Article
Thermodynamics
Mengzhu Luo, Jun Zhang, Caizhi Zhang, Cheng Siong Chin, Hongxu Ran, Min Fan, Kun Du, Qi Shuai
Summary: The cold start strategy of coolant preheating is crucial and feasible, but the preheating time needs to be shortened. In low temperature environments, attention should be paid to the fluctuation of fuel cell output power and the deterioration of voltage uniformity.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Ahmed Mohmed Dafalla, Lin Wei, Zihao Liao, Jian Guo, Fangming Jiang
Summary: This study develops a model to investigate the influence of adding blockages in the cathode gas channels on the cold start performance of PEMFC. The simulation results show that the addition of blockages helps to mitigate the oxygen transport limitation, resulting in better cold start performance.
Article
Chemistry, Multidisciplinary
Jinqiao Liang, Linhao Fan, Qing Du, Yan Yin, Kui Jiao
Summary: In this study, comprehensive in situ non-accelerated segmented techniques are developed to analyze the degradation mechanisms of PEM fuel cells during cold start at sub-freezing temperatures. A detailed degradation mechanism map is proposed to understand the degradation under different conditions and suppress ice formation. An ideal starting strategy is also developed to achieve cold start without degradation. This study is highly valuable for researchers to understand degradation mechanisms and promote the commercialization of PEM fuel cells.
Article
Engineering, Environmental
Xiaokang Yang, Jiaqi Sun, Xiangchao Meng, Shucheng Sun, Zhigang Shao
Summary: This study investigates the degradation mechanism of cold start in proton exchange membrane fuel cells (PEMFCs). It analyzes the degradation behavior through segmented print circuit board technology and local characterizations, and finds that cell performance and current density distribution are severely degraded after 30 cold start failures. The research also reveals that freezing-induced crack formation, Pt particle growth, and ionomer agglomeration are the root causes of freezing damage during cold start.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Xiaokang Yang, Jiaqi Sun, Shucheng Sun, Zhigang Shao
Summary: This paper proposes an efficient cold start strategy for PEMFC stacks, which combines the advantages of self-starting and coolant heating, and is validated in terms of startup time, voltage consistency, and energy consumption.
JOURNAL OF POWER SOURCES
(2022)
Article
Thermodynamics
Zihao Liao, Lin Wei, Ahmed Mohmed Dafalla, Zhenbang Suo, Fangming Jiang
Summary: Cold starting a PEMFC engine in sub-freezing temperatures presents technical challenges, with intra-electrode ice formation being a major concern. A study on PEMFCs with zigzag-channeled flow field (ZZFF) found that ZZFF enhances reactant/product distribution and current density, improving survivability but slightly degrading quick self-startup ability. Further research validates the effects of ZZFF configuration on PEMFC cold start performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Physical
Peng Wang, Linjun Li
Summary: The cold start performance of proton-exchange membrane fuel cells (PEMFCs) can be enhanced by creating penetrating holes in the cathode micro-diffusion layer (MDL). Experimental results showed that the 0.5-mm-diameter penetrating holes significantly improved the water permeance of the MDL by three orders of magnitude. The fuel cell using the MDL with 0.2-mm-diameter penetrating holes performed the best in regular operation at 70 degrees C and in cold starts from -7 degrees C.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Electrochemistry
Haosen Xu, Shangshang Wang, Dechun Si, Jianbo Zhang
Summary: Cold start is a challenge for the diffusion of fuel cell vehicles in cold regions. The alternating hydrogen pump (AHP) method provides a fast, efficient, and reliable startup without concerns of freezing. However, puzzling phenomena related to current variation and high frequency resistance (HFR) change are observed during the AHP under constant voltage mode. These phenomena, which affect the efficiency and speed of cold starts, are not well understood. In this study, a one-dimensional transient model is developed to explain these phenomena and has the potential for optimizing the cold start process.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Kefeng Hu, Tiankuo Chu, Fan Li, Baoyun Wang, Zhihui Zhang, Tanda Liu
Summary: The study focused on optimizing strategies to achieve rapid cold start-up of a 30-cell stack under extreme low temperature conditions. Experimental results showed that the control strategies effectively prevented irreversible damage to the stack during freeze-thaw processes.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Xiaokang Yang, Xiangchao Meng, Jiaqi Sun, Wei Song, Shucheng Sun, Zhigang Shao
Summary: This study investigates the internal dynamics and transient phenomena during the cold start of a proton exchange membrane fuel cell (PEMFC) using segmented fuel cell technology. It is found that the flow field has a lesser impact on cold start performance compared to normal temperature operation. The single-channeled serpentine (SS) flow field exhibits the fastest response rate and better cold start performance due to its high pressure drop and excellent drainage ability.
