The capacity of power batteries is an important factor affecting the structural composition of fuel cell vehicles. By comparing the durability and lowtemperature environmental adaptability of power batteries and fuel cells, it is concluded that equipping largecapacity power batteries can reduce the operating time of fuel cells under adverse working conditions and improve lowtemperature cold start performance. Research on the braking energy recovery of fuel cell vehicles has found that increasing the power battery capacity can improve the regenerative braking recovery ability of the vehicle during longdistance slow braking. The analysis of the full lifecycle cost of fuel cell systems indicates that a reasonable match between power batteries and fuel cells can reduce system costs. Furthermore, it is pointed out that one of the important future development directions for fuel cell vehicles is plugin electrification, which provides some guidance for the commercial development of fuel cell vehicles.

The waterthermal management system of a fuel cell is the core system that maintains the waterthermal balance of fuel cell engines. Factors such as flow rate, temperature and pressure distribution have significant impacts on the performance, power consumption, and reliability of fuel cell engines. Based on a 120 kWrated fuel cell engine, a theoretical basis for architecture design and component selection matching was provided from the perspective of optimal system function and performance. According to relevant design inputs and objectives, the modeling, simulation, and result analysis of the waterthermal management system were carried out using the onedimensional simulation software FloMaster. The distribution of flow rate, pressure, temperature, and velocity in the system under different operating conditions was evaluated, and verified through bench testing. The simulation and experimental results show that key technical indicators, such as the water pump flow rate, the temperature difference between the inlet and outlet of the fuel cell stack, and the inlet temperature of the fuel cell stack meet the system's target requirements under both rated and idle operating conditions.

Temperature control is crucial for achieving rapid response, reducing energy consumption, and ensuring the safe operation of fuel cell engines. The coupling characteristics of the internal thermal field, electrochemical field, and flow field are key factors in temperature control. This article focuses on a mediumsized fuel cell truck, constructing a “heatelectricityflow” multifield model. It establishes key temperature control factors through parameter analysis, designs a fuzzy PID temperature controller, and verifies the control effectiveness under various operating conditions. The results show that the constructed model can comprehensively analyze the key parameters of temperature control. The proposed controller effectively improves response speed, reduces the speed of the cooling fan and decreases output voltage overshoot. Under both the set test condition and the NEDC condition, the temperature overshoot is reduced by 19.1% and 1.64% respectively. This work provides a foundation for the design and control of fuel cell engines, further promoting the invehicle application of highpower fuel cell engines.

In order to reduce the adverse effects of pressure fluctuations on the service life of fuel cells, the effectiveness of adding a bypass valve to control pressure fluctuations was investigated through simulation and comparative experiments. Based on the analysis of the fuel cell output characteristics and operating principles of each component, the mechanism and control model was established. An inverted decoupling method based on active disturbance rejection was used to achieve decoupling control of flow and pressure. Pressure fluctuation control was implemented using a fuzzy PI control. The effect of decoupling control within this system structure was verified using the Matlab/Simulink platform. The peak pressure fluctuation in the comparative experiments is 1.09 kPa with the bypass valve and 1.82 kPa without the bypass valve respectively. The addition of a bypass valve can reduce pressure fluctuations, thereby increasing the service life of the fuel cell.

For the control strategy of the vehicle fuel cell system, the paper summarizes the current research status and development trends in the aspects of system structure, control objects, control objectives and control methods. In terms of system structure design, the development of highperformance key components is essential to simplify the control system structure and to reduce control complexity. Concerning control objects, the decoupling control for strongly coupled physical quantities requires further indepth study. As for control objectives, multiobjective optimal control strategies will be the focus of future research. In regard to control methods, composite control strategies and intelligent control strategies based on learning will shape the future research trajectory.

To address the potential safety risks caused by hydrogen leakage from the onboard hydrogen system in confined spaces, a hydrogen leakage diffusion simulation study was carried out on a hydrogen fuel cell semitrailer tractor in a confined space using fluent software. The results show that, using the backward hydrogen leakage data as a baseline, the hydrogen concentration near the vent increases by an average of 42.38% after upward leakage and by 99.89% after forward leakage. Taking the hydrogen concentration data at a leak rate of 10 g/s as a benchmark, the hydrogen concentration near the vent increases by an average of 4.68% at a leak rate of 20 g/s and 127.73% at a leak rate of 90 g/s. Under certain conditions, increasing the vent area can reduce the hydrogen concentration in the confined space, but it is far less effective than using forced ventilation near the vent. After a prolonged period of hydrogen leakage, the hydrogen distribution throughout the confined space gradually reaches equilibrium. Therefore, hydrogen leakage should be promptly and effectively restricted.

