Journal of Power Sources Advances最新文献

The novel trajectory correction hysteresis model (TCH) is based on measuring the first-order reversal branches (FORBs). As the enormous measurement effort required for parameterisation hinders a real-world application, this paper presents the data-efficient transfer fit (TF) method. The TF methodology is validated through two application cases: ageing update and cell chemistry adaptation. Remarkably, using only 12 measurement points on the open-circuit voltage (OCV) envelopes instead of hundreds of measurement data points, the ageing update TF model attains a mean absolute error (mae) of 4.1 mV, closely approaching the accuracy of a newly parameterised target model (3.6 mV mae). Similarly, adapting an NCA cell model to an NMC target cell using selected OCV envelope points yields a 5.3 mV mae, which further reduces to 3.2 mV with an additional discharge FORB starting at 10% SOC. In addition to the selective model adjustment using continuous OCV measurement trajectories, the much more realistic adaptation by measurement points randomly distributed within the hysteresis window was successfully demonstrated. The presented TF methodology overcomes the hurdle of data efficiency while maintaining model accuracy and paves the way for the future application of the TCH model for voltage-based SOC correction.

This study analyzes the field performance of various solar cell designs. Most research and development efforts concerning solar cells aim to increase their efficiency or power under standard test conditions (STC). However, conducting an actual field performance analysis is crucial because of the various ambient conditions present in the field, including temperature, irradiance, PV system installation, and albedo. These conditions can result in different performance results compared to STC. This study compares and analyzes case studies to assess field performance. One particular case study compares the field performance of monofacial modules with a monofacial passivated emitter and rear cell (PERC) and bifacial PERC at a carport system in the ambient conditions of the Korean Peninsula during summer and winter. The module material properties (white EVA and white backsheet) can impact module performance owing to the transmittance spectra at longer wavelengths. Certain transmittance values also contribute to the bifaciality number. Although the monofacial cell demonstrates better STC results, the field performance of the bifacial cell is superior in terms of energy yield and cost-effectiveness. Therefore, this study highlights the importance of considering the field performance (energy yield), in addition to STC, when designing solar cells and modules.

Crystal orientation plays a crucial role in the performance of Sb₂S₃ thin-film solar cells (TFSCs). Among various deposition techniques, vapor transport deposition (VTD) stands out as a viable technique for producing scalable and uniformly deposited thin films, particularly in the solar industry. This study explores temperature-modulated VTD-Sb₂S₃ deposition to enable efficient carrier transport in photovoltaic cells. In the VTD process, the deposition temperature is altered between 480 °C and 540 °C. XRD, SEM, EDS, and AFM techniques are employed to obtain the characteristics of the Sb₂S₃ thin films at varying temperatures and evaluate critical features like crystal structure and orientation, surface morphology, composition, and roughness. The prominent crystal orientation changes from the (hk0) to the (hk1) plane after increasing the deposition temperature from 500 to 520 °C. The (211)- and (221)-planes become more prominent when the deposition temperature exceeds 520 °C. The device with the architecture SLG/Mo/Sb₂S₃/CdS/i-ZnO/AZO/Al, a substrate-configured TFSC, yields a maximum power conversion efficiency of 0.22% when the VTD-Sb₂S₃ absorber film is deposited at 520 °C. This study presents a promising approach to producing thin films with a preference for specific crystal orientations. The primary aim is to enhance the efficiency of solar cells that utilize VTD-Sb₂S₃ absorbers.

Sodium vanadium triphosphate (Na₃V₂(PO₄)₃, NVP) is a promising cathode material for Na-ion batteries. Due to its intrinsically low electronic conductivity, it is usually mixed or coated with carbon. However, so far there have been no systematic studies on the ionic and electronic conductivity of carbon-coated NVP particles. In this work, NVP with varying carbon contents are prepared. The powders are sintered as single pellets or sandwiched between a solid electrolyte for measurements in an ion blocking and non-ion blocking configuration. In these two different configurations, two different electrodes are attached and several electrochemical characterization techniques are applied such as impedance spectroscopy, chronoamperometry, and four-point measurements. The NVP/C composites with carbon content >0.1 wt% show a high degree of densification and an amorphous carbon network. The conductivity of NVP in composites with carbon content <0.1 wt% shows dominating ionic conduction with an average value of ∼2 × 10⁻⁶ S cm⁻¹. NVP/C samples with carbon contents >0.1 wt% show a dominance of electronic conduction in the range of 0.01–0.2 mS cm⁻¹ because of the percolated carbon network at the grain boundaries. The ionic conductivity, however, remains almost constant in the same order of magnitude (∼6 × 10⁻⁶ S cm⁻¹).

The dynamic behavior of potentials and currents in porous electrodes is crucial for optimizing the computational speed of lithium-ion battery models. Pseudo-two-dimensional (P2D) models, based on partial differential equations, offer insight but pose computational challenges. P2D equations are tackled with iterative algorithms, like the Newton or the shooting method. Yet, initiating the algorithm with random guesses for solid and electrolyte potentials can cause diverging ionic current values inside the electrolyte phase, increasing the computation time required to converge to the final solution. This study proposes a novel model order reduction using a galvanic pseudo-potential to prevent the occurrence of diverging currents. By sidestepping infinite values for ionic current inside the electrolyte phase, the method streamlines math and speeds up the shooting method used for solving battery model equations.

