Normal Operating Conditions Research Articles

Evaluation of operational reliability of diesel fuel system elements

In the article, as a result of a review and analysis of studies on the reliability of elements of the power system of diesel engines, it was determined that the cause of most failures of elements of the power system is the presence of impurities and water in the fuel, and the use of a defective fuel filter. The purpose of the study is to assess the degree of reliability of elements of the power supply system of diesel engines under normal operating conditions. For this purpose, an observation program has been drawn up for a group of intensively working tractors. Taking into account apriori information, the following elements (nodes) were selected as observed elements. P1—fuel tank and fuel lines, P2—settler filter, Pz— high pressure fuel pump; P4 – fuel nozzle. The observation results were subjected to statistical processing and the probabilities of failure-free operation of each element were constructed. The correlation dependence of failure-free operation between the observed elements of the power system was assessed. To assess the actual reliability, the main statistical characteristics of the time between failures of the elements of the power system of the diesel engines of the tractors participating in the experiment were calculated. Graphs of the distribution of time between failures of power system elements were constructed, conclusions were drawn regarding the reliability and service life of the elements.

UVC-Mirror for effective pathogens inactivation in air ducts

Improving the air quality of indoor environments (IAQ) is of utmost importance to safeguard public health as people spend about 80–90% of their time indoor. Efficient Ultraviolet germicidal irradiation (UVGI) system represents a strategic and sustainable solution to protect from recurrent and new airborne pathogens. Here, we present a new approach to design highly efficient UVGI systems, which can be installed in existing Air Treatment Units (ATU) plants with minimal effort. The increased efficiency relies on the concept of an optical cavity, thanks to its shape and source position. The internal volume consists of a highly reflective cavity illuminated with UV-C lamps. Optical simulations permitted the variation of the parameters to maximize the internal irradiance and, thus, the performance. The sanitation efficacy of the system was assessed on a full-scale pilot system. Tests were carried out under normal operating conditions against various microorganisms showed an inactivation rate of > 99%. The benefits of such systems are triple and encompass economic, environmental, and societal aspects. Since the system requires little energy to operate, its application for air disinfection may yield significant energy savings and ensure a balance between energy sustainability and good IAQ.

Радиологическая безопасность населения и персонала при двухкомпонентной ядерной энергетике

The Fundamentals of State Policy in the Field of Nuclear and Radiation Safety of the Russian Federation, approved by the President of the Russian Federation, indicate that the goal of state policy in this area is to ensure the protection of the population, considering modern requirements. The IAEA Fundamental Safety Principles emphasize the need to protect both current and future generations from radiation risks. The achievement of these safety goals is ensured by the development in Russia of new nuclear energy system based on a closed nuclear fuel cycle (CNFC) and fast neutron reactors (FNR). One of the objects of the new nuclear energy system is the Experimental Demonstration Energy Complex (EDEC) consisting of the BREST-OD-300 FNR, a reprocessing module and a fuel fabrication/refabrication module, located on the territory of JSC «SHK» in the Tomsk region. This article provides assessments of radiation carcinogenic risks for the population living in the 30-km zone of JSC «SHK» under normal operating conditions and for workers after potential emergency situations at EDEC facilities. The conditions for ensuring the protection of future generations of people are also justified. Radiation risk assessments are obtained directly from the dynamics of equivalent doses in human organs and tissues and modern risk models recommended by ICRP Publication 103. The predicted values of the risks of radiation carcinogenesis for the population and personnel are significantly lower than the current limits of NRB-99/2009 for both normal operation and potential exposure during accidents. It has been shown that transmutation of minor actinides during the development of CNFC based on FNR ensures the safety of future generations of people: it reduces the carcinogenic risk of americium by 213 times, neptunium by 101 times, and curium by 47 times. The effect of radiological equivalence of radioactive waste and natural uranium raw materials is achieved after 99 years of radioactive waste storage. Thus, the priority direction for the development of new nuclear power is the energy sector of the CNFC based on the FNR.

