Otherwise known as explosives, rocket fuel, and most kinds of batteries.
Authorities said they used 32,000 gallons of water to extinguish the flames because the vehicle's batteries kept reigniting. At one point, Herman said, deputies had to call Tesla to ask them how to put out the fire in the battery.
Where I used to work, they had a machine shop that used to work with magnesium, before my time. Firefighters had a rule if they got a call: don't go in.
Another place I used to hang around during college was a robotics research lab. They had a bunch of 1st or 2nd gen l Li-Poly batteries, in pouch form, to run their little robots. I was told to never use a any of the fire extinguishers hanging on the wall if there was a battery fire. I don't remember the details, but either those particular extinguishers would catalyze the reaction and make the fire worse or they would boil and explode and just spread the fire around to more flammable stuff (maybe including your clothes). Supposedly there was a bucket of sand in case of emergency somewhere to isolate the fire and just let it fizzle out, but I never saw it and it may have been a hypothetical bucket of sand meant to calm nerves rather than a real bucket of sand to use in case of emergency.
They exist. They trade safety for energy-to-weight and energy-to-volume density.
People act like it's evil bogeyman keeping the masses from using electric cars. It's not. It's technology limitations, some of them surmountable given enough money today, but some of them because of hard physics-based theoretical limits.
Having to carry your own oxidizer as opposed to sucking it out of the air is one of those physics-based limits. A system that carries its own oxidizer will always weigh more than one that only needs to carry its own fuel. And it will almost certainly take up more space too. No amount of woke pseudoscience will magic that away.
Again: li-ion batteries do not contain oxidizers. The energy storage mechanism is not a fuel-oxidizer reaction. That would be a fuel cell, not a battery. The energy storage mechanism is the voltage potential difference between a lithium ion intercalated into graphite vs. a lithium ion intercalated into a mixed metal oxide.
Fire in a li-ion battery depends on the type. In any system where energy is stored, there is the potential for creating heat. In a battery, this can be from short-circuiting the anode and cathode, for example. So now you have a hot li-ion battery - the peak temperature depending on the nature of the short and the nature of the cell. Most electrolytes are flammable past an autoignition temperature. At above a given temperature, you can also start altering / reacting your anode and cathode. In high-nickel cells in particular, at high temperatures they can start to evolve free oxygen. The various other metals mixed with them such as cobalt, alumium, and manganese reduce the tendency to evolve free oxygen at high temperatures, but there always is some potential at some temperature.
EV fires are rare. Tesla fires average one per every 205 million miles, vs. 1 per every 19 million miles on average for vehicles in the US - and that's inclusive of earlier, more primitive designs, as well as being inclusive of things that can apply to any vehicle, such as burning due to arson or a house fire. The difference is that ICE fires do not make national news.
From freshmen chemistry I seem to recall that oxidation/reduction reactions are a generic term for two species exchanging electrons along a potential difference. Actual oxygen need not be involved in the oxidizer.
The "packed closely together" bit is the problem. Fuel and air don't spontaneously combust because while there's a lot of both, the contact surface area is relatively small and confined to the surface of the liquid fuel. Hence a gasoline spill can burn but won't explode. Diesel I don't belive will
From freshmen chemistry I seem to recall that oxidation/reduction reactions are a generic term for two species exchanging electrons along a potential difference.
You stated that li-ion batteries contain "oxidizers". Name the component that you think is an "oxidizer". Do you think graphite is an oxidizer? Do you think mixed metal oxides are oxidizers? Do you think hydrocarbon carbonates are oxidizers?
There are no oxidizers in li-ion batteries.
. Fuel and air don't spontaneously combust because while there's
I think the oxides are a product of an oxidation reaction that occurs when the battery cycles between charged and discharged states. The metal ions pick up or lose electrons moving from anode to cathode and back. One of those is an oxidation reaction. Hint: it's the one where the oxide reforms.
I think the oxides are a product of an oxidation reaction that occurs when the battery cycles between charged and discharged states.
You think wrong. They are formed at the factory and remain in their form (apart from any slow degradation processes over the battery's lifespan).
Li-ion batteries work by intercalation. Please look up that word before trying to continue this conversation, because I don't want to spend my whole evening dealing with the basics here.
