Energy Storage Optimization Planning Considering Second-use Batteries

In recent years,the market scale of electric vehicle(EV)has been developed rapidly under the government's policy support in China.However,when the capacity of EV cell decreases to 80%,it will not be able to meet the appliance standards of EV.Predictably,it will enter the stage of massive recycle of EV batteries in the next few years.Although retired EV batteries can not satisfy the performance requirements in the field of electric vehicles,it can still play an important role in the field of energy storage.On the other side,the high cost of energy storage battery limits it's popularization and application in our country.Therefore,it is of great importance to use retired EV batteries with low cost into energy storage system(ESS).For the problem of second use of retired EV batteries,the capacity configuration and economy evaluation when they used for ESS are analysed in this paper.Main contents are as follows:Firstly,overseas and domestic research status of the second use of retired EV batteries are summaried.From the point of the research status,in the short-term stage,there will be of strong development potential for second-use batteries in the small and medium-sized energy storage applications,such as household energy storage,distributed generation and micro-grid.In the long-term stage,once the commercial chain is perfected,there will be a broad prospect for second-use batteries being applied to large and super large commercial energy storage system and power grid energy storage market.Secondly,the life and purchase cost of second-use energy storage batteries are analyzed.From the point of view of the whole life cycle of power battery,the process and cost involved in each life stage,such as application in EV,retired EV battery recycling stages and the second application in energy storage system,are analyzed.The equivalent cycle life of second-use batteries are estimated based on the rain-flow counting method.The calendar life of second-use batteries are estimated based on the relation curve of second-use battery capacity retention and cycle life.On this basis,according to the useful value of second-use energy storage system,a cost estimation method are presented,which laid a solid foundation for the optimal planning and economic evaluation of second-use batteries under different energy storage application scenarios in subsequent chapter.Then,the optimal planning and economic evaluation models are built for second-use batteries under specific energy storage application scenarios such as electric vehicle charging station,business park micro-grid and large-scale renewable energy generating station.The improved genetic algorithm(GA),particle swarm optimization(PSO)algorithm and artificial bee colony(ABC)algorithm are respectively used to solve the models,and the economical efficiency and purchase cost limit of second-use batteries are obtained.The modeling and simulation,analysis of examples and conclusion in this chapter have strong reference value for second-use energy storage in practical engineering application.Finally,Finally,combining the foregoing findings,the paper develops an application platform of optimal planning and economic evaluation for second-use battery energy storage system using Matlab GUI graphical interface,and compiles it as an independent executable file.The research of this paper provided a theoretical basis for the application of second-use battery energy storage system.