Patent Grant
8513095
The present invention relates generally to solar energy techniques. In particular, the present invention provides a method and resulting device fabricated from a plurality of photovoltaic regions provided within a photovoltaic material. More particularly, embodiments according to the present invention provide a method and resulting device for separating photovoltaic strips from a photovoltaic material. Merely by way of example, embodiments according to the present invention has been applied to solar panels, commonly termed modules, but it would be recognized that the invention has a much broader range of applicability.
As the population of the world increases, industrial expansion has lead to an equally large consumption of energy. Energy often comes from fossil fuels, including coal and oil, hydroelectric plants, nuclear sources, and others. As merely an example, the International Energy Agency projects further increases in oil consumption, with developing nations such as China and India accounting for most of the increase. Almost every element of our daily lives depends, in part, on oil, which is becoming increasingly scarce. As time further progresses, an era of “cheap” and plentiful oil is coming to an end. Accordingly, other and alternative sources of energy have been developed.
Concurrent with oil, we have also relied upon other very useful sources of energy such as hydroelectric, nuclear, and the like to provide our electricity needs. As an example, most of our conventional electricity requirements for home and business use comes from turbines run on coal or other forms of fossil fuel, nuclear power generation plants, and hydroelectric plants, as well as other forms of renewable energy. Often times, home and business use of electrical power has been stable and widespread.
Most importantly, much if not all of the useful energy found on the Earth comes from our sun. Generally all common plant life on the Earth achieves life using photosynthesis processes from sun light. Fossil fuels such as oil were also developed from biological materials derived from energy associated with the sun. For human beings including “sun worshipers,” sunlight has been essential. For life on the planet Earth, the sun has been our most important energy source and fuel for modern day solar energy.
Solar energy possesses many characteristics that are very desirable! Solar energy is renewable, clean, abundant, and often widespread. Certain technologies developed often capture solar energy, concentrate it, store it, and convert it into other useful forms of energy.
Solar panels have been developed to convert sunlight into energy. As merely an example, solar thermal panels often convert electromagnetic radiation from the sun into thermal energy for heating homes, running certain industrial processes, or driving high grade turbines to generate electricity. As another example, solar photovoltaic panels convert sunlight directly into electricity for a variety of applications. Solar panels are generally composed of an array of solar cells, which are interconnected to each other. The cells are often arranged in series and/or parallel groups of cells in series. Accordingly, solar panels have great potential to benefit our nation, security, and human users. They can even diversify our energy requirements and reduce the world's dependence on oil and other potentially detrimental sources of energy.
Although solar panels have been used successful for certain applications, there are still certain limitations. Solar cells are often costly. Depending upon the geographic region, there are often financial subsidies from governmental entities for purchasing solar panels, which often cannot compete with the direct purchase of electricity from public power companies. Additionally, the panels are often composed of silicon bearing wafer materials. Such wafer materials are often costly and difficult to manufacture efficiently on a large scale. Availability of solar panels is also somewhat scarce. That is, solar panels are often difficult to find and purchase from limited sources of photovoltaic silicon bearing materials. These and other limitations are described throughout the present specification, and may be described in more detail below.
From the above, it is seen that techniques for improving fabricating solar devices is highly desirable.
According to embodiments of the present invention, a method and a system to separate photovoltaic strips from a photovoltaic material is provided. More particularly, embodiments according to the present provide a method and a system to separate photovoltaic strips from the photovoltaic material that are free from defects in the P-N junction. In a specific embodiment, each of the photovoltaic strips is further assembled into P-V modules and P-V panels. But it would be recognized that embodiments according to the present invention have a much broader range of applicability. For example, the method can be applied to semiconductor device packaging among others.
