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In recent years, we have witnessed significant advancements in the production of solar cells with a reduction in cost and an increase in their efficiency. One of the stages in creating advancements in new cells is evaluating their performance under different conditions using simulations before their fabrication. In this article, the structure of a multi-junction solar cell composed of Ge layers, InAlGaAs alloys, and InAlGaP alloys will be comprehensively examined. To achieve the highest efficiency, the lowest absorbing layer of the solar cell (Ge solar cell) will initially be optically simulated and then electrically simulated. After optimizing the Ge solar cell, the intermediate layers between the cells (tunnel junctions) and then the upper absorbing layers will be optimized in sequence. Optimization of solar cells in each absorbing layer refers to selecting the appropriate thickness, impurity density, and molar percentage of the layers to achieve the highest efficiency. According to simulation results, an efficiency of over 49% has been achieved for the 5-junction cell. [ABSTRACT FROM AUTHOR]

Abstract Currently, polycyclic aromatic compounds in organic solar cells (OSCs) have gained substantial consideration in research communities due to their promising characteristics. Herein, polycyclic aromatic hydrocarbons (PAHs) core-based chromophores (TTFD1-TTFD6) were designed by structural modifications of peripheral acceptor groups into TTFR. The density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculations were carried out at B3LYP/6-311G (d, p) functional to explore insights for their structural, electronic, and photonic characteristics. The structural modulation unveiled notable electronic impact on the HOMO and LUMO levels across all derivatives, leading to decreased band gaps. All the designed compounds exhibited band gap ranging from 2.246 to 1.957 eV, along with wide absorption spectra of 897.071-492.274 nm. An elevated exciton dissociation rate was observed due to the lower binding energy values (E b = 0.381 to 0.365 eV) calculated in the derivatives compared to the reference (E b = 0.394 eV). Furthermore, data from the transition density matrix (TDM) and density of states (DOS) also corroborated the effective charge transfer process. Comparable results of V oc for reference and designed chromophores were obtained via HOMOdonor−LUMOPC71BM. The declining V oc order values was noted as TTFD5 > TTFD6 > TTFD4 > TTFD3 > TTFD2 > TTFD1 > TTFR. Interestingly, TTFD5 was found with the smallest energy gap and highest absorption value, resulting in better charge transference among all the derivatives. The results illustrated that the modification in indenofluorene based chromophores with end-capped small acceptors proved to be a significant approach in achieving favorable photovoltaic properties.

Currently, polycyclic aromatic compounds in organic solar cells (OSCs) have gained substantial consideration in research communities due to their promising characteristics. Herein, polycyclic aromatic hydrocarbons (PAHs) core-based chromophores (TTFD1-TTFD6) were designed by structural modifications of peripheral acceptor groups into TTFR. The density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculations were carried out at B3LYP/6-311G (d, p) functional to explore insights for their structural, electronic, and photonic characteristics. The structural modulation unveiled notable electronic impact on the HOMO and LUMO levels across all derivatives, leading to decreased band gaps. All the designed compounds exhibited band gap ranging from 2.246 to 1.957 eV, along with wide absorption spectra of 897.071-492.274 nm. An elevated exciton dissociation rate was observed due to the lower binding energy values (Eb = 0.381 to 0.365 eV) calculated in the derivatives compared to the reference (Eb = 0.394 eV). Furthermore, data from the transition density matrix (TDM) and density of states (DOS) also corroborated the effective charge transfer process. Comparable results of Voc for reference and designed chromophores were obtained via HOMOdonor−LUMOPC71BM. The declining Voc order values was noted as TTFD5 > TTFD6 > TTFD4 > TTFD3 > TTFD2 > TTFD1 > TTFR. Interestingly, TTFD5 was found with the smallest energy gap and highest absorption value, resulting in better charge transference among all the derivatives. The results illustrated that the modification in indenofluorene based chromophores with end-capped small acceptors proved to be a significant approach in achieving favorable photovoltaic properties. [ABSTRACT FROM AUTHOR]

This work provides an extended description of the tools developed in the Wolfram Mathematica environment to characterize proton exchange membrane (PEM) fuel cells. These tools, with their user-friendly interface, facilitate the calculation of the main parameters required to obtain the PEM fuel cell polarization curve, offering a seamless and intuitive experience. Various mathematical models and algorithms are coded to accurately calculate the parameters needed for the polarization curve analysis. This study presents the development and validation of a computational tool designed to simulate the performance of proton exchange membrane (PEM) fuel cells. The tool integrates thermodynamic and electrochemical equations to predict key operational parameters, and was validated using experimental data from a commercial Ballard® PEM fuel cell to ensure its accuracy. The validation process involved comparing the numerical predictions with empirical measurements under various operating conditions. The results demonstrate that the computational tool accurately replicates the performance characteristics observed in the experimental data, confirming its reliability and instilling confidence in its use for simulating PEM fuel cell behavior. This tool offers a valuable resource for optimizing fuel cell design and operation, providing insights into the efficiency, output, and potential areas for improvement. Future work will expand the tool's capabilities to include degradation mechanisms and long-term performance predictions. This advancement underscores the tool's potential as a comprehensive solution for academic research and industrial applications in fuel cell technology. [ABSTRACT FROM AUTHOR]

The lead-free CH3NH3SnI3 perovskite is essential for absorbing light in perovskite solar cells (PSCs). In a photovoltaic (PV) device setup of FTO/STO/CH3NH3SnI3/Spiro-OMeTAD/Au, it demonstrates excellent PV performance. This device includes sulfur-doped tin oxide (STO) for the layer of electron transport (ETL), CH3NH3SnI3 as the absorber, and the hole transport layer (HTL) is Spiro-OMeTAD. The upper and back contacts consist of fluorine-doped tin oxide (FTO) and gold (Au), connecting these layers. Several parameters were estimated using the Solar Cell Capacitance Simulator (SCAPS-1D) program, including the thickness, acceptor and donor densities, series and shunt resistances, and temperature. The absorber, HTL, ETL, and FTO thicknesses were set at 1000 ​nm, 100 ​nm, 150 ​nm, and 50 ​nm, respectively, to find the perfect configuration. Densities of acceptors and donors were maintained at 1019 ​cm−3, 2.0 ​× ​1019 ​cm−3, 2.0 ​× ​1018 ​cm−3, and 1018 ​cm−3 for the absorber, HTL, ETL, and FTO, respectively, at an operating temperature of 300K. The device configuration exhibited reduced series resistance and increased shunt resistance, optimized with a back contact metal of Au. The idealized model demonstrated significant PV execution characteristics, including 1.117 ​V for open-circuit voltage (VOC), 28.88 ​mA/cm2 for short-circuit current density (JSC), 88.47 ​% for fill factor (FF), and 28.55 ​% for power conversion efficiency (PCE) under the AM1.5G spectrum. Additionally, the device displayed an average quantum efficiency (QE) of approximately 88.30 ​% at visible light wavelengths.

