With the advancement of lithium-ion battery technology, composite current collectors have garnered significant interest due to their role in enhancing battery energy density and safety. The mechanical performance of composite current collectors is crucial for ensuring their reliable operation. This study systematically investigates the mechanical properties of commercial polyethylene terephthalate-copper (PET-Cu) composite current collectors. The surface morphology, microstructure, and tensile fracture behavior of the PET-Cu composite were characterized using scanning electron microscopy, laser confocal microscopy, and X-ray diffraction. Stress distribution in dog-bone-shaped and long-strip-shaped samples during tensile testing was analyzed and compared through finite element simulation. The effects of sampling direction, strain rate, and specimen geometry on the tensile properties were assessed using tensile tests supported by digital image correlation technology. The dog-bone-shaped samples were found to be more effective in evaluating mechanical properties, as their transition arcs alleviate stress concentration. The mechanical properties along the machined direction proved superior to those along the transverse directions, attributed to the orientation structures of the matrix. Higher loading strain rates enhanced the overall mechanical properties of the current collector. While the geometric size of the samples had minimal impact on strength, it significantly affected elongation at fracture. The primary deformation mechanism during tensile testing was identified as dislocation slip, with surface defects such as holes acting as favorable sites for crack initiation. Considering these factors is essential when testing the tensile properties of PET-Cu composite current collectors. This research provides a theoretical foundation and reliability demonstration for the practical application of composite collectors and offers a reference for developing relevant testing standards. This study's findings are poised to advance the development of lithium-ion batteries with improved energy density and safety.

LiMn _x Fe_1-x PO₄ (LMFP) cathode materials offer higher energy density compared to LiFePO₄, making them a subject of widespread interest. However, their practical application is hindered by low power density resulting from inferior electron/Li-ion conductivities. In this study, a Mg-doped LiMn_0.5Fe_0.5PO₄ cathode is designed and synthesized. This cathode comprises secondary spherical particles self-assembled from nanoscale primary particles, with each nanoparticle uniformly coated by a carbon layer. The introduction of Mg-ions enhances Li-ion transfer efficiency by increasing the gap of octahedral LiO₆. At the same time, the carbon coating layer improves electronic conductivity by establishing a complete conductive network within the secondary particles. Moreover, the hierarchical structure shortens the migration path of Li-ions and prevents nanoparticle aggregation during long cycling processes. Consequently, the LMFP/C-1Mg cathode exhibits a reversible specific discharge capacity of 151.8 and 113 mAh/g at 0.1C and 5C, respectively. After 1000 cycles at 1C, the capacity retention increases from 90.6% to 96.4% compared to unmodified cathodes.

Bismuth has emerged as a promising anode material for sodium-ion batteries, attracting attention due to its superior ion kinetics and extended cycle life. Bismuth-based materials exhibit significant potential for enhancing energy density and charge-discharge efficiency. However, their application faces challenges due to volume expansion and the stability of the solid electrolyte interphase. These issues necessitate the development of improvements in electrical conductivity and structural stability through nanostructure design, interface engineering, and carbon coating techniques. In this study, we synthesized carbon-coated bismuth nanomaterial using a one-step carbonization method, employing a metal–organic framework of bismuth as the precursor. The bismuth particles were securely anchored to the graphene surface via C－O－Bi interfacial interactions, displaying exceptional capacity retention and stable cycling performance at high current densities. The sodium-ion storage process, dominated by pseudocapacitance, facilitates the formation of a stable solid electrolyte interphase film and enhances ion diffusion, thus improving the cycle stability and charge-discharge efficiency of the battery. The robust chemical bonds at the bismuth-graphene interfaces help maintain the structural integrity of the metal particles, buffer against volume expansion, and expedite electron diffusion, thereby boosting the electrochemical activity of the material. These findings not only provide an effective method for enhancing anode materials for batteries but also offer a new perspective for the understanding and optimization of anode materials, with significant implications for the design and development of high-performance sodium-ion battery anodes.

To enhance the stability and thermophysical properties of composite phase change materials (CPCM), sodium oleate (SOA) was employed to modify CuO nanoparticles, integrating them with n-octadecane to formulate PCMs at varying modified nanoparticle (M-CuO) concentrations. The experimental outcomes indicated a significant increase in the thermal conductivity of CPCM containing 3.0% M-CuO—up to 282.9% compared to pure n-octadecane. Additionally, the melting enthalpy decreased by as much as 6.3% with an M-CuO content of 2.0%. To further enhance the dispersion stability of the nanoparticles, sodium oleate was incorporated as a surfactant, resulting in a thermal conductivity increment of 10.4% for the CPCM compared to those without the surfactant. Molecular dynamics modeling of M-CuO/n-octadecane CPCM revealed that the thermal conductivity was enhanced by 8.6%, 10.4%, and 11.2% at nanoparticle distances of 20 Å, 30 Å, and 40 Å, respectively. Moreover, the interaction energies between M-CuO nanoparticles were reduced by 22.9, 16.3, and 20.0 kcal/mol, respectively, indicating a reduction in interaction energy and an enhancement in their stability. This study provides critical theoretical insights into the thermophysical property enhancement and optimization of CPCM, uncovering the fundamental microscopic mechanisms involved.

