Interdigitated Flow-Field

T. V. Nguyen and W. Fie. Interdigitated flow field design. In Handbook of fuel cells—Fundamentals, technology and applications, ed. W. Vielstich, H. A. Gasteiger, and A. Lamm, 325-336. New York John Wiley Sons (2003). 

W. He, J. S. Yi, and T. V. Nguyen. Two-phase flow model of the cathode of PEM fuel cells using interdigitated flow fields. AIChE Journal 46 (2000) 2053-2064. 

Hu, G., Fan, J., Chen, S., Liu, Y, Cen, K. 2004. Three-dimensional numerical analysis of proton exchange membrane fuel cells (PEMECs) with conventional and interdigitated flow fields. J Power Sources 136 1-9. 

In a multichannel flow-field design the channels with normal and lowered pressure may alternate and one may expect that the latter will effectively remove excessive water from the cathode compartment. Such a flow field may have advantages over the interdigitated flow field since gas flow in the water-draining (Red) channels is externally driven and can be varied to reach optimal conditions. 

Wood D, Yi JS, Nguyen TV (1998) Effect of direct liquid water injection and interdigitated flow field on the performance of proton exchange membrane fuel cells. Electrochim Acta 43 3795-3809... 

Zhou, T. and Liu, H.T., Heat Transfer Enhancement in Fuel Cells with Interdigitated Flow Field Design, Int. J. Computer Applications in Technology, in publication, 2002. 

Reactant supply and water removal is optimized by so called interdigitated flow fields where gas flow is forced across the ribs separating the flow field channels through the macroporous part of the gas diffusion electrodes at the expense of high pressure drop between reactant inlet and outlet. 

Um and Wang [63] used a three-dimensional model to study the effects an interdigitated flow field. The model accounted for mass transport, eleetroohemieal kinetics, species profiles and ciurent density distribution within the eell. Interdigitated flow fields result in foreed convection of gases, which aids in liquid water removal at the cathode. This would help improve performance at high current densities when transport limitations due to exeessive... 

The physical schematic diagrams of the fuel flow within the PEM fuel cell with different flow fields (a) conventional flow field and (b) interdigitated flow field. (From Yan, W.-M. et al., 2006. Journal of Power Sources, 160 284-292. With permission.)... 

A detailed survey of flow field design types is given, for example, in Li. Interdigitated flow fields are described, e.g. in Vielstich. From all configurations shown, the serpentine flow Adds have the highest technical meaning and are subject to further explanations in the following section. 

Figure 4.14 Diagrams to show the principle of humidification using interdigitated flow fields, after Wood et al. (1998).

Flow field layout plays an important role in flow field design, as it affects both reactant gas distribution and water removal. Several flow field layouts have been developed, according to their flow channels the pin-type flow field [95,96], the straight parallel flow field [97,98], the serpentine flow field [98,99], and the interdigitated flow field [100-103], as shown in Fig. 2.19. All these patterns have their own characteristics in terms of reactant gas distribution, water, and heat management, and their advantages and disadvantages have been extensively reviewed by Li and Sabir [86]. 

The interdigitated flow-field design consists of two sets of dead-ended gas flow channels as shown in Figure 10.16a. The first set of dead-ended inflow channels carries the gas stream from the inlet ports and transfers to the electrode gas diffusion layer. The gas stream is forced by advection through the porous gas diffusion layer toward the electrode-electrolyte interface and toward the second set of dead-ended outflow channels and moves toward the gas stream outlet port. 

Fig. 5 Cathode interdigitated flow field plate (1) cathode ports (2) anode ports (3) coolant ports (4) distribution area (5) collecting area (6) cathode feeding channel (active cell area) (7) cathode outlet channel (active cell area)...

Wang, L., and Liu, H. (2004) Performance studies of PEM fuel cells with interdigitated flow fields, J. Power Sources, 134, 185-196. 

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