In this paper, the characteristics analysis results of lithium-ion battery show that the essence of the inconsistency of lithium-ion battery is State-Of-Charge (SOC) inconsistency. Therefore, the ...disparity of SOC can be used to describe the battery inconsistency degree and investigate the equalization control strategy of lithium-ion battery. Firstly, Extended Kalman Filter (EKF) algorithm is proposed to estimate the SOC on the basis of the Ampere-Hour integral and open circuit voltage. Then, the Simscape battery model is established to estimate battery parameters, and the HPPC experiment is employed to verify the SOC estimation precision. Moreover, based on the battery SOC inconsistency laws, the battery equalization control strategy is presented. Finally, the experimental bench is set up to validate the effectiveness of the equalization strategies. Simulation results depict that with the active equalization, the dispersion of SOC drops from 9.4% to 0.84% during charging phase, while the dispersion of SOC drops from 7.4% to 4.12% and the dispersion of voltage drops from 8.54% to 0.71% during discharging phase. The experimental results show that the maximum SOC estimation error is about 4%, so this SOC estimation method meets the accuracy requirement; the 6 batteries are fully charged at the same time with charging equalization, the voltage error is within 15 mV and the voltage variance is within 2%; discharging processes of the 6 batteries are over at the same time with discharging equalization, voltage error is below 15 mV and the voltage variance is below 2%. These results indicate that active equalization control in this paper not only can improve cell inconsistency but also can improve the energy utilization of the battery pack in the process of charging and discharging.
•Disparity of State-Of-Charge is used to describe the degree of battery inconsistency.•Equalization control strategy of lithium battery is investigated and proposed.•Extended Kalman Filter algorithm is proposed to estimate the State-Of-Charge.•Simscape battery model is established to estimate battery parameters.
Under-water and unidirectional air penetration, viz. air "diode", was effectively achieved on the basis of a composite mesh with Janus wettability. In the aqueous solution, the air bubbles can only ...pass through the mesh from the hydrophilic side to the superhydrophobic side, whereas they will be blocked from the opposite direction.
On the occasion of the 40th anniversary of reform and opening up, the Central Committee of the Communist Party of China (CPC) made a decision on regional strategic layout, introduced the Guiding ...Opinions of the CPC Central Committee and the State Council on Supporting Hainan in Comprehensively Deepening Reform and Opening Up (hereinafter referred to as the Guiding Opinions), and decided to support Hainan island in developing into a pilot free trade zone (FTZ), gradually promoting the establishment of a free trade port with Chinese characteristics. Such decisions have two significant implications: (1) It marks the official establishment of a free trade port with Chinese characteristics, which is a new mode of reform and opening up under the new situation; (2) It indicates that the construction of the Hainan Pilot FTZ is a means for opening up in the practice of Chinas national conditions and legal framework. Since Hainan is the only pilot FTZ that includes rural areas and agriculture, it faces several problems such as the unbalanced regional development, low level of economic development, prominent Three Rural Issues, and weak industrial base. Therefore, as the 12th pilot FTZ in China, the construction of Hainan pilot FTZ is quite different from the other 11 pilot FTZs. In other words, Hainan pilot FTZ should not only learn from the successful experience of the other 11 pilot FTZs, but also realize the differences to implement an aggressive reform. The Hainan pilot FTZ can gradually become a new benchmark for a comprehensively deepening reform and opening up in the new era only by exploring various reform measures in line with China's national conditions and its practical development orientation, and implementing these reform measures gradually.
Continuous grasping force estimation based on electromyography (EMG) signals, is very useful in practical applications including prosthetic control and human force observation. However, implementing ...the practical grasping force estimation usually considers a trade-off between the computational precision and resources. Specifically, the estimation based on the Huxley-type muscle model reaches detailed approximation of physiological process at a cost of larger computational resources for solving nonlinear partial differential equations while the counterpart with a traditional Hill-type muscle model. In this article, we achieve the grasping force estimation based on a reduced Huxley-type musculoskeletal model with high accuracy yet low time delay. Leveraging on a balanced truncation method, we further reduce the dimensionality of the spectral method solution in the Huxley-type musculoskeletal model for the model simplification. In addition, we introduce the Kalman filter method to process the EMG signals obtained by an armband, yielding better real-time performances and accuracy compared to the signal treatment using the traditional EMG filter method. Moreover, we also implement an effective identification of the model parameters using a particle swarm method. Finally, we trained the model on the first day and made grasping force estimation experiments involved with three participants over the course of a month. We envision that this effective and practical method would further improve the practical applications in the field of grasping force estimation.
