Charging Voltage Research Articles

A Room-Temperature All-Solid-State Na-Ag Battery with a Long Cycle Life and Low Overpotential.

Aqueous Zn-Ag batteries have been developed and commercialized for nearly a century, offering stable discharge and high specific energies. Sodium, with its lower redox potential, smaller charge-to-mass ratio, and abundant resources, presents a promising alternative to zinc. In this study, we successfully developed an all-solid-state Na-Ag battery system. This battery demonstrates stable discharge and charge voltages, low overpotential (0.27 V), high energy efficiency (>91%), and long cycle life under moderate humidity at room temperature. The reaction mechanism was elucidated through combined analyses using differential electrochemical mass spectrometry (DEMS), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Our findings indicate that metallic Ag in the cathode materials acts as an effective catalyst for the oxygen reduction reaction during the initial discharge process, forming NaOH as the discharge product. Ag is then oxidized during the charging process and recovered during discharge, serving as an active reactant in the Na-Ag battery. This work demonstrates superior performance of all-solid-state Na-Ag battery over aqueous Zn-Ag battery. Na-Ag battery may be of interest in applications with stringent requirements on stable discharge voltage and high specific energy.

Experimental results of a 330 GW impedance-matched Marx generator

Impedance-matched Marx generators (IMGs) are considered next generation pulsed-power drivers because of their long lifetime (> 10,000 shots), repetition rate (> 0.1-Hz), fast rise time (~ 100-ns), and high-energy-delivery efficiency (~ 90%). “TITAN” is a 14-stage IMG designed to deliver 1-TW to a 2-Ω matched load. In this paper, design, simulation, and experimental results for six stages of TITAN including its triggering system, air delivery system, and pulse shaping are presented. To achieve efficiency over 85% and maximize the capability of an IMG, synchronized triggering, reduced pre-fire rate, and pulse shaping ability are crucial. In this paper, novel engineering solutions are introduced, tested, and proven to overcome those challenges. 6-stage TITAN, powered by 102 identical bricks and 102 field-distortion-triggered gas switches, could generate ~ 600-kA and ~ 700-kV across a ~ 0.9-Ω matched load when fully charged to ± 100-kV. In these experiments, 6-stage TITAN is tested up to ± 70-kV charge voltage which delivers a peak power of 330-GW to a 1.2-Ω resistive load.

Adaptable capacity estimation of lithium-ion battery based on short-duration random constant-current charging voltages and convolutional neural networks

The accurate lithium-ion battery capacity estimation is vital for ensuring the safe and reliable operation of battery-powered systems. Existing data-driven methods heavily rely on fixed charging stages for feature extractions, posing significant limitations in real-world applications. This paper proposes an adaptable capacity estimation approach utilising short-duration random charging voltages during the constant-current charging stage and leveraging convolutional neural networks (CNNs). Based on the user-friendly “Vstart−tend” strategy, two health features including charging voltage and its increment are firstly extracted from random charging segments. Secondly, a feature evolution pattern analysis over the battery's lifespan is proposed to divide the charging voltage range for robust model development. An optimal combination of both the sampling interval and data length is determined for the feature extraction. Then, a two-dimensional CNN model is developed to effectively learn ageing-related knowledge from various random charging segments in a specific charging voltage range. The effectiveness of the proposed approach is ultimately verified using two distinct types of batteries across three operational temperatures. The results demonstrate that the proposed approach show much potential as a promising capacity estimation technique utilising a 600 s random charging segment sampled at a 20 s interval.

Study on controllability assessment of a new type of power system based on lagrangian function integrated assessment method

The complex structure and multiple controllability metrics of the new power system require a comprehensive assessment approach. We propose a controllability assessment method based on the Lagrangian function, analyzing key factors that influence controllability. Our index system includes distributed power supply utilization rate, energy storage station charge state, power factor, and voltage offset. Using Lagrange shadow price theory, we construct a guideline layer index system treating bottom indexes as constraints. We formulate an optimization function utilizing the Lagrangian shadow price theory and considering weights calculated from the bottom index’s shadow price. These weights inform primary evaluation. By combining primary evaluation results, weights, and variable coefficients using the percentage system method, we determine comprehensive evaluation results for the new power system’s controllability. Experimental results demonstrate the high reliability of this method’s evaluation indexes, indicating their effectiveness. This research provides valuable insight for the advancement of the new power system. Region 1 had the lowest overall evaluation score of 51.57 and was rated general. The overall score of Region 2 was 77.24, which was considered good. Region 3 received the highest overall score of 86.29 and was rated as excellent.Graphical

