A Multi-Objective Co-Design Optimization Framework for Grid-Connected Hybrid Battery Energy Storage Systems: Optimal Sizing and Selection of Technology

Abstract

This paper develops a multi-objective co-design optimization framework for the optimal sizing and selection of battery and power electronics in hybrid battery energy storage systems (HBESSs) connected to the grid. The co-design optimization approach is crucial for such a complex system with coupled subcomponents. To this end, a nondominated sorting genetic algorithm (NSGA-II) is used for optimal sizing and selection of technologies in the design of the HBESS, considering design parameters such as cost, efficiency, and lifetime. The interoperable framework is applied considering three first-life battery cells and one second-life battery cell for forming two independent battery packs as a hybrid battery unit and considers two power conversion architectures for interfacing the hybrid battery unit to the grid with different power stages and levels of modularity. Finally, the globally best HBESS system obtained as the output of the framework is made up of LTO first-life and LFP second-life cells and enables a total cost of ownership (TCO) reduction of 29.6% compared to the baseline.

Development and Comparison of Rule- and Machine Learning-Based EMS for HESS Providing Grid Services

“…This factor is derived from the maximum full cycle of the NMC and LFP batteries. The LFP batteries have 3.33 times more cycle life [13]. The second term α 2 is the weight to minimize the total charge loss.…”

“…Moreover, the lower internal resistance of HP batteries makes it possible to reduce the size of the system [9]- [11]. Therefore, optimizing the size/cost/lifetime of the HBESS results in a superior system compared to a single-chemistry BESS [9]- [11], [13]. The general structure of a HESS with two battery technologies is represented in Fig.…”

“…However, they consist of two-stage solutions with a DC/DC conversion stage followed by a grid-tied bi-directional inverter. More details of the battery and power electronics and the system sizing can be found in [13]. Even though a HESS can be more performent compared to a BESS, its advantages can be maximized only with a welldesigned energy management system (EMS).…”

A Review of DC Fast Chargers with BESS for Electric Vehicles: Topology, Battery, Reliability Oriented Control and Cooling Perspectives

“…In contrast, those lacking cobalt (primarily LFP and LTO) have excellent cyclability and are considered quite safe, despite their low energy and power densities, with LTO being the most expensive one. LMO would be the poorest chemistry in terms of operational properties, while NMC would be the compromise chemistry that can be applied to any use or requirement [15]. Therefore, the selection and sizing of ESS must take into consideration the specific application and parameters of any LiB cell technology in the table.…”

“…Mass production of batteries, especially Li-ion, significantly decreased the cost, and stationary BESS is becoming more feasible. Considering [14,15], utility-scale BESS will be more profitable in the upcoming years even from the point of a conservative estimation approach. However, depending on the grid strength and system sizing, batteries may be subject to high C-rates, high number of cycling, and deep discharging which directly affects the overall lifetime of the battery unit [16].…”