There are different battery storage systems to suit different needs. So before you buy, make sure you know which type will work best for you.
An off-grid system is not connected to the electricity grid and therefore requires battery storage.
An on-gird systems do not need batteries and use common solar inverters and are connected to the public electricity grid. Any excess solar power that you generate is exported to the electricity grid and you usually get paid a feed-in-tariff (FiT) or credits for the energy you export.