Thermal Failure Research Articles

Performance of photovoltaic panels with different inclinations under uniform thermal loading

Integrating photovoltaic (PV) panels with different tilt angles in building envelopes or roofs is widely employed for environmental sustainability. However, little is known about the influence of different tilt angles on the thermal failure of the photovoltaic façades or roofs in fire conditions. A total of 15 four-edge shielded PV panels (300 × 300 × 4.7 mm3), with five different inclinations of 0°, 15°, 30°, 45° and 60°, were heated to fail using a uniform radiant panel. Measurements were taken to track glass thermal breakage, surface temperatures, incident heat flux and failure characteristics. The glass fracture and pyrolysis of the internal thermoplastic materials were observed under thermal radiation. The average breakage time of glass in PV panels showed an increasing trend with increasing inclination of the PV panels. Moreover, when the PV panels were tilted beyond 30°, the time to failure increased more significantly. The maximum temperature difference and heat flux that the PV panels can withstand were primarily measured within the range of 61–84 °C and 8–15 kW/m2, respectively. Finally, the test results were simulated by a finite element method (FEM) model, calculating the heat transfer and thermal stress of PV panels: the average errors concerning temperature distributions and failure times were smaller than 15 % compared with the experimental results.

Multi-Step Temperature Prognosis of Lithium-Ion Batteries for Real Electric Vehicles Based on a Novel Bidirectional Mamba Network and Sequence Adaptive Correlation

The battery systems of electric vehicles (EVs) are directly impacted by battery temperature in terms of thermal runaway and failure. However, uncertainty about thermal runaway, dynamic conditions, and a dearth of high-quality data sets make modeling and predicting nonlinear multiscale electrochemical systems challenging. In this work, a novel Mamba network architecture called BMPTtery (Bidirectional Mamba Predictive Battery Temperature Representation) is proposed to overcome these challenges. First, a two-step hybrid model of trajectory piecewise–polynomial regression and exponentially weighted moving average is created and used to an operational dataset of EVs in order to handle the problem of noisy and incomplete time-series data. Each time series is then individually labeled to learn the representation and adaptive correlation of the multivariate series to capture battery performance variations in complex dynamic operating environments. Next, a prediction method with multiple steps based on the bidirectional Mamba is suggested. When combined with a failure diagnosis approach, this scheme can accurately detect heat failures due to excessive temperature, rapid temperature rise, and significant temperature differences. The experimental results demonstrate that the technique can accurately detect battery failures on a dataset of real operational EVs and predict the battery temperature one minute ahead of time with an MRE of 0.273%.

A study on the temperature rise characteristics of high-speed ball bearings under starvation lubrication

Purpose This paper aims to study the problem of starvation lubrication of high-speed ball bearings due to temperature rise during operation and to avoid thermal failure of bearing lubrication. Design/methodology/approach Under the quasi-statics model of grease lubrication, both the oil film dragging force and the rolling friction between the balls and raceways collectively counteract the gyroscopic torque. Initially, the static model for grease lubrication is solved, followed by calculating the generated heat using the local heat generation method and ultimately the multinodal thermal network model is solved, and the solved results of the quasi-statics are updated by the temperatures of the grease nodes based on the relationship of the grease temperature and viscosity, as well as the relationship of the viscosity and the film thickness. Findings By comparing the numerical calculation results of bearings under different working conditions, the influence of starvation lubrication on the oil film thickness, oil film drag force and rolling friction of bearings is discussed, and it is found that the numerical calculation results of the outer ring temperature of bearings under the starvation lubrication due to the consideration of temperature rise are closer to the experimental values. Originality/value This study reveals the dynamic characteristics of bearings under starvation lubrication, which is more practical and engineering guiding significance for the design of bearings, and introduces a new method and basis for the calculation of temperature rise of rolling bearings. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0208/

Significant improving magnetic properties and thermal conductivity of FeBSiPCNbCu nanocrystalline powder cores by designing novel ZnO insulating layer