Effects of current collectors on the self-discharge rates of supercapacitors with aqueous electrolyte

Current collectors play an important role in supercapacitors, impacting not only their electrochemical properties such as rate performance and cycling stability but also their self-discharge processes. In this study, we investigate the self-discharge behaviors of activated carbon supercapacitors with various current collectors, including titanium (Ti) foil, nickel (Ni) foil, 316 stainless steel (SS) foil, and graphite paper (GP), in an aqueous electrolyte. Our findings reveal that at a relatively low charging voltage of 0.8 V, supercapacitors with different current collectors exhibit similar decays in open circuit voltages (OCVs) after 12 h, indicating comparable self-discharge rates. However, at higher charging voltages, SS-based supercapacitors exhibit significantly faster self-discharge compared to Ti, Ni, and GP. Particularly at 1.6 V, the 12-h voltage retention rates decrease from over 60 % for Ti, Ni, and GP supercapacitors, to 46 % for SS supercapacitors. Analysis of the self-discharge mechanism suggests that increased side Faradaic reactions occurring at higher charging voltages in SS-based supercapacitors contribute to the accelerated self-discharge process compared to Ti, Ni, and GP supercapacitors.

An improved wireless power transmission system for micro unmanned aerial vehicles

AbstractDue to its limited load capacity, the piggybacking of wireless charging systems for micro unmanned aerial vehicles has become a challenging task in the design of micro unmanned aerial vehicles. Therefore, this paper proposes an improved lightweight design method for micro unmanned aerial vehicles to carry a wireless charging system. The improved system uses an inductor–capacitor–capacitor‐parallel (LCC‐P) topology compensation network instead of a bilateral inductor–capacitor–capacitor (LCC) topology compensation network to achieve constant current charging (CC) and constant voltage charging (CV). Then the adaptive frequency conversion control is used to realize the automatic conversion from CC charging to CV charging during the charging process. Compared with the traditional wireless charging system based on a direct current‐direct current converter (DC‐DC converter) to achieve CC charging and CV charging, this improved system reduces the total weight of the receiving end of the wireless charging system based on ensuring the charging efficiency, which meets the demand of wireless charging systems carried by micro drone aircraft. The test results of the constructed physical system coincide with the simulation design results, and the total weight of the receiving end is only 8 g, which verifies the correctness and effectiveness of the improved design scheme.

A Formula to Customize Cathode Binder for Lithium Ion Battery

AbstractThe binder plays a crucial role in binding the solid electrode components and fixing them to the current collector, ensuring good contact and transformation. The high‐energy‐density cathode poses several challenges for the Polyvinylidene fluoride (PVDF) binder, such as high electrode potential, mass loading, and binding force. Although various new binders are proposed to optimize the electrochemical performance of cathode, the design focus and mechanisms often lack universality. This study introduces a design strategy for the cathode binder from the perspective of molecular structure design. The performance of the binder is optimized by adjusting the soft‐hard and hydrophilic‐hydrophobic balances of the polymer, and the effectiveness of this strategy is verified in the LiCoO2 (LCO) system. The optimized copolymer binder improves the cycling stability of the LCO electrode under high load and low binder content conditions and even achieves stable operation at a high charging voltage of 4.6 V. The mechanism for improving the performance of LCO electrodes is that the optimized binder stabilizes the electrode structure, the active material particle structure, and the active material interface. This design strategy provides a valuable reference for customizing cathode binders.

