Water distribution in high temperature polymer electrolyte fuel cells

Reimer, Uwe; Ehlert, Jannik; Janssen, Hans-Karl; Lehnert, Werner

doi:10.1016/j.ijhydene.2015.11.106

Cited by 36 publications

(32 citation statements)

References 60 publications

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“…Redistribution subject to ECS terms of use (see 192.38.90. 17 Downloaded on 2018-08-28 to IP Table I acid solution should give a lower viscosity to the system, resulting in a higher mobility of all particles within the system. 37 In addition, the hydrolysis of higher polymeric phosphoric acid will also lower the viscosity of the overall phosphoric acid.…”

Section: Modeling Results For Acid Migration and Back Diffusion-in Or-mentioning

confidence: 99%

“…Redistribution subject to ECS terms of use (see 192.38.90. 17 Downloaded on 2018-08-28 to IP of 0.17 atm. Current was supplied to the cell via an external constant current tester (Elcanic) capable of providing current from 0.1 to 10 A. Polarization curve recording of the hydrogen pump cell was done by stepwise increase of current within a range of 0 to 900 mA cm −2 .…”

Section: Methodsmentioning

confidence: 99%

“…Redistribution subject to ECS terms of use (see 192.38.90. 17 Downloaded on 2018-08-28 to IP gradient is defined as the difference between C anode and C cathode across the thickness of the diffusing layer z, as to be further discussed below. The diffusion coefficient D is obtained from the time dependent restoration of the specific ohmic resistance after the cell current is shut down.…”

Section: Modeling Hypothesis and Assumptionsmentioning

confidence: 99%

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Determination of Anion Transference Number and Phosphoric Acid Diffusion Coefficient in High Temperature Polymer Electrolyte Membranes

Becker

Reimer

Aili

et al. 2018

J. Electrochem. Soc.

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The passage of an electrical current through phosphoric acid doped polymer membranes involves parasitic migration of the acid, which imposes a critical issue for long-term operation of the high temperature polymer electrolyte membranes fuel cell (HT-PEMFC). To elucidate the phenomenon, a three-layered membrane is constructed with embedded micro reference electrodes to measure phosphoric acid redistribution in a polybenzimidazole based membrane. Under a constant load, a concentration gradient develops due to the acid migration, which drives the back diffusion of the acid and eventually reaches a steady state between migration and diffusion. The acid gradient is measured as a difference in local ohmic resistances of the anode-and cathode-layer membranes by electrochemical impedance spectroscopy. The phosphoric acid diffusion coefficient through the acid doped membrane is about 10 −11 m 2 s −1 , at least one order of magnitude lower than that of aqueous phosphoric acid solutions. The anion (H 2 PO 4 − ) transference number is found to range up to 4% depending on current density, temperature and atmospheric humidity of the cell, implying that careful control of the operating parameters is needed in order to suppress the vehicular proton conduction as a degradation mitigation strategy.

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Section: Modeling Results For Acid Migration and Back Diffusion-in Or-mentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Modeling Hypothesis and Assumptionsmentioning

confidence: 99%

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Determination of Anion Transference Number and Phosphoric Acid Diffusion Coefficient in High Temperature Polymer Electrolyte Membranes

Becker

Reimer

Aili

et al. 2018

J. Electrochem. Soc.

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“…Some studies [14][15][16][17][18][19][20][21][22][23][24][25][26] have investigated PEFC operated under elevated temperature than usual. Although the dynamic power generation characteristics [14][15][16][17][18][19], the degradation test [20][21][22], the water distribution [23], the power generation performance under different temperatures, relative humidity, gas flow rate and pressure [24,25] have been investigated, there have been a few reports [26,27] on temperature distribution in the cell of PEFC. Especially, the temperature distribution on "reaction surface" has not been investigated yet, except in our former study [28] using the proposed heat transfer model.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Temperature Distributions in Single Cell of Polymer Electrolyte Fuel Cell when Operated in Elevated Temperature Range