Every single battery ever works by having one type of molecule/atom/ion give up an electron and another type of molecule/atom/ion picking up an electron.
Oxidation is defined as losing an electron. Whatever picks up that electron, either the anode or whatever is on the cathode via the electric circuit is known as the oxidizer of the ion/atom/molecule that originally gave up that electron.
Further, let's see what wiki says about Lithium Ion batteries in particular. Oh look:
The reactants in the electrochemical reactions in a lithium-ion cell are materials of anode and cathode, both of which are compounds containing lithium atoms. During discharge, an oxidation half-reaction at the anode produces positively charged lithium ions and negatively charged electrons...
"Fuel and oxidizer packed close together... otherwise known as explosives, rocket fuel, and most kinds of batteries."
What SPECIFICALLY are you definining as an "oxidizer" in a battery that "explodes" in reaction with "fuel"? Name the component. Are you calling mixed-metal oxides (aka, rocks) "oxidizers"? Are you calling graphite "oxidizers"? This is a very simple question here. What is it that you think is so eager to burn when it comes into contact with "fuels"
FYI, intercalation reactions happen every single day all around you, in that's how clays in the soil store nutrient cations in their interlayer space. Every day they're gaining and losing cations, due to weather, the action of plants, etc. How eager are you to call soil clays "oxidizers"? Are you afraid of having soil clays near fuel because they might behave like "rocket fuel and explosives?
And also FYI, there is a class of next-gen electrodes known as "conversion cathodes" (like iron fluoride) and "conve
Holy crap dude. It doesn't matter if the bond structure doesn't change. If a lithium ion loses an electron, whatever picks it up is by definition the oxidizer.
In a lithium battery, that's (by definition) the graphite at the anode and the other lithium ion at the cathode.
If the energy gradient is there, the reaction will occur spontaneously. An example of spontaneous reactions in nature is rusting: oxidation by atmospheric oxygen.
In solid rocket fuels and many explosives, there is a potential barrier that ne
Okay, after calling you out repeatedly for refusing to answer this very simple question:
What SPECIFICALLY are you defining as an "oxidizer" [aiche.org] in a battery that "explodes" in reaction with "fuel"? Name the component.... What is it that you think is so eager to burn when it comes into contact with "fuels"?... I'll loop back: name the specific battery component that you're calling "an oxidizer" that is "packed close together with fuel" in a manner akin to "rocket fuel and explosives".
The anode and the cathode packed closely together that will undergo a thermal runaway, chemically and thermodynamically, if not mechanically, akin to an explosion of a fuel-air mixture.
Fucking hell you are obtuse.
I answered your question three times. I (and other posters) explained to you several times why it's called an oxidation reaction even if no oxygen is involved and no molecular bonds change. You just got it in your head that some RightwingNutjob used a fancy scientific word wrong and no amount of po
And you're STILL refusing to answer what you're calling an oxidizer that you think is akin to "rocket fuel and explosives". Name the component, for god's sake. Are you calling both mixed metal oxides and graphite both "oxidizers"? And no, touching the anode and cathode together in a fully discharged battery will not cause any sort of reaction, they're not even remotely hypergolic with each other, they're inert; and the only "reaction" from contacting them in a charged cell is heat given off from a short
If you touch the cathode and anode together in a *charged* battery, by say poking a nail through it or squishing it with a hammer, then what happens, smart-ass?
And everyone keeps telling you that if an atom or ion gives up an electron, that's oxidation and whatever took that electron is the oxidizer. And if that electron being givne ip results in a lower energy state, then rhe reaction is exothermic and is subject to thermal runaway. Thermal runaway in a fuel air mixture is an explosion. In a controlled sce
The confounding between oxidation/ reduction and the half-reaction at an electrode against an electrolyte has been confusing teenage proto-chemists since before anyone in this conversation was born. At the molecular level they are the same thing, but when engineered into different assemblies, they become very different things.
