It's just one side of the equation, it is essentially the demand...

It's just one side of the equation, it is essentially the demand curve. In economic theory, if you cross that with the supply curve, you can estimate the quantity and price that buyers and sellers will settle on. Its just way too complex for a real world scenario like lithium to do in practice, but I'm sure a good estimate could be made.

Once the lithium price drops to to below the short-run marginal cost of production then mines will start curtailing or stockpiling output (basically, they won't sell anything if they lose money on every unit) and other short-term measures, and once it goes below the long-run marginal cost of production then mines will close or go on 'care and maintenance' and there will be job losses. All of this will impact the supply curve, driving prices up, because the demand still has to be satisfied.