Highly efficient corrosion inhibitor for low charge voltage and long lifespan rechargeable aqueous zinc-air battery

Hydrogen evolution, passivation and dendrite growth problems faced by zinc anodes of aqueous zinc-air batteries greatly reduce their cycle life and hinder their application in energy storage devices. Herein, a reversible, corrosion-resistant, and long-term stable cycle-life zinc anode is achieved by introducing zinc acetate and zinc gluconate into an alkaline electrolyte as corrosion inhibitors. Zinc acetate adsorbed on the surface of the zinc anode could be able to regulate the anode/electrolyte interface and thus inhibit the growth of dendrites, and zinc gluconate can reduce the charge voltage on the cathode to regulate the oxidation reaction and then prolong the cycle life, which eventually inhibit zinc anode corrosion. The additive package of zinc acetate and zinc gluconate provides a better performance. With addition of corrosion inhibitors, Zn||Cu cells show a high average coulombic efficiency about 94 %, and zinc-air batteries achieve a cycling lifespan of 297 h and low charge voltage of 1.7 V. This work provides a simple but practical guideline for high-performance zinc-air batteries.

Microfluidic carbon cloth-based enzymatic glucose biofuel cell for sustainably powering a microelectronic circuit *

Enhancing enzymatic microfluidic biofuel cells (EBFCs) devices has garnered significant attention due to the development of microfluidic ultra-low power energy-gathering techniques. To facilitate the ability to create microfluidic EBFCs, a carbon cloth (CC) has been considered since they are effective renewable energy sources and utilized as the ideal paper-based substitute for traditional power supplies for a variety of tiny devices due to their inherent qualities and exceptional performance. The developed microfluidic EBFC utilized glucose as a fuel, carbon cloth as the bioelectrode, Glucose oxidase for the anode, and laccase for the cathode. The maximum stable open circuit voltage of CC-EBFC was measured to be 475 mV with a peak power density of 85 µW cm−2 at 300 mV and a current density of 484 µA cm−2. The power performance of the device was improved by bovine serum albumin and a booster circuit, which was also coated and connected to the load to stabilize the performance. The novelty of the work is that using a flexible substrate of carbon cloth, with a microfluidic channel, has an added advantage in the biofuel cell. LTC3108EDE DC–DC booster was used to increase energy and attain a high charging voltage of 5 V to operate a digital watch up to 3 V. With minimal weight and flexibility; this minuscule device opens up new possibilities to sustainably power wearable and portable microelectronic devices.

First-Principles Study of High-Entropy Sulfides and their Alkali Metal-Doped Modification as Cathode Material for Sodium-Ion Batteries.

High-entropy materials (HEMs) have been explored as high-capacity cathode materials for sodium-ion batteries (SIBs) due to their excellent structural stability and abundant metal redox sites. Among them, high-entropy sulfides (HESs) have greater potential and more extensive research than high-entropy oxides, as they exhibit higher charging voltage and theoretical capacity as cathodes. Furthermore, alkali metal doping of HESs can further enhance their performance and broaden their application fields. Inspired by the cocktail effect of HEMs, we performed the first theoretical calculation of the properties of Na(MnFeCoNi)1/2S and its Li-doped derivative, Na7/8Li1/8(MnFeCoNi)1/2S, to understand their potential as SIB cathode materials. Using density functional theory based on first principles, we investigated the structure and electronic characteristics of Na(MnFeCoNi)1/2S and Na7/8Li1/8(MnFeCoNi)1/2S, and calculated their theoretical voltage and capacity, respectively. Compared with Na(MnFeCoNi)1/2S, Na7/8Li1/8(MnFeCoNi)1/2S showed better electronic performance in reducing the band gap and increasing the density of states, ultimately providing a specific capacity of 160.3 mAh ⋅ g-1 and a charging voltage of 4.85 V in sodium-ion storage. Moreover, Na7/8Li1/8(MnFeCoNi)1/2S exhibited remarkable structural stability throughout the sodium-ion deintercalation process, thus it can be reasonably concluded that Na7/8Li1/8(MnFeCoNi)1/2S can serve as an excellent cathode material for future SIB applications.

High-Performance PM6:Y6-Based Ternary Solar Cells with Enhanced Open Circuit Voltage and Balanced Mobilities via Doping a Wide-Band-Gap Amorphous Acceptor.

