This bimonthly review paper highlights 100 recent published papers on lithium batteries. We searched the Web of Science and found 3128 papers online from Feb. 1, 2022 to Mar. 31, 2022. 100 of them were selected to be highlighted. High-nickel ternary layered oxides, LiNiO₂,LiCoO₂ and Li-rich oxides as cathode materials are still under extensive investigations for surface coating, preparation of precursors and structural evolution with cycling. The methods for improving the cycling performances of Si-based anode focus on surface coating and 3D structure design of the composite Si/C and Si/Sn anodes. Metallic lithium anode is extensively studied and 3D structure design and surface reconstruction are common methods. Solid state electrolyte including oxide, sulfide and composite materials have been widely studied. Meanwhile, large efforts are still devoted to liquid electrolytes for the optimizing the electrolyte for Li or graphite anode, and the high-voltage cathode materials. For solid-state batteries, there are a few papers related to the design of composite cathode, bi-layer electrolyte, and inhibition of Li dendrite and side reactions. Other relevant works are also presented to cathode design of liquid lithium sulfur battery. The characterization techniques are focused on lithium diffusion, SEI formation, electrochemical and chemical stability of the sulfide electrolytes. Theoretical simulations are directed to the doping of ternary oxide cathode materials, physical and chemical properties of liquid electrolyte and screening of solid electrolytes. The interfaces of liquid electrolyte/electrodes and solid state electrolyte/Li are also drawn large attentions.

Lithium titanate (LTO) batteries are well-known for their long cycle life, good rate performance, and thermal safety. However, few studies reported the effects of electric and thermal abuse on the electrochemical performance and thermal safety of LTO batteries. In this study, the electrical and thermal safety properties, as well as the microstructure of electrode materials of certain types of commercial cylindrical 18650 LTO batteries were studied under a series of slight over-discharging conditions at various current rates (0.5 C, 1 C, 2 C, 5 C, and 1 C 100 cycles) with the aid of an electrochemical workstation and accelerating rate calorimeter. Moreover, we then adopted a "top-down" strategy to disassemble the LTO batteries to obtain their anode and cathode materials. We also examined the structure of such electrode materials via an X-ray diffractometer and scanning electron microscope from a microscopic point of view. Related results have illustrated that (1) the internal resistances of LTO batteries changed little after the first cycle of over-discharging with current rates of no more than 5 C. While manifold cycles of over-discharging dramatically accelerated the aging of LTO batteries, reflected by the quick drop in their energy retention rate and the rise in internal resistance. However, the thermal safety character of the batteries with manifold cycles of over-discharging has shown no significant change. (2) The thermal safety of LTO batteries can be significantly reduced after over-discharging treatment at a large current rate (5 C), with the onset temperature of self-heating (T₁) decreasing and the maximum temperature (T₃) in the thermal runaway process rising simultaneously. The partial cracking and pulverizing of LTO particles and the uneven SEI generated on the anode material are the leading causes for the deterioration of the thermal safety character of LTO batteries under over-discharging conditions. This research has illustrated the potential risk of over-discharging on the electrochemical performance and thermal safety of LTO batteries. We hope this work could bring attention to the safe application of LTO batteries.

The occurrence of carbon deposition on the anode of a solid oxide fuel cell (SOFC) is the bottleneck restricting its efficiency and stabilization. This paper reviews the research progress on the carbon deposition of SOFC in the experimental field both at home and abroad and points out the significance of determining a mathematical model of the carbon deposition rate. The SOFC carbon deposition experimental system is constructed composed of a gas pipeline, gas flow controller, open vacuum atmosphere, tubular electric heating furnace, and other instruments and equipment. The preparation of the sheet anode material for the experiment and the detailed steps of the carbon deposition experiment are introduced. We obtained the following based on the experimental results of the carbon deposition characteristics of the CO on Ni/YSZ anode: (1) the effect of CO/CO₂ volume fraction on carbon deposition characteristics of CO disproportionation reaction; (2) effects of temperature on carbon deposition characteristics of CO disproportionation reaction; (3) effects of CH₄ scission reaction and CO disproportionation on carbon deposition characteristics. Finally, based on the chemical reaction kinetics, the mathematical calculation model of the carbon deposition rate of CO disproportionation reaction at various temperatures is deduced and verified by the experimental results. This study is helpful to explore the mechanism of carbon deposition in an SOFC and provides a basis for the optimal control of SOFC operating parameters with natural gas as fuel.

A none-quilibrium molecular dynamics method was used to study the influence of defects on the thermal conductivity of single-layer graphene (SLG). The SLG model for different defect types includes single-vacancy and double-vacancy (DV) defects and establishes a defect concentration of 0.1%—0.5%. The model was verified using phonon density of states. Based on this model, defect concentration and temperature were adopted as variable conditions. Model thermal conductivity was simulated during the heat transfer process. The thermal conductivity of SLG for different defect types was compared, the results show that, at a temperature of 300 K, with increased defect concentration, the thermal conductivity of SLG decreases sharply. This trend of decreasing conductivity lessens when the defect ratio reaches 0.2%. When the DV defect concentration in SLG is 0.3%, thermal conductivity is 144.5 W/(m·K) for a temperature rise from 300 K to 700 K. The corresponding reduction in thermal conductivity is 26.4% of that at 300 K. Therefore, the thermal conductivity of SLG modulated by DV defects is less affected by temperature. The study provides a theoretical reference for the thermal management of real-world applications of SLG-based devices at micro- and nano-scales.

