[worstspotgain]

As a layperson, the first thing the title made me think of is "How safe can they get?" Let RESCI be the Risk of Explosion/Surge/Combustion/Inhalation. Here are some measures that are interesting to me that I can't really approximate when evaluating products:

- Incremental RESCI when buying from the cheapest 25% of vendors

- Incremental RESCI when drawing from the product population that shouldn't have passed QA

- Incremental RESCI when buying on AliExpress or random sites

- Incremental RESCI when dropping, hitting with a hammer, leaving in the sun, subjecting to a power surge

- Incremental RESCI from living in a dense neighborhood where dense people are buying from the cheapest 25% of vendors on AliExpress, occasionally dropping or hitting with a hammer, etc.

In the West, we have about a buck's worth of experience with residential electric service. By many measures, it's still much more dangerous than it should be.

[DaoVeles]

With a lot of new chemistry the risk of fire is greatly reduced. It seems to be an issue mostly with lithium based systems. Things like Iron or sodium based are much safer, energy density is also lower because of this but it is a reasonable trade off. Also tend to have much greater life time charge cycles. Potential to go tens of thousands of cycles rather than just a thousand or so.

[rootusrootus]

> an issue mostly with lithium based systems. Things like Iron or sodium based are much safer

The iron battery you are thinking of is a lithium battery. It is not the lithium that is a fire risk; lithium ion batteries do not contain metallic lithium. In an LFP battery the phosphate-oxide bond is much more stable and not subject to thermal runaway compared with e.g. cobalt-oxide.

[DaoVeles]

That sounds much better than the dribble I was spouting. Thanks!

[DennisP]

There's also someone building a factory to make iron-air batteries for grid storage. They're way cheaper than lithium or even sodium, with one of the most common materials on the planet, but only about 50% efficient. They're too heavy for vehicles, and have lower power output so aren't much good as peakers, but if you want four days of grid backup like we'd need with a 100% wind/solar grid, they're great.

https://formenergy.com/technology/battery-technology/