Cylindrical Cell Research Articles

Electrochemical Reclamation of Lithium-Ion Battery Materials Using SPOT Recycling

Establishing clean, low-cost methods for recycling lithium-ion batteries is essential for securing a sustainable supply chain for our green energy future. Cool Amps has developed a proprietary electrochemical process for lithium-ion battery recycling that avoids costly and environmentally unsound processing steps such as shredding and pyrometallurgy. Cool Amps uses our prototype laminar flow extraction modules to harvest valuable materials from production scrap or end-of-life batteries with a variety of form factors (cylindrical, pouch, and prismatic cells). The small footprint of our extraction modules allows us to be co-located at gigafactories or end-of-life collection facilities for SPOT recycling, negating the need for complex shipping and transportation logistics and significantly reducing recycling costs. In lab-scale demonstrations, our process recovers >85% of the valuable transition metals harvested from cathode materials and leaves the anode graphite intact and ready for re-use. These materials are characterized by elemental analysis, powder x-ray diffraction, and scanning electron microscopy. We will demonstrate that the reclaimed components are viable components for manufacturing recycled lithium-ion batteries, enabling a secure and circular supply chain for America’s green energy future.

Diagnosing NMC Battery Aging Modes Using Digital Twin

Traditional lithium-ion battery (LiB) modeling does not provide sufficient information to accurately verify battery performance under real-time dynamic operating conditions, particularly when considering various aging modes and mechanisms. This paper proposes a lithium-ion battery digital twin that can capture real-time data and integrate the strong coupling between SEI layer growth, anode crack propagation, drying up of Electrolytes, and lithium plating. It can be utilized to predict the degradation behavior, voltage-current profiles in dynamic aging conditions, and analyze the lithium inventory loss (LLI) of Nickel-Manganese-Cobalt-Oxide (NMC) lithium-ion batteries.Commercially available 18650 cylindrical NMC Samsung battery cells were investigated. The cathode and anode materials are LiNi0.5Co0.2Mn0.3O2 and synthetic graphite, respectively. Four dynamic aging test cases using 1C, 1.3C, MC (multistep charging), and 2C, were designed and performed at 25 °C. The reference performance test (RPT) was repeated every 100 full equivalent cycles (FECs) until the cells reached 20 % capacity fade. Figure 1 shows the real-time voltage and current profile captured and predicted by the digital twin.The model takes into account LLI induced by SEI growth and lithium plating, aligning with the LLI calibrated from the differential voltage (DV) endpoint shift (Figure 1h). Based on the model results, SEI growth is found to be the primary contributor to capacity loss before 500 FECs. SEI-induced degradation is minimal under the MC protocol, with the capacity loss varying by less than 5.22% across four test cases (Figure 1e). After 500 FECs, anode cracking becomes a non-linear accelerated aging factor. The crack propagation stabilizes in the initial 200 FECs, followed by unstable accelerated growth leading to capacity loss. Subsequently, a rapid acceleration in capacity loss occurs after 700 FECs (Figure 1f). The growth of anode cracks under the MC aging protocol has a much slower effect on capacity loss compared to the 2C and 1.3C before 500 FECs, as strongly confirmed by the post-mortem analysis. In addition, the lithium plating phenomenon triggers two orders of magnitude less capacity loss than SEI growth and cracking at 25 °C. The MC protocol demonstrates an effective reduction in lithium plating capacity loss compared to the other three traditional charging protocols (Figure 1g). This digital twin can represent a firm physical foundation for future physics-informed machine learning development to predict LiBs degradation behavior.Figure 1. Real-time voltage and current captured and predicted by our designed digital twin under (a) 1C-WLTC, (b)1.3C-WLTC, (c) MC-WLTC, and (d) 2C-WLTC aging profiles. Additionally, (f) illustrates capacity loss density for the four protocols attributed to (e) SEI film growth, (f) anode crack propagation, (g) Li plating, and (h) LLI prediction by the digital twin and DV measurement. Figure 1

(Digital Presentation) Innovative Cylindrical Cell Design for Sustainable Static Zinc-Bromine Battery Technology