Abstract To improve the efficacy of organic solar cells (OSCs), novel small acceptor molecules (CTD1–CTD7) were designed by modification at the terminal acceptors of reference compound CTR. The optoelectronic properties of the investigated compounds (CTD1–CTD7) were accomplished by employing density functional theory (DFT) in combination with time-dependent density functional theory (TD-DFT). The M06 functional along with a 6-311G(d,p) basis set was utilized for calculating various parameters such as: frontier molecular orbitals (FMO), absorption maxima (λ max), binding energy (E b), transition density matrix (TDM), density of states (DOS), and open circuit voltage (V oc ) of entitled chromophores. A red shift in the absorption spectra of all designed chromophores (CTD1–CTD7) was observed as compared to CTR, accompanied by low excitation energy. Particularly, CTD4 was characterized by the highest λ max value of 685.791 nm and the lowest transition energy value of 1.801 eV which might be ascribed to the robust electron-withdrawing end-capped acceptor group. The observed reduced binding energy (Eb) was linked to an elevated rate of exciton dissociation and substantial charge transfer from central core in HOMO towards terminal acceptors in LUMO. These results were further supported by the outcomes from TDM and DOS analyses. Among all entitled chromophores, CTD4 exhibited bathochromic shift (685.791 nm), minimum HOMO/LUMO band gap of 2.347 eV with greater CT. Thus, it can be concluded that by employing molecular engineering with efficient acceptor moieties, the efficiency of photovoltaic materials could be improved.

Abstract In this paper the influence of different parameters such as active layer thickness, light intensity and charge separation distance on the photocurrent-voltage, short circuit current density (Jsc) and open circuit voltage (Voc) characteristics in MEH-PPV:PCBM BHJ devicesis studied. For this purpose, the numerical continuum modelbased on drift-diffusion approximation is used. The J-V characteristics of MEH-PPV:PCBM BHJ devices under illumination change considerably with varying the active layer thickness from 40nm to 280nm. In these devices, as the active layer thickness increases from 40 nm to 120 nm the short-circuit current density increases dramatically. The open circuit voltage (Voc) is partially affected by varying the active layer thickness. In these devices, as the light intensity increases, the current density would increase at low voltages. Also, as the charge separation distance “a” increases, The exciton dissociation rate (kdissnexc) and current density would decrease.

To improve the efficacy of organic solar cells (OSCs), novel small acceptor molecules (CTD1–CTD7) were designed by modification at the terminal acceptors of reference compound CTR. The optoelectronic properties of the investigated compounds (CTD1–CTD7) were accomplished by employing density functional theory (DFT) in combination with time-dependent density functional theory (TD-DFT). The M06 functional along with a 6-311G(d,p) basis set was utilized for calculating various parameters such as: frontier molecular orbitals (FMO), absorption maxima (λmax), binding energy (Eb), transition density matrix (TDM), density of states (DOS), and open circuit voltage (Voc) of entitled chromophores. A red shift in the absorption spectra of all designed chromophores (CTD1–CTD7) was observed as compared to CTR, accompanied by low excitation energy. Particularly, CTD4 was characterized by the highest λmax value of 685.791 nm and the lowest transition energy value of 1.801 eV which might be ascribed to the robust electron-withdrawing end-capped acceptor group. The observed reduced binding energy (Eb) was linked to an elevated rate of exciton dissociation and substantial charge transfer from central core in HOMO towards terminal acceptors in LUMO. These results were further supported by the outcomes from TDM and DOS analyses. Among all entitled chromophores, CTD4 exhibited bathochromic shift (685.791 nm), minimum HOMO/LUMO band gap of 2.347 eV with greater CT. Thus, it can be concluded that by employing molecular engineering with efficient acceptor moieties, the efficiency of photovoltaic materials could be improved. [ABSTRACT FROM AUTHOR]

This study focuses on conceptualization and development of a battery management system (BMS) with two main functions, battery monitoring and management, in the context of brushless direct current motors (BLDCs). The main challenge in variable estimation is to protect the battery from potential risks during the charge and discharge cycle. The new proposed resolution combines a comprehensive BMS with monitoring capabilities for charge (SoC), health (SoH), voltage, current and battery temperature. In addition, a protective mechanism is incorporated to prevent variables from overshooting safety parameters. This research uses two different methodologies for estimating SOC, coulomb counting and open circuit voltage. In experimental tests, resistance potentiometers of 1,650, 3,300 and 0 were used, with SoC estimates of 37%, 19% and 65%, while coulomb counting method has a marginal error of 1.13%. On the contrary, the open-circuit voltage method generated a SoC estimate of 0% for all potentiometer resistance, with an error rate of 0.64 %. As a result, the open circuit voltage method is chosen because of its superior accuracy compared to the coulomb counting method. The state assessment of the battery showed a value of 100% after seven cycles. In addition, a protective system has been implemented to ensure that battery variables remain within the safe thresholds throughout the charge and discharge process. Consequently, the implementation of this BMS is expected to significantly improve overall performance and extend battery life.

Most investigations on flow batteries (FBs) make the assumption of perfectly mixed electrolytes inside the tanks without estimating their likelihood, while specific analyses are missing in the literature. This paper presents a pioneering investigation of the electrolyte flow dynamics inside FB tanks. This study considers the Open Circuit Voltage (OCV) measured at the stack of a 9 kW/27 kWh Vanadium FB with 500 L tanks. Order-of-magnitude estimates of the measured dynamics suggest that differences in densities and viscosities of the active species drive gradients of concentrations with different patterns in the positive and negative tanks and in charge and discharge, affected by current and flow rate, which result in significant deviation from homogeneity, affecting the State of Charge (SoC) of the electrolytes flowed into the stack and thus the FB performance. In particular, stratifications of the inlet electrolytes may appear which are responsible for delays in reaching the outlets, with initial plateau and following step (s) in the SoC at the stack. These events can have a major impact in the performance of industrial FBs with large tanks and suggest that specific tank designs may improve the overall dynamics, calling for further analysis. [ABSTRACT FROM AUTHOR]

Context: The purpose of the S01–S05 series of end-capped modified donor chromophores is to amplify the energy conversion efficiency of organic solar cells. Using quantum chemical modeling, the photophysical and photoelectric characteristics of the S01–S05 geometries are examined. Method: The influence of side chain replacement on multiple parameters, including the density of states (DOS), molecular orbital analysis (FMOS), exciton-binding energy (Eb), molecular electrostatic potential analysis, dipole moment (μ), and photovoltaic characteristics including open circuit voltage (VOC), and PCE at minimal energy state geometries, has been investigated employing density functional theory along with TD-DFT analysis. The molar absorption coefficient (λmax) of all the proposed compounds (S01–S05) was efficiently enhanced by the terminal acceptor alteration technique, as demonstrated by their scaling up with the reference molecule (SR). Among all molecules, S04 has shown better absorption properties with a red shift in absorption having λmax at 845 nm in CHCl3 solvent and narrow energy gap (EG) 1.83 eV with least excitation energy (Ex) of 1.4657 eV. All created donors exhibited improved FF and VOC than the SR, which significantly raised PCE and revealed their great efficiency as OSC. Consequently, the results recommended these star-shaped molecules as easily attainable candidates for constructing extremely efficient OSCs. [ABSTRACT FROM AUTHOR]

