Safest battery for enclosed space

[Bluedog225]

What is the hands-down safest battery chemistry available to ordinary consumers currently? I’d like to have a small 48 V pack in an enclosed space in the house. I realize LiFePO4 are very, very safe. But I don’t want a possibility of venting a flammable gas. I think I can guard against the risk of electrical fire.

I’d rather avoid a discussion about how safe LiFePO4 are. I agree but am still looking for better.

Does such a battery exist commercially?

It looks like some of the newer salt-based batteries are coming online. For example below. Are there better options for long-term emergency backup?

Thanks

 

[740GLE]

In before all the comments about nickel iron batteries

 

[hwy17]

All of our available battery systems have some potential for venting flammable gas, even AGM if they fail.

 

[Bluedog225]

All of our available battery systems have some potential for venting flammable gas, even AGM if they fail.

Is that true?

Of course AGM can fail and vent.

 

[hwy17]

Is that true?

As far as I know, but I only consider a few batteries to be relevant and existing: FLA, AGM, LFP, NMC, LTO. All vent gases normally or in failure.