The Future of Rechargeable Lithiums

[Centropolis]

Relatively the advances of the rechargeable lithiums in various formats (14500s, 18650s etc.) have been slow compared to the LEDs and LED flashlights. Many expensive flashlights nowadays are made to be used with one specific battery format only. I thought about it this morning and was a bit concerned for flashlights such as the new Jetbeam Jet-II Pro which uses a 18650….that if no mainstream battery makers like Energizer or Sanyo start making rechargeable lithiums, they'll kind of fade away after a few years.

If I was to spend $80 on a flashlight, I do not want to not be able to find batteries for them unless I go some specialty websites. Are we so sure about these relatively unknown battery formats are going to be continued to be produced in the near future?


Are we going to see rechargeable lithiums with capacities closer to their alkaline counterparts soon?

 

[AvPD]

Don't forget to measure the capacity by milliwatt-hours, a 2000mAh Li-ion battery has about three times the capacity of a 2000mAh NiMH.

 

[IMSabbel]

especially true now that different lithium chemistries also have different voltages:
a 450mAh LiFePo is A LOT worse than a 650mAh LiIon....

 

[LuxLuthor]

Don't forget to measure the capacity by milliwatt-hours, a 2000mAh Li-ion battery has about three times the capacity of a 2000mAh NiMH.

Just to clarify if anyone got confused, technically the "capacity" of a battery is defined in terms of mAh, so 2000mAh Li-Ion is the same capacity as 2000mAh NiMH. The higher voltage of Lithium Ions vs. NiMH is somewhat reduced by lower mAh capacity of Lithium in a given form factor. You don't see any 2000mAh Lithium Ions unless you go up to the 26700mm (larger than C battery) size.

The only way to bring up the capacity of Lithium Ion is putting cells in parallel, which is not very practical in narrow flashlights.

For example:

• NiMH AA 1.2V can have capacity up to 2700mAh

• Lithium Cobalt AA ("14500") @ 3.7V has capacity of only 750mAh

When you go to "safe chemistries" of Lithium Iron Phosphate or Lithium Manganese, the capacity of those same form factor size cells drops even more. For example in larger 18650 size:

• Lithium Cobalt 18650 @ 3.7V has capacity of 2200mAh

• *Safe Chemistry "Emoli" brand - Lithium Manganese 18650 @ 3.7V drops to 1500mAh capacity.

• *Safe Chemistry "Saphion/A123" brands Lithium (Nano) Iron Phosphate 18650 @ lower 3.3V drops further to 1100mAh

 

[2xTrinity]

LuxLuthor -- you're technically right, but what most people actually mean when they refer to or ask about capacity is actually energy-density.

Relatively the advances of the rechargeable lithiums in various formats (14500s, 18650s etc.) have been slow compared to the LEDs and LED flashlights.

It's not like Lithiums have been improving less than other competing formats -- basically all battery technology has improved relative slowly. LEDs on the other hand have been improving at an absurdly fast rate compared to just about any technology.

Many expensive flashlights nowadays are made to be used with one specific battery format only. I thought about it this morning and was a bit concerned for flashlights such as the new Jetbeam Jet-II Pro which uses a 18650….that if no mainstream battery makers like Energizer or Sanyo start making rechargeable lithiums, they'll kind of fade away after a few years.

18650s aren't going away anytime soon. Nearly every laptop battery pack on the market is based on them.

If I was to spend $80 on a flashlight, I do not want to not be able to find batteries for them unless I go some specialty websites.

Your LED is likely to go obsolete before your rechargeble batteries wear out, even if you cycle them full to flat every day. Also, most lights that are able to operate on a 18650 have some sort of voltage regulation, which means they should also work just fine on 2xCR123s, which you can buy in bulk online and stock up on if your concern is having charged batteries around during a blackout.

Are we so sure about these relatively unknown battery formats are going to be continued to be produced in the near future?

Just because a battery format is not commonly sold in stores doesn't mean they won't be made -- 18650s are one of the most manufactured form factors on earth for making battery packs, and online vendors will continue to sell them for years to come, for people who like to repair their old laptop batteries for 1/3rd the price of buying a replacement.

