Process for manufacturing an electrochemical-reactor flow guide

Patent metadata

Field	Value
Publication number	US-11437638-B2
Application number	US-201916567108-A
Country	US
Kind code	B2
Filing date	Sep 11, 2019
Priority date	Sep 12, 2018
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A process for manufacturing a flow guide for an electrochemical reactor, including providing a substrate; on a first face of the substrate, printing a layer of electrically conductive ink by applying a shear stress to this layer, the viscosity of the printed ink being comprised between 70 and 500 Pa·s for a shear rate of 0.1 s−1, and the viscosity of the printed ink being comprised between 2.5 and 7 Pa·s for a shear rate of 100 s1, the layer of ink being printed to form a pattern including ribs delineating flow channels.

First claim

The invention claimed is:

1. A process for manufacturing a flow guide for an electrochemical reactor, comprising:
on a first face of a substrate, printing a layer of electrically conductive ink by applying a shear stress to the layer, a viscosity of a printed said electrically conductive ink being comprised between 70 and 500 Pa·s for a shear rate of 0.1 s −1 , and a viscosity of the printed electrically conductive ink being comprised between 2.5 and 7 Pa·s for a shear rate of 100 s −1 , the layer of electrically conductive ink being printed to form a pattern including ribs delineating flow channels.

2. The manufacturing process according to claim 1 , wherein the printing the is a screen-printing.

3. The manufacturing process according to claim 2 , wherein said screen-printing comprises depositing the electrically conductive ink on a stencil screen and applying a squeegee to the stencil screen so as to apply the shear stress to the electrically conductive ink in order to print it onto the first face of the substrate.

4. The manufacturing process according to claim 1 , further comprising drying in order to solidify the layer of electrically conductive ink of the formed pattern.

5. The manufacturing process according to claim 1 , wherein said printing comprises applying the shear stress to the layer with a shear rate comprised between 10 s −1 and 80 s −1 .

6. The manufacturing process according to claim 1 , wherein said printed layer of electrically conductive ink has a thickness at least equal to 150 μm.

7. The manufacturing process according to claim 1 , wherein the ribs have a height at least equal to half of a width of the ribs.

8. The manufacturing process according to claim 1 , wherein a solid content of said printed electrically conductive ink includes graphite particles in a proportion comprised between 90 and 99%.

9. The manufacturing process according to claim 1 , wherein a solid content of said printed electrically conductive ink represents between 50 and 75% by weight of the electrically conductive ink to which the shear stress is applied.

10. The manufacturing process according to claim 1 , wherein a solid graphite-mixture content of said electrically conductive ink includes particles having a D50 diameter comprised between 1 and 6 μm in a proportion comprised between 1 and 35% by weight, the solid graphite-mixture content of said electrically conductive ink furthermore including particles having a D50 diameter comprised between 10 and 25 μm in a proportion of at least 25% by weight.

11. The manufacturing process according to claim 1 , wherein said electrically conductive ink to which the shear stress is applied includes a polymer binder.

12. The manufacturing process according to claim 11 , wherein said electrically conductive ink to which the shear stress is applied includes polyvinylidene fluoride.

13. The manufacturing process according to claim 1 , wherein the electrically conductive ink to which the shear stress is applied has a storage modulus higher than a viscous modulus for a deformation amplitude of 1% at a frequency lower than 0.1 Hz.

14. The manufacturing process according to claim 1 , wherein the electrically conductive ink to which the shear stress is applied has a storage modulus lower than a viscous modulus for a deformation amplitude of 1% at a frequency higher than 2 Hz.

15. The manufacturing process according to claim 1 , wherein said substrate is exempt of relief level with the printed electrically conductive ink.

16. The manufacturing process according to claim 1 , wherein said substrate is an electrically conductive plate, a gas diffusion layer, or an electrode layer.

17. A process for manufacturing a bipolar plate, comprising manufacturing first to third flow guides using the manufacturing process according to claim 1 , said substrate being an electrically conductive plate for each of the first to third flow guides, a layer of electrically conductive ink being printed only on the first face of the first to third flow guides, a bipolar plate being formed by bonding second faces of the first and second flow guides and by bonding the ribs of the pattern formed on the second flow guide against a second face of the third flow guide, so as to delineate flow channels between the second and third flow guides.

18. The manufacturing process according to claim 1 , wherein
said substrate is an electrically conductive plate, and
the layer of electrically conductive ink is printed by applying the shear stress to the layer on a second face of said electrically conductive plate.

19. A process for manufacturing a bipolar plate, comprising:
manufacturing a flow guide using the manufacturing process according to claim 8 ; and
applying a face of another electrically conductive plate against the ribs of the pattern, the pattern being formed on a carrier of the flow guide.

20. A process for manufacturing a fuel-cell stack, comprising: forming a first flow guide using the manufacturing process according to claim 1 , wherein the substrate of the first flow guide is a first electrically conductive plate;
forming a second flow guide using a manufacturing process, wherein a substrate of the second flow guide is a second electrically conductive plate; and
placing a membrane/electrode assembly between said first and second electrically conductive plates, respective ribs of the patterns formed on the first and second flow plates being oriented toward the membrane/electrode assembly.

21. The process for manufacturing a flow guide according to claim 1 , wherein each of ribs of formed patterns consists of a single printed layer of ink.

22. A flow-guiding electrochemical-reactor plate, wherein it is manufactured using the manufacturing process according to claim 1 .

Assignees

• Commissariat Energie Atomique

Inventors

• Salomon Jeremie
• Amestoy Benjamin
• Blachot Jean-Francois
• Tremblay Denis

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/026

  characterised by grooves, e.g. their pitch or depth · CPC title

• H01M8/0258 Primary

  characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant · CPC title

• C09D11/102

  containing macromolecular compounds obtained by reactions other than those only involving unsaturated carbon-to-carbon bonds · CPC title

• H01M8/1067

  characterised by their physical properties, e.g. porosity, ionic conductivity or thickness · CPC title