Equal Charge Research Articles

An Analytic Hierarchy Process for Selecting Battery Equalization Methods

Batteries have been the predominant energy storage system used in electric vehicles. Battery packs have a large number of cells that develop charge, thermal, and capacity imbalances over time, limiting the power, range, and lifetime. Electronic battery management and state of charge (SoC) equalization methods are necessary to mitigate such imbalances. Today, it is possible to find a wide range of battery equalization methods in the literature, but how to decide which of these methods should be applied in practice? This paper compares 24 SoC equalization circuits that are typically found in automotive applications. We employ an analytic hierarchy process (AHP) approach to rank these equalization circuits according to multiple decision criteria (energy efficiency, equalization speed, implementation and control simplicity, hardware size, and total price). We also prepared a survey to collect design preferences from multiple battery balancing experts from around the world in order to better understand the relative importance of different criteria. The obtained results confirm that automotive engineers continue to favor passive balancing methods because of their low price, small PCB size, and implementation simplicity—despite the energy efficiency benefits of active balancing.

An integrated equalization charger for series‐connected energy storage cells

SummaryThis paper proposes an integrated equalization charger that integrates the charger, module‐level equalizer, and cell‐level equalizer into the energy storage system, which greatly simplifies the system. The proposed control strategy can not only improve the equalization charging characteristics of the system, such as fast balancing speed and high efficiency, but also enable all active switches to achieve zero voltage switching (ZVS) operation. The established analytical models and control block diagram facilitate the design and development of the converter. The proposed converter can balance the cells while charging the string. An experimental prototype was developed, and the experimental results verified the theoretical analysis and demonstrated the characteristics of the proposed converter.

Highly selective isoporous block copolymer membranes with tunable polyelectrolyte brushes in soft nanochannels

We used partial crosslinking of the pore-forming block of quaternized PS- b -P4VP integral asymmetric isoporous membranes as a tool to control the effective pore size in aqueous and alcoholic media. A versatile top-down membrane post-modification approach using a combination of difunctional and monofunctional alkyl halide was employed to obtain well-defined nanochannels containing polyelectrolyte brushes. Mild and scalable gas-solid reactions were used for the membrane post-modification. The permeance of the modified membranes changed systematically over a wide range, proving the potential of using the membrane post-modification technique to tailor the pore size from ultrafiltration to nanofiltration regime. Using a membrane post-modification technique, for the first time a series of integral asymmetric isoporous membranes having equal charge density but distinct effective pore size was successfully prepared. The separation performance based on size and charge is demonstrated by separating 1–2 nm organic molecules (having molecular weights in the range of 248–480 g mol −1 ) with excellent selectivity and permeance. For example, one of the prepared membranes showed a 2.4 times higher retention of methylene blue (MB+, 319.85 g mol −1 ) than chrysoidine G (CG+, 248.71 g mol −1 ) from an aqueous feed solution containing equimolar MB+ and CG + while the permeance was 134 Lm −2 h −1 bar −1 . • Fabricated scalable, positively charged isoporous block copolymer membranes. • Tuned polyelectrolyte brushes within soft nanochannels. • Systematically tailored membrane pore size in aqueous and alcoholic media. • Separated 1–2 nm organic molecules with high selectivity and permeability. • Demonstrated the great potential of isoporous membranes for molecular separation.

Experimental Synthesis of Theoretically Predicted Multivalent Ternary Nitride Materials

Multivalent ternary nitride materials, which combine two metal cations with a nitrogen anion in equal amounts and charge balanced stoichiometry, tend to have relatively simple structures and promising properties for a broad range of applications. Historically, discovery of such new nitrides has been a bulk synthesis endeavor, following chemical intuition. In the past decade experimental synthesis of theoretically predicted materials, including as thin films, has changed this approach. In this perspective, we discuss progress in the experimental synthesis of theoretically predicted multivalent ternary nitrides, with the focus on Zn- and Mg-based materials. First-principles theoretical calculations predicted structures and properties of many new Zn–M–N and Mg–M–N materials and offered insights into the effects of cation ordering. Thin film and bulk experiments were used to synthesize some of these predicted multivalent ternary nitride compounds such as Zn3MoN4, Zn2SbN3, and Zn2NbN3, as well as MgZrN2, Mg2NbN3, and Mg2SbN3, and many others. These multivalent ternary nitride success stories should inspire experimental synthesis of other underexplored materials predicted by theoretical calculations.