When you go to "safe chemistries" of Lithium Iron Phosphate or Lithium Manganese, the capacity of those same form factor size cells drops even more. For example in larger 18650 size:

The biggest advatnage of those chemistries compared to traditional lithium ion is that they have extrmely high power density -- which is important for things like hybrid vehicles or power tools, but not flashlights and computers, where energy density is more important.

I'm not even sure if those chemistries are inherenetly worse at energy density, or that the manufacturers of those particular cells traded off energy density for the sake of having improved power density.

 

[Fallingwater]

If I was to spend $80 on a flashlight, I do not want to not be able to find batteries for them unless I go some specialty websites. Are we so sure about these relatively unknown battery formats are going to be continued to be produced in the near future?

18650s have been around for ages and they're unlikely to disappear in the foreseable future. Most laptops use them for power, so unless someone comes up with a common standard for square cells you can count on them being around for a long, long time.

 

[bob_ninja]

He likely meant that you don't find individual 18650 cells on store shelves. Many more of them seem to be sold in packs as opposed to individual cells. Which brings up an interesting question. Why not start selling 18650 as individual cells to replace older Cs and Ds, especially NiCds? There were other discussions about "fake" Cs and Ds (AAs with spacers). I would much rather prefer to use 18650s Li cells for toys and other higher drain apps as opposed to right now using AA with C/D spacers.

In other words, why are so many people (like RC crowd) forced to take apart power tools packs? Would be much nicer if you can purchanse individual cells.

As for advances, actually there are a lot of advances in Lithium space. However, most effort is made into other areas, like safety and robust designs as opposed to a higher energy content.

As LL pointed out above, one of the new designs (A123) actually has less energy density. However its other characteristics are much better.

 

[2xTrinity]

He likely meant that you don't find individual 18650 cells on store shelves. Many more of them seem to be sold in packs as opposed to individual cells. Which brings up an interesting question. Why not start selling 18650 as individual cells to replace older Cs and Ds, especially NiCds? There were other discussions about "fake" Cs and Ds (AAs with spacers). I would much rather prefer to use 18650s Li cells for toys and other higher drain apps as opposed to right now using AA with C/D spacers.

A couple problems using LiIon as C/D cell substitutes:

1) Voltage on the LiIon is 3x higher.
2) People would be tempted to throw them onto a NiMH/NiCd charger if they're inside a case the same shape as a C/D cell.

If you wanted to homebrew a parallel pack of LiIons to replace a 3-series pack of NiCads that would work, but don't ever expect anything like that in stores.

Before selling LiIons, I'd rather see more stores start selling low self discharge NiMH cells, even in C/D sizes. Any device that would work on a NiCd or Alkaline C or D will work with a REAL C or D NiMH.

 

[bdsmchs]

Don't worry guys. Eventually, batteries even in flashlights will all be replaced by tiny ethanol-powered fuel cells

Battery technology is essentially stagnant compared to other forms of technology (like the example used in this thread, LED advances). What truly gets me excited is seeing where super-capacitors are going.

Super-capacitors are kinda following a similar advancement curve as LED's. Remember when the only thing LED's were good for were small red/green/yellow indicator lights for consumer electronics? Then all of a sudden blue LED's and other high-powered small LED's started coming out that were actually useful in lighting applications. Shortly after, the white LED was developed, and soon they will be at a point to replace compact fluourescents as home lighting. Well, it's the same with super capacitors. While battery technology has grown by very small percentages every year, capacitors jumped a hurdle and the advancement is just exploding with leaps and bounds.

There is a lot of serious development going into super-capacitors for electric car use since an electric car won't ever replace gasoline as long as it takes 8 hours to "fill up". With super-capacitors that will no longer be the case.

I truly believe that batteries will be replaced by capacitors in a short timeline. There is no reason that you couldn't make a 3.7v super-capacitor in an 18650 form-factor, with twice or more capacity.

This WILL happen. And I can't wait!

 

[Fallingwater]

I truly believe that batteries will be replaced by capacitors in a short timeline. There is no reason that you couldn't make a 3.7v super-capacitor in an 18650 form-factor, with twice or more capacity.

