Search Results (96)

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

Iron phosphate (FePO₄·2H₂O) was synthesized via anodic oxidation using nickel–iron alloy composition simulates from laterite nickel ore as the anode and graphite electrodes as the cathode, with phosphoric acid serving as the electrolyte. A uniform experimental design was employed to systematically optimize the synthesis parameters including voltage, electrolyte concentration, electrolysis time, and degree of acidity or alkalinity (pH). The results indicate that the addition of cetyltrimethylammonium bromide (CTAB) surfactant effectively modulated the morphology of the anodic oxidation products. The optimized conditions were determined to be an electrolyte concentration of 1.2 mol/L, a voltage of 16 V, a pH of 1.6, an electrolysis time of 8 h, and a 3% CTAB addition. Under these conditions, the synthesized FePO₄·2H₂O exhibited enhanced performance as a lithium-ion battery precursor. Specifically, the corresponding LiFePO₄/C cathode delivered an initial discharge capacity of 157 mA h g⁻¹ at 0.2 C, retaining 99.36% capacity after 100 cycles. These findings provide valuable insights and theoretical foundations for the efficient preparation of iron phosphate precursors, highlighting the significant impact of optimized synthesis conditions on the electrochemical performance of lithium iron phosphate. Full article

Li-rich Mn-based cathode materials are considered potential cathode materials for next-generation lithium-ion batteries due to their outstanding theoretical capacity and energy density. Nonetheless, challenges like oxygen loss, transition metal migration, and structural changes during cycling have limited their potential for commercialization. The work in this study employed a straightforward heat treatment to generate oxygen vacancies. This process led to the development of a spinel phase on the surface, which improved Li⁺ diffusion and boosted the electrochemical performance of Li-rich Mn-based oxides. The results demonstrate that the treated Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ exhibits an initial specific capacity of 247 mAh·g⁻¹ at 0.2C, as well as a reversible capacity of 224 mAh·g⁻¹ after 100 cycles, with a capacity retention of 90.7%. The voltage decay is 1.221 mV per cycle under 1C long-term cycling conditions, indicating excellent cycling stability and minimal voltage drop. Therefore, this strategy of engineering through nanoscale oxygen vacancies provides a new idea for the development of high-stability layered oxide anodes and provides a reference for the development and application of new energy materials. Full article

The formation of unstable solid electrolyte interphases (SEIs) on the surface of lithium metal anodes poses a significant barrier to the commercialization of lithium metal batteries (LMBs). Rational modulation of solvation structures within the electrolytes emerged as one of the most effective strategies to enhance interfacial stability in LMBs; however, this approach often compromises the structural stability of the bulk electrolyte. Herein, we present an innovative method that improves interface stability without adversely affecting the bulk electrolyte’s structural stability. By employing ZSM molecular sieves as efficient ion channels on the lithium metal anode surface—termed ZSM electrolytes—a more aggregated solvation structure is induced at the lithium metal interface, resulting in an anion-rich interphase. This anion-enriched environment promotes the formation of an SEI derived from anions, thereby enhancing the stability of the lithium metal interface. Consequently, Li||Cu cells utilizing the ZSM electrolyte achieve an average coulombic efficiency (CE) of 98.76% over 700 h. Moreover, LiFePO₄||Li batteries exhibit stable cycling performance exceeding 900 cycles at a current density of 1 C. This design strategy offers robust support for effective interfacial regulation in lithium metal batteries. Full article

Efficient and safe charging of lithium-ion batteries is essential for maximizing their lifespan and performance. This paper presents the design and implementation of a microcontroller-based Li-ion battery charger that employs real-time monitoring, adaptive charging strategies, and built-in safety mechanisms. The system integrates a CC/CV charging approach with automatic current regulation, overcharge protection, and reverse polarity detection. A current sensor module ensures continuous monitoring, while an LCD interface provides real-time feedback on charging parameters. Experimental validation was conducted using multiple Li-ion cells in various conditions, like new, aged, and deeply discharged, to evaluate charging behavior and safety under different scenarios. The system successfully regulated current and voltage, managed preconditioning for low-voltage cells, and transitioned smoothly between charging phases. A key contribution of this work is the development of a low-cost, microcontroller-based platform that enables flexible implementation and testing of diverse charging strategies. Its open-source architecture and modular design make it highly suitable for research, educational use, and experimental development in battery management systems. Future enhancements may include the integration of adaptive algorithms based on internal resistance and temperature, enabling smarter and more efficient charging. Full article

