On top of all of that, you need electrolysis to continually lower the water content out of the coolant for a few years. As the water content falls, so does the flashpoint of the coolant until it's eventually so low it can be ignited easily. Coolant is very flammable, but water is added to it that making it difficult to ignite unless you happen to have something like dendrites puncturing cells and creating uncontrollable electrical sparks that not only convert water into hydrogen and oxygen gas but also provide an ignition spark.
I do find it interesting that the a couple fires ago (the one that burned the Porsche too) there were comments pointing out the fire was stopped more easily than a lithium battery fire and was probably someone else, but when the NHTSA is investigating coolant fires that would fit that fire's observations suddenly it isn't something else any more. A few people here just disagree with everything. I've looked at every bit of evidence and tried to piece together what we know - fires and Tesla's admission of guilt - to come up with some kind of hypothesis. Coolant is one that works with a long drawn out set of circumstances, and to me the kicker that Tesla thought it was coolant last year was when they asked if teh car was parked at an incline. That doesn't make any sense unless they were worried about liquid inside the pack contacting the cells.
It doesn't really matter if coolant is the cause of the fires - if Tesla can recall batteries with dendrites without saying their batteries had a fundamental flaw by design it's best for everyone. Almost every manufacturer has been recalled for coolant leaks but none have been recalled for lithium ion battery design flaws like this. If the recall replaces my dangerous battery I don't care what they call it, and Tesla gets to keep lying. Everybody gets what they want.
------------------------------------------------------------------------------------------------------------
Moderator Note: This post was reported as being inaccurate. Citation needed.
------------------------------------------------------------------------------------------------------------
I’ve never tried this with a lithium cell, but I remember in inorganic chemistry my nutty professor threw elemental Mg in water and BOOM! Since Lithium (unsure if elemental or not) needs oxygen (Oxygen in dihydromonoxide <— causes cancer lol) to combust, I think you’ve got it backwards. Decussated Glycols, carboxyl, sugars in general are extremely difficult to combust. Fuel is largely the protons on organic compounds. Oxygen is just an electron acceptor and when you have these alcohol or ketone groups on organic compounds, especially on conjugated rings like benzene, there are less protons (hydrogen atoms) available to combust. Remember the number of hydrogens available on carbon chains is a determinant of combustibility. Same reason diesel has more combustion power over gasoline is it has longer carbon chain lengths. Gasoline burns more readily at room temp because it can more easily be aerosolized. Shorter length carbon chains stick less to each other, sort of like 1 inch lengths wet Spaghetti Is easier to pick up with a fork compared to full length spaghetti. And once you heat diesel up, it becomes extremely volatile and burns intensely because energy was added to favor combustion.
With the decussated coolant, it lends itself to be more crystallized. By virtue of crystallization, almost every molecule has a higher melting point temperature due to the fact that you have to overcome all the tight ionic bonds. This allows oxygen to more homogeneously spread throughout the fuel creating ideal conditions for combustion. The tight dipole bond of water also reduce combustibility of dihydromonoxide within the coolant. But vaporized water is effective at absorbing heat and thus cooling combustion. In fact, Diesel tractors and some BMWs inject water directly into the pistons to make more efficient combustion by cooling and increasing mass to the combustion mix but doesn’t contribute directly to combustion. The expansion of water to vapor yields a more powerful stroke (explain more about this shortly). The bond between oxygen and hydrogen is one of the strongest bonds in inorganic chemistry. So strong that it is one of the most potent greenhouse gases that exist. Arid vs jungle environments demonstrates this because the temperature delta in arid is extreme compared to jungle. One only needs to look to mars and see what I’m talking about. Predominately CO2 atm and yet the temp delta is still very extreme. Dihydromonoxide acts like the strongest molecular enthalpy shock absorber in existence. So much so that it expands 1000X volume during liq->vapor phase change. They build containment vessels in nuclear reactors that account for this volume change (Except RBMK reactors) because they keep coolant under pressure so that it can be heated above 100C without evaporating.
Highlights are:
1) crystallized or decussated sugars are difficult to combust due to lack of oxygen being able to reach fuel and less hydrogens on the carbon chain. Carbon can make 4 covalently bonds, and each carbon in benzene (Loops) is bonded 3 ways to carbon and once to hydrogen (fuel). Carboxyl, sugars, glycols similarly are less fuel dense (less hydrogens) than carbon chains.
2) dihydromonoxide cools combustion and retards the reaction at atmospheric pressure. It removes oxygen as it expands from liq to vapor, this is how wind is created in our atmosphere. Think blowing out a candle.
3) Once lithium ignites, the most effective way to stop combustion is to completely starve the batteries of oxygen. Like Jason previously stated, the coolant can slow the reaction as it spills into the pack. But as long as there is heat and punctured cells, you have a run-away process until all the lithium is oxidized.
4) Whether the coolant participates in combustion is relatively insignificant once lithium is ignited. The key is whether the coolant creates an environment conducive to starting combustion. Once started, there isn’t much else the coolant can due for either retarding or accelerating the oxidation of Lithium. Think of it like solid rocket fuel. Once it starts, it’s going to burn until the fuel is spent or exploded.
Just an extra thought, Tesla made it’s largest contribution to fire retarding its batteries in the model 3 with the foam injection. Essentially removing almost all elemental oxygen from the space combustion could occur. If the pack is damaged from a collision, all bets are off. But I think the reason we haven’t seen a model 3 spontaneously combust is due to this feature.
