The rapid growth of electric vehicles creates significant opportunities for stationary energy storage through second-life battery utilization. This paper proposes a multi-timescale electricity cost optimization framework for second-life battery energy storage systems (SLBESS) in commercial buildings and validates it on a real deployed system. To address the complex challenge of commercial tariffs that include both energy and demand charges, our approach decomposes the problem by timescale. An upper layer uses hourly model predictive control (MPC) with a rolling horizon for long-term energy arbitrage, while a lower layer employs real-time control to mitigate short-term power peaks. Critically, the framework integrates empirically validated, health-preserving constraints for second-life batteries, including a restricted 15%-85% state-of-charge window and a 0.25 C-rate current limit, directly linking battery longevity to economic optimization. Comprehensive validation using 12 months of real-world operational data from a deployed SLBESS demonstrates a 28.6% electricity cost reduction compared to no-storage operation, outperforming baseline rule-based and Lyapunov optimization methods by 6% and 16.1%, respectively. The framework ensures sub-500 ms computation times, achieves a modest annual battery degradation rate of 1.20%, and delivers a 5.0-year payback period, highlighting its practical viability and performance in real-world commercial applications.

This paper proposes a natural watermarking approach for detecting cyber attacks in a renewable-rich microgrid (MG). The approach leverages the inherent variability of renewable energy generation to watermark the measurements feeding inverter-based resources (IBRs), enabling the IBRs to locally detect attacks. It detects cyber attacks by checking the statistics of the natural watermark exhibited in IBR measurements. It is physically interpretable, computationally efficient, and scalable for large-scale MGs. Its effectiveness is validated through pure-software simulations and real-time controller hardware-in-the-loop experiments in a MG test system.

The rapid growth of electric vehicles (EVs) presents both a significant opportunity and a challenge: What happens to batteries after they are no longer on the road? These "second-life" batteries, typically retaining 70%-80% of their original capacity, are ideal for less demanding stationary energy storage applications. This article explores the evolving standards and regulatory landscape in the United States for this repurposing. We examine the three primary reuse pathways, including the pack, module, and cell-level, and detail the critical safety and certification standards established by organizations, such as Underwriters Laboratories (UL) and the National Fire Protection Association (NFPA). The article identifies key challenges, including regulatory fragmentation, data accessibility, and economic hurdles, while drawing lessons from international approaches in the European Union and China. Finally, we propose a path forward for harmonized standards that can unlock the economic and environmental potential of second-life batteries, supporting a more circular economy and a resilient grid.

To enhance LCC-S inductive power transfer systems under varying coupling, this paper proposes a VIVC control strategy integrated with a dq-based Luenberger observer. Conventional VIVC is often constrained by wireless feedback latency and challenges in tuning controller gains for isolated receiver states. By employing a control-oriented dq model to characterize circuit coupling, the observer estimates mutual inductance in real time using only transmitter-side measurements. This eliminates communication delays and enables adaptive resonance. Simulation results verify that the proposed approach achieves Zero Phase Angle (ZPA) with near-instantaneous current settling and superior transient stability, providing high-performance dynamic control across wide operating ranges.

It is projected that, by 2030, the global stock of electric vehicles (EVs) will reach approximately 85 million units. When the capacity of EV batteries declines to 70-80% of their original performance, replacement becomes necessary, as the remaining capacity is inadequate to meet the operational requirements of automotive applications. Upon removal, these batteries retain significant material value and thus require proper recycling. However, their stored energy presents substantial safety risks, necessitating a controlled discharge process to mitigate potential hazards. This study presents the design and implementation of a system that integrates a boost converter with a single-phase grid-tied inverter to facilitate the safe transfer of energy from end-of-life (EoL) EV batteries to the electrical grid. The system was simulated in PLECS using a lithium-ion battery model and a non-ideal grid. The analysis shows that the system is stable and effective at transferring energy from the battery to the grid and heating the battery at the end of the process. This study identifies circuit operating conditions and control schemes that can enable the rapid, practical, and safe discharge of EV batteries without significant voltage relaxation.