Flexible solid-solid phase change material with zero leakage via in-situ preparation for battery thermal management

<p>Composite phase change material (CPCM) has great potential in addressing the challenges associated with thermal energy storage and thermal management. However, the flexibility and latent heat capacity of CPCM exist contradiction, hindering its wide application, especially in thermal management field. Herein, a novel solid-solid polyurethane structured phase change material including as chain segments PEG4000 and hexamethylene diisocyanate coupling with expanded graphite (PHE5) has been proposed and prepared via in-situ approach. Expand graphite is uniformly distributed and the carbamate group is produced by in-situ preparation, the high latent heat and anti-leakage characteristics of PHE5 are beneficial to sustain a constant mass with zero leakage even under 150�� heating condition. At a 3 C discharge rate, the battery module with PHE5 can reduce the maximum temperature to 59��, which is lower than the PE-based module. Additionally, the battery system can maintain the temperature difference below 4.5��, ensuring uniform temperature within the battery module. The flexibility and controlling temperature capabilities of PHE5 can effectively dissipate heat during charge and discharge cycles, and the mechanistic analysis of PHE5 with anti-leakage property can enhance the battery thermal safety, achieving comprehensive protection throughout normal operating and extreme conditions. Thus, this research reveals that solid-solid CPCM with polyurethane structured can improve the flexible and anti-leakage properties via in-situ preparation, which will offer an effective thermal safety solution for battery module, substantially enhancing the safety of millions of drivers and passengers.</p>

Ensuring sustainability of the power supply system of mining enterprises in the conditions of war risks

In the work, a study of the conditions of normal operation of the power supply system of mining enterprises with limited capacity of the power system was carried out. Based on complex studies, conclusions were drawn about the structure of electrical loads in coal mines, which are characterized by a non-linear and non-symmetric nature. The problem of higher harmonics and interharmonics with limited short-circuit power, which is characteristic of an autonomous power supply system, is highlighted. Stable operation of the power supply system and main consumers is achieved by matching the mode of the generator set with the mode parameters of the load. New dependencies of regime parameters were obtained, which evaluate energy efficiency in complex situations caused by military risks. Experimental studies of voltage quality indicators and energy efficiency in the conditions of power supply systems of coal mines of Ukraine confirmed the adequacy of the proposed analytical models.

One-Class Classification-Based Monitoring of Mineral Processing Operations with Hyperensemble Tree-Models

Reliable monitoring of mineral process systems is key to more efficient plant operation. Multivariate statistical process control based on principal component analysis is well-established in industry, but may not be effective when dealing with nonlinear or transient processes, where process behaviour can change rapidly over time. Although many advances have been made in unsupervised process monitoring, the detection of incipient process drift or nascent abnormal process conditions remains an open research problem.In this investigation, monitoring of mineral process operations based on the use of random forest classifiers is considered. When the random forests are used, data representing normal operating conditions are split into subclasses with K-means clustering, after which an ensemble of random forests is trained as binary classifiers on the subclasses in a one-against-the-rest approach. These hyperensemble models are subsequently used to classify new operational data as in-control or out-of-control.One simulated and one real world case study are considered. In each case, the models were trained on data representing normal operating conditions and then tested on new process data that were generally different from the training data to test their ability to identify these data as out-of-control. In the real-world case study, the approach is compared with traditional multivariate statistical process monitoring based on a principal component model, as well as a recently proposed isolation forest model. The random forest-based models performed markedly better than the principal component model and slightly better than the isolation forest model as far as identification of out-of-control data were concerned, but this came at the expensive of a significantly larger false positive rate than these two models.

Design and calculation of cold storage capacity of 10 tons for tuna commodity

The Ministry of Maritime Affairs and Fisheries, Republic of Indonesia, urges economic stakeholders to maximize increasingly open export opportunities. With an abundance of fishery products in Indonesian waters, it must be supported by adequate facilities, one of which is the availability of cold storage, which maintains the quality of fishery products. In this study, the design of the cold storage was carried out by measuring the size of the cold storage and using the calculation of the cooling load, the calculation of cooling capacity, the calculation of the P-h diagram, and the cost estimate. The results of this study include cold storage design dimensions of 420 m3 with a long length and tall of 15×7×4 m3 made from insulation materials of polyurethane, stainless steel, and plaster. The cooling load data for the cold storage, when the product (tuna) is cooled and filled, is 3,707,444.3 kJ every 24 hours. A ton of refrigeration absorbs 12,660 kJ per 24 hours, equaling 16.3 tons of required refrigeration capacity. Meanwhile, under normal operating conditions, the total cooling load is 759,427.588 kJ per 24 hours. After calculating the cooling load, it was discovered that the initial design, which only had a capacity of 10 tons during the refrigeration process, could accommodate a cooling capacity of up to 16.3 tons. The cooling capacity of cold storage is 23.9 kW or 81.400 Btu/h. P-h diagram calculation of compressor cooling load is 0.7 kW, and the cooling load total from the evaporator to keep air room temperature of cold storage 0 °C is 0.43 kW. Estimated cost total for materials of cold storage design is USD 128,655. Highlights Refrigerator facilities are still limited in reaching remote coastal areas The cooling system must start using renewable energy Cold storage is used to maintain the quality of fishery product so that they remains in good condition From the calculation results, knowing the total cooling load when the cold storage is working, knowing the total cooling capacity of the cold storage when it is used as a fish storage refrigerator, and knowing the total estimated operational costs of the cold storage

