Different Depths Of Discharge Research Articles

Understanding the Phase Transitions in Tin Foil Electrodes for Sodium-Ion Batteries through Light Microscopy and Kinetic Analysis

Group IVA elements exhibit some interesting sodium capabilities via electrochemical alloying processes (except carbon). Among them, tin is believed to be the most promising anode candidate for sodium-ion batteries (SIBs) due to its simple fabrication and monolithic form (e.g., metallic foils).[1] Nevertheless, tin foil anodes usually fail prematurely after only a handful of cycles. This poor reversibility is reported to be largely associated with the structural collapse of tin electrodes caused by huge volume differences among various Na-Sn phases (up to ~420%).[2][3] The volume change and the number of stress-induced cracks during different phase transitions can be different, given that these intermediate sodium-containing tin phases have different crystal structures and mechanical properties.[4] To prolong the lifetime of tin foil electrodes, it is crucial to determine which phase transitions have a greater impact on crack formation in the tin electrode and deliberately mitigate the problematic phase transitions.In this work, the mechanisms and kinetics of the phase transitions that occur in the sodiation of tin foil are extensively investigated using operando light microscopy and robust electrochemical techniques. Ex situ X-ray diffraction (XRD) (Figure 1) reveals that the initial sodiation of tin foil begins with a significant crystalline to amorphous transition (i.e., c-Sn to a-NaSn), followed by the a-NaSn to c-Na9Sn4 and the c-Na9Sn4 to c-Na15Sn4 transitions. To further understand these transitions, we introduce a new battery configuration for light microscopy to observe the dynamic change of the cross-section macrostructure of tin foil electrodes during cycling. It is expected that the observation could partly quantify the volume expansion during different phase transitions, directly visualize the formation of cracks, and accurately estimate the sodium diffusion coefficient in tin foil electrodes. Moreover, the change of charge transfer resistance as a function of sodiation depth is measured using electrochemical impedance spectroscopy (EIS), shedding light on the degradation mechanism. Besides, potentiostatic intermittent titration technique (PITT) is also employed to determine the role of diffusion or interfacial charge transfer on the whole kinetics of tin anode at different depths of discharge. These investigations could yield fundamental insights into the sodiation mechanisms and kinetics of tin foil electrodes, and more importantly, provide guidance for the utilization of binder- and additive-free tin foil as a reliable SIB anode. Figure 1

An Investigation on the Electrochemical and Thermal Characteristics of LiMn0.6Fe0.4PO4/LiNi0.5Co0.2Mn0.3O2 Composite Cathode Materials for Lithium-Ion Batteries in Different Health States

This paper studied the electrochemical performance and heat generation characteristics of 18650 LiMn0.6Fe0.4PO4/LiNi0.5Co0.2Mn0.3O2 (LMFP/NCM) composite cathode materials for lithium-ion batteries under different states of health (SOH) (98%, 90% and 82%). The discharge performance, temperature rise and heat generation of these three batteries were investigated at different discharge rates and different temperatures. The electrochemical impedance spectroscopy (EIS), internal resistance and entropy heat coefficient at different depths of discharge (DOD) were analyzed. The results showed the internal resistance and irreversible heat generation increased with the decrease of battery SOH value. The entropy heat coefficient significantly increased at 0.5 DOD, and the maximum total heat generation power was also obtained at 0.5 DOD. The maximum heat generation power of 90% and 82% SOH batteries at 0.5 DOD increased by 175% and 208% than 98% SOH battery when discharging at 2 C, respectively. The battery with 82% SOH had the highest temperature rise (7.5 °C) and total heat generation power (3.12 W), and the ratio of reversible to irreversible heat generation was the lowest (0.152) at −10 °C. It provided a theoretical basis for optimizing the thermal management of LMFP/NCM batteries.

