**Analysis and Extension of a PEMFC Model**

**Analysis and Extension of a PEMFC Model**

*J. Piotrowski, A. Häffelin (Robert Bosch GmbH) *

*R. Vetter, J.O. Schumacher (ZHAW Winterthur)*

**Approach**

*Employing and Coupling provided model*

_{Macro-homogeneous, two-phase, one dimensional through-plane }

**Membrane-Electrode-Assembly (MEA) model provided by Institute of **

Computational Physics (ICP) at ZHAW Winterthur

### (

### www.isomorph.ch

### )

[1] _{Variation of one parameter at a time}

**Motivation**

*Analyzing model behavior *

Investigation of performance losses with respect to activation, ohmic

charge transport and concentration limitation

_{Reproduction of transport limitations considering correlated parameter }

variations

Joseph Piotrowski, Andreas Häffelin | ModVal 2018 | 12-13 April 2018 Aarau, Switzerland

**Summary and Outlook**

_{Sensitivity of all model}

parameters has been investigated

Expansion by coupling of 1D gas

channels to existing MEA-model

**Challenges**

_{Identification of parameters with major influence and evaluation of }

their sensitivity on cell performance

Implementing and coupling gas channels to provided model

**Results of Sensitivity Analysis and Coupled Model**

*2D along-the-channel model – MEA*

_{Oxygen depletion along-the-channel and through-plane}

_{Water vapor saturation along-the-channel}

*Variation of back diffusion coefficient*

[3] _{in 1D MEA model}

_{in 1D MEA model}

_{High back diffusion}

leads to higher water content in

electrolyte and, thus perfomance

increase

_{Low back diffusion}

shows transport limitation due to membrane dry out

*2D along-the-channel model – cathode gas channel*

_{Fit parameters (least square root)}

§ _{fuel cross over correction !}_{"#$}

§ exchange current density, cathode %_{&}
§ proton conductivity '_{(}

**Modeling**

Based on analytical approach [2]

§ _{Ideal gas, laminar flow, isotherm}

§ _{Ideal evaporation and condensation at GDL|CGC }
interface (shaded area)

_{Coupling variables change locally}

_{Solution is determined by solving }

fully-coupled equation system

Current density

*2D along-the-channel model *

*1D CGC model *

*Fit to experimental data *

C el l vol ta ge P ow er de ns it y

ACL PEM CCL ACL PEM CCL ACL PEM CCL

Cathode gas channel (CGC)

Oxygen decrease along the

channel

_{Gas phase saturates with water }

vapor along the channel

_{Liquid water saturation increases }

after condensation occurs

_{Velocity decreases due to }

gas-liquid interaction
*T = 65°C, *
*RH = 0.95/0.9, *
p = 2.2 bar
T = 70°C,
RH_{in}= 0.9,
p_{in}= 2.2 bar,
ζ = 4,U = 0.6 V

*Literature*

[1] Roman Vetter and Jürgen O. Schumacher. „Free Open Reference Implementation of a Two-Phase PEM Fuel Cell Model“ (2018). Submitted to Computer Physics Communications.

[2] Yun Wang. „Porous-Media Flow Fields for Polymer Electrolyte Fuel Cells II. Analysis of Channel Two-Phase
**Flow“. Journal of the Electrochemical Society 156.10 (2009)**

[3] Ahmet Kusoglu and Adam Z. Weber. „New Insights into Perflourinated Sulfonic-Acid Ionomers“. Chemical
**Reviews 117.3 (2017)**
0.16
0.15
0.14
0.13
T = 65°C, p_{A,C} = 2.2 bar,
RH_{A} = 0.9, RH_{C} = 0.95
T = 70°C,
RH_{in} = 0.9,
p_{in} = 2.2 bar,
ζ_{C} = 4,
U = 0.6 V ,
I = 1.03 A/cm²

_{In total, 48 parameters have been varied, 15 show great influence}

*Outlook*

_{Material specific parameterization}

based on experimental data

Improving robustness of solving

process

*Summary*

_{1D gas channel implementation based }