Energy Storage Power Supply Q&A

Ah (Ampere-hour): An indicator reflecting the capacity of the battery. For example, 48V 100Ah indicates that the battery capacity is 4.8 kWh.

Nominal voltage and nominal ampere-hour are the most basic and core concepts of the battery.

Energy Wh = (Power) W * hourh = (Voltage) V * (ampere-hour) Ah

C (Battery discharge C rate): Reflects the battery charging and discharging capacity ratio; charging and discharging rate = charging and discharging current / rated capacity. It measures how fast the battery discharges. Generally, the battery capacity can be detected by different discharge currents.

For example, when a battery with a capacity of 100A·h is discharged at 15A, its discharge rate is 0.15C.

DOD (Depth of Discharge) Discharge depth: Refers to the percentage of the battery's rated capacity that is discharged during battery use. For the same battery, the set DOD depth and battery cycle life are inversely proportional. When improving one aspect of performance, other aspects of performance will be sacrificed. For example: Under DOD 80%, the lithium battery cycle life can reach 6,000 to 12,000 times.

SOC (State of Charge) State of Charge, representing the percentage of the remaining battery capacity to the rated capacity of the battery.

SOH (State of Health) Battery health status (including capacity, power, internal resistance, etc.) is the ratio of the capacity discharged from the battery when discharged from the full charge state at a certain rate to the corresponding rated capacity. In short, it is the ratio of the battery performance parameters to the rated parameters after a period of use. New batteries are 100%, completely scrapped at 0%, and according to the IEEE standard, when the battery capacity is lower than 80% of the rated capacity after a period of battery use, the battery should be replaced.

Three-stage Three-stage generally refers to a device that charges in three stages. Three-stage charging is an automatic charging process, and constant current, constant voltage, and float charging are the three necessary stages of three-stage charging.

BMS (Battery Management System) Battery Management System For battery status monitoring, battery balancing management, battery safety, and data communication. BMU (Battery Management Unit) Battery Module Energy Management System Battery module energy management system for multiple battery management systems.

 (Energy Management System) Energy Management System EMS is mainly used for internal energy control of microgrids, to maintain the power balance of microgrids for normal operation; to meet the on-site energy dispatching needs of small and medium-sized commercial energy storage systems; to meet the grid-side dispatching of large energy storage systems. From the level, BMS is the management of the underlying battery side, and EMS is the overall dispatch of the microgrid system.