Process for fabricating glass-encapsulated solar cell arrays and the product produced thereby

• US 4,234,351 A
• Filed: 07/14/1978
• Issued: 11/18/1980
• Est. Priority Date: 07/14/1978
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Deminet, Czeslaw, Oettel, Richard E.
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US05/924,733
• Time in Patent Office: 858 Days
• Field of Search: 29/572, 136/89 EP, 136/89 P, 65/45, 65/44, 65/41, 65/66, 65/106
• US Class Current: 136/251
• CPC Class Codes: C03B 13/12 Rolling glass with enclosures, e.g. wire, bubbles, fibres, particles or asbestos
• CPC Class Codes: C03B 13/14 Rolling other articles , i.e. not covered by C03B13/01 - C03B13/12, e.g. channeled articles, briquette-shaped articles
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H01L 31/188 Apparatus specially adapted for automatic interconnection of solar cells in a module
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

The process includes the steps of (1) forming a pattern of indentations and adjacent boundary ridges in a base layer of glass which is heated to a temperature where it is formable but not flowing, (2) depositing electrically conducting first connecting elements on the upper surface of the base glass layer, with each first connecting element extending from an indentation to a point on an adjacent ridge, (3) positioning a solar cell into each indentation in the base glass layer in such a manner that the lower surface of the solar cell comes in electrical contact with one end of a first connecting element, (4) depositing electrically conducting second connecting elements which extend between the end of the first connecting elements on a ridge to the top surface of a solar cell in an adjacent indentation, and (5) forming a top glass layer which is in intimate contact with the product of steps 1-4. The product produced thereby is an array of glass-encapsulated solar cells which are electrically connected together by means of the first and second connecting elements but are otherwise physically isolated from each other by the glass-encapsulation.

Claims

1. A process for fabricating solar cell arrays, comprising the steps of:

a. forming a base layer of glass;

b. forming a pattern of indentations bounded by ridges in said base layer;

c. forming an electrically conducting first connecting element on said base layer, wherein said first connecting element extends from a given indentation to a point on an adjacent ridge;

d. positioning a solar cell in said given indentation so that the lower surface of said solar cell is in electrical contact with the one end of said first connecting element in said given indentation;

e. forming an electrically conducting second connecting element to extend between the other end of said first connecting element on said adjacent ridge and the top surface of a solar cell in an adjacent indentation; and

f. forming a top layer of glass on the product of steps a-e above by heating glass sufficiently until it flows, applying the flowing glass to the upper surface of the product of steps a-e above so that it fills in the irregularities thereof, and applying sufficient pressure to create an intermolecular bond between said top layer of glass and the exposed portions of the glass base layer, the solar cells and the connecting elements, the application of pressure being sufficiently time-limited to prevent migration of the existing PN junction in the solar cell.

2. The process of claim 1, including the further step of annealing the product of steps a-f of claim 1.

3. The process of claim 1, wherein said base layer of glass and said top layer of glass are at a sufficiently high temperature during the process that they are formable.

4. A process of claim 1, wherein said steps of forming said electrically conducting said first and second connecting elements are accomplished by a plasma spray through a mask.

5. The process of claim 1, wherein the glass comprising said base layer and said top layer has substantially the same coefficient of expansion as the material comprising the solar cell.

6. The process of claim 5, wherein the step of positioning the solar cell in said indentation includes the step of prewarming the solar cell so that it does not experience thermal shock when it comes into contact with said base layer.

7. The product formed by a process for fabricating solar cell arrays which comprises the steps of:

a. forming a base layer of glass;

b. forming a pattern of indentations bounded by ridges in said base layer;

c. forming an electrically conducting first connecting element on said base layer, wherein said first connecting element extends from a given indentation to a point on an adjacent ridge;

d. positioning a solar cell in said given indentation so that the lower surface of said solar cell is in electrical contact with the one end of said first connecting element in said given indentation;

e. forming an electrically conducting second connecting element to extend between the other end of said first connecting element on said adjacent ridge and the top surface of a solar cell in an adjacent indentation; and

f. forming a top layer of glass on the product of steps a-e above by heating glass sufficiently until it flows, applying the flowing gas to the upper surface of the product of steps a-e above so that it fills in the irregularities thereof, and applying sufficient pressure to create an intermolecular bond between said top layer of glass and the exposed portions of the glass base layer, the solar cells and the connecting elements, the application of pressure being sufficiently time-limited to prevent migration of the PN junction in the solar cell.

8. A glass-encapsulated solar cell array, comprising:

a base layer of glass having at least two indentations therein which are bounded by ridges;

solar cells positioned in said indentations;

an electrically conducting first connecting element positioned on said base layer of glass so that it extends from a beginning point in one of said indentations between said base layer of glass and the lower surface of said solar cell to a termination point on a ridge bounding said one indentation;

an electrically conducting second connecting element extending between said first connecting element and the top surface of the other solar cell in an adjacent indentation; and

a top layer of glass which covers the exposed upper surfaces of said base layer, said solar cells and said first and second connecting elements and is directly bonded thereto in an intermolecular bond.

9. An array of claim 8, wherein said base layer of glass includes a plurality of said indentations, substantially bounded by ridges, each indentation adapted to receive a solar cell.

10. An array of claim 8, wherein the glass comprising said base and top layers has substantially the same coefficient of expansion as the material comprising the solar cells.

11. An array of claim 10, wherein substantially all of the residual strain in the article caused by the manufacture of the article has been relieved.

12. An array of claim 11, wherein said first and second connecting elements are a metal film.