Working Temperature Research Articles

Compensación cinética y termodinámica del pardeamiento no enzimático de zumos clarificados de limón

This paper presents a study on kinetic and thermodynamic compensation to evaluate the kinetics of non-enzymatic browning of clarified lemon juices. In a previous work, the kinetic constants of browning were presented using the evolution of the absorbance at 420 nm (A420) and luminosity (L*) for different soluble solids contents (64.6; 50; 35; 20 and 10 ºBrix) and different working temperatures (70, 80, 90 and 95 ºC). The parameters of the Arrhenius equation were obtained by fitting the kinetic constants and temperatures. The variation of lnK0 with Ea follows a linear trend, so there is kinetic compensation, with isokinetic temperature values being 126.6 ºC and 149.7 ºC for A420 and L*, respectively. The transition state equilibrium constants were determined using the Eyring equation for each soluble solids content and each temperature. The equilibrium constants were adjusted to the Van't Hoff equation and the set of pairs of estimated values for the activation enthalpy and the activation entropy also followed a straight line, which causes thermodynamic compensation, with isoequilibrium temperatures of 112.8 ºC and 136.3 ºC for A420 and L*, respectively. It was concluded that the browning mechanism is the same for the ranges of soluble solids content and temperature studied. Since all isokinetic and isoequilibrium temperatures were higher than the working temperature values, it was also concluded that the control was enthalpic for all cases. To avoid the deterioration of these juices, it is advisable to intervene in the working temperature, trying to ensure that the heat treatment is carried out at the lowest possible temperature.

Observation of Hydrostatic‐Pressure‐Modulated Giant Caloric Effect and Electronic Topological Transition

AbstractPhase transition is a fundamental phenomenon in condensed matter physics, in which states of matter transform to each other with various critical behaviors under different conditions. The magnetic martensitic transformation features significant multi‐caloric effects that benefit the solid‐state cooling or heat pumping. Meanwhile, the electronic topological transition (ETT) driven by pressure has been rarely reported in martensitic systems. Here, the modulation effects of hydrostatic pressure on phase transitions in a magnetic martensitic alloy are reported. Owing to the huge volume expansion during the transition, the martensitic transition temperature is driven from 339 to 273 K by pressure within 1 GPa, resulting in highly tunable giant baro‐ and magneto‐caloric effects (BCE and MCE) in a wide working temperature range. Interestingly, an ETT is further induced by pressure in the martensite phase, with a sudden drop of the measured saturation magnetization around 0.6 GPa. First‐principles calculations reveal a sharp change in the density of states (DOS) due to the orbit shift around the Fermi level at the same pressure and reproduce the experimental observation of magnetization. Besides, the ETT is accompanied by remarkable changes in the lattice parameters and the unit‐cell orthorhombicity. The study provides insight into pressure‐modulated exotic phase‐transition phenomena in magnetic martensitic systems.

Work hardening and X-ray diffraction studies on ASS 304 at high temperatures

Abstract One of the most common characteristics of metallic alloys is work hardening, which is most beneficial as it is the primary reason for the alloys’ tenacity to withstand loading even in the presence of internal flaws or geometrical errors. Thus, the work hardening coefficient gives the maximum amount of homogeneous plastic deformation in tensile straining. Thus, complex-forming operations are facilitated by a high coefficient without experiencing premature failure. Naturally, work hardening has a significant impact on the mechanical energy required to shape a material by plastic deformation, such as rolling, forming, etc. The quantity of energy that the material stores during plastic deformation is also managed by work hardening. As a result, it significantly influences how the metal behaves when it is subsequently softened during annealing. Finally, the hardening capacity and durability of the work hardened state are significant practical challenges because many high-volume stretch formed components are directly used. Typically, the current study begins, at homologous temperatures above 0.4 times melting point, with a description of work hardening at 700, 800, and 900°C temperatures in three different orientations with respect to rolling direction R 0, R 45, and R 90 and 10−1−10−3 s−1 strain rates, where thermally triggered processes exhibit a prominent role in work hardening. Three stages of behavior were identified by analyzing the tensile work hardening of ASS 304 steel. Dynamic strain aging is the cause of the anomalous fluctuation in the work hardening rate that is seen in hot working temperatures. X-ray diffraction examination is conducted to introspect any phase changes occurring in hot working regions improving plasticity of ASS 304.