IMPACT 2002+ normalized end-point scores of each section in MEC system Effect of MEC performance parameters on GWP.
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•A life cycle assessment of a microbial electrolysis cell for ...hydrogen production is performed.•Ecoinvent database is used as the compliant data source for life cycle assessment.•Microbial electrolysis cell system is designed based on the existing pilot plants.•Impact of microbial electrolysis cell performance parameters on life cycle results is analyzed.
An environmental life cycle assessment of a pilot scale microbial electrolysis cell for hydrogen production was performed for the first time in this study. The microbial electrolysis cell system was designed based on the existing pilot plants with urban wastewater flow rate of 65 L·d−1 at wastewater strength of 500 mg COD·L−1. The effect of the performance parameters of the microbial electrolysis cell on life cycle results was analyzed with SimaPro 8.2.3.0. The results showed that the emissions per kg hydrogen-produced from construction phase are the greatest among all phases of the current microbial electrolysis cell system. An increase in cathodic gas recovery and hydrogen production rate resulted in a decrease in emissions per kg hydrogen-produced from the operation and construction of the microbial electrolysis cell. In addition, the total life cycle emissions decreased with increasing of the cathodic gas recovery and electricity transformation efficiency, and increase with increasing applied voltage. The global warming potential from the operation phase was 18.8 kg carbon dioxide-eq/kg hydrogen under the following conditions: applied voltage of 0.5 V, electricity transformation efficiency of 90%, and cathodic gas recovery of 90%. Compared with existing hydrogen production and wastewater treatment technologies, the current microbial electrolysis cell technology for hydrogen production from wastewater can still be improved in terms of environmental benefits and technical maturity. Nevertheless, microbial electrolysis cell technology with optimized operation parameters will hopefully become an important choice of hydrogen production and wastewater treatment technology in the future.
Achieving a well tradeoff between electrical and optical performances remains challenging for conventional silver nanowires (AgNWs) random network conductors. An innovative AgNW‐bundle mesh (AgBM) ...composed of exquisite knots and abundant open area is realized by one‐step spray‐assembly at room temperature, showing high optoelectronic performance. A dynamic assembly mechanism based on the spray assembly of isopropanol‐based AgNWs ink is revealed, ensuring a favorable coffee‐ring effect dominated by the capillary flow rather than Marangoni reflux, driving the AgNWs to deposit at the edges of droplets. The initially formed AgNW‐bundle rings serve as template to constrain the movement of AgNWs from the subsequent droplets, rendering scalable and continuous accumulation of nanowires to produce a connective AgBM. The controlling factors of surface tension of substrates and ink, wettability, spreading and pinning effect of the ink droplets, as well as tunable assembly driving force determined by spraying rate are revealed, realizing an universal spray‐assembly strategy for tailorable fabrication of AgBMs using AgNWs with different sizes in diameter (20–120 nm) and length (20–200 µm). Thicker AgBMs could reduce the sheet resistance without severe sacrifice of transparency. Thinner AgNW‐bundles/knots with better electrical connection can be realized from the finer and longer AgNWs, delivering higher optoelectronic performance.
A dynamic spray‐assembly mechanism of silver nanowires‐bundle mesh (AgBM) is revealed, indicating pinned ink‐droplets with a favorable coffee‐ring effect is important for the scalable and continuous accumulation of nanowires at the edges of droplets, producing a connective AgBM for high‐performance flexible transparent conductor. Surface tension, wettability, and spraying rate are controllable for a tailorable spray‐assembly strategy universal for various AgNWs.
•Simulation-based multi-scale statistical analysis of stress and strain reveals the prevailing statistical distributions.•The fundamental origins of local strain and stress statistics are ...identified.•The statistical method is seen to give guidance for rational design for structural integrity.
Multiscale stresses and strains in polycrystalline metals are always inhomogeneous. In this study, a rate-independent crystal plasticity formulation was implemented for a cubic representative volume element (RVE) of an fcc polycrystal generated by 3D Delaunay tessellation. Multiple realizations were generated with crystallographic orientation permutations and different grain morphologies in order to investigate the statistical distribution of stress, elastic lattice strain and total strain at the macro-, meso- and micro-scale. Macroscopically, at 1.55% total strain (elasto-plastic deformation), the overall stress statistics among different RVEs were observed to follow a normal distribution, whose profile shape is affected by the parameters that describes the lognormal grain size distribution. On the mesoscale, the orientation-specific elastic strains were accurately reproduced via the use of diffraction post-processing and validated by neutron diffraction data for a polycrystalline alloy. Microscopically, the local elastic strains (and hence stresses) universally follow a normal distribution, while plastic strains follow a lognormal probability distribution. Reliable knowledge of the statistical distributions of stresses and strains give new guidance for the determination of the minimum RVE size. The above finding reveals the nature of stress and strain inhomogeneity at multiple scales and emphasizes the fact that the dispersion of local stress and strain is much larger than that of the macroscopic average. The statistical analysis of stress and strain distribution at multiple scales provide further rich insights into the connection between microstructure and mechanical properties under monotonic and cyclic loading.