The separator is a crucial structural component of lithium-ion batteries, responsible for preventing direct contact between the positive and negative electrodes, absorbing and immobilizing electrolyte, and facilitating ion transfer. Commercial separators are currently challenged by issues such as thermal shrinkage at high temperatures, which compromises the long-term safety of the battery. This paper begins with an overview of the requirements for lithium-ion battery separators, including pore structure, electrolyte wettability, and stability-structural, thermal, chemical, and electrochemical-as well as separator-electrolyte interactions. It then reviews recent literature on high-temperature-resistant polymer separators, highlighting research advancements. The focus is on the analysis of strategies for high-heat-resistant polymer-based separators, flame-retardant additive-coated separators, and polymer-substrate composites. The paper discusses the mechanism behind the enhancements provided by flame-retardant multifunctional composite separators and explores strategies for inhibiting lithium dendrite formation through physical barriers, lithium deposition homogenization, and modulation of lithium-ion migration fluxes. Comprehensive analysis indicates that reducing the thickness of polyolefin separators, while integrating high-performance thin coatings, doping with solid electrolytes, and developing high-heat-resistant polymer-based separators, can achieve high ionic conductivity and ensure enhanced safety.

Compared with commercial lithium-ion batteries, sodium-ion batteries (SIBs) offer advantages such as low cost, abundant resources, good rate performance, excellent low-temperature performance, and high safety, garnering significant interest from the research community. Unlike hard carbon materials, soft carbon materials have a higher carbon content, lower cost, and greater commercial potential. However, these materials tend to graphitize during high-temperature carbonization, reducing the layer spacing, which adversely affects sodium-ion storage. This study reviews the recent advancements in the application of soft carbon materials to the negative electrodes of sodium ions. First, it summarizes the basic structure and sodium storage mechanisms of soft carbon materials. Building on this foundation, this study outlines an optimization strategy for the structural modification of soft carbon materials, focusing on four areas: porous structure modulation, heteroatom doping, composite control, and cross-linked structure construction. In porous structure modulation, techniques such as template carbonization, precursor structure formation, and physical/chemical activation methods are introduced. In heteroatom doping, the paper explores the modification effects and methods involved in nitrogen, phosphorus, sulfur atoms, and polyatomic doping. Composite control is achieved through techniques such as direct carbonization, thermal decomposition, and NH₃ treatment methods. The construction of cross-linked structures is examined through oxidation treatment and the introduction of chemical cross-linking agents, summarizing the latest research on soft carbon material modifications. The study concludes by analyzing the advantages and disadvantages of each structural optimization strategy and speculating on future directions for the development of more efficient soft carbon negative electrode materials.

The energy density of traditional lithium-ion batteries is increasingly unable to meet the demand for higher energy densities. Developing new high-energy-density secondary batteries is one way to address this challenge. Rechargeable Li/Na-Cl₂ batteries, derived from commercial primary lithium thionyl chloride batteries, have garnered significant attention due to their high energy density, positioning them as strong contenders to replace traditional lithium-ion batteries. This review examines the recent literature on rechargeable Li/Na-Cl₂ batteries, focusing on the design principles of materials and the assessment and prediction of electrochemical performance. For cathode carriers, we systematically discuss the impact of carbon materials, conjugated framework polymers, and other cathode designs on the first discharge capacity, reversible capacity, rate performance, and operational temperature of these batteries. In terms of electrolytes, we analyze solution strategies concerning the reaction mechanism, intermediate-phase products, and corrosion. Additionally, we briefly introduce new alloy anodes that are suitable for rechargeable Li/Na-Cl₂ batteries. These batteries demonstrate promising performance in the realm of new secondary batteries, thanks to the rational design of cathode carriers and electrolyte system optimization, achieving a cycle life of up to 500 cycles, particularly under extreme operating conditions (operating at -80 ℃ with a current density of 16 A/g). However, challenges such as the slow conversion kinetics of chlorine species, low utilization rate of active chlorine species, and corrosion by chlorine species at the anode remain, posing significant barriers to further improvements.

Anode materials are pivotal in sodium-ion batteries' cycle stability and energy density, constituting a fundamental component. Graphite, a widely utilized material in lithium-ion batteries, faces challenges in sodium-ion batteries due to the substantial Na+ radius and complexities in embedding within the graphite interlayer. This leads to diminished sodium storage capacity in both ether electrolytes. However, through oxidation, graphite can be transformed, expanding the spacing of graphite layers and enhancing the sodium storage sites. This process substantially improves the sodium storage capacity, giving rise to graphite oxide materials that have garnered considerable attention. This study reviews the advancements in graphite-based anode materials for sodium-ion batteries, mainly focusing on reduced graphite oxide materials. It discusses the preparation process of graphene oxide, the impact of reduction pathways on sodium storage performance, the sodium storage mechanism of reduced graphene oxide, and the influence of various functional groups on sodium ion mass transfer. Furthermore, it delves into the research progress of heteroatom-doped reduced graphene oxide as sodium-ion battery anode materials, emphasizing the physicochemical and electrochemical properties of N, S, and B-doped reduced graphene oxide. Comprehensive analysis indicates that the practical application of graphite-based anode materials in sodium-ion batteries is poised for realization by preparing reduced graphene oxide and heteroatom doping.