As the application scenarios of soft magnetic composites (SMCs) tend to be high frequency, reducing their high-frequency core loss (Pcv) and improve the heat-sinking capability to avoiding thermal failure of electronic system are still greatly challenging. In present work, we successfully designed and prepared novel ZnO insulating layers on the surface of FeBSiPCNbCu nanocrystalline powders and discussed their growth processes. In addition, we investigated the effects of the ZnO insulating layers on the magnetic properties and heat-sinking capability of the FeBSiPCNbCu nanocrystalline magnetic powder cores (NMPCs) and explored the related mechanisms. The experimental results show that the hydrolysis of 1.75 wt% zinc acetate dihydrate under the coupling of 1 wt% polyvinylpyrrolidone forms uniform and thin ZnO insulating layers on the powders surface. The FeBSiPCNbCu@ZnO NMPCs annealed at 510 °C for 60 min exhibit excellent magnetic properties and superior heat-sinking capability with a low core loss of 698.4 mW/cm3 (20 mT, 2 MHz), high DC bias permeability of 68.3% (100 Oe) and heat conductivity coefficient of 2.22 W/(m•K) as compared with those of 859.8 mW/cm3, 57.1% and 1.86 W/(m•K), respectively, for the NMPCs without ZnO insulating layer.

Novel high-entropy (La0.35Gd0.35Y0.35Sm0.35Yb0.6)Zr2O7 thermal barrier coatings: Thermal cycling performance and failure behavior

The high-entropy ceramic (HEC) (La0.35Gd0.35Y0.35Sm0.35Yb0.6)Zr2O7 has emerged as a strong candidate for thermal barrier coatings (TBCs) due to its exceptional thermal properties. We investigated the thermal shock resistance of HEC–lanthanum zirconate (LZ)/yttria partially stabilized zirconia (YSZ) (i.e., the HEC coating) and LZ/YSZ (i.e., the LZ coating) double-ceramic-layer TBCs fabricated via plasma spraying. During thermal shock testing at 1100°C, the LZ coating failed after 60 ± 3 cycles, while the HEC coating had a considerably longer thermal cycling lifetime of 135 ± 5 cycles. The HEC coating’s superior performance is attributable to its enhanced oxygen barrier properties and inherent lattice disorder; the former reduced the growth rate of the thermally grown oxide, and the latter increased lattice defects and distortion. These factors helped improve the thermal expansion coefficient and reduced interlayer thermal stress accumulation. Furthermore, the higher fracture toughness of the HEC layer impeded crack propagation, collectively enhancing the TBCs’ thermomechanical shock resistance. These findings underscore the potential of (La0.35Gd0.35Y0.35Sm0.35Yb0.6)Zr2O7 as a robust material for extending the service life of TBCs in high-temperature environments.

Failure behavior of RE2M2O7/YSZ TBCs prepared by EB-PVD in gas thermal shock-CMAS corrosion environment

Three types of thermal barrier coatings (TBCs), YSZ, LZC/YSZ and GZO/YSZ, were deposited by EB-PVD. These coating systems were then subjected to thermal shock-CMAS corrosion testing using a high-temperature gas spray gun. The results demonstrate that the double-layer thermal barrier coatings exhibit excellent resistance to thermal shock-CMAS corrosion. Microstructural analysis revealed that the LZC/YSZ coating mitigated thermal damage owing to the formation of a sealing layer at the CMAS/LZC interface through high-temperature chemical interactions with CMAS. Compared to LZC/YSZ, the GZO/YSZ coatings showed greater resistance to CMAS-induced damage, which was associated with lower theoretical optical basicity values. This research provides valuable insights into the coupled thermal shock-CMAS corrosion failure mechanisms of TBCs on turbine blades and paves the way for new system-safe applications of TBCs.

Improvement of thermal damage resistance of SrAl2O4:Eu2+, Dy3+ persistent phosphor by a low temperature pre-annealing and its mechanism

SrAl2O4:Eu2+, Dy3+ as an excellent persistent phosphor has been widely applied in many fields. However, the high temperature induced thermal failure has always been a bottleneck problem restricting its long-term development. In this study, a simple pre-annealing method was utilized to improve the thermal damage resistance ability of SrAl2O4:Eu2+, Dy3+ persistent phosphors. After annealing at 900 °C, the afterglow duration time of the phosphor pre-annealed at 400 °C reached 233 min, which was twice longer than that of the phosphor without pre-annealing. An extrinsic vacancy defect migration theory at an elevated temperature was proposed to explain the interesting phenomenon. This study introduced a path to enhance the thermal stability of SrAl2O4:Eu2+, Dy3+ persistent phosphors and provided a thought to design persistent luminescence materials with desired thermal stability.