The non-fullerene acceptor (NFA) chromophores have sparked scientific and economic interest, due to their rapid advancements in power conversion efficiencies. Therefore, a series of new chlorothiazole based compounds (STM1-STM6) with A1–π–A2–π–A1 configuration was designed using reference chromophore (STMR). Structural modifications were made via incorporating selenophene and extended acceptor units, to enhance photovoltaic response in the designed materials. Density functional theory/time dependent-density functional theory (DFT/TD-DFT) calculations were executed at M06/6-311G (d,p) level to investigate key electronic and photovoltaic properties of STM1-STM6. So, various analyses such as UV–Visible, frontier molecular orbitals (FMOs), transition density matrix (TDM), density of states (DOS), open circuit voltage (Voc) and binding energy (Eb) were conducted to comprehend the photovoltaic properties. The designing in structural aspects with terminal acceptors and π-linker induced a reduction in energy gaps (ΔE = 2.078–2.237 eV) with an enhancement in the bathochromic shift (λmax = 744.650–798.250 nm in chloroform) than reference compound. A higher exciton dissociation rate was observed in all the compounds due to lower binding energy values (Eb = 0.525–0.572 eV). Additionally, TDM and DOS findings further endorsed the effective charge delocalization from HOMO to LUMO. Among all the examined compounds, STM3 exhibited the smallest band gap (2.078 eV), highest absorption maxima (798.250 nm), and the lowest exciton binding energy (0.525 eV), indicating significant electronic properties. Moreover, Voc analysis was conducted with respect to HOMOPBDBT-LUMOacceptor for all the designed chromophores; consequently, STM2 demonstrated a substantial Voc value of 1.647 V. Similarly, electron hole analysis was also conducted and significant electron and hole density was observed in all the investigated compounds, especially in STM2. The entitled compounds with photovoltaic potential would be considered as promising materials for the development of solar energy devices.

Abstract Photoinduced intermolecular charge transfer (PICT) determines the voltage loss in bulk heterojunction (BHJ) organic photovoltaics (OPVs), and this voltage loss can be minimized by inducing efficient PICT, which requires energy‐state matching between the donor and acceptor at the BHJ interfaces. Thus, both geometrically and energetically accessible delocalized state matching at the hot energy level is crucial for achieving efficient PICT. In this study, an effective method for quantifying the hot state matching of OPVs was developed. The degree of energy‐state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor (MF) calculated from the modified optical density of the BHJ. Furthermore, the correlation between the open‐circuit voltage (Voc) of the OPV device and energy‐state matching at the BHJ interface was investigated using the calculated MF. The OPVs with small absolute MF values exhibited high Voc values. This result clearly indicates that the energy‐state matching between the donor and acceptor is crucial for achieving a high Voc in OPVs. Because the MF indicates the degree of energy‐state matching, which is a critical factor for suppressing energy loss, it can be used to estimate the Voc loss in OPVs.

In this article, a project of portable photoelectric and photo thermal devices with a power of 60W based on crystalline silicon photoelectric batteries for the production and use of electricity and hot water for household needs in the rural areas of the republic was created. This natural experiment served two purposes. The first is to determine the optimal type for the climate when the various types of PVs available in the local commercial market are used in hot climates. Second, the results of determining and comparing the changes in parameters and energy efficiency of PV and PVT with the same base and capacity at the same time under the same conditions are presented. The results of the study of the parameters that increase their effectiveness have been considered. Special attention is paid to modern components and equipment so that these devices are relatively compact and convenient to operate and control occurs easily.

The article presents the results of studying the electric and thermal efficiency of mobile photovoltaic and photothermal devices (MPVD and MPTD) based on crystalline silicon with a power of 60W panel, designed for the production of electricity and hot water for the domestic needs of rural residents. Our experiment conducted in natural conditions was carried out in the heliopolygon of the Physical-Technical Institute in July of the summer season. The device was manually adjusted and measurements were carried out in the directed mode. Reflectors are installed on the side of the photovoltaic panel (PV) in order to increase the intensity of sunlight in MPTD. As a cooling system, heat collector (HC) is installed in the back of the PV. The HC of the photothermal panel (PVT) is fundamentally different from the system of HC in other works. During the experiment carried out in natural conditions, the effects of the reflectors installed on the front surface of the photothermal device’s PV and the heat collector attached to the back side were determined. Thermal efficiency was 5.5-6 times higher than electric efficiency for PVT panels. And 90% of the solar energy falling on the surface of the photothermal device is converted into useful energy.

In March 2024 — based on computer simulation — it was reported that 2-junction 1.5 eV CdTe/0.87 eV FeSi2 solar cells can achieve actual power conversion efficiency of 43.9 %, open circuit voltage of 1.928 V, and fill factor of 89.88 % at 300 K when the cells are irradiated by the air mass 1.5 global (AM1.5G) solar spectrum [M. H. Tonmoy et al., Heliyon 10 (2024) e27994]. These simulated values exceed the ideal detailed balance-limiting power conversion efficiency, open circuit voltage, and fill factor of a 1.5 eV/0.87 eV 2-junction solar cell.

We have simulated the effect of changing the end groups in BTP core with five organic units of 1,3-Indandione (IN), 2-thioxothiazolidin-4-one (Rhodanine), propanedinitrile (Malononitrile), (2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile) (CPTCN) and 2-(3-oxo-2,3-dihydroinden-1-ylidene (IC), and two halogenated units of (4F) IC and (4Cl) IC on the optical and photovoltaic properties of the BTP DA'D core molecular unit. Thus modified, seven molecular structures are considered and their optical properties, including HOMO and LUMO energies and absorption spectra are simulated in this paper. On the basis of HOMO and LUMO energies, it is found that two of the seven molecules, BTP-IN and BTP-Rhodanine, can act as donors and the other four, BTP-(4F) IC, BTP-(4Cl) IC, BTP-CPTCN and BTP-IC, as acceptors in designing bulk heterojunction (BHJ) organic solar cells (OSCs). Using these combinations of donors and acceptors in the active layer, eight BHJ OSCs, such as BTP-IN: BTP-(4F) IC, BTP-IN: BTP-(4Cl) IC, BTP-IN: BTP-CPTCN, BTP-IN: BTP-IC, BTP-Rhodanine: BTP-(4F) IC, BTP-Rhodanine: BTP-(4Cl) IC, BTP-Rhodanine: BTP-CPTCN and BTP-Rhodanine: BTP-IC, are designed, and their photovoltaic performance is simulated. The photovoltaic parameters J s c , V o c and FF for all eight BHJ OSCs and their power conversion efficiency (PCE) are simulated. It is found that the BHJ OSC of the BTP-IN: BTP-CPTCN donor–acceptor blend gives the highest PCE (14.73%) and that of BTP-Rhodanine: BTP-(4F) IC gives the lowest PCE (12.07%). These results offer promising prospects for the fabrication of high-efficiency BHJ OSCs with the blend of both donor and acceptor based on the same core structure. [ABSTRACT FROM AUTHOR]

