Highest energy density and highest power cells available

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
Hi Gents,

I've not been getting onto Pedelecs so much recently as I've been a bit busy with some rather special cells I've been working with. These cells are LiFePO4 and are produced by a very famous and regarded by many as the no. 1 cell manufacturer in the world. They certainly perform and not only have the highest energy density of any LiFePO4 cell currently available that I'm aware of, but they also produce amazing levels of current. How about 400A constant out of a 20Ah cell. Even the baby 15Ah cells will deliver 700A for a few second burst whilst maintaining voltage levels above 2.0V. They do not have a problem running an ezee motor :) Now if you were running 15 or 20 ezee motors, you might be pushing them a bit hard, but they could still do it. Nearly forgot, 7000 cycles lifecycle and 10-15 years if the SOC and DOD is controlled to 85% or so.

Here's some size and weight details:

Model: AHP 70165227 Model: AHP 68150211
Capacity: 20Ah Capacity: 15Ah
Size: 7.0X 165X227mm Size: 6.8X 150X211mm
Weight: 480g Weight: 400g

These cells are a prismatic or foil pouch cell. I've been very busy with getting a good termination method for these cells and now have something I'm happy with. Here's a few pics of a 12S, 15Ah (actually they are generally 16Ah plus) pack I assembled today. This has a total weight of 5.2kg including BMS and a mechanical termination method that is a DIY job if you are reasonably competent.

Anyway attached are a few pics of a 12S 15Ah pack 225mm * 150mm * 81mm (actually a bit thinner than above spec :)
 

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Herb

Pedelecer
Nov 9, 2009
106
0
I have seen your work on ES and believe you have tried to find solutions to the problems as you encountered them.

I also believe the UK market is smaller and less mature (adventuress) than the US and could prove difficult to gain interest in new products from an individual.

If I didn’t already have a Ping, two FatPacks and a very small A123 pack I would find them hard to resist.

So many of the Forums posts are about replacement batteries and the pedigree of your cells is one of the best.

I hope somebody takes the plunge because this is an interesting battery.

Before anyone else asks – what are the costs.

Herb
 
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emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
I really think most do not comprehend the difference between a pack of these cells and run of the mill cells. The power they deliver is unbelievable.

A pack like that would be 450USD for the cells (37.50USD a pc), about 80USD for assembly and parts, BMS 45USD, 5A charger 60USD, so 635USD or about 400GBP at todays terrible exchange rates. You'd also need to figure in shipping at maybe around 100USD and paypal commission if that was used.
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
I should add that I will happily supply the parts necessary for self assembly and this would save a bit. With the assembly parts I've developed it really isn't so difficult to assemble a pack yourself and no special tools are required. So if you were willing to get your hands dirty and let them get to UK on the slow boat you could have a 36V 15/16Ah pack with assembly parts (not assembled, no BMS or charger) delivered to the UK for about 360GBP.

I used that pack above on a bike fitted with dual 500W motors and dual 25A controllers so 50A and in excess of 2000W. For most of the pack discharge the voltage under full load remains well over 37V. I'd be very interested if anybody can come up with any cell presently available cell type/pack for any cost that can deliver the power, energy density and cycle life, let alone this low price per Ah. This isn't hot air, look on Endless Sphere, lots of people have already had cells from me and I'm presently putting together a pack for a possible TTXGP bike.
 

zebody

Pedelecer
Oct 19, 2009
57
19
East Yorkshire
I should add that I will happily supply the parts necessary for self assembly and this would save a bit. With the assembly parts I've developed it really isn't so difficult to assemble a pack yourself and no special tools are required. So if you were willing to get your hands dirty and let them get to UK on the slow boat you could have a 36V 15/16Ah pack with assembly parts (not assembled, no BMS or charger) delivered to the UK for about 360GBP.