Flow batteries are indispensable technologies for large-scale energy storage, owing to their inherent safety and exceptionally long lifespan. In all-vanadium redox flow batteries (VRFBs), the electrode material is a crucial component, as its interface characteristics with the electrolyte substantially influence battery performance. Surface modification methods applied to the electrode facilitate enhancements in electrochemical activity, particularly under high current density conditions. Currently, electrode surface heteroatom doping technology is a focal point of research. This study summarizes the mechanisms and research progress of heteroatom doping in graphite felt (GF), specifically emphasizing two doping strategies: in-situ doping within the carbon framework and utilizing heteroatom catalysts on the electrode surface. This study also comprehensively summarizes doping types and performance differences associated with these two strategies. It explains the principles of in-situ doping in electrode materials based on the electronegativity and atomic size of heteroatoms, along with discussing how heteroatoms affect the electronic structure of carbon fibers. Additionally, it introduces the impact patterns of three carbon-based catalysts—heteroatom-doped porous carbon materials, carbon nanotubes, and graphene—on the electrochemical performance of electrode materials. The comprehensive analysis indicates that heteroatom doping on the electrode surface can increase active sites for electrode reactions, promote the migration of active ions, improve hydrophilicity, and enlarge the effective contact area between the electrode and electrolyte. Furthermore, the study suggests adopting methods such as regulating the charge distribution on the electrode surface, varying functional group types, and constructing defect sites to effectively enhance electrode materials' stability and electrochemical performance, ultimately leading to increased electrochemical activity at high current densities and higher conductivity.

With the rapid development of the new energy electric vehicle industry, a significant volume of spent lithium-ion batteries require safe disposal. The valuable metals in the cathode materials of these batteries can be recycled and reused due to their intrinsic value. Nevertheless, the potential secondary pollution affecting the environment and workers' health during the recycling process warrants attention. This study details the transformation process and mechanism of valuable metals during the three stages of pretreatment, recycling, and regeneration, with a focus on the composition and structure of spent lithium-ion batteries. The effects of impurity elements on the recycling of valuable metals and the corresponding modification methods are discussed. Initially, the impact of the electrolyte, organic binder, and collector aluminum foil on the separation of cathode materials in the pretreatment stage is elucidated. Subsequently, the reaction mechanisms of valuable metals and influencing factors are examined through methods such as pyrometallurgy, hydrometallurgy, and regeneration. The characteristics of these methods are summarized from the perspectives of recycling efficiency, energy and material consumption, and environmental impact. Lastly, this study reviews the development and prospects of the recycling techniques for valuable metals from spent lithium-ion batteries, aiming to provide a scientific basis and methodological reference for the efficient recycling and utilization of these metals.

Sodium ion batteries have broad prospects in energy storage due to their abundant raw material reserves, low and controllable costs, and production line conversion advantages. Sodium ion batteries complete charging and discharging through the mutual conversion of electrical and chemical energy, and the material properties and preparation technology of battery monomers need to meet the requirements of energy storage development. At present, developing energy storage systems that integrate high energy density, low cost, and high safety is the focus of new energy storage construction. This article starts with the energy storage mechanism of sodium ion batteries, analyzes the mechanism of the positive electrode, negative electrode, electrolyte, separator and other components of sodium ion batteries, summarizes the cutting-edge research and application progress, proposes methods to improve battery energy storage performance, aiming to optimize the technical route of sodium ion battery energy storage application and accumulate new experience in the field of electrochemical energy storage.

Aluminum silicon alloy phase change materials have good density, thermal conductivity, and thermal stability. There is great research value and application potential in energy storage and heat storage systems. This article summarizes the application and development of aluminum silicon alloy materials in the field of energy storage. The article first reviews research examples of aluminum silicon phase change materials at home and abroad, summarizes their core physical parameters, and proposes research and development directions for phase change heat storage materials and heat transfer technology based on this, including container material stability, aluminum silicon phase change physical properties, and structural optimization of phase change heat storage devices. Finally, the future application development direction of aluminum silicon alloys is summarized.

This study proposes a novel ejector–augmented adiabatic compressed air energy storage system designed to mitigate the significant pressure loss observed in conventional systems during constant-pressure operation. It employs a two-stage ejector to harness the exhaust gas after expansion, thereby recovering part of the lost pressure energy and enhancing the expander's inlet flow rate to boost the system's power generation capacity. We developed a thermodynamic model for this novel system and performed a comparative analysis with conventional systems using identical operating parameters. This study focuses on the effects that the primary fluid pressure, secondary fluid pressure, and intermediate pressure within the two-stage ejector have on system performance. Results reveal that increasing these pressures causes the full-cycle efficiency of the system to follow an approximate parabolic trend. Furthermore, the optimal operating parameters of the ejector have been identified. Under optimal working conditions, the system's full-cycle efficiency is 63.32%, indicating an improvement of 0.91% over the 62.41% efficiency achieved by the conventional throttling-down method. Based on the above, this study establishes a theoretical foundation for enhancing the ejector efficiency of compressed air energy storage systems, aiming to reduce throttling loss and improve overall performance.