Looking beyond individual failures: A system-wide assessment of water infrastructure resilience to extreme events

Water infrastructure systems throughout the United States face compounding challenges due to aging infrastructure and increasingly extreme and more frequent weather events. Identifying vulnerabilities and assessing systems’ ability to withstand and recover from such events is a critical component of water infrastructure planning and management. Pipe failures and system structure can substantially impact water infrastructure resilience, but these two factors are often assessed separately. Here, we present a holistic assessment of system performance that considers pipe failures, active water storage, and system structure utilizing data collected during normal and emergency operating conditions. The four-step framework evaluates pipe failures spatially and temporally to assess overall system performance, as measured by active storage, and identifies targeted areas for improvements. Employing control charts, resilience curves, and spatial clustering analysis, our results simultaneously reveal an agreement between trends in pipe failures during normal and emergency operating conditions as well as unexpected discrepancies between pipe failures and system performance due to the water system structure. Our results offer insights to utilities seeking to assess system vulnerabilities to increase water infrastructure resilience to extreme events.

Strong acid-mediated Ca2+ extraction–CO2 mineralization process for CO2 absorption and nano-sized CaCO3 production from cement kiln dust: Simultaneous treatment of CO2 and alkaline wastewater

Increasing yearly stockpiles of cement kiln dust (CKD) and the associated high landfilling cost require innovative solutions to utilize CKD. This study proposes a strong acid-mediated extraction–mineralization process that utilizes CO2. The process comprises the extraction of Ca2+ from CKD using strong acids, mineralization of CO2 using extracted Ca2+ and alkaline wastewater, and production of Ca carbonate. High Ca2+ leaching efficiency, high Ca2+ extraction efficiency, and high-purity nano-sized CaCO3 production from CKD were achieved under normal operating conditions in an in-situ strong acid solution. The process feasibility was primarily tested via an individual extraction process using aqueous HCl and HNO3 solutions from typical CKD and mineral carbonation experiments using Ca(OH)2 and alkaline wastewater obtained from the extraction process. The process had a Ca2+ leaching efficiency of 94.73%, Ca2+ extraction efficiency of 93.54%, and CaCO3 yield of 1.45 ton/ton CKD in the aqueous HCl solution. Polymorphism and crystal structure analyses showed that CaCO3 obtained after CO2 mineralization was mainly present as calcite. Alkaline wastewater acted as a pH buffer, enhanced the reactivity with CO2, accelerated the conversion of CO2(g) to CO32-(aq), and acted as an accelerator that promoted the nucleation growth of CaCO3 by OH- ions during the mineralization process. The effect of the nucleation and growth of CaCO3 on the particle and crystallite size is highly dependent on the system pH. These results can be applied to CO2 utilization processes by industrial by-products.

