The invention discloses a combined type household
energy storage system and a combination control method thereof. The
system comprises N batteries to be combined, N battery management units corresponding to the N batteries to be combined, a
main battery, N connectors which are in one-to-one correspondence with the N batteries to be combined, and a
main battery management unit which communicates with each battery
management unit, wherein each of the battery management units is used for detecting the state information and ID
signal of a corresponding battery to be combined, each connector is used for allowing a corresponding battery to be combined to be connected to the power line of the
main battery in parallel, when the battery
management unit receives the state information and ID
signal of any battery to be combined, if a
battery capacity expansion
signal is obtained, when a condition that the
voltage difference between the
voltage of the battery to be combined and the
voltage of the main battery is in a preset range is judged, through controlling the connector corresponding to the battery to be combined to be connected, the battery to be combined and the main battery are connected in parallel, thus the capacity of the
energy storage system can be extended arbitrarily, and different needs of a user are satisfied.