Convection generator-collector

It may be added that generator/collector cells can be implemented without convection. Double microbands [65] and interdigitated bands [294,447, 500] have been considered for this purpose, for titrations [458, 541] and for studies in electrochemically generated chemiluminescence (ECL) [539], See also the review by Amatore [46] with more references therein. 

Forced convection (hydrodynamic) generator - collector systems are commonly employed in rotating ring-disc or wall-jet geometries or in channel flow cells to improve collection efficiencies. For macroscopic interelectrode gap systems hydrodynamic agitation can be employed to improve feedback, but for diffusion - dominated nano-gap electrode systems hydrodynamic convection effects usually remain insignificant, whereas heating can be used to enhance the rate of diffusion processes and therefore to improve feedback currents. 

Compared to small molecules the description of convective diffusion of particles of finite size in a fluid near a solid boundary has to account for both the interaction forces between particles and collector (such as van der Waals and double-layer forces) and for the hydrodynamic interactions between particles and fluid. The effect of the London-van der Waals forces and doublelayer attractive forces is important if the range over which they act is comparable to the thickness over which the convective diffusion affects the transport of the particles. If, however, because of the competition between the double-layer repulsive forces and London attractive forces, a potential barrier is generated, then the effect of the interaction forces is important even when they act over distances much shorter than the thickness of the diffusion boundary layer. For... 

As we have mentioned before, a bipolar plate serves multiple purposes in a fuel cell sfack. If serves as a current collector, dissipates the heat generated in the fuel cell by conduction through the solid material and by convection through gas channels and cooling channels, and provides the structural strength and support for the thin MEAs in the stack. Selection of a material that satisfies all these requirements is to some extent challenging and requires extensive analysis depending on the applications. 

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