Nishimura¹,

Zamami²,

Yoshimura³

et al. 2017

JEPE

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Abstract:The purpose of this study is to analyze the temperature distribution on the interface between the polymer electrolyte membrane and catalyst layer at the cathode in single cell of polymer electrolyte fuel cell when operated in elevated temperature range than usual. In this study, the interface between the polymer electrolyte membrane and catalyst layer at the cathode is named as reaction surface. This study has considered the 1D multi-plate heat transfer model estimating the temperature distribution on the reaction surface and verified with the 3D numerical simulation model solving many governing equations on the coupling phenomena of the polymer electrolyte fuel cell. The 3D numerical simulation model coverers a half size of actual cell including three straight parts and two turn-back corners, which can display the essential phenomena of single cell. The results from both models/simulations agreed well. The effects of initial operation temperature, flow rate, and relative humidity of supply gas on temperature distribution on the reaction surface have been investigated. Though the effect of flow rate of supply gas on temperature distribution on reaction surface has been small, low relative humidity of supply gas has caused higher temperature on the reaction surface compared to high relative humidity of the supply gas. The temperature rise of reaction surface from initial operation temperature has increased with the increasing in initial operation temperature of cell.

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“…Some researches reported that the characteristics of PEFC under high temperature range up to 200 °C [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. However, most of them focused on characteristics of developed new material [9,10,13,14,18,23,24,27], the power generation performance such as current density distribution, voltage change [12, 15-17, 21, 22, 25, 26], and durability [11]. Although a few research reported the temperature distribution in the single cell of PEFC operated at high temperature [19,20,28], the temperature near the interface between PEM and catalyst layer at cathode, which is named as a reaction surface in the present paper, was not investigated.…”

mentioning

confidence: 99%

Impact of Thickness of Polymer Electrolyte Membrane on Temperature Distributions in Single Cell of Polymer Electrolyte Fuel Cell Operated at High Temperature

Nishimura¹,

Sato²,

Yoshimura³

et al. 2018

JEPE

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This study is to understand the impact of operating condition, especially initial operation temperature (T ini ) which is set in high temperature range, on the temperature profile of the interface between PEM (polymer electrolyte membrane) and catalyst layer at the cathode (i.e., the reaction surface) in a single PEFC (polymer electrolyte fuel cell). A 1D multi-plate heat transfer model based on the temperature data of separator measured using thermograph in a power generation experiment was developed to evaluate the reaction surface temperature (T react ). This study investigated the effects of T ini , flow rate and relative humidity of supply gas as well as thickness of PEM on the temperature distribution on reaction surface. As a result, the impact of flow rate of supply gas on the temperature distribution is not significant irrespective of relative humidity conditions as well as PEM type. When operated at high temperature, the temperature distribution is relatively flat in the case of thicker PEM (Nafion 115), while T react rises from the inlet to the outlet large and the temperature distribution is wide in the case of thin PEM (Nafion 211) irrespective of relative humidity condition. Since the water transfer through PEM in the case of Nafion 211 is better than Nafion 115 due to thin PEM, the power generation is promoted along the gas flow with the aid of humidification by water produced from electrochemical reaction.

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Water distribution in high temperature polymer electrolyte fuel cells

Cited by 36 publications

References 60 publications

Determination of Anion Transference Number and Phosphoric Acid Diffusion Coefficient in High Temperature Polymer Electrolyte Membranes

Determination of Anion Transference Number and Phosphoric Acid Diffusion Coefficient in High Temperature Polymer Electrolyte Membranes

Numerical Analysis of Temperature Distributions in Single Cell of Polymer Electrolyte Fuel Cell when Operated in Elevated Temperature Range

Impact of Thickness of Polymer Electrolyte Membrane on Temperature Distributions in Single Cell of Polymer Electrolyte Fuel Cell Operated at High Temperature

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