Talk:Lithium polymer battery/Archive 1

Article should be deleted/merged
The current content of the article should be mostly deleted/merged with lithium ion. Let me explain:

There are two primary technologies:
 * 1) Lithium ion
 * 2) The Old Lithium Polymer

Originally, lithium polymer was proposed as an alternative for lithium ion technology, so that the liquid electrolyte - porous plastic separator combo would be replaced with a polymeric electrolyte. These kind of cells never went into large-scale mass production; the most prominent problem was that they needed heating elements because the performance at room temperature was poor. THIS technology is the only true "lithium polymer", and the article clearly has pieces that describe this technology. Even this lithium polymer is still a subset of lithium ion - there is no metallic lithium anywhere.

Then, there is current lithium ion, which has stayed relatively similar from the 90's: it uses a mix of lithium salt in an organic solvent with several additives. Many different material choices are possible, and they are all called lithium ion.

In addition to different compositions, there always have been different "form factors", namely, cylindrical, prismatic and pouch.

"Lithium polymer" held great expectations but it never realized. Some companies, mostly Chinese but some Korean too, started applying the name to standard lithium ion cells using the prismatic or pouch form factor, purely for marketing purposes. Surely, there can be minor differences in electrolyte additives and/or composition; a gelling agent is usually added. Even if there wasn't, every li-ion cell uses a plastic (polymer) separator, so yes, there are always polymers present.

From a technical viewpoint, this kind of "polymer" cell is no different from a li-ion cell that does not have a "polymer" designation. In fact, the normal differences between the li-ion cell chemistries can be much larger than the presence of gelling additive.

The cells you are using in your model airplane are just standard lithium ion cells in a pouch format. Of course optimized for high power output at the expense of energy density, but this has nothing to do with "lipo" or not. Power tools use similar cells in a cylindrical format.

I have talked with chief technical personnel from battery manufacturers and their stance is that there is no such a thing as "li-poly", and marketing should tell this to the customer, but if the customer still wants to buy "li-poly", then they can say that yes, our technology is "li-poly". Go figure. Lipo's nothing but a meaningless buzzword.

While I accept that marketing terms are vague and not based on scientific facts, Wikipedia should do better. This page is a prime example of DIY hobbyists writing some hearsay down as facts (and hence, it looks like a forum discussion). "Lithium polymer" is such a widespread myth that even battery manufacturers must play along "accepting" it in order not to lose their business. But let's start the "cleanup" of the concepts from Wikipedia; this article should only discuss the original polymer-electrolyte contraption and make sure that people are guided to the li-ion page, which should mention that pouch cells are sometimes (maybe even incorrectly) called "lithium polymer". — Preceding unsigned comment added by 130.230.89.77 (talk) 23:42, 20 May 2014 (UTC)


 * WP:COMMONNAME We have to communicate with our readers, so that they can find content and understand it. Articles titles aren't defining, they're comprehensible labels. If the common name is a misnomer then we deal with that (with reliable sources) inside the article. Andy Dingley (talk) 03:11, 21 May 2014 (UTC)


 * I agree. Therefore, "lithium polymer" article must refer the reader to the lithium ion article clearly, and explain about the confusion of the terms. Then, this page can talk about the original "lithium polymer", which is practically non-existent. 188.67.170.227 (talk) 16:19, 21 May 2014 (UTC)


 * It would be much better (in terms of wiki-engineering) to keep this article discussing what it is discussing as a subject, and to create a new article under Lithium polymer battery (original meaning) or some variant.
 * We could then expand this article to clarify the distinction, maybe even (after discussion) rename or clarify it. For the sake of preserving clear edit histories etc. though, the bulk of the content of this article needs to stay here as part of this article. Anything else is just a mess for wiki-tech. Andy Dingley (talk) 17:08, 21 May 2014 (UTC)


 * But the BULK of the content is either misinformation (I took a first shot of removing some of it) or duplication from li-ion page. Because it's the same technology, the same things are true (such as how to charge it, how to discharge it, how to maintain it, voltage limits, temperature limits, thermal runaway, electrode materials, other materials, 99% of the manufacturing technology etc.), and it is problematic to maintain two separate articles that discuss the same thing with different names. So, I think the best course of action is removing the duplication and only discuss how these "polymer" cells differ from those that do not bear the name. The answer varies, so it is a valid point to discuss in the article. In any case, "lipo" is only a small subset of li-ion. Then, the page would be short and would refer the reader to the li-ion page for the general information which is common for both. 188.67.170.227 (talk) 20:46, 21 May 2014 (UTC)
 * I agree with your comment. Basically, a LiPo cell is a lithium ion cell in pouch format. This needs to be understood. I think this article needs to be kept as there is a big community that wants to know about LiPos, but we should word the article in such a way that the reader understands that LiPos are exactly lithium ion cells, and should they require more technical information, they should consult that article.137.132.22.191 (talk) 09:17, 19 June 2014 (UTC)

Capacity Rating
The Capacity Rating section as it reads is very poor.


 * First, it ends with and.....
 * "So, a 10Ah battery pack with a nominal voltage of 10 volts would deliver 36,000 Coulombs of charge (or 2.2 x 1023 electrons), and"


 * The voltage is totally irrelevant. 86.180.84.187 (talk) 16:54, 25 March 2011 (UTC)


 * Second, it has a confusing (the way its written) formula to produce undefined unit value.


 * Third, it uses the shorthand calculations for Ah without any context on the error this will produce by not taking into account the discarge rate.


