Multifunctional Energy Storage Systems Research Articles

LiFePO4-coated carbon fibers as positive electrodes in structural batteries: Insights from spray coating technique

This study presents the fabrication of LiFePO4 (LFP)-coated carbon fibers (CFs) as a positive electrode component for structural batteries, utilizing a spray coating technique. The successful coating of CFs through this method demonstrated their usefulness as efficient current collectors. The electrodes obtained using this method underwent electrochemical evaluations. Throughout the extended cycling tests at C/7, the maximum specific discharge capacity reached 146 mAh/g, maintaining a 77% capacity retention after 100 cycles. In rate performance assessments at the faster C-rate of 1.5C, the capacity measured 123 mAh/g, with a retention of 96%. The application of spray coating emerges as a promising technique for electrode production in structural batteries, showcasing its potential for optimizing performance in multifunctional energy storage systems.

Multi-functional energy storage system for supporting solar PV plants and host power distribution system

Energy storage systems (ESS) will play a critical role in the ongoing development of the future electrical grid, especially as penetration of renewable energy generation increases. Since the costs of ESS are still high, it is imperative to research diverse control modes of ESS so as to use them in an effective manner, thereby offsetting their high costs. ESS technologies can diminish curtailment of renewable generators and provide much needed storage capabilities for supporting the grid, such as providing voltage regulation, relieving congestion, and improving power quality. This study develops six control modes for a battery ESS (BESS), namely, Current Limiting, Power Limiting, Load Leveling, Voltage Regulation, Power Factor Correction, and Simultaneous Real and Reactive Power Supply. The control modes are verified by simulation using a realistic utility 2.8-MW/5.6-MWh BESS and three solar PV plants connected to a power distribution grid. The study results demonstrate that the BESS functions properly in all the control modes. It can be used in all four quadrants of real and reactive power, i.e., it can provide any combination of real and reactive power amount within its rating for supporting the solar PV farms and the grid. The control modes enable effective operation of the BESS, which is a new tool to solve power system critical operational issues, thereby helping ensure the grid resilient, efficient, and reliable operation.

A Multifunctional Energy Storage System With Fault-Tolerance and Its Hierarchical Optimization Control in AC-Fed Railways

To better recycle the regenerative braking energy (RBE) and improve the power quality (PQ) in asymmetric AC-fed railways, a novel multiplex back-to-back energy storage system (MB2ESS) with fault-tolerance ability is proposed, where individual subsystems not only independently operate as self-controlled entities, but also collaborate with adjacent subsystems to resist system disturbances and local faults. On this basis, a hierarchical optimization control method with three-layer structure is designed for the flexible and effective operation of MB2ESS, including the global optimization layer based on finite state machine, the regional decision-making layer with event-driven distributed coordination controller, and the local execution layer via multi-converter autonomous control. It can be used to seamlessly switch different operation modes, coordinately manage the multidirectional transmission of RBE, dynamically control PQ optimization compensation, and rapidly perform fault response behaviors. Subsequently, through typical scenarios, comparative study, and field case of a traction substation in Beijing-Shanghai Railway, the feasibility and effectiveness of proposed scheme are verified. The engineering capability assessment results also show that this scheme can effectively make up for the structure and function deficiencies of conventional railway energy storage systems, which has well adaptability and application potential.

A comprehensive state‐of‐the‐art review of power conditioning systems for energy storage systems: Topology and control applications in power systems