I used that pack above on a bike fitted with dual 500W motors and dual 25A controllers so 50A and in excess of 2000W. For most of the pack discharge the voltage under full load remains well over 37V. I'd be very interested if anybody can come up with any cell presently available cell type/pack for any cost that can deliver the power, energy density and cycle life, let alone this low price per Ah. This isn't hot air, look on Endless Sphere, lots of people have already had cells from me and I'm presently putting together a pack for a possible TTXGP bike.
Hi My wife and I have ezeetorq,s currently 37v lipoly 10AH batteries.
Building a kit sounds a bit hi tech
I am interested in re celling a battery but would not have a clue how to do it can you please advise.
Zebody
 

fishingpaul

Esteemed Pedelecer
Sep 24, 2007
871
86
Can you supply a 36v 15ah lifep04 battery +bms and charger that would give simillar performance as a ping battery, your batteries look good value for the performance they can deliver, but seem a lot more powerfull than most users on this forum would ever need,do you have anything less powerfull available.
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
Hi My wife and I have ezeetorq,s currently 37v lipoly 10AH batteries.
Building a kit sounds a bit hi tech
I am interested in re celling a battery but would not have a clue how to do it can you please advise.
Zebody
Unfortunately I doubt these cells would fit into a typical ebike battery enclosure. The enclosures tend to be narrower than these cells. The 15Ah cells are approximately 15cm wide.

The main hurdle to changing the cells in your batteries would be that LiPoly is typically smaller and lighter per Wh than LifePO4 so you might have trouble fitting equal capacity of LiFePO4 into that enclosure. It would also be tricky to find the appropriate sized cells that could make the best use of the available space inside the enclosure. Maybe you could find a an alternative complete battery that uses the same mountings and connections?? The enclosure used on the Torq looks very much like those that are commonly available but I don't know that model intimately so I wouldn't know for sure I'm afraid. Sorry I can't be of more help.
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
Can you supply a 36v 15ah lifep04 battery +bms and charger that would give simillar performance as a ping battery, your batteries look good value for the performance they can deliver, but seem a lot more powerfull than most users on this forum would ever need,do you have anything less powerfull available.
Thanks Paul :)

Yeah I know these cells are not for everyone but if you were looking to have a slightly illegal bike... then these fit the bill very nicely. I will try to diversify a bit more in the future and start to supply packs with lower C ratings and price tags :)
 

flecc

Member
Oct 25, 2006
52,763
30,349
No, they won't fit into the eZee case which has a rather awkward step in the internal dimensions. This case was originally designed for six vertical columns of five NiMh "D" cells each column.

The basic internal rectangle of the eZee battery case is 304 mm x 99 mm x 64 mm.

The uppermost 80 mm of the rectangle widens from that 99 mm to 109 mm.
.
 
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highrider

Finding my (electric) wheels
Jan 29, 2008
7
0
PL25
lower capacity - yes please

I agree with Paul. I am looking to have a "lightweight" battery to use on a light weight bike, just to ease my way up the biggest of hills. I would love say an 8Ah battery to put on a folder. I use the train to go on rides and for joined up travel solutions and lugging an extra heavy battery up loads of steps is no joke (Worcester station has extra as the station is at roof level)

The size of enclosure is irrelevant to me as I only have conversion kits so I can make a bag to fit and put it into a pannier or fix to a rack.

How about it Emissions?
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
I do take note and will look at trying to offer some more options. The A123 26650s in a small pack can still give great power if you haven't got far to go. There are also various Li Polymer and LiFePO4 pouch cells that give good performance in a compact package with sufficient current to easily power a Euro legal ebike.

I used a 36V 6Ah pack for most of my commuting until recently. This can still give a genuine 10 miles at a good speed (illegal) with some pedaling, a good bit more if you pedal lots and go slow. Even in fairly standard LiFePO4 cylindrical cells with a proper case that is still only about 2.7kg.