The widespread deployment of photovoltaic (PV) inverters with digital control and communication systems has increased the power grid’s attack surface, making it more vulnerable to cyberattacks. This creates a need for locally implementable attack-detection methods that do not disrupt inverter operation. This paper therefore proposes an irradiance-driven natural watermarking approach for decentralized detection of false data injection (FDI) attacks on inverter terminal measurements. The approach leverages irradiance-driven DC-link voltage variations to watermark the inverter outputs, generating a non-removable signature in the true measurements. The proposed method is evaluated using a real-time hardware-in-the-loop model of a three-phase grid-following PV inverter that captures PV-array and grid-connection dynamics. Implementation robustness is further assessed on a separate hardware grid-forming inverter testbed with non-idealized components. In the tested cases, the detection model identifies noise-injection and replay attacks within 15ms, while otherwise undetectable model-based attacks are revealed when DC-link voltage variations between 5% and 10% occur. These experimental results demonstrate that irradiance-driven natural watermarking can reveal FDI attacks without affecting normal inverter operation.

Electric vertical takeoff and landing (eVTOL) aircraft have gained widespread attention in urban air mobility services recently. In the design of eVTOL aircraft, the powertrain system significantly impacts its performance and cost. This paper systematically describes a conceptual design and optimization methodology for eVTOL aircraft from the powertrain perspective, emphasizing its influence on overall aircraft performance and cost. The powertrain modeling methodology is achieved by considering a set of converter topologies and cutting-edge component technology, including wide-bandgap semiconductor devices, high-power-density passive components, and thermal management. Apart from that, a hybrid optimization algorithm is used in this paper to facilitate a rapid global search. Los Angeles has been selected as the example city for this study. A case study with a 30 km cruise mission range is conducted, analyzing the variation of each design variable within the optimization process. Moreover, a comparative study is implemented to illustrate the effects of the powertrain system on the eVTOL aircraft. Finally, a sensitivity analysis of the cruise mission range is presented. This paper addresses the gap in current eVTOL design methodologies from the powertrain perspective, further reducing the mission cost of eVTOL aircraft within the revenue mission profile.

The rapid growth of electric vehicle markets is producing large volumes of retired lithium-ion batteries retaining 70–80% of their original capacity, suitable for stationary energy storage. This study assesses the techno-economic and environmental viability of second-life battery energy storage systems (SLBESS) in a California commercial building, using one year of operational data. SLBESS performance is compared with equivalent new battery systems under identical dispatch strategies, building load profiles, and time-of-use tariff structures. A dispatch-aware framework integrates multi-year battery simulations, degradation modeling, electricity cost analysis, and life cycle assessment based on marginal grid emissions. The economic analysis quantifies the net present value (NPV), internal rate of return (IRR), and operational levelized cost of storage (LCOSop). Results show that SLBESS achieve 49.2% higher NPV, 41.9% higher IRR, and 13.8% lower LCOSop than new batteries, despite their lower round-trip efficiency. SLBESS reduce embodied emissions by 41% and achieve 8% lower carbon intensity than new batteries. Sensitivity analysis identifies that economic outcomes are driven primarily by financial parameters (incentives, acquisition cost) rather than technical factors (degradation, initial health), providing a clear rationale for policies that reduce upfront costs. Environmentally, grid emission factors are the dominant driver. Battery degradation rate and initial state of health have minimal impact, suggesting that technical concerns may be overstated. These findings provide actionable insights for deploying cost-effective, low-carbon storage in commercial buildings.

All-solid-state lithium batteries (ASSLBs) have emerged as promising next-generation energy storage systems, offering enhanced safety and higher energy density compared to conventional Li-ion batteries. However, their practical performance remains limited by interfacial instabilities. In this work, we systematically investigate the interfacial reactions and secondary phase formation between garnet-type cubic Li6.4La3Zr1.4Ta0.6O12 (LLZTO) and a variety of commercial cathode materials, including polycrystalline LiNi0.5Mn1.5O4 (pc-LNMO), LiCoO2 (pc-LCO), LiNi1-x-yMnxCoyO2 (pc-NMC811, 631, 532, 111), and single-crystalline NMC631 (sc-NMC631). Structural analyses reveal that interfacial phase evolution is highly dependent on cathode composition, crystal structure, and sintering temperature. Among all compositions studied, sc-NMC631 exhibits superior thermal compatibility with LLZTO, maintaining phase integrity up to 1000 degrees C. In contrast, polycrystalline cathodes undergo distinct interfacial degradation: La2Zr2O7 and LaCoO3 form at 700 degrees C in pc-LCO + LLZTO, while Li2MnO3 and La2Zr2O7 emerge as early as 400 degrees C in pc-LNMO + LLZTO. In pc-NMC + LLZTO composites, LaMO3-type (M: Ni, Mn, Co) phases are consistently observed. Additionally, La2(Ni0.5Li0.5)O4 phase is present in these Ni-rich compositions and Li2MnO3 is in the Ni-lean NMC111. Electrochemical studies reveal a 63% capacity loss in pc-NMC631 + LLZTO-900, primarily due to resistive interfacial phases and poor solid-solid contact that impede Li-ion transport. In comparison, sc-NMC631 + LLZTO-900 demonstrates a lower capacity loss of 48%, attributed to enhanced interfacial stability over its polycrystalline counterpart. However, the remaining capacity loss is likely due to misaligned Li-ion transport pathways across the rigid solid-solid interface. These results highlight the critical role of cathode selection and interface engineering in garnet-based ASSLBs and establish sc-NMC631 as a promising candidate for high-performance composite cathodes.