Li-Ion Cell in Operando Monitoring and Prognostication Using CMUT Devices

Capacitive micromachined ultrasonic transducer (CMUT) devices are ideal solutions for in operando battery monitoring applications especially for consumer electronics. Their minute size (2mm x 1mm x 0.5mm) allows direct placement on the battery without affecting the form factor of the device, the volume production techniques used for their manufacture allow for a very low-cost device, and they can be easily integrated with front-end integrated circuits either in a single device or in a discrete multichip form. Together with industry partners we have developed CMUT devices that we use to continuously monitor the behavior of a battery while it is cycling.For this work we used CMUTs (close-up shown in Fig. 1(a)) developed to operate with a low bias voltage (less than 30 V) which reduces the complexity of the driving hardware. The impulse response and its frequency content are shown in Fig. 1(b). In collapse mode, the peak frequency is 4.0 MHz and the one-way –3 dB BW is 76%, which allows flexibility in setting the drive conditions to interrogate the battery. Our testing also shows that the CMUTs show good device-to-device uniformity and they have a very stable performance in variable temperature environments (e.g. 0℃ - 60℃ ).The cell is interrogated in pulse-echo mode. The CMUT is excited by a wide-band unipolar pulse and the returned analog signal is filtered and amplified. The signal is then digitized and processed to extract features that allow us to quantify the state of the battery. Figure 1(c) depicts such signal features change under baseline cell cycling conditions (three cycles at a charge rate of C/4). These changes are the result of mechanical material property changes in the cell e.g., electrode stiffness and density [1] which directly affect the acoustic wave propagation inside the cell. Figure 1(d) depicts signal feature change due cell overcharge (red line). Ultrasound is especially sensitive to gas generation which occurs as the cell voltage extends beyond normal operating range [2]. Signal features provide early warning notice that cell is outside of normal operating conditions.Figure 1. a) Close-up image of CMUT device. b) CMUT impulse response and corresponding frequency content. c) Signal features (RMS and Time of Flight (ToF)) and thickness change during C/4 charge and discharge. d) Signal features during cell constant current overcharge. Cell overcharged after 4.4V (red line). Chang, W. et al. Measuring effective stiffness of Li-ion batteries via acoustic signal processing. Mater. Chem. A 8, 16624–16635 (2020).Appleberry, M. C. et al. Avoiding thermal runaway in lithium-ion batteries using ultrasound detection of early failure mechanisms. Journal of Power Sources 535, 231423 (2022). Figure 1

On the issue of carrying out mooring tests of a ship power plant in shallow water conditions

In the process of mooring trials, as well as when ships are sailing in shallow water, difficulties often arise in ensuring normal operating conditions for the propulsion complex, the performance of the power plant and the ship as a whole. The article outlines the problems during mooring tests in shallow water. Mooring tests of a large-tonnage tanker in shallow water conditions are considered, when the operation of the main circulation pump of the cooling system is disrupted due to contamination of the flow path of the main condenser with soil particles. The economic inexpediency of testing a tanker at sea when it is anchored or barreled in an area that is safe for navigation and has sufficient water depth is substantiated. The method of taking cooling water from above with the help of a caisson is considered, which eliminated unproductive costs. A method of mooring a ship is given, in which the water jet from the propeller does not harm the berthing facilities and does not erode the soil of the water area; the means of simulating the nominal parameters of the actuators are described, which makes it possible to carry out mooring tests of mechanisms, systems and devices without bringing the main power plant to the mode of increased loads, and, as a result, to reduce the testing time.

A New Index to Detect Process Deviations Using IR Spectroscopy and Chemometrics Process Tools

Process analytical technologies (PATs) have transformed the beverage production management by providing real-time monitoring and control of critical process parameters through non-destructive measurements, such as those obtained with infrared (IR) spectroscopy and enabling process readjustment if necessary. New requirements in the analysis of beverages call for new methods, so in this article, we propose a method based on the construction of multivariate statistical process control (MSPC) charts from a new dissimilarity index (the evolving window dissimilarity index, EWDI) to monitor fermentation processes. The EWDI was applied to monitor wine alcoholic fermentation, the biochemical transformation of sugars into ethanol. Small-scale fermentations were carried out and analyzed using a portable mid-infrared spectrometer. In some of them, process deviations due to nitrogen deficiency or temperature changes were intentionally promoted to evaluate the performance of the EWDI. The MSPC charts build by using the fermentations carried out under normal operating conditions allowed identifying deviations of the fermentation in its early stages. Furthermore, the shape of the EWDI curve over time provides insights about the specific type of deviation occurring. These results show the potential of this new approach to improve the monitoring and control of key process stages in biochemical processes in the food industry, which allows maximizing quality and minimizing losses.Graphical

Visualization of thermo-fluid behavior of loop heat pipe with two evaporators and one condenser under various orientations with uneven heat loads

This research conducted experimental investigations into the operating characteristics of a Multi-evaporator loop heat pipe (MLHP) with two evaporators and one condenser under uneven heat load conditions. Notably, it pioneered the visualization of the detailed internal flow phenomena in the evaporator cores, and compensation chambers (CCs). Two categories of experiments were conducted. The first category focused on heat load sharing conditions by heating a single evaporator in three different attitudes: gravity-assisted (with the condenser positioned above the evaporators), horizontal (with the condenser positioned at the same height as the evaporators), and anti-gravity (with the condenser positioned below the evaporators). These tests were the pioneering effort to investigate the effects of gravitational head on the heat load sharing phenomena. The second category of experiments simulated normal operating conditions, involving heating both evaporators with different heat loads in the horizontal attitude. These tests were the pioneering attempt to examine the hysteresis effect on internal flow phenomena in each evaporator core and CC under various heat load conditions. To further investigate the hysteresis effect in MLHP, a comparison of the internal flow phenomena in the evaporator and CC was made at the identical heat loads in different heat loads cycle tests. The findings indicated that internal flow phenomena in each evaporator core and CC depended not only on the current heat loads but also on the previous heat load conditions. Temperature measurements were conducted to establish the relationship between visualization results and temperature variations. The visualization results and the corresponding temperature data were used to summarize pressure and temperature profiles for each component of the MLHP. This included the two novel pressure and temperature profiles unveiled in the normal operating tests with different heat loads and the two novel pressure and temperature profiles unveiled in the heat load sharing tests.

