was with in 2% of the original specs and have a exellent RI and capacity uniformity over all teh cells.... and they are from USA and boughht from Victpower.


I think that if they pass these Doc test it worth playing russian roulette! :wink:

Doc

What do you think my chances of getting 180 out of 180 good cells from Victpower are ?

I don't know the secret handshake.

 

[bigmoose]

Doc, sorry I didn't check back in and missed your comment/question. Yes, I agree that the stock OSN kit is only good for low power...like you said something around 50/60 ish amps, and I fully agree with the metal cap strips bending as shown in your drawing. For high power, like you run, there should be a steel insert under the tabs, and one over the tabs with a machined in bowed surface (convex surface) on both surfaces touching the tabs for proper compression. I would put 0.007 to 0.010 inches ~0.2mm of "bow" on each part and tailor the thickness so that it goes flat under the compression of the screws. The clamps do not need to be made of highly conductive material.

 

[etriker]

Doc, sorry I didn't check back in and missed your comment/question. Yes, I agree that the stock OSN kit is only good for low power...like you said something around 50/60 ish amps, and I fully agree with the metal cap strips bending as shown in your drawing. For high power, like you run, there should be a steel insert under the tabs, and one over the tabs with a machined in bowed surface (convex surface) on both surfaces touching the tabs for proper compression. I would put 0.007 to 0.010 inches ~0.2mm of "bow" on each part and tailor the thickness so that it goes flat under the compression of the screws. The clamps do not need to be made of highly conductive material.

Some of these cells may well be ok for low power use.

The reason A123 sold them for scrap may be they fear they would fail at high currents because of quality control problems ?

I like to use recycled cells too but expecting these reject scrap cells to do high current ? ? ?

 

[bigmoose]

Just for clarity, I was commenting on the OSN cell clamping "kit" that has been sold, not the cells themselves.

I just finished reading the court documents against the A123 USA production for Fisker and the allegations are quite damming. I am glad that I am storing my A123 pouches in a covered trailer "out back" of the house.

That said, the issues seem to be in two major areas, moisture contamination and the defective sonic welding machine/procedure. I will throw an opinion out that the defective sonic weld should be apparent with measurement of the cell's internal resistance. The moisture issue may not be externally measurable until the cell degrades early or goes "poof".

I am really upset that an American company allegedly did this, especially one that got tons of government grant money to develop these cells over the years. If the allegations are correct, these million dollar a year executives should be stripped financially and be put behind bars...they knoweth what they dooith.

 

[agniusm]

Doc, I mean, jee I'm speechless. Those black and red wires just makes your pack work of art. congrats from the heart.

 

[etriker]

Just for clarity, I was commenting on the OSN cell clamping "kit" that has been sold, not the cells themselves.

I just finished reading the court documents against the A123 USA production for Fisker and the allegations are quite damming. I am glad that I am storing my A123 pouches in a covered trailer "out back" of the house.

That said, the issues seem to be in two major areas, moisture contamination and the defective sonic welding machine/procedure. I will throw an opinion out that the defective sonic weld should be apparent with measurement of the cell's internal resistance. The moisture issue may not be externally measurable until the cell degrades early or goes "poof".

I am really upset that an American company allegedly did this, especially one that got tons of government grant money to develop these cells over the years. If the allegations are correct, these million dollar a year executives should be stripped financially and be put behind bars...they knoweth what they dooith.

That ones with welding problems have showed up being sold in China and they were recalled.

A123 dumped made in the USA recalled battery cells in China ?

It is against the law to sell recalled products in the USA so they sold them to people in China and they sold them back to us ?

 

[steveo]

DOCTORBASS Zero Motorcycle 2kWh battery upgrade using A123 pouchs

Yes it's finally time for me to begin that great project for extanding the range of my Zero motorcycle 2011 ! The idea is to begin by adding a 2kWh pack made of 16s2p A123 pouchs and to quick install it on my zero OR on my KMX trike for about 100km range.. or on the Zero for about 40km more range.

The goal is to have a battery pack that is strong and will protect cells from hard vibration, puffing, puncture, cold etc.... adn that will be as strong as if it would be welded( I used flat 8-32 screw and Dp-420 off white epoxy )

-Testing all 34 A123 pouches cells in RI and Capacity at medium rate 34 cells tested. CHECK
-Preparing all cells for the Agniusm kit: CHECK
-Assembling all cells in the AGNIUSM kit: CHECK
-Building the aluminum box to be strong, water tight and welding free: CHECK
-Preparing the 6 AWG cables for connnectin to cells: CHECK
-Installing the Signalab 16s BMS and upgrading it for 400A: PENDING

Here is some pictures for you guys :wink:

Doc

Hey Doc

Can you post a discharge test?

maybe at 100 amps & 200amps..

would like to see your voltage sag...

-steveo

 

[etriker]

So why did they not destroy the recalled A123 cells before they sold them for scrap ?

This is a disclaimer from Dan at A123 ?

http://endless-sphere.com/forums/viewtopic.php?f=31&t=41354&start=50#p635220

He knew these recalled cells were being resold ?

