Extruding/dispensing multiple materials to form high-aspect ratio extruded structures

• US 7,799,371 B2
• Filed: 11/17/2005
• Issued: 09/21/2010
• Est. Priority Date: 11/17/2005
• Status: Expired due to Fees

• Current Assignee: SolarWorld Industries GmbH
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Hantschel, Thomas, Fork, David K.
• Primary Examiner(s): Ahmed; Shamim
• Application Number:
  US11/282,829
• Publication Number:
  US 20070108229A1
• Time in Patent Office: 1,769 Days
• Field of Search: 427/115, 427/286
• US Class Current: 427/115
• CPC Class Codes: B05B 9/06 the delivery being related to the movement of a vehicle, e.g. the pump being driven by a vehicle wheel
• CPC Class Codes: B05C 5/0254 Coating heads with slot-shaped outlet B05C5/0283 takes precedence
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/12 Articles with an irregular circumference when viewed in cross-section, e.g. window profiles
• CPC Class Codes: B29C 48/19 the layers being joined at their edges
• CPC Class Codes: B29C 48/305 having a wide opening, e.g. for forming sheets

Abstract

A method for extruding composite materials on a substrate includes feeding a first material into a first channel and a second material, used to maintain a shape of the first material, into one or more second channels residing on at least one side of the first channel, merging the flows of the first and second materials into a single flow in which the second material surrounds the first material, applying the single flow to a substrate to produce at least one composite material, and post-processing the composite material to form a solid.

Claims

1. A method for extruding/dispensing first and second materials to form a solid structure having a predetermined cross section, the method comprising:

feeding said first material into a first channel such that the first material forms a first flow in the first channel,

feeding said second material into one or more second channels residing on at least one side of the first channel such that the second material forms at least one second flow in the one or more second channels;

merging the first flow of the first material and the at least one second flow of the second material into a single volume region such that the first and second flows combine to form a single flow in which the second material contacts the first material without substantial mixing;

co-extruding the single flow from the single volume region through an orifice;

applying the single flow co-extruded from the orifice onto a surface of a substrate to produce at least one composite structure in which the second material is disposed horizontally adjacent to the first material such that both the first material and the second material are in direct contact with the surface of the substrate; and

post-processing the dispensed composite structure such that the first material forms said solid extruded structure having said predetermined cross section.

2. The method as set forth in claim 1, wherein the formed solid extruded structure is a conductive contact.

3. The method as set forth in claim 1, further including:

feeding the first material into a first set of alternating channels;

feeding the second material into a second set of channels residing between the first set of alternating channels; and

merging the flows from the first set of alternating channels and the second set of channels into said single flow disposed in the single volume region in which the first and second material are interleaved.

4. The method as set forth in claim 1, further including at least one of pushing and pulling the first and second materials through the first and second channels to produce laminar flows prior to merging the first and second materials into said single flow.

5. The method as set forth in claim 1, further including setting at least one of a flow rate, a temperature, and a duty cycle of said first and second flows based on a viscosity of the first and second materials.

6. The method as set forth in claim 1, wherein the predetermined cross-section of the first material comprises at least one of an aspect ratio of 2:

1 and a size of less than about 30 microns.

7. The method as set forth in claim 1, further including moving at least one of the channels and the substrate during extrusion to define at least one of a length, a width, a height, and a diameter of the composite structure.

8. The method as set forth in claim 1, wherein the substrate is associated with one of a solar cell, a battery and a fuel cell, and wherein the extruded structure comprises one of a high aspect ratio gridline of said solar cell and an electrode of one of said battery and said fuel cell.

9. A method for co-extruding first and second materials to form a structure having a predetermined cross section on a substrate, the method comprising:

merging said first and second materials from at least two different channels to generate a single flow in a single volume region in which the second material compresses the first material such that the first material forms the predetermined cross section inside the single volume region without substantial mixing; and

co-extruding the single flow of the first and second materials from the single volume region through an orifice onto the substrate such that both the first material and the second material are in direct contact with a surface of the substrate.