Stretch-forming characteristics of austenitic material stainless steel 304 at hot working temperatures

Abstract The need for sheet metal forming using highly resistant materials such as titanium alloys and stainless steel has increased recently. These materials possess elevated mean flow stress values, which make them difficult to draw at room temperature. To achieve a homogeneous distribution of strain in the stretched component, reduce the load required for plastic deformation, and greatly improve material formability, hot forming is helpful. The goal of the current study is to conduct stretch-forming experiments to investigate the forming characteristics of Austenitic material Stainless Steel (ASS) 304 at Hot working temperatures. Stretch forming experiments have been conducted on the Servo electrical sheet press test machine at 650 and 800°C. The formability has been estimated by constructing a Fracture forming diagram (FFLD), limiting the height of the dome (LDH) and the distribution of the strain of stretched cups. It has been discovered that the limit of forming bounds rises with the temperature reaching 800°C, while the DSA effect causes the necking region – the area between the safe and fracture limits ‒ to decrease with additional temperature rise from 800 to 900°C. Within the experimental limitations, it has been considered that the Hot forming of ASS 304 at 650°C gives the highest strain forming limits with a uniform strain distribution in the stretched cups. From the Formability limit diagram, dome height, and strain distribution, it can be observed that ASS 304 has good limiting strain up to 800°C with lower load application.

Reviving Cost-Effective Organic Cathodes in Halide-Based All-Solid-State Lithium Batteries.

The evolution of inorganic solid electrolytes has revolutionized the field of sustainable organic cathode materials, particularly addressing the dissolution problems in traditional liquid electrolytes. However, current sulfide-based all-solid-state lithium-organic batteries still face challenges such as high working temperatures, high costs, and low voltage. Here, we design an all-solid-state lithium battery based on a cost-effective organic cathode material phenanthrenequinone (PQ) and a halide solid electrolyte Li2ZrCl6. Thanks to the good compatibility between PQ and Li2ZrCl6, the PQ cathode achieved a high specific capacity of 248 mAh g-1 (96% of the theoretical capacity), a high average discharge voltage of 2.74 V (vs. Li+/Li), and a good capacity retention of 95% after 100 cycles at room temperature (25 °C). Furthermore, the interaction between the high-voltage carbonyl PQ cathode and both sulfide and halide solid electrolytes, as well as the redox mechanism of PQ cathode in all-solid-state batteries, were carefully studied by a variety of advanced characterizations. We believe such a design and the corresponding investigations for the underlying chemistry give insights into the further development of practical all-solid-state lithium-organic batteries.

Reviving Cost‐Effective Organic Cathodes in Halide‐Based All‐Solid‐State Lithium Batteries

The evolution of inorganic solid electrolytes has revolutionized the field of sustainable organic cathode materials, particularly addressing the dissolution problems in traditional liquid electrolytes. However, current sulfide‐based all‐solid‐state lithium‐organic batteries still face challenges such as high working temperatures, high costs, and low voltage. Here, we design an all‐solid‐state lithium battery based on a cost‐effective organic cathode material phenanthrenequinone (PQ) and a halide solid electrolyte Li2ZrCl6. Thanks to the good compatibility between PQ and Li2ZrCl6, the PQ cathode achieved a high specific capacity of 248 mAh g‐1 (96% of the theoretical capacity), a high average discharge voltage of 2.74 V (vs. Li+/Li), and a good capacity retention of 95% after 100 cycles at room temperature (25 °C). Furthermore, the interaction between the high‐voltage carbonyl PQ cathode and both sulfide and halide solid electrolytes, as well as the redox mechanism of PQ cathode in all‐solid‐state batteries, were carefully studied by a variety of advanced characterizations. We believe such a design and the corresponding investigations for the underlying chemistry give insights into the further development of practical all‐solid‐state lithium‐organic batteries.

Review on preheating systems for Lithium-ion batteries of electric vehicles under low temperature circumstance

Nowadays, energy and environmental protection issues have become the focus of most attention. The development of electric vehicles which depends on lithium ion battery as power source is one of the most applicable way in dealing with these issues. Lithium-ion battery (LIB) is highly favoured for its outstanding features in energy density, cycle life and energy retention. However, its severe sensitivity to working temperatures leads to problems when driving electric vehicles. Therefore, researchers and engineers have explored approaches to guaranteeing a suitable working temperature for LIB, one of which is the battery preheating system. To clarify the advancement of this system, both internal and external preheating methods studied in recent years are summarized, and the discussion for future research is included.

Hydrothermal Synthesis of SnO2 with Different Morphologies as Sensing Materials for HCHO Detection.