Energy storage systems are pivotal for maximising the utilisation of renewable energy sources for smart grid and microgrid systems. Among the ongoing advancements in energy storage systems, the power conditioning systems for energy storage systems represent an area that can be significantly improved by using advanced power electronics converter designs and control techniques. Normally, the battery, flywheel, ultracapacitor and superconducting magnetic energy storage are the types of energy storage systems that typically require power conditioning systems for efficient bidirectional power flows. Compared to the previous review papers, this paper critically reviews the power conditioning system configurations and control techniques from the perspective of energy storage system applications in the power systems. First, the power conditioning systems are categorised into DC bus power conditioning systems and AC bus power conditioning systems based on the output voltage types at the connected point. Next, the topologies and control configurations of popular power electronics are comparatively analysed to highlight their advantages and power system applications. Moreover, the control configurations are discussed in terms of the popular applications of energy storage systems, that is, power backup smoothing, frequency regulation, voltage regulation and power quality applications. In addition, the latest developments in the energy storage system such as multi-functional energy storage system stacking, artificial intelligence for power conditioning system of energy storage systems and security of control of energy storage systems are critically analysed. Finally, the review is concluded by discussing industrial applications and future research trends for the power conditioning systems of energy storage systems.

Integrating Flexible Ultralight 3D Ni Micromesh Current Collector with NiCo Bimetallic Hydroxide for Smart Hybrid Supercapacitors

AbstractFlexible and lightweight supercapacitors with superior mechanical flexibility and outstanding capacity are regarded as an ideal power source for wearable electronic devices. Meanwhile, incorporating additional novel characters such as transparency and electrochromism can further benefit the development of smart supercapacitors. Nevertheless, the application of the commonly used planar‐structural current collectors is seriously restricted by their intrinsic properties such as poor rigidity, large thickness, and limited loading surface area. Flexible and ultralight current collectors with 3D architecture, high conductivity, and easy integration are believed to be the most appropriate alternatives to build high‐performance supercapacitors. In this study, a novel and scalable manufacturing technique is developed to produce a flexible and ultralight 3D Ni micromesh (3D NM) current collector for supercapacitor. Flexible smart supercapacitor integrated by 3D NM and high active Ni–Co bimetallic hydroxide (3D NM@NiCo BH) delivers a considerable rate performance (60.6% capacity retention from 1 to 50 mA cm−2). Furthermore, the fabricated hybrid supercapacitor device integrated with electrochromic functionality can visually indicate the energy level by a color display. This flexible electrochromic supercapacitor based on ultralight 3D Ni micromesh provides a novel insight into multifunctional energy storage systems for smart wearable electronic devices.

A novel voltage stability and quality index demonstrated on a low voltage distribution network with multifunctional energy storage systems

This work examines the effect of energy storage systems (ESSs) operation on the voltage stability and quality of the local power system. The variation of these two voltage dimensions is expressed in a collective manner by the novel voltage stability and quality index (VSQI). For the calculation of the VSQI, a complete voltage stability curve is required, and the coordinates associated with voltage stability and quality are identified. The distance between the abovementioned coordinates, that collectively indicates the effect of ESSs operation on the two voltage dimensions, is represented by the VSQI. The process for VSQI identification is repeated for each operating scenario, with the studied cases including grid operation prior to ESSs utilisation, grid support performed by a community level (CL) ESS, and grid operation with distributed (DIST) ESSs. The ESSs are powered by renewable energy sources (RESs), and a future scenario of 70% photovoltaic (PV) penetration was examined. Other ESSs applications presented in this work, include time-shifting of the energy produced by RESs, peak load shaving, and reducing the loading levels of transmission lines and of the substation transformer. The above stack of ESSs applications, highlights the multifunctional role of ESSs as support to the grid. A real low voltage (LV) distribution network located in south-east Queensland, Australia was employed for the study.

