batterydata/paper-abstracts huggingface dataset:
The performance of lithium-ion battery packs are often extrapolated from single cell performance however uneven currents in parallel strings due to cell-to-cell variations, thermal gradients and/or cell interconnects can reduce the overall performance of a large scale lithium-ion battery pack. In this work, we investigate the performance implications caused by these factors by simulating six parallel connected batteries based on a thermally coupled single particle model with the solid electrolyte interphase growth degradation mechanism modelled. Experimentally validated simulations show that cells closest to the load points of a pack experience higher currents than cells further away due to uneven overpotentials caused by the interconnects. When a cell with a four times greater internal impedance was placed in the location with the higher currents this actually helped to equalise the cell-to-cell current distribution, however if this was placed at a location furthest from the load point this would cause a ∼6% reduction in accessible energy at 1.5 C. The influence of thermal gradients can further affect this current heterogeneity leading to accelerated aging. Simulations show that in all cases, cells degrade at different rates in a pack due to the uneven currents, with this being amplified by thermal gradients. In the presented work a 5.2% increase in degradation rate, from −7.71 mWh/cycle (isothermal) to −8.11 mWh/cycle (non-isothermal) can be observed. Therefore, the insights from this paper highlight the highly coupled nature of battery pack performance and can inform designs for higher performance and longer lasting battery packs.
Enteromorpha prolifera (E.prolifera), an ocean biomass, was used as raw materials to prepare active carbons by a two-step strategy (pre-carbonization followed by chemical activation). The as-prepared active carbons have been characterized by a variety of means such as N2 adsorption, field emission scanning electron microscope, transmission electron microscope, Raman spectroscopy. The results showed that the carbons have large surface area and developed porosity with micro-meso hierarchical pore texture. As evidenced by electrochemical measurements, the specific capacitance of the carbons can reach up to 296 F g−1. More importantly, the carbons can maintain a high capacitance of up to 152 F g−1 at a very high current density of 30 A g−1, highlighting the promise of the carbons for high power applications.
Recent theoretical work has uncovered that a body-centered-cubic (bcc) anion arrangement leads to high ionic conductivity in a number of fast lithium-ion conducting materials. Using this structural feature as a screening criterion, we find that the I material LiZnPS4 contains such a framework and has the potential for very high ionic conductivity. In this work, we apply ab initio computational techniques to investigate in detail the ionic conductivity and defect properties of this material. We find that while the stoichiometric structure has poor ionic conductivity, engineering of its composition to introduce interstitial lithium defects is able to exploit the low migration barrier of the bcc anion framework. Our calculations predict a solid-solution regime extending to x = 0.5 in Li1+2xZn1−xPS4, and yield a new ionic conductor with exceptionally high lithium-ion conductivity, potentially exceeding 50 mS cm−1 at room temperature.
The dynamic thermal and electrical behavior of high power LiFePO4 cathode-type Li-ion batteries is studied with extended considerations such as demanded current ranging from 12 to 30A, battery temperatures ranging from 283 to 313K and a redefinition of the concept of state of charge during cycling conditions. The equivalent electrical model, consisting of a series resistance, a parallel resistance–capacitor, a voltage source and state of charge calculators, can be improved with the addition of current and temperature gains for each element. In addition, a non-intrusively-obtained alternative thermal model extraction is proposed to uncouple from the experimental battery temperature based on electrochemical research found in the literature. This improved model extraction for high power cylindrical batteries can achieve a temperature and voltage relative runtime error in the range of 1% and 5% in average, respectively. The effects of lithium concentration in the anode and cathode are accurately predicted with state of charge accelerators, which vary linearly with temperature. Aiming for a power systems environment, the integrated battery model is built and validated experimentally to demonstrate its accurate prediction. This improved integrated battery model can be employed for battery stack simulations, improved state of charge algorithm testing and optimization of hybrid systems - with a light computational demand. Finally, a performance index radar plot is proposed to conveniently compare electrical and thermal properties of different types of batteries.
In this article, we discuss each of the major indoor and outdoor air pollutants, how these air pollutants are dispersed in the environment, and what human health effects have been associated with either short-term or long-term exposures to these air pollutants. The focus of the article is on human-derived anthropogenic emissions of air pollution (e.g., from fossil fuel combustion), rather than those from natural causes (e.g., pollens).
