whats about KOKAM??

[Lapwing]

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=9158&p=141552&hilit=+test+A123#p141552 Watch DocBass video. - unexpected result.

also...........

A123 safe lithium puncture test.

http://www.havina.fi/a123.htm

Kaido Kert kirjoitti 19.4.2007 kello 10.14:

On 4/19/07, Osmo S. <[EMAIL PROTECTED]> wrote:
So, I did a nail puncture test with fully charged cells at 60 degree
Celsius (140 F). Both Kokam 40 Ah High Power cell and A123 caught
quite an agressive fire, that lasted several minutes. That would
propably make the other cells of the pack to catch a fire also.

Woah, hold on there, A123 has repeatedly claimed that their cells wont
catch fire when punctured.
http://www.google.com/search?q=a123+nail+test
Are you saying you have proven otherwise ?

-kert

http://www.mail-archive.com/ev@listproc.sjsu.edu/msg07634.html


http://www.flying-gators-mac.com/docs/LI PO SAFETY HANDBOOK JUNE 05.pdf


Basically what I'm getting at is safetey of the products is all depends on a heap of unknows, as well as basic chemistries, and construction.

 

[Lapwing]

Basically what I'm getting at is safety of the products is all depends on a heap of unknows, as well as basic chemistries, and construction.

http://www.metricmind.com/audi/14-battery.htm is a good analysis.

Although I think that much Kokam in any one spot is nuts!

No way I would be stacking this up in my garage.

 

[Lapwing]

whats about KOKAM?

i just found only 2 topics about KOKAM...

i heard alot good stuf about KOKAM...why are kokam cells not used here?? they have very nice cells and they are not as expensive as BMI...

so, whats the problem with KOKAM cells??

worth doing a search on u-tube.

Use the keywords: kokam battery

I like proev.com
http://www.proev.com/WHistPgs/Hist0039.htm some good hands on here!

 

[liveforphysics]

BMI- This is a LiPoly battery using LiFePO4 chemistry. It is LiPo. Do you consider it to be a dangerous fireball waiting to happen because it's a LiPo cell?

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4053

 

[BMI]

I am not drawing conclusions. I have seen the results of the fires (numerous photos and videos sent to me) and have spoken to model aircraft owners who have had their aircraft go up in flames.
I looked into Kokam in some detail several months ago so by all means please correct me if they have come up with something safer in recent months which is not LiFeP04.
Sure I agree entirely that lithium manganese is much safer but why would you consider using a battery with a max cycle life of no more than 500 cycles compared to LiFePO4 which has a cycle life of 3-4 times that.

If Kokams (or similar Li-Po) are so safe please send me the MSDS for the cells showing their approval to be transported by air?

http://www.swe.com/MSDS/KOKAM/KOKAM_MSDS.pdf

Go to the page7 and 8. Yes they can be shipped by air. see also http://www.proev.com/WHistPgs/Hist0042.htm

So what is the separator material in BMI cells?

I could not find an MSDS for Lifebatt, or Headway or PSI yet. Any help apreciated. :lol:

Lapwing to answer your question BMI/Lifebatt and PSI cells use Polyvynilidene Difluoride (PVdF) which makes up 10% of the cell (by weight).

 

[BMI]

BMI- This is a LiPoly battery using LiFePO4 chemistry. It is LiPo. Do you consider it to be a dangerous fireball waiting to happen because it's a LiPo cell?

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4053

No this is clearly not what I would term a Li-Po cell. We are talking about the chemistry type and not method of construction so this clearly says it is LiFePO4 chemistry so is safe for a chemical makeup point of view.
We can use the cell voltage to categorise the safe cells from the less than safe cells. If the cell nominal voltage is 3.2-3.3V it is LiFePO4 so is safe. If the voltage is 3.6-3.7V it is more than likely not as safe. Of course there could be a bit of confusion here since Li-Mn cells also are quite safe even though they have the higher nominal voltage but my point would be why would you even consider using a cell with such a short cycle life (500-800 cycles at best) since everyone on this forum is so concerned with the price. The cost per cycle of good quality LiFePO4 is far cheaper even though the initial purchase cost may be higher.

 

[Anonymous]

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[RoughRider]

comon this BMI guy is talking bullshit all the way...

first he says, that kokam are not allowed to be shipped by airplane...BUT THEY ARE...

second, he says that his cell are sooooooo safey...but we have seen, that they are not...

and the kokam are soooo unsafe...look on all the test, that the kokams are going thru...

now, he is talking about the voltage of a cell...all cells about 3,6v are ALL ansafe...


WHAT A BULLSHIT...


what we have learnd IS...that ALL cell CAN burn...


PRICEINFORMATION on KOKAM

40AH = 120$ ==> 0,8$/Wh...

i am sure, that we can get lower that 0,5$/Wh on a bulk order...


VICTOR from metricmind is making very nice things...but it looks very heavy

 

[BMI]

Not sure if you're pulling your information out of a hat or what

Depth of Discharge 80% Calculated Life Cycle > 2500
http://www.kokam.com/english/product/kokam_Lipo_01.html

These are rated 20C discharge with peak up to 40C.
You seem to be assuming that all LiPo batteries are the same.