Context: Various innovative molecules have been designed and explored for use in organic photovoltaics. In this study, we devised novel molecules (KZ1–KZ7) specifically for organic solar cells (OSCs). The newly formulated acceptor compounds possess a lower bandgap (Eg = 1.85–2.02), along with bathochromic shift (λmax = 713–788 nm) compared to the reference (Eg = 2.04 eV and λmax = 774 nm). Moreover, the FMO results identified the distinct charge transfer from HOMO to LUMO, which was strongly corroborated by the TDM maps. Similarly, the new designed molecules show less excitation energy (Ex = 1.31–1.54(gas)) than reference (Ex = 1.72). Likewise, all designed molecules (KZ1–KZ7) have demonstrated an analogous open circuit voltage (Voc) with the donor polymer PTB7-Th. All seven designed molecules (KZ1–KZ7) exhibited more fill factor ranging from 97.08 to 97.29 than reference 95.25 and PCE of between 8 and 20% at short circuit current densities of 9, 12, and 15 mA cm−2. Overall, the findings support that designed molecules can be potential molecules for future practical applications. Methods: Geometric calculations were conducted with Gaussian 09W software, and the findings were visualized using Gauss View software. DFT and TD-DFT were employed to evaluate various parameters for R and designed molecules (KZ1–KZ7). Firstly, four functionals including B3LYP, CAM-B3LYP, MPW1PW91, and ωB97XD with 6-31G(d,p) DFT level were applied to R to decide the best level for results. After appropriate analysis, the MPW1PW91/6-31G(d,p) was selected for further examination by comparing the experimental and DFT-based absorption graphs of R. External and internal reorganization energy are the two main factors contributing to reorganization energy. External energy refers to changes in external environment, while internal energy deals with information related to internal geometrical symmetry or the internal environment. The effect of outside factors or external reorganizational energy is omitted because it creates too little change. [ABSTRACT FROM AUTHOR]

The power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) has reached 26.1% in small-scale devices. However, defects at the bulk, surface, grain boundaries, and interfaces act as non-radiative recombination centers for photogenerated electron-hole pairs, limiting the open-circuit voltage and PCE below the Shockley–Queisser limit. These defect states also induce ion migration towards interfaces and contribute to intrinsic instability in PSCs, reducing the quasi-Fermi level splitting and causing anomalous hysteresis in the device. The influence of defects becomes more prominent in large-area devices, demonstrating much lower PCE than the lab-scale devices. Therefore, commercializing PSCs faces a big challenge in terms of rapid decline in working performance due to these intrinsic structural defects. This paper provides a comprehensive review of recent advances in understanding the nature and the classification of defects, their impact on voltage losses, device parameters, intrinsic stability, and defect quantification and characterization techniques. Novel defect passivation techniques such as compositional engineering, additive engineering, post-treatments, dimensionality engineering, and interlayer engineering are also reviewed, along with the improvements in PCE and stability based on these techniques for both small-area devices and large-area roll-to-roll coated devices. [ABSTRACT FROM AUTHOR]

Keeping in view, the recent energy conditions and contribution of non-fullerene acceptors (NFAs) towards organic solar cells (OSCs), a series of NFAs (D1-D9) was designed. The novel fused ring NFAs (D1-D9) having A-D-A architecture were designed by structural engineering of R molecule with effective benzothiophene based acceptor moieties. For current study, all the calculations were accomplished at M06/6-311G (d,p) level. Different computational approaches like density of states (DOS), binding energy (Eb), transition density matrix (TDM), absorption spectra (UV–Vis), electronic properties (FMOs) and open circuit were performed to investigate the photovoltaic response of newly designed D1-D9 chromophores. The terminal substitution of end-capped acceptors exhibited a reduction in energy gap (ΔE = 2.222–1.986 eV) with high electron mobility rate in all the derivatives (D1-D9) than that of R. All the designed chromophores exhibited wider absorption spectrum (λmax = 845.039–786.552 nm) along with lower excitation energy as compared to R (λmax = 770.040 nm) except D1 and D9. Interestingly, lower binding energy (Eb = 0.419–0.473 eV) accompanying with higher excition dissociation rate was seen in derivatives than that of reference compound. Moreover, a comparable value of Voc was noted in derivatives when calculated via LUMOacceptor–HOMOPBDBT. Among all fore-said chromophores (D1-D9), D4 exhibited lowest binding energy and thus ensured easier and faster excition dissociation rate along with highest Voc (1.586 V). In cessation, this structural modification by utilizing various acceptors played a significant role in obtaining auspicious photovoltaic response in compounds. Hence, our study encourages the experimentalists for synthesizing these proposed organic systems for the attaining high efficacy photovoltaic devices.

Herein, a series of pyrazoline based non-fullerene compounds (THP1-THP8) having ladder-like backbone was designed by structural modulation with various electron accepting moieties. The density functional theory (DFT) and time-dependent functional theory (TD-DFT) study was executed at M06/6-311G(d,p) level for structural optimization and to determine the electronic and optical characteristics of the pyrazoline based chromophores. The optimized structures were employed to execute frontier molecular orbital (FMO), transition density matrix (TDM), density of state (DOS), open circuit voltage (Voc) and reorganization energy analyses at the aforementioned level of DFT to comprehend the photovoltaic (PV) response of THP1-THP8. The red-shifted absorption spectrum (512.861–584.555 nm) with reduced band gap (2.507–2.881 eV) allow considerable charge transferal from HOMO to LUMO in all the studied compounds. Global reactivity parameters (GRPs) demonstrated high softness with considerable reactivity in THP1-THP8. Moreover, remarkable Voc values (2.083–2.973 V) were noted for all the derivatives (THP1-THP8). However, THP2 with lowest energy gap (2.364 eV), highest λmax (617.482 nm) and softness (0.423 eV) values is considered good candidate among afore-said chromophores. Hence, the studied chromophores with efficient properties are appropriate for experimentalists in terms of manufacturing of efficient OSCs.

The needs of the population and industry for electrical energy are limited by oil and gas reserves, which leads to the need to use renewable energy sources. Myanmar is one of the developing countries in Asia. Its specific power consumption is low compared to neighboring countries. Currently, one of the most important tasks of the electric power industry is to ensure reliable, uninterrupted power supply to all industrial and domestic facilities. At the same time, the development of small solar photovoltaic installations (PMT), operating both in parallel with the grid and in autonomous mode, can improve the power supply of closely located consumers more efficiently and faster than the development of a large power system. Therefore, the work devoted to the improvement of the equipment of a small solar photovoltaic installation is relevant and of great practical importance.