There are many reports on electrochemical anion intercalation into graphite using different types of electrolyte mixtures for application in dual-graphite or dual-ion cells, showing promising results in terms of cycling stability, reversible capacity and Coulombic efficiency. However, there is no clear understanding of the influence of the anion/electrolyte characteristics on the intercalation properties. In this work, we present a comprehensive study of the intercalation behavior of a series of imide-based ionic liquid (IL) electrolytes into a graphite positive electrode with special emphasis on the influence of anion size on the electrochemical parameters such as the onset potential for anion uptake and the reversible capacity. The onset potentials of anion intercalation into graphite ranged between 4.42V to 4.53V vs. Li/Li+ with the following descending order for the studied anions: BETI>FSI>FTFSI>FSI/TFSI (molar ratio=11:1)>TFSI>TFSI/FSI (molar ratio=10:1). The electrochemical results support the assumption that electrolyte effects such as ion pair formation and self-aggregation in the electrolyte overrule the influence of the anion size (up to a certain point) in terms of the onset potential for anion uptake. The charge/discharge cycling performance was studied in view of reversible capacity and Coulombic efficiency. In this context, the BETI system shows only very poor intercalation ability whereas the quaternary mixture TFSI/FSI displays a very promising cycling behavior providing a specific capacity of ∼54mAhg−1 with a Coulombic efficiency exceeding 99%. Furthermore, the characteristics of the different imide-based electrolytes such as the oxidative stability (TFSI>BETI>FTFSI>TFSI/FSI>FSI/TFSI>FSI) as well as the influence on aluminum current collector dissolution were studied to draw further conclusions about impact on the Coulombic efficiency.
Home sleep apnea testing (HSAT) has increased due to improvements in technology, accessibility, and changes in third party reimbursement requirements. Research studies using HSAT have not consistently reported procedures and methodological challenges. This paper had two objectives: (1) summarize the literature on use of HSAT in research of adults and (2) identify methodological strategies to use in research and practice to standardize HSAT procedures and information.
Europe's regulation of passenger car emissions has been proven to have failed when it comes to nitrogen oxide emissions (NOx) by diesel engines. Due to historical decisions favouring diesel technology, Europe has become a diesel island with no equal worldwide. As a result, virtually every European citizen breathes in air which is deemed harmful to human health. Real driving emissions (RDE) testing by means of portable emissions measurement systems (PEMS) can potentially eliminate the discrepancy between lab and road tests, and will complement the dynamometer type-approval procedure from September 2017 onwards. Despite the significant potential of PEMS testing, the emission assessment has been watered down through politics to provide the automotive manufacturers with additional lead-time. In this way, the lab to road gap is not eliminated but only decreased. This means that diesel cars will continue to over-emit NOx until the 2020s at earliest. This has consequences for effectively bringing down local air quality issues, especially in low emission zones (LEZ). This paper presents a review of the European emission regulation history up to date and makes a comparison with the approach in the other important car markets globally. One can conclude that a substantial update of the European regulatory framework concerning automotive emissions is required, while ambitious post-2021 targets should be set if Europe does not want its automotive industry to lose its competitive position in the global market. In addition, an equilibrium should be sought for between sustainable personal transport in the form of zero-emission vehicles (ZEV), and a sustainable economic climate for the automotive industry. The former is needed if LEZs are to effectively bring down pollutant levels in cities.
Thermal management is crucial for improving the charge–discharge efficiency and cycling life of lithium ion battery. In this paper, a mathematical model coupling electronic conduction, mass transfer, energy balance and electrochemical mechanism is developed. Lithium ion diffusivity and chemical reaction rate of cathode material are estimated by comparing simulated results with experimental data of pulse test at various current charge–discharge rates (0.2C, 0.5C, 1C, 2C) and operating temperatures (0°C, 10°C, 25°C, 55°C). The modeling results are further validated in aspects of electrochemical performance, thermal performance and electrochemical-thermal coupling effects, which show well agreement between the modeling results and experimental results. The modeling results show that lithium ion concentration gradient in both liquid phase and solid phase are greatly affected by temperature, and the lithium ion concentration gradient increase when temperature decrease. This phenomenon results in the capacity losses and power loses of lithium ion battery during low temperature operation. The reversible heat generation during charging process is equal with the heat consumption during discharging process. It is also indicated that the reversible heat is dominant at low rate discharging process and irreversible heat is dominant at high rate discharging process. Proper cooling system should be added to keep battery temperature within safety range during high rate current charging/discharging.
Lithium–sulphur batteries are among the most promising systems for the next generation of rechargeable lithium batteries. Whereas a wide range of factors contribute to the overall performance of the Li–S system, reported optimization procedures typically focus on the development of novel structured cathodes. Here, the importance of often-neglected experimental parameters contributing to the performance of Li–S systems is demonstrated. Specifically, the effects of varying the amount of electrolyte, the salt concentration and the type of electrolyte additive are presented and factors that improve cycling stability are discussed. Some of the parameters, such as sulphur-particle size and the type of conductive additive used in the electrodes, affected the cell's performance less than might be expected. Long-term cycling (up to 500 cycles) with a low amount of electrolyte is demonstrated. Our results suggest that parameters related to the electrolyte are more important for improving the overall performance than those concerning the electrode structure.
