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 paper reviews the formation mechanisms and detection methods of flooding and drying faults in proton exchange membrane fuel cells (PEMFCs). Firstly, the causes of flooding and drying faults are analyzed from the perspectives of structure, internal gas transport mechanism and water transport mechanism. Then, the fault detection methods based on modeling, datadriven approaches and direct imaging visualization are comprehensively investigated, and the technical characteristics of these diagnostic methods are deeply analyzed. Finally, considering the limitations and shortcomings of various diagnostic methods, the future improvement and development directions for diagnosing flooding and drying faults in PEMFCs are discussed. This includes utilizing technologies such as miniaturization and portability of electrochemical impedance spectroscopy (EIS) analysis equipment, improving battery model parameters and sharing battery fault big data.

The threedimensional form of the metal foam flow field is established. Through threedimensional numerical simulation, the results show that the metal foam flow field can effectively reduce the concentration polarization loss, thereby improving the performance of the fuel cell at high current densities. The increase in output power density is significant, while the corresponding pumping power loss is negligible. Furthermore, under the influence of the metal foam flow field, the oxygen concentration distribution inside the PEMFC is more uniform than that in the traditional straightchannel fuel cells. Bench experiments were conducted to observe the flow state of liquid water in the foam flow field and similar flow phenomenon was obtained through threedimensional numerical simulations. Compared with the traditional straightchannel designs,

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%.

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.

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.

To effectively control the thermal management system of a dualstack fuel cell system, this paper establishes a fuel cell stack model based on test data, and couples it with key component models such as pumps and heat exchangers to form a complete thermal management system model. To stabilize the stack temperature under disturbances, a control strategy combining proportionalintegral (PI) with linear active disturbance rejection control (LADRC) was proposed and verified by simulation. Finally, an improved control strategy based on feedforward decoupling and cascade LADRC was proposed. The control effects before and after the improvement were compared through simulation. The results show that the improved control strategy can effectively reduce overshoot, and the integral time absolute error (ITAE), reflecting temperature control accuracy, can be reduced by up to 66.39%.

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.

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.