Estimating the Health Status of Li-ion NMC Batteries From Energy Characteristics for EV Applications

Capacity and Direct Current Internal Resistance are good health indicators for Li-ion batteries. But they cannot be measured. This work proposes to estimate these indicators from already available current and voltage measurements. The estimators are based on third-order polynomials and energy features extracted during partial discharge and different depths of discharge under a dynamic profile (World harmonized Light vehicles Test Cycles). The estimations are validated with experimental measurements obtained from cycling three Lithium-Nickel-Manganese-Cobalt-Oxide/Graphite cells at a controlled temperature. The mean relative error for the Direct Current Internal Resistance estimation is less than 5% when the depth of discharge lies between 25% and 40%. It is lower than 2% for the capacity estimation. The method is simple and suitable for embedded battery monitoring as it uses already available voltage and current measurements.

Low Temperature Research and Improvement on Lithium Ion Batteries

Lithium ion batteries have been the dominant power sources in portable electronics and electric vehicles due to their high energy density, long lifetime and environmental benignity. However, it is a big challenge for lithium ion batteries to be used at low temperature. Compared with the performance at room temperature, lithium ion batteries deliver much less capacity and energy at low temperature. The poor low temperature performance restricts the usage of lithium ion batteries for power electronics and electric vehicles in the winter. The results of previous research, suggest that the poor low temperature performance is attributed to the freezing of the liquid electrolyte which leads to low ionic conductivity and high interfacial resistance, especially on the anode side. Other researchers tried using a solvent with low melting point to partially replace ethylene carbonate or adding some additives to the electrolyte to enhance the ionic conductivity or modify the interface to reduce the resistance and then deliver more capacity and energy.In this research, we investigated the discharge capacity, energy, pulse power and electrochemical impedance spectroscopy at different depths of discharge of NCM622/Graphite lithium ion batteries at varied temperatures. We found that the discharge energy and pulse power are sensitive to the temperature decreasing. For the NCN622/Graphite cell (2.5 mAh cm-2) with commonly used LiPF6-EC/EMC electrolyte, at -20 oC the cell is able to deliver 65% capacity of that at 30 oC with C/3 discharge current rate, while the delivered energy is only 60%. The 30 seconds pulse power became much worse at -20 oC compared with the power at room temperature. In our research the poor low temperature performance is not from the low ionic conductivity and interfacial resistance. The dominant factor is the charge transfer impedance from the cathode side of the cell.To improve the low temperature performance, we explored the addition inexpensive nano-particles as the additive into the electrolyte. The cell composed of this electrolyte is able to release more than 70% capacity and energy at -20 oC of that measured at 30 oC. The charge transfer resistance in the fully charge state decreased almost 80% compared to a cell with baseline electrolyte. Meanwhile, the additive has no effect on the long-term cycling (1000 cycles) and stability at high temperature (55 oC) Fig.1. Normalized capacity and energy. Fig.2. The EIS of the full cell at 30 oC and -20 oC. Figure 1

Lithium-ion ferrous phosphate prismatic cell aging analysis and assessment for the development of battery management systems

Electric off-road vehicles are gaining popularity as an alternative to fossil fuel-driven vehicles due to their efficiency and eco-friendliness. A series of numerical modelling and experimentation analysis is required to evaluate the trade-off between battery accuracy and life span to identify optimal battery management system design. In this study, investigations were carried out on a lithium-ion ferrous phosphate (LFP) prismatic cell in an electric-powered farm tiller application using the single particle model (SPM) method. The SPM method was used to analyse the battery's behaviour during charge–discharge profiles at 0.5, 1, and 2C ratings. By applying SPM discharging profiles, the Newman, Tiedemann, Gu, and Kim (NTGK) empirical analysis carried out cascaded thermal investigations. The NTGK and experimental studies showed a difference in the error of 0.23 %, 0.38 %, and 0.65 % for the 0.5, 1, and 2C ratings, respectively. Model order reduction (MOR) studies were performed to compute the heat generation rate in a prismatic cell comprising electrode pairs, separators, and current collectors. A parallel study of electrochemical impedance spectroscopy (EIS) experimentation was performed to evaluate the charge transfer resistance analysis for 500, 1000, and 1500 cyclic operations under different depths of discharge (DOD) conditions. The EIS studies assessed charge transfer resistance at maximum DOD conditions for the mentioned cyclic operations were found to be 135, 140, and 164 mΩ.

