Charge Pulse Research Articles

Pulsed Charging Protocols with Non-Zero Relaxation Time for Lithium-Ion Batteries

Lithium-ion batteries are commonly charged following the constant current -constant voltage (CC-CV) protocol. Current flow during charging implies an equivalent ionic flow through the battery materials. Intercalation and de-intercalation of Li+ are accompanied by concentration gradients that are reflected by the rise in the cells’ potentials that is required to maintain the constant current during the CC regime. In this work, two new pulsed charging protocols were tested. Firstly, a square current pulse is applied to the cell until the cut-off voltage is reached, followed by a pulsed square voltage protocol (PV). The second methodology keeps the same current pulse, however, after the limiting voltage was reached, the pulsing regime consisted in alternating between a maximum voltage value and a minimum, non-zero, constant current value. Different voltage pulse widths and frequencies were tested, in order to study the maximum electrodes’ capacity, the time required to reach that capacity, the contribution of each individual step (i.e. PC and PV) to the total electrodes’ capacity, and the thermal variations for each. The second pulsing mode produced capacity values 7%–8% higher than in the classical CC–CV protocol, and in charging times periods from 5%–25% faster, without compromising the batteries’ cycle life.

A readout electronic system for a 3D position-sensitive CdZnTe gamma-ray spectrometer based on the CPRE10-32 readout ASIC

A readout electronic system based on the Charge Pulse Readout Electronics 10-32 (CPRE10-32) Application Specific Integrated Circuit (ASIC) has been developed for the 3D position-sensitive CdZnTe gamma-ray spectrometer. The system includes the Font-end Electrics (FEE) board, the Data Acquisition (DAQ) board, the FPGA firmware, and the PC software. The Full Width at Half Maximum (FWHM) of the electronic noise of the system was approximately 4.72 keV when the 3D-CZT detector and high voltage were connected and the minimum gain was selected. The electronic noise at the minimum and maximum gain using the calibration signal without the detector was approximately 3.335 keV and 3.074 keV, respectively. The Equivalent Noise Charge Number (ENN) was about 375 e- with the detector and about 265 e- with the detector. The test data of Cs-137 demonstrated that the linear response range of the system reached up to 3 MeV and 450 keV at the minimum and maximum gain, respectively. With the 3D-CZT detector, the Am-241 and Cs-137 radioactive sources were detected, and the energy resolution was 7.25% and 2.22%, respectively. By performing electron drift time correction, the energy resolution of the full-energy peak of Cs-137 at 662 keV was improved to 0.76% at medium gain. After acquiring energy and time data successfully, it is demonstrated that this readout electronic system can meet the hardware requirements for Compton scatter imaging with 3D-CZT.

Switching waveform design with gate charge control for power MOSFETs

• Active gate driver has been used to mitigate trade-off between EMI noise and loss. • A novel method to obtain gate waveform from designed switching waveform is proposed. • The gate waveform is computed based on voltage/current response to gate charge pulse. • Switching waveform driven by the obtained gate waveform is verified in simulation. • The method can change slope of switching transition to mitigate the trade-off. Circuit diagram of the system based on the proposed method. The switching waveform design, especially controlling and optimizing the slew rate, is an efficient technique to mitigate the trade-off between decreasing the loss and increasing the noise of the switching power device. The digital active gate driver which generates the gate waveform to achieve the designed switching waveform requires a significant computational burden because the optimum driving point is searched automatically and comprehensively. This paper proposes a novel and simple method to calculate gate waveforms to achieve the designed switching waveforms. This method calculates how much gate charge is additionally required to match the designed waveform by exploiting the voltage and current response of the power device to the small gate charge pulse. The validation of this method is demonstrated by simulation in the case of both the drain-source voltage design and the drain current design. The deviation from the designed waveform is quantified in this paper.

Effects of Fast Charging Modes on Thermal Performance of Lithium‐Ion Battery

Fast charging technology can greatly increase the charging speed and shorten the charging time of electric vehicles, but the heat generation and temperature rise of the lithium‐ion battery during the fast charging process seriously affect its electrochemical characteristics and cycle life and even cause safety issues. Therefore, it is necessary to analyze the thermal performance of the lithium‐ion battery under fast charging conditions and investigate the effects of different fast charging modes on it. Herein, an NMC lithium‐ion cell is taken as the object, and the electrochemical–thermal coupling model is built and verified. Based on this model, the heat generations and temperature rises of the cell in different fast charging modes are analyzed and compared, including constant current (CC) charging, constant voltage (CV) charging, CC–CV charging, stage CC charging, and pulse charging. It is found that the peak temperature of the cell appears at different moments in the above charging modes. The peak temperature and total heat generation during CV charging are much greater than those during charging of other modes. The results can provide references for the design and selection of charging modes and battery thermal management systems toward fast charging technology.

