House fire -15 people exposed to toxic fumes

parametrek

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Apr 3, 2013
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578
crews found 200 pounds of lithium-ion batteries in the garage .... Investigators are now trying to determine what kind of business the homeowner was running.

Business? That isn't very much li-ion. Almost exactly 2000 18650. Just barely enough to make a useful DIY powerwall.

This is probably going to happen more often and more and more homes and businesses install batteries. Regions that makes it harder to sell electricity back to the grid are going to force more people to install them.

Thankfully there isn't very much fluorine in li-ion however. Mostly it is a component of the electrolyte as a stable salt:

The electrolyte is typically a mixture of organic carbonates such as ethylene carbonate or diethyl carbonate containing complexes of lithium ions. These non-aqueous electrolytes generally use non-coordinating anion salts such as lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate monohydrate (LiAsF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), and lithium triflate (LiCF3SO3).
source

Digging deeper this pdf says that LiPF6 can make up 1.8% of a battery's mass. Though that was in 2012 and things might have changed. Anyway the 200 pounds of battery works out to 1225 grams of fluorine. Of course it is extremely difficult to decompose a fluorine salt but it doesn't take much to cause problems. The lethal dose for a 10 minute exposure is 56 mg/m^3 source so 3-5 grams of gaseous fluorine would flood a typical attached garage to fatal levels.
 

idleprocess

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Feb 29, 2004
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dfw.tx.us
Business? That isn't very much li-ion. Almost exactly 2000 18650. Just barely enough to make a useful DIY powerwall.

This is probably going to happen more often and more and more homes and businesses install batteries. Regions that makes it harder to sell electricity back to the grid are going to force more people to install them.

I've pondered a DIY powerwall and one thing I immediately considered that pretty much none of the guides, tutorials, videos, etc mention is fire protection. Some mentioned heat management and thermal monitoring, but none seemed to include any sort of fire suppression or protection for the rest of the structure.

I thought that perhaps some sort of metal housing (i.e. the ubiquitous ammunition can) with a pressure vent packed with a heat-activated fire supression chemical would go some ways towards minimizing the damage one of these would do in the event of a fire. I've also wondered if simply burying them might help smother and contain any fires - in addition to being a great sink for waste heat.
 
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