Thermochemical heat storage has the advantages of high energy storage density, good cycling performance, long storage time and small heat loss, and has a broad prospect in improving energy efficiency and reducing carbon emissions. Before the application of large-scale system process, it is of great significance to judge the applicability of heat storage materials by means of experimental detection, dynamic calculation and numerical simulation. In this paper, taking silica gel as an example, nuclear magnetic resonance instrument was used to detect the change of the internal water binding form and its content before and after heat storage, and then the thermochemical reaction equation in the process of silica gel heat storage was calculated and determined. According to the experimental data of thermogravimetric analyzer (TGA), the non-isothermal kinetic calculation of the thermal decomposition reaction of silica gel was carried out, and the activation energy of the reaction was obtained to be 66.75 kJ·mol^-1. With the advance of the reaction process, the activation energy of silica gel dehydration reaction decreased as a whole, and the most probable mechanism function was the three-dimensional diffusion model. The three-dimensional diffusion rate of water vapor at the gas-solid interface is a key step affecting the total reaction rate. According to differential scanning calorimeter (DSC) experiment, the heat absorption rate of silica gel reaches its peak at about 100 ℃, about 0.87 kW·kg^-1, and the heat storage density is 1030.89 kJ·kg^-1. The calculated kinetic parameters were used to simulate the heat storage process in the reactor in Fluent, and Pearson correlation coefficient was used as the evaluation index of the correlation between the experimental and numerical simulation results. The results show that the numerical simulation predicted value is in good agreement with the experimental value.

A 1.6 Ah 18650 lithium-ion nominal capacity battery with a prelithiation process was developed to determine the capacity fading factors of lithium-ion batteries after high-temperature storage. Comparative analysis of the capacity loss, capacity recovery, dQ/dV, EIS, SEM, XRD, EDS, ICP, and thermal analysis of the battery storage under RT and 70 ℃ after five months at 100% SOC, respectively. The results demonstrate that the battery's discharge capacity at 70 ℃ is only 79.14% of its capacity at 25 ℃, and the reversible capacity loss accounts for 52.8%. The irreversible capacity loss is primarily due to the severe imbalance between the cathode and anode. The nonprelithium battery is subjected to anode fading, whereas the prelithium battery undergoes cathode fading due to the excessive lithium in the anode. Furthermore, the internal resistance of the battery storage under 70 ℃ is greater than that under 25 ℃, particularly when the anode quantity increases. There is significantly more "dead lithium" on the surface of the anode for the battery storage under 70 ℃ and more oxygen content was observed, meaning more side reactions on the surface. Moreover, high-temperature storage did not affect the structure of the electrode materials.

Electrolysis of water by hydrogen evolution reaction (HER) shows a broader potential for hydrogen production than traditional methods. However, the kinetic process is slow, and this constitutes a key bottleneck. Development of an efficient, low-cost, electrocatalyst is crucial to progressing HER. In this study, an HER electrode was prepared using nickel nanoparticles supported by biomass-derived activated carbon. Biomass canvas formed the carrier and a variant of Schweitzer's reagent the nickel source. The effects of both phosphating and of reagent concentration on HER performance were studied. A range of analytical techniques (SEM, EDS, XRD, and electrochemical measurement) was used to characterize the morphology, phase composition, and HER performance of the catalysts. Results indicate that there is a critical value for nickel nanoparticle concentration on the carbon cloth, and also that phosphating modification can reduce the overpotential of hydrogen evolution and improve catalyst durability. The modified electrode (1 mol/L NiP@C) shows effective HER performance in 1 mol/L potassium hydroxide solution, exhibiting very low overpotential and Tafel slope at a current density of 10 mA/cm². Additionally, the overpotential after IR compensation is only 23.5 mV under high current density (100 mA/cm²). After a 10-hour chronopotentiometric test at variable current densities, the potential retention rate was about 92%, demonstrating a highly durable performance.

Iron-Chromium flow battery (ICFB) was the earliest flow battery. Because of the great advantages of low cost and wide temperature range, ICFB was considered to be one of the most promising technologies for large-scale energy storage, which will effectively solve the problems of connecting renewable energy to the grid, and help achieve carbon peak and carbon neutrality. Firstly, the main advantages of ICFB for large-scale energy storage are discussed, and the development and application of ICFB at home and abroad are introduced as well. Then, the technical bottlenecks of ICFB in the application of energy Storage were summarized and analyzed, including low energy efficiency due to poor electrochemical activity of chromium ion in the electrolyte, and poor stability due to the hydrogen evolution of the negative electrode at the end of charge process. Furthermore, the current research progress was described from four aspects, including electrolyte, electrode, membrane, and structure of flow battery. Finally, contrapose the limitation of ICFB, breakthroughs and innovations for the future ICFB are proposed to provide reference and basis for the development of ICFB, including improving key materials, optimizing design structure, and reducing battery cost.

All-solid-state lithium battery has become one of the most promising candidates to replace the traditional lithium battery utilizing liquid organic electrolytes due to its high safety and high energy density. The solid electrolyte is the crucial component of all-solid-state lithium battery, and sulfide electrolytes are attractive among solid electrolytes due to their high ionic conductivities and good mechanical ductility. Li₃PS₄ solid electrolyte with high ionic conductivity, wide electrochemical windows and low cost has been attracted significant attention in recent years. However, its poor air/moisture stability and low compatibility towards cathode/anode materials limit its large-scale application in high-performance all-solid-state lithium batteries. In this paper, the structural mechanism and preparation route of Li₃PS₄ solid electrolyte were reviewed by discussing the recent literature on Li₃PS₄ solid electrolyte. Then, the strategies applied to enhance the ionic conductivity, improve the chemical/electrochemical stability, and strengthen the mechanical properties of Li₃PS₄ are summarized, and the applications of Li₃PS₄ electrolytes in solid-state batteries combined with different kinds of electrode materials are reviewed. Based on the above analysis, this paper also pointed out the shortcomings of the current Li₃PS₄ solid electrolyte and prospected the research focus and development direction of Li₃PS₄ and other sulfide electrolytes in the future.

