Search Results (105)

Lithium-ion batteries suffer from severe capacity fading and start-up failure at low temperatures owing to restricted Li⁺ transport and deteriorated interfacial kinetics. To enable rapid and safe activation under such conditions, this study designs a microwave-driven dual-layer leakage-proof composite phase-change module (EPG–BN–CF–PAG), comprising an epoxy–graphene–boron nitride outer encapsulation and a ceramic fiber–boron nitride porous inner scaffold that adsorbs a paraffin–graphene phase-change core. The synergy between the dense outer shell and the internal adsorption framework affords excellent shape stability, with an enthalpy retention exceeding 95% and no visible leakage after 20 heating–cooling cycles. Owing to the strong microwave-absorption capability of graphene, the module can be rapidly heated from −10 °C to ~60 °C within 60 s while establishing a homogeneous and stable temperature field. Combined simulations and experiments show that the module efficiently transfers heat to a lithium-ion cell, raising its temperature from −10 °C to ~30 °C within 60 s and thus bringing it into a practical operating window. Electrochemical impedance spectroscopy further reveals that the thermally induced activation markedly improves interfacial kinetics, reducing the bulk resistance from 500 Ω to 30 Ω and the charge-transfer resistance from 800 Ω to 30 Ω. This microwave-driven phase-change heating strategy features ultrafast response, excellent anti-leakage performance, and favorable thermal properties, providing an engineering-feasible thermal-management solution for the rapid cold start of lithium-ion batteries under extremely low-temperature conditions. Full article

Thermal control represents one of the most important parameters influencing the safety and reliability of lithium-ion batteries, especially at high rates required for modern electric vehicles. The present paper investigates the thermal and electrothermal performance of a lithium iron phosphate (LiFePO₄) battery pack using a combination of experimental, statistical, and numerical methods. The 8S5P module was assembled and examined under load tests of 200, 400, and 600 W with and without active air-based cooling. The findings indicate that cooling reduced cell surface temperature by up to 10 °C and extended discharge time by 7–16% under various load conditions, emphasizing the effect of thermal management on battery performance and safety. In order to more systematically investigate the impact of ambient temperature and load, a RSM study with a central composite design (CCD; 13 runs) was performed, resulting in two very significant quadratic models (R² > 0.98) for peak temperature and discharge duration prediction. The optimum conditions are estimated at a 200 W load and an ambient temperature of 20 °C. Based on experimentally determined parameters, a finite-element simulation model was established, and its predictions agreed well with the measured results, which verified the analysis. Integrating measurements, statistical modeling, and simulation provides a tri-phase methodology to date for determining and optimizing battery performance under the electrothermal dynamics of varied environments. Full article

Defective graphene has emerged as a promising strategy to enhance electrochemical performance of pristine graphene (p-Gr) as anodes in lithium-ion batteries (LIBs). Herein, we perform a comprehensive first-principles study based on density functional theory (DFT) to systematically investigate the Li adsorption, charge transfer, and diffusion behaviors of p-Gr and defective graphene (d-Gr) with single vacancy (SV Gr) and double vacancy (DV5-8-5 Gr) defects, aiming to clarify the mechanism by which defects modulate Li storage performance. Structural optimization reveals that SV Gr undergoes notable out-of-plane distortion after Li adsorption, while DV5-8-5 Gr retains planar geometry but exhibits more significant C-C bond length variations compared to p-Gr. Binding energy results confirm that defects enhance Li adsorption stability, with DV5-8-5 Gr showing the strongest Li–graphene interaction, followed by SV Gr and p-Gr. Bader charge analysis and charge density difference plots further validate that defects enhance charge transfer from Li ions to graphene. Using the nudged elastic band (NEB) method, we find that defects reduce Li diffusion barriers: DV5-8-5 Gr exhibits a lower barrier than p-Gr. Our findings demonstrate that DV5-8-5 Gr exhibits the most favorable Li storage performance, providing a robust theoretical basis for designing high-performance graphene anodes for next-generation LIBs. Full article