 * Fourth, it depicts that AmpMinutes as easier-to-use that the more common/used AmpHour(Ah) and AmpSecond (Coulomb)

Larek (talk) 14:23, 27 July 2009 (UTC)
 * I came here to say the same thing, it is very confusing as it is currently written. The plain-english formula with undefined units is the main problem I think. If that part were cleaned up to add proper units and perhaps use the standard Wiki math formatting, it would be a lot more clear. Cecilkorik (talk) 03:03, 29 July 2009 (UTC)

So far I have never seen the AmpMinute unit being actually used in a real world calculation, it only confuses the reader. I would recommend removing all references to AmpMinute from the article all together. --ArticCynda (talk) 22:10, 17 March 2010 (UTC)

One big problem with this whole article, and discussion is that there are basically two types of modern lithium polymer cells, those intended to run electronics, and those intended to run RC stuff. There should be two articles, one for each. The RC stuff is extreme, designed for high discharge rate and charged with specialized chargers. It is also much more dangerous than the cells made for driving electronics. The cycle life is low, but the discharge currents are enormous. — Preceding unsigned comment added by 50.73.46.101 (talk) 00:56, 16 February 2013 (UTC)

Design Origins
This type has technologically evolved from lithium-ion batteries (primary batteries). Ultimately, the lithium-salt electrolyte is not dissolved in an organic solvent as in the lithium-ion design, but in a solid polymer composite such as polyethylene oxide or polyacrylonitrile. The advantages of Li-poly over the lithium-ion design include lower cost manufacturing and being more robust to physical damage. Lithium-ion polymer batteries started appearing in consumer electronics around 1996.

The design origin states that the LiPo battery is an evoloution of Lithium-Ion batteries which are primary cells but the table at the bottom of the article and the Lithium-Ion article both say that Lithium-Ion is a secondary cell. The section also has very little to do with the design origins of the cell, it is mostly a small discussion on LiPo vs lithium-Ion chemical composition which probably deserves to be covered in more detail in a different section.

--Spuzzdawg (talk) 23:32, 4 June 2009 (UTC)

I thought I'd add this: Lithium-Ion's are more physically robust than LiPo? Since when? I've never seen a Li-Ion battery catch fire from being dropped. I only have anecdotal evidence but it's quite strong.. can anyone else comment? —Preceding unsigned comment added by 173.75.166.197 (talk) 05:56, 14 June 2009 (UTC)

--Sammy

Totally agree with Sammy. Lithium Ion batteries are definitely not inherently more physically robust. If anything it could be stated that the flexibility in packaging options allows for physically robust constructs. —Preceding unsigned comment added by 70.27.65.134 (talk) 21:58, 5 July 2010 (UTC)


 * Depends. If we are talking about the bare cells, then Li-ion are indeed more robust as they are in a metal shell, whereas the Li-Po is just contained in shrink wrap plastic.  However, the way the batteries are generally sold to the public - in some form of hard plastic shell, there is little difference. 86.180.84.187 (talk) 16:57, 25 March 2011 (UTC)

"Li-ion" and "Li-Po" are the same technology in different packaging. Both use salts dissolved in organic liquid electrolyte and a polymer separator for the electrolyte. The electrodes are identical. Li-PO has many sheets laminated together and sealed in a metalized pouch, where Li-ion cells are usually wound and inserted into a metal can. 12.207.23.130 (talk) 01:45, 16 May 2012 (UTC)

At first lithium polymer cells used a polymer based electrolyte. This made them very safe, but they were only useful for low discharge currents, since the polymer electrolyte could not conduct ions very well. Then the polymer was replaced with a separator and a gel, which brought higher performance. Finally, the gel was replaced with a liquid electrolyte, so the chemistry is identical with lithium ion. The terminology "polymer" started as meaning "polymer electrolyte," but now has come to mean "polymer package." — Preceding unsigned comment added by 50.73.46.101 (talk) 00:52, 16 February 2013 (UTC)

Here are some basic issues I am concerned with
1)The precise definition of "Lithium Polymer", "Lithium Ion", and "Lithium Ion Polymer", perhaps this warrants a disambiguation page. The additional problems introduced by "thin film Lithium" and "primary lithium" cells further confuses the reader.

2) The abbreviations for various batteries "Lipo" Vs. "Li Po" Vs. "LiPo". While at first one might think this does not matter... it does make a difference in the long run.

3) Life cycles... this is very confusing because some Lithium battery manufacturers insist that they're batteries have "virtually unlimited life", while other say they only get 300 cycles.

sony claims 500 cycles (http://www.ipoding.com/pdf/CXEYE.pdf) sanyo claims 500 cycles (http://www.sanyo.com/batteries/lithpol.cfm) Cymbet claims 70,000 cycles (http://www.cymbet.com/highlights.php)

see what I mean, this needs to be clarified

cheers. Leigh (March 5, 2005 8:44 PST)
 * What does "cycle" mean? One recharge is one cycle?


 * There is currently an issue with iPod batteries in that they last a little more than a year (the iPod has 1 year warranty). Is that a life expectancy limitation of the lithium batteries from the manufacturer or would this be an Apple marketing manipulation?


