New High Rate LiMn cell from Panasonic

[reagle]

Noticed this press release today:
"Using a nickel manganese-based cathode material, Panasonic’s CGR26650A lithium-ion cell exhibits a discharge rate capability of up to 40 A. The component exhibits a typical capacity of 2,650 mAH with a recharge rate to have most capacity recovered within 20 minutes. The cell is suitable for multi-cell applications including portable power tools, medical equipment, memory storage, back-up power and uninterruptible power supplies."
Datasheet is all I was able to find though http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_LiIon_CGR26650A.pdf

 

[paultrafalgar]

Doctorbass!! Are you there, Doctorbass? What do you think to these cells?

 

[pwbset]

Interesting. To compare with the 18650 konion pairs I've been playing with recently... 3.7v @ 3ah (~1.5 wh more), 88g (titch lighter), 10-15C (30-45a) rated discharge. Announced 4 years ago by Sony... guess I'm trying to find out what's so special about these "new" Pana-26650s. I'd probably take them over konion for less cells, bigger format, less chance of build error etc. etc., but performance seems pretty much the same. Wonder if they wouldn't need as much balancing like the konions - that's an enormous plus in my opinion for the average noob pack builder.

I'd be curious to hear if the likes of mcstar or jonrobholmes etc. could get them wholesale/OEM and how much they would cost.

 

[Doctorbass]

Doctorbass!! Are you there, Doctorbass? What do you think to these cells?

Pwbset already mentioned the major differences :wink:

The discharge characteristics are very simialar to the konions.. buttheir anounced voltage is 3.6V and the konion is mostly 3.7 and 3.75V..

I just remind you all that this famous nominal voltage is determined by discharging a cells at 1C and obtained when the voltage reach exactly half the total capacity during discharge.. so the konion would have more Wh because of their nominal voltage higher of 150mV and also because their energy density is a bit higher... 88g for 2650Ah and 86g for a pair of konion that give 3 to 3.2Ah.. some website specify 1.5 Ah per cell some specify 1.6.... by my side, from used cells of around 100 cycles, i get 1.5Ah from them at 1C discharge.

But... I did'nt found any spec about their cycle life.. konion is between 500 and 800 at C/2 What is Panasonic LiMn ?

Doc

 

[dimitrib90]

Doctorbass!! Are you there, Doctorbass? What do you think to these cells?

Pwbset already mentioned the major differences :wink:

The discharge characteristics are very simialar to the konions.. buttheir anounced voltage is 3.6V and the konion is mostly 3.7 and 3.75V..

I just remind you all that this famous nominal voltage is determined by discharging a cells at 1C and obtained when the voltage reach exactly half the total capacity during discharge.. so the konion would have more Wh because of their nominal voltage higher of 150mV and also because their energy density is a bit higher... 88g for 2650Ah and 86g for a pair of konion that give 3 to 3.2Ah.. some website specify 1.5 Ah per cell some specify 1.6.... by my side, from used cells of around 100 cycles, i get 1.5Ah from them at 1C discharge.

But... I did'nt found any spec about their cycle life.. konion is between 500 and 800 at C/2 What is Panasonic LiMn ?

Doc

Did you notice how well the cells work in the heat. At 113 degrees Fahrenheit, it seems to have more ah per v.

 

[Doctorbass]

Doctorbass!! Are you there, Doctorbass? What do you think to these cells?

Pwbset already mentioned the major differences :wink:

The discharge characteristics are very simialar to the konions.. buttheir anounced voltage is 3.6V and the konion is mostly 3.7 and 3.75V..

I just remind you all that this famous nominal voltage is determined by discharging a cells at 1C and obtained when the voltage reach exactly half the total capacity during discharge.. so the konion would have more Wh because of their nominal voltage higher of 150mV and also because their energy density is a bit higher... 88g for 2650Ah and 86g for a pair of konion that give 3 to 3.2Ah.. some website specify 1.5 Ah per cell some specify 1.6.... by my side, from used cells of around 100 cycles, i get 1.5Ah from them at 1C discharge.