Calibration, validation, and selection of hydrostatic testing-based remaining useful life prediction models for polyethylene pipes

A novel methodology for model selection among competing models for remaining useful life (RUL) prediction is developed in this paper. Due to the long durability of polyethylene (PE) pipes under normal conditions, life data under normal operating conditions is not available for model validation and selection. Physics-based, regression-based, and hybrid models for RUL prediction are available in the literature based on experimental data under accelerated test conditions. These models need to be evaluated for prediction performance under normal conditions, but in the absence of data under normal conditions. A model consistency-based metric for selecting the best model in the absence of data under normal conditions is proposed in this paper. The consistency-based metric evaluates the predictive consistency of the various probabilistic RUL prediction models over the estimated or known probability distribution of the normal operating conditions. A two-step approach for model selection is proposed: first, validation evaluation using empirical data, and second, consistency evaluation under likely operating conditions. The proposed model selection methodology is demonstrated using five candidate models for RUL prediction of PE pipes based on accelerated hydrostatic testing data. Bayesian inference is used to calibrate these models with empirical data, and its benefit over the least squares approach recommended in ISO 9080 is demonstrated. Further, the proposed two-step model selection methodology is compared against traditional model selection methods based on goodness of fit, model complexity and information theoretic metrics. It is seen that the proposed additional consistency criterion is successful in selecting the best model compared to existing methods that are unable to distinguish between the different available models.

Anomaly Detection of Axial Piston Pump Based on the DTW-RCK-IF Composite Method Using Pressure Signals

Axial piston pumps are critical components of hydraulic systems due to their compact design and high volumetric efficiency, making them widely used. However, they are prone to failure in harsh environments characterized by high pressure and heavy loads over extended periods. Therefore, detecting abnormal behavior in axial piston pumps is of significant importance. Traditional detection methods often rely on vibration signals from the pump casings; however, these signals are susceptible to external environmental interference. In contrast, pressure signals exhibit greater stability. In this study, we propose a novel anomaly detection method for axial piston pumps, referred to as DTW-RCK-IF, which combines dynamic time warping (DTW) for data segmentation, a random convolutional kernel (RCK) for feature extraction, and isolation forest (IF) for anomaly detection using pressure signals. The model is trained using normal operating data to enable the effective detection of abnormal states. First, the DTW algorithm is employed to segment the raw data, ensuring a high degree of similarity between the segmented data. Next, the random convolutional kernel approach is used in a convolutional neural network for feature extraction, resulting in features that are representative of normal operating conditions. Finally, the isolation forest algorithm calculates the anomaly scores for anomaly detection. Experimental simulations on axial piston pumps demonstrate that, compared with vibration signals, the DTW-RCK-IF approach using pressure signals yields superior results in detecting abnormal data, with an average F1 score of 98.79% and a good fault warning effect. Validation using the publicly available CWRU-bearing and XJTU-SY-bearing full-life datasets further confirms the effectiveness of this method, with average F1 scores of 99.35% and 99.73%, respectively, highlighting its broad applicability and potential for widespread use.

Modeling hydrogen localization in Zircaloy cladding subjected to temperature gradients

In light water reactors, Zr-based alloys used for nuclear fuel cladding undergo oxidation and absorb hydrogen, which can precipitate as brittle zirconium hydrides. During reactor normal operation conditions, hydrogen concentration varies locally due to various factors, where local high concentration can significantly degrade cladding mechanical properties and, hence, its service life. This study aims to quantify the redistribution of hydrogen within the fuel rods caused by temperature gradients, considering geometric irregularities such as inter-pellet regions, oxide spallation, and missing pellet surfaces. Through simulations, we have discovered that these temperature variations can lead to significant local hydrogen enrichment, even under normal operational conditions. Consequently, the Zircaloy cladding may suffer from critical weakening in its mechanical performance due to excessive hydride precipitation at specific locations. These findings underscore the importance of accounting for local hydrogen concentrations when evaluating the overall reliability of the cladding.