Zinc-bromine flow batteries (ZBFBs) are suitable for large-scale stationary energy storage applications due to their scalability, flexibility, safety, and sustainability [1, 2]. However, the ZBFBs' efficiency is compromised by the heavy accessories and pumps involved in flowing electrolytes on the electrode surface [3]. Because of their heavy weight and other accessories, ZBFBs can only be used for large energy storage systems. Further research is required to expand the application fields of the small-scale static zinc-bromine battery, including portable applications. Therefore, we proposed an innovative cylindrical cell design for a static zinc-bromine battery with a non-flowing liquid electrolyte that offers substantial improvements over existing zinc-bromine flow battery technology. This design aims to enhance coulombic efficiency and energy density, particularly targeting portable applications such as electric vehicles and E-bikes. Our battery configuration involves electrodes (carbon felt and carbon sponge) separated by a microporous separator for ionic migration. The liquid electrolyte, comprising zinc bromide, zinc chloride, potassium chloride, and 1-ethyl-1-methyl pyrrolidinium bromide, facilitates the electrochemical reaction. The battery's electrochemical process involves the plating of zinc ions at the anode and the formation of a bromine complex at the cathode during charging, with reverse reactions during discharge. The entire proposed static battery configuration is made of recyclable Polytetrafluoroethylene (PTFE) polymer, ensuring environmental sustainability. The anode comprises highly conductive graphene-coated carbon felt, while the cathode employs a graphene-coated high-surface-area carbon fiber sponge. Here, we aim to provide more details on the manufacturing methods for the assembly, emphasizing slurry preparation, electrode modification, and electrolyte concentration to achieve enhanced battery performance. With 96 % coulombic efficiency and stable cyclability, the present technology outperforms the existing commercial zinc-bromine battery. Comparative analyses with conventional zinc-bromine flow batteries highlight the advantages of this static battery, including its compactness, reduced weight, and potential for higher energy density. This research represents a significant step towards developing static zinc-bromine batteries suitable for widespread use in portable applications, surpassing the limitations of current zinc-bromine battery technologies.

High-Frequency Electrochemical Impedance Spectroscopy for Detecting Li Deposition Toward Assessing Thermal Stability in LiBs

Li-deposition is a critical factor in one of the degradation modes of lithium-ion batteries (LiB). The Li-deposition increases the risk of internal short circuits and lowers thermal runaway onset temperature, compromising safety1. Detecting the Li-deposition is possible through disassembly or analysis using large-scale equipment such as muonic X-ray visualization 2. On the other hand, a non-destructive and convenient evaluation technique is required to assess batteries’ safety in commercial use.A novel inspection technique using high-frequency electrochemical impedance spectroscopy (HF-IS) has been developed to detect the presence of Li-deposition3. Electrochemical impedance spectroscopy (EIS), which nondestructively observes ionic diffusion, reaction, and charge transfer in 10 mHz to 10 kHz response, is commonly used for diagnosing the state of battery degradation4. Compared to the conventional EIS, the HF-EIS uses the real part of battery impedance Re(Zbat ) above 100 kHz, allowing observation of only the electronic behavior of the battery in high-frequency regions where ion behavior cannot be tracked. It utilizes the phenomenon of current concentration at interfaces of materials with different conductivities, known as the "skin effect," which is caused by a high-frequency electromagnetic field. Since the Li-deposition occurs at the interface between the negative electrode and the electrolyte, the interface within the high-frequency current path changes from the negative electrode to the Li-metal. This change induces alterations in the electromagnetic field and the high-frequency current path, subsequently resulting in a variation in Re(Zbat ).Figure 1 displays a representative result illustrating the relationship between the thermal runaway onset temperature and the change in Re(Zbat )| freq =1MHz. We conducted a degradation test to deposit Li-metal and a thermal runaway test using two types of 18650 cylindrical cells (NCA-3400 mAh, NCM-2650 mAh). Two batteries subjected to excessive charging C-rates demonstrated the proportional relationship between the decrease in thermal runaway onset temperature and the reduction in Re(Z bat)| freq =1MHz in individual cases. The results indicate that different battery types have different thermal stability of LiB against the Li-deposition.The HF-EIS is not only a safety diagnostic tool but can also contribute to developing battery materials by reducing destructive testing costs. This method of on-the-spot safety quantification diagnosis is expected to contribute to the safer proliferation of the LiBs.Reference1 Li, Y. L. et al. Thermal Runaway Triggered by Plated Lithium on the Anode after Fast Charging. Acs Applied Materials & Interfaces 11, 46839-46850 (2019). https://doi.org/10.1021/acsami.9b165892 Umegaki, I. et al. Nondestructive High-Sensitivity Detections of Metallic Lithium Deposited on a Battery Anode Using Muonic X-rays. Analytical Chemistry 92, 8194-8200 (2020). https://doi.org/10.1021/acs.analchem.0c003703 Ishigaki, M. et al. Operando Li metal plating diagnostics via MHz band electromagnetics. Nature Communications 14, 7275 (2023). https://doi.org/10.1038/s41467-023-43138-w4 Barsoukov, E. Impedance Spectroscopy Theory, Experiment, and Applications Second Edition Preface. Impedance Spectroscopy: Theory, Experiment, and Applications, 2nd Edition, XII-+ (2005). Figure 1