But the stored energy remains dangerous. We've all made bangs and flashes from stored energy. Did you see the Formula-1 on Sunday, and
And you're STILL refusing to answer what you're calling an oxidizer that you think is akin to "rocket fuel and explosives". Name the component, for god's sake. Are you calling both mixed metal oxides and graphite both "oxidizers"? And no, touching the anode and cathode together in a fully discharged battery will not cause any sort of reaction, they're not even remotely hypergolic with each other, they're inert; and the only "reaction" from contacting them in a charged cell is heat given off from a short cir
The confounding between oxidation/ reduction and the half-reaction at an electrode against an electrolyte
What you're calling "the half-reaction at an electrode against an electrolyte" is the migration of intercalated Li+ to free Li+ in the electrolyte, reducing the screening charge in the electrode, causing electrons to leave. No change in oxidation states. Still Li+. Still sp2-bonded carbon in the anode and the cathode remains in its layered, spinel or polyanion form with no changes to its oxidation stat
You are talking to someone who would prepare aluminium filings as an energy booster for his home-made explosives.
I couldn't get the grain size small enough to have a noticeable effect, at least when experimenting in a town. I didn't have somewhere far enough away from being overheard to try with larger charges.
There are loads of webpages you can find that describe the Li-ion half reaction that is oxidation at the anode:
LiC6 --> Li+ + C6 + e-
That's an oxidation reaction. No oxygens are involved (not a fuel cell), but it's oxidation nonetheless.
More fundamentally, if the battery provides current, where do the electrons that make up that current come from? They come from the anode. Where does the anode get free electrons? From the oxidation reaction.
The Li in "LiC6" is not bonded to the graphite, but rather exists in the van der Waals gap between graphite layers as a Li+ guest ion. Consequently, there exists an extra electron to balance out the Li+. The reaction is of the form x A+ + x e- + [Z] Ax+[Z](sup)x-, and is known as an electron/ion transfer reaction, not a redox reaction. [Z] becomes a macroanion with mobile negative screening charges, akin to a capacitor. A redox reaction by contrast requires a change in the oxidation states of the reactant
If there was no oxidizer the battery would not work. Somewhere in the chemistry something is giving up an electron. Something else is absorbing that electron. The giver of the electron is being oxidized (even if oxygen is not involved) and the absorber is being reduced.
If the lithium is giving up the electron, then what compound is getting it? There is the oxidizer. Yes, the oxidizer gets reduced in the course of the chemical reaction.
If there was no oxidizer the battery would not work. Somewhere in the chemistry something is giving up an electron.
Lithium is an ion on both sides. It is intercalated on either end. As a lithium ion moves from the cathode to the anode during charging, the cathode loses a +1 (as the intercalated lithium leaves) and the anode gains a +1 (as new lithium intercalates). This creates a voltage differential. There is no change to the bonding structure of either the cathode or anode.
Some mixed metal oxides are rocks, but I wouldn't call LiCoO2 a rock. It's a metal oxide whose Co changes oxidation state from +4 to +3 during discharge, ie is reduced. It's the oxidizer because it takes that electron during discharge. I'm not sure why it's anathema call a solid object (or even a rock for that matter) an oxidizer.
Secondly, LiCoO2 is not used in EV batteries. The closest would be NCA or NMC, which are predominantly oxides of nickel (today cobalt is less than 10% of the metal content).
Third, mixed metal oxides are very much "rocks", and are indeed ores (though sulfates like pentlandite are more commonly used in battery nickel production - cobalt is often found in a solid-state solution in pentlandite). The only reason lithium is not commonly found in nickel/cobalt ores is that the processes that concentra
Considering one of those battery pack jump starters are capable of releasing 5V at 2A as a USB charger, or 12v at 800A to jumpstart a truck, it makes sense that they could release a their stored energy very quickly as heat when uncontrolled. And "release stored energy very quickly as heat" comes within the range of definitions of "explosion" -- which is very deceptive when you're looking at a colorful plastic rectangle with rounded corners, in a convenient faux-leather carrying case.
That was hard to find. Although admittedly the current practice of Tesla owners of deleting or removing all badging could make it a bit difficult to determine which model was on fire.
Around here our fire departments train with various EV dealerships who send trainers and dummy vehicles around. Mostly GM and Nissan because, ya know, Tesla doesn't have dealerships, but the principles are the same for all EVs with capacity higher than a Volt.
Then there's the instruction to shift it into park using the gear selector stalk. That will likely become obsolete when they move to touch screen everything.
"Take off your firefighter gloves, tap the car menu, the select gear, then select emergency, then swipe sideways three times to confirm...."