The anode is a key component of lithium-ion batteries, and the use of high-capacity alloy-type anodes can significantly improve the energy density of those batteries. However, alloy-type anodes suffer from low initial coulombic efficiency. This problem leads to irreversible consumption of large quantities of active lithium, which offsets the improved battery energy density. Prelithiation technology is considered a promising approach to address this problem, applicable both to anodes and cathodes. This paper summarizes research progress and application prospects for different prelithiation technologies based on a comprehensive analysis of recent literature. For anode prelithiation, the strategies of electrochemical prelithiation, chemical prelithiation, lithium-rich anode additives, and direct contact with metallic lithium, are introduced. For cathode prelithiation, strategies involving lithium-rich additives and over-lithiation are discussed. With a view toward the practical realization of different prelithiation technologies, this analysis focuses on the stability and safety, utilization rate, and cost of each prelithiation reagent. Results demonstrate that prelithiation can be an effective solution to compensate for irreversible capacity loss. Thus, it can contribute to significant improvements in energy density and cycle life of lithium-ion batteries with alloy anodes. Low cost and high safety are the keys to promote the practical application of prelithiation technology.

A flexible metal-air battery is paid lots of attention because of flexible deformation and energy storage. At present, flexible metal-air batteries are still beset by a host of problems, including battery flexibility, low conductivity and flexibility in air electrodes, and low ionic conductivity and poor mechanical properties in solid gel electrolytes. This review summarizes the structural classification of the main types of flexible metal-air batteries: one-dimensional cable-type, two-dimensional planar-type, and three-dimensional sandwich-structure type. Next, the paper examines the preparation and characteristics of non-free-standing and free-standing air electrodes. Non-free-standing electrodes are prepared using a binder to coat the catalyst onto a conductive substrate (e.g., carbon paper or cloth). Binder additives have disadvantages: they increase the inactive material content, block the pore structure, reduce electrical conductivity, and allow the catalyst to flake off. In contrast, free-standing electrodes use hydrothermal vapor-phase atomic layer deposition to grow catalysts in situ on conductive substrates. This avoids the problems noted above for non-free-standing electrodes. This review goes on to summarize related research into improving electrolyte performance and ionic conductivity (by adding different polymers, reducing polymer crystallinity, and through temperature changes). Finally, the outlook for future development of metal-air batteries is explored. Preparation of free-standing electrodes and investigation of new gel electrolyte materials are expected to become research hotspots. If the interface between air electrode and gel electrolyte can be brought into closer contact, leading to integration, the battery could be started directly by dripping electrolyte and adding metal foil. This would greatly simplify assembly and extend the potential applications of flexible metal-air batteries.

At present, China is the largest market of new energy vehicle in the world. In recent years, the vehicle fire accidents which are frequently reported have become the "roadblocks" for the large-scale popularization and application of new energy vehicles. Most of the accidents are closely related to the power battery. It is of great significance to carry out in-depth and systematic analysis on the safety failure of power battery for locating the cause of the accident and further reducing the fire accidents of new energy vehicles. Based on the fire accident analysis of new energy vehicles, this paper systematically analyzes the potential causes of failure from materials, cell design, production and manufacturing, battery pack system integration and management of power battery, so as to guide the improvement of safety quality of battery products.

Compared with hardshell batteries, pouch-type lithium-ion batteries (LIBs) have the qualities of higher energy density, causing unique thermal runaway behaviors and hazards due to their special structures. In this work, two types of LIB variations with lithium iron phosphate (LFP) and lithium nickel cobalt manganese oxide (NCM) based cathodes are experimentally investigated for failure, thermal runaway behaviors, mass loss, rupture voltage, and temperature rise after being over-charged at various current-rates (0.5～3 C). The results show that the aluminum plastic shell ruptures for LFP and NCM LIBs due to pressure accumulation inside due to side reactions during overcharging. Specifically, the LFP battery ruptures and fails when charged to a 133.4% state of charge (SOC), while the NCM battery ruptures after thermal runaway and fires when charged to about 143.8% SOC. With the increase of current rate, the rupture voltage of LIBs firstly increases and then decreases. The rupture voltage is the highest at 1.5 C, and the rupture voltages of LFP batteries are higher than those of the NCM batteries. In addition, the mass loss of LFP and NCM batteries ranges from 2.07% to 5.82% and 28.51% to 36.75%, respectively, independent of the current rate. The various characteristics of temperature rise in LFP and NCM batteries during overcharge are also revealed, and the reasons for this difference are analyzed from the perspective of the molecular structure of cathode materials. The results of this study could provide references for the selection of LIBs for electric vehicles.

The gas-electricity interconnected virtual power plant can promote the efficient use of distributed energy. An effective dispatch strategy that takes into account many uncertain factors is the key to ensuring its operational quality. On the base of the construction of a gas-electric interconnected virtual power plant including electric vehicles, wind power, photovoltaics, gas turbines, electric-to-gas equipment and electric vehicles, describing the uncertainty of wind power, photovoltaic power output, electrical load, and gas load in the virtual power plant by use of the interval optimization theory; Taking operating economic benefits, user comfort and carbon dioxide emissions as the optimization targets, and considering constraints such as power balance and equipment operating characteristics, an interval optimal scheduling plan for the gas-electricity interconnected virtual power plant is constructed, and designing an improved non-dominated sorting genetic algorithm to solve the scheduling scheme of gas-electric interconnection virtual power plant. An analysis of a case study is selected for the winter heating scenario of a gas-electricity interconnected virtual power plant in a certain area. The results show that the charging behavior of cluster electric vehicles increases the electric load during the dispatch period, and the output of gas turbines in each optimization target scheme is generally higher. The temperature is higher than the set value of 22; Considering the uncertain factors of scheduling, the interval width of the optimization results under each objective is different, which verifies that the interval optimization scheduling scheme is more authentic and more robust in terms of ensuring thermal comfort.