Capacity Degradation and Aging Mechanisms Evolution of Lithium-Ion Batteries under Different Operation Conditions

Since lithium-ion batteries are rarely utilized in their full state-of-charge (SOC) range (0–100%); therefore, in practice, understanding the performance degradation with different SOC swing ranges is critical for optimizing battery usage. We modeled battery aging under different depths of discharge (DODs), SOC swing ranges and temperatures by coupling four aging mechanisms, including the solid–electrolyte interface (SEI) layer growth, lithium (li) plating, particle cracking, and loss of active material (LAM) with a P2D model. Additionally, the mechanisms causing accelerated capacity to drop near a battery’s end of life (EOL) were investigated systematically. The results indicated that when the battery operated with a high SOC range, the capacity was more prone to accelerated degradation near the EOL. Among the four degradation mechanisms, li plating was mainly sensitive to the operation temperature and SOC swing ranges, while the SEI growth was mainly sensitive to temperature. Furthermore, there was an inhibitory interaction between li plating and SEI growth, as well as positive feedback between LAM and particle cracking during battery aging. Additionally, we discovered that the extremely low local porosity around the anode separator could cause the ‘knee point’ of capacity degradation.

Study on failure mechanism on rechargeable alkaline zinc-Air battery during charge/discharge cycles at different depths of discharge.

Background: Zinc-air battery (ZAB) is a promising candidate for energy storage, but the short cycle life severely restricts the wider practical applications. Up to date, no consensus on the dominant factors affecting ZABs cycle life was reached to help understanding how to prolong the ZAB's cycle life. Here, a series of replacement experiments based on the ZAB were conducted to confirm the pivotal factors that influence the cycle life at different depths of discharge (DOD). Method: The morphology and composition of the components of the battery were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and chemical titration analyses. Result: SEM images and XRD results revealed that the failure of the zinc anode gradually deepens with the increase of DOD, while the performance degradation of the tricobalt tetroxide/Carbon Black (Co3O4/CB) air cathode depends on the operating time. The concentration of CO3 2- depends on the charge/discharge cycle time. The replacement experiments results show that the dominant factors affecting the ZAB's cycle life is the reduction of active sites on the surface of Co3O4/CB air cathode at a shallow DOD, while that is the carbonation of the electrolyte at a deep DOD. The reduction of active sites on the surface of Co3O4/CB air cathode is caused by the coverage of K2CO3 precipitated by carbonation of the electrolyte, suggesting that the carbonation of the alkaline electrolyte limits ZAB's cycle life. Conclusion: Therefore, this work not only further discloses the failure mechanism of ZAB, but also provides some feasible guidance to design a ZAB with along cycle life.

Experimental Investigation of Overdischarge Effects on Commercial Li-Ion Cells

Due to their attractive properties, such as high energy and power density, Lithium-ion batteries are currently the most suitable energy storage system for powering portable electronic equipment, electric vehicles, etc. However, they are still affected by safety and stability problems that need to be solved to allow a wider range of applications, especially for critical areas such as power networks and aeronautics. In this paper, the issue of overdischarge abuse has been addressed on Lithium-ion cells with different anode materials: a graphite-based anode and a Lithium Titanate Oxide (LTO)-based anode model. Tests were carried out at different depths of discharge (DOD%) in order to determine the effect of DOD% on cell performance and the critical conditions that often make the cell fail irreversibly. Tests on graphite anode cells have shown that at DOD% higher than 110% the cell is damaged irreversibly; while at DOD% lower than 110% electrolyte deposits form on the anodic surface and structural damage affects the cathode during cycling after the overdischarge. Furthermore, at any DOD%, copper deposits are found on the anode. In contrast with the graphite anode, it was always possible to recharge the LTO-based anode cells and restore their operation, though in the case of DOD% of 140% a drastic reduction in the recovered capacity was observed. In no case was there any venting of the cell, or any explosive event.