Wow, that page is bad. So first the firefighter has to figure out not just which model it is, but which model year too. For the S there is a choice of:
Emergency Response Guide - 2016+ Emergency Response Guide â" Model S Dual Motor â" 2014/2015 Emergency Response Guide â" 2014 Emergency Response Guide â" 2012/2013
The 2016+ one is a 31 page PDF file. The firefighting section is on page 22. Feel like that should be right at the top, but anyway... It says use water. Up to 3,000 gallons may be r
Here in my state NSW, Australia there needs to be an EV green label on the number plate similar to LPG for gas (not petrol) cars. I now see that itâ(TM)s probably to assist emergency responders.
When in doubt, use a powder extinguisher. Anyhoo, then best way to put out an electric car fire, would be with a dump truck of sand, but disposing of the system would still be unresolved, since the moment the sand is shoveled away, it can reignite.
The recommendation is to use water. Lots and lots of water.
The fire hazard from Li-ion batteries is not the lithium, but the electrolyte. Heat - either from external fire or internal short - causes the electrolyte to turn into a vapor, which causes cells to vent that hot, flammable vapor. That's what burns. Use lots of water to keep the batteries cool, which in turn keeps the electrolyte a liquid and inside the cells where it can't burn.
Putting sand on it might be the worst thing you can do, because that wi
I believe that for a large battery pack in a car. A little phone-sized one in a home or a lab...the instinct might be to use a faucet and that's just as bad as trying to put out a grease fire with water.
Powder based extinguishers are basically (hehe) baking soda and potassium bicarbonate. They generate co2 when heated and absorb some heat to smother small oxygen-breathing fires. I could ansolutely be wrong but I don't think they'll do a damn thing with a battery fire.
On an airplane, flight attendants have fireproof, armored bags they can put overheating phones or laptop batteries or tablets in. The fire can go its merry way insideu, though usually, it's smothered. Wonder if those are available for general public acquisition; would be good to have some around the house. And likewise fire depts.
It's not just an issue with electrical cars, but many other modern electrical generation devices. For instance, here in Europe, there are several countries where firefighters will not put out the fire in your house if you have PV cells on the roof. They will just let it burn, and try to save the neighbouring buildings. The same practice might be applied to electrical car fires in the future aswell.
Given the many different types of chemicals, reactions, metals etc. firefighters ca
No it isn't. But gasoline won't burn without oxygen and the surface contact area between a pool of gasoline and the atmosphere relative to the amount of gasoline is lower than the amount of contact area between cathode and anode in a battery relative to the amount of energy in the battery.
Li-ion batteries do not contain oxidizers. The anode is mixed-metal oxides (on higher-energy / nickel-based cells) or iron phosphate (lower energy density cells). The cathode is graphite with some silicon. The electrolyte is mostly simple hydrocarbon carbonates with dissolved lithium salts. Lithium ions (not metal) are intercalated in a mixture of the cathode and anode - discharged = cathode, charged = anode.
Where I used to work, they had a machine shop that used to work with magnesium
Any concentrated energy store (be it battery, fuel, flywheel, whatever) is likely to be dangerous in uncontrolled conditions, because it has to store a lot of energy in a small volume.
The only company that has demonstrated truly fireproof energy storage is Nikola [arstechnica.com]; I foresee a bright future for them.
Back when I was a copier repairman (not the good 'ole days) I got a call from a customer, it seemed that the machine was on fire. She wanted to know what to do (copiers use a powdered metal and run at high temperatures). I told her, if safe to do so, unplug it and roll it into the parking lot. It was a total loss.
There were some larger models that contained a built-in fire suppression system. Changing the bottles on those meant something bad had happened inside the machine.
Seen on a button at an SF Convention:
Veteran of the Bermuda Triangle Expeditionary Force. 1990-1951.
Fuel and oxidizer packed close together (Score:5, Interesting)
Otherwise known as explosives, rocket fuel, and most kinds of batteries.
Authorities said they used 32,000 gallons of water to extinguish the flames because the vehicle's batteries kept reigniting. At one point, Herman said, deputies had to call Tesla to ask them how to put out the fire in the battery.
Where I used to work, they had a machine shop that used to work with magnesium, before my time. Firefighters had a rule if they got a call: don't go in.