Flywheel energy storage is widely used in the fields of frequency modulation of power grids due to its outstanding advantages. To further improve the energy density and power density of flywheel energy storage technology, the flywheel energy storage rotors tend to be heavy and high-speed, and magnetic suspension bearings are usually used for axial unloading. The key technology is the design of permanent magnetic bearings with a large carrying capacity, high safety, and low energy loss. The permanent magnetic bearing unloading structure of the double-ring, multi-ring, and Halbach arrays currently being studied have the prominent problem of insufficient strength of the moving magnetic ring material fixedly connected with the rotor under long-term high-speed rotation. Therefore, this paper proposes a single-ring suction type axial permanent magnetic bearing topology. Taking one of the three topological structures as a design example, making full use of magnetic energy and saving materials as the design requirements, the structural parameters of the single-ring suction type axial permanent magnetic bearing are determined based on Kirchhoff's two laws. Under the influence of the flux effect, the magnetic field segmentation method is used to accurately divide the magnetic flux of each part, and the equivalent magnetic circuit model is established. The analytical calculation model of the axial bearing capacity and the axial static stiffness is derived based on the virtual displacement method, and the finite element method is used to verify the established analytical model, and the results are in good agreement, providing a theoretical basis for the design of permanent magnet bearings and subsequent flywheel dynamics analysis.

The charging process of a latent heat thermal energy storage unit inside a square cavity with a sinusoidal temperature distribution is numerically investigated in this paper by using the lattice Boltzmann method. The effect of the electric field, amplitude, wave number, and phase deviation of the temperature distribution on the melting performance is studied. Based on the numerical results, it is shown that, compared with the case without an electric field, the melting efficiency of the latent heat thermal energy storage is significantly improved, and this phenomenon becomes more pronounced with a stronger electric field. In addition, when the wave number of the temperature distribution is 1.5, the total melting time of the system is the lowest, whereas the influence of amplitude and phase deviation on the melting performance largely depends on the electric Rayleigh number.

In an operating all-vanadium redox flow battery stack, uneven electrolyte flow through each individual electrode is common, if not inevitable. Moreover, localized insufficiencies of liquid supply may become severe in a long-term operation, which not only directly affects overall stack performance, but also exacerbates harmful side reactions (including oxygen evolution, hydrogen evolution, and carbon corrosion). These reactions may in turn lead to blockages and increased resistance. This paper reports a model-based quantitative study of an all-vanadium redox flow battery stack under conditions of local liquid supply shortage. A two-dimensional steady-state simulation was carried out for charge/discharge under galvanostatic operation, focusing on the impact of local fluid supply deficiency on electrode potential and side reactions. The results show that decreased flow rate in one or several electrodes has little effect on the overall voltage of the stack, but that it does cause local sharp changes in current and ion concentrations inside the electrodes. It may also lead to an ultra-high potential gradient, causing seriously deviation of the potential from its normal value. This in turn reduces the uniformity of distribution of the main reaction and intensifies the progress of side reactions on the electrode surface, potentially compromising the energy efficiency and safety of the stacks. Since the rate of side reactions also depends on the material properties of the electrode, this paper provides qualitative conclusions based on representative working conditions. These conclusions allow general guidance to be suggested for the design and testing of flow battery stacks.

The cell module is the key component of an electric vehicle battery system, providing the energy output for the vehicle. In this study, we describe a lithium iron phosphate (LFP) pouch cell module with high energy density and high safety factor. The basis for improving battery system effectiveness and vehicle driving range lies in enhancing volume utilization and group efficiency. To improve volume utilization and bunching efficiency, we investigated the cell module in detail, both internally and externally. From an external perspective, we considered integration with the battery pack envelopes developed by mainstream vehicle manufacturers. From this analysis, we suggest configurations of cell modules to optimize the utilization of battery envelope space and propose a scheme for increasing the height of standard LFP pouch cell modules. We obtained the maximum pouch cell envelope size using theoretical mathematical formulas. Increasing the pouch cell size allows improved volume utilization in the cell modules, with corresponding increases in bunching efficiency and cell module capacity. We then simulated the lightweight cell module by finite element modeling. Once the simulated strength met the stipulated requirements, reliability experiments (e.g., for vibration and impact) were conducted to assess the safety performance of the cell module. Our conclusions are that the goals of high energy density and high safety can both be achieved, assuming a certain energy density. These findings lay the foundation for future popularization and practical application of LFP pouch cells.

Aiming at the problem of low consistency of charge state and high action times of battery cells when battery energy storage power station tracks AGC command, a new control strategy for battery energy storage power station to track AGC command is studied in this paper. Based on the brief discussion of the working principle of the Beetle Antennae Search, this paper puts forward the tracking AGC command control strategy of battery energy storage power station based on dynamic grouping technology. Firstly, the battery cells are sorted according to their charge state, and the battery cells are grouped once according to the sorting results; Then, determine the power response command of each battery pack according to its power distribution principle; Thirdly, the battery cells are grouped twice according to the difference in the action times of the battery cells; Finally, according to the principle of power distribution in the battery pack, the battery unit power response command is obtained, and the battery unit responds to the distributed power. In addition, this paper designs the evaluation system according to the effect of battery energy storage power station tracking AGC command, then constructs the fitness function required by Beetle Antennae Search, and uses Beetle Antennae Search to optimize the forced update threshold of dynamic grouping technology. The simulation results show that the control strategy improves the effect of battery energy storage power station tracking AGC command, improves the consistency of battery cell charge state, and reduces the action times of battery cell.

The randomness of new energy output and user load makes the optimal dispatching of the integrated energy system full of challenges, and a multi-park integrated energy coordinated optimal dispatching method considering the complementary cooling, heating and power and energy storage systems is proposed. First, the virtual power plant technology was introduced to aggregate the internal resources of the integrated energy system, and the energy storage devices in the park and the energy transmission devices between the parks were considered, and a multi-park integrated energy system structure under the framework of the virtual power plant was constructed; secondly, the thermal power system was established. Internal resource models such as co-supply units, energy storage systems, and cooling and heating pipelines, with the goal of maximizing system revenue, established a coordinated scheduling model for a multi-virtual power plant integrated energy system; finally, a deep reinforcement learning framework was built, and the Q value was migrated The method is introduced into the deep reinforcement learning algorithm. Based on the improved deep deterministic policy gradient algorithm, the optimal scheduling decision is made in the continuous state and action space. The effectiveness of the proposed method is verified through the analysis of calculation examples, and the results show that the coordinated and optimized dispatch of the multi-park integrated energy system based on the improved algorithm can effectively realize the reasonable allocation of resources and the complementary energy supply between the parks, and reduce the operating cost of the system.