(Invited) Lyten’s High Energy Li-S Batteries for a Sustainable and Circular EV Economy

Li-ion batteries (LIB), though widely used in EV batteries will be unable to meet the demands of the rapidly expanding vehicular market, mainly due to the challenges of cost and availability of key materials globally with limited resources, complicated by geopolitical factors. Li-S batteries promise significant advantages over Li-ion batteries with potentially higher specific energy, lower cost, and enhanced safety. However, their implementation has been hampered by poor cycle life due mainly to polysulfide shuttle caused by the soluble polysulfide intermediates. Lyten, an advanced materials company, has developed a family of new 3D Graphene™ materials for various applications including lithium-sulfur batteries. The mechanically flexible and electrically conductive framework of 3D graphene and its hierarchical porous structure make it an ideal host for potentially confining sulfur intermediates and mitigate the polysulfide shuttle. Lyten 3D Graphene™ materials have already shown enhanced sulfur utilization in Li-S cells far superior to the commercial nanocarbons (Fig. 1), even while their further fine-tuning is on-going. Lyten has established environmentally friendly 3D graphene-sulfur cathode fabrication methodology with high sulfur loadings using an aqueous binder.In parallel, Lyten has been developing new protected Li anodes, advanced stable electrolytes that can function at low quantities (electrolyte/sulfur ratio), and multi-functional separators with an ability to block polysulfide crossover. Integration of these cell components resulted in Li-S cells with specific energy comparable to current Li-ion cells (250-275 Wh/kg). The cycle life is, however, relatively modest with 300 cycles @ 100% DOD, C/3 in coin cells, and ~150 cycles@100% DOD and over one thousand cycles @ 50% DOD in multi-layer pouch cells and 18650 cylindrical cells. There is a steady growth in both these categories enabled by further tuning of 3D graphene and advances in other materials.Recently, Lyten has set up semi-automatic assembly lines for both multi-layer pouch and 18650 cylindrical cells, targeting an annual capacity of 2.4 MWh. These cells have started showing excellent consistency in specific energy in both cell formats. Fig.2 shows the narrow variability in the performance of 35 pouch and 18650 cells made recently for a customer.Finally, preliminary safety tests performed on the recent prototype cells have yielded surprisingly good results for the Li-S cells containing Li metal anode. Tolerance to usual abuse conditions, e.g., internal and external shorts, overcharge and overdischarge, as demonstrated in our ARC tests will be an additive advantage of Lyten Li-S cells. Figure 1