In a specific embodiment, a method for manufacturing solar strips is provided. The method includes providing a photovoltaic material. The photovoltaic material includes a back side region and a front side surface. In a specific embodiment, the photovoltaic material includes a plurality of photovoltaic strip regions numbered from 1 through N, N being an integer greater than 5 in a preferred embodiment. In a specific embodiment, each of the photovoltaic strip regions is separated by a scribe region provided in the front side surface of the photovoltaic material. For example, the scribe region may be provided in a portion of the photovoltaic material using a partial cut through a thickness in the front side surface of the photovoltaic material in a specific embodiment. According to an embodiment, the depth of the partial cut may range from a range of 35% to 95% of the depth of the photovoltaic material. The method includes supporting a first portion of the photovoltaic material and allowing at least a second portion of the photovoltaic material unsupported. The method includes applying a predetermined force along a length of one or more of the photovoltaic strip regions that remains unsupported. The force causes the one or more photovoltaic strip regions to be separated and removed from the supported photovoltaic material in a specific embodiment.
Numerous benefits can be achieved by ways of the present invention over existing techniques. In particular, embodiments according to the present invention use a method and a system that provide photovoltaic strips to further assembled into solar modules and photovoltaic systems. In a preferred embodiment, the method provides a scribe region in a portion of the photovoltaic material to allow for the separation of one or more photovoltaic strips from the photovoltaic material. Preferably, each of the photovoltaic strip as well as the remaining photovoltaic material are free from defects.
Depending on the embodiment, one or more of these benefits may be achieved. These and other benefits are described throughout the present specification and particularly below.
According to embodiments of the present invention, a method and a system to separate photovoltaic strips from a scribed photovoltaic material is provided. Conventional method of separating devices, for example, in semiconductor industry can include a sawing process, or a laser cut process, among others. Such processes invariably cause kerf loss and possibly cracking and chipping in the scribed photovoltaic material. In addition, such process may cause delamination of conductor layer(s) from a scribed photovoltaic material and are not adequate or cost effective in separating scribed photovoltaic materials. Accordingly, embodiments according to the present invention provide a method and a system to separate photovoltaic strips from the scribed photovoltaic material that are free from defects in, for example, P-N junction, interface regions (e.g., contact regions), and others. Preferably the method provides a cost effective way to provide photovoltaic strips to be further assembled into P-V modules and P-V panels.
In a specific embodiment, a method of separating a photovoltaic strip from a scribed photovoltaic material may be outlined as follow:
1. Provide scribed photovoltaic material, where the scribed photovoltaic material includes a front side surface, a back side region, and a plurality of photovoltaic strip regions separated by a plurality of scribe regions;
2. Support a first portion of the scribed photovoltaic material and leaving a second portion of the scribed photovoltaic material unsupported, where the second portion separated from the first portion by a scribe region and where the second portion includes at least one photovoltaic strip region;
3. Apply a force (for example, a shear force, a breaking force) along the length of the second (unsupported) portion, the length being parallel to the length of the scribe region, and causing the second portion to be separated from the first portion;
4. Maneuver and align the scribed photovoltaic material such that a portion of the remaining scribed photovoltaic material is supported and a portion of the remaining scribed photovoltaic material is left unsupported.
5. Remove the separated photovoltaic regions for further processing;
6. Repeat the above steps until all the rest of the scribed photovoltaic material has been consumed;
7. Perform other steps as needed.
The above sequence of steps provides a method for separating photovoltaic strips in a scribed photovoltaic material, where the separate strips can be assembled into photovoltaic modules.
To process and separate the plurality of photovoltaic strips, the scribed photovoltaic material is maneuvered and aligned such that a first portion of the scribed photovoltaic material is provided on a support while a second portion is left unsupported. The second portion is separated from the first by a scribe region and can include one or more photovoltaic strips. The second portion of the scribed photovoltaic material is subjected to a force along a direction parallel to the length of one of the photovoltaic strips or scribe regions. The force causes the second portion to be separated from the first portion of the scribed photovoltaic material. The separated scribed photovoltaic material is then removed for further processing. The remaining portions of the original scribed photovoltaic material on the supporting material is subjected to the above separation steps to detach further a plurality of separated scribed photovoltaic materials. Other alternatives may also be provided where steps are added, re-ordered, removed, or substituted without departing from the scope of the claims herein. Further details of the present method can be found throughout the present specification and more particularly below.