Great progress has been made in organic solar cells (OSCs) in recent years, especially after the report of the highly efficient small-molecule electron acceptor Y6. However, the relatively low open circuit voltage (VOC) and unbalanced charge mobilities remain two issues that need to be resolved for further improvement in the performance of OSCs. Herein, a wide-band-gap amorphous acceptor IO-4Cl, which possessed a shallower lowest unoccupied molecular orbital (LUMO) energy level than Y6, was introduced into the PM6:Y6 binary system to construct a ternary device. The mechanism study revealed that the introduced IO-4Cl was alloyed with Y6 to prevent the overaggregation of Y6 and offer dual channels for effective hole transportation, resulting in balanced hole and electron mobilities. Taking these advantages, an enhanced VOC of 0.894 V and an improved fill factor of 75.58% were achieved in the optimized PM6:Y6:IO-4Cl-based ternary device, yielding a promising power conversion efficiency (PCE) of 17.49%, which surpassed the 16.72% efficiency of the PM6:Y6 binary device. This work provides an alternative solution to balance the charge mobilities of PM6:Y6-based devices by incorporating an amorphous high-performance LUMO A-D-A small molecule as the third compound.

10 kV nanosecond pulse generator with high voltage gain and reduced switches

AbstractIn the article, a new type boost high‐voltage nanosecond pulse generator is proposed. The distributed inductance of the transmission line is utilised as the energy storage unit and cooperated with the variable impedance transmission line transformer to generate nanosecond pulses with extremely high‐voltage gain. What’s more, the isolation effect caused by the transmission line time delay is applied to achieve modular stacking. The demand for charging power supply can be greatly reduced, and few switches are used. Finally, the topological principle is verified by experiments, and a prototype of the five‐stage stacking prototype is built. With the charging voltage of 28 V, the generator can output pulse with a voltage amplitude of 10 kV and pulse width of 12 ns whose voltage gain is up to 357 times.

Compact hard x-ray flash radiography device based on wire-shorted low-impedance rod pinch diode.

A rod pinch diode (RPD) is a feasible load configuration to generate a high-brightness, small-size hard x-ray radiation source. In this paper, the radiography performance of a wire-shorted low-impedance RPD on a compactly designed table-top driver (WRPD-1) is demonstrated for the first time. The driver consists of four high-power discharge branches connected in parallel, with each branch consisting of two metal-film capacitors and one multigap field-distortion switch in series. The four branches are triggered synchronously to generate a fast-rising current pulse: the inductance of the load section at the short circuit is ∼10 nH, and the short-circuit current amplitude is ∼325kA at ±90kV charging voltage, with a 10%-90% rise time of 110ns. With a low-impedance RPD shorted by an 18-µm-diameter aluminum wire, a quasi-spherical x-ray focal spot with diameter <0.6mm (width of the half-maximum grayscale) and a pulse duration of ∼25ns (half-width of the radiation pulse) is obtained at ±70kV charging voltage, and the imaging resolution excels 10 lp/mm under 1.56× magnification. According to the transmission-absorption x-ray spectrum estimation, the average emitted photon energy is ∼30keV with a distinct peak in the 10-15keV range that corresponds to the L-lines of tungsten, and the total energy of photons >10keV reaches ∼1.16J. The present results show that the device can serve well for the flash radiography diagnosis and potentially as an efficient light source for dynamic x-ray diffraction.

Long-Cycle Lithium Batteries with LiNi0.8Co0.1Mn0.1O2 Cathodes above 4.5V Enabled by Uniform Coating of Nanosized Garnet Electrolytes

