Lithium-ion batteries contain significant amounts of, you guessed it, lithium. Lithium reacts violently with many other substances. If the battery is damaged or contains a fault, the result is lots of energy released (heat). This danger exists in all devices that contain a Li-Ion battery, which is just about everything these days.
Surely the chemistry doesn't matter much. Any energy-dense battery will contain a lot of energy by definition, and it seems improbable that there wouldn't be a way to make it come out faster than normal. This problem will only get worse as battery technology improves.
It matters only in so much that you needn't short a Li-Ion battery to have a violent discharge of heat energy.
Shorting any battery will cause it to heat up, but lithium is a potent alkali metal. It reacts violently (as in fire and possible explosion) with water. The moisture in your skin will do just fine. Contrast this with other battery chemistries such as nickel-cadmium, which are practically benign by comparison.
Here's a great video illustrating the results of dropping bits of various alkali metals in to a bathtub full of water:
Isn't the low energy density of NiCd batteries the main reason it's so friendly? According to the all-knowing Wikipedia, the best Li-ion batteries are over 4x more energy dense than the best NiCds, so there's over 4x more bang (and presumably 4x more desire to go bang).
It does appear that Lithium's reactivity with water is has much more energy release potential than the battery itself does, but from a bit of reading around on the all-knowing internet, this reaction is supposedly fairly gentle. "Lithium's density is only about half that of water so it floats on the surface, gently fizzing and giving off hydrogen. It gradually reacts and disappears, forming a colourless solution of lithium hydroxide."
Seems to me that if you physically abuse a battery, it's going to release the energy that it has stored. The only way to really avoid that is to not store so much energy. Or are there battery chemistries that can take abuse without releasing their energy?
Don't discount the chemistry. Sugar is more energy dense than a Lithium Ion battery and it can obviously be made to release its energy in a very safe and controlled manner. Alkaline batteries are almost as energy dense (although not rechargeable) and they are substantially more stable. You can physically abuse a normal battery without it discharging it's energy right?
It's the runaway reaction that makes Lithium ion batteries less safe. They require pressure vents and special circuitry to make them safe as they short out if fully discharged after which attempting to charge them is unsafe.
Sugar itself is not more energy dense than a battery, is it? You need an oxidizer to get energy out of something like sugar. In theory, sugar, gasoline, etc. are much more energy dense, but they need to be very carefully mixed with oxygen to release it all at once. That's why cars aren't generally bombs on wheels even though they theoretically contain sufficient energy to meet that description.
The thing with batteries isn't just the amount of energy that they contain, but that it comes entirely pre-mixed and ready for instantaneous release.
As far as normal batteries withstanding physical abuse, I don't know. I certainly wouldn't try puncturing or badly overheating a regular battery, and wouldn't be surprised if such treatment caused it to release what it has. I could, of course, be wrong.
Alkaline batteries can explode however it is quite different than the failure of Lithium batteries. If shorted out or exposed to current they can produce heat and hydrogen gas and because they are in a sealed metal canister they pop, sometimes violently. Note that this is different than Li-ion which can short out internally.
Considering how much more common standard batteries are, you can assume it is indeed pretty rare.
As for the energy density of sugar you're right that they're not really directly comparable but yeah I think it is more energy dense. Actually, wikipedia has a nice table for it:
I think we're actually in agreement here. My whole point was that the chemistry of how the energy is released is more important than the energy density.
Yeah, just some quibbling over details. My point is just that any battery that's as energy dense as a modern Li-ion battery will have similar potential to cause havoc if abused, and the problem will get worse as the tech improves because we'll be packing more and more energy into our pockets and backpacks. Maybe it is the chemistry more than the density, but I'm going to bet that any chemistry with comparable density would share the same problem. So, mildly different perspectives on the same ultimate effect, I think.
But you have to remember that the battery producers aren't especially interested in the safety of the battery (beyond a certain level)-- they care about price, capacity and re-usability.
At this point rechargeable lithium-based batteries are a more effective bomb than 90% of the things the TSA has banned - but I suspect we won't see them trying to take away laptops and phones anytime soon.