Scribed photovoltaic material 200 may also include conductor regions 212 overlying portions of front surface region 202. Conductor regions 212 may be provided using a suitable metal layer such as a silver alloy, an aluminum alloy, or a combination. Each photovoltaic strip region includes at least one P-N junction 214. According to one embodiment, each strip region one P-N junction in a portion of the thickness of the scribed photovoltaic material that divides each photovoltaic strip along the length the strip. According to another embodiment, each strip region one P-N junction in a portion of the thickness of the scribed photovoltaic material that divides each photovoltaic strip along the width the strip. A passivation layer 216 is provided overlying back surface region 204 of a scribed photovoltaic material. An exemplary passivation layer 216 include materials such as silicon nitride. Depending on the embodiment, there can be other variations, modifications, and alternatives.
An exemplary force applied along the length of a photovoltaic strip causes the unsupported one or more photovoltaic strips to be separated from the scribed photovoltaic material alone the length of a scribe region, as described above. In an embodiment, the separation of the one or more photovoltaic strips from the scribed photovoltaic material occur along a scribed region. The separation may also occur along a crystal plane within the scribed photovoltaic material. In a specific embodiment, the force is applied within a predetermined time period. The predetermined time period may range from a first value to a second value capable for efficient manufacturing according to a specific embodiment. The velocity of hammer-like device applying the predetermined force may range from a first value to a second value, but no greater than an amount capable of causing damage to any of the strips according to a specific embodiment
According to an embodiment, additional processes may the separation process. According to an embodiment, Nitrogen is applied to cold freeze the scribed photovoltaic material before the pre-determined force is applied. According to another embodiment, a flow of Oxygen may also be applied. According to yet another embodiment, a strong water flow may be provided over the scribed photovoltaic material.
According to an embodiment, the force applied the scribed photovoltaic material causes a clean and complete separation of the unsupported photovoltaic strip regions from the scribed photovoltaic material. The one or more conductor regions, the photovoltaic strip regions, and the P-N junctions are also not damaged during the separation process. Additionally, interface region such as that between the conductor material and the scribed photovoltaic material also remains intact and undamaged. In an embodiment, the force applied also causes the one or more separated photovoltaic strips to travel along oblique side surface 608. According to an embodiment, the detached photovoltaic strips is moved along oblique side surface 608 by gravity. The detached photovoltaic strips preferably moves in a right-side-up position, without flipping.
A hammer-like device is next brought to apply a force against the second portion of the scribed photovoltaic material. According to an embodiment, the force contains a component 908 normal to the plane of the scribed photovoltaic material. The normal component causes the unsupported portion to shear away and separate from the supported portion. According to a specific embodiment, the force also includes a tangential component 910. The tangential component pulls the second (unsupported) portion of the scribed photovoltaic material from the first (supported) portion of the scribed photovoltaic material along the plane of the scribed photovoltaic material. Care is taken to ensure that the tangential component does not push the second (unsupported) portion of the scribed photovoltaic material from the first (supported) portion of the scribed photovoltaic material. Such a pushing force may cause the photovoltaic material to crack or chip. The separated portion contains a plurality of photovoltaic strips and are transported 912 along the oblique or incline face 907 of support member 905. The separated portion preferably is moved along the incline in an upright position without flipping.
While the above is a full description of specific embodiments, various modifications, alternatives, and equivalents may be used. The above has been described using a selected sequence of steps. It is noted that any combination of any elements of steps described as well as others may be used. Additionally, certain steps may be added and/or combined, and/or eliminated depending upon the embodiment. For example, the clamping process may be modified to include other mechanism to prevent shattering of the scribed photovoltaic material. In addition, the force to cause separation may be provided by applying other distributed force along the photovoltaic strip region. Other ways to separate the photovoltaic strip region from the scribed photovoltaic material may include a cold freeze, a shearing force or an air knife depending on the embodiment. The number of photovoltaic strips in the photovoltaic strip regions to be separated may also vary depending on the embodiment. Of course there can be other variations, modifications, and alternatives. Therefore the above description and illustrations should not be taken as limiting the scope of the present invention which is defined by the appended claims.