A new controlled test method has been developed to simulate the occurrence of internal short in Li-ion cells. Two different internal short kinds namely aluminum shorting to anode and cathode shorting to anode has been studied with this test method at several states of charge. Infra-red imaging technique has been adopted to analyze the thermal propagation for both the short kinds. As a comparison, the most commonly adopted nail penetration test was also conducted and analyzed using IR-imaging. The instantaneous rise in temperature referred as temperature spike upon incurring internal short was able to be captured using the IR imaging for the anode–aluminum short kind and the magnitude of such temperature spike was found to be proportional to SOC of the cell.
MnO@C nanocomposites are synthesized by annealing MnO microspheres treated with oleic acid as carbon source. The obtained MnO@C nanocomposites exhibit a discharge capacity of 1075 mAh/g for the initial cycle, and show the excellent cycling performance with a discharge capacity of 421 mAh/g after 100 cycles at a current density of 100 mA/g. The total specific capacity of MnO@C nanocomposites is higher than those of pure MnO microspheres in our experiments. Owing to the superior electrochemical behavior, the as-obtained MnO@C nanocomposites are potentially applied as next-generation anode material for lithium-ion batteries.
The high lithium conductivity of argyrodite Li6PS5Cl makes it an attractive candidate as solid electrolyte in all solid-state Li batteries. Aiming at an optimal preparation strategy the structure and conductivity upon different mechanical milling times is investigated. Li6PS5Cl material with high ionic conductivity of 1.1·10−3 S/cm was obtained by milling for 8hours at 550rpm followed by a heat-treatment at 550°C. All solid-state Li-S batteries were assembled, combining the Li6PS5Cl solid electrolyte, with a carbon-sulfur mixture as positive electrode and Li, Li-Al and Li-In as negative electrode. An optimum charge/discharge voltage window between 0.4 and 3.0V vs. Li-In was obtained by CV experiments and galvanostatic cycling displays a very large capacity around 1400 mAh/g during the first cycles, decreasing below 400 mAh/g after 20 cycles. Impedance spectroscopy suggests that the origin of the capacity fading is related to an increasing electrode-electrolyte interface resistance.
Global environmental concerns, increasing energy demands and developments in renewable energy technologies present a new possibility to implement renewable energy sources. Solar energy is the most prominent among renewable sources, as it is an inexhaustible resource and its exploitation has thus far been ecologically friendly. The potential amount of solar energy is considerably greater than current worldwide energy demands. Solar energy has been developing more rapidly than the other renewable energy sources for the last few decades. The best way to harvest the sun’s power is photovoltaic (PV) technology. This paper presents a study on solar energy in the form of a stand-alone and hybrid power generation system used to electrify off-grid locations. The stand-alone solar-PV system developed here is intended to be used to power a single house or a small community and it also functions as a mini-grid, generating power in places where adequate solar radiation is available throughout the year. However, many places throughout the world experience unsteady amounts of solar radiation and in those places, a hybrid solar-PV system is the most efficient solution for electrification. The main benefit of the hybrid system is that the weakness of one source is covered by the other source. This paper also presents some comparative case studies, project examples and demonstrations of stand-alone solar and hybrid solar systems implemented at various locations throughout the world over the last twelve years.
Accurate state of charge estimation of lithium-ion battery is directly related to the safe operation of electric vehicles and also an indispensable function of the battery management system. Four aspects of efforts are made to improve the estimation accuracy. First, for overcoming the drawbacks of equivalent circuit model and electrochemical model, the fractional order impedance model is built via electrochemical impedance spectroscopy data and the fractional element is used to describe the polarization effect in a simple and meaningful way. Second, the discrete state-space equations of the impedance model are inferred by Grünwald-Letnikov definition and parameters of the model including the order of the fractional element are identified together by genetic algorithm (GA) and the experiment data of the dynamic driving cycles. Third, the fractional order unscented Kalman filter technique is presented and the ‘short memory’ technique is employed to improve the computation efficiency of fractional operator. Lastly, experimental validation is implemented to verify the effectiveness of the proposed approach and results show that the SoC estimation accuracy can be improved by the proposed model and estimation method. The estimation error can be controlled within the range of 3%.
Abstract The purpose of this study was to test the sustained impact of a 6-month diabetes management intervention in middle-aged and older adults with schizophrenia and type 2 diabetes mellitus. Method Fifty-two individuals, over the age of 40 completed both baseline and 12-month follow-up assessments. Results At 12months, Diabetes Awareness and Rehabilitation Training (DART) participants experienced significantly greater improvement in body mass index, waist circumference and diabetes knowledge than did the Usual Care Plus Information (UCI) group. No improvements were found for A1C or energy expenditure. Conclusions Results suggest that DART promotes lasting changes in health parameters that are maintained after treatment ends.