This paper proposes a conceptual design optimization method for the powertrain of electric vertical takeoff and landing (eVTOL) aircraft. The converter selection, semiconductor device selection, inductor design, capacitor selection, and thermal management design are discussed. The detailed analysis of various losses, including semiconductor losses, magnetic component losses, and auxiliary electronics losses, is illustrated. Moreover, the hybrid optimization algorithm is utilized to address the problem of multiple local optima. A configuration study with a 30km cruise mission range is implemented to analyze the variation of each design variable in the optimization. Additionally, a comparison study is conducted to assess the impact of powertrain system design on eVTOL aircraft. The proposed method achieves up to a 4.3% reduction in gross mass and an 8.8% reduction in required battery energy, highlighting the significance of incorporating powertrain modeling in aircraft-level optimization. Finally, sensitivity analysis is presented with respect to the mission range. This paper bridges the gap in current eVTOL design methodologies from a powertrain perspective, further reducing gross mass and providing guidelines for powertrain design in eVTOL aircraft.

Accurate State of Health (SOH) estimation is crucial for safe, efficient, and optimal operation of lithium-ion batteries (LIBs), yet it remains challenging in real-world applications. In this regard, this paper presents a novel approach to estimating the SOH of lithium-ion batteries using a convolutional neural network (CNN) model enhanced with 3D histogram feature extraction and transfer learning. Unlike traditional models, our method is uniquely capable of handling varying lengths of input time series data with the varying sliding window, making highly adaptable to real-world scenarios where data maybe irregular or incomplete. The integration of transfer learning further enhances the model's adaptability, allowing it to efficiently generalize across different battery types and operational conditions with minimal retraining. Experimental results demonstrate the model's accuracy and robustness, with significant improvements over existing methods in terms of estimation accuracy, computational efficiency, and adaptability to new data. This research offers a practical and scalable solution for battery health monitoring, supporting the advancement of reliable and efficient battery management systems.

Batteries play a critical role in achieving a sustainable energy future, enabling the integration of renewable energy sources and supporting electrified transportation and smart grids [...]

The electron ion collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing superconducting magnets (SC) from the RHIC storage ring. However, for some sectors of the machine, a modification of the accelerators optics will be required. To do this, the existing RHIC magnet electrical circuits will have to be modified and some superconducting current leads will need to be used at higher current. A work has been conducted to understand the current leads design parameters and their operational flexibility around these parameters, in particular for use at higher current. This paper details the study of the existing RHIC current leads, their potential for use at higher current and where required the modifications to extend their operational range.

This paper provides a comprehensive overview of recent advancements, challenges, and potential applications of wireless power transfer technology. It covers various aspects of wireless power transfer, including magnetic-filed coupling, electric-filed coupling, microwaves, and laser technologies. The paper sheds light on physical mechanisms, current state-of-the-art techniques, their limitations, and the prospects of this rapidly evolving field, with a focus on both theoretical developments and practical implementations. This review aims to contribute to the understanding and advancement of wireless power transfer systems for diverse applications in the modern technological landscape. This paper discusses not only the field of wireless power transmission that has already been applied, such as wireless charging of electric vehicles, consumer electronics, implantable medical devices, and underwater equipment, but also applications that are still under research such as space microwave transmission, large-scale free space energy transmission, and roadway-powered electric vehicles.

The ongoing transition toward electric vehicles is a major factor in the exponential rise in demand for lithium-ion batteries (LIBs). There is a significant effort to recycle battery materials to support the mining industry in ensuring enough raw materials and avoiding supply disruptions, so that there will be enough raw materials to produce LIBs. Nevertheless, LIBs that have reached the end of their useful lives and are sent for recycling may still have some energy left in them, which could be dangerous during handling and processing. Therefore, it is important to conduct discharge pretreatment of LIBs before dismantling and crushing them, especially in cases where pyrometallurgical recycling is not used. Electrochemical discharge in conducting solutions has been commonly studied and implemented for this purpose, but its effectiveness has yet to be fully validated. Non-electrochemical discharge has also been researched as a potentially cleaner and more efficient discharge technology at the same time. This article presents a non-electrochemical discharge process by completely draining the energy from used batteries before recycling. A comprehensive investigation of the behavior of LIBs during discharge and the amount of energy remaining after fully discharging the battery at different temperatures is analyzed in this work. According to the experimental findings, completely discharging the battery at higher temperatures results in a reduced amount of residual energy in the battery. This outcome holds great importance in terms of safe and environmentally friendly recycling of used LIBs, emphasizing that safety and environmentally friendly recycling must go hand in hand with a cost-effective and sustainable solution.