 * Can't comment on the Apple angle, but Li-po batteries should certainly last longer than a year. There is much debate about battery life, much of it just plain wrong.  I have lithium batteries that are 17 years old and are still going strong.  Their principal life limitation is a limit of around 500 full charge discharge cycles.  If you fully deplete and recharge your battery every day, then it will last around 500 days (a bit over a year and a half). 86.163.85.43 (talk) 09:50, 26 March 2011 (UTC)

Li-Poly Battery Quality Of 2006 In Portable Media Players
I bought a PMP (portable media player) in 2006 with a internal Li-Polymer battery (3.7V, 2700mAn). It lasts 13 hours on music mode and 5 hours in movie mode. - John Saturday Sept 30, 2006


 * This does not have much to do with the "quality" of the Battery and more on the Drain on the battery due to the device. To get a clearview on the "quality" aspects of the battery we would need to know the actual amp draw of the device in those modes to see how it differs from the listed 2700mAh, which has an implied 20 hour rate (2700mAh@20). Larek (talk) 14:31, 27 July 2009 (UTC)

Energy Density
"the energy density of Li-Poly batteries is over 20% higher than that of a classical Li-Ion battery" -- this is not true, according to my understanding. Anon - 11 September, 2005
 * Yes, a quick comparison of the energy density ratings on the Lithium-ion_battery page suggests you are correct. This needs to be fixed by either the deleting/rewriting that sentance, or changing the energy density ratings on the Lithium-ion_battery page or the Lithium ion polymer battery page. -- Roidroid 05:58, 13 August 2006 (UTC)

Series charging
Especially considering RC aircraft is mentioned, the main li-poly hazard in that industry should be addressed:

RC aircraft chargers typically charge all of the cells, in series, at once. While the sum voltage of the charge (16.8V for 4 cells) may be equal to the sum of the charge voltage intended for each cell, that does not guarantee that each cell has the same charge (4.2V); if one cell has fallen behind in voltage, another cell must gain the remainder; this overcharged cell could (and has been shown to) burst in to flames.

Mcmudge 19:04, 20 November 2005 (UTC)

Most of us now are using balance chargers these days (2013. — Preceding unsigned comment added by 121.72.203.100 (talk) 09:29, 2 June 2013 (UTC)

Safety issues in the Radio Controlled model world
Related to "Series charging" is safety in general. This is important. I'm not sure if this is the correct place to put it, though. Perhaps a small paragraph about use in the RC world and the dangers, then some external links to guides?

Many people have burned down their homes or lost their cars due to LiPos being charged with the wrong settings, or by charging a cell that has been over discharge (the pack as a whole, or a single cell in a series), from physical damage to the cells, or charging a 3.6v cell with a 3.7v cell charger.

I fear that someone getting into the RC hobby might look here for info and get the wrong impression. People read warnings all the time in today's society. They need to know that the safety issues here are very serious compared to NiCads, but obviously we don't want to turn this into some sort of LiPo guide for RC enthusiasts.


 * Why does the article say LiPo is less hazardous than Li-Ion, then? --Jibjibjib 22:32, 1 February 2006 (UTC)

Soupisgoodfood 02:06, 14 January 2006 (UTC)

I second everything above. LiPos have a tendency to EXPLODE VIOLENTLY when not charged properly

Kur 4 th_Ich

I third that. LiPo's are becoming popular in the RC cars, so I think that a section would be nice.


 * I feel like this article has been sanitized with respect to safety by someone who has a vested interest in Li-Poly batteries. 68.147.242.17 06:19, 5 August 2006 (UTC)

The danger is mostly with mishandling of the battery by the user. RC modellers often buy individual cells to custom construct the battery. Often safety equipments are left out in this process. Lipos are also soft and easily punctured during a crash especially if the model was a helicopter or airplane. Modellers also place extreme demand on their batteries. Sometimes over the manufacturer's specifications. For example, my Sony battery will run my laptop for about 80 minutes, but it will only run my helicopter for about 12 minutes. During the 12 minutes, the battery is subject to extreme hazardous conditions. After the 12 minutes run, the battery is quite warm/hot. It needs to be allowed to cool down before recharging or risk of explosion is greatly increased.

Today's lipo battery almost always includes a seperate parallel charging plug, pairing with a parallel charger, the dangers of series charging is done away with. A over charge/over dis-charge circuit can also be installed on the battery itself. This protects the battery from wrong charge voltage, over charging, short circuit and over discharge etc. NYCDA 15:55, 8 June 2007 (UTC)

If anyone who has a mind to write a safety section the 2007 MSDS for Lithium-ion Polymer batteries is available at http://www.batteryspace.com/prod-specs%5Cpolymers.pdf I think a small new section or addendum is warranted with regard to high-temperature mishaps (as well as mishandling) causing injuries/property damage. Kea2 (talk) 06:12, 19 August 2008 (UTC)

Electric Vehicle range claims
There was a claim of better than triple range in EVs in the "applications" section, with no explaination of how that could be the case. Unless someone has hard data on that it seems speculative to me and not encyclopedic but rather breathless marketing propaganda.
 * But I only say this because I'm a big oil supporter...so please....prove me wrong... —Preceding unsigned comment added by 69.47.118.64 (talk • contribs)

Li-Po Dangers
There should be a paragraph on the Sony battery scandal (Millions of OEM laptop batteries made by Sony were contaminated with metal shards due to substandard manufacture and a lot of them made notebooks explode and catch fire). I think those were Li-poly batteries, so this tech can be dangerous and is not fault-tolerant and this should be mentioned. 195.70.32.136 12:40, 13 November 2006 (UTC)


 * They weren't. 86.180.84.187 (talk) 17:18, 25 March 2011 (UTC)

How about the fact that when Li-polys burn they produce crystals which can mess up your lungs? Anyone want to verify that actually? I'm only getting this from the battlebots IQ authorities and they may just be overly cautious.--24.218.46.78 07:25, 16 April 2007 (UTC)

From testing I have been involved in I can state that the polymer actualy provides more fuel in combustion than the electrolyte in Li+ cells. Rez 21:34, 25 July 2007 (UTC)