Rational utilization of hydrogen energy can enhance the flexibility of optimizing integrated energy systems and effectively mitigate the impacts of source and load uncertainty on system operations. Employing hydrogen-compressed natural gas (HCNG) as fuel and incorporating it into cogeneration combined heat and power systems can significantly enhance economic efficiency and hydrogen energy utilization. This paper proposes an optimization framework for the operation of integrated energy systems incorporating HCNG, considering multiple scenarios and uncertainties. The approach begins by establishing an integrated energy system topology that utilizes HCNG as fuel. It then addresses the uncertainties of sources, loads, and scenario probabilities through a three-stage robust optimization model aimed at minimizing system operating costs. The main and subproblems are decomposed using the Column and Constraint Generation (C & CG) algorithm. The Karush-Kuhn-Tucker (KKT) conditions and the Big M method are applied to transform these into a single-layer optimization problem. Comparative analysis of system operation results and robust models demonstrates that HCNG can optimize system operations and reduce costs effectively. The proposed model adeptly handles the discrepancies between actual and predicted scenario probabilities, thus preventing extreme outcomes during system optimization.

Large-scale energy storage technology plays a crucial role in the development of renewable energy and the stability of power grids. Rail gravity energy storage (RGES) technology enables flexible load locomotive dispatch for energy storage and release. It effectively addresses the issue of significant power fluctuations in wind farms and presents significant potential for long-term, large-scale energy storage applications. This paper explores the key influencing factors of the RGES system and its integrated scheduling with a wind farm. We constructed models of the RGES system and its coupled system with the wind farm using MATLAB software. The study examines how key parameters affect the RGES system during the energy storage and release process. To minimize the wind power curtailment rate, we analyzed the operational characteristics and system configurations of the coupled system during typical days across all seasons in detail. The results indicate that the power for energy storage and release increases with higher load mass and faster upward/downhill speeds during the constant speed phase. The efficiency of energy storage and release, as well as overall system efficiency, show minimal variation with load mass but decrease with increasing speeds. When coupled with a wind farm, the RGES system can adapt the number of trucks and their speeds for optimal energy storage and release, achieving stable power outputs of 22 MW, 16 MW, 27 MW, and 29 MW during peak consumption on typical days in each season, enhancing the wind power utilization rate by an average of 17.1%.

With the increasing integration of new energy sources, the issue of frequency stability in power systems is becoming more severe. This study proposes an improved control strategy for primary frequency regulation of a flywheel energy storage–assisted wind farm. Herein, the frequency characteristics and capacity configuration of a wind-storage system are analyzed. The wind farm adopts virtual inertia control to participate in primary frequency regulation. However, due to random variations in the natural wind speed, the output power of the wind farm may cause flywheels to operate at high or low speeds for prolonged durations. In cases of abrupt changes in the wind speed, the flywheel may even exceed its speed limit. To prevent the overspeeding of the flywheel, virtual droop control is employed along with fuzzy rules to compensate for the power deficit of the wind farm in the primary frequency regulation. Simulation analysis and experimental validation under step and continuous load disturbances show that the improved control strategy exhibits smaller maximum frequency deviation and faster response speed in both disturbance scenarios.

Long-term high temperatures and temperature differences can damage battery performance and lifespan. Therefore, a novel two-phase cold plate liquid cooling system has been developed for large-scale energy storage, and its temperature control effect has been measured at an energy storage power station in Xiangtan City, Hunan Province. First, the control effect of the two-phase cold plate on battery temperature variation and temperature consistency across the entire cabin and each box during the entire charging and discharging process is examined. Subsequently, the temperature variation in the battery after charging and discharging is analyzed. The results indicate that two-phase cold plate cooling can effectively mitigate temperature increases and improve the temperature consistency of the battery, reducing the maximum temperature difference from the traditional liquid cooling system range of 4.17 ℃ to within 3 ℃ during charging and discharging. Under identical conditions, the heat dissipation of the battery during charging exceeds that during discharging. If the cooling system is not turned on during the static phase, the phenomenon of elevated battery temperatures inside the power station will persist for 80 minutes or longer.

Liquid air energy storage (LAES) has significant potential for use in multi-energy coupled integrated energy systems. Appropriately configuring energy storage capacity can enhance the low-carbon and economic operation of these systems. However, current research has yet to fully account for the combined heat and power supply characteristics of LAES. Therefore, this study proposes a configuration optimization method for a combined heat and power supply LAES-coupled integrated energy system. Based on the foundational architecture of the integrated energy system, we develop heat and power co-supply and constraint models for system components. The system's total annual cost, encompassing the initial equipment investment, operation and maintenance costs, energy purchase expenses, and penalties for solar and wind energy abandonment, serves as the objective function. Considering the constraints of system energy balance, equipment capacity, equipment output, interaction with external networks, and energy storage constraints, we establish an optimal configuration model. This model is solved using the mixed-integer linear programming method. A real-world park scenario is used to set up five different scenarios for comparative analysis of optimization results. The simulation findings demonstrate that an integrated energy system incorporating LAES heat and power co-supply can effectively meet real-time system energy demands while achieving better economic and environmental outcomes. Compared with traditional sub-supply systems, the integrated approach reduces total costs by 37.1% and carbon emissions by 71.50%. It also offers substantial benefits in terms of lowering carbon emissions and minimizing wind and solar energy waste. This study provides a theoretical basis for the effectiveness of the optimization model for a heat and power co-supply LAES-coupled system and promotes the commercial application of LAES in integrated energy systems.

