Effects of reactants/coolant non-uniform inflow on the cold start performance of PEMFC stack

Wei, Lin; Dafalla, Ahmed Mohmed; Jiang, Fangming

doi:10.1016/j.ijhydene.2020.03.031

Cited by 36 publications

(8 citation statements)

References 45 publications

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“…The essence of fuel cell cold start is the competition between the heat generation and freezing process during the startup process from ambient temperature to normal working temperature of the fuel cell . Specifically, the heat generated by the reaction increases the temperature of the fuel cell, and the presence of water below zero freezing characteristics may block the effective reaction sites in the catalytic layer (CL) and the gas–liquid transport path in the gas diffusion layer (GDL), slowing down the reaction rate . Failure of cold start will cause damage to the key components, which seriously affects the durability and performance of fuel cell. − In the study of the electrochemical and thermodynamic behavior of the PEMFC cold start process, the advantage of visualization experiments is the ability to directly observe the component distribution and test the cell performance.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Ice Melting Process in a Simplified Gas Diffusion Layer of Fuel Cell by the Lattice Boltzmann Method

Jiang

Yang

et al. 2022

Energy Fuels

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Cold start is a challenge for the proton exchange membrane fuel cell, and understanding the heat transfer characteristics of solid–liquid phase change in this process is necessary. An enthalpy-based lattice Boltzmann model is established, and the heat transfer of ice melting in in-plane and through-plane of the gas diffusion layer (GDL) is studied. The effects of fiber diameter, double heat sources, and Rayleigh number are analyzed. It is found that the fiber diameter has a significant influence on heat transfer. The ice melting rate of XZ position is faster than other planes, and it has the best effect when the diameter is 8 μm. The heat transfer of different heating positions is analyzed, and it is found that the left-right-heated has the highest melting efficiency. The heat sources location has different effects on the heat transfer between the XY position (TP1) and YZ position (TP2). Although the increase of Rayleigh number can enhance the convective heat transfer, the change of melting efficiency is extremely small. The convective heat transfer intensity has no direct effect on the ice melting of GDL, and fiber plays a more critical role in the heat transfer of ice melting.

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Section: Introductionmentioning

confidence: 99%

Investigation of the Ice Melting Process in a Simplified Gas Diffusion Layer of Fuel Cell by the Lattice Boltzmann Method

Jiang

Yang

et al. 2022

Energy Fuels

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“…Nevertheless, a high flow rate or low coolant tank capacity provided a more uniform temperature distribution. In the second research, initial non‐uniform water content was found to be a considerable specification and it was stated that the cold start ability developed with a higher cathode stoichiometry ratio 54 . Numerical assisted heating strategies were evaluated by Yang et al 55 They implemented an integrated transient system model and managed a successful unassisted operation at −10°C while failing at −20°C.…”

Section: Introductionmentioning

confidence: 99%

The effect of the heater and the pump operation durations on the cold start performance of the coolant heating assisted PEM fuel cell application

Topcu

Aydın

Çelik

2022

Intl J of Energy Research

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Summary The self‐cold start ability of the proton exchange membrane (PEM) fuel cell system is limited due to the inadequate heat generation by the cell and the restricted effect of operating conditions. Fresh and useful heat may be provided by an external assisted technique that is adopted in the current study. The operation duration effect of the pump and the heater which are the most energy‐consuming components of the coolant heating assisted method on the cold start performance of a PEM fuel cell stack was investigated, experimentally. Firstly, the inadequacy of the single‐cell operation was proved by self‐operation tests. The test was conducted at −10°C and the temperature was raised to −7.5°C levels during the test thanks to exothermic reactions that occurred in the cell. It manifests the cell may not be survived without any assistance and an external heat source is required. This fresh heat was supplied to the cell by the closed coolant cycle. Ethanol which can be operated at subzero temperatures was circulated throughout the machined external channels to the backside of the bipolar plates. The case studies were established considering various operation durations of the pump and the heater and the cold start tests were performed at −10°C, −15°C, −20°C, −25°C, and −30°C temperatures. The effect of the pump and the heater operation durations on the temperature, voltage, and current profiles of the single‐cell were investigated under the same energy consumption levels. The cell was operated throughout the whole case study and generated electricity successfully. It put forward the accomplishment of the proposed heating mechanism even at −30°C. The time required for the cell temperature to rise above zero is increase with the decrease of the cold start test temperature. The cell temperature increased to zero at approximately 18, 39, and 53 seconds at −10°C, −20°C, and −30°C operations, respectively. The PEM fuel cell stack, which does have not the capacity to operate itself at sub‐zero temperatures, was successfully operated with the help of the established mechanism. No higher starter energy is needed for a −10°C operation and the cell may be survived with a low operation of the auxiliary equipment. Failed starts were experienced with long heater and low pump cases at −20°C and −25°C temperatures. It is thought that a sharp drop in temperature after a pump shutdown prompts the cell into an unstable situation and fluctuations in voltage and current profiles. Although failed starts were recorded with implemented case studies at −30°C at the initial stage, successful cold starts were achieved by the extended durations of the pump and heater, proportionally 2.6 and 5.5 A stable current, and 23.7°C and 20°C maximum temperature values were obtained with long heater operation and long pump operation cases, respectively. Although long heater operation provided a higher temperature increase, the long pump operation enabled a more homogeneous temperature distribution and stable current profile. This study revealed the st...

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“…More detailed description of transport phenomena during cold start processes of PEMFC stacks were presented based on multidimensional models to explore the multifield coupling mechanism inside cells. [27,30,[34][35][36][37] By comparing the cold-start behaviors of end cell and middle cell, Chippar and Ju [34] found that the end cell bundled with endplate shows plenty of ice in cathode CL, as a result, it failed to start up. Luo et al [35] further developed a stack model based on the single cell model of Jiao and Li.…”

Section: Introductionmentioning

confidence: 99%

“…Their results demonstrated that by lowering the cathode stoichiometry, the vapor diffusion is enhanced, which can contribute to reducing ice accumulation in the cathode CL. The cooling channel (CC) and coolant circulation were included in the cold start model developed by Wei et al [37] It was found that the nonuniform inflow of reactant and coolant between different channels has an important impact on temperature and ice distributions. Using a spatial resolution method, Tang et al [38] simulated the cold start process of stack with 400 cells using rapid warm-up operation with low cell voltage and stoichiometry, which was proved to be an effective way to quickly elevate the stack temperature from À20 to 5 C within 30 s.…”

Section: Introductionmentioning

confidence: 99%

Effects of Endplate Assembly on Cold Start Performance of Proton Exchange Membrane Fuel Cell Stacks

et al. 2021

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Effects of reactants/coolant non-uniform inflow on the cold start performance of PEMFC stack

Cited by 36 publications

References 45 publications

Investigation of the Ice Melting Process in a Simplified Gas Diffusion Layer of Fuel Cell by the Lattice Boltzmann Method

Investigation of the Ice Melting Process in a Simplified Gas Diffusion Layer of Fuel Cell by the Lattice Boltzmann Method

The effect of the heater and the pump operation durations on the cold start performance of the coolant heating assisted PEM fuel cell application

Effects of Endplate Assembly on Cold Start Performance of Proton Exchange Membrane Fuel Cell Stacks

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