No, you don't need a battery. A grid-tied solar system works perfectly without one: it powers your home by day and uses the grid at night, with net metering crediting your surplus.
A battery makes sense if you want backup power during outages, or if you want to store daytime surplus to use at night instead of exporting it cheaply. The trade-off is cost — batteries add a significant amount to the system price.
Many homeowners start grid-tied with a hybrid inverter and add a battery later, once they've seen their usage patterns and if outages or low export rates make storage worthwhile.
This is general guidance — figures vary by location, tariff, equipment and installer. Always confirm details for your own home before deciding.
