This isn't true for most lithium ion chemistries.

The liquid electrolyte is the thing that releases most energy when the battery burns, more than the anode and cathode. Some also have a very low self ignition temperature.

IIUC, the main problem with the current Li batteries is that the two plates can over time grow material that will 1) degrade performance; and 2) make it more likely to short circuit and catch fire. Similarly with electric car batteries after accidents where the battery is damaged, short circuits, and then catches fire.

So the main risk here would be the likelyhood of short circuiting under different failure scenarios.

Isn't the key difference that flammable solids have a limited reaction surface when they burn, whereas flammable liquids can be wildly unpredictable?

The energy "stored" in the light oil electrolyte of a battery is >10x more than the electrical energy or the energy released by reacting lithium alone.

An 18650 battery weighs ~50g and stores ~10 watt-hours. 10 watt-hours is 8,604 calories, enough to heat 50g of water by 172 C or 310 F. The battery would not even burn without a liquid electrolyte to ignite.

I wonder about the youtube videos of someone driving a screwdriver through a battery pack.

Is that the electrical discharge, then the lithium going off, then the electrolytes?