You really can't beat the A123 26650 cells though TBH and if you don't have far to go they are a good option in a 1 or 2 parallel configuration, plus they can deliver very illegal power if requested so absolutely no bother at legal power levels. I can get some of these made into small packs if anyone is interested. It's roughly 7USD per cell (3.3V, 2.3Ah) and I can add a small fairly low cost BMS (about 40USD) so it can be charged from a standard charger. A 36V 4.6Ah pack would work out to about 230USD plus shipping etc. Total weight less than 2kg
 

Mussels

Esteemed Pedelecer
Jun 17, 2008
3,207
8
Crowborough
Unfortunately I doubt these cells would fit into a typical ebike battery enclosure. The enclosures tend to be narrower than these cells. The 15Ah cells are approximately 15cm wide.

The main hurdle to changing the cells in your batteries would be that LiPoly is typically smaller and lighter per Wh than LifePO4 so you might have trouble fitting equal capacity of LiFePO4 into that enclosure. It would also be tricky to find the appropriate sized cells that could make the best use of the available space inside the enclosure. Maybe you could find a an alternative complete battery that uses the same mountings and connections?? The enclosure used on the Torq looks very much like those that are commonly available but I don't know that model intimately so I wouldn't know for sure I'm afraid. Sorry I can't be of more help.
I'm a bit confused, above you said these were the highest density cells available but now it seems that LiPoly is denser, were you referring to just LiFePO4 and how do you measure density (weight, size)?
I'm not trying to pick holes but you don't seem to mention watts or voltage so I'm unable to work out what the capacity is, I thought originally you meant per 1.2V cell but the photo is of a battery.
I could probably work it out if I count the layers in your battery but I'm not in the market for a battery so can't be bothered. :)
 

eddieo

Banned
Jul 7, 2008
5,070
6
"A 36V 4.6Ah pack would work out to about 230USD plus shipping etc. Total weight less than 2kg"

Hmmm...would it be possible to bi wire a wisper with one of these? a bit like they do with the ezee? would it mean more power for hill climbing?:p
 

flecc

Member
Oct 25, 2006
52,763
30,349
I'm a bit confused, above you said these were the highest density cells available but now it seems that LiPoly is denser, were you referring to just LiFePO4 and how do you measure density (weight, size)?
I'm not trying to pick holes but you don't seem to mention watts or voltage so I'm unable to work out what the capacity is, I thought originally you meant per 1.2V cell but the photo is of a battery.
Lithium Iron Phosphate cells (LiFePO4) have a lower working voltage of 3 to 3.3 volts per cell against a nominal 3.7 volts for most other lithium chemistries, and they have a slightly lower density than other types. Their maximum charging voltage is also lower at 3.6 volts per cell.

I think emissions-free meant the density was the highest of all LiFePO4 cells on the market.
.
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
I was only referring to the cells themselves and yes I didn't state LiFePO4 in the but I did in the message.

The 20Ah cells are generally 467g and are 3.3V nominal, 20Ah, so 66Whrs per cell. So they have an energy density of 141.3Whrs/kg combined with very high power density of something like 3000W/kg plus for bursts. They do this while still remaining 1 of the safest chemistry and offering exceptional lifecycle when tested for automobile applications. I'm not so sure that typical li polymer cells offer energy density equal to these figures and they definitely don't do 7000 cycles or 10-15 years.
 
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Mussels

Esteemed Pedelecer
Jun 17, 2008
3,207
8
Crowborough
I was only referring to the cells themselves and yes I didn't state LiFePO4 in the but I did in the message.

The 20Ah cells are generally 467g and are 3.3V nominal, 20Ah, so 66Whrs per cell. So they have an energy density of 141.3Whrs/kg combined with very high power density of something like 3000W/kg plus for bursts. They do this while still remaining 1 of the safest chemistry and offering exceptional lifecycle when tested for automobile applications. I'm not so sure that typical li polymer cells offer energy density equal to these figures and they definitely don't do 7000 cycles or 10-15 years.
Thanks, that is much clearer to me.
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
They don't do the life cycle for sure but the Zippy RC packs are good in terms of power density. As an example to build a 36v pack (37v nominal with Lipo) to compare against your cells at 36v using a 12s1p config, your cells have a 792wh ( yum :) ) that weighs in at 5.6Kg.