In this study, the temperatures of the front glass, back sheet, and solar cell (SC) in the rear electrical contact of the PV module during heating, and the open circuit voltage and short circuit current corresponding to these temperatures were experimentally investigated. Measurements were conducted in the city of Termez in conditions of an air temperature of 30ºC and solar radiation intensity of 850-950W/m2 . Two mono c-Si PV modules with the same electric power were selected for the experiment. Three K-type chrome and alumn combined thermocouples were used to measure the temperatures in the layers of the first PV module. During the observations, it was found that the temperature of the PV module glass differs from the back sheet temperature by ~20ºC, and from the temperature of the back electrical contact of the SC by ~25ºC. Also, according to the temperature difference, the open circuit voltage of the PV module decreased from 21V to 19.3V, and the short circuit current increased from 0.65A to 0.75A. During the experiment, the values of electric power changed by ~11-11.6W.

A microbial fuel cell (MFC) is a renewable source of energy that produces electricity without harming the environment. This review paper describes the importance of MFCs for future power sources. The construction methods, history of MFC, different configuration of MFC and voltage generation of single-chamber as well as the two-chamber MFC have been discussed. Due to the bio-electrochemical features of the MFCs, when an electric load is applied to stack MFCs, Stack MFC’s voltage does not remain constant over time (known as reversal of voltage). Therefore, researchers have proposed various power management systems (PMS) to raise the voltage of the MFC to avoid voltage reversal. The future direction is focus on the design of a PMS adapted for MFC optimal operation using ultralow power consumption components.

The power conversion efficiency (PCE) of ternary polymer solar cells (PSCs) with non-fullerene has a phenomenal increase in recent years. However, improving the open circuit voltage (Voc) of ternary PSCs with non-fullerene still remains a challenge. Therefore, in this work, machine learning (ML) algorithms are employed, including eXtreme gradient boosting, K-nearest neighbor and random forest, to quantitatively analyze the impact mechanism of Voc in ternary PSCs with the double acceptors from the two aspects of photovoltaic materials. In one aspect of photovoltaic materials, the doping concentration has the greatest impact on Voc in ternary PSCs. Furthermore, the addition of the third component affects the energy offset between the donor and acceptor for increasing Voc in ternary PSCs. More importantly, to obtain the maximum Voc in ternary PSCs with the double acceptors, the HOMO and LUMO energy levels of the third component should be around (−5.7 ± 0.1) eV and (−3.6 ± 0.1) eV, respectively. In the other aspect of molecular descriptors and molecular fingerprints in the third component of ternary PSCs with the double acceptors, the hydrogen bond strength and aromatic ring structure of the third component have high impact on the Voc of ternary PSCs. In partial dependence plot, it is clear that when the number of methyl groups is four and the number of carbonyl groups is two in the third component of acceptor, the Voc of ternary PSCs with the double acceptors can be maximized. All of these findings provide valuable insights into the development of materials with high Voc in ternary PSCs for saving time and cost. [ABSTRACT FROM AUTHOR]

This paper presents the results of electrical simulations at different active thickness layers of hybrid photovoltaic devices using GPVDM software. A combination of inorganic n-type semiconductor SiGe and organic p-type semiconductor PTAA has been chosen to be simulated in this research work. The thickness of SiGe and PTAA varies from 100 nm – 500 nm and 1000 rpm – 5000 rpm. The results show that the thickness of both semiconductor affects the electrical properties. Higher current density, Jsc, can be obtained as the thickness of SiGe increases. PTAA as an active layer had affected the value of open-circuit voltage, Voc. The SiGe combination with lower rpm depicted a higher value of Voc than the other combinations. The FF and efficiency rate of the solar panel is also presented in this work. This research focuses on the thickness combination of both semiconductors layer on the performance of its electrical characteristics.

The construction of an aluminum-sodium hypochlorite battery is addressed. The battery was made from household chemicals and products obtained from a typical supermarket. The proposed small-scale battery design is easy to assemble and only one cell is needed to light a red light emitting diode (LED). [ABSTRACT FROM AUTHOR]

Many problems arise in the operation of photovoltaic systems. Each of these problems affects the operation of photovoltaic systems by reducing the power of the entire system. Some problems can be avoided during the design of photovoltaic systems. For example, when designing photovoltaic systems, it is possible to eliminate the shading of photovoltaic panels from surrounding objects. It is also necessary to look at the shading from neighboring photovoltaic panels when designing photovoltaic systems. It is necessary to calculate the inclination of the sunlight based on the position of the sun and calculate the distance between the two panels accordingly. However, some problems appear during the operation of photovoltaic systems. These problems can be partially eliminated. The magnitude of the series resistance can be eliminated by reducing the transition resistance throughout the system. The paper describes these problems and their possible solutions in practice. In the practical part, we focused on simulations and experiments in the field of photovoltaic systems (PV). The simulations focused on both the influence of temperature and the series resistance of photovoltaic panels on the production of electricity. The experiments were focused on the influence of various faults/defects on the power and V-A characteristics of photovoltaic panels connected in strings. The paper also discusses the impact of bypass diodes on the operation of photovoltaic systems and determines the need to use bypass diodes. [ABSTRACT FROM AUTHOR]

The efficiency of solar cells depends on the quality of passivation of surface. The quality of passivation is analyzed as a function of the dependence of the open circuit voltage on the light intensity. Therefore, in this article, the dependence of the photoelectric parameters of the silicon-based solar cell on the light intensity was studied. According to the obtained results, it was found that the variation of the short-circuit current through light intensity is equal to 25.6 mA/suns·cm². The agreement of the results obtained in research and modeling with the results of experiments proves the validity and correctness of the model. In this paper, the Sentaurus TCAD model of a silicon-based solar cell is experimentally verified. So, the dependence of the open circuit voltage of the silicon-based solar cell on the light intensity was studied through modeling and experiment. The functional dependence of the open circuit voltage obtained in the modeling satisfied the experiment. Therefore, the model of the solar cell created in Sentaurus TCAD is suitable for research. So, we can use model created in Sentaurus TCAD in our further researches. In addition, the fill factor of solar cell increased with increasing intensity. This proves that the resistive properties of the solar cell are improving. [ABSTRACT FROM AUTHOR]

Vanadium redox flow batteries (VRFB) are a fertile energy storage technology especially for customized storage applications with special energy and power requirements. The dimensioning and control of these storages is mostly calculated beforehand using battery models in embedded simulation structures. To cover various stack designs, chemistries, application strategies and system architectures, battery simulation models should be validated with different experimental input data and thus show universal functionality. In this study the functionality of a grey box VRFB model using current, voltage and state of charge (SOC) of a 10 kW/100 kWh VRFB as input data are validated for an adapted input data set using of a 5 kW/10 kWh VRFB. This model is designed for stationary applications of VRFB only. The contribution of this study is (i) to apply a suitable SOC conversion method to the raw data from the used 5 kW VRFB system, (ii) to adapt the modeling code for broader use and integration of the SOC conversion, (iii) to validate the functionality and (iv) to investigate the influence of constant current and constant voltage phases in the raw data on the accuracy of the model. A comparison of experimental data between different redox flow batteries shows that most VRFB measure the open circuit voltage (OCV) to calculate the SOC of the battery. Using the calculated SOC as an input data the proposed simulation model need to be adapted and a method is applied to use OCV input data for model validation. Although simulation models in general often assume linearity between SOC and OCV, the study showed sufficient accuracy using polynomic fitting of second order. Applying a parametrization process the results of the simulation model are compared to the raw data and the scope of application of the grey box VRFB model is defined. While using the dominant constant current phase for the charging and discharging cycle, the grey box simulation model has been sufficiently parametrized and validated for adapted input data. [ABSTRACT FROM AUTHOR]