This paper presents a case study of research-based learning (RBL) implemented in an undergraduate engineering course through a module titled “State-of-Charge Monitoring of Li-Ion Batteries Using Thermographic Surface-Temperature Measurements”. The experiment involved 10 third-year engineering students and employed a single-group pre- and post-test design and a lecturer interview. The module provided students with an authentic research experience using advanced laboratory equipment. The study examines students’ attitudes, satisfaction, and development of research skills, as well as the lecturer’s perspective on the advantages and challenges of RBL. While the study had a limited timeframe and specific design characteristics, the findings could benefit researchers interested in integrating RBL. Results indicated that students showed initial interest, primarily seeking practical knowledge and skills. By the end of the experiment, they reported that RBL fostered high motivation and strengthened their sense of commitment, responsibility, and initiative. Despite the students’ enthusiasm and the lecturer’s motivation, the results show that preparing and implementing RBL required significant time and effort on the lecturer’s part. The students’ lack of prior knowledge in research activities and the limited time frame posed considerable challenges. Recommendations include implementing RBL over a longer period and involving additional educators to enhance student support. Full article

Home energy management systems have emerged as a crucial solution for enhancing energy efficiency, reducing carbon emissions, and facilitating the integration of renewable energy sources into homes. To fully realize their potential, these systems’ performance must be optimized, which involves addressing multiple objectives, such as minimizing costs and environmental impact. The Pareto frontier is a tool widely adopted in multi-objective optimization within home energy management systems’ operation, where a range of optimal solutions are produced. This study uses the Pareto curve to optimize the operational performance of home energy management systems, considering the state health of the battery to determine the best answer among the optimal solutions in the curve. The main reason for considering the state of health is the effects of the battery’s operation on the performance of energy systems, especially for long-term optimization outcomes. In this study, the performance of the battery is measured through a physical model named PyBaMM that is tuned based on swarm intelligence techniques, including the Whale Optimization Algorithm, Grey Wolf Optimization, Particle Swarm Optimization, and the Gravitational Search Algorithm. The proposed framework automatically identifies the optimal solution out of the ones in the Pareto curve by comparing the performance of the battery through the tuned physical model. The effectiveness of the proposed algorithm is demonstrated for a home, including four distinct energy carriers along with a 12 V 128 Ah LFP chemistry Li-ion battery module, where the overall cost and carbon emissions are the metrics for comparisons. Implementation results show that tuning the physical model based on the Whale Optimization Algorithm reaches the highest accuracy compared to the other methods. Moreover, considering the state of health of the battery as the selecting criterion will improve home energy management systems’ performance, particularly in long-term operation models, because it guarantees a longer battery lifespan. Full article

High temperatures during charge–discharge cycles pose a significant threat to the safety and capacity of lithium-ion batteries by accelerating solid–electrolyte interphase (SEI) growth. Conversely, elevating the temperature during charging enhances Li-ion transport and suppresses lithium plating, suggesting an asymmetric temperature modulation (ATM) strategy in which cells are charged at elevated temperatures and discharged at room temperature to mitigate degradation under extreme fast-charging conditions. In this study, a one-dimensional electrochemical model incorporating key side reactions—SEI formation, lithium plating, and lithium stripping—is developed to analyse the ageing behaviour of plug-in hybrid electric vehicle (PHEV) cells under ATM operation. Within the present modelling framework and for the investigated temperature and current ranges, lithium plating is found to exert only a modest influence on the SEI growth rate, and the capacity degradation associated with SEI formation at a given temperature follows a unique time dependence that shows only a weak sensitivity to the charging rate. A phenomenological hill-shaped dependence of plating reversibility on the state of charge (SOC) is implemented based on experimental observations. The simulation results show good agreement with experimental data for PHEV cells operated under ATM, reproducing a capacity retention of about 80% after 1000 cycles at a charging temperature of 49 °C. Full article