Another place I used to hang around during college was a robotics research lab. They had a bunch of 1st or 2nd gen l
Li-Poly batteries, in pouch form, to run their little robots. I was told to never use a any of the fire extinguishers hanging on the wall if there was a battery fire. I don't remember the details, but either those particular extinguishers would catalyze the reaction and make the fire worse or they would boil and explode and just spread the fire around to more flammable stuff (maybe including your clothes). Supposedly there was a bucket of sand in case of emergency somewhere to isolate the fire and just let it fizzle out, but I never saw it and it may have been a hypothetical bucket of sand meant to calm nerves rather than a real bucket of sand to use in case of emergency.
Batteries aren't a joke.
Your point is (Score:3)
hidden very well.
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Maybe that'll be Musk's next great invention. Self-extinguishing batteries.
Re: Fuel and oxidizer packed close together (Score:5, Informative)
They exist. They trade safety for energy-to-weight and energy-to-volume density.
People act like it's evil bogeyman keeping the masses from using electric cars. It's not. It's technology limitations, some of them surmountable given enough money today, but some of them because of hard physics-based theoretical limits.
Having to carry your own oxidizer as opposed to sucking it out of the air is one of those physics-based limits. A system that carries its own oxidizer will always weigh more than one that only needs to carry its own fuel. And it will almost certainly take up more space too. No amount of woke pseudoscience will magic that away.
Iron and air packed close together (Score:3)
One can always use iron as a fuel source. [phys.org] Even breweries [gizmodo.com] are using it.
Re: Fuel and oxidizer packed close together (Score:4, Informative)
Again: li-ion batteries do not contain oxidizers. The energy storage mechanism is not a fuel-oxidizer reaction. That would be a fuel cell, not a battery. The energy storage mechanism is the voltage potential difference between a lithium ion intercalated into graphite vs. a lithium ion intercalated into a mixed metal oxide.
Fire in a li-ion battery depends on the type. In any system where energy is stored, there is the potential for creating heat. In a battery, this can be from short-circuiting the anode and cathode, for example. So now you have a hot li-ion battery - the peak temperature depending on the nature of the short and the nature of the cell. Most electrolytes are flammable past an autoignition temperature. At above a given temperature, you can also start altering / reacting your anode and cathode. In high-nickel cells in particular, at high temperatures they can start to evolve free oxygen. The various other metals mixed with them such as cobalt, alumium, and manganese reduce the tendency to evolve free oxygen at high temperatures, but there always is some potential at some temperature.
EV fires are rare. Tesla fires average one per every 205 million miles, vs. 1 per every 19 million miles on average for vehicles in the US - and that's inclusive of earlier, more primitive designs, as well as being inclusive of things that can apply to any vehicle, such as burning due to arson or a house fire. The difference is that ICE fires do not make national news.
Re: Fuel and oxidizer packed close together (Score:1)
From freshmen chemistry I seem to recall that oxidation/reduction reactions are a generic term for two species exchanging electrons along a potential difference. Actual oxygen need not be involved in the oxidizer.
The "packed closely together" bit is the problem. Fuel and air don't spontaneously combust because while there's a lot of both, the contact surface area is relatively small and confined to the surface of the liquid fuel. Hence a gasoline spill can burn but won't explode. Diesel I don't belive will
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You stated that li-ion batteries contain "oxidizers". Name the component that you think is an "oxidizer". Do you think graphite is an oxidizer? Do you think mixed metal oxides are oxidizers? Do you think hydrocarbon carbonates are oxidizers?
There are no oxidizers in li-ion batteries.
Re: Fuel and oxidizer packed close together (Score:1)
? Do you think mixed metal oxides are oxidizers?
Really?
I think the oxides are a product of an oxidation reaction that occurs when the battery cycles between charged and discharged states. The metal ions pick up or lose electrons moving from anode to cathode and back. One of those is an oxidation reaction. Hint: it's the one where the oxide reforms.
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You think wrong. They are formed at the factory and remain in their form (apart from any slow degradation processes over the battery's lifespan).
Li-ion batteries work by intercalation. Please look up that word before trying to continue this conversation, because I don't want to spend my whole evening dealing with the basics here.
