whats about KOKAM??

[RoughRider]

@BMI
PLEASE STOP FOOLING THE PEOPLE...

what you are writing is just absurd...

here we have the specs of YOUR cells:

http://lithbattoz.com.au/index.php?page=battery-cells

so there we have a discharge temperaturerange of : -10 - 55°C...
if your cells are SOOOOO safe, why are you just go to 55°C??


here we have the specs of a kokam 40Ah high energy cell:

http://kokam.com/product/product_pdf/high_power/PL-202_SLPB100216216H_40Ah_Grade.pdf


well...the dischargetemprange is: -20 - 60°C
its BETTER than yours...

 

[BMI]

You are looking at the recommended charging and discharging temperatures for normal use. Where is anything said about actual SAFE operating temperatures which are way above normally experienced temperatures?
The actual destruction tests showed the BMI cells won't vent until easily over 100 degrees. We are talking about extremes and what happens to cells when you push them past their limits. Not recommended operating conditions (from the specifications which are listed for the everday user).

 

[RoughRider]

well, when the kokams are good for 60°C on "normal" conditions...they are sure good for more than 100°C on extrem conditions...

safety test of kokam shows, that they can take 150°C with no damage...

the link is allready posted...so just klick it and watch...

 

[Anonymous]

.

 

[BMI]

Hi,

Well after reading this thread, gess what i continu to use my Konions i pretty satisfy with them, size, weight and power!

P.S. BMI how much for 67 Volt 60 Amps pack, with BMS, no charger in CAD ?

Good day all!
Bikeraider

I am sorry Bikeraider but since the HPS packs use the 40138F1 cells all packs above 48V come in 10Ah blocks. Therefore the batteries must be connected in parallel to provide the desired Ah capacity. We have a 48V pack and then a 72V factory pack but no 67V pack I am sorry.
The packs are available in either of two forms. The first is the regular HPS factory pack and the second is a "EV Designers Pack". The designers pack is essentially a factory battery but without the security screws fitted. This allows the owner to either fit the screws so they have a regular HPS battery or alternatively they can remove the battery panels so they can gain access to the individual cell connections. In this way you can remove cells and rebuild the entire pack into a more suitable shape which will better fit the unusually shaped battery compartments found in many electric vehicles. In this way you can mazimise the battery space available in the most efficient way.
Also we have VMS instead of a BMS.
I will have the new PDF of all the factory packs with photos and specifications next week so if you want to PM me or otherwise advise your email address I will be happy to send you a copy.

 

[RoughRider]

KOKAMS chemistry is: LiNiCoMnO2

this chemistry is knowen as the best compromise(of power, safety and energy density) of all other Li-chemistries...

it is the safest beside LiFePO...

 

[johnrobholmes]

Talked with Kokam yesterday for a while. Right now the 12ah cells are still around $2 per watt hour wholesale for large volumes. They are opening up more factories in an effort to reduce this and become more competitive. Somewhere around .80 per watt hour would be great, but I doubt we will even see $1.2 per w/h wholesale costs for anything below 10k quantities.

 

[RoughRider]

who do you talked to?? a reseller in the us or someone directly in korea?

the quote me a price of 120$ for the 40Ah cell; that makes: 120$ / (40Ah+3,7V) = 0,8$ per Wh... and that was just 300cells...

maybe you mean 2$ per Ah? that would be a good deal...

2$ per Wh is just insane...

 

[johnrobholmes]

I talked with one of the reps at Kokam USA. It was for the 12ah cells. Maybe the 40ah cells don't cost much more to manufacture, and are low discharge rate.

 

[liveforphysics]

I just worked some numbers.

The following are about identical sizes: (40Ah Kokam pack is actually a bit smaller)

A 44.4v 40Ah Kokam pack ($0.80/wh)
A 38.4v 20Ah BMI pack ($1.20/wh)


LiMnCo is a safe battery chemistry. It was shown to be safer than the LiFePO4 cells used by A123 in the battery tests done by GM for choosing a chemistry to use in the volt. We have thousands of LiMnCo cells being used and abused by members of this forum everyday, and has there been a single incident with Kinions? Just like LiFePO4, it's endothermic energy is higher than it's exothermic energy, making it a chemistry that is impossible to sustain thermal runaway.

 

[pwbset]

has there been a single incident with Kinions?

Having completely shorted out like 4 konion VTs in the last 24hrs trying to solder up a test pack I can definitely say that it's not very dramatic. They get very, very hot, but there is no outgassing or explosions etc. I just put them on the cement and let them do their thing until they die, which only takes a couple minutes tops. The positive end of these things is pathetic with just a little black ring tab to protect against the negative can... it's so easy to short these things it's ridiculous... 'course my skillz are pretty terrible. Wish I could solder better. :?

 

[RoughRider]

we need to get a bulk order of kokam cells...

when we can get a price down the 2$/Ah mark...i will buy them...

i need 20x40Ah...that are 800Ahs

when we place a order for 20.000Ahs or higher, than they will answer or email...

 

[Lapwing]

we need to get a bulk order of kokam cells...

when we can get a price down the 2$/Ah mark...i will buy them...

i need 20x40Ah...that are 800Ahs

when we place a order for 20.000Ahs or higher, than they will answer or email...