Thermal Monitoring of an Internal Combustion Engine for Lightweight Fixed-Wing UAV Integrating PSO-Based Modelling with Condition-Based Extended Kalman Filter

The internal combustion engines of long-endurance UAVs are optimized for cruises, so they are prone to overheating during climbs, when power requests increase. To counteract the phenomenon, step-climb maneuvering is typically operated, but the intermittent high-power requests generate repeated heating–cooling cycles, which, over multiple missions, may promote thermal fatigue, performance degradation, and failure. This paper deals with the development of a model-based monitoring of the cylinder head temperature of the two-stroke engine employed in a lightweight fixed-wing long-endurance UAV, which combines a 0D thermal model derived from physical first principles with an extended Kalman filter capable to estimate the head temperature under degraded conditions. The parameters of the dynamic model, referred to as nominal condition, are defined through a particle-swarm optimization, minimizing the mean square temperature error between simulated and experimental flight data (obtaining mean and peak errors lower than 3% and 10%, respectively). The validated model is used in a so-called condition-based extended Kalman filter, which differs from a conventional one for a correction term in section prediction, leveraged as degradation symptom, based on the deviation of the model-state derivative with respect to the actual measurement. The monitoring algorithm, being executable in real-time and capable of identifying incipient degradations of the thermal flow, demonstrates applicability for online diagnostics and predictive maintenance purposes.

Experimental investigation into thermal characteristics of subcooled flow boiling in horizontal concentric annuli for cooling ultra-fast electric vehicle charging cables

In an effort to reduce the charging time of electric vehicles (EVs), the thermal management of the charging system has emerged as one of the most urgent issues. The charging rate has been restricted to avoid thermal failure especially in charging cable. Recently, a direct contact cooling technique that utilizes subcooled flow boiling for charging cables has been proposed and has shown promising thermal management performance. However, there has been a lack of clear explanation regarding its thermal characteristics due to its intrinsically complicated flow features. This study investigates the thermal characteristics of subcooled flow boiling in a horizontally aligned concentric annular tube intended to simulate the direct contact cooling technique employed for charging cables. For the experimental investigation, the wall temperature measurements and high-speed flow visualization images acquired from the transparent test module annulus, with inner and outer diameters of 6.35 mm and 22.0 mm, were utilized. Three key axial thermal characteristics of subcooled flow boiling in annulus have been analyzed, and they are flow regime transition, variation of heat transfer mechanisms, and occurrence of critical heat flux (CHF). The transition of flow regimes and the variation of dominant heat transfer mechanisms in the axial direction are mutually influencing due to the coupled effects between the hydrodynamic and thermal characteristics of simultaneously developing flows. The flow regime changes from partially developed boiling (PDB) to fully developed boiling (FDB) as the intensities of nucleate boiling and bubble recondensation vary in the axial direction, while the dominant heat transfer mechanism shifts from single-phase convection to nucleate boiling, corresponding to the flow regime transition from PDB to FDB. The departure from nucleate boiling (DNB) type CHF is observed, manifested by the wavy interface propagating from the far downstream to the upstream region, and the intensities of nucleate boiling and bubble recondensation are also identified as the dominant parameters in determining the occurrence of CHF. Charging time estimation reveals that the proposed method can achieve an 80 % charge for 100-kWh EV batteries in 98 s, while maintaining the cable wire temperature below the safety limit of 80 °C. This strongly supports its potential as a promising thermal management technique for future ultra-fast charging systems.