The TSA are a funny bunch. They've searched through my 80 year-old grandma's bags and confiscated her paint. Yet, when I mentioned that the metal detector failed to detect my solid metal watch, the agent said "it's ok - keep going".
Critical thinking is not part of the curriculum. There's a rule stating that your grandmother's paint must be confiscated, but no rule stating what happens if the metal detector is suspected defective.
On a recent flight he check-in person asked me if there was any lithium battery powered devices in the stow-away luggage. I think they are looking for things with big batteries like power drills and things like that, which presumably can pack a punch if they go wrong.
Edit: Not implying anything about a relation to phone use during takeoff and landing (BGR and Australian press release are vague), but I just found it curious.
Damaged lithium batteries catch fire whether the device is on or not.
The original reason why the "no electronics during takeoff or landing" regulation was adopted reaches back to the assumption that you can cause an airliner's nav system to go out of whack with radio signals emitted from consumer electronics.
As far as I know this argument has turned out to be pure FUD. However, once a law or regulation is in effect, it is unlikely to ever be rolled back again - this is probably the reason why they simply switched out the rationalization for it to something else: they now say that electronic devices could turn into deadly shrapnel during takeoff and landing.
Like so many "security" and "safety" related things today, the fact that they make you switch off your iPod but don't actually force you to pack it away safely requires a certain amount of cognitive dissonance of all parties involved.
I can't locate it, and wikipedia fully backs up the idea that electronics could interfere with Nav systems, however, I once read a compelling piece that lead me to believe different.
It had something to do with FCC regulations and how you could somehow bypass some system and get free calls, or calls could not be billed correctly, perhaps it was data, but it certainly was cellular related.
I can't seem to locate the information now.
At any rate, it does seem strange, as they cell towers themselves are not being asked to shut down, and they certainly broadcast much greater signals than the actual cell phone. This signal is rained over the entire aircraft 24/7.
The article that you mention (which I remember as well and also can't find) was basically saying how in theory a cellphone from a plane could hop from tower to tower much faster than they currently do if the user is in, say, a car, and that could cause some problems for the cell phone system.
I remember something along those lines as well, it has nothing to do with airline security and switching off electronic devices though. The issue here is that a 2G/3G device on a flying plane does reach a lot of cell towers simultaneously. The network is not designed for this, they pretty much assume that you're in reach of only a handful of towers at any given time - so the cell network could possibly be overloaded by thousands of people in the air trying to connect to many towers at once.
My major concern is that there's talk about using supercapacitors in portable devices, and notably in cars. The concern being that capacitors are specifically designed to discharge quickly, to the point that a shorted (IE purposefully connecting two terminals) capacitor quickly explodes.
The concern being that should we start filling the floors of hybrid vehicles with these, that we are essentially deploying fast moving bombs on our streets, roads and highways, and all we're going to rely on is faith that someone isn't going to put a switched connection between two terminals and wait till they're parked outside a police station, abortion clinic or elementary school and just flip the switch.
Lithium fires give off a number of toxic gasses like HF. Even if the fire was safely contained, my concern would be if the people on board were exposed to these toxins through inhalation. If a plane is recirculating cabin air, is there a anything a pilot can do to expunge bad air in these cases?
A plane does not recirculate all of the cabin air; it recirculates about 50%. Not ideal for the people but it's not like they are trapped with only the air that they have onboard. Also, the recirculated air is HEPA filtered. I would turn up my personal air nozzle if there was something like this in the future.
I do agree that the bite looks like a head, but it doesn't look the same as the one in the link above, especially when you take into account the missing "Steve Jobs" and "1955-2011".
I'd put it down to a freakish break line causing fragmentation around the bite. Backplate looks identical to mine (minus the damage).
Come on. Imagine a bearded Middle Eastern man with a device that's glowing red hot and looking like it's about to explode, on a passenger plane.
We live in an era where a few brown-skinned men praying on an airplane is enough to trigger passenger panic and the involvement of the FBI. Do you really think that, if the above happened and the passenger was unfortunately of the wrong race, that passengers would not immediately jump to the "terrorism" conclusion? In the last few years passengers have jumped to that conclusion for way less.