Understanding the Parameters Influencing the Impedance Response of Sulfur-Carbon Composite Cathode in Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries, which in recent years have been aimed at a high gravimetric energy density of 500-600 Wh kg-1, indicate particular potential in aerospace applications such as aircraft, satellites and drones.1,2 In light of this, the German Aerospace Center (DLR) has been pursuing a strategy of developing and researching metal-sulfur batteries for a decade. Herewith, we present the results of a fundamental study on the investigation of structural and compositional parameters affecting the electrochemical performance of sulfur-carbon composite cathode.Highly porous carbon materials are widely employed in composite cathodes in Li-S batteries to compensate for the non-conductive property of the sulfur element. Indeed, this would have significant effects not only on the conductivity of the cathode, but also on the diffusion and charge transfer parameters. Herewith, we have systematically studied porous carbon-based electrodes employing electrochemical impedance spectroscopy. Using a suitable transmission-line model peculiar to the porous electrodes, the resistance of bulk and pore electrolyte, inter-particles, and charge transfer is defined and quantified. The dependence of the identified processes at the open circuit voltage on the fraction of the active material, the porosity of utilized carbon and thickness of the electrode is investigated elaborately. It is indicated that the electrolyte resistance in the pore increases on increasing the content of active material, electrode thickness and on reducing the pore size distribution of the C component.Additionally, an innovative symmetrical three-electrode cell configuration with an integrated Li-ring serving as counter electrode is implemented, enabling the investigation of the cathode impedance at different depths of discharge to shed light on the kinetics of the charge transfer depending on the infiltration method. To this end, various porous carbon materials such as Ketjenblack® (mesoporous) and carbon aerogel (microporous) in combination with different sulfur infiltration techniques including gas, melt and mechanical mixing have been employed as model systems3. The thermodynamic and kinetics of charge transfer mechanisms as a function of infiltration method as well as the variation of the charge transfer resistances upon discharge/charge are discussed in details4. A. Fotouhi, D. J. Auger, L. O’Neill, T. Cleaver and S. Walus, Energies, 2017, 10, 1937.Sripad S., Viswanathan V. (2017), ACS. Energy. Lett.2, 1669-1673M. Nojabaee, B. Sievert, M. Schwan, J. Schettler, F. Warth, N. Wagner, B. Milow, K. Andreas Friedrich, J. Mater. Chem. A, 2021,9, 6508-6519.Martina Gerle, Norbert Wagner, Joachim Häcker, Maryam Nojabaee, Andreas Friedrich J. Electrochem. Soc., 2022, 169, 030505.

Heat generation and surrogate model for large-capacity nickel-rich prismatic lithium-ion battery as against 18650 battery

Large-capacity lithium batteries are being widely used as the power sources of new energy vehicles due to the advantages of easy assembly and simplified electrical connections. However, the temperature rise and thermal safety issues would become more severe for larger capacity batteries with smaller specific areas due to more concentrated heat generation and accumulation thereof. In this paper, an experimental study is presented for the thermal characteristics and thermal performance of a commercial large-capacity lithium battery over 100 Ah. The orthogonal experiment protocol was designed to obtain the direct current internal resistance and entropy coefficient of battery under varying working conditions involving the temperature and depth of discharge. It was found that the discharge rate had little effect on the entropy coefficient and direct current internal resistance, and the average entropy coefficient of a battery with high nickel content and specific energy was lower. Meanwhile, the electrochemical impedance spectroscopy of a battery in different placement orientations was also tested. The results indicated that the ohmic impedance and charge transfer impedance of the battery in the upright orientation were slightly smaller than that in the lying-down orientation, which is preferred in practical operation. The battery heat generation rate is gained by combining the measured internal resistance and entropy coefficient terms. A third-order surrogate model of heat generation rate is correlated under different working conditions with the depth of discharge, temperature, and discharge rate by the response surface analysis (RSA). In addition, the volumetric heat generation rate of the present large-capacity prismatic battery is compared with a smaller 18650 battery. The battery temperature rise under natural convection condition was experimentally measured, together with the measured specific heat, to examine the validity of the present heat generation model. Finally, the heat generation surrogate model was applied in WLTC conditions, and the temperature rises of the battery under different depths of discharge were obtained and discussed.