*sigh* yes, there is. Even if capacitors were to eventually get to the energy density of today's batteries (and I have my doubts), they have, by their nature, a very steep discharge curve. This is a big problem.

They *might* have some success as battery replacements in the niche market of flashlights and other gadgets that eat little power and/or don't need long runtimes, but they aren't going to replace mainstream batteries anytime soon.

For the nth time: capacitors are very good energy buffers, but they are lousy energy sources.

There have been many threads about this in the past. Search for them and you'll find far more complete explanations.

 

[Bones]

They *might* have some success as battery replacements in the niche market of flashlights and other gadgets that eat little power and/or don't need long runtimes, but they aren't going to replace mainstream batteries anytime soon.

If they do find a way, it will certainly be convenient though.

According to Popular Mechanics, this little screwdriver will run almost 2/3 as long as its battery powered counterpart, which would normally be considered 2/3 as useful, except that it will fully charge again in a mere 90 seconds:

http://gizmodo.com ... coleman-flashcell-cordless ...

 

[2xTrinity]

If they do find a way, it will certainly be convenient though.

According to Popular Mechanics, this little screwdriver will run almost 2/3 as long as its battery powered counterpart, which would normally be considered 2/3 as useful, except that it will fully charge again in a mere 90 seconds:

http://gizmodo.com ... coleman-flashcell-cordless ...

Believe it or not, there are batteries on the market now in power tools that theroetically recharge in 90 seconds, but with 20 times more energy density than Ultracaps.

A123 cells, rated for 60C discharge (full to flat in one minute) and IIRC something like 30C charge (recharge in 2 minutes).
Capacitors have ZERO advantages over LiFePO4 cells for power tools and two key disadvantages:

10-20x lower energy density
gradually decreasing voltage curve

And in fact the whole "flash recharge in 90 seconds" thing pretty much fails to work in any application that stores enough energy to actually be useful because the currents necessary to recharge that fast are insane.

Consider a single 26650 A123 battery. They store 2.3 Amp-hours. To recharge that in two minutes you'd need to feed it 60 amps. Any power supply capable of handling that will not be cheap, and certainly won't work with the wimpy contacts used in that Coleman dock charger. That fact alone tells me that the Coleman won't actually store very much energy, simply becuaes it charges in 90 seconds, and no way are they running 10s of amps.

Now consider recharging an electric vehicle in five minutes. In order to have useful range in a pure electric vehicle, about 100kWh would be necessary. Recharging that in less than 5 minute will require well over a megawatt of power. That means either voltages so high they they're EXTRMELEY dangerous (ie, far more dangerous to handle than self-serve gasoline), or currents so high you'd need copper conductors the size of large hoses.

IMHO plug in hybrids that have the option of filling up on gasoline for long trips, or trickle-charging overnight using cheap off-hours electricity. Thousands of vehicles sucking a megawatt of power each in the middle of the daytime when the electric grid is already overburdened is not a good thing.

The electric component could cover just enough range for daily commuting (maybe 90% of all driving) and gasoline would be a backup for long trips (maybe 10%) The best thing about that approach is that enough power to recharge overnight is available straight out of a normal 240V washer/dryer outlet present in most garages. And the power supplies are built into the cars themselves. No new infrastructure is necessary.

 

[bob_ninja]

A couple problems using LiIon as C/D cell substitutes:

1) Voltage on the LiIon is 3x higher.
2) People would be tempted to throw them onto a NiMH/NiCd charger if they're inside a case the same shape as a C/D cell.

If you wanted to homebrew a parallel pack of LiIons to replace a 3-series pack of NiCads that would work, but don't ever expect anything like that in stores.

Before selling LiIons, I'd rather see more stores start selling low self discharge NiMH cells, even in C/D sizes. Any device that would work on a NiCd or Alkaline C or D will work with a REAL C or D NiMH.

Actually what I would like to see is a transition by electornics makers away from C/D to Lithium formats like 18650s for instance. So battery compartment would actually accept 18650 instead of 2 or 3 Ds for instance. I am tried of homebrew and improvisation, adapters, etc. It would be much easer to simply sell individual 18650s say by A123 that can be used directly in a say remote control car for kids, and such.

