1 Preparation of Electrical Conductive ABS Composite for Bipolar Plates in PEM Fuel Cell Dr. Jatrawan Phumchusak And Miss. Somruthai Tunma.

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Preparation of Electrical Conductive

ABS Composite for Bipolar Plates

in PEM Fuel Cell

Dr. Jatrawan Phumchusak

And

Miss. Somruthai Tunma

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Aim to prepare the electrical

conductive polymer composite bipolar plate

in order to reduce the manufacturing cost

of PEMFC

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Introduction :

Polymer Electrolyte Membrane Fuel Cell ; PEMFC

clean and potential energy sorce

high production cost

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Mass distribution in a 33 kW PEMFC stacks :

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Bipolar Plate :

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Classification of materials for BPs used in PEM fuel cell :

Non-metal : Non-porous graphite plates

Metals : Metal plates

Composites : - Metal based - Carbon based :

- Thermoplastics

- Thermosets

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Requirements for Bipolar Plates :

Electrical conductivity :

- DOE (the U.S.Department of Energy) > 100 S/cm

- F.N.Büchi ≥ 10 S/cm(Development of a Bipolar Element for PE- fuel cell, demonstration in a 6 kW stack)

- B.W.Choi ≥ 2.5 S/cm (higher than gas diffusion electrode)(J.Hydrogen energy 21 (1996))

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The BPs have the following functio ns to

perform :

- To distribute the fuel and oxidant within the cell.

- To facilitate water management within the cell.

- To separate individual cells in the stack.

- To carry current away from the cell.

- To facilitate heat management.

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Properties of BP :

Electrical conductivity : plate resistance 0.01 cm 2

Thermal conductivity : as high as possible

Hydrogen/gas permeability : 10-4 cm3/scm2

Corrosion resistance : corrosion rate 0.016 mA/cm2

Compressive strength : 22 lb/in2

Density : 5 gm/cm2

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Bipolar plate :

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Bipolar plate :

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Methodology :

2-rolls mixer

Hot pressing machine

ABS matrix

Graphite powder

Carbon black powder

Carbon fiber

Measure the in-plane electrical resistance by using the digital multimeter

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Result:

ABS–Graphite

Composites

Conductivity, S/cm

60 : 40 8.40 10-3

50 : 50 5.00 10-2

40 : 60 2.10 10-1

30 : 70 2.11

Table 1,2 : Electrical properties of ABS - Graphite composites.

Note : pure graphite

ABS–Graphite

Composites

Conductivity, S/cm

60 : 40 1.77 10-2

50 : 50 3.73 10-3

40 : 60 2.30 10-1

30 : 70 3.67

25 : 75 7.72

20 : 80 13.00

Note : mixed graphite

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Result :

ABS : CB : G

Conductivity, S/cm

25 : 5 : 70

8.16

25 : 10 : 65

9.28

30 : 20 : 50

12.95

Table 3 : Electrical properties of carbonaceous fillers - ABS composites.

Note : CB – Carbon black , G - Graphite

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Table 4 :

ABS: CF : G Composites

Conductivity,

S/cm

ABS : CF1 : G

40 : 20 : 40

0.10

ABS : CF2 : G

40 : 20 : 40

0.30

- CF1 length = 3 mm- CF2 length = 5 mm

-The effect of CF length :longer CF higher conductivity

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Discussion and Conclusion :

- Add carbon fiber to improve the conductivity of ABS composites.

- The effect of content and composition of fillers and the incorporation of fillers including the length of carbon fiber on the electrical properties of polymer composite were studied.

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References:

(1) A. Hermann, T. Chaudhuri and P. Spagnol (2005), “Bipolar plates for PEM fuel cells : A review”, International Journal of Hydrogen Energy, 30, 1297-1302.

(2) H-C. Kuan, C-C. M. Ma, K. H. Chen and S-M. Chen (2004), “Preparation, electrical, mechanical and thermal properties of composite bipolar plate for a fuel cell”, Journal of Power Sources, 134, 7-14.

(3) W. Thongruang, R. J. Spontak and C. M. Balik (2002), “Bridged double percolation in conductive polymer composites: an electrical conductivity, morphology and mechanical property study”, Polymer, 43, 3717-3725.

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Acknowledgement :

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