Compressed air energy storage is regarded as one of the most promising technologies for physical energy storage, as the compressor's performance plays a crucial role in determining the economic viability and efficiency of the system. The efficiency of the compressor is significantly influenced by its tip-clearing flow, owing to its complex three-dimensional flow characteristics. This flow affects the structural changes within the internal flow field of the compressor, marking it as a key factor in the compressor's performance. Tip clearance flow remains a challenging and crucial topic in this field owing to its complex flow properties and significant effect on the aerodynamic design of the compressor. This study classifies and summarizes the mechanisms and research significance of blade tip clearance flow across various compressor types: shrouded and unshrouded axial compressors, as well as open/semi-open and closed centrifugal compressors. According to the flow characteristics of compressors, the research progress on blade tip clearance flow domestically and abroad is further reviewed. The key findings include: unsteady tip clearance in unshrouded axial-flow compressors, which is closely related to stall, blade noise, and vibration, underscoring the need to optimize tip design. Shrouded axial compressors have received little attention owing to the lack of experimental data and limited flow control methods. The application of control technologies in different fields could be beneficial. For centrifugal processors, future studies should investigate how variable clearance characteristics and circumferential inhomogeneity affect the flow structure and improve the adaptability of flow field variation. Future research should focus on the application and popularization of high-precision numerical simulation methods, attempts at cross-domain control technology, and the exploration of composite structures.

Under the strategic goal of "double carbon," renewable energy power generation, including solar and wind energy, has experienced steady growth. However, the existing technology faces challenges in supporting the increasing consumption of renewable energy, necessitating large-scale energy storage devices to ensure the stable operation of the power grid. Pumped thermal energy storage(PTES)technology is a promising solution, offering high efficiency, high energy storage density, and flexible on-demand construction. Compared to other large-scale energy storage technologies under development, PTES demonstrates superior research value and application prospects. This paper begins outlining the working principle of PTES and categorizes it into power storage systems based on the Brayton cycle (three types) and systems based on the Rankine cycle. A comparison and summary of the technical characteristics of these two systems are provided. While the Brayton cycle-based system faces challenges related to high heat storage temperatures, the Rankine cycle-based system effectively reduces heat storage temperatures but introduces issues with high system pressure. Subsequently, the research status of the core components of PTES is outlined, along with the influence of storage tank arrangement and energy storage medium type on system efficiency. Comprehensive analysis reveals that current heat pump power storage technology research primarily focuses on the power storage system's process design and thermodynamic optimization analysis. PTES holds promise in power storage and exhibits potential in waste heat recovery and cogeneration. Establishing a multi-energy complementary system utilizing low-grade waste heat in various production and life scenarios can enhance PTES's efficiency in electricity, heat, and cold regulation and management within the energy system. This approach is anticipated to expedite the transition of China's energy system toward greener and lower carbon emissions.

Under the background of low-carbon emission reduction policies, optimizing energy storage modes has become a core issue in the power system. From the perspective of low-carbon development, the user-side energy storage model plays an important role in the development of new energy and the balance of supply and demand in the power system. Firstly, the paper discusses the commercial value of user-side energy storage in terms of peak valley price arbitrage, demand electricity fee management, and demand response. Secondly, combining examples, the paper analyzes the advantages and disadvantages of leasing mode, sharing mode, virtual power plant mode, and community energy storage mode. Finally, the paper proposes that the user-side energy storage model can develop towards energy storage service optimization, battery sharing, multi-point aggregation, and other directions, providing reference for the sustainable development of the electricity market.

By combining phase change heat storage air source heat pumps with solar heating, the heating capacity of the system can be improved while fully utilizing solar energy resources. To ensure heating efficiency and provide high-quality energy resources, research is conducted on the optimization of phase change heat storage air source heat pump systems and solar complementary heating systems. Based on the thermal conversion mode and thermal energy conversion efficiency of phase change heat storage air source heat pumps, analyze the thermal effect of the heating system, and on this basis, conduct in-depth research on the heating performance of solar heating systems. Based on the advantages of the above two applications, specific heating system optimization design schemes are defined from multiple aspects, including optimizing phase change material configuration, improving solar collector efficiency, optimizing system control strategies, and improving heat energy transmission and utilization.

Currently, environmental protection issues under energy consumption and development are the core of energy research in China. Flywheel energy storage technology is simple and direct, with the advantages of high power and high energy storage density. There are basically no restrictions on charging and discharging times and environmental pollution, making it a relatively advanced energy storage technology. The article provides an overview of the core structure of flywheel energy storage systems, including the flywheel rotor structure and flywheel bearing structure; At the same time, the current advanced computer processing control technologies for flywheel energy storage motor control were listed, including flywheel energy storage control technology under fuzzy logic, flywheel energy storage control technology based on BP neural network, and energy storage control technology under particle swarm optimization algorithm.