Abstract The pursuit of high-energy cathode materials has been focused on raising the charging cutoff voltage of nickel (Ni)-rich layered oxide cathode such as LiNi0.8Co0.1Mn0.1O2 (NCM811). However, the NCM811 suffers from rapid capacity fading upon cycling at cutoff voltage higher than 4.5 V, owing to their structural degradation and labile surface reactivity. Surface-coating with solid electrolytes has been recognized as an effective method to mitigate the performance failure of NCM811 at high voltage. Herein, the nano-sized Li6.4La3Ta0.6Zr1.4O12 (LLZTO) is uniformly coated on the surface of single-crystal NCM811 particles, accompanied with the long-range Ta5+ diffusion into the transition metal layer of NCM811 lattice. It is revealed that the LLZTO coating can not only inhibit the surface reactions of NCM811 with liquid electrolytes but also play an important role in suppressing the bulk microcracking within the NCM811 particles. The incorporation of Ta5+ ion expands the lattice spacing and thereby improves the homogeneity of the Li+ diffusion in the single-crystal NCM811, which alleviates the mechanical strain and intragranular cracks caused by nonuniform phases-transformation at high charging voltage. The synergy of surface protection and structural stabilization realized by LLZTO coating enables the NCM811-based lithium batteries to achieve a remarkable electrochemical performance. Typically, LLZTO coated NCM811 delivers a high reversible specific capacity of 202.1 mAh⋅g−1 with an excellent capacity retention as high as 70% over 1000 cycles upon charging to 4.5 V at 1 C.

Rancang Bangun Pengisian Tegangan Baterai Handphone (HP) Metoda Buck Konverter DC-DC Tipe FC75

Mobile phone (HP) battery manufacturing specifications have a charging current capacity maximum parameter CAh(maks.) = 800 mAh and maximum voltage Vbat(max.) = 3.7 volts dc reduces to 2.02 volts dc requires recharging. In this research HP battery voltage was recharged using the FC75 dc-dc buck converter method, starting from a voltage of Vbat(initial) = 2.02 volts until the final battery voltage was charged at Vbat(final) = 3.713 volts. The HP battery charge voltage parameter Vch comes from the output voltage of the FC75 dc-dc buck converter the parameter Vo(conv.) is expressed as Vo(conv.) = Vch. The purpose of using the FC75 dc-dc buck converter is to electronically convert the lower Vo(conv.) charger voltage (buck) to the larger Vi(conv.) input voltage to control the HP battery charger output power equal to the input power. The results of the research on controlling the output power of the HP battery charger of Po(conv.) = Pi(conv.) = 0.579 watts, there was an increase in the final charger voltage Vokonv.(final) along with the increase in the final HP battery voltage Vbat(final) being charged. The increase in the final charger voltage reaches Vokonv.(final) = Vbat(final) = 3.713 volts, the final charger current becomes Ich(final) = 0.156 A and remains towards the HP battery during charging with a difference in the decrease in charger current towards the HP battery of ∆Ich = 0.009 A relatively small is still profitable, because it avoids back current to the charger voltage.

Research on topology technology of integrated battery energy storage system with reconfigurable battery and converter

In traditional battery energy storage systems (BESS), batteries are usually connected in a simple series or parallel form, and separate converters and balancing modules are typically used for energy exchange between the battery and external sources, as well as for balancing energy between batteries. This paper proposes an integrated battery energy storage system (IBESS) with reconfigurable batteries and DC/DC converters, resulting in a more compact structure. The IBESS can reconfigure the connection of energy storage batteries based on the battery's status and external demand. The DC/DC converters can operate in different modes such as boost, buck, or buck-boost converters. The IBESS has five working modes: discharging mode, balancing mode, battery discharging and balancing mode, constant current and constant voltage (CCCV) charging mode and backup mode. To verify the feasibility of the proposed energy storage system, a model with four battery modules was built using MATLAB/SIMULINK, and the operation of all working modes was demonstrated. The simulation results verified the system's performance and reliability, demonstrating its flexibility and efficiency in different operating modes.

Test of a YBCO thin film based over current limiter employed in battery unit of SMES-battery HESS during charging process

This paper proposes a novel over current protection strategy based on YBa2Cu3O7-x (YBCO) thin film current limiter, to improve the over current stability of the battery unit in superconducting magnetic energy storage (SMES)-battery hybrid energy storage system (HESS) during charging process. The conventional over current protection strategy for battery unit is based on cutting off the operation of the battery unit to remove the fault. Especially, during the charging process, once the battery unit circuit is cut off, the stability and reliability of the HESS will be also reduced. Hence, considering the features of the YBCO thin film in both superconducting state and quench state, it can be deployed as the over current limiter, to keep the stability of the battery unit against the over current fault during the charging process. In this paper, we designed and fabricated the YBCO thin film over current limiter, meanwhile, the preliminary verification experiment was carried out in our laboratory. It can be found from the experimental results that the over current in battery unit can be limited effectively by its quench resistance without cutting off the whole circuit. Besides, the charge voltage fluctuation of the battery unit can be also compensated by using the proposed protection strategy. Thus, the stability and reliability of the battery unit against the over current fault in charging process can be further improved.