I'm keen, in the 40AH or 70Ah size. say around 42 cells, I want to say 63 but........ Where do you buy these?

http://www.kokam.com/product/product_pdf/high_power/PL-202_SLPB100216216H_40Ah_Grade.pdf
http://www.kokam.com/product/product_pdf/high_energy_density/El-401_SLPB53460330_70Ah_Grade.pdf
http://www.kokam.com/product/product_pdf/high_power/PL-301_SLPB60460330H_70Ah_Grade.pdf

 

[liveforphysics]

Lapwing- I'm going to see about contacting Kokam via Microsoft's engineering department, and see if they find that an important enough email to be worth responding.

Then, if I can get ~$80/70ah cell, then I will see about making a 1 time group-buy setup or something. I just buy all the cells up-front, and have them sent to somebody responsible in the group buy who is into mailing out packages and stuff, and they can distribute things for everyone in the group-buy. I would go with the 40Ah cells, but I all ready have a 40Ah LiPo setup, and 70Ah just seems like a lot nicer capacity for a high power E-bike. Each cell is only 5.7mm thick, so it really doesn't matter much how many you want to stack, it's still going to be a very compact battery.

Non-volatile LiMnCo polymer 70Ah cells with 700amp burst, 350amp constant rating, and way smaller and lighter than any LiFePO4 offerings. It was good enough to win the TTXGP, and still have a 3.5v resting voltage per cell.


Anybody else out there interested in getting in on a group buy like that? I imagine I will need to at least buy a few hundred cells before they would take an order seriously. 10-20 of them would sure make a wicked E-bike pack

 

[RoughRider]

i dont think you will be close to the 80$/70Ah...if you are lucky, than you will get a price at 2$/Ah...so 140$/70Ah-cell

i hope, you will get a reply...

 

[liveforphysics]

You can all ready buy them at full retail for $120 per 70Ah cell from Metric Mind EV, and that's the price if you are just buying a single cell from them.

I'm pretty sure a manufacture direct deal, with no mark-up from a middle man, and higher quanity pricing should knock things down from the $120/cell price.


I found some pricing from 5 years ago. They cells had worse Ri, and didn't had only a 600cycle life. And guess the price of a 70Ah cell? $394 each in a quanity of 100.

It seems they are having the prices fall, and the cell Ri and life cycles follow the trend of modern LiPo cells in the RC world. RC LiPo packs that used to cost $300 3 years ago now cost $50, and they are way way better quality cells!

Polymer based cells seem to be a technology that just keeps evolving and improving in big ways, while cell costs keep dropping. I love it when that happens

 

[liveforphysics]

Just for an idea of the energy in each indivdual cell, it works out that each 70Ah cell packs exactly the same WH's as 35 x A123 M1 cells.

Yes, not a typo, it takes 35 x A123 M1 cells to equal the energy in a single Kokam 70Ah cell.

This means Team Agni's TTXGP race bike with a 63cell kokam pack was packing the energy of 2,205 A123 M1 cells.

If you make a little stack of 13 of these cells to make a 48v E-bike battery, you have a 3.367kwhr pack.

That would be a tiny little 0.34 cubic foot battery pack, and yet it would run a 750w hubmotor for 4.5hrs of constant full throttle on a single charge... Imagine never letting off the throttle for 4.5hrs continous...

That sort of battery could really change the range possibilities of an E-bike.

I'm guessing the cells for a 48v pack like that made from 13 cells could cost around 1,000-1,200 bucks.

Anyone interested?

 

[RoughRider]

i asked victor at metric mind what the price is...but he didnt answer...

i thought he is uesing the 40AH cells...

look closer on his side...that are 40Ah cells and the price of 120$ for 40Ah is what i know...

SLPB 100216216H...that a 40Ah cell not 70Ah

BUT if you can get a price under 2$/Ah...than i might be in...

 

[RoughRider]

look at ebay...

a 30C RC 22,2V and 5Ah pack from kokam costs 230$ not 50$

 

[regmeister]

deleted

 

[olaf-lampe]

My company is working for over 3 years now with Kokam and they still are the best choice in Power density.

My favorite thing with Kokam is, that they build tailormade cells for your application. ( I believe the height is limited to 10" ) MOQ 200pcs. Deliverytime 6 weeks.
Ask any other manufacturer for this!

-Olaf
Evisol{dot} com
PS: Before you ask: We are not a reseller and we don't have them in stock. (yet)

 

[swbluto]

So I'm lazy. But just in case someone already has the answer handy...

What's the C rating, the gravimetric/specific energy density and the volumetric energy density? What kind of cycle lifespans are typical? What kind of calendar life is typical? What kind of form factor is available (Cylindrical or prismatic)?

If you specify the calendar life, please define the storage conditions. Temperature and SOC would be the big ones.

 

[johnrobholmes]

Kokam has C ratings, shapes, and capacities of all sizes. LOTS of different cells. All prismatic last I checked.

 

[thomas]

anyone know the calenderlife of kokam cells? cycle life looks acceptable 1500cycles at 80% dod and only a few % lost capaticy?

 

[swbluto]

Note, that's the cycle life data based at 1C discharge. A123 had 85% DOD at 1C with 7000 cycles. As far as typical EV use goes, we might expect 1500-2000 cycles. So, do the math, 1500 cycles / 3 = somewhere around 500 cycles in EV use. Unless you can get close to 1C use which I doubt many are aiming for.