Efimovian states of three charged particles

When three particles in three dimensions interact with a short-range potential fine-tuned to an infinite scattering length, they form an infinite sequence of loosely bound states obeying discrete scale invariance known as Efimov states. Here we show that analogous states are formed by three charged particles carrying two equal charges and one opposite charge in one, two, and three dimensions without any fine-tuning. Our finding is based on the Born-Oppenheimer approximation, where an effective inverse-square attraction is induced as a consequence of the dipole-charge interaction between a hydrogenlike heavy-light atom and a far-separated heavy particle. Because the resulting Efimovian states emerge toward the second or higher dissociation threshold, they are to be realized as quasibound states and may be observed by exciting hydrogen molecular ions and trions in excitonic systems. We also consider the same system but with a logarithmic Coulomb potential relevant to quantum vortices in two-dimensional superfluids, where the Efimovian states are shown to emerge as genuine bound states toward the first dissociation threshold.

Modelling and Control of Ultra Capacitor-Based High-Gain DC–DC Converter System with Charge Equalization Circuits

Modelling and Control of Ultra Capacitor-Based High-Gain DC–DC Converter System with Charge Equalization Circuits

Charge-Controller Optimization on Lead-Acid Battery in Solar PV Systems: Temperature Effects and Efficiency Improvement

Long-term cell performance is very sensitive to the cell operating temperature, and cell storage capacity can degrade quickly, if the temperature is not maintained within a narrow range (25–50 °C) during charging and discharging of (solar) batteries [1]. Efforts are recently being dedicated to developing models that seek to provide insights into that issue. However, not all models consider the operation of the photovoltaic (PV) battery storage system with regard to battery optimization and temperature effects. The present work provides a controllable algorithm to help charge controllers provide exact amount of PV electricity (charge equalization) to batteries with temperature compensation included, and a proposed charging and discharging schedules of the battery storage. The temperature compensated duty cycle for charging is modelled and the pulse-width modulation (PWM) signal is programmed to change with temperature following this duty cycle model. This research work is based on the optimization of solar battery storage where the micro controller-based charge controller enhances battery life by monitoring the temperature and controlling charging voltages and float charging voltages for specific temperatures. A buck converter was simulated in Proteus, and then realized in the laboratory. The duty cycle of the buck converter was adjusted with temperature. Results collected from lab experiments were plotted on MatLab and it shows homogeneity with calculated results. Moreover, battery-charging currents, battery direct current (DC) disconnect and battery switching for charging and discharging were performed for the converter. Future work is to extend this study to large-scale solar photovoltaic systems in order to overcome the operation limits encountered.

Basicity of isostructural porous ionic crystals composed of Nb/Ta-substituted Keggin-type polyoxotungstates

Three isostructural porous ionic crystals (PICs) based on Keggin-type POMs with different compositions but equal negative charge ([BW12O40]5−, [SiW11NbO40]5−, and [SiW11TaO40]5− ) are synthesized.

On the Relationship between Quarks and Electrons

In this study, the relationship between the elementary masses and elementary charges of quarks and electrons is considered in connection to the strong nuclear force and the color charge. The relationship is further considered in connection with the matter-antimatter asymmetry problem, and the decay times for different particles. The results strongly suggest that the quarks can be expressed as charge equalization of the electron, and that the coincidence of the charges has no alternative way to be unified with the elementary masses. To solve these problems, a new standard model with a second group of antiparticles is proposed, and the strong nuclear force is considered as an interaction between equalized electric charges instead of being a fundamental force, which also explains its short-ranged high strength. A new periodic table of elements is proposed to unfold the overall number of elementary charges that make up the atomic nucleus of different elements.

Charge equalisation of electric vehicle battery system using intelligent controller

Exhaust emissions from conventional vehicles adversely affect the environmental balance, thereby an enhanced adoption of electric vehicles (EVs) is required. Among the existing energy storage systems, rechargeable batteries, especially Li-ion battery, play a major role in the commercialisation of EVs due to its long cycle life, high energy and power density and low self-discharge. A novel state of charge (SOC) based modular cell balancing equaliser (CBE) scheme integrated with intelligent control techniques is proposed. The performance of CBE is analysed based on the simulation works done under Simulink MATLAB environment with series-connected modular Li-ion battery. The bidirectional non-dissipative CBE structure is combined with intelligent controller to balance the voltage among the cells considering the effect of SOC of each individual cell. The proposed balancing circuit and control method improve the speed of balancing accuracy without exceeding the upper voltage limit as evident from the simulation results.

