Dynamic characteristics of internal current during startups/shutdowns in proton exchange membrane fuel cells

Fei Jia, Liejin Guo, Hongtan Liu

Research output: Contribution to journalArticle

Abstract

Studying dynamic characteristics of proton exchange membrane fuel cells (PEMFCs) during startups/shutdowns is of great importance to proposing strategies to improve fuel cell performance and durability. In this study, internal current during startup and shutdown processes in PEMFC is investigated, and effects of gas supply/shutoff sequences and backpressure are analyzed by measuring local current densities and the cell voltage in situ. The experimental results show that when reactants were fed/shut off, internal current occurs and variation patterns of local current densities along the flow channel are different. During startups, local current densities in the downstream drop to negative values and internal current can be eliminated when air is first supplied into the cell. While during shutdowns, the results show that negative currents occur in the upstream, and if hydrogen is shut off first, all local current densities remain constant at zero, indicating the effectiveness of gas shutoff sequence in eliminating/mitigating internal current in PEM fuel cells. Further experimental results show that the magnitude of internal current increases with the pressure difference between the anode and the cathode.

Original languageEnglish (US)
JournalInternational Journal of Energy Research
DOIs
StatePublished - Jan 1 2019

Fingerprint

Proton exchange membrane fuel cells (PEMFC)
Current density
Fuel cells
Gas supply
Channel flow
Anodes
Durability
Cathodes
Hydrogen
Electric potential
Air
Gases

Keywords

  • internal current
  • local current density
  • proton exchange membrane fuel cell (PEMFC)
  • startup and shutdown

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology

Cite this

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title = "Dynamic characteristics of internal current during startups/shutdowns in proton exchange membrane fuel cells",
abstract = "Studying dynamic characteristics of proton exchange membrane fuel cells (PEMFCs) during startups/shutdowns is of great importance to proposing strategies to improve fuel cell performance and durability. In this study, internal current during startup and shutdown processes in PEMFC is investigated, and effects of gas supply/shutoff sequences and backpressure are analyzed by measuring local current densities and the cell voltage in situ. The experimental results show that when reactants were fed/shut off, internal current occurs and variation patterns of local current densities along the flow channel are different. During startups, local current densities in the downstream drop to negative values and internal current can be eliminated when air is first supplied into the cell. While during shutdowns, the results show that negative currents occur in the upstream, and if hydrogen is shut off first, all local current densities remain constant at zero, indicating the effectiveness of gas shutoff sequence in eliminating/mitigating internal current in PEM fuel cells. Further experimental results show that the magnitude of internal current increases with the pressure difference between the anode and the cathode.",
keywords = "internal current, local current density, proton exchange membrane fuel cell (PEMFC), startup and shutdown",
author = "Fei Jia and Liejin Guo and Hongtan Liu",
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AU - Guo, Liejin

AU - Liu, Hongtan

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Y1 - 2019/1/1

N2 - Studying dynamic characteristics of proton exchange membrane fuel cells (PEMFCs) during startups/shutdowns is of great importance to proposing strategies to improve fuel cell performance and durability. In this study, internal current during startup and shutdown processes in PEMFC is investigated, and effects of gas supply/shutoff sequences and backpressure are analyzed by measuring local current densities and the cell voltage in situ. The experimental results show that when reactants were fed/shut off, internal current occurs and variation patterns of local current densities along the flow channel are different. During startups, local current densities in the downstream drop to negative values and internal current can be eliminated when air is first supplied into the cell. While during shutdowns, the results show that negative currents occur in the upstream, and if hydrogen is shut off first, all local current densities remain constant at zero, indicating the effectiveness of gas shutoff sequence in eliminating/mitigating internal current in PEM fuel cells. Further experimental results show that the magnitude of internal current increases with the pressure difference between the anode and the cathode.

AB - Studying dynamic characteristics of proton exchange membrane fuel cells (PEMFCs) during startups/shutdowns is of great importance to proposing strategies to improve fuel cell performance and durability. In this study, internal current during startup and shutdown processes in PEMFC is investigated, and effects of gas supply/shutoff sequences and backpressure are analyzed by measuring local current densities and the cell voltage in situ. The experimental results show that when reactants were fed/shut off, internal current occurs and variation patterns of local current densities along the flow channel are different. During startups, local current densities in the downstream drop to negative values and internal current can be eliminated when air is first supplied into the cell. While during shutdowns, the results show that negative currents occur in the upstream, and if hydrogen is shut off first, all local current densities remain constant at zero, indicating the effectiveness of gas shutoff sequence in eliminating/mitigating internal current in PEM fuel cells. Further experimental results show that the magnitude of internal current increases with the pressure difference between the anode and the cathode.

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