Magnetic and electric antennas synergy for partial discharge measurements in gas-insulated substations: Power flow and reflection suppression

One of the main difficulties in measuring partial discharges (PD) in gas-insulated substations (GIS) is the overlapping of pulses at the sensor’s location, which distorts the pulse resolution and the charge estimation. This research presents a new method called “synergy,” which identifies and suppresses reflections using magnetic and electric antennas in the very-high frequency range. By scaling the antennas’ outputs and adding them, it is possible to segregate forward and backward pulses. Additionally, by multiplying the electric and magnetic signals, the power flow of the pulses is obtained, which identifies the propagation direction and the location of discontinuities in the transmission path. The synergy method is evaluated in three scenarios: a fully matched test bench using a calibrated pulse, a full-scale GIS using a calibrated pulse, and a full-scale GIS using a PD defect. The results showed that the pulse reflections can be eliminated from the incident pulse, improving the charge calculation when the pulses overlap. The output of this research represents an improvement for PD monitoring in GIS, exhibiting a tool for better defect localization, pulse wave shape construction, charge estimation, and possible interference rejection.© 2017 Elsevier Inc. All rights reserved.

Post-forming, electro-plastic effect internal stress reduction in AA5754 aluminium alloy

Aluminium alloys are one of the most efficient materials for weight reduction in the car industry. However, the favourable performance of alloys conflicts with the difficulties of transforming these materials through plastic deformation processes such as stamping. Among the different issues, they are characterised by a high springback effect. Numerous authors have explored the use of the electro-plastic effect (EPE) to mitigate internal stresses and the resultant springback. However, up-scaling existing laboratory solutions to an industrial framework is a critical challenge. Therefore, in this work, the post-forming electro-plastic effect (PFEPE) is explored in AA5754 material. Stress-relaxation + PFEPE experiments were conducted using different electric pulse charge passing though the sample, and, apart from the impact on residual stresses, the potential occurrence of recrystallisation was evaluated. The results indicate that a range of pulses exists (>2000 A·ms/mm2 and <4500 A ms/mm2) in which a 10–30% reduction in stresses can be achieved without critically impacting the material's mechanical performance.

Cover Feature: Desorption of Hydrogen from Graphene Induced by Charge Injection (ChemElectroChem 16/2022)

The Cover Feature shows the desorption of hydrogen from graphene in contact with an aqueous solution induced by a small positive charge pulse. From left to right: adsorbed hydrogen, transition state, hydronium ion, Grotthus step. More information can be found in the Research Article by W. Schmickler and E. Santos.

Desorption of Hydrogen from Graphene Induced by Charge Injection

AbstractHydrogen adsorbed on a graphene electrode in contact with an aqueous solution is in a metastable state. Here, its desorption induced by a small positive charge pulse was studied by molecular dynamics with a tight binding method based on density functional theory. The efficiency of the code allowed to follow the trajectory of the desorbed particle in detail. Desorption was triggered by an oxygen atom of water, which was attracted to the surface and approached the adsorbed hydrogen. Charge transfer occured, and the hydrogen was attached to the water molecule to form a hydronium ion, which drifted into the solution, changed its solvation and underwent Grotthus steps. The reverse process, adsorption of a proton from the solution, required a pulse with a high negative charge. The reaction was governed by the field right in front of the electrode, and not by the electrode potential. The time that the proton transfer takes is much shorter than the relaxation time of the double layer, so that simulations performed with a constant electrode potential may not be realistic.

Model-based pulse pileup and charge sharing compensation for photon counting detectors: A simulation study.

