Operation strategy and optimization configuration of hybrid energy storage system for enhancing cycle life

Hybrid energy storage system (HESS) can take advantage of complementarity between different types of storage devices, while complementary strategies applied to configuration or operation have a significant impact on the battery cycle life. Therefore, in order to enhance the battery cycle life, this paper proposes an operation strategy and configuration technique for HESS and verifies it by a scenario of HESS tracking scheduling plan. Firstly, a linear rainflow counting method, which can be embedded in the optimization process, is proposed to quantitatively evaluate the cycle life of energy storage based on the half cycle identification model. Secondly, an operation strategy with the integration of the constraint of state-of-charge (SOC) recovery capability considering the dynamic degradation of energy storage cycle life during operation is proposed to ensure a certain charging and discharging margin for storages, thereby enhancing the cycle life of HESS. Thirdly, an optimization configuration model considering the operation strategy of HESS is established based on the minimum annualized investment cost. And the linearization techniques are used to transform the original problem into a mixed-integer linear programming problem, and the mathematical programming technique is adopted to solve the problem. Finally, the effectiveness of the proposed method is validated through case studies. The results of the case studies show that the use of the HESS operation strategy proposed in this paper can manage the VRB's SOC more efficiently, and the control effect of VRB's SOC is improved by 71.5 %. Meanwhile, by controlling the VRB's SOC, the cycle life of the energy storage in the HESS can be effectively improved, which reduces the annualized cost of the HESS by 53 %. © 2024 Elsevier Ltd