A Convex Cycle-based Degradation Model for Battery Energy Storage Planning and Operation

摘要

A vital aspect in energy storage planning and operation is to accuratelymodel its operational cost, which mainly comes from the battery celldegradation. Battery degradation can be viewed as a complex material fatigueprocess that based on stress cycles. Rainflow algorithm is a popular way forcycle identification in material fatigue process, and has been extensively usedin battery degradation assessment. However, the rainflow algorithm does nothave a closed form, which makes the major difficulty to include it inoptimization. In this paper, we prove the rainflow cycle-based cost is convex.Convexity enables the proposed degradation model to be incorporated indifferent battery optimization problems and guarantees the solution quality. Weprovide a subgradient algorithm to solve the problem. A case study on PJMregulation market demonstrates the effectiveness of the proposed degradationmodel in maximizing the battery operating profits as well as extending itslifetime.