 

[2xTrinity]

Actually what I would like to see is a transition by electornics makers away from C/D to Lithium formats like 18650s for instance. So battery compartment would actually accept 18650 instead of 2 or 3 Ds for instance. I am tried of homebrew and improvisation, adapters, etc. It would be much easer to simply sell individual 18650s say by A123 that can be used directly in a say remote control car for kids, and such.

Intersting. With safe chemistries like LiFeP04 this is feasible. I think that in the past they would have been apprehensive about selling old Li-Cobalt over the counter, even with protection, because of potential safety issues in the event the cells are abused. LiPos are particualrly dangerous to handle indivudally because of their soft cases, and tendency to burst into flames if you look at them the wrong way...

I honestly don't expect a shift away from standard AA/AAA anytime soon, too many devices alraedy use them and people aer in the habit of buying alkalines for all of their devices. It's true though that with C/D cells there are much fewer devices using those, most companies are going to proprietary packs. I don't expect that to change because they can make a lot of money from a high markup there. I also don't see companies like Energizer pushing for a shift away from disposable anytime soon, especially now that for high power devices they are selling bucketloads of disposable lithium AAs for $2.50/each...

I'd like to see soem third parties offer "adapters" that fit into companies' proprietary cell holders, but allow user swappability of the cells. for example, I have some canon camera packs which are obviously just two 14500s bundled togther -- a 3rd party "carriage" that actually allow the user to swap THOSE CELLS, but still mate with the contacts in the camera, might be a nice compromise.

 

[Fallingwater]

Intersting. With safe chemistries like LiFeP04 this is feasible

Feasible yes, but (as you say yourself) companies have far better profit margins in going proprietary than in letting people replace cells with common-or-garden LiFes.
Maybe we'll have some companies that don't want to bother with the whole battery thing and will just use standard ones, but I don't see the mainstream market going in this direction, sadly.

I wonder if there's money to be made in aftermarket external cells...

For example, I see lots of video cameras that use tiny wimpy LiPo packs and last an hour or so. Would people be willing to pay for something like an external 18650, or 2p pack of 14500s?
All it takes to do this is to gut the original pack, remove the tiny cell and solder two leads. The problem would be in fitting the external pack it in a way that wouldn't make people go "oh, that's ugly, I don't want that", like they always do when they see my own battery hacks. Apparently aesthetics are more important than having 4x the runtime. *sigh*

I'd like to see soem third parties offer "adapters" that fit into companies' proprietary cell holders, but allow user swappability of the cells. for example, I have some canon camera packs which are obviously just two 14500s bundled togther -- a 3rd party "carriage" that actually allow the user to swap THOSE CELLS, but still mate with the contacts in the camera, might be a nice compromise.

14500s are the same size as AAs. You could maybe hack together what you want from a standard 2xAA battery carrier modified for parallel connection (IIRC canon packs are 3.7V).

Or just gut the original pack and rewire it with battery contacts, so you can open it up and replace the cells if need be.

 

[Frankiarmz]

A couple problems using LiIon as C/D cell substitutes:

1) Voltage on the LiIon is 3x higher.
2) People would be tempted to throw them onto a NiMH/NiCd charger if they're inside a case the same shape as a C/D cell.

If you wanted to homebrew a parallel pack of LiIons to replace a 3-series pack of NiCads that would work, but don't ever expect anything like that in stores.

Before selling LiIons, I'd rather see more stores start selling low self discharge NiMH cells, even in C/D sizes. Any device that would work on a NiCd or Alkaline C or D will work with a REAL C or D NiMH.

After reading your post I was curious how much voltage my Tenergy NIMH D cell lost while sitting in my drawer. I haven't charged them in over six weeks that I can recall. Unlike my AA or AAA NIMH which lose quite a bit in a couple of weeks, the D cells read 1.280 volts! I was pleasantly surprised they held up so well, is this typical?

 

[Fallingwater]

Measuring resting voltage is not a good way of gauging the charge level of a NiMH cell. Apply a load (say, half C) and measure again.