Revealing the Effects of Structure Design and Operating Protocols on the Electrochemical Performance of Rechargeable Zn-Air Batteries

Rechargeable zinc-air batteries (RZABs) provide a competitive complement to various kinds of batteries, and great efforts are made in elective electrode materials. For given electrodes, the battery performance is correlated to the structural design and operating conditions. Herein, the effects of structural design and operating protocols on the electrochemical performance of RZABs are investigated systematically. As the distance between the positive and negative electrodes decreases, although the power density increases, the discharge capacity is significantly reduced due to the easier surface passivation. In addition, since the mass of the electrolyte accounts for a large proportion of the battery, the actual energy density is much lower than the theoretical one. Further, the cycle stability at different depths of discharge is similar before the saturation of but drops sharply after ZnO appears. To explore the impacts of operating protocols, a three-dimensional model with the same size of the actual battery is established. The simulation results show that the intermittent charge-discharge and the low-current-density operation make the ion concentration more uniform, which is beneficial to improve the cycle stability. This work provides a profound understanding of the device-level structure design and operating protocols, guiding the design of high-performance RZABs.

Lithiation phase behaviors of metal oxide anodes and extra capacities

Binary metal oxides have received sustained interest as anode materials due to their desirable capacities, exceeding theoretical values particularly in the first discharge. Although they have received increasing attention in recent years, topical debates persist regarding not only their lithiation mechanisms but also the origin of additional capacity. Aiming to resolve these disagreements, we perform a systematic study of a series of iron and manganese oxides to investigate their phase behavior during first discharge. Using a combination of in operando pair distribution function measurements and our recently developed Metropolis non-negative matrix factorization approach to address the analytical challenges concerning materials’ nanoscopic nature and phase heterogeneity, here we report unexpected observation of non-equilibrium FeO x solid-solution phases and pulverization of MnO. These processes are correlated with the extra capacities observed at different depths of discharge, pointing to a metal-dependent nature of this additional capacity and demonstrating the advantage of our approach with promising prospects for diverse applications. The extra capacity may have a dominant source depending on specific metal species bcc -FeO x intermediate lithiate via oxygen extraction from the Fe sublattice Local structure characterization using pair distribution function Robust phase deconvolution using Metropolis non-negative matrix factorization Binary metal oxide anodes in lithium-ion batteries show extra capacities at their initial discharge. In this article, Hua et al. perform a systematic study of iron and manganese oxides’ lithiation phase behaviors and report unexpected observations of bcc -FeO x solid solution and MnO pulverization, processes correlated with the extra capacities seen at different depths of discharge.

Modeling and Analysis of Heat Dissipation for Liquid Cooling Lithium-Ion Batteries

To ensure optimum working conditions for lithium-ion batteries, a numerical study is carried out for three-dimensional temperature distribution of a battery liquid cooling system in this work. The effect of channel size and inlet boundary conditions are evaluated on the temperature field of the battery modules. Based on the thermal behavior of discharging battery obtained experimental measurements, two temperature control strategies are proposed and studied. The results show that the channel width of the cooling plates has a great influence on the maximum temperature in the battery module. It is also revealed that increasing inlet water flow rate can significantly improve the heat transfer capacity of the battery thermal management system, while the relationship between them is not proportional. Lowering the inlet temperature can reduce the maximum temperature predicted in the battery module significantly. However, this will also lead to additional energy consumed by the cooling system. It is also found that the Scheme 5 among various temperature control strategies can ensure the battery pack working in the best temperature range in different depths of discharge. Compared with the traditional one with a given flow rate, the parasitic energy consumption in Scheme 5 can be reduced by around 80%.