 

[etriker]

This is what they are up to now ?

http://info.a123systems.com/blog

Hybrid approaches with two batteries in parallel

Parallel a different battery chem with A123 cells to allow each battery to play to its strengths in the system ?

 

[Doctorbass]

Hybrid approaches with two batteries in parallel

Parallel a different battery chem with A123 cells to allow each battery to play to its strengths in the system ?

That's what i'm doing with my Zero! 14s LiMn in parallel with 16s LifePO4. and.. the LifePo4 will take the regen current and the stock LiMn will not. ( my plan)

Doc

 

[Doctorbass]

DOCTORBASS Zero Motorcycle 2kWh battery upgrade using A123 pouchs

Yes it's finally time for me to begin that great project for extanding the range of my Zero motorcycle 2011 ! The idea is to begin by adding a 2kWh pack made of 16s2p A123 pouchs and to quick install it on my zero OR on my KMX trike for about 100km range.. or on the Zero for about 40km more range.

The goal is to have a battery pack that is strong and will protect cells from hard vibration, puffing, puncture, cold etc.... adn that will be as strong as if it would be welded( I used flat 8-32 screw and Dp-420 off white epoxy )

-Testing all 34 A123 pouches cells in RI and Capacity at medium rate 34 cells tested. CHECK
-Preparing all cells for the Agniusm kit: CHECK
-Assembling all cells in the AGNIUSM kit: CHECK
-Building the aluminum box to be strong, water tight and welding free: CHECK
-Preparing the 6 AWG cables for connnectin to cells: CHECK
-Installing the Signalab 16s BMS and upgrading it for 400A: PENDING

Here is some pictures for you guys :wink:

Doc

Hey Doc

Can you post a discharge test?

maybe at 100 amps & 200amps..

would like to see your voltage sag...

-steveo

Hello steveo, Yes i will do.. I have a 0.7 ohm 2000W no ceramnic load resistor that i can drop in the water so 5300W at 100A and 10600W at 200A should work well. I have a Kelly 72V 600A controller so i will use it to test. that will allow me to modulate the current easy without any big flash.

Also, I have already tested the resistance of each cell including their connections and i'm getting about 1.0 miliohm per cell including the connection resistance loss so 16 miliohm for 16s1p... will probably drop to 8 miliohms for 16s2p.. at 50% SOC
Will test soon.

Doc

 

[dnmun]

beautiful work doc. simple and elegant.

i had previously recommended a thicker clamping bar on the OSN, but for those who have a set to play with can you tell if it is possible to drill a hole through the assembled clamp and tab and put a screw through with a nut and flat washer on the backside to clamp in the middle to distribute the clamping force?

or maybe drill and use a pop rivet with a washer on the underside to capture the nipple sticking through and have a wide enuff seat to clamp the middle of that bar? or add a steel bar on top of the copper clamping bar?

 

[bigmoose]

If anyone is interested in, or needs some self cinching nuts for use with PCB's, I bought a 1,000 in US 4-40 thread (KF2-440 zinc plated steel) and 1,000 in US 6-32 (KF2-632 zinc plated steel) thread of the self cinching nuts in the attached pdf. If you need some let me know and I'll bag some up and put them on my pieces parts site. I had to buy that many to get some for my own use. I'll never use the purchase quantity and am willing to bag them out if it will help with battery and pcb builds.

Edit: If your interested, tell me how many should be in a bag. ... and forgot to add the pdf.

 

[Doctorbass]

beautiful work doc. simple and elegant.

i had previously recommended a thicker clamping bar on the OSN, but for those who have a set to play with can you tell if it is possible to drill a hole through the assembled clamp and tab and put a screw through with a nut and flat washer on the backside to clamp in the middle to distribute the clamping force?

or maybe drill and use a pop rivet with a washer on the underside to capture the nipple sticking through and have a wide enuff seat to clamp the middle of that bar? or add a steel bar on top of the copper clamping bar?

Yes adding a pop rivet or a screw with nut and washer in the middle of the bar should improove the OSN desing for higher current.

Doc

 

[countermeasure]

Doc. Very impressive build.

A couple questions.
1. What are those blue sheets lining the aluminum case? Foam? Insulation?
2. Are those yellow ring connectors crimping connectors used in the automotive industry?
3. What are those molex connectors on the right hand side of the picture for?
4. What sizes are the parallel cabling and output cabling?

 

[Doctorbass]

Doc. Very impressive build. THANKS :wink:

A couple questions.
1. What are those blue sheets lining the aluminum case? Foam? Insulation? Yes it's foam for insulation and the white sheet is fiberglass for electrical insulation form the conductive aluminum in case of intense vibration and short circuit
2. Are those yellow ring connectors crimping connectors used in the automotive industry? Yes these are for 12-10 AWG wire from automotive industry
3. What are those molex connectors on the right hand side of the picture for? These are the BMS cell level connector for cell monitoring and balance These come with the Agniusm kit.
4. What sizes are the parallel cabling and output cabling? These parallel cabling are 10AWG 200 degree C silicone wires from turnigy and the output wires are 6AWG flexible wire from industrial supply

Doc

 

[vodk1c3]

The best build I can remember. If mine is half as good as this build I will be really happy. Good job!