Sodium ion batteries (SIBs) are promising alternatives to lithium ion batteries with advantages of cost effectiveness. Metal sulfides as emerging SIB anodes have relatively high electronic ...conductivity and high theoretical capacity, however, large volume change during electrochemical testing often leads to unsatisfactory electrochemical performance. Herein bimetallic sulfide Cu2MoS4 (CMS) with layered crystal structures are prepared with glucose addition (CMS1), resulting in the formation of hollow nanospheres that endow large interlayer spacing, benefitting the rate performance and cycling stability. The electrochemical mechanisms of CMS1 are investigated using ex situ X‐ray photoelectron spectroscopy and in situ X‐ray absorption spectroscopy, revealing the conversion‐based mechanism in carbonate electrolyte and intercalation‐based mechanism in ether‐electrolyte, thus allowing fast and reversible Na+ storage. With further introduction of reduced graphene oxide (rGO), CMS1–rGO composites are obtained, maintaining the hollow structure of CMS1. CMS1–rGO delivers excellent rate performance (258 mAh g−1 at 50 mA g−1 and 131.9 mAh g−1 at 5000 mA g−1) and notably enhanced cycling stability (95.6% after 2000 cycles). A full cell SIB is assembled by coupling CMS1–rGO with Na3V2(PO4)3‐based cathode, delivering excellent cycling stability (75.5% after 500 cycles). The excellent rate performance and cycling stability emphasize the advantage of CMS1–rGO toward advanced SIB full cells assembly.
Bimetallic Cu2MoS4 (CMS) hollow nanospheres (CMS1) are obtained by modified solvothermal reactions. CMS1 delivers notably improved rate performance than CMS in ether‐electrolyte, in which an intercalation‐dominant electrochemical reaction mechanism is revealed. With further incorporation of reduced graphene oxide (rGO), the CMS1–rGO composites deliver excellent cycling stability, allowing fast and stable Na+ storage in full cell by coupling with an optimized Na3V2(PO4)3 cathode.
Nanostructured thin films are important in the fields of energy conversion and storage. In particular, multi-layered nanostructured films play an important role as a part of the energy system for ...energy saving applications in buildings. Inkjet printing is a low-cost and attractive technology for patterning and deposition of multi-layered nanostructured materials on various substrates. However, it requires the development of a suitable ink formulation with optimum viscosity, surface tension and evaporation rate for various materials. In this study, a versatile ink formulation was successfully developed to prepare NiO and WO3 nanostructured films with strong adhesion to ITO coated glass using inkjet printing for energy saving electrochromic applications. We achieved a high performance electrochromic electrode, producing porous and continuous electrochromic films without aggregation. The NiO film with 9 printed layers exhibits an optical modulation of 64.2% at 550 nm and a coloration efficiency (CE) of 136.7 cm(2) C(-1). An inkjet-printed complementary all solid-state device was assembled, delivering a larger optical modulation of 75.4% at 633 nm and a higher CE of 131.9 cm(2) C(-1) among all solid-state devices. The enhanced contrast is due to the printed NiO film that not only performs as an ion storage layer, but also as a complementary electrochromic layer.
The rational design and scalable assembly of nanoarchitectures are important to deliver highly uniform, functional films with high performance. However, fabrication of large-area and high-performance ...films is quite difficult because of the challenges in controlling homogeneous microstructures, interface properties, and the high cost of the conventional vacuum deposition technique. Here, we report a solution-processed molecular level assembly approach to fabricate self-supported (without any binders or conductive additives) large-area (up to 810 cm2) functional films with controllable thickness and high homogeneity. We show that the assembled prototypical Fe(II)-based metallo-supramolecular polymer (polyFe) film exhibits unprecedented electrochromic performance such as ultrahigh coloration efficiency (750.3 cm2 C–1), fast switching speed (<1 s), as well as robust electrochemical stability (with no obvious degradation after 10 000 cycles). We further demonstrate that the assembled polyFe films can be used to fabricate a smart energy-storage indicator, in which the energy-storage level is visually perceptible and recognizable in real time. This strategy provides an exciting alternative route for highly scalable fabrication of uniform films and may extend to other materials for a wide range of functional devices of diverse applications.
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