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-   -   A very lucky pilot! (LI Iron Battery) (https://vansairforce.net/community/showthread.php?t=120338)

Reformed SeaSnake 03-05-2017 06:08 PM

Long time lurker here, finally paid the dues and since I have been looking at EarthX batteries for my build I'll throw in what I've learned:


Quote:

Originally Posted by Alan Carroll (Post 1154973)
Unfortunately I think the reality is a lot more complicated than this, and the terminology can certainly be confusing. Here's what I've pieced together so far (note: I could be wrong so please take this with a grain of lithium!):

Alan, you are correct. All currently available Lithium-based batteries are Lithium Ion. This includes currently available Lithium Polymer (LiPo) batteries. though Ionic Materials has produced a working LiPo battery that does not rely on any liquid electrolyte, their product is not yet available commercially. This battery was featured on a recent NOVA episode.

For anyone wanting to learn more about the chemistry of Lithium battery thermal runaway, the Royal Society of Chemistry has an interesting and pretty readable article here:

Thermal-runaway experiments on consumer Li-ion
batteries with metal-oxide and olivin-type
cathodes


I confess, I was a chemical engineer in a former life so my definition of "interesting" and "readable" may be skewed, however, there were a couple interesting takeaways:

1) All Lithium batteries can experience thermal runaway, either if they are overcharged or if they are subjected to high temperatures

2) LiFePO4 batteries are the safest of the current Lithium Ion batteries in the following ways
a) They require the highest temperature (~195 C) to initiate thermal runaway.
b) They evolve the least gas over the longest period of time (about 1/5 as much gas as Cobalt containing batteries)
c) The maximum temperature in thermal runaway is lower than for other Lithium battery chemistries (~400 C vs over 900 C for Cobalt containing batteries).

3) The gas evolved from all Lithium-based batteries contains a number of flammable constituents including Hydrogen as well as CO (not easily flammable, but dangerous).

4) maximum temperature during thermal runaway in LiFePO4 batteries is lower than the auto-ignition temperature of the evolved gas (~500-550 C), However, the maximum temperature of the common Cobalt containing batteries is well above the auto-ignition temperature of the gas. Hence, the much cooler YouTube videos with Lithium-Cobalt batteries.

All of that said, I am personally comfortable installing an EarthX battery in my airplane, either forward of the firewall or aft of the aft baggage bulkhead in a well-ventilated tail.


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