Charge equalisation of electric vehicle battery system using intelligent controller

Charge equalisation of electric vehicle battery system using intelligent controller

Battery Management System Performance Enhancement using Single Sliding Mode Based Charge Equalization Controller

In this paper, the study aims to evolve a precision model of a Battery charge equalization controller (BCEC) that manage each cell of a lithium-ion (Li-ion) battery, monitoring a nd balancing by charging a nd discharging a series-connected Li-ion battery with several cells (n) in electric vehicle (E.V.) applications. An intelligent Sliding mode controller is evolved to activate bidirectional cell switches and regulate a chopper circuit’s direct current (DC-DC flyback converter circuit) with PWM generation. To implement a small-scale BCEC, the model consists of individual models of an E.V., cells of Li-ion battery, a fly-back converter, and a single sliding mode controller (SSMC) for charging and discharging are integrated with n series-connected cells of Li-ion-battery. The BCEC output shows that the cells are operated within a safe range, and the difference in the state of charge (SOC) is maintained to be 0.1%. Comparing the developed BCEC with the existing controllers, with the performance, control algorithm, efficiency, power loss, size, and cost.

A novel nine‐level boost inverter with a low component count for electric vehicle applications

In electric vehicles (EVs), considerable battery cells are cascaded in series for motor driving to improve the output voltage. The series combination of battery cells causes challenges like isolation of faulty cells, voltage unbalance, and slow charge equalization. Therefore, state-of-charge (SOC) and voltage equalization circuits are often used in industries to protect the battery cells. A nine-level inverter circuit with a double voltage boost is proposed to reduce the above issues based on the switch-capacitor (SC) principle. Unique features like self-balancing, voltage boosting are attained, which cannot be achieved through traditional inverters. The proposed topology can operate at a wide range of modulation indices () to produce different voltage levels. The absence of a back-end H-bridge in the proposed circuit offers low voltage stress across the semiconductors. The operating principle, capacitor sizing, and modulation approach are presented. Further, experimental tests are conducted at different loading conditions to verify the performance of the proposed circuit.

INTRODUCING GAP IN HAIR FOLLICLE ELECTROMAGNETISM AS MECHANISM FOR THE PRESENCE OF BIPOLAR ELECTRICAL CHARGES INHERENT IN THE HUMAN HAIR SHAFT

The human hair consists of a follicle anchored in the skin and a protruding shaft, it has also been described as a miniorgan, having its own cell divisions, metabolism, and known to undergo aging stages; eventually reaching a point where the old hair sheds and a new hair growing cycle begins from the same follicular tissue. Using sophisticated magnetometers, magnetic field emitted by direct current (DC) in human hair follicles were detected and introduced in 1980. Most recently in 2015, a tabletop optical microscopy method was developed and published in 2016, thus allowing for the detection of hair follicles and shaft magnetic fields. Qualitative images are presented where the bipolar electrical property of the shaft is documented. This finding was inferred since blood tissue carries a negative charge, thus repelled by an equal charge; experiments support a positive (+) field as triggering coagulation. The shaft is repeatedly shown in experiments to express a contralateral positive side triggering. Fibrin formation is also documented by images showing intricate networks indicative of blood coagulation. In conclusion, the genesis of hair shafts bipolarity is shown resulting from a “gap” in the follicle electromagnetic fields inhibiting energy from fully engulfing the shaft.

Femtosecond laser direct writing continuous phase vortex gratings with proportionally distributed diffraction energy

In this Letter, we propose a type of continuous phase vortex gratings (CPVGs), which are able to generate a series of vortex beams with equal or proportional diffracted energies and different topological charges (TCs). A set of CPVGs with dimensions (60 × 60 × 1.1 μm3) are directly designed by mathematical equations, which avoids the use of iterative algorithms. The CPVGs are fabricated by femtosecond laser direct writing (FsLDW) with photoresist, and the experimentally generated vortex beams are in good agreement with the theoretical designs, exhibiting high optical efficiencies. In addition, we realized a CPVG onto the tip of a composite fiber for integrated optical systems. Our work paves the way for applications in optical communications, optical manipulations, and high-performance integrated optics.

