Etransportation最新文献

Ammonia and hydrogen, as carbon-free clean energy, can be converted and applied in various scenarios. They can also be mixed to achieve synergistic efficiency. To promote the carbon-neutral development of heavy-duty vehicles, this paper studies an ammonia-hydrogen powertrain equipped with both a fuel cell and an engine (FCEAP). This powertrain efficiently allocates energy between multiple power sources and exploits the potential of ammonia-hydrogen synergy fuel. The modeling of FCEAP is based on experimental data obtained from engine bench tests, and the control strategy enables real-time control. Additionally, FCEAP undergoes multi-objective co-optimization using the non-dominated sorting algorithm-III (NSGA-III). By optimizing ammonia consumption, acceleration time, and manufacturing cost, Pareto solutions for the configuration and control strategy parameters are obtained. Furthermore, FCEAP is compared to ammonia-hydrogen powertrains equipped with either a fuel cell (FCAP) or an engine (EAP). The trade-off solutions indicate that FCEAP effectively balances energy consumption and manufacturing cost compared with FCAP and EAP. A comprehensive analysis of the energy flow distribution within various ammonia-hydrogen powertrains is conducted, revealing the operational processes and details of each component. The proposed ammonia-hydrogen powertrain represents an important technological pathway for achieving carbon neutrality in the future heavy-duty long-haul trucks industry.

Electric vehicle (EV) technology addresses the challenge of reducing carbon and greenhouse gas emissions. The power battery, which serves as the energy source for EVs, directly impacts their driving range, maximum speed, and service life. Considering the high energy density requirements for future EVs, lithium metal anodes possess several advantages such as high theoretical capacity, high energy and power density, and low electrochemical reduction potential which enable them to be a promising material for next-generation batteries. However, lithium metal anodes suffer from short cycle life and safety concerns due to the formation of dendritic and moss-like metal deposits that impede battery performance and reliability. This review will feature the recent advancement of functional separators to tackle these challenges. Firstly, this review presents a comprehensive review of the growth mechanism of lithium dendrites and delineates the underlying processes leading to battery failure. This aims to deepen understanding, which serves as a fundamental basis for classifying separators. Then, according to the growth of lithium dendrites and the failure process of lithium metal batteries, namely lithium-ion nucleation, growth of lithium dendrites, penetration of lithium dendrites into the separator, thermal runaway and even failure of the battery, four types of functional separators for different stages are proposed. The functions of these types of separators are to prevent the nucleation of lithium ions and regulate the uniform deposition of lithium ions, detect and eliminate dendrites, increase the mechanical strength of the separator and enhance the thermal stability and flame-retardancy of the separators, respectively. Finally, the recent advances of the above strategies are reviewed and discussed, existing critical problems are identified, and the future perspective of functional separators for the safety of lithium metal batteries is also discussed.

This study addresses the common occurrence of cell-to-cell variations arising from manufacturing tolerances and their implications during battery production. The focus is on assessing the impact of these inherent differences in cells and exploring diverse cell and module connection methods on battery pack performance and their subsequent influence on the driving range of electric vehicles (EVs). The analysis spans three battery pack sizes, encompassing various constant discharge rates and nine distinct drive cycles representative of driving behaviours across different regions of India. Two interconnection topologies, categorised as “string” and “cross”, are examined. The findings reveal that cross-connected packs exhibit reduced energy output compared to string-connected configurations, which is reflected in the driving range outcomes observed during drive cycle simulations. Additionally, the study investigates the effects of standard deviation in cell parameters, concluding that an increased standard deviation (SD) leads to decreased energy output from the packs. Notably, string-connected packs demonstrate superior performance in terms of extractable energy under such conditions.

