Photocell, its method of manufacture, and a solar panel comprising such cells

• US 5,542,988 A
• Filed: 10/17/1994
• Issued: 08/06/1996
• Est. Priority Date: 02/17/1993
• Status: Expired due to Fees

• Current Assignee: Agence Spatiale Europeenne
• Original Assignee: Agence Spatiale Europeenne
• Inventors: Bogus, Klaus P. M.
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/325,451
• Time in Patent Office: 659 Days
• Field of Search: 136/244-245, 136/256, 136/292, 437/2-5
• US Class Current: 136/244
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10S 136/292 Space - satellite

Abstract

The present invention relates to a photocell including means for providing protection against the accumulation of electrostatic charge, to a method of manufacturing it, and to a solar panel including such cells.

A photocell of the invention includes a circuit for drawing off electrostatic charge that is efficient but is of low mass and that masks incident solar radiation very little.

The circuit for drawing off charge comprises a grid of material that is optionally transparent on the outside surface of the protective glass sheet of the photocell, said grid being connected to the cell'"'"'s electrode for current collection. Advantageously, the grid of the circuit for drawing off electrostatic charge is superposed over the grid of the electrode for collecting the current generated by the photocell.

Claims

1. A photocell comprising;

a photovoltaic body having a first main face carrying a first electrode for collecting current, and a second main face opposite its first main face and carrying a second electrode for collecting current; and

a protective glass sheet bonded to said photovoltaic body;

the photocell including;

a grid of conductive elements for drawing off electrostatic charge and superposed over the elements of the first electrode, the grid being made of a substantially transparent material deposited on the outside face of the protective glass sheet and, means for interconnecting the first electrode and the grid for drawing off electrostatic charge comprising a channel section electrical conductor bar extending substantially along the entire length of the edge of the protective glass sheet and overlying a busbar of the first electrode.

2. A photocell according to claim 1, wherein the substantially transparent grid of conductive elements for drawing off electrostatic charge is made of indium tin oxide.

3. A photocell according to claim 1, wherein the grid for drawing off electrostatic charge is deposited on the outside face of the protective glass sheet by vacuum evaporation.

4. A photocell according to claim 1, wherein the protective glass sheet is secured to the photovoltaic body by a film of PTFE whose thickness is in the range 20 μ

m to 50 μ

m.

5. A photocell according to claim 1, wherein the protective glass sheet is secured to the photovoltaic body by a film of PTFE whose thickness is in the range 25 μ

m to 50 μ

m.

6. A solar panel, in particular for use in space, comprising a plurality of photocells according to claim 1, connected in series and/or in parallel.

7. A photocell comprising;

a photovoltaic body having a first main face carrying a first electrode for collecting current, and a second main face opposite its first main face and carrying a second electrode for collecting current; and

a protective glass sheet bonded to said photovoltaic body;

the photocell including;

a grid of conductive elements for drawing off electrostatic charge and superposed over the elements of the first electrode, the grid being made of a substantially transparent material deposited on the outside face of the protective glass sheet and, means for interconnecting the first electrode and the grid for drawing off electrostatic charge comprising a channel section electrical conductor bar extending substantially along the entire length of the edge of the protective glass sheet and overlaying a busbar of the first electrode, said channel section electrical conductor bar being held resiliently on the edge of the protective glass sheet.

8. A method of manufacturing a photocell, comprising the steps of:

a) placing a thin film of PTFE between a photovoltaic body and a protective glass sheet;

b) applying an intense electric field to press the glass sheet against the photovoltaic body;

c) heating the assembly to a high temperature until the protective glass sheet softens;

including the following steps prior to or during step a), of

d) fixing, on one edge of the protective glass sheet, a conductive bar connected to a grid for drawing off charge;

e) placing solder on the edge of the PTFE film, the melting temperature of the solder being not greater than the heating temperature used during step c; and

f) aligning both the solder and the conductive element connected to the grid for drawing off electrostatic charge with a busbar;

such that when the temperature is raised during step c), the first electrode is connected to the grid for drawing off electrostatic charge and simultaneously the photovoltaic body is secured to the protective glass sheet.