10. The method as set forth in claim 9, wherein the first material is a silver paste for creating electrodes on a solar cell and the second material is a sacrificial material used to maintain the predetermined cross sectional shape of the electrodes.

11. The method as set forth in claim 9, wherein the first material forms a fine feature on the substrate and the second material maintains the predetermined cross sectional shape of the fine feature, is transparent, and remains on the substrate.

12. The method as set forth in claim 9, the first material forms porous hydrophilic lines of an electrode of a fuel cell and the second material forms porous hydrophobic lines of the electrode of the fuel cell.

13. The method as set forth in claim 9, wherein the single flow of the first and second materials forms a gridline on a photovoltaic cell in which at least one end of the gridline is associated with a variable ratio of conducting to non-conducting material.

14. The method as set forth in claim 9, wherein the single flow of the first and second materials forms a gridline, and further including varying conductor cross-section throughout the length of the gridline.

15. The method as set forth in claim 9, further including heating at least one of the first and second materials to lower its viscosity.

16. The method as set forth in claim 9, further including UV curing the applied single flow of materials.

17. The method as set forth in claim 9, wherein at least one of the materials is a highly thixotropic.

18. A method for co-extruding/dispensing first and second materials through an output orifice defined in an applicator, the output orifice having a first width, the method comprising:

merging the first and second materials to generate a single flow within the applicator such that the second material compresses the first material into a predetermined cross section without substantial mixing before exiting the applicator through the output orifice, wherein the predetermined cross section of the first material exiting the output orifice has a second width that is smaller than the first width of the output orifice; and

applying the single flow onto a surface of a substrate such that the first material forms a high aspect ratio structure and the second material is disposed horizontally adjacent to the first material such that both the first material and the second material are in direct contact with the surface of the substrate.

19. The method as set forth in claim 18, wherein at least one of the first and second materials has a rheology closely matched to a silver paste.

20. The method as set forth in claim 18, further including utilizing temperature to affect at least one of a flow of the first and second materials and the predetermined cross sectional shape of the high aspect ratio structure.

21. A method for producing a high aspect ratio structure on a substrate surface, the method comprising:

generating a co-extruded composite structure by feeding a first material into a first channel defined in an applicator such that the first material forms a first flow in the first channel, and feeding a second material into second and third channels residing on opposing sides of the first channel such that the second material forms second and third flows in the second and third channels, respectively, wherein said applicator is configured such that the first flow of the first material merges with the second and third flows of the second material in a single volume region disposed inside the applicator to form said composite structure in which the first flow forms said high aspect ratio structure disposed between supporting structures formed by the second and third flows without substantial mixing of the first and second materials, and wherein said applicator is configured such that the composite structure exits said single volume through an outlet defined in the applicator;

applying the composite structure exiting the orifice onto the substrate surface such that the high aspect ratio structure is centrally positioned between the supporting structures and such that both the first material and the second material are in direct contact with the substrate surface; and

post-processing the composite structure to solidify the high aspect ratio structure on the substrate surface.

22. The method as set forth in claim 21, wherein the high aspect ratio structure is characterized through at least one of an aspect ratio of 2:

1 or greater and a size in the range of 100 nm to 100 microns.

23. The method as set forth in claim 21, wherein generating the composite structure comprises feeding a silver paste into the first channel and feeding a sacrificial material into the second and third channels.

24. The method of claim 23, further comprising removing the supporting structures from the substrate surface.

25. The method as set forth in claim 21, wherein post-processing comprises one of drying, curing, and sintering.

26. The method as set forth in claim 21, wherein generating the composite structure further comprises feeding one or more third materials into at least one sub-channel defined in the applicator and aligned with the first channel such that the high aspect ratio structure includes said first material and said one or more third materials disposed in vertical layers.

27. The method as set forth in claim 21, wherein generating the composite structure comprises feeding a hydrophilic material into the first channel and feeding a hydrophobic material into the second and third channels.