Energy technology最新文献

Lithium-ion capacitors (LICs), as the next generation of supercapacitors, combine the high power density and long cycle life of supercapacitors with the high energy density of lithium-ion batteries, presenting broad prospects for applications and becoming a focal point of research in academia and industry. Safety concerns regarding LICs, particularly the crucial issue of thermal safety, have garnered widespread attention. This study investigates the thermal abuse, electrical abuse, and mechanical abuse of 1100 F LICs, including overheating, overcharging, overdischarging, needling, extrusion, and short circuit tests, with real-time monitoring of temperature, gas emissions, and voltage to explore thermal runaway mechanisms. The results demonstrate that LICs remain safe under abusive conditions, with no occurrences of fire or explosion hazards.

Solar energy utilization in the transportation sector is important for reducing fossil fuel consumption and achieving the grant goal of carbon neutrality. The photovoltaic noise barriers (PVNB) are recognized as a potential alternative for electric vehicle charging. This study aims to evaluate the power generation capabilities of both monofacial photovoltaic noise barriers (mono-PVNB) and bifacial photovoltaic noise barriers (bi-PVNB) when applied along roads with different directions and shading conditions. Results show that the daily yields of bi-PVNB facing west, southwest, south, and southeast are 754, 819, 1101, and 894 Wh, respectively. In contrast, the daily yields of mono-PVNB are 459, 711, 968, and 764 Wh. The bifacial gains are, respectively, 64, 15, 14, and 17%. The influence of partial shading on PV power generation is tested, and sharp decrease is observed when horizontal shading reaches 20% and vertical shading reaches 40%. In summary, the bi-PVNB shows satisfactory power generation ability with different orientation and shading conditions. Under Shenzhen climate, the annual power generation of bi-PVNB along east–west, north–south, southeast–northwest, and southwest–northeast direction roads are predicted to be 304, 325, 342, and 335 MWh per kilometer.

Overcharging is a primary cause of thermal runaway in ternary lithium-ion batteries, often leading to serious safety incidents. Early detection of thermal runaway during overcharging is therefore critical. This study investigates a 5 Ah ternary lithium battery pack, applying appropriate preload force to simulate real-world conditions. Various overcharge experiments are conducted under different conditions, and changes in battery voltage, temperature, and expansion force are thoroughly analyzed. The results indicate that under the same initial conditions, higher charging rates accelerate the temperature rise in the lithium battery. Additionally, the internal gas generation rate increases, causing a faster rise in edge pressure and leading to earlier battery cracking. Building on these findings, a three-level early warning algorithm is developed, which comprehensively considers voltage, temperature, and expansion force changes. Experimental validation demonstrates that this algorithm can accurately identify the current stage of thermal runaway and detect the transition to the third warning stage 604 s before complete failure, thus providing critical protection for the safe operation of the battery pack. This study offers valuable guidance for enhancing the monitoring and early warning capabilities of battery management systems.

Intermittency is an inherent characteristic of photovoltaic (PV) power generation and results in high ramp rates of the generated power. This article explores the feasibility of integrating supercapacitors at the PV module level, aiming to reduce the power fluctuations of PV systems and control the power ramp rate into the power grid. First, an equivalent circuit model of a single-phase grid-connected PV system based on module-based supercapacitors is proposed, and a power ramp rate control scheme is established. Then, experimental setups for a single-phase grid-connected PV system based on module-based supercapacitors are implemented, and the computational model is verified through experiments. Finally, using the verified computational model and the proposed control scheme, the module-based supercapacitor sizes for different PV system sizes (PV module, rooftop, small system, large system) that meet specific ramp rate requirements under different ramp rate limits (5, 10, 15% min⁻¹) are compared. Case studies show that large-scale PV systems with geographical smoothing effects help to reduce the size of module-based supercapacitors per normalized power of installed PV, providing the possibility for the application of modular supercapacitors as potential energy storage solutions to improve power ramp rate performance in large-scale PV systems.

Green ammonia and hydrogen from renewable energy sources have emerged as crucial players during the transition of the chemical industry from a fossil energy-dominated economy to one that is environmentally friendly. This work proposes a green ammonia synthesis system driven by synergistic hydrogen generation using alkaline water electrolyzers (AWE) and proton exchange membrane electrolyzers (PEMEC). The effects of hydrogen-production ratios of PEMEC and AWE on the thermodynamic and economic performance of the system are compared and analyzed via multi-objective optimization. The findings showed that an increase in the amount of hydrogen produced by PEMEC improves the system's energy efficiency, but the payback period is delayed because of the PEMEC high initial investment cost. The techno-economic performance of the system at a 1:1 ratio of PEMEC to AWE hydrogen production are investigated considering the system level heat integration based on the pinch point analysis method to maximize the heat recovery. The results show that increasing the operational temperature, the pressure of the electrolyzer, and the ammonia synthesis pressure will enhance the system's thermal performance. Economic analysis shows that reducing electricity prices and electrolyzer investment costs will be the key to achieving the economic feasibility of the green ammonia system.

