Fuel cell having a hydrophilic substrate layer

Abstract

Fuel Cell Having a Hydrophilic Substrate Layer A fuel cell power plant includes a fuel cell having a membrane electrode assembly (MEA), disposed between an anode support plate and a cathode support plate, the anode and/or cathode support plates include a hydrophilic substrate layer having a predetermined pore size. The pressure of the reactant gas streams is greater than the pressure of the coolant stream, such that a greater percentage of the pores within the hydrophilic substrate layer contain reactant gas rather than water. Any water that forms on the cathode side of the MEA will migrate through the cathode support plate and away from the MEA. Controlling the pressure also ensures that the coolant water will continually migrate from the coolant stream toward the anode side of the MEA, thereby preventing the membrane from becoming dry. Proper pore size and a pressure differential between coolant and reactants improves the electrical efficiency of the fuel cell.

Description

[0001] This is a continuation-in-part of U.S. patent application Ser. No. 09 / 466,701 filed on Dec. 17, 1999.[0002] This invention relates to fuel cell power plants and more particularly, to fuel cell power plants utilizing a hydrophilic substrate layer within the anode and / or cathode of the fuel cell.[0003] Fuel cell power plants are electrochemical alternative power sources for both stationary and mobile applications. The fuel cell, which is the heart of such power plant, consists of an anode, a cathode and an electrolyte that separates the two. Anode shall mean a positive electrode, and cathode shall mean a negative electrode. In the operation of a fuel cell, fuel reactant gas, which is typically a hydrogen rich stream, enters a support plate that is adjacent to the anode. Such a support plate is, therefore, referred to as an anode support plate. Oxidant reactant gas, which is commonly air, enters a support plate adjacent to the cathode. This support plate is, therefore, referred ...

AI Technical Summary

Benefits of technology

0008] The present invention is a fuel cell power plant that includes a fuel cell having a membrane electrode assembly (MEA), which is disposed between an anode support plate and a cathode support plate and wherein the anode and/or cathode support plates include a hydrophilic substrate layer. The fuel cell power plant also includes a fuel reactant gas stream, which is in fluid communication with the anode support plate's hydrophilic substrate layer, and an oxidant reactant gas stream, which is in fluid communication with the cathode support plate's hydrophilic substrate layer, and a cooling water stream, which is in fluid communication with both the anode and cathode support plate hydrophilic substrate layers. The hydrophilic substrate layer in the anode support plate enhances the migration of the cooling water to the anode side of the MEA, and the hydrophilic substrate layer in the cathode support plate improves the removal of water from the cathode side of the MEA. The hydrophilic substrate layers within both the anode and cathode support plates have a predetermined level of porosity (i.e., number of pores) and pore size. The inventors of the present invention recognized that without controlling the number of pores within the hydrophilic substrate that contain water, the water will fill 100% of the available pores

Problems solved by technology

Specifically, without proper water removal, a reduced portion of the available oxygen reaches the catalyst.

Although U.S. Pat. No. 5,641,586 recognized that replacing the cathode hydrophobic substrate layer with a hydrophilic substrate layer increased the cell voltage, that patent failed to dis

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