In this study, a battery case was developed using a 3D (three dimensional)-printed composite of hexagonal boron nitride (hBN) and polylactic acid (PLA) to enhance the thermal performance of lithium-ion battery (LiB) modules. A 10 wt.% amount of hBN was incorporated into the PLA matrix to improve the composite’s thermal conductivity while maintaining electrical insulation. A 3S2P (3 series and 2 parallel) battery configuration was initially evaluated based on the results of a baseline study for comparison and subsequently subjected to a newly developed test procedure to assess the thermal behavior of the designed case under identical environmental conditions. Initially, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were utilized for material characterization, and their results verified the successful integration of hBN by confirming its presence in the hBN-PLA composite. In thermal tests, experimental results revealed that the fabricated hBN-PLA composite battery case significantly enhanced heat conduction and reduced surface temperature gradients compared to the previous baseline study with no case. Specifically, the maximum cell temperature (T_max) decreased from 48.54 °C to 45.84 °C, and the temperature difference (ΔT) between the hottest and coldest cells was reduced from 4.65 °C to 3.75 °C, corresponding to an improvement of approximately 20%. A 3S2P LiB module was also tested under identical environmental conditions using a multi-cycle charge–discharge procedure designed to replicate real electric vehicle (EV) operation. Each cycle consisted of sequential low and high discharge zones with gradually increased current values from 2 A to 14 A followed by controlled charging and rest intervals. During the experimental procedure, the average ΔT between the cells was recorded as 2.38 °C, with a maximum value of 3.50 °C. These results collectively demonstrate that the 3D-printed hBN-PLA composite provides an effective and lightweight passive cooling solution for improving the thermal stability and safety of LiB modules in EV applications. Full article

This review investigates how cell form factors (cylindrical, prismatic, and pouch) and electrode architecture (jelly-roll, stacked, and blade) influence the performance, safety, and manufacturability of lithium-ion batteries (LIBs) across the main commercial chemistries LiFePO₄ (LFP), Li (NiMnCo)O₂ (NMC), LiNiCoAlO₂ (NCA), and LiCoO₂ (LCO). Literature, OEM datasheets, and teardown analyses published between 2015 and 2025 were examined to map the interdependence among geometry, electrode design, and electrochemical behavior. The comparison shows trade-offs among gravimetric and volumetric energy density, thermal runaway tolerance, cycle lifespan, and cell-to-pack integration efficiency. LFP, despite its lower nominal voltage, offers superior thermal stability and a longer cycle life, making it suitable for both prismatic and blade configurations in EVs and stationary storage applications. NMC and NCA chemistries achieve higher specific energy and power by using jelly-roll architectures that are best suited for tabless or multi-tab current collection, enhancing uniform current distribution and manufacturability. Pouch cells provide high energy-to-weight ratios and flexible packaging for compact modules, though they require precise mechanical compression. LCO remains confined to small electronics owing to safety and cost limitations. Although LFP’s safety and affordability make it dominant in cost-sensitive applications, its low voltage and energy density limit broader adoption. LiMnFePO₄ (LMFP) cathodes offer a pathway to enhance voltage and energy while retaining cycle life and cost efficiency; however, their optimization across various form factors and electrode architecture remains underexplored. This study establishes an application-driven framework linking form factors and electrode design to guide the design and optimization of next-generation lithium-ion battery systems. Full article

The current energy transition highlights the importance not only of energy production, but also of its efficient storage, for which lithium-ion batteries are currently the leading technology. In many applications, these devices operate outdoors at temperatures below 0 °C, and consequently, their performance is reduced due to the lower mobility of the ions. With the aim of evaluating this decrease in performance, measurements were carried out on a commercial LiFePO₄ module in the temperature range −20–+55 °C. The results show that the battery capacity decreases by 15% compared to the value measured at room temperature when the operating temperature drops to approximately −10 °C, and by 35% at approximately −20 °C. The paper also introduces a modified version of the Arrhenius kinetic model that allows for the analytical evaluation of the change in battery capacity as a function of temperature. The modified model proposes a quadratic dependence of the activation energy on the temperature through a temperature coefficient that for the two tested modules is equal to 8.0 × 10⁻⁵ eV/K² and 6.7 × 10⁻⁵ eV/K², respectively. Full article

