EMR’16 UdeS - Longueuil June 2016 - EMRwebsite - … - Thermal... · 08/07/2016 1 EMR’16 UdeS - Longueuil June 2016 Summer School EMR’16 “Energetic Macroscopic Representation”

08/07/2016

1

EMR’16

UdeS - Longueuil

June 2016

Summer School EMR’16

“Energetic Macroscopic Representation”

Thermal hybridization and heating

strategies of a fuel cell / battery pack

system using EMR

A. Amamou1, L. Boulon1,2, S.Kelouwani1, K.Agbossou1,2, P.Sicard2

1Institut de Recherche sur l’Hydrogène

2Groupe de Recherche en Électronique Industrielle

Université du Québec à Trois-Rivières, Québec, Canada

EMR’16

UdeS - Longueuil

June 2016



1- Introduction

2- Thermal management strategies

3- System Description

4- Model development

5- Simulation Results

6- Conclusion

08/07/2016

2

EMR’16

UdeS - Longueuil

June 2016



«Introduction»

EMR’16

UdeS - Longueuil

June 2016



• Reduce reliance on oilimports

• Increase energy supply tomeet growing demand

• Improve environmentalquality

- Greenhouse gas emissions

- Meeting/air emissionregulations

Global greenhouse gas emissions for selected countries 1990, 2005 and 2011 [1]

08/07/2016

3

EMR’16

UdeS - Longueuil

June 2016



Zero emission

High fuel efficiency high power densities

Quick response

low operating temperature

EMR’16

UdeS - Longueuil

June 2016



The formed ice can :

• Reduce the performance

• Damage the cell components

• Block the gas passages

• Coat the catalyst

• lead to cold start failure

08/07/2016

4

EMR’16

UdeS - Longueuil

June 2016



Technical Solutions for heating up the fuel cell

Waste heat

External fluid based warm-up systems

Hot air forced ventilation using a

compressor

[LHO,07]

The exothermicchemical reaction Operate the stack

near short circuit conditions

EMR’16

UdeS - Longueuil

June 2016



«Thermal management strategies»

08/07/2016

5

EMR’16

UdeS - Longueuil

June 2016



Thermal management

strategies

Keep warm strategy

Thaw at start strategy

Maximize the energy efficiency and optimize the startup time

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22-30

-20

-10

0

10

20

30

40

50

60

Time (hour)

Te

mp

era

ture

(°C

)

Thaw at Start strategy

Keep-Warm strategy

Fuel cell temperature evolution after shutdown for both strategies at -20 °C

EMR’16

UdeS - Longueuil

June 2016



«System Description»

08/07/2016

6

EMR’16

UdeS - Longueuil

June 2016



PEMFC

Heater

Battery

Natural convective

heat transfer

m w

Tfc

Tamb

Tw,in

Tw,out

Electrical connectionHeating fluid flow

Heat flow

EMR’16

UdeS - Longueuil

June 2016



• A Proton Exchange Membrane Fuel Cells with 25 cells (Hyteon).

• A heater with a maximum heating power of 5 kW.

• An anti-freeze fluid (a mixture of water and glycol)

• A Lithium GBS-LFMP100Ah battery with 32 cells

Parameters Values

Fuel cellN 23 cells

mfc 12 [kg]Cfc 700 [J·kg-1·K-1]

Tfc,min 5°CTfc,max 60°C

Nominal voltage (V) 3.2

Max.

discharging

current

Consistent

current

<= 300

Impulse current <= 1000

Internal resistance 1.8 mΩ

Working temperature [-20°C ; 65°C]

Energy

delivered at

-20°C (Wh)

Discharging

current (A) : 50183

Discharging

current (A) :

100

215

Battery discharging cycles and battery temperature evolutions atfour temperatures tests for a constant discharging current of 50A [3].

Characteristics of Lithium GBS-LFMP100Ah battery [3].

