Systems and methods for targeted annealing of photovoltaic structures

Patent metadata

Field	Value
Publication number	US-10236406-B2
Application number	US-201514866817-A
Country	US
Kind code	B2
Filing date	Sep 25, 2015
Priority date	Dec 5, 2014
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

A targeted-annealing system can automatically cure a conductive paste that may bind cascaded strips of a string. The targeted-annealing system can include a first heat-treating bar that may be heated to a first curing temperature, and can include a second heat-treating bar that may be heated to a second curing temperature. During operation, a controller of the targeted-annealing system can activate one or more actuators to conform the first heat-treating bar to a top surface of two cascaded strips, and conform the second heat-treating bar to a bottom surface of two cascaded strips. The first and second heat-treating bars may be aligned along an overlap portion between the two cascaded strips, and can heat the overlap portion to 160 degrees Celsius.

First claim

What is claimed is:

1. An annealing system comprising:
a first heat-treating bar operable to be heated to a first curing temperature;
a second heat-treating bar operable to be heated to a second curing temperature;
a first actuator operable to conform the first heat-treating bar to a top surface of a first photovoltaic strip of two cascaded photovoltaic strips, wherein the two cascaded photovoltaic strips comprise the first photovoltaic strip with a first busbar on a bottom surface opposite the top surface of the first photovoltaic strip and a second photovoltaic strip with a second busbar on a top surface of the second photovoltaic strip, wherein the first and the second busbars overlap in an overlap region, and wherein the first heat-treating bar is configured to be aligned along the overlap region of the two cascaded photovoltaic strips; and
a second actuator configured to conform the second heat-treating bar to a bottom surface of the second photovoltaic strip opposite the top surface of the second photovoltaic strip, wherein the second heat-treating bar is configured to be aligned along the overlap region of the two cascaded photovoltaic strips.

2. The annealing system of claim 1 , wherein a respective heat-treating bar comprises a compression spring operable to supply compression between the heat-treating bar and a corresponding actuator while the corresponding actuator presses the respective heat-treating bar against the two cascaded photovoltaic strips.

3. The annealing system of claim 1 , further comprising a string platform comprising an opening, wherein the string platform is configured to support the two cascaded photovoltaic strips with the overlap region positioned over the opening so that the second heat-treating bar is able to access the bottom surface of the second photovoltaic strip.

4. The annealing system of claim 3 , wherein the string platform is configured to support a string of cascaded photovoltaic strips, wherein the string extends in a first direction and wherein busbars of photovoltaic strips in the string extend in a second direction perpendicular to the first direction, and wherein the string platform comprises a series of two or more openings with spacing in the first direction equal to a spacing between overlap regions of neighboring sections of the string of cascaded photovoltaic strips.

5. The annealing system of claim 3 , wherein the first heat-treating bar is oriented overhead the string platform, and wherein the second heat-treating bar is oriented below the string platform.

6. The annealing system of claim 4 , wherein the first heat-treating bar is mounted to a bottom surface of an overhead platform comprising a plurality of first heat-treating bars oriented overhead the string platform, and wherein the plurality of first heat-treating bars have a spacing in the first direction equal to the spacing between overlap regions of neighboring sections of the string of cascaded photovoltaic strips.

7. The annealing system of claim 5 , wherein the second heat-treating bar is mounted on an underside platform comprising a plurality of second heat-treating bars oriented below the string platform, wherein the plurality of second heat-treating bars have a spacing in the first direction equal to the spacing between overlap regions of neighboring sections of the string of cascade photovoltaic strips and are aligned with the series of two or more openings.

8. The annealing system of claim 3 , further comprising an actuator operable to move the string platform to align a second section of a string to the first and second heat-treating bars, wherein the string comprises the two cascaded photovoltaic strips and a second pair of cascaded photovoltaic strips, and wherein the second section comprises the second pair of cascaded photovoltaic strips.

9. The annealing system of claim 1 , further comprising an actuator operable to move the first and second heat-treating bars to align with a second overlap region of a second set of cascaded photovoltaic strips.

10. The annealing system of claim 1 , wherein a respective heat-treating bar includes an electric heat source, operable to heat a surface of the respective heat-treating bar to a target curing temperature.

11. The annealing system of claim 1 , wherein the first curing temperature or the second curing temperature is approximately 160 degrees Celsius.

12. The annealing system of claim 10 , further comprising at least one fan operable to prevent the heat-treating bar from reaching a temperature above an upper threshold.

Assignees

• Solarcity Corp

Inventors

• Gonzalez Pablo
• Yang Bobby

Classifications

• H10P72/0432

  mainly by conduction · CPC title

• H01L31/1864 Primary

  Electricity · mapped topic

• H01L31/188

  Electricity · mapped topic

• H01L31/0504

  Electricity · mapped topic

• H05K3/1283

  After-treatment of the printed patterns, e.g. sintering or curing methods · CPC title