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
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 ne
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 a
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.
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
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
Re: (Score:3)
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 ne
Re: (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 a
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
Re: (Score:3)
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.
Re: (Score:2)
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: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