08/07/2016

7

EMR’16

UdeS - Longueuil

June 2016



«Model development»

EMR’16

UdeS - Longueuil

June 2016



Electro-thermal model

• Determine the heating time, power and energy requirements for both strategies;

• Energetic Macroscopic Representation (EMR) is used to represent the model;

• Inputs : Flow rate of fluid (mw), heating power (Phemax);

• Outputs : Fuel cell temperatures (Tfc), power and energy requirements (Phe, Ehe), Heating time (ts );

Electrical modelV = OCV – r * i

Phe = R * i²

Thermal modelmW CW TW = Phe - 𝑤ℎ𝑒mFC CFC Tfc = - 𝑎𝑚𝑏 + 𝑤ℎ𝑒

𝑄𝑤ℎ𝑒 = Kw (Tw,in - Tfc)𝑎𝑚𝑏= hnc Snc (Tfc - Tamb)

Electrothermal model linked by a heater

Phemax

Outputs

Outputs

(Tfc0, Tfc,ref ,Tw0, Tamb)

(power and energy requirements (Phe, Ehe))

Inputs(Tfc0 ,Tfc,ref ,Tw0

,Tamb , Phemax)

08/07/2016

8

EMR’16

UdeS - Longueuil

June 2016



Electrical model

V = OCV – r * ich

∆𝑆ℎ𝑒 =𝑅 𝑖𝑐ℎ

2

𝑇𝑤

Battery

Heat exchanger

Thermal model

Heat exchanger / Fluid

Fluid/ FC/ Environment

FC / Fluid(water forced convection)

FC / Environment(natural convection)

Entropy : 𝑆 = / T [4] × T ≠ Power

𝑇𝑤 = 𝑇𝑤0 +1

𝑚𝑤𝐶𝑤 ∆𝑆ℎ𝑒 − ∆𝑆𝑤 𝑇𝑤 𝑑𝑡

𝑇𝑓𝑐 = 𝑇𝑓𝑐0 +1

𝑚𝑓𝑐𝐶𝑓𝑐 ∆𝑆𝑤 − ∆𝑆𝑎𝑚𝑏 𝑇𝑓𝑐 𝑑𝑡

∆𝑆𝑤 =𝐾𝑤𝑇𝑤(𝑇𝑤 − 𝑇𝑓𝑐)

∆𝑆𝑤2=𝐾𝑤𝑇𝑓𝑐

(𝑇𝑤 − 𝑇𝑓𝑐 )

∆𝑆𝑎𝑚𝑏 =ℎ𝑛𝑐 𝑆𝑛𝑐

𝑇𝑓𝑐(𝑇𝑓𝑐 − 𝑇𝑎𝑚𝑏)

(1)

(2)

(3)

(4)

(5)

(6)

(7)

EMR’16

UdeS - Longueuil

June 2016



• The electric behavior is not considered and the stack is only represented by a thermal model;• The thermal model of PEMFC is represented by the average specific heat capacity (Cfc) and

the heating thermal mass (mfc);• The maximum heating power of the warm-up system is 5 kW;• The flow rate of the liquid is constant ;• The initial temperature of the fluid, the stack and the environment are known.

Global Energetic Macroscopic Representation

The control path

08/07/2016

9

EMR’16

UdeS - Longueuil

June 2016



«Simulation Results»

EMR’16

UdeS - Longueuil

June 2016



0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

-20

-10

0

10

20

30

40

50

60

Te

mp

era

ture

(°C

)


Keep-Warm strategy

0 1 2 3 4 5 6 7 8 9 10 11 12 13 140

100

200

300

400

500

600

700

800

900

1 000

Time (hour)

En

erg

y r

eq

uire

d (

KJ)

D

Keep Warm

• The Keep Warm strategy continuouslyrequires energy;

• The Keep-Warm strategy does not allow thestack to freeze and Tfc remains in itstemperature operating range;

• A low heating power (383 W) is required tokeep Tfc around Tfcmin at -20°C.


