Etransportation最新文献

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.

Given the exponential increase in the number of lithium-ion batteries (LIBs) used in electric cars and the sizeable quantity of waste produced at the end of their lifespans, efficient recycling of used lithium-ion batteries offers tremendous promise for practical application. While considerable efforts have been devoted to the recycling of cathode materials and other valuable components in spent lithium-ion batteries, sufficient attention has not been directed towards the spent anode graphite. Given the risks associated with limited resource supply and environmental pressure, the regeneration of spent graphite anodes from electric vehicle batteries has become a critical issue. As a preferred option, the direct regeneration strategy has been innovatively proposed to recover targeted graphite materials. To better comprehend this topic, three types of graphite are highlighted and categorized based on the source of the LIBs. Their special features, advantages, and challenges are also summarized and evaluated. More significantly, it is anticipated that the outcomes of this work could emphasize the importance of graphite recycling in the overall recycling of the spent lithium-ion battery industry.

Thermophysical parameters, including the specific heat and thermal conductivity of lithium-ion batteries (LIBs), are the key parameters for the design of battery thermal management systems in electric vehicles. The evaluations of internal temperature distribution and even the thermal safety characteristics of the batteries depend highly on these thermophysical parameters under either live operation or repose condition. In this paper, the experimental studies of the specific heat and thermal conductivity of LIBs are reviewed and discussed. This review classifies the experimental studies into ex-situ and in-situ measurements. The ex-situ measurements, based on the dissection of the battery, may differ from realistic scenarios and thus the obtained parameters may not be fully applicable for thermal prediction of practical battery systems. Contrarily, in-situ measurements better represent the realistic characteristics without dismantling the battery, which can be further categorized into weighted average method, heat flow method, dedicated equipment including accelerating rate calorimeter (ARC), calibration calorimeter in insulation, self-made calorimeter method, and so on. Due to the short test time and good size adaptability, unsteady-state in-situ measurement techniques, including the calibration calorimeter and quasi-steady state techniques, are becoming the promising research directions in the future, especially for the simultaneous determination of multiple thermal parameters. The large data scatterings are pointed out based on the existing results, and the underlying mechanisms are scrutinized. To guarantee measurement accuracy, it is indispensable to calibrate the heat loss and benchmark with standard sample tests together with rigorous uncertainty analysis. The thermophysical parameters should be determined under different temperatures, states of charge (SOC) and aging conditions to enable accurate prediction of temperature profiles and degradation for LIBs with ever increasing energy density and safety risk.

All-solid-state lithium batteries employing solid electrolyte instead of organic liquid electrolyte and separator have been regarded as one of the most favorable candidates for next generation energy storage devices due to their unparalleled safety and energy density. Recently, significant progresses have been made on developing suitable solid electrolytes for all-solid-state lithium batteries with high ionic conductivity, wide electrochemical window and favorable electrode compatibility. Nevertheless, owing to the brittle nature of inorganic solid electrolytes and limited mechanic property of solid polymer electrolytes, the typical thickness of solid electrolyte layers is excessively thick, which prevents further enhancing the energy density of all-solid-state rechargeable batteries. In this short review, we summary recent research progresses on solid electrolyte membranes based on wet coating, frame support and dry film methods. In particular, the critical parameters such as thickness, conductivity and mechanical property are discussed in detail. Finally, the future development directions of the solid electrolyte membranes are proposed.

This study investigates the electric vehicle thermal management system performance, utilizing thermal energy storage and waste heat recovery, in response to the imperative shift toward carbon-free electric vehicles to overcome the challenge of low energy efficiency in the thermal management system. The heat generation according to the electrical load on the battery was calculated based on experimental data. The thermal performances of the cabin, power electronic thermal management, and battery thermal management system were explored under various operating conditions at different ambient temperatures. A fully charged thermal energy storage system, including low- and high-temperature phase change materials and waste heat recovery systems, was applied in summer and winter. The total energy consumption for cooling and heating saved to a maximum of 65.9 % in summer and 26.2 % in winter. The mileage extension rate was calculated by distributing the power demand according to the vehicle exterior and motor performance of the battery. Thus, by directly saving the thermal parasitic electrical energy and using it to extend the driving mileage, the electric vehicle achieved a mileage extension of 24.2 % in summer and 18.6 % in winter.