Zirconium disulfides as an electrode material alternative for Li-ion batteries

In this study, we report the electrochemical reaction mechanism and structural evolution of zirconium disulfide (ZrS2) electrode materials for Li-ion batteries, analogous to titanium disulfide (TiS2), known as the first intercalation compound. To minutely explore the electrochemical behaviors of the ZrS2 electrode in Li-ion cells, we conducted galvanostatic charge/discharge and cyclic voltammetry measurements at different depths of discharge, thereby observing the reaction change characteristics between the intercalation and conversion reactions. Furthermore, structural changes in the ZrS2 electrodes collected at different electrochemical states were investigated by ex-situ characterizations to identify the electrochemical reaction behaviors in detail. Our basic study on ZrS2 can provide important information and directions for those considering the electrochemical properties and design of ZrS2 for alkali-ion batteries.

Optimized Ni‐Rich NCMA Cathode for Electric Vehicle Batteries

AbstractThe electrochemical and structural stabilities of a conventional Li[Ni0.90Co0.045Mn0.045Al0.01]O2 (NCMA90) cathode and a core–shell with concentration gradient cathode (CSG‐NCMA90) are evaluated by cycling the cathodes at different depths of discharge (DoDs). The CSG‐NCMA90 cathode consists of fine, elongated primary particles that are radially aligned from the center of a spherical secondary particle. This unique microstructure effectively suppresses microcrack formation and propagation in the highly charged state. Moreover, microstructural analysis through transmission electron microscopy reveals that the thin elongated primary particles, largely featuring (001) facets on their lateral sides, are tolerant of electrolyte attack, thus suppressing surface degradation. In a full cell, these microstructural features enable the CSG‐NCMA90 cathode to retain 90.7% of its initial capacity after 1000 cycles at 100% DoD. Unlike conventional Ni‐rich layered cathodes whose capacity should be restricted to ≈60–80% to ensure their long service life, the proposed CSG‐NCMA90 cathode can be cycled at full capacity, thus facilitating higher electrochemical performance and realizing the development of economical Li‐ion batteries.

Dynamics of Electrical Activity of Olfactory Structures under Conditions of Calypsol / Ketamine Anesthesia