This paper proposes a single-phase, transformer-less, seven-level inverter that utilizes eight switches, three capacitors, and two diodes to produce seven voltage levels with triple boosting ability. The availability of the common-ground point eliminates the leakage current in PV applications. The proposed Transformer-Less Triple-Boosting Seven-Level Inverter (TLTB7LI) has the ability to feed different types of loads from non-unity to unity power factors. The voltage balancing of capacitors takes place naturally without the need for auxiliary circuits and complicated control strategies. This paper investigates the appropriateness of the proposed TLTB7LI for grid-connected application. The Peak Current Controller (PCC) is employed to generate the switching pulses and regulate the active/reactive power transfer between the converter and the output, which guarantees the high quality of injected current to the output. Moreover, the operational principles, its control technique, as well as the design procedure of the key components of the proposed inverter have been presented. The superiority of the proposed inverter over existing counterparts has been verified through comparative analysis. The simulation and experimental analysis validated the proper operation of the proposed TLTB7LI.

Aircraft conceptual design is a high-dimensional optimization problem, involving up to hundreds of continuous design variables and constraints. The design of novel aircraft concepts such as electric vertical takeoff and landing (eVTOL) vehicles can benefit from the systematic exploration of the design space through the use of gradient-based optimization. In this paper, we demonstrate the application of large-scale multidisciplinary design optimization (MDO) to NASA's lift-plus-cruise electric air taxi concept, using low and mid-fidelity physics-based simulations to model the aircraft. We improve the modeling fidelity from our previous work on the same air taxi concept through refined rotor-aerodynamic and aeroacoustic models as well as in-the-loop structural analysis. In addition, we expand the scope of the analysis to include several steady design conditions, a quasi-steady transition maneuver, structural sizing conditions, as well as one-engine-inoperative (OEI) scenarios, amounting to 18 design conditions. To perform the analysis and optimization, we use a newly developed software library called the Comprehensive Aircraft high-Dimensional Design Environment (CADDEE), which facilitates the integration of all discipline models. We solve a gross weight minimization problem with over 300 design variables and over 200 constraints, spanning all modeled disciplines. Results show a decrease in gross weight of 10% after a total optimization time of about 17 hours. These results demonstrate the effectiveness of applying of large-scale MDO to the aircraft conceptual design problem.

In the conventional design of a double-sided LCL compensation network for the capacitive power transfer (CPT) system, two external capacitors are connected in parallel with the horizontal capacitive coupler, or a vertical capacitive coupler is required to reduce the resonant inductances. This approach results in a loosely coupled structure. The compensation inductor resonates with the whole coupler, inducing reactive power transferred from the primary to the secondary side, leading to higher voltage stresses on the plates, which inevitably increases the system complexity and susceptibility to air breakdown. This paper proposes a double-sided LCL compensation network design method for the CPT system where no parallel-connected capacitors are required, thereby a strongly coupled structure can be obtained with a constant current (CC) output and input zero phase angle (ZPA) characteristics. By keeping the phase angle difference between the voltage vectors across the primary and secondary plates at 90°, no reactive power is transmitted from the primary to the secondary side. Thus, the voltage stresses across the plates can be minimized. A 500W prototype with a high coupling coefficient of 0.82 is established to verify the proposed system and an efficiency of 90% is achieved.

Interest in electric aircraft has increased due to developments in electric propulsion technology and concerns regarding aircraft carbon emissions. The emerging urban air mobility industry aims to provide convenient short-range air travel using electric aircraft. An important factor in the design of electric aircraft is the modeling and design of electric motors. The many degrees of freedom in electric motor design make it a complex design problem. To mitigate this complexity, we have developed an adjoint-based electric motor design methodology using free-form deformation for geometry parameterization, PDE-based mesh warping with exact derivatives for mesh manipulation, and finite element analysis for electromagnetic modeling. This paper highlights the approach and details of the proposed method and presents results from its application to a representative motor design problem. The optimization results in a 35