To improve photovoltaic power output and flexibility, the construction of optical storage cooperative systems has become the mainstream trend for enhancing photovoltaic schedulability and reducing photovoltaic power curtailment. Based on the characteristics of the operating environment of the photovoltaic farm, a combined heat and power system is proposed coupled with carbon dioxide energy storage utilizing nighttime environmental cooling. Furthermore, the effect of key thermodynamic parameters on system performance under different operating modes is mainly studied. The results demonstrate that the increase of minimum temperature difference of the cool storage unit, ambient temperature at night, and the low-pressure tank pressure harms the system performance. In contrast, the increase of high-pressure tank pressure and expander inlet temperature positively affects the mode of the solar heat collection system, which works independently. In the combined working mode of the solar collector and heat pump systems, the electric energy storage, exergy, and round trip efficiencies under the design condition can reach 71.4%, 57.4%, and 87.1%, respectively, and energy storage density is 17.18 kW·h/m³. The solar factor is reduced by 35.6% compared to when the solar heat collection system is working alone. Moreover, the cool storage unit, first reheater, and heat exchanger 1 have a significant exergy loss and are the critical components for system optimization. Variations in the heat pump evaporation temperature and condenser hot water outlet temperature have a greater impact on the electrical efficiency in the mode where the heat pump system participates but has little effect on the exergy efficiency.

The traditional charging station has the problems of having a very great impact on the electrical power grid, low land utilization rate, and high construction cost. In view of the referred engineering problems, a joint optimization model of economic planning and operation of the facility configuration of a Photovoltaic-Storage-Charging integrated station is proposed. The model takes the optimal economic benefit of the integrated power station, including investment cost, maintenance cost, operation cost, and charging penalty cost, as the objective function. And it comprehensively considers the constraints, including intermittent photovoltaic power (PV) generation, energy storage stations, and energy interaction with the distribution network, and describes the charging behavior of electric vehicles based on M/G/N/K queuing theory. From the perspective of planning, make configuration decisions on photovoltaic capacity, energy storage capacity, the number of charging piles, and the number of waiting spaces. Then, from an operational perspective, make energy dispatching plans for each controlled unit integrated into the distribution network and integrated power station. Finally, the configuration results and the cost composition of integrated power stations under different scenarios, regions, and budgets are compared and analyzed using example simulations, as is the impact of optical storage configuration results and photovoltaic output uncertainty on the total profit. The results show that the economic contribution of optical storage capacity allocation to the integrated power station is greater than the number of charging piles and waiting spaces, and the planning priority should be set in the actual planning. Energy storage shows good flexibility in energy management in the integrated power station, which can improve its operation economy. Moreover, the uncertain performance of different regional environments and photovoltaic output affects the facility configuration results and profits of the integrated power station.

The energy storage device is the key to supporting the flexibility of the microgrid. Because it contains a large number of electronic devices, the DC microgrid with energy storage devices shows nonlinear characteristics. Furthermore, the parameters are time-varying. To suppress the fluctuation of bus voltage caused by the power fluctuation of distributed power sources in an isolated DC microgrid, a battery is used as the power balance device of the system, and the charge-discharge controller of the battery is designed based on the parameter adaptive backstepping method. First, a mathematical model of the energy storage system composed of a battery and a buck/boost converter is established using Thevenin's equivalent model. Thereafter, the time-varying parameters during the operation of the model are regarded as unknown, and the unknown parameters are estimated online and in real-time by using the principle of parameter adaptation. The backstepping controller, which is based on parameter estimation and Lyapunov control theory, is designed recursively to regulate the charging and discharging processes of energy storage devices and balance the power between sources and loads of DC microgrids. The simulation result shows that in the case of insufficient illumination, the energy storage device keeps discharging and stabilizing the voltage. When compared with the traditional linear PI controller and exact feedback linearization controller, an adaptive backstepping controller reduces bus voltage regulation time by 0.120 s and 0.045 s respectively, and the fluctuation of the bus voltage is reduced by 3.1% and 2.9%. respectively. In the case of sufficient illumination, the energy storage device can be charged smoothly. Compared with the backstepping controller based on fixed parameters, the response is 0.04 s faster and the voltage deviation is 0.8% smaller. The result also reveals that the backstepping controller based on the optimal parameter estimates can adjust the energy storage device to switch between charging and discharging states flexibly, and maintain the bus voltage well when the power of the distributed PV fluctuates or even completely cuts off. Furthermore, when the parameters of the system are perturbed, the robustness improves.

With the clear goal of carbon neutralization, new energy will gradually become the pillar energy of power system. Facing the characteristics of high proportion of renewable energy and high proportion of power electronic equipment in the power system, the difficulty of real-time power supply and demand balance will further increase. As the main way to improve the quality of new energy generation and stabilize the fluctuation of power grid, advanced energy storage technology has attracted much attention, but it is difficult to realize large-scale promotion due to economic constraints. The mobile energy storage system with high flexibility, strong adaptability and low cost will be an important way to improve new energy consumption and ensure power supply. It will also become an important part of power service and guarantee in the new power system in the future. Firstly, this paper combs the relevant policies of mobile energy storage technology under the dual carbon goal, analyzes the typical demonstration projects of mobile energy storage technology, and summarizes the research status of mobile energy storage technology, in order to provide reference for the multi scene emergency application of mobile energy storage technology; Then, based on the application scenario characteristics and demand analysis, the mobile energy storage technology index system is established, and the dynamic game adjustment method of mobile energy storage system cluster based on event and power regional characteristics is constructed according to the construction principle of mobile energy storage cooperation platform; Finally, combined with the double carbon goal and the demand of new power system, the application of mobile energy storage system technology is summarized and prospected.