 * Same electrolyte (though there is a bit less of the flammable bit, but it isn't eliminated entirely. The really big problem is that the chemical reaction in a burning battery generates its own oxygen (which is why you can't extinguish a burning battery - they even burn under water. 86.180.84.187 (talk) 17:18, 25 March 2011 (UTC)
 * This is wrong. The burning reaction of a lithium-ion battery does produce oxygen, but this oxygen is minimum. Just think about it. How much oxygen do you think there is in a battery that weighs 50 grammes, the typical weight of a cylindrical cell? Once the cell is ruptured, the internal layers and electrolyte are completely exposed to the ambient air, which provides the oxygen for combustion.
 * I can verify by laboratory experiments, and also by reports such as the Exponent report, that water is basically the best fire extinguisher for this kind of batteries, due to the additional cooling effect on the cell. There seems to be a confusion with lithium-metal batteries. Pure lithium is the most reactive metal, and therefore it reacts violently with most compounds. It is lithium metal the one that spontaneously combusts when in contact with oxygen or water, and therefore it is not recommended to extinguish lithium-metal fires with water or even CO2, with which it also reacts. The only recommended extinguisher is a class D, which consists of copper particles to smother the flames. But lithium-ion cells are a different story. They don't have metallic lithium, only lithium compounds, and the fire is closer to a class A fire, meaning burning of general combustible material like the electrolyte and the plastic separator.137.132.22.191 (talk) 05:46, 4 July 2014 (UTC)

Enviornmental Impact
I've recently been in a conversation trying to defend electric cars and one of the arguments made against them was the environmental impact of the batteries. I was under the impression that modern lithium polymer batteries had much less of an environmental impact than previous generations of rechargeable batteries, but I couldn't find much reliable information to back that up. Perhaps someone with expertise in the area could add a section titled "Environmental Impact" to the article to cover this.

--DreamTheEndless 16:17, 10 February 2007 (UTC)


 * Once Lipos have been discharged, it's safe to just drop them in the garbage can. NYCDA 15:31, 8 June 2007 (UTC)


 * Rubbish(!!). If they are physically damaged in the trip to the land fill, they will set fire to the rest of the garbage. 86.180.84.187 (talk) 17:23, 25 March 2011 (UTC)


 * The negative "Environmental Impact" happens when the battery is made. If you research how the batteries are made, you will find there is significant damage to the environment in the production of these batteries.  — Preceding unsigned comment added by 70.58.134.253 (talk) 21:20, 8 June 2012 (UTC)

life cycles
This type of batteries loses capacity with every single cycle. How much depends on the circumstances under wich the battery is used. Factors that make the battery lose more capacity are: temperature, discharge and charge currents and cut-off voltages during charge/discharge. A lithium ion polymer battery after 1000 cycles can NEVER have the original capacity. Actually, cycle durability is somewhat misleading. The battery can work even after thousands of cycles. To describe the durability of such batteries, a more precise formulation is needed. Something like: cycle count to 80% of the design capacity under ideal conditions. Jarda-wien 15:08, 11 May 2007 (UTC)


 * If my battery life is 10 hours, I only use it for 30 minutes from full charge, than charge it to full, does that count as a "cycle"? Should I wait to recharge the battery when it's almost dead to minimize the number of cycles and thus extend durability of my batteries? -76.20.60.255 10:47, 25 July 2007 (UTC)


 * What you are referring to has been known as the memory effect. The memory effect remains a big issue, but does only affect NiCd and NiMh batteries. Newer technologies (LiIon, LiPol or LiFe) are not prone to this. A battery cycle is defined as a full discharge followed by a full charge. If you run on battery for 30 minutes and recharge right after that, you can count one cycle after repeating this approx. 5 times... As long as the battery type used in your device is not NiXX-based, there is no problem with this behaviour. There is one disadvantage thou: the more you are nearing the full capacity, the slower the charging process gets. This means, that you can reduce time needed to charge your batteries by allowing them do discharge more. It is, however, not fully advisable to use the full battery potencial on a portable device in the winter. Low temperatures cause a higher resistance inside the battery. According to the Ohm's law the voltage of the battery has to drop in order to supply the current needed. As it is absolutely imperative for the cell voltage NOT to drop below 2V (in case of LiPol)! It is therefore safer to have your batteries charged at least to about 50% before exposing them to low temperatures. Simply said: the actual capacity of the battery drops in colder environments. Remember if your batteries were NiXX based, always using only 20% of their capacity would be a good way to kill them!--Jarda-wien 13:38, 4 November 2007 (UTC)


 * To answer the original question, a 5% discharge followed by recharge back to full capacity counts for VERY APPROXIMATELY 1/20 of a full cycle: i.e., you should get VERY APPROXIMATELY 20 times the number of cycles before wear-out. Having said that, information on this subject is scanty and lacking specific detail, and this is a pretty extreme case.  There is one way to get markedly longer service life, no matter if you discharge fully or partially before recharging: never charge to full capacity.  Charging to only 90-95% of capacity increases service life markedly.  The problem is, chargers typically do not provide this option.  I haven't found a single general purpose charger that does allow it.  The firmware in a good high-end notebook may allow programming the internal dedicated charger to stop at a prescribed limit short of full charge.  I know the firmware in my Lenovo X-301 does allow this. Fnj2 (talk) 20:02, 30 March 2011 (UTC)

The memory effect is a myth. http://en.wikipedia.org/wiki/Memory_effect It only happens in very specific situations "in which certain NiCd batteries gradually lose their maximum energy capacity if they are repeatedly recharged after being only partially discharged. The battery appears to "remember" the smaller capacity." This is not possible in a phone, laptop, iPod or other devices used in everyday life. —Preceding unsigned comment added by 78.143.78.8 (talk) 09:25, 12 February 2010 (UTC)