 

[David Gretzmier]

Nearly a year ago there was an article published about putting more manganese in Lithium rechargables in a lab and they doubled the mah of the cells. I wander if this technology is eventually gonna make it's way to the consumer or not?

2 questions for a newbie to battery technology-

also, forgive my stupidity, but on the nimh vs. Lithium rechargable battle- shouldn't a single lithium "d" cell at 7500 mah, 3.7 volts have roughly the same run time on flashlights as 3 nimh "d" cells rated at 7500mah each? ( 3 x 1.2 volts = 3.6 volts? ) yes, they have higher mah available in nimh, but I'm asking if the mah is the same, and the voltage is same...

2nd stupid question- why is it that primary lithium has so much more mah than rechargable? there are several D size primary cells floating around the internet at 17,500 mah, even 19500 mah. Is the chemistry so different they lose half or more of the energy density?

 

[SemiMan]

Don't worry guys. Eventually, batteries even in flashlights will all be replaced by tiny ethanol-powered fuel cells

Battery technology is essentially stagnant compared to other forms of technology (like the example used in this thread, LED advances). What truly gets me excited is seeing where super-capacitors are going.

Super-capacitors are kinda following a similar advancement curve as LED's. Remember when the only thing LED's were good for were small red/green/yellow indicator lights for consumer electronics? Then all of a sudden blue LED's and other high-powered small LED's started coming out that were actually useful in lighting applications. Shortly after, the white LED was developed, and soon they will be at a point to replace compact fluourescents as home lighting. Well, it's the same with super capacitors. While battery technology has grown by very small percentages every year, capacitors jumped a hurdle and the advancement is just exploding with leaps and bounds.

There is a lot of serious development going into super-capacitors for electric car use since an electric car won't ever replace gasoline as long as it takes 8 hours to "fill up". With super-capacitors that will no longer be the case.

I truly believe that batteries will be replaced by capacitors in a short timeline. There is no reason that you couldn't make a 3.7v super-capacitor in an 18650 form-factor, with twice or more capacity.

This WILL happen. And I can't wait!

I think the progress of super capacitors is debateable. The basic technology has been around for some time and only since they have become commercially interesting have they gotten that much better. They are a large way from ever powering a car or even flashlight though and there are significant hurdles to overcome. LEDS have been around 30 years remember. Supercaps could run into unforeseen hurdles or at least we may find that it becomes too expensive.

In terms of stagnant battery technology, we are very close to that not being true. There are starting to show up lab results using nano-particle technology that promises 2-3x improvements in both NiMH as well as Lithium chemistries. That would significantly change the economics of these technologies.

Semiman

 

[2xTrinity]

Nearly a year ago there was an article published about putting more manganese in Lithium rechargables in a lab and they doubled the mah of the cells. I wander if this technology is eventually gonna make it's way to the consumer or not?

2 questions for a newbie to battery technology-

also, forgive my stupidity, but on the nimh vs. Lithium rechargable battle- shouldn't a single lithium "d" cell at 7500 mah, 3.7 volts have roughly the same run time on flashlights as 3 nimh "d" cells rated at 7500mah each? ( 3 x 1.2 volts = 3.6 volts? ) yes, they have higher mah available in nimh, but I'm asking if the mah is the same, and the voltage is same...

Yes, they have the same watt hour capacity, which generally translates into the same runtime (Watt-hours = Ah * Voltage). Note thiere is an exception where this is not true, and that is in a high drain application where one type of chemistry has a high internal resistance, which causes the effective voltage under load to sag and deliver less total energy to the load.

Both NiMH and LiIon should have very low internal resistance. Alkaline battereis on the other hand tend to do worse than NiMH for high drain applications, even though under low drain they might last slightly longer.

2nd stupid question- why is it that primary lithium has so much more mah than rechargable? there are several D size primary cells floating around the internet at 17,500 mah, even 19500 mah. Is the chemistry so different they lose half or more of the energy density?

The batteries your'e thinking of are an example of a chemistry that's only meant for low-drain applications. Cells meant for super low draw can often have more capacity, but they're essentially useless for devices like flashlights. They're meant for devices like sensors etc. that require trickle charges over 10-20 years.