This application claims priority to U.S. Provisional Patent Application No. 60/969,793, filed Sep. 4, 2007, commonly assigned, incorporated herein by reference for all purposes.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3700714 | Hamilton et al. | Oct 1972 | A |
| 4029519 | Schertz et al. | Jun 1977 | A |
| 4091798 | Selcuk | May 1978 | A |
| 4097308 | Klein et al. | Jun 1978 | A |
| 4118249 | Graven et al. | Oct 1978 | A |
| 4122833 | Selcuk | Oct 1978 | A |
| 4143234 | Johnson et al. | Mar 1979 | A |
| 4166917 | Dorfeld et al. | Sep 1979 | A |
| 4170507 | Keeling et al. | Oct 1979 | A |
| 4291191 | Dahlberg | Sep 1981 | A |
| 4293192 | Bronstein | Oct 1981 | A |
| 4295463 | Citron | Oct 1981 | A |
| 4333447 | Lemrow et al. | Jun 1982 | A |
| 4361136 | Huang | Nov 1982 | A |
| 4404422 | Green et al. | Sep 1983 | A |
| 4440153 | Melchior | Apr 1984 | A |
| 4449514 | Selcuk | May 1984 | A |
| 4454371 | Folino | Jun 1984 | A |
| 4457297 | Sobczak et al. | Jul 1984 | A |
| 4463749 | Sobczak et al. | Aug 1984 | A |
| 4511618 | Duchene et al. | Apr 1985 | A |
| 4571812 | Gee | Feb 1986 | A |
| 4589191 | Green et al. | May 1986 | A |
| 4683154 | Benson et al. | Jul 1987 | A |
| 4691994 | Tveryanovich | Sep 1987 | A |
| 4848319 | Appeldorn | Jul 1989 | A |
| 4863224 | Tveryanovich | Sep 1989 | A |
| 4964713 | Goetzberger | Oct 1990 | A |
| 4999059 | Bagno | Mar 1991 | A |
| 5080725 | Green et al. | Jan 1992 | A |
| 5118361 | Fraas et al. | Jun 1992 | A |
| 5153780 | Jorgensen et al. | Oct 1992 | A |
| 5167724 | Chiang | Dec 1992 | A |
| 5174275 | Holland | Dec 1992 | A |
| 5240510 | Goldade et al. | Aug 1993 | A |
| 5245985 | Holland | Sep 1993 | A |
| 5261970 | Landis et al. | Nov 1993 | A |
| 5344496 | Stern et al. | Sep 1994 | A |
| 5356488 | Hezel | Oct 1994 | A |
| 5365920 | Lechner | Nov 1994 | A |
| 5395070 | Wilk | Mar 1995 | A |
| 5449626 | Hezel | Sep 1995 | A |
| 5460659 | Krut | Oct 1995 | A |
| 5466301 | Hammerbacher et al. | Nov 1995 | A |
| 5498297 | O'Neill et al. | Mar 1996 | A |
| 5517339 | Riccobono et al. | May 1996 | A |
| 5529054 | Shoen | Jun 1996 | A |
| 5542409 | Sampayo | Aug 1996 | A |
| 5564411 | Gerics | Oct 1996 | A |
| 5660644 | Clemens | Aug 1997 | A |
| 5707459 | Itoyama et al. | Jan 1998 | A |
| 5735966 | Luch | Apr 1998 | A |
| 5782993 | Ponewash | Jul 1998 | A |
| 5787878 | Ratliff, Jr. | Aug 1998 | A |
| 5790304 | Sanders et al. | Aug 1998 | A |
| 5851309 | Kousa | Dec 1998 | A |
| 5865905 | Clemens | Feb 1999 | A |
| 5877874 | Rosenberg | Mar 1999 | A |
| 5882434 | Horne | Mar 1999 | A |
| 5936777 | Dempewolf | Aug 1999 | A |
| 5959787 | Fairbanks | Sep 1999 | A |
| 5964216 | Hoffschmidt et al. | Oct 1999 | A |
| 5994230 | Huntoon | Nov 1999 | A |