The transient thermomechanical behavior of solid oxide fuel cell during the operation condition variations

Solid oxide fuel cell (SOFC) is a promising energy conversion technology with high efficiency, low emission and fuel flexibility. In practical and dynamic operation, the thermal stress at the interface of different layers can cause cracks or even thermal mechanical failure. This study investigates the transient thermomechanical behavior of SOFC under changing operating conditions. A three-dimensional dynamical model is developed by considering the electrochemical reaction, electron and ion transport, gas diffusion, heat and momentum transfer, and thermal-mechanical interaction. When the operating conditions vary, the time it takes for the thermal stress to reach a steady state is consistent with the time required for heat transfer to stabilize. The electrolyte layer is subjected to the maximum gradient of thermal stress change after the voltage is switched. With an increase in the inlet gas temperature, the change in the cell temperature can be divided into two stages: a rapid rise and a slow rise. Appropriate prolongation of the temperature rise time is beneficial to the thermal stability of SOFC. The increase in inlet gas temperature changes the distribution trend of cell temperature and thermal stress, while the 50 % reduction in cathode and anode inlet velocity changes its magnitude.

Lifetime prediction of copper pillar bumps based on fatigue crack propagation

2.5D package realizes the interconnection of multiple dies through Si interposers, which can greatly improve the data transmission rate between dies. However, its multi-layer structure and high package density also place higher reliability requirements on the interconnection structure. As a key structure for interconnection, copper pillar bump (CPB) has small size, high heat generation, and thermal mismatch with silicon chips. The thermal fatigue failure of CPB has gradually become the main failure mode in 2.5D package. Due to the small size of CPB and the large proportion of intermetallic compound (IMC) layers, the lifetime prediction method of spherical solder joints is no longer suitable for CPB. Therefore, it is necessary to establish a fatigue lifetime prediction method for CPB. This paper establishes a method for obtaining the lifetime of CPB based on the basic theory of fatigue crack propagation. Using the extended finite element simulation method, the crack propagation lifetime of CPB under thermal cycling was obtained, and the influence of different IMC layer thickness on the fatigue lifetime of CPB was analyzed. The results indicated that the fatigue lifetime of cracks propagating in the IMC layer is lower than that of cracks propagating in the solder layer, and an increase in the thickness of the IMC layer leads to a significant decrease in the fatigue lifetime of CPB. The lifetime prediction method for CPB proposed in this paper can be used for reliability evaluation of 2.5D package, and has certain reference value for the study of the lifetime of CPB.

Degradation mechanism of SiC diodes under thermal and irradiation stress

Abstract Silicon carbide (SiC)-based diodes are widely used due to their high temperature resistance. In this paper, breakdown voltage of 4H-SiC JBS diodes and capacitance-voltage of 4H-SiC MOS capacitors with identical interfacial structure were both measured at high temperature to study their interfacial properties. By analyzing the variation of interfacial properties, the correlation between thermal stress and failure mode of 4H-SiC JBS diodes was further established to reveal their degradation mechanism. During initial high temperature storage, interfacial negative effective charge density of 4H-SiC JBS diodes may increase, leading to the decrease of breakdown voltage. As storage time increases, interfacial charge density began reducing, resulting in the increase of breakdown voltage. Avalanche luminescence verifies that the variation of interfacial charge density under thermal stress led to the degradation of 4H-SiC JBS diodes and further affected their breakdown voltage. Finally, degradation mechanism of SiC-JBS, SiC-SBD and SiC-PIN diodes under irradiation stress was investigated. After irradiation, forward current of some SiC diodes increased at a small forward voltage. However, the reverse characteristics deteriorated obviously and even failed.

Theoretical approaches to study degradation in Li-ion battery cathodes: Crucial role of exchange and correlation

Abstract Li-ion batteries have become essential in energy storage, with demand rising steadily. Cathodes, crucial for determining capacity and voltage, face challenges like degradation in the form of thermal runaway and battery failure. Understanding these degradation phenomena is vital for developing mitigation strategies. Experimental techniques such as XAS, XPS, PES, UV–Vis, RIXS, NMR, and OEMS are commonly used, but theoretical modelling, particularly atomistic modelling with density-functional theory (DFT), provides key insights into the microscopic electronic behaviours causing degradation. While DFT offers a precise formulation, its approximations in the exchange-correlation functional and its ground-state, 0K limitations necessitate additional methods like ab initio molecular dynamics. Recently, many-body electronic structure methods have been used alongside DFT to better explain electron–electron interactions and temperature effects. This review emphasizes material-specific methods and the importance of electron–electron interactions, highlighting the role of many-body methods in addressing key issues in cathode degradation and future development in electron–phonon coupling methods. Graphical abstract

Series arc-induced internal short circuit leading to thermal runaway in lithium-ion battery