The new energy vehicle industry is developing rapidly, and the sales of electric vehicles have repeatedly hit new highs. How to charge electric vehicles efficiently and economically at low temperatures in winter is still an urgent problem to be solved. A charging strategy at a low temperature for lithium battery systems is proposed and improved based on the principle that the battery generates heat by itself during charging. Taking the minimum single battery temperature as the judgment condition, the use of multi-stage constant current charging technology can effectively shorten the charging time and ensure sufficient charging capacity. Research and experiments show that this strategy has a good charging effect, and specific charging schemes can be formulated according to actual needs, which can effectively solve the charging problem of lithium-ion battery systems at low temperatures in winter.

A three-dimensional mathematical model of a magnesium-based solid-state hydrogen storage reactor was developed to explore factors influencing hydrogen storage reaction rates. The model was validated by comparison with experimental data in the literature. Numerical techniques were used to study how the hydrogen storage reaction rate was affected by inlet temperature, hydrogen supply pressure, and oil layer thickness of annular heat conduction oil. Simulation results show that the reactor has an optimal reaction temperature, and that the hydrogen storage reaction speed is reduced if the heat conduction oil inlet temperature is too high or too low. When the oil inlet temperature rises from 548 K to 573 K, the hydrogen storage rate increases from 3.38 g/min to 8.75 g/min. When the oil inlet temperature rises from 573 K to 648 K, the hydrogen storage rate decreases from 8.75 g/min to 3.91 g/min. The higher the hydrogen supply pressure, the faster the reaction rate, but at the expense of increasing bed temperature. A pressure rise from 0.5 MPa to 3 MPa leads to an 81.8% reduction in hydrogen storage time and a temperature rises of 65 K. For the condition of constant hydrogen storage mass, thickening the annular heat conduction oil layer on the outer wall of the reaction bed significantly improves hydrogen storage reaction speed. When that oil layer thickness is increased from 0 mm to 18 mm, hydrogen storage time decreases from 550 s to 380 s (about 30.9%). Increasing the thickness of the annular heat conduction oil layer can shorten the hydrogen storage time significantly but the volumetric hydrogen storage density is reduced. When the reservoir thickness increases from 9 mm to 18 mm, hydrogen storage time is shortened only 5 s, while the volumetric hydrogen storage density decreases from 59.68 g/L to 41.16 g/L.

The consumption, conversion, and utilization of energy are accompanied by human society's various production and life activities. With the continuous development of society, the worldwide energy crisis and environmental pollution are causing higher requirements for the efficient and rational application of energy and storage technology. Heat energy is the most common and vital form of energy. Upon deeply analyzing the primary sources, utilization and storage methods and characteristics of heat energy are essential to promote the rational and efficient use of heat energy and contribute to the sustainable development of contemporary society. This paper summarizes the current storage and technologies of heat energy from three aspects: the source form and operation status of heat energy, storage technology of heat energy, and main conversion path and heat energy technology. The ultimate goal is to explore new; green; and sustainable thermal energy resources, combine the characteristics of various thermal energy, and adopt various energy conversion and storage technologies to realize the efficient and green deployment of energy. At the same time, the development of new thermal energy storage materials and technologies, such as thermochemical heat storage, combined with new and efficient thermal energy conversion technology, causes the application of thermal energy to develop in a more scientific and reasonable direction.

The performance of a lithium-ion battery affects the driving range, safety, and reliability directly. Furthermore, as the power characteristics of the lithium-ion battery degrade, the cycle life attenuates, and the available capacity is reduced in low-temperature. Furthermore, there is a high risk of lithium plating at the surface of the anode when the battery is charged at extremely low temperatures. These factors hamper the development of electric vehicles. Battery warm-up is one of the core technologies of the battery thermal management system to alleviate the deterioration of batteries in cold weather. To this end, this paper reviewed the recent research progress of rapid heating methods, including internal self-heating, mutual pulse heating (MPH), self-heating lithium-ion battery, alternating current heating. Key performance parameters such as heating time, energy consumption, and degradation of various heating methods were also summarized. The design considerations of battery management systems in low-temperature conditions were provided, and the performance of different heating methods was compared. The results demonstrated that alternating current heating had advantages over the other methods, especially in energy consumption and degradation. Finally, future trends of battery heating methods were discussed, and more breakthroughs should be made in battery aging mechanisms and preheating strategies in a battery module/pack level. The research was helpful to promote the development of heating methods and solve engineering problems. It also provided plenty of references for the research of rapid heating methods and designing a battery thermal management system at low temperatures.

With the continuous development of renewable energy sources, there is a growing demand for various energy storage technologies for power grids. Gravity energy storage is a kind of physical energy storage with competitive environmental and economic performance, which has received more and more attention in recent years. This paper introduces the working principle and energy storage structure of gravitational potential energy storage as a physical energy storage method, analyzes in detail the new pumped energy storage, gravitational energy storage system based on structure height difference, based on mountain drop, based on underground shaft and integrated energy storage system, introduces the research status of gravitational energy storage and demonstration projects at home and abroad, summarizes and analyzes the advantages and shortcomings of various energy storage structures, and finally looks forward to the gravitational energy storage Finally, the development prospect of gravity energy storage is prospected, and development suggestions are put forward.