The influence of plating with flat bars around technological cutouts on the stress state of a 37500 tdw chemical tanker

The purpose of this study is to determine the stress states of the plating around the technological cutouts of a 37500 tdw chemical tanker under normal operational conditions, taking into account the efficiency of operational optimization and structural strength increase. This study will assess the stress state in the double bottom region of the ship, which experiences the most significant external loads from hydrostatic water pressure and internal loads from cargo pressure.

Load study and structural analysis for CFETR divertor OVT

China Fusion Engineering Test Reactor (CFETR) is an important device for studying fusion reactor engineering in China. The Outer Vertical Target (OVT) are high heat load components of the divertors and work in a strong electromagnetic field, so they need sufficient heat removal capability and structural strength. In addition, due to activation of neutrons on materials, the OVT also needs to meet the requirements of Remote Handling (RH) maintenance. CFETR puts forward the concept of hybrid divertor-blanket, which cancels the cassette and adopts a separate structure. The lower part of the divertor is occupied by the breeding blanket, and the divertor target is fixed on the breeding blanket, to improve the RH maintenance efficiency and Tritium Breeding Ratio (TBR). In previous work, the structural design and thermal-hydraulic analysis of the OVT were completed. In this paper, load study and structural analysis was carried out to verify the structural strength of the OVT under experimental test conditions (including liquid pressure, nitrogen baking), normal operation conditions (including the impact of thermal stress under thermal load, gravity, working pressure, etc.) and extreme event conditions (Vertical Displacement Event (VDE) or Major Disruption (MD) event, including the impact of thermal stress under thermal load, gravity, working pressure, electromagnetic load, etc.). The results show that the OVT meets the requirements of heat removal and strength, and effectively promote the processing and manufacturing of the prototype of the OVT.

Study on physical explosion equivalent of large diameter and high pressure natural gas pipeline

High pressure natural gas pipelines are prone to material failure and explosion due to various reasons. Over the years, scholars have done in-depth research on the process of chemical explosion. In this paper, the energy components of high-pressure trunk natural gas pipeline under normal operation state were derived. Based on the assumption of adiabatic non isentropic, the pressure distribution in the pipeline within a period of time after the pipeline cracks was derived, and the energy released by the physical explosion of the pipeline was further derived. To verify the theoretical results, an original size pipe explosion experiment was organized, and the pressure distribution obtained from the experiment was found to be in good agreement with the theoretical calculation results. Through the crack propagation time and the duration of ground motion obtained from the experiment, the range of the duration of the pipeline burst crack impact was obtained, and the equivalent range of the pipeline explosion was further calculated. At the same time, through the regression analysis of ground motion, the equivalent of the pipe explosion in this experiment was about 177 kg TNT, which was consistent with the theoretical results. Further, the theoretical model and experimental results were verified by numerical simulation, and deeply studied the influence factors of buried depth on the explosion equivalent, as well as the relationship between the environment of the pipeline and the explosion damage mode and hazard range of the pipeline. The research results of this paper give the calculation method and magnitude range of physical explosion equivalent of high-pressure trunk natural gas pipeline. It provides a reference for the formulation of safety standards for high-pressure trunk natural gas pipelines and inert gas pressure vessels.

Numerical and experimental investigation of the electrical and thermal behaviors of the Li-ion batteries under normal and abuse operating conditions

This paper presents the results of a comprehensive investigation of the electrical and thermal behaviors of the Lithium (Li)-ion batteries under normal and abuse conditions. In the first part of the study, an electrochemical-thermal coupled model is developed to predict the thermal and electrical characteristics of a Li-ion battery at 20 and 50 °C temperatures for varying discharge rates based on a detailed sensitivity analysis of the electrochemical and thermal model parameters. The experimental and model data are consistent, considering the discharging processes at 0.5, 1, and 1.5C rates under 20 and 50 °C operating temperatures. In the second part of the study, thermal abuse experiments are conducted by heating the Li-ion cell using the film heater at various charge states of battery. Simulations are carried out for the heating tests by enhancing the electrochemical-thermal model using the temperature-dependent Arrhenius equations. The results show that the thermal abuse model can predict the thermal runaway initiation time within the approximate 10 % margin of error, and the maximum surface temperature with 10.5 % of error compared to the experimental results of the completely charged Li-ion cell.