Economic Optimal Power Management of Second-Life Battery Energy Storage Systems

TL;DR

This paper presents an economic optimal power management strategy for second-life battery energy storage systems, addressing heterogeneity and degradation to maximize cost-efficiency and extend battery life in grid applications.

Contribution

It introduces a novel degradation-aware optimization model for second-life batteries, considering heterogeneity, temperature, and C-rate effects for improved management.

Findings

Cost minimization achieved through the proposed management approach.

Degradation costs significantly impact optimal operation strategies.

Simulation results demonstrate improved economic performance and battery lifespan.

Abstract

Second-life battery energy storage systems (SL-BESS) are an economical means of long-duration grid energy storage. They utilize retired battery packs from electric vehicles to store and provide electrical energy at the utility scale. However, they pose critical challenges in achieving optimal utilization and extending their remaining useful life. These complications primarily result from the constituent battery packs' inherent heterogeneities in terms of their size, chemistry, and degradation. This paper proposes an economic optimal power management approach to ensure the cost-minimized operation of SL-BESS while adhering to safety regulations and maintaining a balance between the power supply and demand. The proposed approach takes into account the costs associated with the degradation, energy loss, and decommissioning of the battery packs. In particular, we capture the degradation costs of the retired battery packs through a weighted average Ah-throughput aging model. The presented model allows us to quantify the capacity fading for second-life battery packs for different operating temperatures and C-rates. To evaluate the performance of the proposed approach, we conduct extensive simulations on a SL-BESS consisting of various heterogeneous retired battery packs in the context of grid operation. The results offer novel insights into SL-BESS operation and highlight the importance of prudent power management to ensure economically optimal utilization.