The core hardware equipment of the home energy storage system includes batteries and converters. According to the degree of product integration, there are mainly two modes: integrated machine and split machine. The current market is dominated by split machines, but integrated machines are the development trend of the high-end market :
(1) Split unit, some AC-coupled products and DC-coupled products adopt the split-unit mode. The battery system and inverter system are provided by pack manufacturers and inverter manufacturers respectively, and then through the channels of integrators, dealers and installers reach the end user.
(2) All-in-one machine, the product is an all-in-one system including a battery and an inverter, usually an AC-coupled product. Upstream battery systems and inverters provide products as suppliers, and usually adopt the OEM model. The supplier's brand does not appear in the final product, and the sales and after-sales of the products are all borne by the brand owner.
According to the voltage level of the battery pack, it can be divided into high-voltage batteries and low-voltage batteries. The industry is showing a trend of switching to high-voltage batteries. The main purpose is to improve efficiency and simplify system design, but at the same time have higher requirements for battery consistency and BMS management capabilities. High-voltage batteries usually have a battery pack voltage above 48V, and multiple cells can be connected in series to achieve high voltage at the battery pack level. In terms of efficiency, with batteries of the same capacity, the battery current of the high-voltage energy storage system is smaller, which has less interference with the system, and the efficiency of the high-voltage energy storage system is higher; in terms of system design, the circuit topology of the high-voltage hybrid inverter is simpler , smaller size, lighter weight and more reliable. However, high-voltage batteries are composed of multiple batteries connected in series and parallel. The higher the voltage, the more batteries connected in series, and the higher the requirements for the consistency of the batteries. At the same time, it needs to cooperate with an efficient BMS management system, otherwise it is prone to failure.