The cold start property is one of the main factors restricting the fuel cell application in the automotive field. The constant voltage cold start method of the fuel cell works under low start voltage and produces high heat, which can shorten the start-up time of the fuel cell at low temperature and has the opportunity to be applied to fuel cell vehicles. Meanwhile, in the constant voltage cold start mode, the fuel cell needs to operate under a large current, and more water is generated during the start-up process. Thus, the optimization of operating conditions for the constant voltage cold start is particularly important. However, there are relatively few studies on the optimization of operating conditions for the constant voltage cold start with a single-cell voltage less than 0.3 V. In this work, the cold start experiment of the fuel cell with constant voltage is carried out. According to the cold start experiment, the different cold start voltage, back-pressure, and the inlet flow rate are examined. Based on the experiment data, the operating conditions have a great influence on the cold start property of the fuel cell and the optimized operating conditions of the constant voltage cold start are obtained.

The proton exchange membrane fuel cell (PEMFC) is taken to be the ultimate technical direction of vehicle power. Cooling system is a key component which directly affects the fuel cell performance, reliability and durability. For the purpose of keeping accurate temperature control under dynamic loads and achieving rapid warm-up control during cold-start, a 35 kW PEMFC’s cooling system dynamic model is established and validated by experiments firstly. According to the simulation results, the model can well be fitted to the actual system. Then an integrate separate PID (Proportional-Integral-Derivative) algorithm and cooling fan prestart strategy is proposed. The result shows that it can effectively reduce the temperature overshoot under dynamic loads. In view of the thermostat mechanical characteristics tend to cause large temperature fluctuation during warm-up process, a thermostat control strategy is proposed to reduce the temperature fluctuation from 7.5 °C to 0.4 °C.

For commercial applications, the durability and economy of the fuel cell hybrid system have become obstacles to be overcome, which are not only affected by the performance of core materials and components, but also closely related to the energy management strategy (EMS). This paper takes the 7.9 t fuel cell logistics vehicle as the research object, and designed the EMS from two levels of qualitative and quantitative analysis, which are the composite fuzzy control strategy optimized by genetic algorithm and Pontryagin’s minimum principle (PMP) optimized by objective function, respectively. The cost function was constructed and used as the optimization objective to prolong the life of the power system as much as possible on the premise of ensuring the fuel economy. The results indicate that the optimized PMP showed a comprehensive optimal performance, the hydrogen consumption was 3.481 kg/100 km, and the cost was 13.042 $/h. The major contribution lies in that this paper presents a method to evaluate the effect of different strategies on vehicle performance including fuel economy and durability of the fuel cell and battery. The comparison between the two totally different strategies helps to find a better and effective solution to reduce the lifetime cost.

Reliability and durability are the main factors that hinder the large-scale commercialization of proton exchange membrane fuel cell (PEMFC). Water management is the key to solve such problems, and water content is the measurement standard of water management. But it is very difficult to measure water content inside the fuel cell directly. Thus, water fault diagnosis is a basic technology to monitor the water content indirectly based on the measurable parameters. In this paper, the water fault diagnosis of the PEMFC system has been summarized in three sections including the theoretical model-based method, knowledge-based method, and signal processing method from practical application, and part of them is from the perspective of vehicle application.