A Flow Field for Reducing Mass Transfer Polarization in the Cathode of a Direct Methanol Fuel Cell

Abstract

Provided is a flow field for reducing mass transfer polarization of the cathode of a direct methanol fuel cell. The invention provides a bipolar plate flow field which is provided with an inlet, an outlet, and a flow channel of a multi-unit symmetrical toothed comb type. Each unit is composed of a pair of mirror-symmetric toothed combs of which the teeth cross each other. The units are arranged inturn in the direction from the inlet to the outlet. The flow field can promote the axial mass transfer of the electrodes, reduce the mass transfer polarization of the cathode and improve the performance of fuel cells, and is easy to process and convenient for large-scale production. The flow field has low resistance than the traditional interdigital flow field, and greatly reduces the energy consumption of the fuel cell system. Branch flow channels are arranged under branch flow channels, that is, secondary branch flow channels are arranged in a staggered manner. The channels under the ridgeare shorter, so that the air resistance of the flow field is smaller.

Description

technical field [0001] The invention belongs to the improvement technology of fuel cell device. To be precise, it belongs to the cathode flow field improvement technology of direct methanol fuel cells. Background technique [0002] At present, the bipolar plate structures of direct methanol fuel cells include snake-shaped, interdigitated, and leaf-shaped grooves, among which the snake-shaped groove has a simple structure and a long stroke. It will bring a greater burden to the air pump for cathode gas supply, and the longer ridges have greater adhesion to water droplets, making it difficult for water droplets to gather in the diffusion layer under the ridges, resulting in poor cathode axial mass transfer. The traditional interdigitated flow field has greater resistance than the serpentine flow field, because the inlet and outlet of the serpentine flow field are connected by grooves, while the interdigitated flow field has no groove connection, and the gas transmission can o...

AI Technical Summary

Problems solved by technology

[0002] At present, the bipolar plate structures of direct methanol fuel cells include snake-shaped, interdigitated, and leaf-shaped grooves, among which the snake-shaped groove has a simple structure and a long stroke. It will bring a greater burden to the air pump for cathode gas supply, and the longer ridge has greater adhesion to water droplets, making it difficult for water droplets to gather in the diffusion layer under the ridge, resulting in poor axial mass transfer effect of the cathode

The traditional interdigitated flow field has greater resistance than the serpentine flow field, because the inlet and outlet of the serpentine flow field are connected by grooves, while the interdigitated flow field has no groove connection, and the gas transmission can only pass through the diffusion layer under the ridge.

Images