This paper proposes the sizing optimization method and energy management strategy for a stationary hybrid energy storage system dedicated to a DC traction power supply system. The hybrid energy storage system consists of two modules—a supercapacitor, mainly dedicated to regenerative energy utilization, and a Li-ion battery, aimed to peak power reduction. The sizing method and energy management strategy proposed in this paper aim to reduce the aging effect of lithium-ion batteries. It is shown that the parameters of both modules could be sized independently. The supercapacitor module parameters are sized based on the results of a simulation determining the regenerative power, resulting in limited catenary receptivity. The simulation model of the DC electrification system is validated by comparing the results of the simulation with the measurements of 15 min average power in a 24 h cycle as average values of one year. The battery module is sized based on the statistical data of 15 min substation power value occurrences. The battery energy capacity, its maximum discharge C-rate, and the conditions determining its operation are optimized to achieve the maximum ratio of annual income resulting from peak power reduction to annual operating cost resulting from the battery aging process and total life cycle. The case study prepared for a typical 3 kV DC substation with mixed railway traffic shows that peak power could be reduced by ~1 MW, giving a ~10-year payback period for battery module installation, while the energy consumption could be decreased by 1.9 MWh/24 h, giving a ~7.5-year payback period for supercapacitor module installation. The payback period of the whole energy storage system (ESS) is ~8.4 years. Full article

Thermal management of lithium-ion batteries is crucial for enhancing the performance and safety of electric vehicles. This study proposes a novel liquid cooling plate featuring gradually varied circular notched fins (GV-CNF) to improve the thermal management of a commercial LiFePO₄ battery. The results indicate that GV-CNF provides a more uniform temperature distribution, a lower T_a, and a reduced ∆P compared to circular fins under identical conditions, leading to a 41.1% improvement in the comprehensive performance evaluation indicator (TP). Notably, the value of TP increases with the height of the coolant channel; however, when the channel height exceeds 4 mm, the change in TP value becomes minimal. Afterward, further studies were conducted to investigate the effects of different inlet–outlet configurations on the cooling performance. The single-inlet, dual-outlet configuration (Type III) for the liquid cooling plate not only reduces the T_a value but also exhibits the lowest ∆P and a smaller high-temperature region. Additionally, when the outlet spacing (L) is 81 mm, the lowest T_a recorded is 27.87 °C, and the ∆P is 3.13 Pa, indicating that this is the best outlet spacing. Additionally, comparative analysis of GV-CNF with serpentine-channel and circular-fin cooling structures reveals that the GV-CNF design effectively reduces the maximum temperature of the battery module, minimizes localized heat accumulation, and maintains low energy consumption, demonstrating superior overall thermal performance. Full article

Temperature is a crucial parameter for ensuring the long lifespan and safe operation of lithium-ion batteries (LiBs). An efficient battery thermal management system (BTMS) tries to maintain temperature in between optimum limits. Despite some disadvantages, air-cooled BTMSs are still preferred due to their advantages such as light weight, simple design, low cost, and ease of maintenance. This study experimentally evaluated a fan-assisted BTMS for the purpose of cooling a 4S2P battery module that includes 18650 type cells. The battery module was initially tested with no cooling system to observe the temperature characteristics of the module, followed by testing with forced air cooling using a fan. Experiments were also conducted with perforated plates installed between the fan and the module to see their effects on the thermal behaviors. Tests were initiated when the ambient temperature was approximately 25 °C and the discharges were carried out by drawing constant currents of 4 A, 8 A, 12 A, and 16 A from the module via an electronic load. The results of this study highlighted the importance of an effective BTMS in ensuring battery safety and performance across different operational conditions. While all tested cooling configurations maintained acceptable temperature levels at lower discharge currents (4 A and 8 A), they struggled to do so at higher currents (12 A and 16 A). Among them, the Fan–HC mode demonstrated the highest efficiency, reducing the maximum temperature (T_max) by 38.82% at 12 A and 28.89% at 16 A compared to the no-cooling scenario. Moreover, it ensured a more uniform temperature distribution within the module. These findings emphasize the necessity of optimized cooling strategies, particularly for high-power applications. Full article