Re-Functionalization of Aged Lithium Iron Phosphate Cathode Materials

As lithium-ion batteries continue to be implemented in everyday technologies, it is imperative to repurpose these battery materials upon their degradation. Carbon-coated lithium iron phosphate (LFP/C) is considered one of the most stable cathode materials for application in lithium-ion batteries. Due to this stability, LFP/C possesses a remarkably long cycle life of greater than 3000 cycles.1 Extended cycling of these cathode materials may result in multiple modes of degradation, including degradation of the carbon coating, and loss of contact between the cathode and the current collector.2,3 In this work, a suitable process and reagents have been selected to isolate and purify the LFP/C from the cathodes of cycled batteries. Isolating and purifying aged LFP/C materials enables the diagnosis of the mode(s) of degradation of these materials and their coatings using a variety of techniques including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy methods.Furthermore, additional work was pursued to give new life to these isolated, spent cathode materials. The addition of a coating with a relatively high lithium conductivity to the aged LFP/C particles was sought to provide a second life to these electrochemically aged materials. Half-cells were fabricated using the coated, aged LFP/C cathode materials to compare their performance to both pristine LFP/C nanoparticles and aged LFP/C nanoparticles without the addition of this custom coating. Electrochemical testing techniques such as galvanostatic cycling, cyclic voltammetry, and electrochemical impendence spectroscopy were used to probe the performance of each type of LFP/C nanoparticle as cathode materials in lithium-ion batteries. The coated, aged LFP/C particles were also characterized using transmission electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy techniques. The techniques developed herein can be used to isolate, purify, and re-functionalize other cathode materials from lithium-ion batteries. Lewerenz, M.; Munnix, J.; Schmalstieg, J.; Kabitz, S.; Knips, M.; Sauer, D. U. Systematic aging of commercial LiFePO4|Graphite cylindrical cells including a theory explaining rise of capacity during aging. Power Sources. 2017, 345, 254-263.Wang, L.; Qiu, J.; Wang, X.; Chen, L.; Cao, G.; Wang, J.; Zhang, H.; He, X. Insights for understanding multiscale degradation of LiFePO4 cathodes. eScience 2022, 2(2), 125-137.

Magnetodielectric and Rheological Effects in Magnetorheological Suspensions Based on Lard, Gelatin and Carbonyl Iron Microparticles.

This study aims to develop low-cost, eco-friendly, and circular economy-compliant composite materials by creating three types of magnetorheological suspensions (MRSs) utilizing lard, carbonyl iron (CI) microparticles, and varying quantities of gelatin particles (GP). These MRSs serve as dielectric materials in cylindrical cells used to fabricate electric capacitors. The equivalent electrical capacitance (C) of these capacitors is measured under different magnetic flux densities (B≤160 mT) superimposed on a medium-frequency electric field (f = 1 kHz) over a period of 120 s. The results indicate that at high values of B, increasing the GP content to 20 vol.% decreases the capacitance C up to about one order of magnitude compared to MRS without GP. From the measured data, the average values of capacitance Cm are derived, enabling the calculation of relative dielectric permittivities (ϵr') and the dynamic viscosities (η) of the MRSs. It is demonstrated that ϵr' and η can be adjusted by modifying the MRS composition and fine-tuned through the magnetic flux density B. A theoretical model based on the theory of dipolar approximations is used to show that ϵr', η, and the magnetodielectric effect can be coarsely adjusted through the composition of MRSs and finely adjusted through the values B of the magnetic flux density. The ability to fine-tune these properties highlights the versatility of these materials, making them suitable for applications in various industries, including electronics, automotive, and aerospace.

Analytical study on highway thermal runaway propagation and inter-electrode dynamics in lithium-ion battery applications: Insights into battery safety

It is essential to ensure thermal safety in lithium-ion (Li-ion) batteries to facilitate their increased use in electric cars, thereby enhancing the safety of individual batteries. When high-power Li-ion batteries are subjected to abusive conditions, they frequently experience thermal runaway (TR) due to a sequence of exothermic reactions resulting from electrode contacts. These events generate a significant amount of heat and have the potential to cause thermal runaway propagation (TRP) throughout the battery module. This paper presents an in-depth TRP analysis approach, combining thermo-kinetic and electrode interaction assessments at the cell level. The method is implemented on the TR properties of a cylindrical Li-ion cell equipped with nickel-rich and silicon-carbon electrodes. The developed TRP approach, incorporating various heat dissipation techniques, is applied to a prototype high-energy Li-ion chamber to evaluate TRP susceptibility under different conditions, including ambient temperature, cell spacing, initiating cell location, external heating power, and heat dissipation rates. Additionally, this research provides insights into the various TRP pathways, focusing on aspects such as the propagation rate, the exothermic processes’ thermal, required thermal energy input, and external heat release. The comprehensive model, considering both heat transfer and chemical interactions between electrodes under TR, can address accurate TR- propagation examinations for batteries. Moreover, it can be expanded to larger battery systems, ultimately improving overall battery safety.

