Exploding phones! - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: January 11, 2012, 09:38:50 am
content: I was just sent this link it is about phones blowing up and even killing people not sure how much is rubbish but it makes me wonder if we should move away from lithium cells and go back ti NiMh again.http://www.androidauthority.com/busting-the-myth-yes-cell-phones-can-explode-42582/

author: Rerouter
author_rank: Super Contributor
timestamp: January 11, 2012, 09:45:14 am
content: would just like to clarify that this is a case that comes from lithium cells overcharged or generally being rather abused,almost all phones (some chinese knock-offs excluded) have safety systems in the battery and the phone, the general denomenator in the issue is the knock off charger people buy because they are just so cheap, which can over time beat the safety systems into a barely effective state (high voltage ripple on wallwarts,etc), and cause the lithium to reach a state it wouldnt have under normal conditions,

author: Short Circuit
author_rank: Frequent Contributor
timestamp: January 11, 2012, 11:21:22 am
content: 5.6 billion cellphones in use, 13 of which have exploded by unknown reasons, and you want to go back to crappy nimh? Trust me, human life is not that valuableAlso, did you notice that none of this reports come with any statements regarding the authenticity of the phones, batteries & chargers involved...

author: saturation
author_rank: Super Contributor
timestamp: January 11, 2012, 11:31:55 am
content: Given the huge volume of cellphone and LiIon or polymer batteries, the number of fires is fairly small once the safety features are engaged.That said, Li Ion and polymer cells however still remain a fire hazard when manufactured improperly, which could occur by accident from reputable sources, consider fires with Apple products in the past, or transported without proper containment; it is now heavily restricted on airlines even for ordinary passengers.Since cellphones require bursts of power frequently, NiMH cannot match Li for in density. But for other gadgets with ever dropping power requirements, low self discharge NiMH are more attractive because its safer when abused, and potential for very long calendar lives compared to still unproven newer Li Fe P04. The newest eneloop variant can replace most any application that uses alkaline batteries, including emergency equipment.

author: G7PSK
author_rank: Super Contributor
timestamp: January 11, 2012, 12:04:47 pm
content: I actually was not worried about lithium cells in phones. It got me thinking about the the cordless drill I bought about a year ago, A Makita with a 3amp hour 18 volt battery pack that came with a twenty minuet charger, these batteries get quite a pounding. I must say that compared to Nicad or NiMh cells these units run all day on one charge instead of needing several packs on the go I get away with just the one and I am drilling 10 or 12 mm holes> I hardly ever get the corded drills out these days when before cordless drills were only good for a few small holes an 8 mm hole in 10mm steel would flat the battery of the Bosch drill I had previously. If one of these power packs went bang it would be like holding a grenade, and quite likely bring tears to your eyes.

author: Psi
author_rank: Super Contributor
timestamp: January 11, 2012, 12:14:40 pm
content: I've seen RC plane lithium packs quite literally bent at 30deg in the middle after a crash.Quite a scarey thing.There was a fire in NZ a year or so back where someones RC heli battery burnt down their workplace after catching fire hours after a crash. It had been left at work for the night.

author: ipman
author_rank: Regular Contributor
timestamp: January 11, 2012, 12:17:26 pm
content: The worst accident seen (by me, at least): a LiPO battery in a pocket, shorted with a bunch of keys. It exploded and catched fire inside the pocket. The owner needed several skin transplants.

author: amspire
author_rank: Super Contributor
timestamp: January 11, 2012, 12:32:27 pm
content: Quote from: Rerouter on January 11, 2012, 09:45:14 amBatteries can catch fire due to manufacturing errors. In 2006 Dell and Apple had to recall a total of over 5 million battery packs because the cell manufacturer Sony had let metal particles contaminate the cells and the recall warning stated that in extreme cases, the cells can catch fire.QuoteThe charger should not affect safety much, as all phones would have a Lithium Ion battery management IC which shuts off all charging when the voltage hits maximum. Now if the management IC shorts, and the battery internally has no secondary overvoltage protection, then yes you can definitely damage the battery. Ideally with Lithium batteries, there should always be two levels of protection in case there is a failure.Also if a battery discharges below the minimum, it can be damaged. Some battery packs and some chargers just refuse to charge the battery once the voltage has gone too low. Other battery packs and chargers will trickle charge the battery till it gets above the minimum and then do a normal charge. This approach is less annoying as we get the battery back to life, but it is riskier, as the battery could have been damaged permanently.Richard.

author: saturation
author_rank: Super Contributor
timestamp: January 11, 2012, 03:35:48 pm
content: In addition, Li Ion batteries can be damaged by accidents at a job site, and cause them to malfunction. Li Fe Po4 is supposed to provide less a hazard but the recent Chevy Volt fires have not occurred to cars without Li batteries.Li Ion is best when there is no recourse; for power tools I'm not sure its the safest choice as having multiple power packs instead of just one can do the same work; Ion and polymer have a 3-4 year calendar life span, after which you must buy a new pack, you cannot recondition it.NiMH can be 'reconditioned' electronically and can easily exceed 10 years of calendar life, if charged and treated properly, so its cheaper to run in the longer term. Per volt cost is about them same, a 3V 1AH LiIon cell is about $5, and to do the same with NiMH will cost about $3-5 too but the NiMH will be about 2-3x larger in surface area.