The performance of the hydrogen power system is a critical factor in the design of fuel cell electric vehicles, as it includes the device's characteristics, control effectiveness, and energy management outcomes. This study investigated a typical hydrogen power system that uses a metal hydride (MH) hydrogen storage tank and a proton exchange membrane (PEM) fuel cell. The aim was to evaluate the thermal coupling effects of the MHPEM hydrogen power system through mathematical modeling and realworld traffic testing. First, a multiphysical field coupling model of the MHPEM hydrogen power system was proposed based on the structure of the thermal exchange system. Then, numerical simulations and experiments were conducted based on the operating conditions of a rangeextended fuel cell hybrid electric vehicle. The results indicated that the proposed mathematical model can accurately characterize the dynamic features of the onboard hydrogen energy system. The comparison of simulation and experimental results showed great agreement, particularly in terms of power response and temperature dynamics. Further analysis of the influence of atmospheric temperature on the hydrogen supply flow was carried out by examining the temperature variation in the MH tank. The results show that the thermal coupling design is an effective method for improving energy efficiency. The results of this study may be used for optimal sizing, temperature control, and energy management strategy design of MHPEM hydrogen power systems.

Focusing on the thermal management and waste heat recovery of a fuel cell bus, an integrated vehicle thermal manage system is developed, and 9 corresponding operation modes are proposed. A simulation mode is established based on AMESim to analyze the temperature control characteristics and energy consumption of the system under high, low and extremely low temperature conditions. The results show that under hightemperature conditions of 34, 37, 40 °C, the thermal manage system can maintain key components within an appropriate temperature range to meet their respective cooling requirements. Under lowtemperature conditions of 10, 5,0,5 °C, the thermal management system can meet the heating needs of the key components. Additionally, the waste heat from the fuel cell stack and motor can meet the cabin heating requirements when the ambient temperature is above 15 °C. This can save up to 10.44% of the vehicle's driving energy consumption compared to using pure PTC for cabin heating. Under extreme cold conditions of 30, 25, 20 °C, the waste heat alone is insufficient to meet the cabin heating demand, requiring the use of PTC for auxiliary heating. The additional equivalent hydrogen consumption for PTC heating is 44.10, 36.89, 33.5 g, respectively.

The aging process of a proton exchange membrane fuel cell (PEMFC) affects its output performance, and in order to accurately control output power, it is necessary to consider the aging and power degradation trends of the PEMFC. In this paper, the powercurrent curve is used as an indicator of the state of health (SOH). Based on previous studies, improvements have been made by considering changes in opencircuit voltage during the aging process. The number of aging factors in the aging model has been increased and the mapping relationship between the PEMFC power and the aging of the internal components is established. A semimechanical power degradation model is derived based on polarization curves, and an aging rate model has been designed using the particle filter algorithm. Combining the power decay analysis, the paper estimated the fuel cell's SOH. Simulations were carried out on the test dataset and compared with experimental test data. The results show that the method can predict the longterm performance decay model. Furthermore, compared with existing research methods, the proposed method estimates the SOH and performance decay trend of PEMFCs more accurately through the use of aging rate reference values and the power decay model. With reduced training time, there is an improvement in estimation accuracy. Especially when the training time is 100 hours and the estimation time is 250 hours, the error's relative decrease rate reaches 65.69%.

Supported by the dualcarbon goal and various new energy policies, the hydrogen energy industry has experienced rapid development. As the hub of upstream hydrogen production, midstream hydrogen storage and downstream application markets in the hydrogen energy industry, the construction and development of hydrogen refueling stations are inseparable from safety risk assessment. In this study, a quantitative risk assessment method for hydrogen refueling stations was established, and a quantitative risk assessment software Safeti was used to evaluate the risk of a hydrogen refueling station. Based on the individual risk contours and social risk analysis results, the accident risk level of the hydrogen refueling station was determined. Finally, to ensure the safety of hydrogen refueling stations, risk prevention and control measures are proposed from the aspects of standards, safety systems and institutional frameworks.