Fault diagnosis of battery energy storage systems (BESSs) in dynamic operating conditions presents significant challenges due to complex spatiotemporal patterns and measurement noise. This research proposes a novel thermal fault diagnosis framework for BESSs based on Bayesian inference and a Kalman filter. Firstly, PLS-based spatiotemporal feature extraction is designed to capture temporal dependencies. Based on Bayesian global exploration and Kalman real-time weight adaptation, a dual-stage optimization strategy is proposed to derive a multiscale detection index with the dominant statistic, the residual statistic, and the module voltage similarity. A time window-based cumulative contribution strategy is constructed for precise cell localization. Finally, the experimental validation on a Li-ion battery pack demonstrates the proposed method’s superior performance: 96.92–99.90% anomaly detection rate, false alarm rate ranging from 0.10% to 7.22%, detection delays of 1–27 s, and 100% accuracy in fault localization. The proposed framework provides a comprehensive solution for safety management of BESSs and is significant for battery life and energy sustainability. Full article

Graphene, owing to its exceptional mechanical properties and interfacial modulation capability, is considered an ideal material for enhancing the interfacial strength and damage resistance during the fabrication of ultra-thin lithium foils. Although previous studies have demonstrated the reinforcing effects of graphene on lithium metal interfaces, most analyses have been restricted to single-temperature or idealized substrate conditions, lacking systematic investigations under practical, multi-temperature environments. Consequently, the influence of graphene coatings on lithium-ion conductivity and mechanical stability under real thermal conditions remains unclear. To address this gap, we employ LAMMPS-based molecular dynamics simulations to construct atomic-scale models of pristine lithium and graphene-coated lithium (C/Li) interfaces at three representative temperatures. Through comprehensive analyses of dislocation evolution, root-mean-square displacement, frictional response, and lithium-ion diffusion, we find that graphene coatings synergistically alleviate interfacial stress, suppress crack initiation, reduce friction, and enhance ionic conductivity, with these effects being particularly pronounced at elevated temperatures. These findings reveal the coupled mechanical and electrochemical regulation imparted by graphene, providing a theoretical basis for optimizing the structure of next-generation high-performance lithium metal anodes and laying the foundation for advanced interfacial engineering in battery technologies. Full article

Battery cell balancing is crucial in series-connected lithium-ion packs to maximize usable capacity, ensure safe operation, and prolong cycle life. This paper presents a comprehensive study and a novel adaptive duty-cycled hybrid balancing system that combines passive bleed resistors and an active switched-capacitor (SC) balancer, specifically designed for a 4-cell series-connected battery pack. This work also explored open circuit voltage (OCV)-driven adaptive pulse-frequency modulation (PFM) active balancing to achieve higher efficiency and better balancing speed based on different system requirements. Finally, this paper compares passive, active (SC-based), and adaptive duty-cycled hybrid balancing strategies in detail, including theoretical modeling of energy transfer and efficiency for each method. Simulation showed that the adaptive hybrid balancer speeds state-of-charge (SoC) equalization by 16.24% compared to active-only balancing while maintaining an efficiency of 97.71% with minimal thermal stress. The simulation result also showed that adaptive active balancing was able to achieve a high efficiency of 99.86% and provided an additional design degree of freedom for different applications. The results indicate that the adaptive hybrid balancer offered an excellent trade-off between balancing speed, efficiency, and implementation simplicity for 4-cell Li-ion packs, making it highly suitable for applications such as high-voltage portable chargers. Full article