Re: Fuel and oxidizer packed close together (Score:2)
Every single battery ever works by having one type of molecule/atom/ion give up an electron and another type of molecule/atom/ion picking up an electron.
Oxidation is defined as losing an electron. Whatever picks up that electron, either the anode or whatever is on the cathode via the electric circuit is known as the oxidizer of the ion/atom/molecule that originally gave up that electron.
https://en.m.wikipedia.org/wik... [wikipedia.org]
Further, let's see what wiki says about Lithium Ion batteries in particular. Oh look:
The reactants in the electrochemical reactions in a lithium-ion cell are materials of anode and cathode, both of which are compounds containing lithium atoms. During discharge, an oxidation half-reaction at the anode produces positively charged lithium ions and negatively charged electrons...
htt [wikipedia.org]
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Let's go back to your original comments:
"Fuel and oxidizer packed close together ... otherwise known as explosives, rocket fuel, and most kinds of batteries."
What SPECIFICALLY are you definining as an "oxidizer" in a battery that "explodes" in reaction with "fuel"? Name the component. Are you calling mixed-metal oxides (aka, rocks) "oxidizers"? Are you calling graphite "oxidizers"? This is a very simple question here. What is it that you think is so eager to burn when it comes into contact with "fuels"
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FYI, intercalation reactions happen every single day all around you, in that's how clays in the soil store nutrient cations in their interlayer space. Every day they're gaining and losing cations, due to weather, the action of plants, etc. How eager are you to call soil clays "oxidizers"? Are you afraid of having soil clays near fuel because they might behave like "rocket fuel and explosives?
And also FYI, there is a class of next-gen electrodes known as "conversion cathodes" (like iron fluoride) and "conve
Re: Fuel and oxidizer packed close together (Score:2)
Holy crap dude. It doesn't matter if the bond structure doesn't change. If a lithium ion loses an electron, whatever picks it up is by definition the oxidizer.
In a lithium battery, that's (by definition) the graphite at the anode and the other lithium ion at the cathode.
If the energy gradient is there, the reaction will occur spontaneously. An example of spontaneous reactions in nature is rusting: oxidation by atmospheric oxygen.
In solid rocket fuels and many explosives, there is a potential barrier that ne
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Okay, after calling you out repeatedly for refusing to answer this very simple question:
What SPECIFICALLY are you defining as an "oxidizer" [aiche.org] in a battery that "explodes" in reaction with "fuel"? Name the component. ... What is it that you think is so eager to burn when it comes into contact with "fuels"? ... I'll loop back: name the specific battery component that you're calling "an oxidizer" that is "packed close together with fuel" in a manner akin to "rocket fuel and explosives".
and you STILL refusing to
Re: Fuel and oxidizer packed close together (Score:2)
The anode and the cathode packed closely together that will undergo a thermal runaway, chemically and thermodynamically, if not mechanically, akin to an explosion of a fuel-air mixture.
Fucking hell you are obtuse.
I answered your question three times. I (and other posters) explained to you several times why it's called an oxidation reaction even if no oxygen is involved and no molecular bonds change. You just got it in your head that some RightwingNutjob used a fancy scientific word wrong and no amount of po
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And you're STILL refusing to answer what you're calling an oxidizer that you think is akin to "rocket fuel and explosives". Name the component, for god's sake. Are you calling both mixed metal oxides and graphite both "oxidizers"? And no, touching the anode and cathode together in a fully discharged battery will not cause any sort of reaction, they're not even remotely hypergolic with each other, they're inert; and the only "reaction" from contacting them in a charged cell is heat given off from a short
Re: Fuel and oxidizer packed close together (Score:2)
If you touch the cathode and anode together in a *charged* battery, by say poking a nail through it or squishing it with a hammer, then what happens, smart-ass?
And everyone keeps telling you that if an atom or ion gives up an electron, that's oxidation and whatever took that electron is the oxidizer. And if that electron being givne ip results in a lower energy state, then rhe reaction is exothermic and is subject to thermal runaway. Thermal runaway in a fuel air mixture is an explosion. In a controlled sce
Re: (Score:2)
The confounding between oxidation/ reduction and the half-reaction at an electrode against an electrolyte has been confusing teenage proto-chemists since before anyone in this conversation was born. At the molecular level they are the same thing, but when engineered into different assemblies, they become very different things.