The rapid rise in the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has opened the door for diverse potential applications in powering indoor Internet of Things (IoT) devices. An energy harvesting system (EHS) powered by a PSC module with a backup Li-ion battery, which stores excess power at moments of high irradiances and delivers the stored power to drive the load during operation scenarios with low irradiances, has been designed. A DC-DC boost converter is engaged to match the voltage of the PSC and Li-ion battery, and maximum power point tracking (MPPT) is achieved by a perturb and observe (P&O) algorithm, which perturbs the photovoltaic (PV) system by adjusting its operating voltage and observing the difference in the output power of the PSC. Furthermore, the charging and discharging rate of the battery storage is controlled by a DC-DC buck–boost bidirectional converter with the incorporation of a proportional–integral (PI) controller. The bidirectional DC-DC converter operates in a dual mode, achieved through the anti-parallel connection of a conventional buck and boost converter. The proposed EHS utilizes DC-DC converters, MPPT algorithms, and PI control schemes. Three different case scenarios are modeled to investigate the system’s behavior under varying irradiances of 200 W/m², 100 W/m², and 50 W/m². For all three cases with different irradiances, MPPT achieves tracking efficiencies of more than 95%. The laboratory-fabricated PSC operated at MPP can produce an output power ranging from 21.37 mW (50 W/m²) to 90.15 mW (200 W/m²). The range of the converter’s output power is between 5.117 mW and 63.78 mW. This power range can sufficiently meet the demands of modern low-energy IoT devices. Moreover, fully charged and fully discharged battery scenarios were simulated to study the performance of the system. Finally, the IoT load profile was simulated to confirm the potential of the proposed energy harvesting system in self-sustainable IoT applications. Upon review of the current literature, there are limited studies demonstrating a combination of EHS with PSCs as an indoor power source for IoT applications, along with a bidirectional DC-DC buck–boost converter to manage battery charging and discharging. The evaluation of the system performance presented in this work provides important guidance for the development and optimization of new-generation PV technologies like PSCs for practical indoor applications. Full article

This study aimed to develop a novel Transdermal Energy Transmission System (TETS) device that addresses the driveline complications faced by patients with advanced heart failure (HF). Our TETS device utilizes a two-channel configuration with a very-low duty cycle and a pulsed RF power transmission technique, along with elliptically shaped flexible coil inductive coupling elements. We integrated a battery charging controller module into the TETS, enabling it to recharge an implanted Lithium-Ion (Li-Ion) battery that powers low-power-rated Circulatory Assist Devices, or left ventricular assist devices (LVADs). Benchtop measurements demonstrated that the TETS delivered energy from the implanted coils to the battery charging module, at a charging rate of up to 2900 J/h, presented an average temperature increase (ΔT) of 3 °C. We conducted in vivo measurements using four porcine models followed by histopathological analysis of the skin tissue in the implanted coils areas. The thermal profile analysis from the in vivo measurements and the calculated charging rates from the current and voltage waveforms, in porcine models, indicated that the charging rate and temperature varied for each model. The maximum energy charging rate observed was 2200 J/h, with an average ΔT of 3 °C. The exposed skin tissue histopathological analysis results showed no evidence of tissue thermal damage in the in vivo measurements. These results demonstrate the feasibility of our developed TETS device for wireless driving implanted low-power-rated LVADs and Li-Ion charging. Full article