author: G7PSK
author_rank: Super Contributor
timestamp: January 11, 2012, 04:33:14 pm
content: I have heard that if you knock a nail though a lithium cell it will go of like a bomb I have never done the experiment, but would you get a bigger bang from a fully charged cell or does the charge state make no difference.

author: Neilm
author_rank: Super Contributor
timestamp: January 11, 2012, 07:46:28 pm
content: Quote from: amspire on January 11, 2012, 12:32:27 pmSome phones don't have management ICs - they used to put the intelligence in the charger module to reduce the cost of the phone. These would pose problems if a different charger was used.QuoteMost packs will have a protection module built in nowadays. (especially if they want to meet some of the regulations on Li-Ion batteries). The module should disconnect the output if the cell voltage gets too low.Quote from: G7PSK on January 11, 2012, 04:33:14 pmIt can happen, but some of the newer standards require cells to pass this test without exploding. I remember seeing a video on YouTube of some Americans who decided to try shooting a battery. 5 rounds and all they got were 5 holes in the battery pack.Neil

author: Balaur
author_rank: Unknown
timestamp: January 11, 2012, 08:30:45 pm
content: Quote from: Neilm on January 11, 2012, 07:46:28 pmBear Grylls used a cell battery to start a fire:

author: IanB
author_rank: Super Contributor
timestamp: January 11, 2012, 09:14:38 pm
content: Quote from: G7PSK on January 11, 2012, 04:33:14 pmIt won't explode unless it is in a confined space, but it might go off like a Roman candle if it's charged. The nail shorts out the electrodes and the short circuit produces heat. The battery also contains flammable organic electrolyte that escapes through the puncture hole and may well catch fire from the heat produced by the short circuit. The result is a hot flame with nasty fumes and possibly red hot bits of metal flying around.Some lithium ion cells like the traditional lithium cobalt variety are more prone to flame than other so called "safe" chemistry. But they all contain a lot of energy when charged and will do nasty things if shorted.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 11, 2012, 09:33:43 pm
content: Quote from: Neilm on January 11, 2012, 07:46:28 pmI have never seen this, but in any case no current smart phone that meets the EU and Chinese requirements to charge via micro-USB should have this problem. Charging from 5V requires an onboard charge management IC. That includes many of the phones pictured in that gallery. If the story is to be believed, faulty aftermarket chargers are not the only cause of failure.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 12, 2012, 02:01:05 am
content: You don't need modern lithium batteries to start a fire.Many years ago,when I was but a stripling lad,I worked at an Electronics/Electrical store.In the Electronics section we had what used to be called a "tea chest"( a plywood crate that tea was shipped in) for a waste bin.All sorts of junk,including shredded paper,flat batteries,etc were chucked into this thing,& dumped every couple of days.On this occasion,the Electrical Dept received a bunch of warranty return Lantern batteries back,& after checking them with a battery tester,they were dumped-----in our bin,as theirs was full.Sometime later,I noticed a burning smell,& on closer inspection,a small stream of smoke emanating from our bin!We dumped everything out on the floor,stomped on anything burning,then found the source,-------two Lantern batteries with the contact springs tangled so that the +ve terminal on one contacted the -ve on the other,& vice versa.The "dead" batteries still had enough "grunt" to make the terminals extremely hot.This caused the shredded paper to smoulder,& hence the smoke.Luckily,this all happened mid morning,& not at closing time,as we probably wouldn't have had a job to come to the next morning!I have since tried this trick with "flat" 9volt batteries (the little ones we all use ).They too,will get seriously hot!If ever I dump Batteries,I make sure I put some tape across the terminals.Of course, we are not supposed to dump them any more,so I guess that takes the problem away from me & gives it to the recycling people.VK6ZGO

author: sonicj
author_rank: Frequent Contributor
timestamp: January 12, 2012, 02:06:19 am
content: i haven't been able to reproduce the exploding LIPO trick intentionally (or unintentionally *knock on wood*). i have shot, stabbed, over-charged (12V @ maybe 5A connected to a single cell) and i get notta. i have a 2200mah 3-cell im willing to murder if someone can come up with a interesting destruction scenario...-sj

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 12, 2012, 02:56:26 am
content: Quote from: sonicj on January 12, 2012, 02:06:19 amDirect connection to mains, outdoors with video recording. (If necessary, connect a heater and power diode in series to prevent the breaker from blowing.)

author: G7PSK
author_rank: Super Contributor
timestamp: January 12, 2012, 09:59:59 am
content: How about putting the cell in the jaws of a spot welder 10,000 amps at 2 volts ought to do the trick.