But the stored energy remains dangerous. We've all made bangs and flashes from stored energy. Did you see the Formula-1 on Sunday, and
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And you're STILL refusing to answer what you're calling an oxidizer that you think is akin to "rocket fuel and explosives". Name the component, for god's sake. Are you calling both mixed metal oxides and graphite both "oxidizers"? And no, touching the anode and cathode together in a fully discharged battery will not cause any sort of reaction, they're not even remotely hypergolic with each other, they're inert; and the only "reaction" from contacting them in a charged cell is heat given off from a short cir
Re: (Score:2)
What you're calling "the half-reaction at an electrode against an electrolyte" is the migration of intercalated Li+ to free Li+ in the electrolyte, reducing the screening charge in the electrode, causing electrons to leave. No change in oxidation states. Still Li+. Still sp2-bonded carbon in the anode and the cathode remains in its layered, spinel or polyanion form with no changes to its oxidation stat
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You are talking to someone who would prepare aluminium filings as an energy booster for his home-made explosives.
I couldn't get the grain size small enough to have a noticeable effect, at least when experimenting in a town. I didn't have somewhere far enough away from being overheard to try with larger charges.
Re: Fuel and oxidizer packed close together (Score:3)
There are loads of webpages you can find that describe the Li-ion half reaction that is oxidation at the anode:
LiC6 --> Li+ + C6 + e-
That's an oxidation reaction. No oxygens are involved (not a fuel cell), but it's oxidation nonetheless.
More fundamentally, if the battery provides current, where do the electrons that make up that current come from? They come from the anode. Where does the anode get free electrons? From the oxidation reaction.
Re: (Score:2)
The Li in "LiC6" is not bonded to the graphite, but rather exists in the van der Waals gap between graphite layers as a Li+ guest ion. Consequently, there exists an extra electron to balance out the Li+. The reaction is of the form x A+ + x e- + [Z] Ax+[Z](sup)x-, and is known as an electron/ion transfer reaction, not a redox reaction. [Z] becomes a macroanion with mobile negative screening charges, akin to a capacitor. A redox reaction by contrast requires a change in the oxidation states of the reactant
Re: (Score:2)
If there was no oxidizer the battery would not work. Somewhere in the chemistry something is giving up an electron. Something else is absorbing that electron. The giver of the electron is being oxidized (even if oxygen is not involved) and the absorber is being reduced.
If the lithium is giving up the electron, then what compound is getting it? There is the oxidizer. Yes, the oxidizer gets reduced in the course of the chemical reaction.
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Lithium is an ion on both sides. It is intercalated on either end. As a lithium ion moves from the cathode to the anode during charging, the cathode loses a +1 (as the intercalated lithium leaves) and the anode gains a +1 (as new lithium intercalates). This creates a voltage differential. There is no change to the bonding structure of either the cathode or anode.
And again, we come back to: do
Re: Fuel and oxidizer packed close together (Score:2)
Some mixed metal oxides are rocks, but I wouldn't call LiCoO2 a rock. It's a metal oxide whose Co changes oxidation state from +4 to +3 during discharge, ie is reduced. It's the oxidizer because it takes that electron during discharge. I'm not sure why it's anathema call a solid object (or even a rock for that matter) an oxidizer.
Re: (Score:2)
First, link [slashdot.org]
Secondly, LiCoO2 is not used in EV batteries. The closest would be NCA or NMC, which are predominantly oxides of nickel (today cobalt is less than 10% of the metal content).
Third, mixed metal oxides are very much "rocks", and are indeed ores (though sulfates like pentlandite are more commonly used in battery nickel production - cobalt is often found in a solid-state solution in pentlandite). The only reason lithium is not commonly found in nickel/cobalt ores is that the processes that concentra
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Self-extinguishing batteries.
All that's left is to start making the entire plane out of the same materials as the black box.
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Re:Fuel and oxidizer packed close together (Score:5, Informative)
https://www.tesla.com/firstres... [tesla.com]
That was hard to find. Although admittedly the current practice of Tesla owners of deleting or removing all badging could make it a bit difficult to determine which model was on fire.