Morphology regulation is an effective strategy for improving the sensor sensitivity of transition metal oxide nanostructures. In this work, SnO2 with three different morphologies (nanorods, nanoparticles, and nanopillars) has been synthesized by a simple one-step solvothermal process with the addition of various solute ratios at 180 °C for 6 h for detecting formaldehyde (HCHO) at the optimum working temperature of 320 °C. Compared to nanorods and nanopillars, the created SnO2 nanoparticles exhibit a much faster response time and sensitivity than other samples, showing the fastest recovery time (18 s) with the highest sensitivity of 6-100 ppm of the HCHO gas. The sensing mechanism of the sensors is investigated by Brunauer-Emmett-Teller (BET) methods and X-ray photoelectron spectroscopy (XPS) analysis, revealing that the pore size distribution and amount of OV and OC improve the charge transfer and HCHO adsorption of nanoparticle sensors. Such an effect of morphology control on sensing performance paves an idea for the development of different structure-based HCHO sensors.

Optimal charging for lithium-ion batteries to avoid lithium plating based on ultrasound-assisted diagnosis and model predictive control

Lithium plating in lithium-ion batteries for electric vehicles, occurring due to low-temperature or high-rate charging, is a significant factor impacting safety and service life. To address this issue, a novel adaptive charging approach is proposed, combining ultrasound-assisted diagnosis and model predictive control (MPC). In the method, a discrete state-space electrochemical model is used to describe the dynamic characteristics of the battery, and a model predictive controller (MPC) is utilized to optimize the charging current to avoid lithium plating. Considering that factors such as battery performance degradation and variable working temperature affect the battery model's judgment of lithium plating, an ultrasound-assisted diagnosis method is used to determine the critical point of lithium plating. The effectiveness of the method is validated through low-temperature charging and cycle aging experiments. The results indicate that without complex model parameter calibration in different temperatures, the new charging method not only has a higher charging speed than constant current charging, but also can effectively suppress the occurrence of lithium plating on the negative electrode of the battery. The method is expected to be applied in electrochemical energy storage systems to enhance safety and service life.

Adsorption and gas sensitivity properties of graphene and Rh-decorated graphene towards SF6 decomposed gases: A DFT study

In order to solve the serious threat of SF6 decomposed gases (H2S, SO2, SOF2, SO2F2) to the stable operation of electrical equipment. In this study, the geometric structure, adsorption energy, density of states (DOS), sensitivity based on band structure and recovery time of H2S, SO2, SOF2, SO2F2 on graphene and Rh-modified graphene (Rh-graphene) were investigated computationally by density functional theory (DFT). The geometric structure of Rh-graphene was optimized with an average Rh-C bond length of 1.891 Å. According to the analysis of DOS and band structure, the electrical conductivity has a little effect of the Rh-graphene compared with pristine graphene, but Rh modification can regulate the band gap of graphene. The adsorption energy (Ead) and the sensitivity (S) at work temperature indicate that graphene has ideal adsorption and sensing properties for SO2 and Rh-graphene reflects the excellent applicability as the SO2 and SO2F2 gases sensor with the sensitivity of approximately −99 % and −60 %, respectively. The Graphene/SO2 system owns the minimum recovery time of 2154.3 ps. The recovery time of Rh-graphene/H2S and SOF2 is several orders of magnitude smaller than Rh-graphene/SO2 and SO2F2. The analysis of DOS and band structure was used to explain the sensing mechanism. The study would lay a theoretical foundation for the development of SF6 decomposed gases sensor for electrical equipment insulation.

Direct reconstruction of the temperature field of lithium-ion battery based on mapping characteristics

Lithium-ion (Li-ion) batteries are susceptible to the working temperature so that the monitoring is essential to the battery internal temperature. The electrochemical-thermal coupling model completely reflects the battery internal behavior. However, the high complexity and multi-field coupling make it difficult to be applied to reconstruct the battery temperature field based on state observer. Based on mapping characteristics, this work proposes a temperature field direct reconstruction scheme. And the electrochemical-thermal coupling model plays a large role in this scheme. Mapping characteristic vectors of the transient temperature field are obtained from the step response model of the Li-ion battery temperature field to charge and discharge current. Furthermore, the quantitative connection of the mapping characteristic vectors between the surface points of and the internal nodes of the battery is characterized by a relevance degree matrix. And a direct reconstruction model of the internal transient temperature field is established. The internal temperature field is reconstructed directly online and in real time via exploiting the temperature measurements on battery surface. In numerical experiments, the three-dimensional temperature field of the Li-ion battery charge and discharge processes is reconstructed. The effects of charge and discharge rates, model mismatch, and measurement errors on the reconstruction results are investigated. During the charge and discharge processes, the maximum values of the transient average error of the reconstructed temperature field are about 0.4 K and 0.3 K, respectively. And the transient average error is generally below 0.8 K when the standard deviation of measurement errors is 0.5 K.