 * Completely incorrect. Memory effect depends on battery chemistry type.  Memory effect is a crippling defect in Nickel Cadmiums and makes them practically useless in real life situations such as cordless phones.  Nickel metal hydrides are much improved from a memory effect standpoint.  Your own reference which you quote illustrates how wrong you are.  There is no practical way to judge when a NiCad is "fully" discharged but not harmfully over-discharged; hence it is impossible to avoid memory effect in common use.  In a cordless phone, OF COURSE they will be repeatedly recharged after only slight discharge.  No one takes a cordless phone off the charger and continues to use it until it is completely discharged.  Duh.  It is returned to the recharging cradle after each use.  This is very severe duty and is guaranteed to produce very short service life in Ni Cads. Fnj2 (talk) 20:02, 30 March 2011 (UTC)


 * It is you that is completely incorrect. Most authorities on nickel-cadmium batteries have accepted for a long time that the memory effect does not exist except in a few very specialist sintered constructions manufactured exclusively for use in satellites.  Indeed, no users of the non specialist nickel-cadmium batteries had even heard of the phenomenon until marketing men seized upon it as a way of trying to sell the then new nickel metal-hydride (NiMH) technology.  When they first appeared, the Ni-MH offered no significant advantage at nearly five times the cost (having only a 20% capacity advantage over the former battery type).  The ability to sell on the memory effect was helped by the user experience with an unrelated problem where under used nickel-cadmium batteries appeared to exhibit a capacity reduction due the growth of short circuiting nickel whiskers within the cells, a phenomenon that also equally affects NiMH batteries.  Today, NiMH batteries have developed to the point where they are cheaper and have capacities of over three times their nickel-cadmium counterparts, so such marketing is no longer necessary.  But still the myth persists.


 * A reputable laboratory (I believe it was the Underwriter's Laboratory of America) tested run-of-the-mill nickel-cadmium batteries and were completely unable to reproduce any memory effect in any ordinary battery. They also tested the specialist satellite batteries and discovered the memory effect was reproduceable within five or six charge/discharge cycles, but only if the batteries were discharged to exactly the same level (which is what happened in the satellites).


 * There is a fair, if fragmented, discussion on the memory effect discussion page. DieSwartzPunkt (talk) 16:52, 18 May 2011 (UTC)


 * There are other flaws in Fnj2's arguments. The example of the cordless phone was not a very good one to choose because there are many cordless phones on the market where the batteries are continuously charged while the phone is in its cradle regardless of its state of charge.  This results in the batteries being over charged and suffering the mentioned vastly shortened life as a result.  This has nothing to do with any memory effect, of which I also accept as mythical for normal Ni-Cd battery types.  There is a practical way to tell when a Ni-Cd cell is fully discharged.  The full discharge point is when the cell voltage falls to exactly 0.00 volts.  Further discharge to a negative voltage is harmful.  This is not so useful for batteries of cells as differences in the exact capacity of the individual cells means that at least one cell discharges to 0 volts before the others.  For this reason, a battery is regarded as fully discharged once the terminal voltage falls to 0.8 volts per cell.  This voltage is regarded as high enough that an individual cell shouldn't have fully discharged to 0 volts in a battery that is still reasonably functional.  If an individual cell does reverse charge at this discharge level, then the battery has probably exceeded its life expectancy or may have other defects such as the presence of the nickel whiskers mentioned above.  Nickel whiskers are repairable by discharging a large capacitor into the individual cells which blows the whiskers away (rather like a fuse). 86.184.232.241 (talk) 15:22, 19 May 2011 (UTC)

Advantages/Disadvantages
A section with the benefits and trade-offs verses other technologies would be very useful. I came to this page to find out the effect of low temperature on this battery technology and no information was available. If someone has the data, a comparison chart showing things like energy density, dicharge rate, peak current, charge time, operating temperature, temperature derating etc. would be really useful. I have located an excelent chart of this type at http://www.buchmann.ca/chap2-page2.asp if someone who knows how to build charts in wiki pages wants to enter the data. Illuminant 16:49, 26 September 2007 (UTC)


 * That chart is too out-dated to be of any use. Many info provided are no longer correct. NYCDA 20:12, 30 November 2007 (UTC)


 * Also Isador Buchmann is a discredited source of information. Anything from that source is unacceptable as a Wikipedia reference or citation because it is entirely a self published source that does not have the backing of any reputable organisation.  86.180.84.187 (talk) 17:26, 25 March 2011 (UTC)

Wording suggestion: "current"
Re the following sentence... "Explosions can also occur if the battery is short-circuited, as tremendous current passes through the cell in an instant."

The meaning is very clear. But strictly speaking, to refer to "the amount of current in an instant" is incorrect. (Current is defined as the time rate of charge flow; so "a great quantity of current passing in an instant" would be like "a car going 80 miles per hour in a instant".)

This may be better wording:

"Explosions can also occur if the battery is short-circuited, as a tremendous current momentarily passes through the cell."

Lithium polymer batteries cannot explode. No pressure can be built up in the polymer case. You are confusing lithium polymer with metal cased batteries. They can catch on fire, they can puff up, but they can't explode. — Preceding unsigned comment added by 50.73.46.101 (talk) 00:43, 16 February 2013 (UTC)

Mark.camp (talk) 01:48, 27 December 2007 (UTC)Camper

Apple's portables
Apple say their MacBook Pros also have lithium-polymer batteries, but I don't know how to phrase that without it sounding really awkward and prone to misunderstanding. Semicolons (talk) 14:41, 13 May 2008 (UTC)

Overview, 4th paragraph, 2nd last sentence: Badly worded.
The 2nd last sentence of the 4th paragraph in the "Overview" segment is rather confusing to me.