In recent years, the rapid advancement of self-powered wearable electronic devices has propelled the research focus toward flexible electrodes for single electrode triboelectric nanogenerators (STENG). However, there is currently a lack of reported methods for large-scale preparation and high-efficiency molding of these flexible electrodes. In this study, PBAT-co-PEG/NaSCN blends-based ionic conductive thermoplastic elastomer (ICTE) are successfully prepared by initially conducting melt transesterification, followed by melt blending. The STENG, featuring an ICTE electrode, exhibited a remarkable open-circuit voltage of 50 V, short-circuit current of 460 nA and charge transfer of 16 nC. With the aid of Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC), the conduction mechanism of ICTE is elucidated. Due to good fluidity and processing performance, bars of ICTE suitable for mechanical properties test could be conveniently prepared via injection molding, which demonstrates the tensile strength and elongation, 13 MPa and 2500%, respectively. A 4 × 4 cm² STENG fabricated with ICTE electrode could not only have good energy-harvesting performance but also could be used in a sensor to sense the motion detection. The ICTE, with its simple and environmentally friendly preparation process and high-efficiency molding, exhibits a promising prospect in the large-scale preparation and application of flexible STENG.

As electric vehicles (EVs) emerge as the backbone of modern transportation, the concurrent uptick in battery fire incidents presents a disconcerting challenge. To tackle this issue effectively, it is imperative to pierce beyond the superficial causes of lithium-ion battery (LIB) failures—such as equipment malfunctions or physical damage—and to excavate the underlying triggers. This nuanced approach is pivotal to refining EV quality, diminishing fire incidents, and bolstering consumer trust. While issues that are readily apparent to consumers, like spontaneous battery degradation, vehicular collisions, or submersion, may seem like the primary culprits, they merely scratch the surface of a more complex problem. The true mechanisms behind these fires involve internal and external short circuits, yet these explanations fall short in providing actionable guidance for manufacturers or end-users to enhance LIB safety. The heart of the issue is identifying the root causes that bridge failure triggers and resulting fires. A total of 20 root causes are identified, linking them to real-world scenarios like overcharging causing internal shorts or wire harness issues leading to external shorts. With this insight, stakeholders can more effectively investigate and understand EV LIB fire incidents, bolstering EV safety and reliability, and promoting consumer confidence.

The seawater desalination and wastewater treatment by the interfacial solar steam generation (ISSG) technique is considered as a green, economical, sustainable, low-energy-consumption, and potential fresh water production strategy to solve the water shortage and energy crisis. Recently, efficient biomass-based ISSGs (BISSGs) have been widely reported due to its efficient photothermal conversion efficiency and good hydrophilic performance. The BISSGs with efficient solar absorption and water transmission performance by design and optimization their various forms and structures and related photothermal properties is also significantly great for its scale application. This review highlights recent advancements in 3D BISSG systems, with a focus on the design and optimization of photothermal conversion materials and substrate materials. Then, the review also discusses the potential of biomass materials in BISSG applications, aiming to provide a theoretical basis for developing cost-effective, efficient, and sustainable water purification technologies. Finally, the challenges and development prospects of the BISSG system in basic research and practical application will provide theoretical guidance for the further development of this technology.

Two-dimensional (2D) nanofillers can effectively improve the performance of nano-dielectrics by having larger aspect ratios and larger electron-scattering interfaces than one-dimensional (1D) nanofillers and zero-dimensional (0D) nanofillers; the formation of a large interfacial area in the polymer matrix effectively traps or scatters the mobile charges and increases the curvature of the propagation paths of the electric tree, thus effectively increasing the breakdown strength and the energy-storage density of nanodielectrics. In this article, the intrinsic mechanism of 2D nanodielectrics is elaborated using percolation theory, microcapacitance theory, interfacial model, and ping-pong racket model. Surface modification, oriented alignment, and multilayer structural design are reviewed to enhance the dielectric properties of nanodielectrics. Additionally, an outlook on the multiple challenges and potential opportunities in the process of preparing energy-storage capacitors with excellent performance is provided.