An Adaptable Engineering Support Framework for Multi-Functional Energy Storage System Applications

A significant integration of energy storage systems is taking place to offer flexibility to electrical networks and to mitigate side effects of a high penetration of distributed energy resources. To accommodate this, new processes are needed for the design, implementation, and proof-of-concept of emerging storage systems services, such as voltage and frequency regulation, and reduction of energy costs, among others. Nowadays, modern approaches are getting popular to support engineers during the design and development process of such multi-functional energy storage systems. Nevertheless, these approaches still lack flexibility needed to accommodate changing practices and requirements from control engineers and along the development process. With that in mind, this paper shows how a modern development approach for rapid prototyping of multi-functional battery energy storage system applications can be extended to provide this needed flexibility. For this, an expert user is introduced, which has the sole purpose of adapting the existing engineering approach to fulfill any new requirements from the control engineers. To achieve this, the expert user combines concepts from model-driven engineering and ontologies to reach an adaptable engineering support framework. As a result, new engineering requirements, such as new information sources and target platforms, can be automatically included into the engineering approach by the expert user, providing the control engineer with further support during the development process. The usefulness of the proposed solution is shown with a selected use case related to the implementation of an application for a battery energy storage system. It demonstrates how the expert user can fully adapt an existing engineering approach to the control engineer’s needs and thus increase the effectiveness of the whole engineering process.

All VN-graphene architecture derived self-powered wearable sensors for ultrasensitive health monitoring

The booming of wearable electronics has nourished the progress on developing multifunctional energy storage systems with versatile flexibility, which enable the continuous and steady power supply even under various deformed states. In this sense, the synergy of flexible energy and electronic devices to construct integrative wearable microsystems is meaningful but remains quite challenging by far. Herein, we devise an innovative supercapacitor/sensor integrative wearable device that is based upon our designed vanadium nitride-graphene (VN-G) architectures. Flexible quasi-solid-state VN-G supercapacitor with ultralight and binder-free features deliver a specific capacitance of ~ 53 F·g−1 with good cycle stability. On the other hand, VN-G derived pressure sensors fabricated throughout a spray-printing process also manifest favorably high sensitivity (40 kPa−1 at the range of 2–10 kPa), fast response time (~ 130 ms), perfect skin conformability, and outstanding stability under static and dynamic pressure conditions. In turn, their complementary unity into a self-powered wearable sensor enables the precise detection of physiological motions ranging from pulse rate to phonetic recognition, holding promise for in-practical health monitoring applications.

Approach for handling controller conflicts within multi-functional energy storage systems

The integration of modern energy storage systems (ESS) into power grids allows the implementation of different use cases (UCs). However, the simultaneous activation of such UCs could lead to potential conflicting behaviour. Hence, this study assesses the causes of conflicts within multi-functional ESS. A methodology for the identification and handling of conflicts is suggested using a model-driven architecture approach together with the well-known smart grid architecture model (SGAM). The main goal of this study is to demonstrate the usability of SGAM for the identification of potential controller conflicts. As a main result of this investigation, the SGAM alone does not allow the identification of all possible types of conflicts; it needs to be complemented by other models.

00/00817 A multifunctional energy-storage system with high-power lead—acid batteries

00/00817 A multifunctional energy-storage system with high-power lead—acid batteries

A multifunctional energy-storage system with high-power lead–acid batteries

Abstract A multifunctional energy storage system is presented which is used to improve the utilization of renewable energy supplies. This system includes three different functions: (i) uninterruptible power supply (UPS); (ii) improvement of power quality; (iii) peak-load shaving. The UPS application has a long tradition and is used whenever a reliable power supply is needed. Additionally, nowadays, there is a growing demand for high quality power arising from an increase of system perturbation of electric grids. Peak-load shaving means in this case the use of renewable energy stored in a battery for high peak-load periods. For such a multifunctional application large lead–acid batteries with high power and good charge acceptance, as well as good cycle life are needed. OCSM batteries as with positive tubular plates and negative copper grids have been used successfully for a multitude of utility applications. This paper gives two examples where multifunctional energy storage systems have started operation recently in Germany. One system was installed in combination with a 1 MW solar plant in Herne and another one was installed in combination with a 2 MW wind farm in Bocholt. At each place, a 1.2 MW h (1 h-rate) lead–acid battery has been installed. The batteries consist of OCSM cells with the standard design but modified according to the special demand of a multifunctional application.