scholarly journals Investigation on the Operating Conditions of Proton Exchange Membrane Fuel Cell Based on Constant Voltage Cold Start Mode

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 660
Author(s):  
Yanbo Yang ◽  
Tiancai Ma ◽  
Boyu Du ◽  
Weikang Lin ◽  
Naiyuan Yao

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.

Author(s):  
Yanbo Yang ◽  
Tiancai Ma ◽  
Fenglai Pei ◽  
Weikang Lin ◽  
Kai Wang ◽  
...  

Abstract The constant voltage cold start of the proton exchange membrane fuel cell (PEMFC) is usually operated at a low start voltage in order to ensure high heat generation, which can shorten the process of the PEMFC cold start. However, the effect of constant voltage cold start on the durability of PEMFC is still unclear. Thus, in this work, the PEMFC is tested repeatedly at a low start-voltage to simulate its actual operating state in the vehicle. Then the effect of the PEMFC durability under constant voltage cold start is investigated by polarization curve, cyclic voltammetry, electrochemical impedance spectroscopy, transmission electron microscope and ion chromatography. After the repeatedly cold start, the output performance of the PEMFC decreases significantly. According to the characterization results, the degradation mechanism of the PEMFC at the constant voltage cold start is demonstrated to be that the PEMFC start-up repeatedly at low start-voltage leads to the decomposition of membrane polymer structure and promotes the crossover of H2. Meanwhile, the PEMFC start-up repeatedly at low start-voltage also leads to the agglomeration of catalysts, which reduces the active area of catalysts and ultimately results in the degradation of fuel cell performance. Above all, this study proves that the durability of PEMFC can be shortened by the constant voltage cold start at 0.1 V, which provides a reference for the development of the PEMFC cold start control strategy.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4456
Author(s):  
Wei Jiang ◽  
Ke Song ◽  
Bailin Zheng ◽  
Yongchuan Xu ◽  
Ruoshi Fang

In order to realize the low temperature and rapid cold start-up of a proton exchange membrane fuel cell stack, a dynamic model containing 40 single proton exchange membrane fuel cells is established to estimate the melting time of the proton exchange membrane fuel cell stack as well as to analyze the melting process of the ice by using the obtained liquid–solid boundary. The methods of proton exchange membrane electric heating and electrothermal film heating are utilized to achieve cold start-up of the proton exchange membrane fuel cell (PEMFC). The fluid simulation software fluent is used to simulate and analyze the process of melting ice. The solidification and melting model and multi-phase flow model are introduced. The pressure-implicit with splitting of operators algorithm is also adopted. The results show that both the proton exchange membrane electric heating technology and the electrothermal film heating method can achieve rapid cold start-up. The interior ice of the proton exchange membrane fuel cell stack melts first, while the first and 40th pieces melt afterwards. The ice melting time of the proton exchange membrane fuel cell stack is 32.5 s and 36.5 s with the two methods, respectively. In the end, the effect of different electrothermal film structures on cold start-up performance is studied, and three types of pore diameter electrothermal films are established. It is found that the electrothermal film with small holes melts completely first, and the electrothermal film with large holes melts completely last.


Author(s):  
Satish G. Kandlikar ◽  
Zijie Lu

Each fuel cell component of a proton exchange membrane fuel cell (PEMFC) used in automotive application operates most effectively (from performance and durability standpoints) within specific ranges of water content and temperature. The water and heat transport processes are coupled and present a challenge in providing the right balance over the entire range of operating conditions. Another important related aspect is CO poisoning of the electrocatalyst, which adversely affects the fuel cell performance. Freezing and cold-start present additional challenges for automotive PEMFCs. A critical review of the recent developments on these topics is presented in this paper. The study covers both the microscopic and macroscopic aspects of the transport within membrane, catalyst layers, gas diffusion layers, and gas channels, and an overview of the current PEMFC cooling technology. After discussing the current status, suggestions for future work on the above topics are presented.


Author(s):  
Taehee Han ◽  
Tessa A. Haagenson ◽  
Hossein Salehfar ◽  
Samir Dahal ◽  
Mike D. Mann

In this study, an efficient method of approximating individual fuel cell impedances in a stack is proposed and experimentally verified. Two different proton exchange membrane (PEM) fuel cell stacks (600 W with 24 cells and 1.2 kW with 47 cells) were used to develop and verify the method. Both PEM fuel cell stacks were operated using room air and pure hydrogen (99.999%). Impedance and current - voltage (I-V) data were collected for stack and individual cell levels under various operating conditions. The experimental result shows that the individual cell impedance is directly proportional to the corresponding cell voltage. Therefore individual cell impedance can be accurately estimated by performing only stack impedance and individual cell voltage measurements.


Energy ◽  
2021 ◽  
Vol 222 ◽  
pp. 119910
Author(s):  
Zirong Yang ◽  
Kui Jiao ◽  
Kangcheng Wu ◽  
Weilong Shi ◽  
Shangfeng Jiang ◽  
...  

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