PurposeWe aim at developing a model‐based algorithm that compensates for the effect of both pulse pileup (PP) and charge sharing (CS) and evaluates the performance using computer simulations.MethodsThe proposed PCP algorithm for PP and CS compensation uses cascaded models for CS and PP we previously developed, maximizes Poisson log‐likelihood, and uses an efficient three‐step exhaustive search. For comparison, we also developed an LCP algorithm that combines models for a loss of counts (LCs) and CS. Two types of computer simulations, slab‐ and computed tomography (CT)‐based, were performed to assess the performance of both PCP and LCP with 200 and 800 mA, (300 µm)2 × 1.6‐mm cadmium telluride detector, and a dead‐time of 23 ns. A slab‐based assessment used a pair of adipose and iodine with different thicknesses, attenuated X‐rays, and assessed the bias and noise of the outputs from one detector pixel; a CT‐based assessment simulated a chest/cardiac scan and a head‐and‐neck scan using 3D phantom and noisy cone‐beam projections.ResultsWith the slab simulation, the PCP had little or no biases when the expected counts were sufficiently large, even though a probability of count loss (PCL) due to dead‐time loss or PP was as high as 0.8. In contrast, the LCP had significant biases (>±2 cm of adipose) when the PCL was higher than 0.15. Biases were present with both PCP and LCP when the expected counts were less than 10–120 per datum, which was attributed to the fact that the maximum likelihood did not approach the asymptote. The noise of PCP was within 8% from the Cramér–Rao lower bounds for most cases when no significant bias was present. The two CT studies essentially agreed with the slab simulation study. PCP had little or no biases in the estimated basis line integrals, reconstructed basis density maps, and synthesized monoenergetic CT images. But the LCP had significant biases in basis line integrals when X‐ray beams passed through lungs and near the body and neck contours, where the PCLs were above 0.15. As a consequence, basis density maps and monoenergetic CT images obtained by LCP had biases throughout the imaged space.ConclusionWe have developed the PCP algorithm that uses the PP–CS model. When the expected counts are more than 10–120 per datum, the PCP algorithm is statistically efficient and successfully compensates for the effect of the spectral distortion due to both PP and CS providing little or no biases in basis line integrals, basis density maps, and monoenergetic CT images regardless of count‐rates. In contrast, the LCP algorithm, which models an LC due to pileup, produces severe biases when incident count‐rates are high and the PCL is 0.15 or higher.

Characterization of the Total Charge and Time Duration for Single-Event Transient Voltage Pulses in a 65-nm CMOS Technology

This article presents the circuits and heavy-ion irradiation test results of a single-event transient (SET) measurement chip in a 65-nm complementary metal–oxide–semiconductor (CMOS) technology. The measurements contain two parts: total SET ionization charge and SET pulse duration. Transistors with different types and dimensions were implemented as victim devices to evaluate how transistor parameters impact the SET effects. Additionally, SET variation from different supply voltages was also investigated. The test chip has been tested under a heavy-ion beam with an effective linear energy transfer (LET) from 20.4 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$88.35~\text {MeV}\cdot \text {cm}^{2}$ </tex-math></inline-formula> /mg using a 0°–45° incidence angle.

Achieving high pulse charge–discharge energy storage properties and temperature stability of (Ba0.98-xLi0.02Lax)(Mg0.04Ti0.96)O3 lead-free ceramics via bandgap and defect engineering

A novel dual priority strategy of strengthening charge compensation in A-site of perovskite structure and widening bandgap width was designed to prepare (Ba0.98-xLi0.02Lax)(Mg0.04Ti0.96)O3 (BLLMTx) ceramics, which can solve the conflict between polarization and breakdown strength, and improve the pulse energy storage performance of the BaTiO3-based system. As a result, ultrahigh discharge energy density of 3.98 J/cm3 and giant pulse power density of 321.6 MW/cm3 with current density of 2786.4 A/cm2 are obtained at 360 kV/cm for the (Ba0.94Li0.02La0.04)(Mg0.04Ti0.96)O3 (BLLMT0.04) ceramics with considerable fast discharge rate and outstanding temperature stability as well as cycle life, correlating with multi-ferroelectric phases coexistence, increasing bandgap width, strengthening charge compensation and establishing small size of the polar nano-regions (PNRs), which exceeds the great mass of reported lead-free ceramics. The comprehensive properties indicate that the BLLMT0.04 ceramics present potential application in pulse energy storage system. The concept of composition design via increasing bandgap width and strengthening charge compensation provides a new idea for developing lead-free dielectric ceramic capacitors.

