Optimal Energy Management Of Li-ion Battery Energy Storage System Based On SOC

Under the dual threat of energy crisis and environmental crisis, the concept of the energy internet came into being, and quickly became the developing focus for all countries. As one of the essential elements of energy internet, the development of battery energy storage system must be unlimited under the current context. Small scale of current battery energy storage system is far from being able to meet the demand of energy internet, therefore the emergence and development of large-scale battery energy storage system has become a necessity. However, the current large-scale battery energy storage system still face many issues, such as the short using life, low efficiency, poor reliability and so on. This current requires we handle the design and management techniques of large-scale battery storage system. The main focus of this paper is to study the topology design and energy management optimization of large-scale battery storage system.Firstly, we master the using characteristics of lithium-ion battery by large of charging and discharging experiments. These conclusions provide the necessary theoretical basis for the design and management of lithium-ion battery energy storage system.Secondly, we detail introduce the ways of battery connection within a battery pack. After analyzing advantages and disadvantages of each connection way, we apply the concept of modular, use idea of grouping, sub-level and independent autonomous to design the topology of large-scale lithium-ion battery energy storage system.Then, we analyse the influence of the depth and rate of discharge for lithium-ion battery using life, and develop the optimization model of discharging efficiency of the large-scale lithium-ion battery energy storage system which based on SOC of each battery module. According to these, energy management strategy for achieving long using life and high efficiency operation of the system is presented in detail.Lastly, we give an example of operation through simulating. According to the optimization model of discharging efficiency of this example, we get some numerical results by using genetic algorithm, and analyse these results in further.Apart from the work presented above, summary and further prospect are stated at the end of the paper.