• Energy requirement depends only on theinitial stack temperature;

• Energy requirement does not vary with vehiclestorage time;

• A high heating power (5 KW) is required toraise Tfc from subfreezing temperature to Tfcminduring a certain heating time (ts).

Comparison of energy consumption between Thaw at Start and Keep- Warm strategies at -20°C

08/07/2016

10

EMR’16

UdeS - Longueuil

June 2016



-30 -25 -20 -15 -10 -5 00

2

4

6

8

10

12

14

16

18

20

22

Temperatures (°C)

Tim

e (

ho

ur)

-40°-35°-30°-25°-20°-15°-10°-5°0°5°0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

Temperatures (°C)

He

atin

g tim

e (

s)

• A higher temperature provides a significantincrease in D (by roughly 15 hours for anambient temperature rising from -20°C to 0°C);

• D is highly dependent on the ambienttemperature.

• Decreasing Tamb provides a significantincrease in ts (by roughly 101 seconds for anambient temperature drop from 0°C to -40°C);

• ts highly depends on the heating power andambient temperature;

• The Keep Warm strategy is always moreadvantageous in term of cold start-up time.

The break-even parking duration (D) evolution curve for various ambient temperatures

Heating time evolution of Thaw at Start strategy for different ambient temperatures

EMR’16

UdeS - Longueuil

June 2016



«Conclusion»

08/07/2016

11

EMR’16

UdeS - Longueuil

June 2016



Conclusion

• The main focus of this study is to present a thermal management system modelthat allows the comparison of energy, power and heating time requirements forthe Keep Warm and Thaw at Start strategies;

• Simulation results show that the Keep-Warm strategy is more effective for a shortparking time and for mild sub-freezing temperatures but becomes inefficient forlong parking time;

• The Thaw at Start strategy requires less energy for long parking time, yet,requests high-power and significant time to start;

• Ambient temperature and parking time are the most important factors affectingthe cold startup time and energy requirements.

EMR’16

UdeS - Longueuil

June 2016



Conclusion

• After this study, we have chosen the thaw at start stategy for cold startup becauseit’s difficult to predict the parking time

• After that, we developed an experimental test to identify the critical parametersfor cold startup of PEMFC like stochiometrie, short circuit, voltage, hydrogenpressure and purge

• A semi-empirical model has been proposed and tested for online identification inorder to improve the cold startup from -20°C

08/07/2016

12

EMR’16

UdeS - Longueuil

June 2016



« BIOGRAPHIES AND REFERENCES »

EMR’16

UdeS - Longueuil

June 2016



[1] R. n. Canada. (2013). Global greenhouse gas emissions for selected countries 1990, 2005 and

2011. Available: http://www.rncan.gc.ca/energie

[2] R. n. Canada. (2013). Distribution of greenhouse gas emissions by economic sector, Canada, 2013. Available: http://www.rncan.gc.ca/energie

[3] J. Jaguemont, L. Boulon, Y. Dube, and D. Poudrier, "Low Temperature Discharge Cycle Tests for a Lithium Ion Cell," in 2014 IEEE Vehicle Power and Propulsion Conference (VPPC), 2014, pp. 1-6.

[4] L. Boulon, THESE, "Modélisation multiphysique des éléments de stockage et de conversion d’énergie pour les véhicules électriques hybrides. Approche systémique pour la gestion d’énergie, 2009, pp. 25-80.

http://www.rncan.gc.ca/energie

http://www.rncan.gc.ca/energie

08/07/2016

13

EMR’16

UdeS - Longueuil

June 2016



Documents

EMR’16 UdeS - Longueuil June 2016 - EMRwebsite - … - Thermal... · 08/07/2016 1 EMR’16 UdeS - Longueuil June 2016 Summer School EMR’16 “Energetic Macroscopic Representation”