Due to the low efficiency and high pollution of conventional internal combustion engine vehicles, the fuel cell hybrid electric vehicles are expected to play a key role in the future of clean energy transportation attributed to the long driving range, short hydrogen refueling time and environmental advantages. The development of energy management strategies has an important impact on the economy and durability, but most strategies ignore the aging of fuel cells and the corresponding impact on hydrogen consumption. In this paper, a rule-based fuzzy control strategy is proposed based on the constructed data-driven online estimation model of fuel cell health. Then, a genetic algorithm is used to optimize this fuzzy controller, where the objective function is designed to consider both the economy and durability by combining the hydrogen consumption cost and the degradation cost characterized by the fuel cell health status. Considering that the rule-based strategy is more sensitive to operating conditions, this paper uses an artificial neural network for predictive control. The results are compared with those obtained from the genetic algorithm optimized fuzzy controller and are found to be very similar, where the prediction accuracy is assessed using MAPE, RMSE and 10-fold cross-validation. Experiments show that the developed strategy has a good generalization capability for variable driving cycles.

The endplate plays an important role in the performance and durability of fuel cell stacks, and also to mass power density. Aiming at a lightweight endplate and uniform deflection of the endplate, the purpose of this study is to model the endplate including the supply, discharge ports and the distribution manifolds. The stress and displacement distribution of the endplate are also analyzed by numerical simulation. After that, the three optimized topologies aiming to minimize compliance, uniform stress distribution and two objectives coupling are discussed, and the intake endplate and blind endplate are individually reconstructed. The mass of optimized intake endplate is reduced by 35%, and the mass of optimized blind endplate is reduced by 46% for the goal of attaining a lightweight endplate, while maintaining the uniformity of the stress distribution of the first cell next to the endplate. Considering these factors, optimized endplates are obtained, which are valuable to fuel cell stack design.

With the development of fuel cell vehicle technology, an effective testing method that can be applied to develop and verify the fuel cell vehicle powertrain system is urgently required. This paper presents the X-in-the-Loop (XiL) testing method in the fuel cell vehicle (FCV) hybrid degree test to resolve the first and key issues for the powertrain system design, and the test process and scenarios were designed. The hybrid degree is redefined into the static hybrid degree for system architecture design and the dynamic hybrid degree for vehicle control strategy design, and an integrated testing platform was introduced and a testing application was implemented by following the designed testing flowchart with two loops. Experimental validations show that the sizing of the FCE (Fuel Cell Engine), battery pack, and traction motor with the powertrain architecture can be determined, the control strategy can be evaluated seamlessly, and a systematic powertrain testing solution can be achieved through the whole development process. This research has developed a new testing platform and proposed a novel testing method on the fuel cell vehicle powertrain system, which will be a contribution to fuel cell vehicle technology and its industrialization.

By analyzing the three-dimensional digital model of a real carbon paper gas diffusion layer (GDL) reconstructed by X-ray computed tomography (CT), it was found that fibers are not distributed at any angle but within a certain range. The fiber orientation can be represented by fiber pitch (i.e., the angle between a single fiber and the in-plane direction). The effect of fiber orientation on stochastic reconstruction and transport properties (permeability) was investigated in this paper to find which fiber pitch range can achieve a better GDL on fluid flow. First, the actual fiber pitch was measured by analyzing SGL-24BA images obtained by X-ray CT. Also, seven different ranges of fiber pitch were randomly chosen to reconstruct GDL. Then, the permeability of these digital models was calculated using the Lattice Bolzmann Method (LBM) and discussed to obtain the fiber pitch range of the optimal permeability. The results show that the mean fiber pitch of SGL-24BA is 2.40° and the individual values are all less than 6°, also, the permeability of the through-plane direction increases gradually as the range of fiber pitch increases, which can be used for the structural design of carbon paper GDL.

The contact pressure between bipolar plates (BPPs) and a membrane electrode assembly (MEA) has a key impact on Proton Exchange Membrane Fuel Cell (PEMFC) performance. However, it is difficult to obtain the contact pressure combined with operating temperature action via the finite element analysis (FEA) model, resulting in limited calculation resources for the problem of multiscale and thermo-mechanical coupled action in a full-dimensional fuel cell stack. This paper establishes an equivalent stiffness model for contact pressure, which could be predicted simply and quickly compared with the FEA model. Then, this presented model is validated by experimentation with a full-dimensional fuel cell stack assembled with 10 cells using pressure-sensitive film. The error between the presented model and the experimentation of the full-dimensional stack is a maximum of 4.41%. This work provides important insight into thermo-mechanical coupled action, as less empirical testing is required to identify the contact pressure in a full-dimensional fuel cell stack.

Faced with key obstacles, such as the short driving range, long charging time, and limited volume allowance of battery-powered electric light scooters in Asian cities, the aim of this study is to present a passive fuel cell/battery hybrid system without DC-DC to ensure a compact volume and low cost. A novel topology structure of the passive fuel cell/battery power system for the electric light scooter is proposed, and the passive power system runs only on hydrogen. The power performance and efficiency of the passive power system are evaluated by a self-developed test bench before installation into the scooters. The results of this study reveal that the characteristics of stable power output, quick response, and the average efficiency are as high as 88% during the Shanghainese urban driving cycle and 89.5% during the Chinese standard driving cycle. The results present the possibility that this passive fuel cell/battery hybrid powertrain system without DC-DC is practical for commercial scooters.