[edit] I'm not saying this would've meant throwing someone into Gitmo and throwing away the key. But you have to admit, if this happened to anyone of Middle Eastern descent, there's not a chance he wouldn't have been detained and subject to a barrage of investigations.
There is no way anyone who's phone battery ignited on a plane would be in prison, but beyond that, I'm just watching the arc of this thread bend towards dumbness and surprised to see you on it at all.
Do I think racism is alive and well all around this country? How about, just guess, and then we can keep the discussion off HN. A few years ago, this might have been a thread about battery chemistry. Now it's about the TSA. I have to believe you think that's sad too.
There's really not much meat to the topic, after all - lithium battery explodes... this is pretty much an everyday occurrence everywhere, about as newsworthy as "car crash on freeway" and "pen explodes in pocket". Spectacular and scary, sure, but this is a topic that is neither surprising nor particularly alarming to a bunch of gadget geeks.
Is it really any surprise that the bulk of the discussion is applying to meatier, more interesting/controversial tangents?
In any case, my OP is not really meant to be a lightning rod for Yet Another TSA Bash(tm), but rather just an exasperated, cynical quip.
I clicked through. You know it's "car crash on freeway". I didn't! One or two posts stabbed at clarifying --- if you could see them through the conspiracy fever stuff and the "derp derp held the wrong way derp" comments.
Anyways, I'm not trying to bag on you. My problem is with the whole site.
I find that since removing karma from comments made me less inclined to participate and read the comments here. My participation is way down.
My time is valuable and the comment scores, albeit a flawed metric, served a good purpose to filter out some of the less useful/insightful comments, I wish there was a toggle in the preferences that would allow people to turn it on per user.
I do have to agree. Traditionally HN has given token upvotes to cynical quips, jokes, etc, but the bulk of upvotes have always gone to really insightful comments. It's one of the things I enjoy about this community.
With the karma removed from comments, though, "witty joke with 7 upvotes" is now completely indistinguishable at a glance from "extreme insight with 100 upvotes".
I don't think it's realistic to expect people to stop joking about topic X, or making short quips about things... logically it makes sense to bring back some kind of way to differentiate these posts.
So go bury your head in the sand on some other site where conversations are limited to things like battery chemistry then. I don't think anyone would really care if you did that.
Don't be surprised though when the intelligent, compassionate people you're conversing with start noticing and commenting on the big bad police state that's been descending upon them.
Still. Why complain? Continuing a back-and-forth over a couple of silly comments certainly doesn't help. It doesn't make people go away or make them change to your liking. I guess the questions to ask are "What can I do?" and "How much is it worth?"
I mean, sure you can offer the odd complaint now and then and hope others are with you or you can organize others around a complaint to see where that gets you. You could go directly to the controllers of the board and complain.
The path of least resistance is always there though. If you don't like where you're at and you have no effective way of dealing with it, the best thing to do is to relocate.
Anyway, I should not have been gruff about it earlier. It could have been said more politely. So I do apologize for that.
Yowza. But yeah, lithium batteries do this sometimes on airplanes. Some of the smaller ones don't allow lithium batteries in the cabins for this very reason. That it's an iPhone isn't surprising in the least, and hardly front-page material.
My theory is that it was already compromised somehow (maybe defective), and the pressure decrease popped the container(s). And to people claiming OMG CASE MOD, look more closely. A crack goes right through the line that would form the glasses. It could be a mod, but I highly doubt it.
It seems plausible to me that when the phone came out of airplane mode, it increased radio transmission and/or CPU use. Due to some fault in one of those systems, the thermal throttling didn't kick in, and caused enough heat to melt open the battery. Perhaps the phone was jailbroken and overclocked?
I find it both amusing and telling that that is the only possibility you consider. Perhaps there was a manufacturing flaw in the battery, or it was damaged by dropping, yet 'blame the user' seems to be your knee-jerk reaction.
I started this by saying "Perhaps" the phone was jailbroken. I don't assume that is the case, I just provide it as a plausible option. Also notice that the Apple logo on the phone back has been modified.