With the widespread implementation of battery energy storage systems (BESSs), significant attention has been focused on issues involving electrical safety. The series arc hazard caused by loose connectors between batteries has become a serious problem. However, research findings for the evolution process of the series arc and the related hazard principle are still unclear. Therefore, in this study we focus on the series arc at the negative terminal of a 20 Ah prismatic lithium-ion battery, establish an experimental platform for the arc, and conduct research on the hazards process. Our results indicate that the arc can induce the thermal failure of the battery when the power supply voltage is 300 V and the circuit current is 15 A. Through a battery voltage analysis, computed tomography scans, and jellyroll disassembly, we uncover the evolution process and hazard laws of series arcs and clarify the failure pathways of arc-induced battery faults. The hotspots formed by arc melt the casing and cause electrolyte leakage. In addition, the heat transfer from the battery terminal to the jellyroll induces separator melting and internal short circuits in batteries. These cause an internal short circuit between the anode and the cathode, as well as combustion of the leaked electrolyte, which give rise to distinct thermal runaway behavior under different states of charge. By comparing runaway behavior with failures triggered by external heating, we clarify that the series arc is a novel risk factor that induces failure. This study addresses the gap in research related to arc effects on battery safety. This is crucial to the development of safe battery systems that do not present arc hazards.

Electric-Thermal Analysis of Power Supply Module in Graphitization Furnace

Graphite, a key anode material in lithium-ion batteries, primarily relies on the Acheson graphitization furnace (AGF) for production. This research focuses on the power supply module of the AGF, particularly the electrodes and their power transmission clamps. A three-dimensional transient electric-thermal-fluid coupling model was developed to numerically analyze the temperature and electric field distributions during operation. The study revealed that heat conduction through furnace electrodes dominates temperature rise. Notably, clamping plates within transmission clamps exhibit high temperatures and gradients, posing a thermal failure risk. Efficient cooling plate design with liquid-cooled channels is crucial for temperature control. Additionally, maintaining high electrode temperatures reduces resistivity, lowering power consumption in the power supply module. This study provides insights into optimizing AGF power supply module design, emphasizing the importance of effective cooling strategies for clamping plates and the benefits of maintaining elevated electrode temperatures for energy efficiency.

Acoustic and thermal response characteristics and failure mode of gas-bearing coal–rock composite structure under loading

Exploring the characteristics of the instability and failure processes of gas-bearing coal and rock is crucial for monitoring and predicting mine gas accidents. Thus, a real gas environment was simulated based on a self-developed gas–solid coupling infrared observation system. The acoustic–thermal response characteristics and failure mode of the gas-bearing coal–rock composite structure were studied. The results showed the following: (1) From the plastic stage, the average infrared radiation temperature of the coal increased significantly. The variances of differential infrared temperature (VDIRT) of the combination and coal started to mutate approximately 30 s before the peak, and the b value of the combination began to fluctuate frequently, while the VDIRT of rock remained approximately 2.128 × 10−4 throughout the process. (2) When stress was about to peak, a clear temperature boundary formed between coal and rock. Acoustic emissions with high energy were mainly concentrated at the interface and inside the coal. (3) The early plastic stage was dominated by high-frequency, low-amplitude events. In the post-peak stage and late plastic stage, the proportion of events with 80–90 dB amplitude rose, and there was a significant increase in low-frequency, high-amplitude events. (4) As the loading proceeded, the density and area gradually increased and tended to move toward the shear crack region. The distribution range of the rise time/amplitude expanded from 0–12 ms/V at the beginning of the loading to the range of 0–60 ms/V in the post-peak stage.

Multi-scenario failure diagnosis for lithium-ion battery based on coupling PSO-SA-DBSCAN algorithm

The battery failure diagnosis methods are the main algorithms for online battery management system, but the conventional methods are mainly developed from calibrated thresholds detection, which will suffer from the degradation for full-lifespan operation and have no consideration of utilization for battery system information. Here we show innovative diagnosis methods for detecting battery failure both from online battery management system and cloud monitoring platform based on a particle swarm optimization-simulated annealing- density based spatial clustering of applications with noise (PSO-SA-DBSCAN) algorithm. By using the battery electrochemical impedance spectroscopy and voltage, the proposed method can solve the problem of battery abnormal degradation diagnosis, thermal runaway diagnosis and sampling failure diagnosis. Compared against conventional methods, the proposed method has less reliance on parameterization with better precision, which is validated from commercial prismatic cells and cloud data from a 117 serial-cell pack, with high accuracy and lower misinformation compared against conventional detecting methods, confirming the actual effectiveness for online battery pack.