This paper describes the design and testing of a 10kWp photovoltaic (PV) system and summarizes its performance results after the first 6 months of operation. This system functions as a stand-alone power system that is used to supply electricity for isolated buildings and is designed for integration with a micro-grid system (MGS), which is the future concept for a renewable energy-based power network system for Thailand. The system is comprised of the following components. An array with three different types of PV modules consisting amorphous thin film of 3672W, polycrystalline solar cell of 3600W and hybrid solar cell of 2880W, making up a total peak power of 10.152kW. In addition, there are three grid-connected inverters of 3.5kW each, three bi-directional inverters of 3.5kW each and an energy storage system of 100kWh. After the first 6 months of system operation, it was found that all the components and the overall system had worked effectively. In total, the system had generated about 7852kWh and the average electricity production per day was 43.6kWh. The average efficiency of amorphous thin film panel, polycrystalline panel, hybrid solar cell panel and entire PV panel system was 6.26%, 10.48%, 13.78% and 8.82%, respectively. From the analysis of the daily energy production, daily energy consumption and energy storage, the results seem to indicate that there was some mismatching between energy supply and demand in the system. However, this can be overcome by integrating the system to a micro-grid network whereby the energy from the system can be diverted to other loads when there is a surplus and additional energy can be drawn from external sources and fed to the system when the internal supply is insufficient.
An expert panel replies to questions on lead-acid technology and performance asked by delegates to the Ninth Asian Battery Conference. The subjects are as follows. Grid alloys: effects of calcium and tin levels on microstructure, corrosion, mechanical and electrochemical properties; effect of alloy-fabrication process on mechanical strength and corrosion resistance; low dross-make during casting of lead–calcium–tin alloys; future of book-mould casting; effect of increasing levels of silver; stability of continuously processed grids at high temperature. Negative-plate expanders: function of lignosulfonates and barium sulfate; benefits of pre-blended expanders; optimum expander formulations. Valve-regulated batteries: effect of oxygen cycle; optimum methods for float charging; charging and deep-cycle lifetimes; reliability testing.
In this work the heat generation in porous LiCoO2 based electrodes for lithium ion batteries is studied in detail. Irreversible heat generation rates due to ohmic resistance, charge transfer and mass transport limitations as well as the reversible heat of the electrode reaction are determined from electrochemical measurements as a function of the C-rate, the temperature and the lithium concentration in the active material. The results show that all the individual heat sources contribute significantly to the total heat generation in the electrode. The heat sources are functions of the C-rate and the temperature as well as the lithium concentration in the active material. The reversible heat contribution was found to be most significant at higher temperatures und lower C-rates, which tend to reduce kinetic limitations and irreversible heats, respectively. The heat generation rate due to mass transport limitations is most influential among the irreversible heats, whereas the ohmic contribution shows a minor impact. The total heat generation was found to increase with increasing C-rate and decreasing temperature. Furthermore, the heat generation is significantly reduced for charging compared to discharging due to the intrinsic asymmetry of the reversible heat and larger kinetic limitations for lithiation compared to delithiation of LiCoO2.
Heteroatom modification represents one of the largest studied areas of research related to nanostructured carbon materials, with integrated applications stretching from energy production and storage to sustainability and medical uses. While a wide variety of dopants (boron, phosphorus, iodine, fluorine, etc.) have been studied, doping carbon structures with nitrogen ad-atoms has arguably experienced the greatest progress and brought the most attention over the last several years. Research in this field has conclusively demonstrated that nitrogen doping is an effective way to tailor the properties of carbon and tune the material for various applications of interest. This review provides a comprehensive overview of advances in the last half decade on state-of-the-art carbon modification with nitrogen heteroatoms. Improvements in well-established fabrication/modification processes are discussed as well as novel strategies. Additionally, recent theoretical and experimental findings related to the benefits and effects of nitrogen modification for specific applications in the energy and environmental fields are reviewed.
The 25 years have provided a number of lessons. Social audit reduces the arbitrariness of planning decisions, and reduces the wastage of simply allocating resources the way they were in past years. But too much evidence easily exceeds the uptake capacity of decision takers. Political will of governments often did not match those of donors with interest conditioned by political cycles. Some reforms have a longer turnaround than the political cycle; short turnaround interventions can develop momentum. Experience and specialisation made social audit seem more simple than it is. The core of social audit, its mystique, is not easily taught or transferred. Yet teams in Mexico, Nicaragua, Canada, southern Africa, and Pakistan all have more than a decade of experience in social audit, their in-service training supported by a customised Masters programme.