System and method for prevention of open loop damage during or immediately after manufacturing

• US 8,039,730 B2
• Filed: 08/17/2009
• Issued: 10/18/2011
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Tigo Energy, Inc
• Original Assignee: Tigo Energy, Inc
• Inventors: Kikinis, Dan, Arditi, Shmuel, Hadar, Ron
• Primary Examiner(s): Neckel; Alexa
• Assistant Examiner(s): Berdichevsky; Miriam
• Application Number:
  US12/542,632
• Publication Number:
  US 20100139732A1
• Time in Patent Office: 792 Days
• Field of Search: 327/214
• US Class Current: 136/243
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H01L 31/03767 presenting light-induced characteristic variations, e.g. Staebler-Wronski effect
• CPC Class Codes: H02S 50/00 Monitoring or testing of PV systems, e.g. load balancing or fault identification
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10S 136/293 Circuits

Abstract

A solar cell having an open loop voltage that approaches a critical voltage range when exposed to light. A circuit, connected to the solar cell, is configured to load the solar cell when the open loop voltage of the solar cell reaches a threshold within a predetermined range of the critical voltage range.

Claims

1. A solar energy generation system, comprising:

a solar cell which, when exposed to light and connected to no load, generates an open loop voltage as a function of time, the function having a bend around a nominal junction voltage, the bend having a critical voltage range in the function; and

a circuit, connected to the solar cell, the circuit comprising a controller and a switching device configured to provide a load to the solar cell in response to a voltage produced by the solar cell reaching the critical voltage range, the load being sufficient to prevent the voltage produced by the solar cell from exceeding the critical voltage range.

2. The system of claim 1 wherein the circuit includes a Zener diode.

3. The system of claim 1 wherein the circuit includes a bipolar junction transistor.

4. The system of claim 1 wherein the circuit includes a FET transistor.

8. The system of claim 1 wherein the circuitry is integrated in the solar cell.

9. The system of claim 8 wherein the circuitry is connected to leads connecting the solar cell to adjacent solar cells.

10. The system of claim 9 wherein the circuitry is connected to a metallization pad connected to a first lead from a bottom of the solar cell, the circuitry formed in a top layer of the solar cell.

11. The system of claim 1 wherein the circuitry is formed external to the solar cell.

12. The system of claim 11 wherein the circuitry is connected to leads connecting the solar cell to adjacent solar cells.

19. The system of claim 1 wherein the load comprises a switching device.

20. The system of claim 1 wherein the load is provided after the voltage produced by the solar cell exceeds the nominal junction voltage.

5. A solar energy generation system, comprising:

a solar cell to produce a voltage;

a circuit comprising a switching device, the circuit connected to the solar cell to load the solar cell when the voltage of the solar cell reaches a threshold; and

a controller, connected to the switching device, configured to turn off the switching device when the controller determines that a value of a load connected to the solar cell is more than a preset threshold.

6. The system of claim 5 wherein the controller can be programmed to store the preset threshold.

7. The system of claim 5 further comprising a resistor, connected to the controller, to indicate the value of the load.

18. The system of claim 5 wherein the switching device comprises a FET transistor.

13. A solar energy generation system, comprising:

a solar cell having a critical voltage range of open loop voltage; and

a circuit, connected to the solar cell, configured to provide a load to the solar cell in response to a voltage produced by the solar cell reaching the critical voltage range, the load being sufficient to prevent the voltage from exceeding the critical voltage range;

wherein the solar cell includes auxiliary electrodes, in addition to a main electrode, and wherein the circuit is to further generate pulses and provide the pulses to the auxiliary electrodes to remove a buildup of unipolar and dipolar charges in the solar cell.

14. The system of claim 13 wherein the auxiliary electrodes are formed in a top layer of the solar cell.

15. The system of claim 13 wherein the auxiliary electrodes are formed within the solar cell.

16. The system of claim 13 wherein the auxiliary electrodes are formed in a top layer of the solar cell and within the solar cell.

17. An apparatus comprising:

a solar cell having a critical voltage range of open loop voltage, the solar cell including a main electrode and a plurality of auxiliary electrodes, the auxiliary electrodes formed in a top layer of the solar cell or within the solar cell; and

a circuit, connected to the solar cell, configured to provide a load to the solar cell in response to a voltage produced by the solar cell reaching the critical voltage range, the load being sufficient to prevent the voltage from exceeding the critical voltage range, the circuit to inject short pulses to the auxiliary electrodes to remove buildup of unipolar and dipolar charges in the solar cell, the circuitry integrated within the solar cell or connected externally to the solar cell.