[Display omitted] • Application of [Fe 4 S 4 ] to metal-ion batteries is studied using DFT calculations. • Embedding [Fe 4 S 4 ]2+ clusters in metal–organic frameworks generates high voltage. • The electrochemical performance is based on an intercalation mechanism. • Among the screened material pairs, Zn2+-BMOF shows the highest efficiency. [Fe 4 S 4 ] clusters have served as molecular batteries and charge transfer centers in many biosystems. However, their potential as electrode materials has been overlooked amidst the ever-increasing studies on various materials in the search for efficient battery compositions. To evaluate their electrochemical efficiency as electrode materials, we focused on the use of two important oxidation states, [Fe 4 S 4 ]2+ and [Fe 4 S 4 ]⁰, in a series of Li-, Na-, K-, Mg-, Ca-, and Zn-ion batteries. We also assessed the effect of metal–organic framework (MOF) formation on their performance by studying [Fe 4 S 4 ]2+-1,4-benzenedithiolate MOF (BMOF) and its carboxylate-based counterpart (CMOF). Our model-based Density Functional Theory (DFT) calculations indicated that oxidation of the cluster to [Fe 4 S 4 ]2+ and MOF formation significantly improve the electrochemical efficiency of the cluster. Among the studied electrode materials and metals, the BMOF combination with Mg0 and Zn2+ presented the best electrochemical performance. Notably, our periodic calculations indicated an open circuit voltage of 4.32 V for the Zn2+-BMOF system, suggesting a promising performance for BMOF compared to other cathode/negative electrode materials. Our atomic and electronic structure analyses indicated that intercalation is the underlying electrochemical mechanism. [ABSTRACT FROM AUTHOR]

LiFePO4 batteries are increasingly utilized in electric vehicles due to their superior safety. Accurate state estimation is the basis for the safe and reliable application of LiFePO4 batteries. However, the flat voltage characteristics of LiFePO4 batteries lead to state estimation closed-loop correction as its inherent contradiction. To address this challenge, a model-based SOC estimation method combining proportional-integral-differential (PID) observer and improved extended Kalman filter (EKF) is developed according to different open-circuit-voltage (OCV) ranges, specific processes include: First, an exponentially weighted moving average algorithm with a temperature compensation factor is presented to compensate for the errors in the identified OCV. Secondly, the combination of the PID observer and EKF is chosen adaptively to update SOC within distinct OCV ranges, differentiated by the identified OCV. To achieve optimization of the PID parameters and temperature compensation factors across varying temperatures, an enhanced whale optimization algorithm is developed. To validate the developed method, a series of experiments are performed across a range of temperatures and with multiple driving profiles. The results show that the developed method not only guarantees maximum absolute error of <3 %, but also can converge quickly in the early stage. • A temperature compensation factor (T c) is used to reduce the error of identified OCV based on EWMA-FFRLS. • A PIDO combined with an improved AEKF is presented to accelerate the SOC convergence speed. • An AEKF-PIDO-integrated US-EKF framework is developed to enhance SOC estimation of LiFePO4 battery. • An improved WOA is introduced to adjust the PIDO parameters and T c at different temperatures. [ABSTRACT FROM AUTHOR]

A battery source is an indispensable component in electric vehicles and its efficient usage results in improvement of battery life. The amount of energy stored in batteries, including their state of charge and efficiency, are critical metrics for evaluating vehicle performance. This article presents an automated motor-generator linked technique for estimating battery-related parameters, which is an essential aspect of eco-routing in electric vehicles. This system enables discharging of a battery at various current rates by constant resistive loads which are electronically applied. The charging process however uses a charger attached to various sensors for estimating the current. The coulomb counting method has been used which provides information of State of Charge and Coulombic Efficiency of the test battery. Since battery behavior is dynamic; the energy source was charged and discharged over numerous cycles at various current rates. The experimental set-up uses sensors for accurate data acquisition. In addition to the experimental set-up, an electrical circuit battery model has also been simulated in this work. All simulation as well as post processing tasks have been done in the Arduino-MATLAB environment. The main highlight of this system is that the system is portable, easy to operate, low cost and can be used to test all types of batteries. The proposed system is simple and has yielded good results. The battery parameters obtained prove to be vital for range determination in eco-routing of electric vehicles among other applications.

The photovoltaic (PV) panels are expected to be the most important systems to meet global energy demand by converting solar energy into electricity. The main obstacle to the widespread deployment of the PV systems its the limited efficiency, which are greatly affected by the solar radiation and the operating temperature. The full knowledge of the performance, efficiency and output power of photovoltaic modules and the extent of their change with the fluctuations of solar radiation and temperature is necessary to determine the optimal size of the system and avoid the financial risks of the project. This paper investigated numaricaly and experimentaly the influence of operating temperature and solar radiation on the output power and efficiency of polycrystalline PV panels in Baghdad-Iraq. The PVsyst software was used to simulate a model implementing simulation results presented the impact of variations temperature and solar radiation in the curves of I-V, P-V and efficiency. In order to verify the reliability of the simulated results with experimental ones, several measuring devices have been used to conduct field experiments in the outdoor conditions. It were used to determine the characteristics and performance of a 120W polycrystalline PV panel for different ranges of solar radiation and operating temperature. The simulation results showed that the current, voltage, output power and efficiency increased with increasing solar radiation, while they decreased with increasing temperature except the current that was increased. The experimental and simulated results were identical in terms of the effect of temperature and solar radiation on the current, voltage, output power and efficiency of the PV panel. The experimental tests showed that when the temperature is increased by 1°C, the current was increased by about 0.068%, the voltage decreased by 0.34%, the output power decreased by 0.489% and the efficiency decreased about 0.586%. The experimental results displayed that the parameters of the PV panel under real operating conditions behave differently than in the standard test conditions (STC), as they are strongly affected by weather fluctuations in terms of temperature and solar radiation