Lithium-metal anodes are promising electrodes for fabricating high-capacity all-solid-state batteries; however, lithium dendrite growth during charging limits their applicability. One method to suppress lithium dendrite growth is to insert a carbon interlayer between the solid electrolyte and the lithium-metal anode. There are many potential approaches for inserting a carbon interlayer. The optimal conditions for suppressing lithium dendrite growth and ensuring uniform lithium deposition have not yet been established. This study employs X-ray computed tomography to investigate anode-less all-solid-state batteries. Pressurized xenon is used to examine how the carbon interlayer functions and how uniformly lithium is deposited after various carbon interlayer insertion processes. Uniform deposition is observed following simultaneous pressure bonding of the carbon interlayer and compression of the solid electrolyte.

Finding a correlation between the rheology of an electrode slurry and the mixing variables is challenging due to the complex interactions among the materials in the suspension. Here, we report a systematic study of the mixing speed and how this variable impacts the slurry rheology of the Nickel Manganese Cobalt Oxide (NMC622) positive electrode at 2000, 3000, and 4000 rpm and maintaining constant the other mixing parameters. We partially combined the slurry components and compared the rheology results with the complete formulation. This systematic study shows differences in viscosity depending on mixing speed and the slurry component combination. In addition, frequency oscillatory sweeps were used to obtain information on the slurry microstructure, showing changes depending on the nature of component interactions. The slurries were also casted, dried, and calendered. Numerical simulations were also performed to analyze the experimental findings. Understanding the slurry rheology and the interaction of the formulation components is fundamental for further engineering electrode manufacturing and analysis of the dried electrode's output properties.

The need for high-energy and safe batteries is more and more urgent, and a possible approach is to use solid polymer electrolyte with high conductivity combined with lithium metal anode. Poly (1,3-dioxolane)-based electrolytes are promising, and the feasibility to polymerize 1,3-dioxolane (DOL) in situ makes this approach very attractive. In this paper, we present the in situ electro-initiated polymerization of DOL in polyacrylonitrile nanofibrous mats, without using initiator or crosslinking agents. The amount of monomer loaded in the porous scaffold, the electrochemical technique used to initiate the polymerization and the salt amount were investigated as important parameters that affect the ion conductivity and the performance of the obtained polymer electrolyte. Particular attention was directed towards minimizing the presence of residual monomer in the resulting polymer, with the aim of progressing towards the development of a real solid-state polymer electrolyte. The results of the thermal, morphological, and electrochemical characterization are reported and discussed.

Lithium-ion batteries with silicon-graphite composite anodes feature an asymmetric and direction-dependent voltage hysteresis. Upon comparing established hysteresis models from literature, it was found that a separate modelling of charge and discharge direction is required for both the operator-based Preisach model and the differential equation-based one-state model, often referred to as Plett model. This paper presents the first bidirectional implementation of the one-state hysteresis model based on extensive measurements of first-order reversal branches of a Si/C NMC cell. The approach accounts for directionality but cannot deal with the complexity of the hysteresis traverses, so an extension of the Preisach model is discussed and found to be infeasible. This justifies the development of a novel hysteresis model, the trajectory correction hysteresis (TCH) model, that fulfils the identified requirements for bidirectionality, closed-loop property and direct data fit and can be generally applied to any cell chemistry. The TCH model considers the traverse starting point, which allows for the unambiguous definition of hysteresis states and enables the simulation of complex trajectories due to two correction mechanisms. The static and dynamic current profiles in complex hysteresis scenarios demonstrate superior performance with 4.5 mV mae compared to Preisach (19.6 mV mae) and Plett (11.7 mV mae) models.

Li-ion batteries (LIBs), thanks to high efficiencies and energy density, represent the mainstream technology to replace traditional internal combustion vehicles with electric ones. However, LIBs state of health (SoH) should be investigated to avoid fast degradation due to fast-charging, electrical, mechanical and thermal factors. Therefore, SoH prediction and monitoring for battery electric vehicles is necessary for extending LIB lifespan and avoiding failures. In this paper, an accurate real-time SoH prediction and monitoring method, based on discrete wavelet (DWT) analysis, is investigated through an extensive experimental campaign considering the effect of temperature variation. Specifically, moving from cycle aging performed on Li-ion NCR 18650 cells and applying two typical US test drive cycles at different SoHs, three different operating temperatures (i.e., 0 °C, 20 °C and 30 °C) were investigated. Applying DWT on the gathered LIB voltage profiles, it is demonstrated that temperature effect on the implemented method is easily recognizable from the one of cycle aging. Moreover, suitable linearized functions are identified to refer DWT outcomes assessed at the operative temperature to a reference temperature, at which a suitable equation is previously identified to assess capacity fading. Due to its general validity the method can be extended to stationary applications.