author: mobbarley
author_rank: Regular Contributor
timestamp: January 12, 2012, 10:12:44 am
content: Quote from: sonicj on January 12, 2012, 02:06:19 amI am assuming you stripped them down to check for any protection circuit before shorting and stabbing?

author: saturation
author_rank: Super Contributor
timestamp: January 12, 2012, 12:57:31 pm
content: Lead acid fires: if you short the battery leads, the wire used could get red hot and ignite anything nearby, but by itself it should notexplode orignite. When overcharged the casing can bloat, crack and the gel or fluid bubble over, and if the pressure build high enough can burst.NiCD and NiMH: same as SLA above, but in addition, the casing can get very hot and melt down, leading a pool of hot goo and muck.Li chemistry: it will flare like fireworks without additional assistance.http://www.ainonline.com/?q=aviation-news/ain-air-transport-perspective/2011-09-12/airline-industry-wrestles-lithium-battery-issueSo given the above choices, the safest battery isn't Li, its risk is substantially reduced by all the safety electronics and additional guards built into it, but other chemistries simply cannot act this way even at the worse case scenario.Li can be the only choice for certain applications like cell phones, but if safety is a major parameter: to be used at home, unattended charging, use by technology challenged people, and the mAH require is within its capacity, NiMH is a safer bet. I put hand held power tools among the uses for NiMH too.

author: sonicj
author_rank: Frequent Contributor
timestamp: January 13, 2012, 03:39:01 am
content: Quote from: NiHaoMike on January 12, 2012, 02:56:26 amthat would probably do something exciting... maybe connecting the supply backwards would liven things up next time??Quote from: G7PSK on January 12, 2012, 09:59:59 amno spot welderQuote from: mobbarley on January 12, 2012, 10:12:44 amthese were high discharge RC cells so there was no protection circuitry attached.i believe its the oxygen mixing with lithium that causes the intense combustion reactions. no protection circuitry im aware of can patch holes.-sj

author: sonicj
author_rank: Frequent Contributor
timestamp: January 13, 2012, 04:05:13 am
content: Quote from: saturation on January 12, 2012, 12:57:31 pmthe gases providing that pressure are hydrogen & oxygen. add a source of ignition, like a shorted plate, and you'll get a nasty explosion! flooded LA cells are also an explosion risk. in addition to the gases inside of the cells, the gases vented through the caps is at risk of ignition.-sj

author: saturation
author_rank: Super Contributor
timestamp: January 13, 2012, 04:16:03 pm
content: sj, you are right. I wasn't thinking of it as the same energy or violence as Li, but not as benign as NiMH.Quote from: sonicj on January 13, 2012, 04:05:13 am

author: RJSC
author_rank: Regular Contributor
timestamp: January 13, 2012, 05:51:22 pm
content: Lithium Batteries are more than safe enough!Every weekend I use LIPO packs on my R/C airplanes, and without any fancy protection circuit on the pack, as consume electronics have.The motor controller on the plane just stops when they reach 3V per cell and the charger limits the current and voltage on charging.I've been using the LiPO batteries with no problems for over 6 years, and I've never seen one at the R/C club to blow up.Usually they just swallow when over discharged or maximum current capacity during discharge is exceeded.The new wave of electric cars, such as the Tesla Roadster, the Nissan Leaf, and the Mitsubishi iMiev Dave had on the blog in the past where all crash tested, and the one roadster already crashed at 160 km/h on the road an none caught fire.Only the Chevrolet Volt caught fire because its battery pack has liquid surrounding the cells to cool them which was not drained after the crash test, nor the battery was disconnected after the crash test and it caught firea week afterthe crash test.Several Nissan Leaf's, with air cooled batteries were tossed away and crushed on Japan during the Tsunami and none caught fire.The protection circuits on phone batteries are so damn picky that drawing 1 amp of a 700 mAh phone battery would make it cut off. I had to remove the circuit to use the battery discharging 1 amp into a motor, and it never exploded. It's still on the drawer after 2 years unused, probably approaching the end of the rated shelf life, since it came off an old phone.

author: RJSC
author_rank: Regular Contributor
timestamp: January 13, 2012, 06:15:43 pm
content: Quote from: mobbarley on January 12, 2012, 10:12:44 amStabbing shorts the cell internally, there would be noting an external protection circuit could do to avoid it.I was able to set one on fire (not exploding) on purpose by fully charging it and then shorting the terminals directly with pliers. I think that if you solder a wire and short it remotely, the wire resistance is enough to limit the current so that a quality cell with low internal resistance wouldn't catch fire.High performance R/C batteries have very low internal resistance.

author: saturation
author_rank: Super Contributor
timestamp: January 13, 2012, 06:40:28 pm
content: Yes, I am not dissing Li, I use them myself, but the issue remains if it was 'safe' it wouldn't be restricted by airlines or the postal service. No such restrictions exists for SLA or NiMH.http://en.wikipedia.org/wiki/Lithium_battery#Safety_issues_and_regulationQuote from: RJSC on January 13, 2012, 05:51:22 pm