We have simulated the effect of changing the end groups in BTP core with five organic units of 1,3-Indandione (IN), 2-thioxothiazolidin-4-one (Rhodanine), propanedinitrile (Malononitrile), (2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile) (CPTCN) and 2-(3-oxo-2,3-dihydroinden-1-ylidene (IC), and two halogenated units of (4F) IC and (4Cl) IC on the optical and photovoltaic properties of the BTP DA’D core molecular unit. Thus modified, seven molecular structures are considered and their optical properties, including HOMO and LUMO energies and absorption spectra are simulated in this paper. On the basis of HOMO and LUMO energies, it is found that two of the seven molecules, BTP-IN and BTP-Rhodanine, can act as donors and the other four, BTP-(4F) IC, BTP-(4Cl) IC, BTP-CPTCN and BTP-IC, as acceptors in designing bulk heterojunction (BHJ) organic solar cells (OSCs). Using these combinations of donors and acceptors in the active layer, eight BHJ OSCs, such as BTP-IN: BTP-(4F) IC, BTP-IN: BTP-(4Cl) IC, BTP-IN: BTP-CPTCN, BTP-IN: BTP-IC, BTP-Rhodanine: BTP-(4F) IC, BTP-Rhodanine: BTP-(4Cl) IC, BTP-Rhodanine: BTP-CPTCN and BTP-Rhodanine: BTP-IC, are designed, and their photovoltaic performance is simulated. The photovoltaic parameters Jsc, Voc and FF for all eight BHJ OSCs and their power conversion efficiency (PCE) are simulated. It is found that the BHJ OSC of the BTP-IN: BTP-CPTCN donor–acceptor blend gives the highest PCE (14.73%) and that of BTP-Rhodanine: BTP-(4F) IC gives the lowest PCE (12.07%). These results offer promising prospects for the fabrication of high-efficiency BHJ OSCs with the blend of both donor and acceptor based on the same core structure.

The power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) has reached 26.1% in small-scale devices. However, defects at the bulk, surface, grain boundaries, and interfaces act as non-radiative recombination centers for photogenerated electron-hole pairs, limiting the open-circuit voltage and PCE below the Shockley–Queisser limit. These defect states also induce ion migration towards interfaces and contribute to intrinsic instability in PSCs, reducing the quasi-Fermi level splitting and causing anomalous hysteresis in the device. The influence of defects becomes more prominent in large-area devices, demonstrating much lower PCE than the lab-scale devices. Therefore, commercializing PSCs faces a big challenge in terms of rapid decline in working performance due to these intrinsic structural defects. This paper provides a comprehensive review of recent advances in understanding the nature and the classification of defects, their impact on voltage losses, device parameters, intrinsic stability, and defect quantification and characterization techniques. Novel defect passivation techniques such as compositional engineering, additive engineering, post-treatments, dimensionality engineering, and interlayer engineering are also reviewed, along with the improvements in PCE and stability based on these techniques for both small-area devices and large-area roll-to-roll coated devices.

Photovoltaic (PV) systems can generate less energy than expected owing to inefficiency of the inverter, deterioration of the PV modules or conditions of partial shading and soiling. The monitoring and diagnosis techniques of PV systems are therefore quite important to recognize the causes of the performances reduction and optimize the PV energy production. For a more in-depth diagnostic capability, it would be necessary to know the short-circuit current (Isc) and the open-circuit voltage (Voc) of the PV system. These quantities are indeed useful to recognize non-uniform operating conditions of the PV modules (partial shadings, malfunctions, generic electro-optical mismatch conditions), estimate the PV module junction temperature and the voltage temperature coefficient. However, so far, these quantities cannot be measured by the inverter in operative conditions. With this contribution we propose and test a new electronic interface for a more advanced diagnostics of the PV system to be easily installed between the PV string and the inverter, able to measure the values of Isc and Voc as well as the inverter voltage, current and power working points, avoiding any downtime of the PV system and minimizing the power losses during the diagnosis activity. [ABSTRACT FROM AUTHOR]

Herein, based on the reviewed literature, the current marketability challenges faced by kesterite CZTS based-solar cells is addressed. A knowledge update about the attempts to reduce the open circuit voltage deficit of kesterite CZTS solar cells will be addressed, with a focus on the impact of Cu/Zn order/disorder and of Se doping. This review also presents the strengths and weaknesses of the most commercially attractive synthesis methods for synthesizing thin kesterite CZTS films for photovoltaic applications. [ABSTRACT FROM AUTHOR]

State of Charge (SoC) is a parameter used to determine the current capacity on a battery as well as indicate the operational characteristics. The SoC is an important parameter for optimizing battery utilization in many applications requiring DC current source. However, estimating the SoC value is the major problem since it cannot be measured directly. In this study, we proposed SoC measurement method based on analysis internal resistance of battery. The internal resistance is correlated with the parameters of the magnitude of the terminal voltage and open circuit. Both voltages come from the influence of current during the charging-discharging process. We report that the proposed method has successfully obtained the correlation between the SoC and the internal resistance value for two process, which are the charging- and discharging process. [ABSTRACT FROM AUTHOR]

Lithium-ion (Li-ion) batteries have increasingly been used in diverse applications. Accurate estimation of the state of health (SOH) of the Li-ion batteries is vital for all stakeholders and critical in various applications such as electric vehicles (EVs). The electrical equivalent circuit (EEC) 2-RC model is often used to model the battery operation but has not been used to capture the degradation of battery cells over time. This paper uses the 2-RC model to capture the degradation of the Li-ion battery. The proposed model is not only time-dependent but also captures the effect of temperature on battery degradation. The proposed approach estimates the SOH accurately and is also considerably flexible for diverse cells of different chemistry. We further generalize an N-RC model approach to evaluate the SOH of the battery. We compare the proposed model (2-RC) with the 1-RC model, and through numerical results, we show that the 2-RC model outperforms 1-RC and reduces the computational cost significantly. Similarly, the 2-RC model outperforms 3-RC and higher-order circuits. We also show that the proposed approach can capture the battery dynamics better for specific smaller orders of the polynomial (associated with Arrhenius equation) when compared with the 1-RC approach with considerably reduced (up to 60%) root mean square error (RMSE). Lastly, the average testing RMSE for 2-RC is 52.4%.

Battery Open Circuit Voltage (OCV) is of fundamental characteristic for enabling battery modeling and states estimation. However, the traditional OCV measurement method takes a very long time to make the battery reaches its equilibrium, which is rather inconvenient and cannot be performed online for battery energy storage application. Motived by this, this paper proposes an effective method for fast OCV estimation in the relaxation process. In this work, a novel relaxation model is designed for capturing the voltage response of a battery during relaxation time and the Genetic Algorithm (GA) is further applied for optimizing the model parameters and acquiring accurate OCV estimation results. Experimental results confirm the validity of the proposed method under different State of Charges (SOCs), current rates, ambient temperatures, and aging conditions. The results suggest that the proposed method can accurately and quickly estimate battery OCV, which only takes 10 minutes of measurement data (more than 2 hours for the traditional method) and the maximum estimation error is limited to merely 1.8 mV.

