FUEL CELL AND MOTOR VEHICLE

• US 20170309926A1
• Filed: 07/24/2015
• Published: 10/26/2017
• Est. Priority Date: 09/04/2014
• Status: Active Grant

• Current Assignee: Audi AG (Volkswagen AG)
• Original Assignee: Volkswagen AG
• Inventors: JENSSEN, Dirk, ZILLICH, Christian Martin
• Granted Patent: US 10,581,087 B2
• Time in Patent Office: Days
• CPC Class Codes: C23C 4/10 Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2250/20 Fuel cells in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 8/0228 in the form of layered or coated products
• CPC Class Codes: H01M 8/0245 in the form of layered or coated products
• CPC Class Codes: H01M 8/026 characterised by grooves, e.g. their pitch or depth
• CPC Class Codes: H01M 8/04171 using adsorbents, wicks or hydrophilic material
• CPC Class Codes: H01M 8/04253 Means for solving freezing problems
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

The invention concerns a fuel cell (100), comprising a stack (1) of alternating bipolar plates (113) and membrane electrode assemblies (114) as well as flow channels (104, 105) that are designed between a bipolar plate (113) and a membrane electrode assembly (114) and flow channels (104, 105) that are designed within a bipolar plate (113) as well as a motor vehicle with such a fuel cell. Provision is made that a surface (101) of at least a part of the flow channels (104, 105) that is overflowable by a fluid has, regarding its direction of extension at least in part a hydrophobic segment (101a) and a hydrophilic segment (101b) with regard to a cross-section of the flow channel (104, 105).

Claims

1. A fuel cell comprising:

a stack of alternating bipolar plates and membrane electrode units;

a plurality of flow channels formed in the bipolar plates, a surface a part of the flow channels includes a hydrophobic segment and a hydrophilic segment with regard to a cross-section of the flow channel, the stack is positioned to have the flow channels run horizontally and at least a part of the hydrophilic segment is positioned on a lower portion of the flow channels.

2. The fuel cell according to claim 1 wherein the stack includes a distribution area and an active area, and the part of the flow channels that have the hydrophobic and hydrophilic segments are configured to transport reactant gas are arranged in the distribution area of the stack.

3. The fuel cell according to claim 1 wherein at least a part of the hydrophobic segment is positioned on an upper portion of the flow channels.

4. The fuel cell according to claim 1 wherein the hydrophobic segments are arranged on the bipolar plate.

5. The fuel cell according to claim 4 wherein the hydrophobic segments are developed by hydrophobization of the bipolar plate.

6. The fuel cell according to claim 5 wherein the bipolar plate is hydrophobized by coating and/or roughening of the surface.

7. The fuel cell according to claim 1 wherein a capillary force FK of water within the flow channels having the hydrophilic and the hydrophobic segment is at least 50% smaller than a capillary force FK of water within a flow channel with the same geometrical design and cross-section that has a homogeneous wettability across the entire cross-section.

8. The fuel cell according to claim 7 wherein the capillary force FK is adjustable via a dimensional ratio of the hydrophobic segments to the hydrophilic segments.

9. The fuel cell according to claim 7 wherein the capillary force FK is adjustable via a static contact angle of water of the hydrophobic segments.

10. A motor vehicle, comprising:

a fuel cell that includes;

a plurality of membrane electrode units;

a plurality of bipolar plates positioned adjacent to ones of the membrane electrode units, each plate including;

a plurality of flow channels, at least some of the flow channels including an interior surface having a first portion and a second portion; and

a hydrophobic material on the first portion; and

a hydrophilic material on the second portion.

11. The motor vehicle of claim 10 wherein the first portion of the interior surface is arranged above the second portion of the interior surface.

12. The motor vehicle of claim 10 wherein each bipolar plate includes two plates, each plate having a plurality of grooves, the at least some of the flow channels being formed in ones of the plurality of grooves.