An ultra-fast charging strategy for lithium-ion battery at low temperature without lithium plating

Conventional charging methods for lithium-ion battery (LIB) are challenged with vital problems at low temperatures: risk of lithium (Li) plating and low charging speed. This study proposes a fast-charging strategy without Li plating to achieve high-rate charging at low temperatures with bidirectional chargers. The strategy combines the pulsed-heating method and the optimal charging method via precise control of the battery states. A thermo-electric coupled model is developed based on the pseudo-two-dimensional (P2D) electrochemical model to derive charging performances. Two current maps of pulsed heating and charging are generated to realize real-time control. Therefore, our proposed strategy achieves a 3 C equivalent rate at 0 °C and 1.5 C at −10 °C without Li plating, which is 10–30 times faster than the traditional methods. The entropy method is employed to balance the charging speed and the energy efficiency, and the charging performance is further enhanced. For practical application, the power limitation of the charger is considered, and a 2.4 C equivalent rate is achieved at 0 °C with a 250 kW maximum power output. This novel strategy significantly expands LIB usage boundary, and increases charging speed and battery safety.

Stress-regulated pulse charging protocols via coupled electrochemical-mechanical model for the mechanical stability of electrode materials in lithium-ion batteries

The effects of microstructural geometries and C-rates (charge and discharge rates) on mechanical failure have been widely studied to reduce the side reaction and capacity fade in Li–ion batteries. Recently, to achieve the maximum state of charge with least mechanical failure, stress-regulated charging protocols have been considered an emerging strategy. However, the theoretical studies of the charging protocols are limited to either using the equivalent circuit models, or considering only the active material phase. In this paper, we predict the pulse charging profiles by simultaneously controlling the stress level of the active particle and binder, to avoid mechanical failure of the particle, binder, and particle–binder interface. The charging protocol profiles are decided by controlling the stresses within a safe range. The simulations show that both the stress in the active particle and the binder stress and interfacial tractions play important roles in deciding the characteristics of pulse charging profiles, such as duty cycles and pulse frequencies. In addition, the binder constraint significantly affects the use of the pulse charging method. As the particle size and binder stiffness increase, and the binder contact angle decreases, binder stress plays a dominant role in controlling pulse charging. These new insights provide better understanding towards designing fast-charging protocols for Li–ion batteries.

In-situ observation of the Zn electrodeposition on the planar electrode in the alkaline electrolytes with different viscosities

As the dendrite issue is prominent in Zn-based batteries, the regulation of Zn electrodeposition to inhibit the dendrite formation and growth is crucial. Herein, the in-situ observation of electrodeposition process on a planar electrode is performed in this work. The scenarios of operating conditions and electrolyte viscosities are investigated by adjusting charging currents and adding polymer molecules with different concentrations. It is found that the Zn electrodeposition process can be divided into uniform and non-uniform regions, and high currents and high viscosities can prolong the uniform region. Besides, with the increases of current and viscosity, the deposition Zn becomes thinner and compact in the uniform region. The mechanism is proposed as the high current can provide enough electrons which can make the deposition occur besides the deposition tips. The increase in viscosity hinders ion transport, which makes the effect of distance more obvious. Thus, using a high charging current (e.g., pulse charging) and/or an electrolyte with high viscosity are favorable for the uniform deposition of Zn. This work lays the foundation for the improvement of alkaline Zn-based batteries. The optical in-situ observation technology used here is also favorable to explore the deposition process in other electrochemical systems.

A Battery Management System Using Interleaved Pulse Charging With Charge and Temperature Balancing Based on NARX Network

This paper proposes a battery management system, including a fast battery charger, battery aging diagnosis, and charge estimation and balancing. The charger adopts a single-inductor single-input dual-output architecture to achieve charge balancing among battery cells. Interleaved pulse charging is proposed to reduce the charging time and slow down the aging process of batteries as well. This method also significantly suppresses the variations of the temperature of battery cells and is beneficial to the implementation of charge balancing. An artificial neural network is proposed to detect the state of health (SOH) of battery cells and improve the accuracy of the state of charge (SOC) estimation. The prototype is implemented in TSMC 0.35- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> process and TensorFlow tools are used. Measurement results show that the interleaved pulse charging reduces 30% variation of the battery temperature and saves 24% charging time when charging four battery cells concurrently. A mean absolute error of SOC estimation of 0.35% is achieved in this work.

Foreign object monitoring method in aero-engines based on electrostatic sensor

This paper introduces the principle of Ingested Debris Monitoring System in aero-engine and establishes a mathematical model of its core component, the ring-like probe; this paper simulates foreign object's movement based on the established model and performs numerical analysis of the induced charge pulse waveform. Pulse amplitude and pulse width are used as the two pulse features of pulse waveform. Numerical analysis gets the relationship between pulse features and foreign object's charge amount, velocity and radial position. A new method for estimating foreign object's radial position and charge amount has been proposed based on the conclusion of numerical analysis. Both the correctness of numerical analysis and the new estimating method has been verified in the oil calibration test rig. All the relative errors are within 10%. Further experiments with high velocity condition are carried out in an air-gun test rig. The occurrence time, radial position, charge amount, velocity and material category of foreign object can all be obtained, which has important significance to the safety of aero-engines.