A device for real-time detection of gas generated from commercial lithium-ion cell

Abstract Lithium-ion batteries generate a large amount of flammable and toxic gases under abuse conditions. Research on the detection methods of gas generation from batteries is of great significance for understanding the reaction mechanism of batteries under abuse conditions, assessing the impact of gas generation on the health of occupants, and developing safer battery products. However, there is a lack of research reports on the real-time gas production behavior of commercial batteries. In this paper, a device for real-time detecting the gas component of the cylindrical lithium-ion cell is designed. Combined with a gas mass spectrometer can implement the real-time detection of the gas component of the lithium-ion cell. The device is used to explore the gas generation characteristics of lithium-ion cells in the overcharged state, and the influence of the material system and the degree of aging on the results are analyzed, verifying the feasibility of the device.

Coupled Electrochemical-Thermal Runaway Model of Lithium-Ion Cells Operating Under High Ambient Temperatures

The risk of thermal runaway (TR) in high energy density Lithium-ion batteries (LIBs), which may initiate at around 90 °C, is a critical safety concern, particularly in regions where summer temperatures can reach nearly 50 °C. While multiple exothermic reactions that cause TR and modeled using Arrhenius equations lead to good predictions in controlled oven tests, their use in practical applications is questionable as these do not consider internal electrochemical processes that cause temperature rise and trigger exothermic reactions. Further, limited literature focuses on coupling electrochemical thermal models with exothermic reactions. This study demonstrates a method to couple the electrochemical and thermal runaway models for a commercial cylindrical Lithium-ion cell. The proposed model averages pseudo-2D electrochemical heat and couples it to a two-dimensional, axisymmetric heat transfer model of 18650-type Lithium-ion cell. The jellyroll structure is approximated as a homogeneous and anisotropic domain for electrochemical and exothermic heating. Simulations are performed through several, uninterrupted charge-discharge cycles at different ambient temperatures and C-rates. We show that while cycling rate is critical in instigating and accelerating TR, parameters like ambient temperature, particle radii and initial electrolyte concentration also play a role in determining the core temperature and its rate of growth in the cell.

Corrosion of Lithium-ion Battery Cylindrical Cell Hardware: Understanding the Mechanisms and Exploring Effective Solutions

We present a detailed examination of Ni corrosion in lithium-ion battery Ni-coated steel cylindrical cell hardware, focusing on LiPF6-based electrolytes contaminated with water. The corrosion potential of the cell hardware is predominantly controlled by the iron component of the cylindrical can which cathodically protects the Ni coating. Despite the presence of cathodic protection, the Ni coating still experiences significant crevice corrosion, as confirmed through chemical aging tests. Mechanistic investigations on pure Ni metal reveal two distinct corrosion pathways depending on the presence or absence of oxygen in the electrolyte. The pathway involving oxygen proves to be more detrimental, as it oxidizes Ni in conjunction with acid, leading to the generation of water and the regeneration of corrosive species. This pathway exhibits corrosion rates two orders of magnitude higher than the alternative pathway. The dissolved Ni species predominantly exist in the +2 oxidation state and forms highly soluble F-rich compounds, comprising a mixture of associated species denoted by the formula Ni(PxOyFz)w. Finally, several suggestions for effectively mitigating Ni corrosion have been proposed, with alloying with chromium being the most effective.