Diffusive properties of colloidal charged particles in a quasi-one-dimensional confinement

Diffusive properties of colloidal crystals in a quasi-one-dimensional channel are studied using numerical simulations. In order to study the influence of the attractive interaction between particles, it was introduced as an artificial dimensionless parameter β in the attractive term of the interaction potential. Changing the value of β, we can tune the effect of attraction between particles. We show that charged particles can change their mobility and the diffusion exponent of a one-chain like system. Variation on exponent diffusion can be induced by tuning the attractive part of interaction potential, making possible the existence of diffusive regimes between single-file diffusion (SFD) and normal diffusion, without changing confinement strength. System stoichiometry was changed, imposing particles in different arrangements in small clusters, which varies the diffusive behaviour. If stoichiometry is different from 1:1, it is possible to have particles with equal charges but with different mobilities. Another important observation is that mean-square displacement (MSD) for different charges is different for different values.

Equalization Charging Technology for Battery Pack - Study Based on State Variable Theory Approach

Equalization Charging Technology for Battery Pack - Study Based on State Variable Theory Approach

Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu2+ ions

This work studies the impact of the electrostatic interaction between analyte molecules and silver nanoparticles (Ag NPs) on the intensity of surface-enhanced Raman scattering (SERS). For this, we fabricated nanostructured plasmonic films by immobilization of Ag NPs on glass plates and functionalized them by a set of differently charged hydrophilic thiols (sodium 2-mercaptoethyl sulfonate, mercaptopropionic acid, 2-mercaptoethanol, 2-(dimethylamino)ethanethiol hydrochloride, and thiocholine) to vary the surface charge of the SERS substrate. We used two oppositely charged porphyrins, cationic copper(II) tetrakis(4-N-methylpyridyl) porphine (CuTMpyP4) and anionic copper(II) 5,10,15,20-tetrakis(4-sulfonatophenyl)porphine (CuTSPP4), with equal charge value and similar structure as model analytes to probe the SERS signal. Our results indicate that the SERS spectrum intensity strongly, up to complete signal disappearance, correlates with the surface charge of the substrate, which tends to be negative. Using the data obtained and our model SERS system, we analyzed the modification of the Ag surface by different reagents (lithium chloride, polyethylenimine, polyhexamethylene guanidine, and multicharged metal ions). Finally, all those surface modifications were tested using a negatively charged oligonucleotide labeled with Black Hole Quencher dye. Only the addition of copper ions into the analyte solution yielded a good SERS signal. Considering the strong interaction of copper ions with the oligonucleotide molecules, we suppose that inversion of the analyte charge played a key role in this case, instead of a change of charge of the substrate surface. Changing the charge of analytes could be a promising way to get clear SERS spectra of negatively charged molecules on Ag SERS-active supports.

Research on Alternating Equalization Control Systems for Lithium-Ion Cells Charging

Lithium-ion batteries which are used in electric vehicles cannot be charged to their maximum capacity at the end of the charging period, a situation which is caused by inconsistency between the battery cells. This paper takes the 18650 ternary lithium battery as the research object and proposes an alternate equalization control system in the charging process. This system takes SOC consistency to be the equalization variable. Through controlling the relay, this system realizes the alternate recombination between different batteries in order to form a series battery group for charging, which achieves the goal of SOC equalization of the entire battery group. The simulation result of charge equalization, based on Matlab/Simulink, shows that at the end of the charging simulation, the SOC inconsistency of the battery group reduced from 10% to 1%. Finally, an experimental platform was built in order to verify the experiment. During the charge balance experiment, the maximum SOC inconsistency between the batteries reduced from 1.542% to 1.035%. The SOC inconsistency at the end of charging reduced from 1.214% to 0.8%, which represents an improvement of the equalization effect of the control system. The experimental results are consistent with the simulation results, which proves the effectiveness of the system’s ability to control the battery SOC balance during the charging process.

Nonadiabatic localization of H2 in the field of two external positive tip charges

For two external spherical tips with equal positive charges, the ground state of a hydrogen molecule is variationally determined within the quantum Monte Carlo scheme. For finiteness, the system is enclosed in a spherical container with randomly reflecting unstructured walls. The 12-dimensional system of two protons and two electrons is investigated ab initio without any adiabatic restrictions. We focus on the hydrogen center of mass (COM) distribution in continuation of previous work on ground state and vibration modes at a COM that was fixed in space. Our general purpose is to control the molecule’s position and orientation by external means, such as by two charged tips. To this end, knowledge is needed in order to find specific COM regions with a desired molecular orientation in the container at significant probability density of the molecule.