Any civilisation that can produce a 60kWh battery or three per residence for gigantic EVs can trivially produce a 30kWh battery for overnight storage. Prices are at around $150/kWh at the cell level and assembly costs are plummeting, there's no real reason to think 12 hour Sodium-ion, Iron flow or ZnBR storage won't be available for prices close to the PV required to drive it daily.

It won't be needed because renewables can provide 70-95% of hours just by adding dispatchable loads even without adding more PHES or CSP, but it's not because batteries will be exorbitant compared to non-renewable generation options.