Optimal Charging Strategy With Complementary Pulse Current Control of Lithium-Ion Battery for Electric Vehicles

Although the pulse charging strategy has many advantages, it is still controversial. The paradox is that it prolongs the charging time to eliminate the polarization voltage by the pulse interval, and the ac component in pulse current will increase the ohmic losses. In this article, an optimal charging strategy with a complementary pulse current of lithium-ion is proposed to address and alleviate these issues. For the pulse frequency, the optimization can be achieved through the electrochemical impedance spectroscopy (EIS) analysis to reduce the battery’s ac impedance. For the pulse amplitude, based on the battery’s internal resistance characteristics, minimize the ohmic losses to obtain the optimal amplitude. For the pulse duty cycle, it is adjusted to achieve a state of charge (SOC) balancing in the early charging stage, and the battery’s terminal voltage balancing in the later stage. Based on the optimized charging strategy, a pulse charger concept is proposed, which can flexibly control the pulse charging currents and use complementary pulses to completely eliminate the prolonged charging time caused by the pulse interval. In the end, an experimental platform for pulse chargers of lithium-ion batteries is designed, and the theoretical analysis is verified by the comparative experiments.

Comments on “The proactive maintenance for the irreversible sulfation in lead-based energy storage systems with a novel resonance method” (Shengyu Tao, Hongtao Fan, Yang Lei, Xin Xu, Yaojie Sun, Bo You, Yunfang Gao, J Energy Storage 42 (2021) 103093)

• Regeneration of sulfated lead-acid batteries using pulse charge techniques • Link between the pulse charge and the impedance spectra of the electrodes • Electrochemical resonance concept

A Novel Epidemic Model Base on Pulse Charging in Wireless Rechargeable Sensor Networks.

As wireless rechargeable sensor networks (WRSNs) are gradually being widely accepted and recognized, the security issues of WRSNs have also become the focus of research discussion. In the existing WRSNs research, few people introduced the idea of pulse charging. Taking into account the utilization rate of nodes’ energy, this paper proposes a novel pulse infectious disease model (SIALS-P), which is composed of susceptible, infected, anti-malware and low-energy susceptible states under pulse charging, to deal with the security issues of WRSNs. In each periodic pulse point, some parts of low energy states (LS nodes, LI nodes) will be converted into the normal energy states (S nodes, I nodes) to control the number of susceptible nodes and infected nodes. This paper first analyzes the local stability of the SIALS-P model by Floquet theory. Then, a suitable comparison system is given by comparing theorem to analyze the stability of malware-free T-period solution and the persistence of malware transmission. Additionally, the optimal control of the proposed model is analyzed. Finally, the comparative simulation analysis regarding the proposed model, the non-charging model and the continuous charging model is given, and the effects of parameters on the basic reproduction number of the three models are shown. Meanwhile, the sensitivity of each parameter and the optimal control theory is further verified.

Quantitative analysis of the inhibition effect of rising temperature and pulse charging on Lithium dendrite growth

• The effects of temperature on Li dendrites and "dead lithium" are simulated using the phase field model. • The dendrite suppression mechanism of pulse charging strategy is clarified. • The number Da is proposed to analyze quantitatively suppressing of Li dendrites. Lithium (Li) metal is considered a promising negative electrode material for high theoretical energy batteries. However, the growth of Li dendrite increases polarization, reduces battery capacity, and connects the positive and negative electrodes, which will probably lead to explosions. Therefore, inhibiting Li dendrites is critical for Li metal battery application and safety. In this paper, the effect of temperature on Li dendrite is analyzed quantitatively by coupling the nonlinear phase-field and thermal models. The effect of temperature on “dead Li” is also studied. The suitable frequency for Li dendrite inhibition can be obtained by changing the frequency of the pulse charging. On the basis of the simulation results, the mechanisms of inhibiting Li dendrites by rising temperature and pulse charging are also analyzed. The investigation of the average growth rate of dendrites under different overpotential values and diffusion coefficients indicates that the gap between the reaction and diffusion rates must be narrowed to inhibit Li dendrites. This work provides a deep understanding of and direction toward inhibiting Li dendrites.