[giwook]

For some reason I wouldn't exactly feel safe knowing there is a huge battery under my house that may combust at any moment.

[mschuster91]

That's the beauty with sodium ion batteries, they are generally considered to be even less flammable than already pretty safe LiFePO4.

[margalabargala]

Unfortunately that's not exactly true.

Aqueous sodium ion chemistries like Na-VPF and Na-tmCN are more fire-safe than lithium, but they're also not as developed/available yet.

Na-NMF, which is what a random off-the-shelf sodium cell is likely to be, is actually more flammable than LiFePO4.