The original reads: "In March 2005 Toshiba announced a new design offering a much faster (about 1–3 minutes) rate of charge."

I would recommend: "In March 2005 Toshiba announced a new design offering a much faster (by about 1–3 minutes) rate of charge."

My concern is for the section that is in brackets.

By the wording of the sentence, it sounds like the charge times were reduced to 1-3 minutes, however, as far as I know it would seem to me to be much more likely that it meant that charge times were reduced by about 1-3 minutes, instead of being reduced to 1-3 minutes from what the article states would normally take over an hour.

I don't know if I am correct in my assumption, however either way, I believe the article should be clarified to explicitly state wether the charge times were reduced by 1-3 minutes or reduced to 1-3 minutes.


 * Well, I DO know that you are INcorrect. A "breakthrough" which, for example, reduces the time required to recharge from 60 minutes to something between 57 to 59 minutes would get you laughed off any stage when you announced it.  The Toshiba design is indeed intended to recharge within 1-3 minutes.  20 seconds of googling would have told you this; for example, see http://www.dpreview.com/news/0503/05032903tosh1minbatt.asp  Hence, the statement in the Wikipedia article means what it says - quite clearly, I might add.  By the way, as far as I know, this innovation remains purely vaporware 6 years later, but that is another matter. Fnj2 (talk) 20:14, 30 March 2011 (UTC)

Thanks, Nabeel_co (talk) 04:36, 5 June 2008 (UTC)

In a device in which the direction of current flow is routinely reversed, the electrodes should not be defined as "anode and cathode". The terms "positive and negative" should be used instead. —Preceding unsigned comment added by 151.197.232.221 (talk) 19:35, 26 April 2009 (UTC)

Ampere-hours
Why does the section on the capacity rating not use the SI-approved abbreviation? I've not seen AHr for Ampere-hour in my life, but I'm not sure if this might not be prevalent in English texts (myself being in Germany). Is there any reason behind that, or should it be changed to Ah? Madcynic (talk) 19:18, 25 June 2009 (UTC)


 * You are correct, I have never seen AHr in the US either, however it looks like AHr has been removed from the article with no discussion post. Larek (talk) 14:35, 27 July 2009 (UTC)

power density
I changed it, look at this product: http://hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5730 It has 4200W/kg for a continous discharge. For a short period, it is even higher: 7100W/kg

I can verify that this isn't overstated. —Preceding unsigned comment added by 83.82.230.207 (talk) 21:33, 13 July 2009 (UTC)

Storage
No manufacturer makes any such claim for their batteries. This nugget comes solely from batteryuniversity.com, a site whose credibility is now in dispute (there is no such organisation), being run, as it is, by an individual solely to promote his book.

There is a discussion on lithium-ion battery and I suggest it is discussed there to avoid unnecessary duplication. 20.133.0.13 (talk) 14:47, 13 October 2009 (UTC)

The site you refer to is the popular-info disseminator for CADEX Electronics Inc. See the Cadex website. There they make clear that batteryuniversity.com is an educational website that offers practical information for battery users, and that the Buchmann book is fully-published online. It is not clear to me why you describe the site as "discredited" in the main section; I've always found it quite helpful.

I have found another source which recommends low-SOC storage for their Lithium Ion Polymer (Cobalt / graphite) cells: Sony Corporation. They recommend: "For these reasons, lithium ion rechargeable batteries should be in the discharged state when stored for extended lengths of time, and it is desirable that they be stored in a low-temperature environment." They show data for storage at 3.3 volts, a very low SOC.

The following link will allow you to download Sony's Technical Handbook on Li-Ion batteries, which includes data on Li-Ion Polymer (LiPos):  —Preceding unsigned comment added by 89.242.80.93 (talk) 13:17, 16 October 2009 (UTC)

Although BatteryUniversity.com is not an organization, its recommendation of storage charging Lithium-Polymer and Lithium-Ion batteries at 40% is also recomended (not using the same words) by Thunder Power (one of leaders in manufacture of Lithium-Polymer battery packs for model airplanes). Reference: http://thunderpowerrc.com/PDF/THPSafetyWarnings.pdf (alexcmag 12/12/2009) —Preceding unsigned comment added by Alexcmag (talk • contribs) 01:42, 13 December 2009 (UTC)


 * Unfortunately, Thunder Power are not the only company who have published information gleaned from BatteryUniversity believing it to be factual. Some very big names have fallen for the same trap, sometimes to their embarassment.  Incidentally, Thunder Power don't actually manufacture the batteries, but merely use third party batteries in their own battery packs.  It is the lack if any decent information from the battery cell manufacturers that allow charlatons such as Isador Buchmann (the man behind BatteryUniversity and his infamous and largely discredited book) to thrive. 86.180.84.187 (talk) 17:35, 25 March 2011 (UTC)

The Sony document linked above seems authoritative. I think the article text should be changed to recommend complete discharge (the graphs in the Sony document show discharge to 3.3V as the only way to maintain capacity in storage), and to incorporate the suggestions from page 57 of the Sony document (I've bolded the bits currently missing from the article): "When batteries will not be used for an extended length of time, they should be discharged, removed from the equipment and stored in a dry, cool place (avoiding warm places) in order to prevent rusting and degradation of battery performance. When storing batteries for one year or longer, they should be charged at least once a year or so in order to prevent overdischarge caused by the protective circuitry." A cool place seems to be sufficient and refrigeration is probably not necessary: the graphs in the document show no appreciable capacity loss at 23 degrees C, which is room temperature. C. Scott Ananian (talk) 18:57, 23 February 2010 (UTC)