Ultrathin Boundary-Less SnO2 Films with Surface-Activated Two-Dimensional Nanograins Enable Fast and Sensitive Hydrogen Gas Sensing.

Fast and reliable semiconductor hydrogen sensors are crucially important for the large-scale utilization of hydrogen energy. One major challenge that hinders their practical application is the elevated temperature required, arising from undesirable surface passivation and grain-boundary-dominated electron transportation in the conventional nanocrystalline sensing layers. To address this long-standing issue, in the present work, we report a class of highly reactive and boundary-less ultrathin SnO2 films, which are fabricated by the topochemical transformation of 2D SnO transferred from liquid Sn-Bi droplets. The ultrathin SnO2 films are purposely made to consist of well-crystallized quasi-2D nanograins with in-plane grain sizes going beyond 30 nm, whereby the hydroxyl adsorption and grain boundary side-effects are effectively suppressed, giving rise to an activated (101)-dominating dangling-bond surface and a surface-controlled electrical transportation with an exceptional electron mobility of 209 cm2 V-1 s-1. Our work provides a new cost-effective strategy to disruptively improve the gas reception and transduction of SnO2. The proposed chemiresistive sensors exhibit fast, sensitive, and selective hydrogen sensing performance at a much-reduced working temperature of 60 °C. The remarkable sensing performance as well as the simple and scalable fabrication process of the ultrathin SnO2 films render the thus-developed sensors attractive for long awaited practical applications in hydrogen-related industries.

The impact of CBz-PAI interlayer in various HTL-based flexible perovskite solar cells: A drift-diffusion numerical study

In perovskite solar cells (PSCs), the charge carrier recombination obstacles mainly occur at the ETL/perovskite and HTL/perovskite interfaces, which play a decisive role in the solar cell performance. Therefore, this study aims to enhance the flexible PSC (FPSC) efficiency by adding the newly designed CBz-PAI-interlayer (simply CBz-PAI-IL) at the perovskite/HTL interface. In addition, substantial work has been carried out on five different HTLs (Se/Te-Cu2O, CuGaO2, V2O5, and CuSCN, including conventional Spiro-OMeTAD as a reference HTL with and without CBz-PAI-IL), using drift-diffusion simulation to find suitable FPSC design to attain the maximum PCE. Interestingly, PET/ITO/AZO/ZnO NWs/FACsPbBrI3/CBz-PAI/Se/Te-Cu2O/Au device architecture demonstrates the highest achievable power conversion efficiency (PCE) of 27.9%. The findings of this study confirmed that the reference device (without IL) displays a large valence band edge (VBE)/highest occupied molecular orbital (HOMO) energy level misalignment compared to the modified interface device (with CBz-PAI-IL that reduces VBE/HOMO level mismatch) that eases the hole transport, simultaneously, it reduces the charge carrier recombinations at the interface, resulting in diminished Voc losses in the device. Furthermore, the influence of perovskite absorber thickness and defect density, parasitic resistances, and working temperature are systematically examined to govern the superior FPSC efficiency and concurrently understand the device physics.

Flash soldering of boron nitride nanosheets for all-ceramic films

The assembly of boron nitride nanosheets (BNNSs) into strong, flexible thin films capable of withstanding extreme conditions, such as high/low working temperatures and corrosive environments, holds immense promise for numerous applications. However, BNNSs are difficult to assemble and sinter to achieve the dense thin film structure observed in graphene thin films. We report the rapid fabrication of dense BNNS all-ceramic films (BACFs) in 30 s by combining the fabrication strategies for 2D and ceramic materials. In this process, densely arranged and highly oriented BNNSs are flash soldered into a monolith achieved by precisely controlled ultrafast sintering. This fusion of BNNS leads to an ultrahigh in-plane thermal conductivity of 134.5 W·m−1·K−1, which was among the highest values for BNNS films (mostly ≤ 70 W·m−1·K−1). The as-prepared BACF exhibits the combined advantages of sintered ceramics (durability, stability, acid-alkali resistance) and 2D material films such as flexibility and shock resistance, which is important for practical uses but rarely found in existing ceramics. It also has excellent cooling performance, dielectric properties, and good thermal stability, which is promising for demanding thermal management applications in emerging technologies.

