Batteries: how best to charge us?

BBC Radio 4 PM yesterday: Justin Rowlatt on battery developments (Starts 27: 47). Prompted by Elon Musk viewing a possible Bristol site for one of his car & battery “gigafactories”.
Prof Paul Shearing of University College London forecasts a tenfold increase in demand for batteries just in Europe, just to furnish new electric cars – meaning the UK would need seven gigafactories, at the current rate we build cars.
I’m glad that Rowlatt went on to cover the more generally important need for grid-scale battery storage, necessary for integrating renewables: even more battery manufacturing required!
Unfortunately this wasn’t the opportunity to discuss whether the Tesla model of selling people cars with permanently installed batteries, or home power storage batteries, is the right one; I don’t think it is. My preferences…
– EV batteries should be rented, never purchased, and standardised for all models/makes.
– All EVs get a “second slot” for instant range doubling with an extra battery.
– Domestic power storage should be rented: this avoids technical stranding, ensures bulk purchasing will bring down prices, gives poorer households a chance to enjoy the benefits, and keeps the supplier responsible for performance and breakdowns.