The Zippys can't compete on the cell / wh density but used in a 10s2p config using the 5ah packs (actually they are better than this and come in over 6ah....) you can build a 370wh pack that weighs just 2.48kg for a wh / kg density of 149.2 ;) These are 20c/30c rated cells too so for a Euro E-bike application its possible to build a 143x51x160mm pack at 2.5kg or so...not bad.
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
They don't do the life cycle for sure but the Zippy RC packs are good in terms of power density. As an example to build a 36v pack (37v nominal with Lipo) to compare against your cells at 36v using a 12s1p config, your cells have a 792wh ( yum :) ) that weighs in at 5.6Kg.

The Zippys can't compete on the cell / wh density but used in a 10s2p config using the 5ah packs (actually they are better than this and come in over 6ah....) you can build a 370wh pack that weighs just 2.48kg for a wh / kg density of 149.2 ;) These are 20c/30c rated cells too so for a Euro E-bike application its possible to build a 143x51x160mm pack at 2.5kg or so...not bad.

Yeah of course RC lipo is good stuff but if over charged or over discharged it is liable to burst into flames. They sell fire proof bags for charging :eek: You can only get good lifecycles if you are very careful with not going to deep discharge levels. It is not forgiving and the prices are not much cheaper than these cells per Wh so if anything these facts make the prismatics even better value. Oh and by the way the 15Ah cells are not as high energy density as the 20Ah cells so a 15S 20Ah pack, 36.3V nominal would come in better than the above example I gave at 5.14Kg for an 11S 20Ah pack and you could use all the capacity without fear of it dramatically shortening the lifecycle or going up in flames.

I've spoken to companies that manufacture high C rate LiPo that is used for RC and they state it is not safe in big packs. I can't see many auto manufactures going with lipo because they can save what 15% but you need to change the pack every 6 months and it bursts into flames if you let it go into the red ;)

All I'm trying to show is that there are new and better batteries coming without any real ifs or buts and things should only get better. These cells will likely not be in Ebikes but hopefully in lots of EV Cars in the not too distant future. I've already sold lots of these and the most of the remaining cells are likely already spoken for by an existing customer.
 

eddieo

Banned
Jul 7, 2008
5,070
6
"A 36V 4.6Ah pack would work out to about 230USD plus shipping etc. Total weight less than 2kg"

Hmmm...would it be possible to bi wire a wisper with one of these? a bit like they do with the ezee? would it mean more power for hill climbing?:p
so a 2 kg pack of 4.6 amp in parallel with wisper 14 amp and just switched in for hill climbing...would this be feasible?
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
so a 2 kg pack of 4.6 amp in parallel with wisper 14 amp and just switched in for hill climbing...would this be feasible?
Yeah I do believe it is feasible but I don't really have the time right now to take on another small project like engineering a complete solution. I have a big pack that is already overdue and it has been big headaches and untold time sorting out all the little details.

Also I'm not so sure that it would actually make a big impact on the hill climbing ability. Is the battery sagging that bad under load? I doubt it TBH. At the end of the day 250W rated just doesn't actually do much especially when presented with a hill or a strong headwind. It's quite likely just limited power from the controller and motor combination and no amount of battery will fix that. The standard way to get a bit more power from a motor is a few more volts which would require an additional pack to be switched in series. It's all possible and none of it's rocket science but there's bound to be a few niggles and a bit of time to sort it all out. It might be simpler to just try and get hold of the higher power motor and controller combo that whisper offer, but be very careful venturing into the heady speeds of 15mph plus :eek: :D