Physicochemical and electrochemical properties of several readily available anthraquinone aqueous electrolytes

Aqueous organic redox flow batteries (AORFBs) have become a research hotspot due to their resource sustainability and high security. In which, water-soluble anthraquinone derivatives are the most widely used anodic active electrolytes, and their molecular structure, concentration and work temperature have a direct influence on their physicochemical properties and electrochemical performance, while data on such studies are scarce. In this paper, three typical and low-cost anthraquinone derivatives, including sodium anthraquinone-2-sulfonate (AQS) containing −SO3−, 1,4-dihydroxy-9,10-anthraquinone (DHAQ) containing –OH and sodium 3,4-dihydroxy-9,10-anthraquinone-2-sulfonic acid (ARS) containing both −SO3− and –OH are systemically studied. The effects of temperature, concentration of active electrolyte and supporting electrolyte on the viscosity, conductivity, surface tension and electrochemical properties of these most promising anthraquinone-based electrolytes are investigated systematically. The results show that the three anthraquinone derivatives show obvious differences in physicochemical properties and electrochemical reaction kinetics, and their sensitivity to temperature and concentration is also different, which provides useful information for the design of anthraquinone-based AORFBs.

High performance Cu sintering joint for power devices enabled by in-situ generation of Cu particles with multi-level hierarchical structures

Copper (Cu) particle sintering is widely regarded as one of the most ideal interconnect technologies for wide band gap semiconductors owing to its potential for low-temperature curing while withstanding a higher working temperature. Nevertheless, the strict requirements for sintering conditions and high costs limit the widespread application of Cu sintering technology. In this paper, a simple vehicle was introduced into Cu paste formulation to achieve an effective sinter bonding even using commercially available sub-micron or even micrometer Cu particles (C-Cu particles) with the in-situ generation of composite Cu particles. This innovative vehicle comprises Cu salt, a combination of capping agents and reducing agents. The addition of the hybrid capping agent binds Cu atoms to the surface of the C-Cu particles and allows the generated Cu particles (G-Cu particles) produced from the vehicle to grow on their surface, resulting in the in-situ generation of composite Cu particles. Based on the in-situ generated composite Cu particles, sintering experiments were conducted at designated temperatures (200 °C, 225 °C, 250 °C) for various durations (3min, 5min, 10min) in a N2 atmosphere under different pressures (10MPa, 15MPa, 20MPa). A reliable Cu sintered joint with a high shear strength of 41.3MPa can be achieved at a low temperature (200 °C) using 500 nm C-Cu particles. Moreover, the joints sintered with large size (>3 μm) particles at 250 °C could also reach 43.3MPa. The in-situ generated composite Cu particles accomplish the transformation of low-energy interfaces of C-Cu/C-Cu to high-energy interfaces of G-Cu/G-Cu, which in turn facilitates low-temperature sintered connection of C-Cu particles and reliable sintered joints formed of large size C-Cu particles. These findings improve the feasibility of Cu sinter bonding in practical applications.

Deprotection of the BOC Groups in Poly(2-(tert-butoxycarbonyloxy)ethyl methacrylate) Controlled by the Incorporation of Polymerizable Thermally Latent Acids

Poly((2-tert-butoxycarbonyloxy)ethyl methacrylate) (PBHEMA) is converted to poly(2-hydroxyethyl methacrylate) (PHEMA) with the release of isobutene and CO2 by heating and this reaction is accelerated by an acid. The thermal latent acid catalysts (TLA) are useful for the control of a working temperature for the deprotection of the tert-butoxycarbonyl (BOC) groups included in PBHEMA. In this study, styrene- and methacrylate-type sulfonic esters were synthesized and copolymerized with BHEMA in order to investigate the effect of the TLAs incorporated into the polymer chains. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out for the copolymers of BHEMA with the polymerizable TLAs in order to discuss the deprotection features of the BOC group in comparison with the results for the systems of PBHEMA blended with the low-molecular-weight TLAs.