Around here our fire departments train with various EV dealerships who send trainers and dummy vehicles around. Mostly GM and Nissan because, ya know, Tesla doesn't have dealerships, but the principles are the same for all EVs with capacity higher than a Volt.
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I'm pretty sure all EVs run at higher than one volt. [instantrimshot.com]
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Re: Fuel and oxidizer packed close together (Score:2)
Then there's the instruction to shift it into park using the gear selector stalk. That will likely become obsolete when they move to touch screen everything.
"Take off your firefighter gloves, tap the car menu, the select gear, then select emergency, then swipe sideways three times to confirm...."
Joke vehicles.
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Wow, that page is bad. So first the firefighter has to figure out not just which model it is, but which model year too. For the S there is a choice of:
Emergency Response Guide - 2016+
Emergency Response Guide â" Model S Dual Motor â" 2014/2015
Emergency Response Guide â" 2014
Emergency Response Guide â" 2012/2013
The 2016+ one is a 31 page PDF file. The firefighting section is on page 22. Feel like that should be right at the top, but anyway... It says use water. Up to 3,000 gallons may be r
Re: Fuel and oxidizer packed close together (Score:1)
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The recommendation is to use water. Lots and lots of water.
The fire hazard from Li-ion batteries is not the lithium, but the electrolyte. Heat - either from external fire or internal short - causes the electrolyte to turn into a vapor, which causes cells to vent that hot, flammable vapor. That's what burns. Use lots of water to keep the batteries cool, which in turn keeps the electrolyte a liquid and inside the cells where it can't burn.
Putting sand on it might be the worst thing you can do, because that wi
Re: Fuel and oxidizer packed close together (Score:2)
I believe that for a large battery pack in a car. A little phone-sized one in a home or a lab...the instinct might be to use a faucet and that's just as bad as trying to put out a grease fire with water.
Powder based extinguishers are basically (hehe) baking soda and potassium bicarbonate. They generate co2 when heated and absorb some heat to smother small oxygen-breathing fires. I could ansolutely be wrong but I don't think they'll do a damn thing with a battery fire.
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On an airplane, flight attendants have fireproof, armored bags they can put overheating phones or laptop batteries or tablets in. The fire can go its merry way insideu, though usually, it's smothered. Wonder if those are available for general public acquisition; would be good to have some around the house. And likewise fire depts.
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https://www.allhandsfire.com/F... [allhandsfire.com]
Hence firefighters unwillingness... (Score:2)
to put out electrical fires.
It's not just an issue with electrical cars, but many other modern electrical generation devices. For instance, here in Europe, there are several countries where firefighters will not put out the fire in your house if you have PV cells on the roof. They will just let it burn, and try to save the neighbouring buildings. The same practice might be applied to electrical car fires in the future aswell.
Given the many different types of chemicals, reactions, metals etc. firefighters ca
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Neither is gasoline you dumb shit.
Re: Fuel and oxidizer packed close together (Score:2)
No it isn't. But gasoline won't burn without oxygen and the surface contact area between a pool of gasoline and the atmosphere relative to the amount of gasoline is lower than the amount of contact area between cathode and anode in a battery relative to the amount of energy in the battery.
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Li-ion batteries do not contain oxidizers. The anode is mixed-metal oxides (on higher-energy / nickel-based cells) or iron phosphate (lower energy density cells). The cathode is graphite with some silicon. The electrolyte is mostly simple hydrocarbon carbonates with dissolved lithium salts. Lithium ions (not metal) are intercalated in a mixture of the cathode and anode - discharged = cathode, charged = anode.
You sound like you th
Re: Fuel and oxidizer packed close together (Score:2)
I sound like I'm telling a story about how first responders can be told to just stay the fuck away from things that are out of the ordinary.
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Any concentrated energy store (be it battery, fuel, flywheel, whatever) is likely to be dangerous in uncontrolled conditions, because it has to store a lot of energy in a small volume.
The only company that has demonstrated truly fireproof energy storage is Nikola [arstechnica.com]; I foresee a bright future for them.
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Batteries aren't a joke.
Yeah, no kidding: USS Bonefish fire [wikipedia.org].
Back when I was a copier Repairman (Score:2)
There were some larger models that contained a built-in fire suppression system. Changing the bottles on those meant something bad had happened inside the machine.