Lithium-ion batteries produce large amounts of flammable gases during thermal runaway, which is the main risk of explosion in energy storage systems(ESS). In order to investigate the generation and diffusion law of combustible gas in thermal runaway of ESS,we firstly tested the gas production composition of a lithium iron phosphate battery under different thermal runaway triggering conditions through experiments. Based on the experimental results, a simulation model of gas generation and diffusion in thermal runaway process of prefabricated cabin energy storage system was established, and the combustible gas diffusion law after triggering thermal runaway in different positions of battery cells was analyzed. The results show that H₂ accounts for about 30% of the released gases and is not affected by air components, making it more suitable for use as a warning gas in the early stages of thermal runaway in batteries. It is found that within 3 s of the opening of the explosion-proof valve of the electric cell, H₂ is mainly concentrated in the area of the battery module. With the air-cooling cycle, it spreads to the external inter-area position of the battery module, and will spread to the whole storage battery compartment within 120 s. Based on this, the optimal gas sensor and duct arrangement scheme for this energy storage module is given. The results of this paper can provide a reference for the layout of combustible gas monitoring points and the design of emission paths in energy storage systems..

Lithium battery energy storage plays a crucial role in harnessing new energy for power generation and achieving the national "dual-carbon" objectives. This technology is indispensable for ground-based, industrial, and commercial energy-storage applications. A critical aspect of its widespread adoption is ensuring the safety of lithium batteries against thermal runaway and fire hazards. To this end, early detection of gases typically released during the thermal runaway phase of a lithium battery is essential for fire warning in energy storage. However, accurately identifying these gases poses challenges in environments with mixed gases owing to cross-interference from data collected by various gas sensors. Such interferences often lead to inaccurate detections, delayed or false alarms, and potential fire hazards. To address these issues, we propose a decoupling method designed to enhance the precision of detecting typical gases, namely H₂ and CO concentrations, in mixed gas environments. This method involves establishing response models for each sensor in different single-gas environments and understanding the cross-coupling relationships between different gases and sensors. By deriving the relationship between the sensor signals and the gas components and concentrations in mixed-gas scenarios, we can establish an equation system. This system is crucial for obtaining precise concentration data for each gas, thus facilitating the decoupling of sensor data. In experimental testing with a mixed gas scenario of H₂ and CO, which was built to simulate the early gas environment of lithium battery thermal runaway across different chemical systems and different states of charge. The results demonstrated a detection error of less than 50 mL/m³ within the concentration range of 0—1000 mL/m³. The maximum improvement in detection accuracy reached 15%, validating the effectiveness of the proposed method outlined in this study.

Given the uncertainty surrounding preretirement battery conditions, this study aims to advance the data-driven approach for accurately estimating retired lithium batteries' state of health (SOH). To achieve this, an enhanced SOH estimation method based on the Gaussian process regression (GPR) model is proposed. Initially, cyclic charge and discharge data from retired lithium batteries are gathered, and statistical health characteristics are derived to depict the aging properties. Methods such as capacity increment analysis (ICA) and electrochemical impedance spectroscopy (EIS) are employed to consider temperature effects. The Pearson correlation coefficient was used to assess the correlation between selected statistical features and health characteristics, identifying those highly correlated with SOH to eliminate the feature redundancy. Subsequently, acknowledging the limitations of individual kernel functions and conventional hyperparameter optimization techniques, a hybrid approach combining linear and diagonal square exponential kernel functions is introduced to better accommodate the diverse nature of battery SOH estimation tasks. The whale optimization algorithm (WOA) is then applied to optimize the hyperparameters of the estimation model, ensuring optimal fitting. This leads to the establishment of an improved GPR estimation model to enhance estimation accuracy. Finally, the effectiveness of the proposed method was validated using four different cells with varied initial health conditions from the NASA battery dataset. Results demonstrate the method's capability to provide accurate SOH estimation, with a mean absolute error below 1.75% and a root mean square error below 2.42%.

This study integrates the electrochemical thermal coupling model with the reverse disassembly method to facilitate easier access for end-users to electrochemical parameter data about the battery cell's interior. It employs finite element simulation analysis and electrochemical parameter optimization experiments to validate the accuracy of the obtained parameters. Furthermore, it examines the impact of the Bruggman coefficient, reaction rate constant, and solid-phase diffusion coefficient on the charging and discharging performance and the temperature of power batteries. The findings reveal that the reverse disassembly method effectively captures the dynamic and thermodynamic battery parameters, with an error margin of approximately 3% for voltage and temperature in standard lithium batteries. Notably, the Bruggeman coefficient influences voltage, particularly in the middle and later stages of discharge, wherein an increase in its value amplifies polarization. Moreover, as the Bruggeman coefficient rises, battery temperature demonstrates a decreasing trend. The reaction rate constant affects voltage across the entire discharge range, inversely correlating with temperature; higher reaction rate constants correspond to reduced polarization. Similarly, the solid-phase diffusion coefficient influences voltage within the low state-of-charge (SOC) range, with higher values diminishing polarization.