Battery energy storage system based on modular multilevel converter (MMHC-BESS) is suitable for medium and low voltage power grid, which is conducive to solve the problem of renewable energy grid connection. But as the number of sub-modules increases, the reliability of the system is facing great challenges. To enhance the fault-tolerant operation capability of energy storage systems, aiming at the unbalanced operation state of sub module fault, a fault-tolerant control strategy without hardware redundancy is proposed. Based on carrier phase-shift modulation algorithm, the line voltage balance and grid connected power are maintained by modulation signal reconstruction algorithm. In addition, in order to improve the utilization rate of energy storage battery capacity, a SOC equalization strategy based on fault-tolerant control is proposed. Through zero-sequence voltage injection and dynamic adjustment of in-phase SOC equalization factors, an inter-phase and in-phase two-stage SOC equalization strategy is constructed. Finally, a simulation model based on PLECS is built to verify the feasibility and effectiveness of the proposed strategy.

The safety problem of thermal runaway of lithium ion battery has always been a pain point for the development of electric vehicles. In this paper, the thermal runaway release gas and its flammability limit and flame propagation characteristics of ternary 18650 lithium-ion battery at SOC of 50% and 100% were studied by experiment and simulation. Firstly, the heating triggered thermal runaway experiment is carried out in the accelerated calorimeter. The vented gas was collected and its components proportion was then detected using the gas chromatograph to study the effect of SOC on the comprehensive characteristics of thermal runaway gas production. The laminar flame speed and flammability limit of heat release gas at different initial temperatures and pressures were simulated. The results show that when the initial temperature of heat release gas is high, the lower flammability limit is close to 10%, which has a high ignition risk; The lower flammability limit decreases linearly with the increase of initial temperature, and the upper flammability limit increases linearly with the increase of initial temperature; When the initial pressure changes, it has little effect on the lower flammability limit, and the upper flammability limit increases with the increase of pressure.

The discharge current of the UAV's lithium battery will change greatly under the complex flight attitude of the UAV, making it difficult to accurately estimate the remaining power and other state parameters of the UAV. In response to this problem, this paper proposes an improved gray wolf algorithm (IGWO) optimized particle filter (PF) algorithm, which estimates the SOC through the distribution of particles. Particles are characterized using gray wolves in this method. By setting the wolf pack location update mechanism, the particles are continuously approaching the true posterior probability distribution, thereby accurately estimating the remaining power of the UAV lithium battery. First, the complexity and accuracy are comprehensively considered. The second-order Thevenin equivalent circuit constructs the lithium-ion battery model, calculates the observation equation and the state equation, and then completes the parameter identification online by the least square method based on the forgetting factor, and then uses the gray wolf algorithm that introduces the Levi flight strategy to optimize the PF algorithm. Estimate the drone's remaining power. Finally, simulate and verify the IGWO-PF algorithm, the PF algorithm, and the UKF algorithms using MATLAB. The results show that the IGWO-PF algorithm can converge well to the actual value in the SOC estimation result and is more accurate and stable for the SOC estimation error within 1% than the traditional algorithm error. This research can more accurately estimate the remaining power of the drone during the flight.

In this paper, a structure for preventing the thermal spread of prismatic cells is studied via numerical simulation. The thermal runaway model was established for 50 A·h prismatic ternary lithium-ion batteries used in vehicles based on the thermal runaway side reaction mechanism in the electrodes and electrolyte. The model is verified by comparing it to existing research to demonstrate that the established thermal runaway model has high accuracy. Based on the verified single battery thermal runaway model, a battery module thermal protection structure was established in which each battery cell was assembled with a thermal sleeve. The bottom of the thermal sleeve was connected with a minichannel cold plate for heat dissipation. Insulation materials were filled between batteries to prevent heat from spreading to adjacent batteries due to thermal loss. The results show that the proposed thermal protection structure can effectively block the thermal spread of the battery module compared with the configuration without a thermal sleeve. Moreover, the influence of the thermal resistance of the insulation layer, the height of the thermal sleeve, and the height of the thermally conductive plate on the thermal spread of adjacent batteries was analyzed based on the proposed thermal protection structure. The research shows that the thermal resistance of the insulation layer is above 0.03 m²·K/W, and the adjacent #2 battery does not have thermal runaway. In addition, the height of the thermal sleeve should not be higher than 10 mm considering the impact of actual engineering system quality factors, and the height of the thermally conductive plate should be between 60 and 65 mm, which can be used to prevent the thermal spread of the battery module. The thermal protection structure and parameters presented in this paper provide a reference for the thermal safety design of battery packs.

The state of heath (SOH) of the power battery of an electric vehicle is one of the key monitoring indicators of its battery management system. Accurate evaluation of it is of great significance for the safe and reliable operation of the vehicle. However, existing power battery SOH evaluation methods have problems such as unsatisfactory evaluation accuracy and high computational complexity. For this reason, a power battery health status evaluation method based on an improved Temporal Convolutional Network (TCN) model is proposed. This method first extracts three health factors of equal voltage rise time, equal current fall time, and voltage rise value from the power battery charging data, and uses Pearson correlation coefficient to verify the correlation between them and the battery capacity; then according to the TCN model The receptive field adjusts the encoder-decoder structure, and uses the trained encoder to extract features of the input sequence to obtain the short-term expression of the long-term sequence; finally, the TCN model is used to capture the characteristic time sequence and the battery SOH. Causality, to achieve accurate assessment of the health status of the power battery. The proposed method is applied to the public battery data set, and the experimental results are compared with the widely used time series analysis methods and methods used in related literature. The results show that the proposed method can reduce the root mean square error and absolute average error by 0.0012 respectively. And 0.0008, the calculation time required for the same training times is reduced by 3.4%.