Gas evolution analyses of Ni-rich Li-ion and Li-metal batteries at cylindrical jelly-roll configurations

Understanding gas evolution during battery operation is pivotal for elucidating the underlying mechanisms of battery behavior, a cornerstone for fostering innovation in energy storage technologies. Despite the wealth of quantitative analyses available, the realm of large-scale, practical, full-cell investigations remains relatively unexplored. This study bridges this gap by unveiling a novel, robust gas chromatography methodology designed to meticulously quantify gas generation within 18650 cylindrical cells Li-ion and anode-free Li-metal Ni-rich batteries across a spectrum of operational conditions. Our approach not only reaffirms the capability for precise, reliable quantitative measurements but also illuminates new findings on the dynamics of gas evolution. This includes the significant impact of temperature and cathode material composition on gas generation, alongside a pioneering exploration into the behavior of anode-free Li-metal batteries. These insights not only advance our understanding of battery performance and safety at a practical cell level but also pave the way for the development of more efficient, durable, and safer energy storage solutions.

Thermal convection of a liquid metal under an alternating magnetic field

The objective of this work is to measure the heat transfer of a liquid metal in a cylindrical cell under the conjugate effects of a temperature difference and a Lorentz force generated by an alternating current in a coil. The experimental results are compared to recent direct numerical simulations (DNS) (Guillou et al., 2022). 25 experiments are performed for a large range of frequency f, ac intensity amplitude I0 and temperature difference between the top and bottom walls ΔT0: 15≤f≤1000Hz, 2≤I0≤67 A and 6≤ΔT0≤11 K. In these experiments, the Hartmann number Ha, the shielding parameter Sω and Rayleigh number Ra vary in the following range: 6≤Ha≤200, 1≤Sω≤70, 2.3×106≤Ra≤4.1×106. The experiments with an ac magnetic field are compared with the Rayleigh–Bénard convection (RBC) experiments under the same thermal conditions. Three rings of thermocouples allow characterizing the fluid temperature distribution during the convection. The heat flux at the bottom and top walls are also measured. We observe a very good agreement between the experimental results and the DNS results. As previously shown by numerical simulations, a master curve of Nu/Peω vs. QJ/Qc allows predicting the evolution of the heat transfer under different conditions of temperature difference and Lorentz force. Here Nu and Peω are the Nusselt number and a Péclet number based on the Lorentz force, and QJ and Qc are the total power deposited by the Joule effect and the total conduction heat flux without motion, respectively. The experiments show that Nu/Peω∼(QJ/Qc)−2/5.

Optimal Fast-Charging Strategy for Cylindrical Li-Ion Cells at Different Temperatures

Ensuring efficiency and safety is critical when developing charging strategies for lithium-ion batteries. This paper introduces a novel method to optimize fast charging for cylindrical Li-ion NMC 3Ah cells, enhancing both their charging efficiency and thermal safety. Using Model Predictive Control (MPC), this study presents a cost function that estimates the thermal safety boundary of Li-ion batteries, emphasizing the relationship between the temperature gradient and the state of charge (SoC) at different temperatures. The charging control framework combines an equivalent circuit model (ECM) with minimal electro-thermal equations to estimate battery state and temperature. Optimization results indicate that at ambient temperatures, the optimal charging allows the cell’s temperature to self-regulate within a safe operating range, requiring only one additional minute to reach 80% SoC compared to a typical fast-charging protocol (high current profile). Validation through numerical simulations and real experimental data from an NMC 3Ah cylindrical cell demonstrates that the simple approach adheres to the battery’s electrical and thermal limitations during the charging process.

Propensity of 21700 cylindrical cells to thermal runaway under slight overcharging cycling – A numerical study

