The mainstream battery types of energy storage battery are lithium iron phosphate batteries and ternary lithium batteries. With the solution of the energy density problem of lithium iron phosphate batteries, the proportion of lithium iron phosphate batteries has increased year by year.
The lithium iron phosphate battery has strong thermal stability and high structural stability of the positive electrode material. Its safety and cycle life are better than that of the ternary lithium battery, and it does not contain precious metals. It has comprehensive cost advantages and is more in line with the requirements of energy storage systems.
Energy storage battery focuses on battery capacity, stability and life, and consider battery module consistency, battery material expansion rate and energy density, electrode material performance uniformity and other requirements to achieve longer life and lower costs, and the number of cycles of the energy storage battery is generally required to be greater than 3500 times.
From the perspective of application scenarios, energy storage batteries are mainly used in fields such as peak regulation and frequency regulation power auxiliary services, grid-connected renewable energy, and microgrids.
In the composition of the energy storage system, the battery is the most important part of the energy storage system. According to BNEF statistics, the cost of batteries accounts for more than 50% of the energy storage system.
The cost of the energy storage battery system consists of comprehensive costs such as cells, structural parts, BMS, boxes, accessories, and manufacturing costs. The battery cell accounts for about 80% of the cost, and the cost of the pack (including structural parts, BMS, box, accessories, manufacturing costs, etc.) accounts for about 20% of the cost of the entire battery pack.
As a segmented industry with high technical complexity, battery and BMS have relatively high technical barriers. The core barriers are battery cost control, safety, SOC (State of Charge) management and balance control.
The production process of the energy storage battery system is divided into two sections.
In the battery module production section, the qualified cells are assembled into battery modules through the procedures of tab cutting, cell insertion, tab shaping, laser welding, and module packaging; in the system assembly section, the inspection is qualified The battery module and BMS circuit board are assembled into a finished system product, and then enter the finished product packaging process after primary inspection, high temperature aging and secondary inspection.
The value of energy storage is not only from the economics of the project itself, but also from the benefits brought by system optimization. After the economics of the energy storage project itself is close to the investment threshold, the energy storage system control and quotation strategy significantly affect the income of ancillary services.
At present, the electrochemical energy storage system is still in the early stage of development, the products and construction standards have not yet been perfected, and the allocation and storage assessment policy has yet to be introduced.
As costs continue to drop and commercial applications become more mature, the advantages of electrochemical energy storage technology become more and more obvious, and it has gradually become the mainstream of newly installed energy storage capacity. In the future, with the further emergence of the scale effect of the lithium battery industry, there is still a lot of room for cost reduction, and the development prospect is broad.