Description

The fuel cell model in Figure 1 consists of a voltage source connected to a series resistance and a diode to avoid negative current flowing to the cell. The model assumes the operation of the fuel cell at nominal temperature and pressure.

Figure 1 Fuel Cell equivalent circuit diagram

The fuel cell model described in Figure 1 represents the following transfer function

Where:

The mentioned parameters are described in Fuel Cell (FC)#Mask and Parameters section below.

Table of Contents

Mask and Parameters

Fuel Cell Parameters

Name	Description	Unit
Eoc	Open circuit voltage	V
V_1	Voltage at 1 Ampere	V
Vnom	Nominal voltage	V
Inom	Nominal current	A
Vmin	Minimum voltage	V
Imax	Maximum available current	A
tau	Response time	s

Stack Voltage vs Current

Figure 2 Fuel Cell stack voltage vs current diagram

Ports, Inputs, Outputs and Signals Available for Monitoring

Ports

Name	Description
Net_1	Network connection; the "+" indicates the current measurement direction (supports only 1-phase connections)
Net_2	Network connection (supports only 1-phase connections)

Inputs

None

Outputs

None

Sensors

Name	Description	Units
Voltage	DC output voltage produced by the Fuel Cell	pu
Current	DC output current produced by the Fuel Cell	^pu

Extraction of Data Examples

The parameters for the Fuel Cell can be directly obtained from the datasheet on the stack voltage vs current curve shown as shown in the example in Figure 2. Some examples of this process are shown below. It is recommended to use a software that allows a precise extraction of data on the figures.

PowerCell S2-50C Fuel Cell

Figure 3 below is the example of a commercial datasheet. The purpose of this section is to show how to extract the meaningful data from the Tafel slope.

Figure 3 Stack voltage vs current S2-50C.

Name	Value extracted from Figure
Eoc (V)	47.1175
V_1 (V)	46.2974
Vnom (V)	32.5
Inom (A)	144.2
Vmin (V)	30
Imax (A)	200

NedStack PS6

Figure 4 Stack voltage vs current PS6.

Figure 4 below presents another example to extract the necessary information from the Tafel slope.

Name	Value extracted from Figure
Eoc (V)	65
V_1 (V)	63
Vnom (V)	45
Inom (A)	133.3
Vmin (V)	37
Imax (A)	225

Fuel Cell (FC)