Apple also recommends storing lithium batteries partly discharged and in a cool place: See http://www.apple.com/batteries/notebooks.html. And my own personal experience over several years with lithium batteries in devices from laptops to camcorders and phones bears this out. Long-term storage at full charge dramatically reduces service life. Heat makes it worse. My Thinkpad even includes software so that I can set the min and max charge points to preserve battery life (yes, the feature specifically says this is its purpose). By setting my laptop battery to stay between 25% and 40% when I'm going to use it plugged in, the battery has stayed like new. I recommend we get rid of the factual accuracy disputed tag, but I'm a wikinoob and have no idea (a) how to do this, and (b) the proper social protocols for doing so. CConrad (talk) 19:55, 10 June 2010 (UTC)


 * I have updated the article as per the discussions here to include the sourced information. I have, at the same time, reworded the section slightly to separate out the disputed source to make it more easily removable. As this discussion follows here and on the lithium-ion battery talk page I've removed the dispute tag from the section but left the source tagged as possibly unreliable. Cpl Syx  [talk] 15:02, 13 August 2010 (UTC)


 * Repeated storage fully charged may shorten the life of the batteries. I have several batteries that have always been kept fully charged (never partially charged).  As the oldest of them is a mere 17 years old andstill reports nearly original capacity, it is probably too early to tell.   If BatteryUniversity were to be believed, not battery could ever have a life exceeding 2 years. 86.180.84.187 (talk) 17:38, 25 March 2011 (UTC)

Cited sources suggest storing at 50% charged capacity, not 40. I have also generally heard 50% charged capacity at 3.85V per cell as the recommended storage level. I'm going to update the article to accurately reflect the values in these sources, and to avoid confusion. Wrend (talk) 05:39, 19 September 2011 (UTC)


 * I have removed it for two reasons. First, the ideal storage conditions are strongly debated with the most commonly quoted source being discredited (Battery University - a non existent organisation).  Second, you claimed that the manufacturers made this claim, but neither of the citations you provided are battery manufacturers - they build other manufacturers' batteries into their products.  The whole problem is that the battery manufacturers themseves are, for some reason, reticent to publish this sort of information, so there is no real citeable and verifiable source for any claim. 109.145.22.224 (talk) 16:48, 21 April 2012 (UTC)

If Battery University is't a good source, scientific literature might provide a better third party source. Referencing "Aging mechanism in Li ion cells and calendar life predictions" Broussely et al. (Journal of Power Sources, Volumes 97–98, July 2001, Pages 13–21) and "Ageing mechanisms in lithium-ion batteries" from Vetter et al. (Journal of Power Sources, Volume 147, Issues 1–2, 9 September 2005, Pages 269–281). Both state that SoC is a factor in self-discharge on the positive anode. 2001:400:613:18:0:0:0:722 (talk) 00:37, 28 May 2014 (UTC)

Not that important, but pictures...
The second picture down (at the current moment) is titled: experimental Li-Po battery made by NASA. There is a sticker on the side that clearly says Lockheed-Martin. i do not know why it does, but it does. —Preceding unsigned comment added by 129.119.157.124 (talk) 22:24, 7 June 2010 (UTC)
 * Lockheed-martin is a primary contractor for nasa- Nasa actually only manages and over-sees the majority of related projects they persue, and "farm" contractors to do the majority of the work. in this way NASA is able to use the corporate bidding structure to help keep costs down somewhat and benefit from the real-world experience many of the companies have in building things in the corporate real-world.*** this is why the majority of anything attributed to NASA was actually built by someone else. I have worked on a number of contract projects for differing companies and thus understand how this works..170.189.193.3 (talk) 15:28, 9 August 2010 (UTC)
 * I edited the caption. Roger (talk) 13:40, 24 January 2011 (UTC)

'Anode' and 'Cathode'
The terms 'anode' and 'cathode' cannot be used to describe specific electrodes in secondary cell systems. They are too vague as they switch ends between charge and discharge. See anode or cathode for a full discussion of the point. 86.183.25.124 (talk) 18:18, 4 April 2011 (UTC)

Technical Specifications
Inasmuch as the electrodes of a LiPo cell are often flat (thought perhaps flexible) plates separated by a fairly-thin dielectric, I wonder if this article should include information on the internal equivalent capacitance (not capacity) of these cells? Prof. Todd Carney / Southern Oregon University 18:18, 2 November 2011 (UTC) — Preceding unsigned comment added by Tcarney57 (talk • contribs)


 * I think it would be welcome - provided it's properly sourced of course. Roger (talk) 19:08, 2 November 2011 (UTC)

rename to Lithium polymer battery

 * The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 

The result of the proposal was moved. --BDD (talk) 16:55, 26 September 2012 (UTC) (non-admin closure)

Lithium-ion polymer battery → Lithium polymer battery – per WP:COMMONNAME Andy Dingley (talk) 21:14, 19 September 2012 (UTC)
 * Support per nom -- 76.65.131.248 (talk) 22:32, 19 September 2012 (UTC)
 * The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Self published sources.
As per WP:SPS:

and

The batteryuniversity.com website is run by one Isisdor Buchmann a completely discredited 'expert' in the field of lithium ion technology. That site was created solely to promote his equally discredited book on the subject. That both are promoted by Isidor Buchmann makes it resolutely self published material. That website wouild appear to have the backing of Cadex Electronics, a manufacturer of battery chargers so might appear to comply with the second requirement above. But as the CEO of Cadex Electronics is Isidor Buchmann himself, it totally fails to qualify as a 'reliable third party source'. Both the book and website (not unsurprisingly) promote Cadex Electronics who 'sponsors' both.