Self-powered synchronous asymmetric voltage flip and charge extraction technique for piezoelectric energy harvesting

Abstract This paper presents a nonlinear interface circuit for piezoelectric vibration energy harvester (PEH) with Synchronous Asymmetric Voltage Flipping and Charge Extraction process, denoted as SAFCE. SAFCE flips the PEH voltage polarity at positive peak and completely extracting charge at negative peak through LC resonance. The harvested power is independent of load. In theory, the harvested power is 200 % of SECE and 780 % of best impedance-matched SEH due to the energy injection mechanism, which enhances the electromechanical coupling coefficient of PEH. Moreover, a self-powered SAFCE circuit without rectifier bridge is designed, which reduces power consumption and eliminates the need for external power sources. Experimental measurements are carried out to compare with SEH and SECE circuits under the condition of either constant displacement magnitude (0.5 mm) or constant external excitation acceleration (10 m/s2). The experimental results indicate that the power harvested by the SAFCE technique increased by 171 % compared with the SECE method and by 381 % compared with the best impedance-matched SEH method under the same conditions.

A Light-Load Efficiency Improvement Technique for an Inductive Power Transfer System through a Reconfigurable Circuit

Constant voltage (CV) charging and efficiency improvement are the most basic and main targets to be achieved in inductive power transfer (IPT) systems. However, efficiency may be jeopardized as battery charging progresses, especially under a light-load condition, which accounts for most of the charging time. Traditional maximum-efficiency tracking (MET) control provides an effective solution to the above issues. However, MET control not only brings the difficulties of complicated control and increased cost/volume, but also increases the additional power losses because of the introduction of additional converters or hard-switching in dual-shift phase control. To address the above difficulty, a light-load efficiency improvement (LLEI) technique is presented in this study. Under a heavy-load condition, both the inverter and rectifier operate in conventional full-bridge mode with satisfactory efficiency. Under a light-load condition, both the rectifier and inverter are reconfigured as a voltage-doubler rectifier and half-bridge inverter, respectively, to achieve two targets: one is to keep the charging voltage roughly unchanged, and the other is to force the equivalent load resistance (ELR) approach to the optimal point to improve system power transfer efficiency. A demonstrative experimental prototype with a charging voltage of 60 V is constructed and tested to validate the LLEI method proposed in this study. The experimental results show that the proposal can ensure stable CV charging and significantly improve the system efficiency under a light-load condition over the whole charging process.

Experiment-Based Determination of Optimal Parameters in Constant Temperature–Constant Voltage Charging Technique for Lithium-Ion Batteries Using Taguchi Method

Charging methods significantly affect the performance and lifespan of lithium-ion batteries. Investigating charging techniques is crucial for optimizing the charging time, charging efficiency, and cycle life of the battery cells. This study introduces a real-time charging monitoring platform based on LabVIEW, enabling observation of battery parameters such as voltage, current, and temperature. The proposed system allows the precise control of charging parameters via a user-friendly interface. Utilizing a programmable DC power supply, it delivers specific charging waveforms, while data acquisition instruments record temperature changes. Key performance metrics, including charging time, efficiency, and temperature rise, are analyzed. Moreover, this paper conducts in-depth research on the constant temperature–constant voltage (CT-CV) charging technique and applies the Taguchi method to identify key parameter configurations that achieve the objectives of the shortest charging time, highest charging efficiency, and lowest average temperature rise. A comprehensive evaluation compares the optimized CT-CV method with conventional constant current–constant voltage (CC-CV) charging. The results demonstrate a 10.7% reduction in charging time compared to the 1C CC-CV method, indicating the efficacy of CT-CV in shortening charging duration while managing temperature rise.