Talk:Lithium-ion polymer battery

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Here are some basic issues I am concerned with:

1)The precise definition of "Lithium Polymer", "Lithium Ion", and "Lithium Ion Polymer", perhaps this warrents a disambiguation page. The addtional problems introduced by "thin film Lithium" and "primary lithium" cells further confuses the reader.

2) The abreviations 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 clairafied

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?


Contents

[edit] 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

[edit] 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)

[edit] 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)


[edit] 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)

[edit] 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)

[edit] 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)


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)

[edit] 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)

[edit] 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)

[edit] 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. <edit>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)

[edit] 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."

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

[edit] 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)

[edit] 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.

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