If most of the material contained in the book or on the website were true, no lithium based rechargeable battery could possibly have a life exceeding two years. That there are no shortage of examples well over a decade old totally undermines his claims.

That the battery manufacturers themselves are reticent to release much information on the technology leaves the way clear for charlatons to fill the void. 86.157.171.34 (talk) 17:21, 15 January 2013 (UTC)


 * Actually Buchman may qualify as WP:RS. See: Mike Musgrove. "Battery Pluses And Minuses." The Washington Post. Washingtonpost Newsweek Interactive. 2001. Retrieved January 15, 2013 from HighBeam Research: http://www.highbeam.com/doc/1P2-425884.html. --S. Rich (talk) 18:07, 15 January 2013 (UTC)


 * And how would that be? Many companies have been duped into accepting the dubious material pushed by Buchmann in his book and his web site.  It is somewhat strange that nearly all the dubious material contained therein is not available independantly from any other source particularly the battery manufacturers themselves.  Oddly most of the dubious material can be found on internet forums and newsgroup discussion sites (which is exactly where he trawled it all from).  And to prove the point, myself and a couple of colleagues invented a non existent limitation of the lithium-ion technology and dropped it into a few forums.  We circulated a claim that the technology would be longer lasting if a battery was not discharged below 30% charge.  Around a month later, the claim was (and still is) in the batteryuniversity website (and I believe in the 3rd edition of the book).  There was an unintended consequence in that at least one reputable manufacturer (HP) built a feature into a line of pocket PCs (their iPaq range) that warned the user when the battery reached 30% charge and advised that it should be charged.  HP do not make products with that feature today.


 * I cannot regard the Washington Post as a reliable third party support for Buchmann, but what of HighBeam Research? Is there any evidence that they are independantly underwriting Buchmann's claims, or are they just another company who are relying on the claims purely because they cannot find the information they require from any other source.  There are plenty of companies that have done just that.


 * Several producers of battery packs (but not the batteries themselves) make claims in their literature such as 'the batteries should be stored at 40% charge and 0 celcius for longest life'. The sole source for this claim is Buchmann's book and website.  Real world batteries cannot read and are therefore unaware of this limitation.  The oldest batteries that I am aware of that have always been stored fully charged and at room temperature are 17 years old and still exhibit near original capacity.  Another Buchmann claim is that the best storage temperature is 0 celcius but never lower.  Why?  There is nothing in a lithium ion battery that changes below freezing point (and there is certainly no water).  Once again, real world batteries are unaware of the limitation, though their available capacity does rapidly fall as the temperature drops, but that is a use limitation not a storage one.  The capacity recovers as the battery warms up.  But how many battery instruction leaflets have you seen that tell you that the battery must be kept above freezing point?   If you look at data sheets from battery manufacturers you get a different story.  Recomended max storage of 25 celcius (though it is somewhat buried), but no specified minimum temperature.  Buchmann's upper storage limit is 40 celcius, a temperature that is known to vastly shorten the life of any lithium battery (and is why it is adviseable to remove the battery from a laptop computer when running it on AC).  The problem is that Buchmann has set himself up as an 'expert' largely to promote his battery charger company (Cadex), but there really is nothing truly independant to support his claims to that role.  86.157.171.34 (talk) 12:48, 16 January 2013 (UTC)


 * Sorry, I should have wikilinked HighBeam Research. It is not connected with Buchmann.--S. Rich (talk) 15:31, 16 January 2013 (UTC)


 * So what? 86.157.171.34 (talk) 11:08, 18 January 2013 (UTC)

Solid state batteries vs. Lithium Polymer
I want you to understand two things:
 * The batteries now known as "lithium polymer" or "LiPo" are just lithium ion cells in pouch format, the electrolyte is still liquid (EC:DEC, for example).
 * There is current research on lithium ion cells using an actual polymer (plastic, semi-solid, gel) instead of the liquid electrolyte. This is what is known as a "solid state" battery, because all its components are solid. This kind of battery would have more merits to be called a "lithium polymer" battery. However, given that these cells remain experimental and there is no wide commercial use of them, they have not been named as such.

We need separate pages for these topics:
 * Lithium ion cell, which already exists and is getting better
 * Lithium polymer 1, this page which covers LiPo cells. The information on this page should be completely reduced to basically point to the lithium ion article.
 * Lithium polymer 2, a proper page describing the current research on batteries with polymer electrolyte.

The problem is what to call the latter two articles.
 * "Lithium polymer (LiPo)", "Lithium polymer (pouch)" could be used for number 1 above.
 * "Lithium polymer" may be reserved for number 2 above.

Another note is that number 2 above may even use lithium metal as cathode, thus not longer being a "lithium ion" cell, but an actual "lithium metal" cell. The implications of this are various, and not easy to summarise. With the cathode being lithium metal, the anode may also have to change, for example, to silicon (Si). The cell would still be "lithium polymer", but it may no longer be "lithium ion", further complicating the issue. I hope I can produce some references to support these views. It's unfortunate that the market took over the name "lithium polymer" so quickly that it created confusion among many users.137.132.22.190 (talk) 09:58, 23 June 2014 (UTC)
 * Okay, most of the information on this page now refers to LiPos, that is, lithium ion cells. Let us use a new page "lithium polymer electrolyte batteries", to refer to cells with solid polymer electrolytes, which may use lithium-ion or lithium-metal as one electrode.137.132.22.191 (talk) 09:06, 25 June 2014 (UTC)