Ppb-level unsymmetrical dimethylhydrazine detection based on In2O3 hollow microspheres with Nd doping

As one of main high-energy fuels for rocket launching, unsymmetrical dimethylhydrazine (UDMH) and its decomposition products do harm to environment and human health. It is significant to develop a device to monitor its leakage. In this work, a UDMH gas sensor based on In2O3 hollow microspheres with Nd dopant was fabricated. The pure, 1.0mol%, 3.0mol% and 5.0mol% Nd doped In2O3 were synthesized via one-step solvothermal method. Among them, 3.0% Nd-In2O3 based sensor exhibits the highest response toward UDMH vapor. Its response value to 100 ppm UDMH is 183.3 at optimal working temperature of 250°C, 6.8 times higher than that of pure In2O3 (26.8). Besides high response to UDMH, the 3% Nd-In2O3 based sensor represents excellent selectivity, rapid response speed (2s) and ultra-low theoretical LOD to UDMH (0.28 ppb). The improved gas sensing performance via Nd doping could be attributed to the enhanced specific surface area, increased concentration of adsorbed oxygen and improved adsorption capacity for UDMH molecular on the surface. The excellent sensing performance of Nd doped In2O3 hollow microspheres makes it a promising candidate for real-time UDMH detection. Environmental ImplicationUnsymmetrical dimethylhydrazine (1,1-dimethylhydrazine, UDMH) is a colorless, highly toxic compound. It has been classified as 2B human carcinogen by the International Agency for Research on Cancer (IARC). The National Institute for Occupational Safety and Health (SLOSH) also regulates the UDMH concentration limitation of 0.06 ppm in workplace. Therefore, it is urgent to fabricate a device for detecting the UDMH leakage timely during its storage and transport. In our work, Nd doped In2O3 hollow microspheres based chemiresistive gas sensor for the monitoring of UDMH was developed, which will promote the practical applications for gas sensor.

Design of Laser-Powered Opto-Electrical Current Transformer and Its Application in Electrical Automation of Substations

The novel power equipment represented by the Opto-Electrical Current Transformer (OECT) possesses unparalleled advantages compared to traditional Current Transformers (CTs), rendering it with vast potential in power systems. In the design of OECT, this study employs laser power supply and focuses on the overall perspective, particularly the design of the laser power supply module and the optical fiber digital transmission module. The laser power supply module selects a high-power semiconductor laser to provide power to the circuit, incorporating line filters, thermistor resistors, and a laser overcurrent protection circuit. An automatic temperature control circuit based on PI regulation is utilized to stabilize the working temperature of the laser diode (LD). The photoelectric conversion device PPC-6E achieves a maximum photoelectric conversion efficiency of 40%, and the MAX639 DC–DC conversion chip ensures stable output voltage. The optical fiber digital transmission module adopts a circuit composed of multiple NOR gate logic for electro-optical conversion, a low-power driving circuit based on the 74LVC1G07 chip, and the HFBR-2412 photoelectric converter to simplify the circuit board design. To achieve a higher communication baud rate, a quartz multimode optical fiber with a diameter of 62.5 μm is chosen. In the experimental phase, a simulation of high-power AC power with equal turns is conducted. The linearity/temperature test results demonstrate that the designed OECT in this study meets expectations. In the electrical automation test of substations, a comparison between traditional CTs and the designed OECT is carried out using traditional protection algorithms and optical differential protection algorithms. The results indicate that, compared to traditional protection algorithms, the optical differential algorithm using the designed OECT achieves faster protection times.

Estimation of SOC in Lithium-Iron-Phosphate Batteries Using an Adaptive Sliding Mode Observer with Simplified Hysteresis Model during Electric Vehicle Duty Cycles

This paper develops a model for lithium-ion batteries under dynamic stress testing (DST) and federal urban driving schedule (FUDS) conditions that incorporates associated hysteresis characteristics of 18650-format lithium iron-phosphate batteries. Additionally, it introduces the adaptive sliding mode observer algorithm (ASMO) to achieve robust and swiftly accurate estimation of the state of charge (SOC) of lithium-iron-phosphate batteries during electric vehicle duty cycles. The established simplified hysteresis model in this paper significantly enhances the fitting accuracy during charging and discharging processes, compensating for voltage deviations induced by hysteresis characteristics. The SOC estimation, even in the face of model parameter changes under complex working conditions during electric vehicle duty cycles, maintains high robustness by capitalizing on the easy convergence and parameter insensitivity of ASMO. Lastly, experiments conducted under different temperatures and FUDS and DST conditions validate that the SOC estimation of lithium-iron-phosphate batteries, based on the adaptive sliding-mode observer and the simplified hysteresis model, exhibits enhanced robustness and faster convergence under complex working conditions and temperature variations during electric vehicle duty cycles.