| In order to realize the sustainable development of energy and environment,the renewable energy represented by solar energy and wind energy has been highly valued by all countries in the world.In terms of solving the instability of renewable energy power generation and large-scale energy storage problems,liquid-flow battery has attracted extensive attention due to its advantages of independent output power and capacity,long service life,deep discharge,high energy efficiency,no pollution,simple maintenance,low cost,safety and environmental protection,etc.Because of the problems of ion cross contamination and high price of ion exchange membranes in dual-fluid flow batteries,single-flow batteries have attracted much attention due to their advantages of single-liquid,non-membrane or low-cost microporous membrane,and become a new research direction.The zinc-nickel single-flow battery proposed by Jie Cheng et al.has been highly concerned for its long life,excellent battery efficiency,low self-discharge,good cycle performance,safety and environmental protection and other characteristics.In this paper,the simulation model and improved simulation model of zinc-nickel single-flow battery are established,and the influence of internal multiphysics on the polarization overpotential and terminal voltage of the battery is further explored.The work of this paper can be expressed as follows:(1)Based on the working principle of zinc-nickel single-flow battery,this paper establishes a prediction model of the external characteristics of battery electric reactor,aiming at the internal resistance loss of zinc-nickel single-flow battery and the effect of external parasitic loss on the battery performance.Batteries with a rated charge and discharge capacity of 300 Ah are studied and simulated under constant current charge and discharge mode.The simulation results are in good agreement with the experimental results,but there are still certain errors.The relative error between the voltage simulation value and the experimental value is basically controlled within 4 % when charging,and the relative error of the voltage at the end of the battery discharge reaches 8.7 %.(2)Based on the error analysis of the simulation model of zinc-nickel single-flow battery,the fixed value of ohmic resistance and polarization resistance in the original simulation model was changed to dynamic resistance using controlled current source,and an improved simulation model was further built for discharge process.Therefore,it accurately reflects the polarization trend in the actual operation.The simulation results obtained by simulation are compared with the experiments.The maximum relative error of the improved voltage simulation value of zinc-nickel single-flow battery under 100 A constant current discharge is 3.2 %,and the improved voltage relative error of the model end is lower than the original simulation during the entire discharge process.model,The results show that the improved model has higher accuracy and more accurate prediction of off-battery characteristics.(3)Based on the flow mass transfer,the conservation of charge and the reaction kinetics equation involving the reaction of hydroxide ion and zinc ion,a two-dimensional transient model of zinc-nickel single-flow battery is established.The correctness of the model is verified by comparison with experimental data.The effects of discharge current density,flow rate and ion concentration on the polarization overpotential and terminal voltage of the battery are investigated. |
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