Slight overcharge of lithium-ion batteries (LIBs) could occur due to inadequate design of battery management system or unexpected malfunction of charger. In comparison with other abuse conditions, the evolution of thermal runaway (TR) under slight overcharging often requires a lengthy incubation period, necessitating relatively long periods for experiments. Numerical simulations with validated models offer a viable alternative to evaluate such risks in modules/packs and associated mitigation measures. Since a current-cutting device is usually installed inside the LIB module/packs, the current will be cut off once the overcharge reaches a certain level, therefore, slight overcharging is of more potential relevance. However, previous simulations mainly focused on TR process induced by continuous overcharging, the conditions associated with slight overcharging have been overlooked. As slight overcharging is difficult to detect, the generated heat could easily accumulate as the cycle process prevails, result in unwanted cell temperature increases with increasing propensity for TR. A three-dimensional (3-D) predictive tool for the transition of cylindrical 21700 cell from slight overcharging cycle to TR has been developed by implementing the published models for heat generation from various thermal decomposition reactions and ISC into in-house version of the opensource computational fluid dynamics (CFD) code OpenFOAM. The code is validated with newly conducted experiments involving both normal and slight overcharging cycles. The validated model has then been used to conduct further parametric studies to investigate the effects of the overcharge voltage, current-rates and convective cooling on the propensity and run up time to TR as well as the maximum cell temperature during TR for cells with different cathode materials under different ambient temperatures. This work forms a sound basis for evaluating TR propagation in modules/packs under slight overcharging/discharging cycles to aid the development of mitigative measures to improve LIB process safety in practical applications.

Characterization of Fusarium solani Associated with Tobacco (Nicotiana tabacum) Root Rot in Henan, China.

The aim of this study was to characterize the Fusarium solani species complex (FSSC) population obtained from tobacco roots with root rot symptoms by morphological characteristics, molecular tests, and assessment of pathogenicity. Cultures isolated from roots were white to cream with sparse mycelium on potato dextrose agar, with colony growth of 21.5 ± 0.5 to 29.5 ± 0.5 mm after 3 days. Sporodochia were cream on carnation leaf agar (CLA) and Spezieller Nährstoffarmer agar (SNA), and macroconidia formed in sporodochia were 3 to 6 septate and straight to slightly curved, with wide central cells, a slightly short blunt apical cell, and a straight to almost cylindrical basal cell with a distinct foot shape, ranging in size from 20.92 to 64.37 × 3.91 to 6.57 μm. Microconidia formed on CLA were reniform and fusiform, with 0 or 1 to occasionally 2 septa, that formed on long monophialidic conidiogenous cells, with a size range of 5.99 to 32.32 × 1.76 to 5.84 μm. Globose to oval chlamydospores were smooth- to rough-walled, 6.5 to 13.3 ± 0.37 μm in diameter, and terminal or intercalary and occurred singly, in pairs, or occasionally in short chains on SNA. Molecular tests consisted of sequencing and phylogenetic analysis of the translation elongation factor-1 alpha (EF-1α), RNA polymerase II largest subunit, and second largest subunit regions. All the obtained sequences revealed 98.14 to 100% identity to F. solani in both Fusarium ID and Fusarium MLST databases. Phylogenetic trees of the EF-1α gene and concatenated three-locus data showed that isolates from tobacco in Henan grouped in the proposed group 5, which is nested within FSSC clade 3 (FSSC 5). Twenty-seven of the 28 isolates caused root rot in artificially inoculated tobacco seedlings, with a disease severity index ranging from 15.00 ± 1.67 to 91.11 ± 2.22. Cross-pathogenicity tests showed that three representative isolates were virulent to six species of Solanaceae and two species of Poaceae, with disease severity indexes ranging from 6.12 ± 0.56 to 84.44 ± 0.00, indicating that these isolates have a wide host range. The results may inform the control of tobacco root rot through improved crop rotations.

Solar Window Innovations: Enhancing Building Performance through Advanced Technologies