In electrochemical energy storage stations, battery modules are stacked layer by layer on the racks. During the thermal runaway process of the battery, combustible mixture gases are vented. Once ignited by high-temperature surfaces or arcing, the resulting intense jet fire can cause the spread of both the same-layer and upper-layer battery modules. The direction of thermal runaway propagation of the battery involves both horizontal and vertical dimensions. Currently, there is a lack of quantitative research on the multidimensional fire propagation mechanism and heat flow patterns of the “thermal runaway-spontaneous heating-flaming” process in lithium-ion phosphate batteries. This paper conducts multidimensional fire propagation experiments on lithium-ion phosphate batteries in a realistic electrochemical energy storage station scenario. It investigates the propagation characteristics of lithium-ion phosphate batteries in both horizontal and vertical directions, the heat flow patterns during multidimensional propagation, and elucidates the influence mechanism of flame radiation heat transfer on thermal runaway propagation. Research indicates that when the heat transfer reaches 56.6 kJ, it triggers the fire propagation of cell. The heat required to trigger the fire propagation of a battery module is 35.99 kJ. In vertical fire propagation, the thermal runaway propagation time of the upper module is shorter (reduced from 122.3 s to 62.3 s), the temperature is higher (increased from 610.6 °C to 645 °C), the heat release is greater (increased from 205.69 kJ to 221.05 kJ), and the combustion is more intense. The research results of this paper can provide a theoretical basis and technical guidance for the fire safety design of energy storage stations.

In light of the widespread commercialization of proton exchange membrane fuel cells (PEMFCs) on a global scale, the expeditious resolution of challenges pertaining to cost and performance has become imperative. The strategy of fabricating cathode featuring ultralow Pt loading stands out as a pivotal technical avenue for enhancing the cost competitiveness of PEMFCs. Whereas, within low-Pt electrode, local oxygen transport resistance (R_Local), emanated from the oxygen transport process through the ionomer film positioned on Pt surface, assumes a paramount role in the manifestation of concentration polarization losses. This comprehensive review encapsulates the latest strides in understanding and addressing R_Local, while concurrently delineating prospective for future research endeavors in this domain. Commencing with an elucidation of the genesis of R_Local, the micro-characterization technologies in discerning Pt/ionomer interface structure are systematically scrutinized. Subsequently, a retrospect of methodologies and theoretical models for quantifying R_Local is presented, encompassing both experimental test and numerical simulation. After that, we critically examine a spectrum of innovative and efficacious strategies aimed at mitigating R_Local, including modifying Pt surface, designing carbon support, tuning ionomer, optimizing solvent, and constructing catalyst layer. Finally, this review proffers forward-looking viewpoints on the research orientation and methods of R_Local in future investigations, which significantly contribute to the cognition of local oxygen transport and, concomitantly, design of high-performance fuel cell electrodes.

The increasing penetration of Electric Vehicles (EVs) presents significant challenges in integrating EV chargers. To address this, precise smart EV charging strategies are imperative to prevent a surge in peak power demand and ensure seamless charger integration. In this article, a smart EV charging pool algorithm employing optimal control is proposed. The main objective is to minimize the charge point operator’s cost while maximizing its EV chargers’ flexibility. The algorithm adeptly manages the charger pilot signal standard and accommodates the non-ideal behavior of EV batteries across various vehicle types. It ensures the fulfillment of vehicle owners’ preferences regarding the departure state of charge. Additionally, we develop a data-driven characterization of EV workplace chargers, considering power levels and estimated battery capacities. A novel methodology for computing the EV battery’s arrival state of charge is also introduced. The efficacy of the EV charging algorithm is evaluated through multiple simulation campaigns, ranging from individual charger responses to comprehensive charging pool analyses. Simulation results are compared with those of a typical minimum-time strategy, revealing cost reductions and significant power savings based on the flexibility of EV chargers. This novel algorithm emerges as a valuable tool for accurately managing the power demanded by an EV charging station, offering flexible services to the electrical grid.

The thermal safety of battery pack has attracted much attention accompany with the growth in electric vehicles (EVs) in recent years. Although various battery thermal management systems (BTMS) are investigated by many research, the thermal runaway propagation (TRP) of battery packs under extremely abused conditions is just at the level of structural design and theoretical model. How to explore an innovative technology to improve the integrated thermal safety including the BTMS and TRP is still a great challenge. In this study, a multifunctional flame-retardant paraffin (PA)/styrene-butadiene-styrene (SBS)/expanded graphite (EG)/methylphenyl silicone resin (MPS)/triphenyl phosphate (TPP) composite phase change material (PSEMT) has successfully prepared. Besides, it has applied in 26650 ternary power battery modules. When the proportion of MPS and TPP is 1:2, the experimental results reveal that PSEMT possesses high thermal stability, and excellent flame-retardant properties owing to synergistic flame-retardant effect with phosphorus and silicon. Further, the cylindrical 26650 battery module with PSEMT exhibits optimum thermal management performance. Even at 2C discharge rate after ten cycles, the maximum operating temperature of battery module can still be maintained below 50 °C, and the maximum temperature difference is controlled within 4.6 °C. Additionally, it displays an excellent thermal runaway suppression through triggering by multiple heat sources. What's more, the battery with PSEMT can suppress the peak temperature and delay the occurrence time of thermal runaway. Therefore, it can be induced that the battery module with PSEMT can effectively avoid heat accumulation and significantly reduce its thermal safety risk. This study offers a new solution with promising prospects from the perspectives of energy storage and EVs, for balancing the temperature inconsistencies in batteries and suppressing thermal runaway in the battery packs.