Anaerobic digestion (AD) can produce renewable energy and reduce carbon emissions, but the energy conversion efficiency is still limited in some waste streams. This study tested the effect of applied voltage removal for microbial electrolysis cells (MECs) treating primary sewage sludge. Two MECs were operated in parallel: a MEC-0.3 V with an applied voltage of 0.3 V and a MEC-OCV with open circuit voltage. Both reactors were inoculated with seed sludge originating from a MEC at 0.3 V applied voltage, and three batch cycles were operated for 36 d. The methane production of the MEC-OCV was 3759 mL/L in the first cycle and 2759 mL/L in the second cycle, which was similar (105% and 103%, respectively) to that of the MEC-0.3 V. However, in the third cycle, the methane production of the MEC-OCV (1762 mL/L) was 38.8% lower than that of the MEC-0.3 V (4545 mL/L). The methane contents in the biogas were 68.6–74.2% from the MEC-OCV, comparable to those from the MEC-0.3 V (66.6–71.1%). These results indicate that not only the MEC-0.3V but also the MEC-OCV outperformed AD in terms of methane yield and productivity, and the promotion using MEC-derived inoculum persisted equally with the MEC-OCV for two batch cycles after removing the applied voltage. Therefore, a MEC operation with cycled power supply may be beneficial in reducing the electric energy usage and improving the biogas production performance, compared to conventional AD. [ABSTRACT FROM AUTHOR]

State of Charge (SOC) is the ratio of current versus total capacity of the battery. In the context of Battery Management System (BMS), the SOC is estimated by using a battery model. In this research, three battery models were presented, including (1) Thevenin battery model, (2) modified Thevenin battery model, and (3) simple battery model. Then, the SOC of those battery models was estimated using Coulomb Counting, Open Circuit Voltage (OCV), and Kalman Filter method. The simulation evaluated the performance of the SOC estimation methods, including the correctability of SOC initialization error. The simulation results showed that the proposed battery models could accurately estimate SOC. In terms of SOC initialization error, the Coulomb Counting, OCV Model 1, and OCV Model 2 could not correct the initialization error of SOC. However, the application of OCV Model 3 and Kalman Filter could provide an accurate SOC estimation with excellent correction of SOC initialization error. Compared to OCV model 3, the error correction in the Kalman Filter method was performed 25 minutes faster. Therefore, this finding suggests that Kalman Filter is the most suitable estimation method for BMS due to the high accuracy of SOC estimation (RMSE = 0.0014) and fast correction of SOC initialization error (time < 20 seconds). [ABSTRACT FROM AUTHOR]

With the wide acceptance of modeling a PV cell by a single diode, a series and parallel resistors; many researchers have discussed different mathematical forms and iterative techniques to extract the values of these model elements depending on the key parameters provided by the manufacturer datasheet. This paper avoids iterative techniques and obtains the values of the five parameters of the one diode model by developing closed form expressions. The maximum error produced by this technique is 10% when compared to the exact values of the one diode model circuit built by Spice. The 10% maximum error has occurred during the estimation of the reverse saturation current (Io) of the diode, nevertheless, it should be mentioned that even for this same parameter the model outperforms many iterative dependent works. Furthermore, this paper discusses the effect of temperature on the operation performance of PV cells. In particular, the temperature effect on the open circuit voltage, the short circuit current, the fill factor, the reverse saturation current, and the conversion efficiency was modeled and evaluated for different brand technologies

In this work, the electrodes of a microbial desalination cell (MDC) are investigated as the positive and negative electrodes of an internal supercapacitor. The resulting system has been named a supercapacitive microbial desalination cell (SC-MDC). The electrodes are self-polarized by the red-ox reactions and therefore the anode acts as a negative electrode and the cathode as a positive electrode of the internal supercapacitor. In order to overcome cathodic losses, an additional capacitive electrode (AdE) was added and short-circuited with the SC-MDC cathode (SC-MDC-AdE). A total of 7600 discharge/self-recharge cycles (equivalent to 44 h of operation) of SC-MDC-AdE with a desalination chamber filled with an aqueous solution of 30 g L-1 NaCl are reported. The same reactor system was operated with real seawater collected from Pacific Ocean for 88 h (15,100 cycles). Maximum power generated was 1.63 ± 0.04 W m-2 for SC-MDC and 3.01 ± 0.01 W m-2 for SC-MDC-AdE. Solution conductivity in the desalination reactor decreased by ∼50% after 23 h and by more than 60% after 44 h. There was no observable change in the pH during cell operation. Power/current pulses were generated without an external power supply.

Open circuit voltage (OCV) is crucial for battery degradation analysis. However, high-precision OCV is usually obtained offline. To this end, this paper proposes a novel self-evaluation criterion based on the capacity difference of State of Charge (SoC) unit interval. The criterion is integrated into extended Kalman filter (EKF) for joint estimations of OCV and SoC. The proposed method is evaluated in a typical application scenario, energy storage system (ESS), using a LiFePO 4 (LFP) battery. Extensive experimental results show that a more accurate OCV and incremental capacity and differential voltage (IC-DV) can be achieved online with the proposed method. Our method also greatly improves the accuracy of SoC estimation at each SoC point where the maximum estimation error of SoC is less than 0.3%. [ABSTRACT FROM AUTHOR]

A battery source is an indispensable component in electric vehicles and its efficient usage results in improvement of battery life. The amount of energy stored in batteries, including their state of charge and efficiency, are critical metrics for evaluating vehicle performance. This article presents an automated motor-generator linked technique for estimating battery-related parameters, which is an essential aspect of eco-routing in electric vehicles. This system enables discharging of a battery at various current rates by constant resistive loads which are electronically applied. The charging process however uses a charger attached to various sensors for estimating the current. The coulomb counting method has been used which provides information of State of Charge and Coulombic Efficiency of the test battery. Since battery behavior is dynamic; the energy source was charged and discharged over numerous cycles at various current rates. The experimental set-up uses sensors for accurate data acquisition. In addition to the experimental set-up, an electrical circuit battery model has also been simulated in this work. All simulation as well as post processing tasks have been done in the Arduino-MATLAB environment. The main highlight of this system is that the system is portable, easy to operate, low cost and can be used to test all types of batteries. The proposed system is simple and has yielded good results. The battery parameters obtained prove to be vital for range determination in eco-routing of electric vehicles among other applications. [ABSTRACT FROM AUTHOR]

Inverted metamorphic triple junction (IMM3J) GaInP/GaAs/InGaAs solar cells have the advantages of high efficiency, excellent radiation resistance, lightweight and flexible properties, especially suitable for space application. In this paper, we first fabricate the IMM3J GaInP/GaAs/InGaAs solar cell, which has a short circuit current density of 16.5 mA/cm2, an open circuit voltage of 3141.8 mV, a fill factor of 84.3%, and an efficiency of 32.2%. Then, the IMM3J solar cell is irradiated by 2 MeV protons with different fluences from 2 × 1011 cm−2 to 2 × 1012 cm−2. Finally, the output electrical properties of IMM3J solar cells at the beginning of life and end of life are analyzed by current-voltage characterization. The degradation behaviors of each subcell before and after irradiation can also be described by the external quantum efficiency and short circuit current density. [ABSTRACT FROM AUTHOR]