Total global battery production seems to be 200-300GWh/year. If you want to buy approx 30% of total yearly output it's very unlikely you can negotiate your way to the head of the line. In fact, buying that much might raise global prices for batteries.

If I want enough solar panels and batteries to make my house off grid I can just write a check and the stuff shows up in a few weeks. But that doesn't scale upwards without limit. Eventually the limits on global supply kick in no matter how much you want it.