With the pressing need to expedite the transition toward a greener marine industry, energy-efficient and eco-friendly lithium-ion batteries (LIBs) are increasingly favored. However, compared to land applications, marine environments pose unique challenges to the utilization of LIBs, thereby necessitating targeted safety measures. In this study, prismatic LIBs (PLIBs) are subjected to standard salt spray tests to emulate marine environments, and the resultant morphological changes and external voltage response of the batteries under the corrosion behavior are analyzed. Subsequently, the impacts of the salt spray environment on the electrochemical performance of PLIBs are assessed through a range of characterization techniques including scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and charge-discharge test. Finally, quasi-static ball indentation tests are carried out on the corroded batteries to study the behaviors under mechanical abusive loading scenarios. Results reveal that the most prominent effect of the salt spray environment on the batteries is the occurrence of swelling, attributable to the imperfect sealing of the battery tabs. This study represents an innovative exploration of the viability of LIBs in the marine environments, providing fundamental theoretical guidance for early detection of battery corrosion and collision risks, as well as facilitating protective design considerations.

Battery state-of-charge (SOC) is an evaluation metric for the electric vehicles' remaining driving range and one of the main monitoring parameters for battery management systems. However, there are rarely data-driven studies on multi-step prediction of battery SOC, which cannot accurately provide and realize electric vehicle remaining driving range prediction and SOC safety pre-warning. Therefore, this study aims to perform SOC multi-forward-step prediction for real-world vehicle battery system by a novel hybrid long short-term memory and gate recurrent unit (LSTM-GRU) neural network. The paper firstly analyses the characteristics of correlation analysis and adopts similarity metric method to reduce the parameter dimensionality for the input neural network. Then the advantages between LSTM-GRU, LSTM, GRU, and long short-term memory and convolutional neural network (LSTM-CNN) are analyzed by comparing experimental and real-world vehicle data, and the effectiveness and accuracy of the proposed method is demonstrated. In addition, the proposed method robustness is verified by adding noise data to the input parameters. In this study, the prediction results were validated with real-world vehicle data in spring, summer, autumn and winter, and the proposed method achieved a minimum MAPE and MAE of 1.03% and 0.73 for summer conditions, while the minimum standard deviation of prediction was 0.06% for experimental conditions. The research process shows that the method has high accuracy when applied to large data and is expected to be applied to real-world vehicle battery system SOC multi-forward-step prediction in the future.

The ongoing transition to decentralized renewable energy sources and sector-coupled consumers is reshaping the energy system. Changes at lower grid levels can stress lines and transformers. Crucial for a successful local energy transition are grid relief measures. Battery electric vehicles contribute to higher loads on grid equipment but also offer flexibility. This paper assesses the influence of four different charging strategies for battery electric vehicles across five representative low-voltage grids based on the grid development plan in Germany for the years 2021, 2037, and 2045. Results indicate that grid stress, specifically capacity stress, will emerge by 2037 and 2045. Decentralized photovoltaic systems are the primary contributors to this stress due to high simultaneous generation. Up to nearly 20 % of photovoltaic power may need to be curtailed in 2045, especially in rural grids during the summer, to prevent overloads.

Charging strategies linked to wholesale power market prices can inadvertently lead to higher consumption-induced grid overloads, necessitating the consideration of local grid restrictions. Implementing grid-friendly charging strategies, such as reduced charging power or alignment with local photovoltaic production, can mitigate those grid overloads from almost 8 % down to 0.11 %. However, these charging strategies have limited impact on photovoltaic-induced overloads due to the low number of connected battery electric vehicles during the day.

In summary, appropriate charging strategies can ease low-voltage grid stress and are suitable measures to manage the challenges of decentralized energy transition and battery-electric vehicle adoption.