Introduction. In this study, we have characterized high-frequency and low-frequency oscillations at several stages of olfactory processing under calypsol anesthesia in albino rats. While monitoring the animal's respiration, we also obtained field potentials from the olfactory bulb and piriform (olfactory) cortex and simultaneously recorded membrane potentials in piriform cortex pyramidal cells. Manifestations of the considered specific high-frequency components of electrical activity of rhinencephaly structures, in particular olfactory-amygdala rhythm and high-frequency synchronized activity, are obviously the resultof complex interaction of peripheral and central excitation mechanisms at the level of olfactory bulbs. We believe this finding has important functional as well as evolutionary implications.Purpose. To investigate the temporal dynamics of the manifestations of the phenomena of electrical activity of the olfactory bulb of rats and its changes under calypsol anesthesia.Methods.Stereotactic and electroencephalographic methods, correlation-spectral and coherent analysis of the obtained records of electricalactivity of the brain structures were used to study the bioelectrical activity of olfactory structures of the brain of experimental animals.The work was performed in a chronic experiment on 12 outbred white rats, males weighing 200 g. A premedication cocktail and calypsol at a rate of 25 mg / kg of animal weight were used for anesthesia. Implantation control was carried out according to specific patterns of electrical activity of the studied structures.The bioelectrical activity of the brain of each animal was studied for 10-20 days, followed by morphological control.Results. Olfacto-amygdala rhythm is registered against the background of polymorphic activity on the peak of respiratory waves in the form of spindle-shaped flashes of high-frequency oscillations in the range of 52-95 Hz, variable in amplitude. Simulation of the sustained suppression state of olfacto-amygdala rhythm in rhinencephalic structures was achieved using the technique of transferring animals to a state of deep ketamine (calypsol) anesthesia. This allowed not only to "exclude" flashes of olfactory-amygdala rhythm, but also to significantly suppress the high-frequency components of the spectra of electrical activity of olfactory bulbs, to increase the manifestation of low-frequency components (p <0.01-0.05) and to probably reduce the index of high-frequency waves (р<0.05). ISSN 2076-5835. Вісник Черкаського університету. 2021 No247Deep calypsol anesthesia caused differences in the spectra of electrical activity of olfactory bulbs at different depths of discharge only in terms of the spectral power density of the slow-wave range. At the same time, identical probable (p <0.05) suppression of high-frequency components of electrical activity of olfactory bulbs was observed.Under these conditions, the preservation of high-frequency components of the spectrum (unformed in spindles) in the electrical activity of olfactory bulbs at the border of mitral and granular cells was observed even under conditions of sharp depression of -activity in ECoG and identical dominance of high-amplitude low-frequency oscillations in the amygdala.Originality. The influence of narcotic substances on the dynamics of manifestations of the phenomena of electrical activity of rhinencephalic structures: respiratory waves, olfacto-amygdala rhythm, polymorphic activity, is revealed.Conclusions.It is expedient to use the following amplitude-time patterns for objective characterization of total electrical activityof olfactory structures of rats, whichprobably differ in power-frequency characteristics: polymorphic desynchronized activity, respiratory waves, olfacto-amygdala synchronous rhythm and high-frequency synchronous rhythm.Polymorphic activity is normally represented by low-amplitude oscillations (10-200 μV) in a wide frequency range (10-150 Hz) with a set of dominant extremes. Оlfactory-amygdala rhythmis registered against the background of polymorphic activity on the peak of respiratory waves in the form of spindle-shaped flashes of high-frequency oscillations in the range of 52-95 Hz, variable in amplitude.Experimental modeling of the state of stable suppression of olfacto-amygdala rhythm and high-frequency synchronized activity in the electrical activity of olfactory bulbs (under colipslol / ketamine anesthesia) revealed suppression of manifestations of high-frequency components of the spectrum, indicating the important role of centrifugal effects inthe mechanisms of olfactory rhythm generation.Key words:electrical activity, olfactory bulb, fast oscillations, slow oscillations, excitation, anesthesia

A Health Indicator for the Online Lifetime Estimation of an Electric Vehicle Power Li-Ion Battery

With the further development of the electric vehicle (EV) industry, the reliability of prediction and health management (PHM) systems has received great attention. The original Li-ion battery life prediction technology developed by offline training data can no longer meet the needs of use under complex working conditions. The existing methods pay insufficient attention to the dispersive information of health indicators (HIs) under EV driving conditions, and can only calculate through standard configuration files. To solve the problem that it is difficult to directly measure the capacity loss in real time, this paper proposes a battery HI called excitation response level (ERL) to describe the voltage variation at different lifetimes, which could be easily calculated according to the current and voltage under the actual load curve. In addition, in order to further optimize the proposed HI, Box–Cox transformation was used to enhance the linear correlation between the initially extracted HI and the capacity. Several Li-ion batteries were discharged to the 50% state of health (SOH) through profiles with different depths of discharge (DODs) and mean states of charge (SOCs) to verify the accuracy and robustness of the proposed method. The average estimation error of the tested batteries was less than 3%, which shows a good performance for accuracy and robustness.