A novel architectural design is proposed to optimize the thermal management of lithium-ion batteries (LiBs) through a software-enabled switching mechanism. This approach addresses critical challenges such as hot-spot generation, peak temperature rise, and uneven thermal distribution—issues commonly observed in conventional single-terminal battery modules (STBMs). The proposed dual-terminal configuration integrates an enhanced battery pack structure with a software-enabled switching algorithm that identifies the 50% depth of discharge (DoD) and toggles the current path between two terminals to supply the load. Correspondingly, the module also incorporates the division of four thermal zones and four regions concept in the battery module (BM). Experiments were conducted to evaluate the performance of the proposed model at five different C-rates: 0.5C, 0.75C, 1C, 1.25C, and 1.5C. The results demonstrate that the software-enabled dual-terminal switching (Se-DTS) consistently outperforms the STBM across three key aspects. First, in terms of peak temperature, Se-DTS achieved reductions of 19.33%, 17.83%, and 12.72% at C-rates of 1C, 1.25C, and 1.5C, respectively. Second, in thermal distribution, Se-DTS improved performance, with an 86.1% reduction at 1.25C. Third, regarding hot-spot reduction, improvements of 100% (regional level) and 72.22% (zonal level) were observed at 1.25C, while at 1.5C, an 80% improvement was achieved at the zonal level, without using a cooling system. Full article

Due to their high energy density and power potential, 21700 lithium-ion battery cells are a widely used technology in hybrid and electric vehicles. Efficient thermal management is essential for maximizing the performance and capacity of Li-ion cells in both low- and high-temperature operating conditions. Optimizing thermal management systems remains critical, particularly for long-range and weight-sensitive applications. In these contexts, passive heat dissipation emerges as an ideal solution, offering effective thermal regulation with minimal additional system weight. This study aims to deepen the understanding of passive heat dissipation in 21700 battery cells and optimize their performance. Special emphasis is placed on analyzing heat transfer and the relative contributions of convective and radiative mechanisms under varying temperature and discharge conditions. Laboratory experiments were conducted under controlled environmental conditions at various discharge rates, ranging from 0.5×C to 5×C. A 3D-printed polymer casing was applied to the cell to enhance thermal dissipation, designed specifically to increase radiative heat transfer while minimizing system weight and reliance on active cooling solutions. Additionally, a numerical model was developed and optimized using experimental data. This model simulates convective and radiative heat transfer mechanisms with minimal computational demand. The optimized numerical model is intended to facilitate further investigation of the cell envelope strategy at the module and battery pack levels in future studies. Full article

Polymer electrolytes (PEs) provide enhanced safety for high–energy–density lithium metal batteries (LMBs), yet their practical application is hampered by intrinsically low ionic conductivity and insufficient electrochemical stability, primarily stemming from suboptimal Li⁺ solvation environments and transport pathways coupled with slow polymer dynamics. Herein, we demonstrate a molecular design strategy to overcome these limitations by regulating the Li⁺ solvation structure through the synergistic interplay of conventional Lewis acid–base coordination and engineered hydrogen bond (H–bond) networks, achieved by incorporating specific H–bond donor functionalities (N,N′–methylenebis(acrylamide), MBA) into the polymer architecture. Computational modeling confirms that the introduced H–bonds effectively modulate the Li⁺ coordination environment, promote salt dissociation, and create favorable pathways for faster ion transport decoupled from polymer chain motion. Experimentally, the resultant polymer electrolyte (MFE, based on MBA) enables exceptionally stable Li metal cycling in symmetric cells (>4000 h at 0.1 mA cm⁻²), endows LFP|MFE|Li cells with long–term stability, achieving 81.0% capacity retention after 1400 cycles, and confers NCM622|MFE|Li cells with cycling endurance, maintaining 81.0% capacity retention after 800 cycles under a high voltage of 4.3 V at room temperature. This study underscores a potent molecular engineering strategy, leveraging synergistic hydrogen bonding and Lewis acid–base interactions to rationally tailor the Li⁺ solvation structure and unlock efficient ion transport in polymer electrolytes, paving a promising path towards high–performance solid–state lithium metal batteries. Full article