The batteries do not tend to spontaneously combust. In vehicles there is much greater danger of physical damage causing a fire, and even there the incidence rat

The batteries do not tend to spontaneously combust. In vehicles there is much greater danger of physical damage causing a fire, and even there the incidence rate is a fraction of ICE fires. In a proper housing in a commercial/residential installation the risk should be far less than, say, having a car in your garage.