Research On The Energy Storage System Of The New Energy Power Station

With the popularization of electric vehicles,a large number of decommissioned power batteries will be produced in the future.It is generally believed that the performance indicators can not basically meet the use standards of electric vehicles,when the current battery capacity is less than 80% of the rated capacity.If the battery is discarded directly,it will cause serious waste of resources.Also,the proportion of wind and solar power generation is increasing.However,there are a series of problems such as large power fluctuation and low reliability of power supply,due to its intermittence and randomness.Large-scale grid-connected will seriously reduce the security and stability of power grid.The application of large-scale energy storage system can smooth output power,improve power quality and increase system stability,but it can not be commercialized because of its high cost.The screening and reassignment of decommissioned energy batteries can be applied to power storage systems with relatively mild performance requirements,and then the decommissioned batteries are utilized step by step.It not only saves energy and protects the environment,but also excavates the surplus value of batteries,and reduces the cost of energy storage.In this paper,the decommissioned lithium-ion batteries of a rechargeable power station are selected for research.Firstly,the research status of equivalent models of cell monomer and module at home and abroad is introduced.Combining the internal working principle and external characteristics of lithium batteries,The Thevenin equivalent circuit model with high accuracy and simple structure is selected.By identifying the parameters of the model,The simulation model of single cell battery is established in Matlab/Simulink,and the accuracy of the model is verified by simulation;Secondly,Based on the simulation model of Thevenin equivalent circuit of energy storage battery,On the basis of Thevenin equivalent circuit model of single cell battery,According to the characteristics of series-parallel circuit,the series battery module,parallel battery module and series-parallel battery module models are established.In addition,the internal resistance consistency index of each cell was evaluated by a large number of charging and discharging cycle test data.Finally,the simulation analysis of the operation control technology of large-scale energy storage power plants participating in voltage control is carried out,and it is pointed out that the step-by-step battery energy storage system is an important research direction in the future.