Building-integrated photovoltaic (BIPV) glazing systems with intelligent window technologies enhance building energy efficiency by generating electricity and managing daylighting. This study explores advanced BIPV glazing, focusing on building-integrated concentrating photovoltaic (BICPV) systems. BICPV integrates concentrating optics, such as holographic films, luminescent solar concentrators (LSC), Fresnel lenses, and compound parabolic concentrators (CPCs), with photovoltaic cells. Notable results include achieving 17.9% electrical efficiency using cylindrical holographic optical elements and crystalline silicon cells at a 3.5× concentration ratio. Dielectric CPCs showed 97.7% angular acceptance efficiency in simulations and 94.4% experimentally, increasing short-circuit current and maximum power by 87.0% and 96.6%, respectively, across 0° to 85° incidence angles. Thermochromic hydrogels and thermotropic smart glazing systems demonstrated significant HVAC energy savings. Large-area 1 m2 PNIPAm-based thermotropic window outperformed conventional double glazing in Singapore. The thermotropic parallel slat transparent insulation material (TT PS-TIM) improved energy efficiency by up to 21.5% compared to double glazing in climates like London and Rome. Emerging dynamic glazing technologies combine BIPV with smart functions, balancing transparency and efficiency. Photothermally controlled methylammonium lead iodide PV windows achieved 68% visible light transmission, 11.3% power conversion efficiency, and quick switching in under 3 min. Polymer-dispersed liquid crystal smart windows provided 41–68% visible transmission with self-powered operation.

Incoming Inspection of Lithium‐Ion Batteries Based on Multi‐cell Testing

Incoming inspections of battery cells prior to module assembly help to ensure the quality of the battery system and prevent the installation of anomalous cells. Depending on the area of application, identifying deviations in the electrical behavior of the battery cells under test can be essential for downstream assembly processes like cell matching and algorithm adaptations of the battery management software. In this work, the use of a multi‐cell testing procedure involving differential voltage analysis, incremental capacity analysis, direct current internal resistance tests, and electrochemical impedance spectroscopy is investigated to reveal differences in cell properties and identify anomalous cells while economizing on the required cell test channels. The results obtained from 20 model‐identical 21700 cylindrical cells from four different batches demonstrate that this methodology can detect material variations, such as differing silicon and graphite content, which are not disclosed by the supplier or indicated in the data sheet. A teardown with elemental analysis of two cells from different batches is carried out as verification. Finally, prospects for potential application scenarios and raw measurement data are provided.

Thermal Variation on 18650 Cylindrical Cells under Different Testing Arrangement

Cylindrical cell, especially with the 18650 format, is widely used for power electronics and electric vehicle. The cell's performance is strongly dictated by the current rate of charge/discharge and the cell temperature. The former is relatively easy to gauge because the value is constant for a certain period. Therefore, the cell performance can be mapped with respect to the current rate. However, the cell temperature varies temporally and dimensionally, making mapping cell performance concerning temperature difficult. This study employs a comprehensive thermal approach, with the aim to evaluate the degree of thermal variation with respect to various testing temperatures and cell arrangements conducted in a thermal chamber. Thermal measurements are measured, such as cell surface temperature at various cell locations. The experimental results provide an insight that different testing arrangements in which the cell is suspended vertically and horizontally do not alter the temperature variation of the cell significantly. Nevertheless, temperature difference up to 3oC is manifested along the cell surface, which happens at 5oC ambient temperature. This analysis highlights that cell temperature on the surface of 18650 cell is highly non-uniform, and the data could be further used to facilitate the cell's cooling system in for cells in this nature.

Error estimation of Bernardi heat evaluation of Li-ion cells under drive cycle operation

Accurate estimation of heat generation is critical for EV batteries. Conventional means of heat estimation (i.e. Bernardi equation) works only for constant current discharge. However, fluctuating current condition is the normal mode of operation for cells in EV applications. The current study attempts a comprehensive investigation of heat generation and temperature evolution for a cylindrical lithium iron phosphate cell under standard drive cycles (FUDS, US06). An experimentally parameterized electrochemical-heat transfer model is developed. Experimental voltage curve of FUDS drive cycle is used to obtain unknown electrochemical parameters while its fidelity is tested against US06. It is observed that Bernardi method overpredicts heat generation rate by approximately 25% under drive cycle operation. It is noted that Bernardi method is an indirect method of heat estimation based majorly on electrical parameters. It is also observed that the reversible part of Bernardi heat is negligible under drive cycle operation. Moreover, SOC and temperature evolution are accurately estimated by the electrochemical-heat transfer model – errors lie within 7% and 2° C, respectively. Thus, the present study demonstrates the capability of the electrochemical-heat transfer model for estimating heat generation rate of Li-ion cells under drive cycle operation where Bernardi equation is shown to be an inadequate method.