But... I did'nt found any spec about their cycle life.. konion is between 500 and 800 at C/2 What is Panasonic LiMn ?

Doc

Did you notice how well the cells work in the heat. At 113 degrees Fahrenheit, it seems to have more ah per v.

with heat you wil lget more Ah but their cycle life will ve negatively affected..

Doc

 

[dimitrib90]

Oh I always though it was the other way around. Good to know. Thanks

 

[oofnik]

So, any sources for these Panasonic cells?

 

[pwbset]

So, any sources for these Panasonic cells?

Seriously... why is it so bloody hard to find raw LiMn cells when raw LiFe cells are a frickin dime a dozen.

 

[reagle]

Could it be the same safety reasoning behind regular Li-Ion cells not being sold to public? My understanding is LiMn is still not as safe as LiFePO4

 

[oofnik]

All of the vendors that carry Emoli LiMn cells that I've contacted have said they are specifically not allowed to sell individual cells. They must build packs with built in safety circuits.

 

[TylerDurden]

Could it be the same safety reasoning behind regular Li-Ion cells not being sold to public? My understanding is LiMn is still not as safe as LiFePO4

LiMn is as safe as LiFe.

LiFe and LiMn formulas emerged at around the same time. The buzz about higher energy density of LiFe (A123) may be why the pouch-style suppliers largely ignored LiMn.

Molicel, Sony and now Panasonic have production lines supplying the powertool industry. AFIK, only A123 is producing LiFe cylindricals on that scale.

 

[dimitrib90]

So, any sources for these Panasonic cells?

Why is everyone so interested in these cells? They have a horrible cycle life of 500 cycles which is the same as a Lead Acid Battery. And of top of that, they are really expensive. The only way I would get them is if I got them individually for mucho cheap, otherwise LiFePO4 is the way to go.

 

[tomv]

The situation with lithium batt sucks. But while we keep waiting you might enjoy reading what I found out about this. Skip the rest of the post if you look for any useful info, it's just for amusement.

LiMn is as safe as LiFe. They won't explode or catch fire if impaled by nail, heated etc. But its still liability is the reason why no reputable manufacturer will sell loose cells. You can find old news releases that E-Moli, a Canadian company and the only lithium manufacturer in North America went bankrupt because of liability lawsuits they got into because of their LiCo batteries.

You can buy chinese crappy cells of any variety, LiCo, LiMn, LiFe, etc. LiFe is just most fashionable. Their datasheets say they are as good as Sonys, E-moly's, but they are not. Lookup reports for Thunderskys for example. They make those cells for years, and they are still horrible, inconsistent quality, not useful for any production applications. Their cycle life is like 5 cycles on some cells, some dead right away, some a few more maybe. Some are better then others of course, but sofar the only Chinese lithium battery maker that is used in volume consumer product is the Yardworks battery. Ever wonder why most tools are still sold with NiCd (poisonous, short life, low-capacity, heavy, as expensive per Wh as Lithium)? Tool makers try much harder then we do to dig up a decent battery. The truth is - there are none.

I've tried to contact battery makers for some time thinking to somehow get the cells. A123 can be reached easy, but were rude and unpleasant to deal with. They just said - buy our evaluation kits. Lots of chinese companies will respond and promise you anything you like to hear. Never dared to give them my CC info. Serious chinease companies like CBAK (manufacturers for A123), BYD won't respond. Nicest guys are at E-Moli, realy sympathetic and helpful. What they told me is - 1) they won't sell to small pack makers due to liability. 2) all their capacity is sold for many years into the future to large tool pack makers

 

[tomv]

Forgot one vendor. Valence batteries are used in mass market product (Segway), and they do sell their battery packs in useful capacities, with BMS and robustly packaged. But they are VERY expensive.

 

[dimitrib90]

I think that our best bet is to go with 38120S cells from headway. So far these cells have outperformed all their other headway cells and they are very cost effective. The only problem is the BMS. I think fechter and goodrum's BMS would work perfect with these cells but we will have to see.