Innovative Scaled Hardware Simulator for Designing and Testing an EV’s Battery Storage System Incorporated with an Adaptive ANN Model

In this study, a scaled-down system, which can be used as a benchmark test for the battery storage designing of electric vehicles (EVs) is proposed. This model was based on the hardware simulator of the battery storage system (BSS) used from a single cell up to 4 cells in a series pack system, which simulates a practical battery pack. The developed simulator can charge and discharge any rechargeable battery, such as Li-Ion, Ni–MH or Pb battery. The scaling ratio of the simulator was evaluated by the ratio of the current or power of the battery pack specimen related to the specification. Also, this study proposes an innovative state of charge (SoC) estimation of the battery pack for EVs based on genuine results obtained through practical tests. This estimation was carried out by an adaptive artificial neural network (ANN) algorithm, using simple inputs. As well, this model can deduct the state of health (SoH) of the battery pack based on the power output level and waveform characteristics. The results of the ANN showed high generalization, a low error of SoC estimation at the level of 1.1%, with a calculation time less than 16.5 s. Regarding the hardware simulator, the similarity of the results and waveform accuracy of the scaled-down battery systems compared with the real battery pack was very acceptable with a maximum deviation of 2.1% in the worst scenario. The cells cycled with different depths of discharge (DoD) or C-rates, at different temperatures with different initial SoCs using any arbitrary current waveforms. Our conclusions will help battery manufacturers to test and evaluate the performance of the BSS in different applications, such as EVs, PV generation, and wind farm, with significant cost reduction. Also, the ANN algorithm can be used and embedded in EVs or in any other industrial application, as proposed in this paper. This study contributed to the real-time diagnosis of the BSS without interrupting the normal operation based on its features.

Analysis of Heat Generation and Impedance Characteristics of Prussian Blue Analogue Cathode-based 18650-type Sodium-ion Cells

We report here 18650-type sodium-ion battery (NIB) with Prussian Blue Analogue Na2Fe2(CN)6 in both monoclinic and rhombohedral phases as the cathode and hard carbon (HC) as the anode using the glyme-based non-flammable 1 mol dm−3 NaBF4 electrolyte. Rhombohedral-Na2Fe2(CN)6 (RPB) vs HC 18650-type cell delivered an energy density of 43 Wh kg−1, achieving good high rate response up to 4.0 C, stable cycling over 100 cycles with 99.99% average coulombic efficiency and 94.8% average round-trip-energy-efficiency. A comparison of the calorimetric studies performed on 18650-type cells revealed lower heat generation in RPB vs HC compared to monoclinic-Na2Fe2(CN)6.2H2O (MPB) vs HC counterpart. Moreover, the RPB vs HC cell demonstrated lower heat generation than commercial NMC vs graphite 18650-type lithium-ion cells. Internal resistance, which is the major contributor to heat generation, is assessed by analysing the impedance spectra of the cells. Furthermore, variation in subcomponents of internal resistance across different depths of discharge determined by fitting impedance data using an equivalent circuit model and analysis using distribution of relaxation times (DRT) method is presented for 18650-type sodium-ion cells for the first time. The obtained results indicate that these efficient and safe 18650-type NIBs open-up new opportunities for exploring innovative storage systems for stationary applications.

Anomalous Discharge Behavior of Graphite Nanosheet Electrodes in Lithium-Oxygen Batteries.

Lithium-oxygen (Li-O2) batteries require rational air electrode concepts to achieve high energy densities. We report a simple but effective electrode design based on graphite nanosheets (GNS) as active material to facilitate the discharge reaction. In contrast to other carbon forms we tested, GNS show a distinctive two-step discharge behavior. Fundamental aspects of the battery’s discharge profile were examined in different depths of discharge using scanning electron microscopy and electrochemical impedance spectroscopy. We attribute the second stage of discharge to the electrochemically induced expansion of graphite, which allows an increase in the discharge product uptake. Raman spectroscopy and powder X-ray diffraction confirmed the main discharge product to be Li2O2, which was found as particulate coating on GNS at the electrode top, and in damaged areas at the bottom together with Li2CO3 and Li2O. Large discharge capacity comes at a price: the chemical and structural integrity of the cathode suffers from graphite expansion and unwanted byproducts. In addition to the known instability of the electrode–electrolyte interface, new challenges emerge from high depths of discharge. The mechanistic origin of the observed effects, as well as air electrode design strategies to deal with them, are discussed in this study.