I am talking about Lithium Manganese batteries and in particular the only dedicated Li-Mn battery made for e-bike applications which is the Phylion battery. Of course there may be many others which I am not familiar with. I only know of the Phylion battery since it is the most widely used Li-Mn e-bike battery pack and through my discussions with one of the best known bicycle store owners in Australia who ended up being taken to court due to a dispute with a failed Philion battery pack he sold a customer (long story).
http://www.xingheng.com.cn/en/product.html
Once again I say why would you choose a battery with such a short cycle life?

 

[Anonymous]

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[RoughRider]

i guess so...

they send me NEW specsheets...

the 40Ah high energy cells are now good for minimum about 1200cycles...

 

[Anonymous]

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[BMI]

comon this BMI guy is talking bullshit all the way...

first he says, that kokam are not allowed to be shipped by airplane...BUT THEY ARE...

second, he says that his cell are sooooooo safey...but we have seen, that they are not...

and the kokam are soooo unsafe...look on all the test, that the kokams are going thru...

now, he is talking about the voltage of a cell...all cells about 3,6v are ALL ansafe...


WHAT A BULLSHIT...


what we have learnd IS...that ALL cell CAN burn...


PRICEINFORMATION on KOKAM

40AH = 120$ ==> 0,8$/Wh...

i am sure, that we can get lower that 0,5$/Wh on a bulk order...


VICTOR from metricmind is making very nice things...but it looks very heavy

We have to clearly separate a fire caused by a short circuit as opposed by the battery itself catching on fire due to its potentially hazardous chemical makeup. These are two entirely different things which appears to be where Roughrider is getting confused.
The last time I checked every one of the millions of laptop computer batteries which were recalled due to fires had a terminal voltage of 3.6V. The number of laptop batteries which are LiFePO4 chemistry (with cell nominal voltage of 3.2V) is zero, zilch, none! (Please correct me if I am wrong)
Kokam's were the batteries used in many of the e-bike battery fires which have occured (as in the link to the smoking battery I provided earlier).
Has anyone experienced a similar fire using a Ping, Headway, A123 or other LiFePO4 battery. I don't think so because it just can't happen.

Once again we have to understand the difference between an electric fire (caused by a short circuit) with a fire due to chemical makeup (due to reaction of free lithium metal with oxygen from the air) which is virtually impossible to extinguish once started. This later fire is a self sustaining fire. The electrical fire will soon go out in a LiFePO4 pack of its own accord once the cause of the short circuit is removed.

So I wonder why are Kokam's not as popular for e-bike packs as LiFePO4 packs (Ping, Headway, etc)?

 

[RoughRider]

@BMI
did you missed the post on side "2"...this car with LiFePo, that burns out??


what i think is, that KOKAM is unknowen jet and not so easy to buy...if you write a email to them you want get an answer...dont know why...

maybe, they just dont want to deal with "small" customers...

write a email to ping and you will get a reply very soon...

 

[BMI]

Does BMI represent BMI?

Yes I am proud to be the supplier of this high quality LiFePO4 battery to this customer. The information provided on the EE website is not in any way a part of or associated with BMI. It is entirely the customer's own personal website showing the entire conversion process from ICE to electric drive including the battery types/manufacturers this customer has chosen. I have no control over what information this customer decides to use on his website other than giving permission to freely display/publish technical data or photos I have previously provided (and which I provide to all my customers so they understand all of the technical aspects and specifications of BMI batteries so as to obtain the best performance and longest service life).

 

[BMI]

@BMI
did you missed the post on side "2"...this car with LiFePo, that burns out??


what i think is, that KOKAM is unknowen jet and not so easy to buy...if you write a email to them you want get an answer...dont know why...

maybe, they just dont want to deal with "small" customers...

write a email to ping and you will get a reply very soon...

I must of missed something Roughrider since I am not sure what you mean by "the post on side 2?"

Perhaps you are right and they don't want to deal with small customers. I can't say since I haven't had dealings with the company and don't know their policy of who they will/will not sell to.
All I can speak for is the way BMI conducts business with its customers. That is why I like being associated with BMI due to their friendly, customer focussed nature. BMI is just as happy to supply single cells or batteries to individuals as it is supplying large companies with battery products. I am more than happy to sell even individual cells to customers for testing so they can be happy in their own minds after performing their own tests before ordering complete battery packs or cells in larger quantities.
I really don't know how I could be more helpful thant that but I am always open to suggestions!?
It is often said that companies like A123 Systems and Valence Technology are "arrogant" since unless you want to place an order for several hundred thousand dollars worth of their products they won't even reply to your emails. Well thankfully BMI is nothing like that and is a much friendlier company to do business with. I wouldn't represent them it that wasn't the case!

 

[Anonymous]

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[BMI]

Does BMI represent BMI?