Deep Neural Network-Based Temperature Mapping Technique for Heat Sink on Electronic Devices Using Local Thermocouple Sensors

ABSTRACT Heat generated by electronic devices can lead to thermal deformation, damage, and fatigue failure, underscoring the importance of monitoring heat distribution. This study introduces an artificial neural network using two thermocouples for cost-effective temperature distribution prediction. Experimental data from heated systems on chip with attached heat sinks were used for training and validation, integrating thermocouple measurements and infrared camera data. The method’s applicability was verified across four different heat sinks. Additionally, finite element analysis compared stress and strain based on predicted and actual temperature distributions, addressing conventional limitations that focus solely on temperature validation. Furthermore, the temperature of any coordinate could be output by including the coordinate as an input of neural networks, eliminating the hassle of re-constructing or learning the DNN to obtain the temperature of the desired coordinate. Results showed that the temperature distribution could be predicted with high accuracy (over 0.95), and the maximum error rate for stress and strain predictions was 7% in the worst case. This confirmed the feasibility of artificial neural networks to predict the temperature distribution using a minimal number of sensors and ensure robust performance even if the heat sink changes.

Dual neural network for contact temperature and cooling state monitoring in water-lubricated bearings

Harsh operating conditions subject the water-lubricated stern bearings of a ship to a non-uniform stress field, leading to frequent boundary lubrication between the bearing and shaft. Poor lubrication results in local temperature rise due to friction heat, leading to heat aging or even carbonization of the bearings. This study proposes a novel universal monitoring approach based on the internal temperature of water-lubricated bearings (WLBs). Radial basis function neural networks (RBFNN) were established to evaluate the surface temperature and cooling statuses of the bearing surface during rubbing, in which simulation results obtained from a temperature model were used as a training set. The accuracy of the simulation results and prediction model was verified through experimental data. The results showed that the maximum error of predicted contact surface temperatures is only 0.84 °C, 0.02 °C, and 1.00 °C in MAE, MAPE, and RMSE, respectively. The accuracy of cooling conditions identification can be achieved at 91.7 % with 600 s of continuous temperature data. The scheme proposed in this study can effectively predict thermal failures of water-lubricated bearings without requiring extensive experimentation, which promotes the development of intelligent water-lubricated bearings.

Safety and behavior of implantable electronic devices during cremation

BackgroundThe current standard of practice for cremating patients with cardiac implantable electronic devices (CIEDs) is surgical explantation before cremation to mitigate the risk of device explosion. This surgery may conflict with patient or family beliefs, whereas cremation of CIEDs may create occupational hazards. ObjectiveThis study sought to establish an ex vivo model for screening CIED behavior during cremation. MethodsSeven CIEDs underwent testing including projectile/sound testing, impact testing, and gas analysis. In the projectile test, devices were heated until thermal failure (explosion) and filmed with a high-speed camera and microphone. For impact testing, brick structures were built to assess damage after explosion. Gas chromatography–mass spectrometry identified released gases. Findings were compared with occupational health standards, where available. ResultsThe implantable loop recorder and leadless pacemaker produced minimal kinetic energy and impact risk with thermal failure. The remaining devices demonstrated explosive disintegration at thermal temperatures <500°C. The pacemakers and implantable cardiac defibrillators produced sound levels >120 dB and resulted in damage to brick structures. Small quantities of benzene and hydrogen fluoride were produced but at quantities within acceptable occupational exposure limits in a cremation chamber. ConclusionAll tested CIEDs experienced explosion at temperatures below crematorium standards. The smallest devices produced minimal risk of damage or injury, suggesting that they may safely remain in situ during cremation, whereas the larger devices produced more kinetic energy, testing chamber damage, and louder explosions, suggesting potential risk with cremation. Cadaveric testing in full-sized cremation chambers is required to determine real-world risk.