In hydrogen fuel cell vehicles, the Fuel Cell DC-DC converter (FDC) is a key interface between the hydrogen fuel cell stack(hydrogen stack) and the inverter, and the stability of its output DC bus voltage is a key link to ensure the normal operation of loads such as the motor. So, a new type of sliding mode predictive control is proposes in this article. Firstly, the topology of FDC is improved and a predictive model based on sliding mode surface is established. Then, a sliding mode surface value function is designed to improve the tracking accuracy of FDC; On this basis, in order to achieve online intelligent monitoring of the hydrogen reactor, the variable step linear interpolation lookup table method is further adopted to accurately estimate the impedance of the hydrogen reactor online. Firstly, the FDC is digitally controlled to generate small sinusoidal harmonics with variable frequency, and the multi frequency impedance value of the hydrogen reactor is estimated based on the input voltage and current sampling of the FDC; Then, the variable step linear interpolation lookup table method is used to compare the estimated impedance value with the design standard value, evaluate the current state of the hydrogen reactor, and achieve online intelligent monitoring of the hydrogen reactor. Finally, simulation and experimental verification will be conducted. The results show: ①When the experimental reference current is set to 100 A, The system current overshoot and response time under traditional PI control are 20 A and 15ms, respectively. In contrast, the system current overshoot and response time under sliding mode predictive control are 1.5 A and 2.5 ms, respectively; ②The tracking accuracy of FDC for self generated harmonics can be controlled within 2%; ③The variable step linear interpolation lookup algorithm can achieve accurate estimation of fuel cell impedance. Verify the effectiveness of the algorithm.

The thermal simulation analysis of a liquid-cooled energy storage battery pack was conducted at room temperature, and the results were compared and analyzed against thermal test results obtained under the same working conditions. The simulation parameters were adjusted to match the technological level, ensuring the error between the simulated and experimental values at measurement points remained within 1 ℃. Using these parameters, thermal simulations of the battery pack were performed under extreme environmental conditions of high and low temperatures. In the high-temperature scenario, the battery cells reached their final discharge state, while in the low-temperature scenario, they remained in a static state. The calculations indicate that the average cell temperature under high-temperature conditions was 39.2 ℃, with the highest temperature recorded at 41.2 ℃. Conversely, the average cell temperature under low-temperature conditions was 7.8 ℃, with the lowest temperature at 3.7 ℃. These findings indicate that the liquid-cooled battery pack can maintain cell temperatures within the normal operating range, even in extreme environments. The thermal simulation method outlined in this study offers a comprehensive approach to analyzing the battery pack's thermal state under extreme conditions, providing an avenue to assess the thermal performance of the energy storage system when experimental costs are prohibitive, or conditions cannot be replicated.

Ternary lithium-ion cells, recognized for their superior electrochemical properties, are extensively utilized in the energy storage sector. This research uses commercial 18650 lithium nickel-cobalt-manganese (NCM)/graphite cells as experimental samples to explore the effects of float-charging at 4.2, 4.4, and 4.6 V. We conducted a series of analyses including capacity tests, incremental capacity analysis, and impedance tests, complemented by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) of electrode materials from disassembled cells. The influence of float-charging on thermal safety of NCM cells was studied through the accelerating rate calorimeter (ARC) test. Our findings indicate that higher float-charging voltages accelerate cell aging, with an average capacity loss rate of 1.166%/day at 4.6 V. Float-charging at elevated voltages intensifies the interface reactions between the electrolyte and electrode, resulting in a thicker solid electrolyte interface (SEI) film and a substantial increase in impedance. Furthermore, it induces corrosion of the positive collector, leading to aluminum precipitation and deposition at the negative electrode, which further accelerates the capacity attenuation. The onset temperature of self-heating (T_onset) of the cells is reduced after float-charging, indicating a decrease in thermal safety. Through float charging process analysis, failure material characterization, and thermal runaway experiments, this study provides theoretical insights and technical guidance on the impacts of float-charging on the electronic and thermal safety performance of lithium-ion cells.

Lithium ion battery energy storage plays an extremely important role in the fields of clean energy use, electric vehicles, mobile devices, and renewable energy storage. Once a malfunction occurs, it is easy to cause a series of problems, so conducting fault analysis to understand its actual health status is of great significance. This article provides an overview of lithium battery fault analysis techniques under deep learning mechanisms. Based on a deep understanding of deep learning diagnostic theories such as multi-layer perception and recurrent neural networks, this paper elaborates on the evaluation framework and process of the latest lithium battery fault diagnosis model (LSTM). Through practical applications, it can be determined that the deep learning based lithium battery fault analysis model has advantages such as high recyclability and good accuracy, and is worthy of further research and exploration.

To enhance the operational economy of heating systems in winter sports venues after the Olympics, a physical-mathematical model of the thermal storage device from the venue's heating system's was constructed. Numerical simulation methods were employed to study the thermal storage device. The simulated results of temperature stratification within the thermal storage device were compared and analyzed against field-measured data, validating the accuracy of the model. The structure and temperature scheme of the thermal storage device were optimized by leveraging the local peak-valley electricity price system, aiming to optimize the operating costs of electrode boilers, with constraints the cavitation margin of the heat release pump and the total power of the electrode boiler. The influence of the thermal storage device's manifold distributor structure and thermal storage media temperature on the energy conservation and the economic viability of the heating system were investigated. Results indicate that the designed diffuser-type manifold distributor structure outperforms the manifold distributor structure in the Yanqing Winter Olympics Village's thermal storage device, as it exhibits superior temperature stratification within the thermal storage device during operation. This results in lower mixing of the thermal storage media at different temperatures within the device, which, in turn, lead to higher outlet temperatures and further improvement of the room comfort. The heating efficiency improved from 82.02% to 85.98% after optimization. During the period from winter solstice to New Year's day, the optimal temperature of the thermal storage media was 95 ℃, leading to a reduction in the operational costs of the electrode boiler heating system by up to 14.13%. This work highlights the value of engineering applications and provides guidance for post-Olympic venue operations and operational improvements in thermal storage heating systems.