Yes I am proud to be the supplier of this high quality LiFePO4 battery to this customer

And the thread is about Kokam batteries. Not BMI. Not LiFePO4.

I agree. But I only answered a direct question which was asked of me.

To get back to this thread it would be helpful if there was a Kokam distributor or other representative who could answer questions regarding Kokam products.
......Calling anyone from Kokam!

 

[liveforphysics]

PRICEINFORMATION on KOKAM

40AH = 120$ ==> 0,8$/Wh...

i am sure, that we can get lower that 0,5$/Wh on a bulk order...

I'm interested in seeing what I could do with a factory direct price, not through metric mind, and for an order in maybe the $20k range.

If we could get the pricing down to something like $80 per 40Ah cell, that would be a pretty good deal. $0.54/Whr.

The beauty of these cells is low Ri, which means much less of the pack's energy is being wasted thermally, as well as no practical restrictions on current draw for an E-bike. For packaging, it would be so slick to have a stack of 40Ah cells in each side of pannier bags. No dead space in between them like round cells, simple and low reistance pack construction with 1P tabbed cells, and

LiFePO4 (BMI 10Ah cell)
193whrs per L (round cell's have deadspace, so this figure in a pack would be much lower than when I calculated it for a single cell)
101whrs per Kg


Kokam 40Ah cell
347whrs per L (no dead space in a pack)
174whrs per kg


So, using this battery technology, in practice I think it's safe to say the pack would be less than half the volume of a pack made from BMI cells, and about 58% of the weight. It would also appear to be cheaper than BMI cells, even at full retail price for a single cell from a vendor who of course has mark-up.


The Kokam batteries still can't match my non-safey LiPo pack on my E-bike though

50kW capable goodness in a light compact little package

 

[Lapwing]

@BMI

Well thankfully BMI is nothing like that and is a much friendlier company to do business with. I wouldn't represent them it that wasn't the case!

Would still love to see a BMI, MSDS sheet as required to airmail.

Anybody???

 

[RoughRider]

@lifeforphysics
if we you can get a price around 80$ per 40Ah cell...that would be very nice...

but, i send many email to the factory and they never answered any of them...i asked only for 50cells...maybe its a to small order to answer...

i got the prices from a german destributer...

maybe they only answer to email, that are written in korean???

any koreans on this board??


@BMI
you missed that??:

http://www.go-ev.co.uk/images/fire/index.html

http://www.metricmind.com/audi/14-battery.htm

i agree with you, that kokams customer relationship is not so good...

 

[RoughRider]

is DOCTORBASS interessted in testing this cells?

 

[miro13car]

let's read this MSDS carefully,
rather typical stuff for Cobal -based Polimer.
section10 - conditions to avoid:
heating above 60C , that's not really hot , that is evident how dangerous this cells are in hands of DIYselves.
One time I was also excited about energy density of this cells and how small 10Ah pack would be.
Authorised Distributor Kokam in Vancouver cooled me down and said that primary reason for not selling high power cells /except rc small cells/ in open to small DIY crowd is safety.
You can overcharge LiFePo all day long and what would happen?
At 60C I am sure nothing will happen to my LB/BMI cells, nothing will happen to Ping cells also, ask Dogman, he lives on desert.
Cobal based is Cobal based.
One thing is laptop battery protected with software-based charging/dischargin alogarithm, another thing is raw danger of say 20Ah of Cobalt based Polymer in hands of DIY selfer who himself decides on charger and on construction of charger.
M

 

[Anonymous]

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[BMI]

let's read this MSDS carefully,
rather typical stuff for Cobal -based Polimer.
section10 - conditions to avoid:
heating above 60C , that's not really hot , that is evident how dangerous this cells are in hands of DIYselves.
One time I was also excited about energy density of this cells and how small 10Ah pack would be.
Authorised Distributor Kokam in Vancouver cooled me down and said that primary reason for not selling high power cells /except rc small cells/ in open to small DIY crowd is safety.
You can overcharge LiFePo all day long and what would happen?
At 60C I am sure nothing will happen to my LB/BMI cells, nothing will happen to Ping cells also, ask Dogman, he lives on desert.
Cobal based is Cobal based.
One thing is laptop battery protected with software-based charging/dischargin alogarithm, another thing is raw danger of say 20Ah of Cobalt based Polymer in hands of DIY selfer who himself decides on charger and on construction of charger.
M

That is one of the great features of LiFePO4 cells. They are much safer to use than other lithium chemistries in high temperature environments. I agree that 60 deg C is not that hot. LiFeP04 (unlike Li-Po) can be used safely at temperatures as 100 deg C. We all know how hot boiling water is and it is still safe at that temerature! In fact from tests performed on BMI/LB cells they don't actually vent until between 110-120 deg C.
Even the Sandia lab tests found this and from their own temperature testing they found-

"6) Over Charge Abuse Test at 1C rate to 12V
Results: Cell vented at 111C at 11V - Open-circuit at 120C - No fire - Max Temp was 160C"

When all is said and done you can't get any safer batteries than LiFePO4 (at least in 2009, who knows what will be available in the years to come)