Lithium-ion batteries demonstrate a noticeable volume swell before thermal runaway occurs. Therefore, studying the changing law of power battery swelling force is significant for improving battery performance and early warning safety. This study explores the changing law of the swelling force for ternary/graphite batteries when charging at various temperatures and rates. The increase in the swelling force of the power battery is minimum when charged at 25 ℃. Consequently, the low ambient temperature causes lithium ions to accumulate on the surface of the graphite layer, thereby increasing the battery thickness and swelling force. Moreover, the higher the ambient temperature, the larger the volume of the power battery; an SEI film is produced during charging, leading to a greater expansion force. When the power battery is charged at different rates, the swelling force gradually rises with an increase in charging rate, possibly because the high rate charging increases the battery temperature; the SEI film is formed on the material's surface. The CT scan results accurately quantify and analyze the thickness variations of the battery during the charging process. The capacity differential curve (dQ/dV) during the charging process reveals that the variation in the growth trend of the swelling battery force is primarily due to the various phase transitions of the positive and negative materials in the different charging stages. Then, the change characteristics of the expansion force in the charging process of the power battery are revealed from the mechanism level.

Lithium-ion power batteries are the primary power source of new energy vehicles. Hundreds of cells are placed together and highly integrated into a confined space to improve the energy density of the battery system of an electric vehicle. When thermal runaway (TR) occurs unexpectedly in a single battery pack, the heat is easily transferred to the surroundings rapidly, resulting in the TR of the entire battery system and causing severe results. Therefore, preventing thermal propagation is vital to ensure battery safety. In this paper, a multichannel liquid cooling system with a serpentine wavy configuration is utilized for cooling a 18650 type lithium-ion battery pack. Furthermore, we explore the effectiveness of cooling measures on TR propagation in the battery pack when the target battery is triggered by heat. The results show that the TR of the target battery rapidly propagates toward the whole battery module without cooling measures. However, a temperature platform appears in the target battery approximately one hour after it is heated, and the target battery with liquid cooling measures does not experience TR in the same thermal abuse situation. Increasing the heating power to accelerate the progress of TR of the target battery prevents the surrounding batteries from being triggered when TR occurs in the target battery. Compared to the case without cooling measures, the cooling water of the management system can timely dissipate the heat generated by the battery reaction, resulting in the prolongation of the time between the exothermic side reaction of the battery material and TR. As a result, this reduces the heat transfer from the triggered battery to the neighbor batteries, thereby avoiding thermal propagation.

The State of Health (SOH) of lithium batteries is a key parameter to characterize the actual useful life. SOH is not directly measurable, and a combined CNN-LSTM and GRU estimation method based on health feature parameters is proposed to further improve the accuracy of SOH estimation. Firstly, the health feature parameters are initially selected from the Li-ion battery charging curve, and the health features are extracted by Spearman correlation coefficient. Secondly, Convolutional Neural Network (CNN) is used to extract local features of health features and Long Short-Term Memory (LSTM) to mine data time series features to construct a CNN-LSTM fusion neural network. Subsequently, the CNN-LSTM and the Gated Recurrent Unit (GRU) are combined to form a combined SOH estimation model by adaptive weighting factors. Finally, the validation is based on the NASA lithium battery dataset 5, 6, 7, and 18 battery parameters. The experimental results show that the estimation accuracy of the proposed combined model is better than that of the single model, and the estimation error is further reduced.

Energy storage technology, which has attracted extensive attention all over the world, is the key to supporting energy transformation and the smart grid. Due to its high energy density, long cycle life, and environmental friendliness, the lithium-ion battery has become one of the preferred storage carriers for large-scale energy storage. The magnitude of energy storage has been observed to increase continually. However, fire accidents have occurred frequently in lithium-ion battery energy storage systems, limiting their further application. Because of this problem, this study compares the representative safety test standards of lithium-ion battery energy storage at home and abroad, for example, foreign standards such as IEC 62619, IEC 63056, UL 1973, and UL 9540A, as well as national, industrial, and alliance standards such as GB/T 36276 and T/CNESA 1004. Further, the test methods for thermal runaway are analyzed at the cell, module, unit, and installation levels according to the characteristics of the energy storage system. Finally, the shortcomings of the current standards are revealed, and several proposals are advanced to promote the safe and efficient operation of energy storage systems.

A lithium-sulfur battery is a kind of lithium battery with sulfur as the positive electrode and lithium as the negative electrode. It has become a research hotspot and the development direction of the emerging technology in the field of fuel cells, with the characteristics of abundant raw material reserves, low cost, and environmental protection. This paper takes global lithium-sulfur battery technology patents as the research object and uses patent data mining and topic clustering methods to analyze the overall development trend of global patent applications for this technology, geographical distribution, patent technology composition and efficacy, applicant technology composition and topic clustering, as well as the technology layout of major institutions, and uses visualization methods to show the current research hotspots and technological development trends in this field of technology. There were suggestions made to accelerate technology development and innovation, follow national policy guidance, strengthen technical cooperation among institutions, and improve patent technology layout and intellectual property protection strategies.

The proposal of the "dual carbon" goal has accelerated the transition of my country's energy structure from traditional fossil energy to renewable energy, but the high penetration rate of renewable energy power generation has brought many problems to the power system, and the solution of these problems has given birth to energy storage technology. This paper first introduces the development status of China's energy storage technology. With the encouragement of China's policies and industrial demand, the energy storage industry is developing rapidly, and in accordance with current policy guidance and requirements, energy storage technology still has huge room for development. However, this will inevitably lead to a more prominent shortage of energy storage technology professionals. Secondly, this paper elaborates on the current status of China's energy storage discipline construction. In order to alleviate the pressure of the shortage of energy storage talents, major universities in China are actively planning to apply for energy storage majors, and 26 universities have added the majors of "Energy Storage Science and Engineering". Finally, in the context of the new engineering discipline, this paper puts forward a conception of the construction of an energy storage discipline system, focusing on the goal of cultivating industrial applied talents in the energy storage field, following the talent training ideas of the three dimensions of quality, knowledge, and ability, following the theme of "interdisciplinary integration" curriculum design. Build a curriculum system for the energy storage subject, and propose a talent training model that combines school-enterprise integration, integration of science and education, and 5+4+1 assessment. To achieve a breakthrough in the energy storage discipline "from 0 to 1", we are committed to cultivating "high-quality, strong foundation, and innovative" outstanding talents in the energy storage industry.