Commercial and industrial energy storage is a typical application of energy storage systems on the user side, primarily targeting industrial and commercial users such as factories, shopping malls, data centers, and industrial parks. Its core function is to utilize energy storage devices (such as lithium batteries) to store electrical energy during off-peak hours and release it during peak hours, thereby achieving peak shaving and valley filling, and reducing electricity costs. Furthermore, commercial and industrial energy storage can also serve as a backup power source, ensuring power supply during sudden power outages.
In the field of commercial and industrial energy storage, accurately understanding and mastering the various technical parameters of the equipment is crucial for system selection, design, operation, and maintenance.
DC-side parameters mainly revolve around the battery and the power conversion system (PCS), and are key indicators for measuring the energy storage capacity of the energy storage system and battery performance.
Battery Capacity (kWh)
Battery capacity reflects the maximum usable capacity of the battery and is a core indicator of the energy storage system's ability to store and release energy. In practical applications, the selection of battery capacity needs to match the power consumption duration requirements and rated output power of the energy storage system.
If industrial and commercial users wish to charge during off-peak hours at night and discharge during peak hours during the day to meet part of their electricity demand, they need to calculate the required battery capacity based on the peak-valley electricity price difference, electricity load, and desired discharge duration. Generally, the larger the battery capacity, the longer the energy storage system can provide power support, but the corresponding cost will also increase.
Cell Specifications
Cell specifications are one of the important indicators for measuring battery performance. They are usually measured in Ah (ampere-hours), representing the amount of electricity a battery can release under certain conditions (such as discharge rate, temperature, and termination voltage). Different cell specifications affect the battery's charge-discharge performance, cycle life, and safety.
High-capacity cells can provide more electricity, but may generate more heat during charging and discharging. When selecting cells, factors such as energy density, power density, cycle life, safety performance, and cost need to be considered comprehensively.
Depth of Discharge (DOD)
Depth of discharge refers to the percentage of a battery's rated capacity that has been discharged during the discharge process. In practical use, to extend battery life, a certain margin is usually left, and the battery is not fully discharged.
The recommended depth of discharge is 80%, meaning that the battery should stop discharging and begin recharging when it reaches 80% of its rated capacity. Excessive depth of discharge accelerates battery degradation and reduces cycle life.