JOURNAL OF POWER SOURCES
(2023)
Article
Thermodynamics
Mingzhang Pan, Ding Li, Chengjie Pan, Lu Liang
Summary: This study proposes a novel adaptive cold-start strategy based on maximum power tracking for proton exchange membrane fuel cells, optimizing the cold-start effect by improving the output voltage model and multi-parameter evaluation model.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Energy & Fuels
Lin Wei, Zihao Liao, Ahmed Mohmed Dafalla, Zhenbang Suo, Fangming Jiang
Summary: The endplate assemblies (EAs) of a proton exchange membrane fuel cell (PEMFC) stack are crucial for stabilizing the structure and distributing preload evenly. A 3D multidisciplinary transient model was established to evaluate the impact of EAs on the cold start performance of PEMFC stacks. EAs significantly affect temperature and ice distributions in the end cell, particularly in reducing water diffusivity and leading to ice accumulation in the cathode catalyst layer.
Article
Chemistry, Physical
Like Yue, Shixue Wang, Yu Zhu, Yue Fan
Summary: Experimental methods were used to study the effect of assembly torque and channel size on cold start performance. It was found that an assembly torque of 2 N·m resulted in better cold start performance, and a channel width of 0.5 mm and depth of 0.3 mm led to the best cold start performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Sitong Chen, Shubo Wang, Xueke Wang, Weiwei Li, Baorui Liang, Tong Zhu, Xiaofeng Xie
Summary: Adding microencapsulated phase change materials (MPCMs) to antifreeze fluid improves heat transfer capability and solves the cold start problem of PEMFC.
Article
Energy & Fuels
Yanbo Yang, Tiancai Ma, Boyu Du, Weikang Lin, Naiyuan Yao
Summary: The optimization of operating conditions for constant voltage cold start is crucial in improving the cold start property of fuel cells. Experimental results show that different cold start voltage, back-pressure, and inlet flow rate have significant impacts on the cold start performance of fuel cells, and optimizing the operating conditions can achieve the optimized constant voltage cold start conditions.
Review
Chemistry, Physical
Ahmed Mohmed Dafalla, Fangming Jiang
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2018)
Article
Electrochemistry
A. M. Dafalla, L. Wei, Z. H. Liao, F. M. Jiang
Article
Thermodynamics
Zihao Liao, Lin Wei, Ahmed Mohmed Dafalla, Zhenbang Suo, Fangming Jiang
Summary: Cold starting a PEMFC engine in sub-freezing temperatures presents technical challenges, with intra-electrode ice formation being a major concern. A study on PEMFCs with zigzag-channeled flow field (ZZFF) found that ZZFF enhances reactant/product distribution and current density, improving survivability but slightly degrading quick self-startup ability. Further research validates the effects of ZZFF configuration on PEMFC cold start performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Ahmed Mohmed Dafalla, Fangming Jiang
Summary: Water transport plays a vital role in the cold start of proton exchange membrane fuel cells (PEMFCs). The mesoscopic morphology of the cathode catalyst layer (CCL) significantly affects the performance of PEMFC cold start, with less tortuous pore structure leading to successful cold-starting. Innovative preparation methods for catalyst layers with larger primary pores and less tortuous structures are desired for improved cold start performance.
FRONTIERS IN ENERGY
(2021)
Article
Thermodynamics
Zihao Liao, Lin Wei, Ahmed Mohmed Dafalla, Jian Guo, Fangming Jiang
Summary: The flow field configuration of a PEMFC is crucial for performance enhancement, and the study found that the contrary arrangement design provides more uniform distributions of reactants and reaction products compared to traditional designs. Additionally, the contrary arrangement design reduces mass transport resistance and boosts heat/mass transfer rates, especially under higher relative humidity and larger operating pressure conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Lin Wei, Zihao Liao, Ahmed Mohmed Dafalla, Fangming Jiang
Summary: This study presents a new fuel cell flow field with 3 pi/2 radian Dean flow channels and investigates its impact on the performance of proton exchange membrane fuel cells. The results show that the unstable vortices formed in the Dean flow channels enhance mass transfer, leading to improved performance under high current density. It is also found that the oxygen transport enhancement with the Dean channel is more significant at relatively small cathode stoichiometry. Additionally, by reducing the gas diffusion layer porosity, the membrane can be kept at high humidity, resulting in improved power output and stability of the fuel cell under low cathode inlet pressure operation.
Review
Energy & Fuels
Ahmed Mohmed Dafalla, Lin Wei, Bereket Tsegai Habte, Jian Guo, Fangming Jiang
Summary: This paper discusses the degradation mechanisms in proton exchange membrane fuel cells (PEMFCs), specifically in the membrane electrode assembly (MEA), and presents different numerical modeling approaches to address these issues.
Article
Thermodynamics
Ahmed Mohmed Dafalla, Lin Wei, Zihao Liao, Jian Guo, Fangming Jiang
Summary: This study develops a model to investigate the influence of adding blockages in the cathode gas channels on the cold start performance of PEMFC. The simulation results show that the addition of blockages helps to mitigate the oxygen transport limitation, resulting in better cold start performance.
Article
Thermodynamics
Lin Wei, Ahmed Mohmed Dafalla, Zihao Liao, Jian Guo, Xianwei Ai, Fangming Jiang
Summary: In this study, the air flow field design of air-cooled PEMFCs is compared and optimized. It is revealed that increasing the channel depth improves PEMFC performance under high current load conditions. The effectiveness of utilizing the zigzag flow channel is also assessed, and the best cell performance is obtained with a tilt angle of 2.5 degrees.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2023)