In line with the "carbon peak, carbon neutral" initiative, the significance of hydrogen energy is increasingly recognized. Currently, hydrogen energy storage, based on the "electric-hydrogen-electric" process, is primarily in the demonstration application phase, with energy storage cost being a critical factor for its competitiveness. However, targeted research on the levelized cost of large-scale hydrogen energy storage (LCOES) is lacking. This study addresses this gap by establishing an LCOES model for hydrogen energy storage power and conducting quantitative analysis on a 25 MW scale hydrogen energy storage power station system. Subsequently, LCOES levels are projected for future scenarios. The findings reveal that the LCOES of the hydrogen energy storage system is 4.758 CNY/kWh. Capital expenditures are primarily attributed to the hydrogen production system (44.66%), while operational expenditures are dominated by hydrogen production costs (42.99%). Electricity prices notably influence hydrogen energy storage costs, with every 0.1 CNY/kWh decrease resulting in an 8.18% reduction in LCOES. Although enhancing power generation efficiency is challenging, it substantially impacts the economics of hydrogen energy storage, with every 10% increase leading to an 11.88% to 12.50% reduction in LCOES. A 10% decrease in the prices of hydrogen production and power generation system equipment correlates with a 6.06% decrease in LCOES. Energy storage duration markedly affects LCOES, particularly with shorter durations. Within the 4 to 8 h range, each additional hour of energy storage could decrease LCOES by an average of 0.394 CNY/kWh. As hydrogen production and fuel cell equipment prices decline and efficiency improves, hydrogen energy storage is anticipated to emerge as a competitive technical solution for long-term and extended-duration energy storage applications.

Energy storage technology provides an efficient way to relieve strain on power grids caused by the integration of large-scale renewable energy sources. It also addresses the challenges posed by the intermittent and unpredictable nature of power generation from wind and solar energies. This study examines the most efficient way to store energy in the photovoltaic power stations of the Beipanjiang River basin, considering their specific traits. To enhance the operation of photovoltaic systems in this region, a combination of electrochemical and hydrogen energy storage is utilized. The primary goal is to minimize the net present value cost of the energy storage system, with the capacity of the energy storage system and the maximum power for charging and discharging acting as constraints. The economic advantages of various energy storage devices are analyzed and optimized. Utilizing HOMER Pro software for operational analysis, optimal energy storage capacity configuration is determined. The economy is then divided into power generation side, power grid side, and financial leasing mode under multiple application scenarios based on the current price standards in Guizhou Province. This segmentation helps obtain economic benefits and revenue models under each application mode. This approach provides a practical solution for energy storage configurations in photovoltaic power stations in the region, offering significant value.

The advent of new energy storage technologies has identified them as key components for shaping innovative power systems, which are essential in achieving carbon peak and carbon neutrality goals. This paper leverages patent data to explore the developmental trends and research status of emerging energy storage technologies in China, including electrochemical, compressed air, and hydrogen energy storage. It primarily examines subfields using the LDA topic model and offers detailed analyses of patent durations, regional patterns in patent applications, applicant units, and collaboration relationships. Moreover, it assesses the global status and trends of these technologies. The findings reveal a rapid growth trend in the development and application of emerging energy storage technologies, with China emerging as a global leader. In the realm of Chinese patents, lithium-ion batteries and supercapacitors demonstrate significant growth, alongside other flourishing technologies such as compressed air and hydrogen energy storage, liquid metal batteries, and aqueous batteries. Patent applications are predominantly filed in economically developed regions like Guangdong, Jiangsu, Beijing, and Zhejiang. While regional focuses vary, the majority of applications originate from universities and private enterprises specializing in new energy. Based on these insights, it is recommended that future advancements in emerging energy storage technologies be led by major research entities to enhance coordinated development in less developed areas. Strengthening partnerships between universities and private enterprises is also vital for driving the integrated progress of these technologies across academia, industry, and research sectors.

As China advances its "Carbon peak and carbon neutrality" strategy, there is heightened emphasis on innovating advanced energy storage technologies. Driven by national policy and industrial demand, the rapid development of these technologies has precipitated a significant shortage of both basic and high-level professional talents needed for their large-scale advancement. In response, the Ministry of Education launched a new major in Energy Storage Science and Engineering in 2020 to meet the growing need for adept professionals in this field. This new discipline integrates multiple fields including Power Engineering and Engineering Thermophysics, Chemical Engineering, Electrical Engineering, Materials Science and Engineering, and Management Science and Engineering, positioning it as a quintessential interdisciplinary subject with a complex knowledge structure. Addressing the challenge of training high-level talents, Tianjin University has leveraged its extensive experience in reforming engineering education. Utilizing the National Industry-Education Platform for Energy Storage, the university has pioneered the "1+N+X" model of industry-education integration and collaborative education. This model includes initiatives such as reforming the joint training mode of universities and enterprises, establishing collaborative internship and practice bases, and constructing enterprise tutor teams. Furthermore, the university conducts various training activities, including postgraduate training, undergraduate internships, project-based practice teaching, and advanced training in Energy Storage Science and Engineering. These initiatives have yielded significant outcomes, contributing effectively to the cultivation of high-level talents in the energy storage sector.