| 6008449 | Cole | Dec 1999 | A |
| 6049035 | Tsuri et al. | Apr 2000 | A |
| 6057505 | Ortabasi | May 2000 | A |
| 6091017 | Stern | Jul 2000 | A |
| 6091020 | Fairbanks et al. | Jul 2000 | A |
| 6107564 | Aguilera et al. | Aug 2000 | A |
| 6118067 | Lashley et al. | Sep 2000 | A |
| 6134784 | Carrie et al. | Oct 2000 | A |
| 6167724 | Pozivil | Jan 2001 | B1 |
| 6274402 | Verlinden et al. | Aug 2001 | B1 |
| 6274860 | Rosenberg | Aug 2001 | B1 |
| 6294723 | Uematsu et al. | Sep 2001 | B2 |
| 6309901 | Tahon et al. | Oct 2001 | B1 |
| 6323415 | Uematsu et al. | Nov 2001 | B1 |
| 6333457 | Mulligan et al. | Dec 2001 | B1 |
| 6337283 | Verlinden et al. | Jan 2002 | B1 |
| 6387726 | Verlinden et al. | May 2002 | B1 |
| 6423568 | Verlinden et al. | Jul 2002 | B1 |
| 6429037 | Wenham et al. | Aug 2002 | B1 |
| 6433913 | Bauer et al. | Aug 2002 | B1 |
| 6440769 | Peumans et al. | Aug 2002 | B2 |
| 6479744 | Tsuzuki et al. | Nov 2002 | B1 |
| 6528716 | Collette et al. | Mar 2003 | B2 |
| 6528718 | Yoda et al. | Mar 2003 | B2 |
| 6583032 | Ishikawa et al. | Jun 2003 | B1 |
| 6612705 | Davidson et al. | Sep 2003 | B1 |
| 6619282 | Murtha | Sep 2003 | B1 |
| 6620995 | Vasylyev et al. | Sep 2003 | B2 |
| 6666207 | Arkas et al. | Dec 2003 | B1 |
| 6676263 | Winston | Jan 2004 | B2 |
| 6700054 | Cherney et al. | Mar 2004 | B2 |
| 6700055 | Barone | Mar 2004 | B2 |
| 6804062 | Atwater et al. | Oct 2004 | B2 |
| 6843573 | Rabinowitz et al. | Jan 2005 | B2 |
| 6849797 | Koyanagi et al. | Feb 2005 | B2 |
| 20020007845 | Collette et al. | Jan 2002 | A1 |
| 20020018308 | Winston | Feb 2002 | A1 |
| 20020075579 | Vasylyev et al. | Jun 2002 | A1 |
| 20020139414 | Vasylyev et al. | Oct 2002 | A1 |
| 20030015233 | Barone | Jan 2003 | A1 |
| 20030037814 | Cohen et al. | Feb 2003 | A1 |
| 20030081333 | Winston | May 2003 | A1 |
| 20030095340 | Atwater et al. | May 2003 | A1 |
| 20030121542 | Harneit et al. | Jul 2003 | A1 |
| 20030156337 | Davidson et al. | Aug 2003 | A1 |
| 20030201007 | Fraas et al. | Oct 2003 | A1 |
| 20040016454 | Murphy et al. | Jan 2004 | A1 |
| 20040021964 | Rabinowitz et al. | Feb 2004 | A1 |
| 20040084077 | Aylaian | May 2004 | A1 |
| 20040097012 | Weber et al. | May 2004 | A1 |
| 20040123895 | Kardauskas et al. | Jul 2004 | A1 |
| 20040134531 | Habraken et al. | Jul 2004 | A1 |
| 20040194820 | Barone | Oct 2004 | A1 |
| 20040243364 | Wendelin et al. | Dec 2004 | A1 |
| 20040246605 | Stiles et al. | Dec 2004 | A1 |
| 20050070059 | Blakers et al. | Mar 2005 | A1 |
| 20050081908 | Stewart | Apr 2005 | A1 |
| 20050081909 | Paull | Apr 2005 | A1 |
| 20050087294 | Rabinowitz | Apr 2005 | A1 |
| 20060054211 | Meyers | Mar 2006 | A1 |
| 20070099396 | Hirai et al. | May 2007 | A1 |
| 20080070378 | Yeo | Mar 2008 | A1 |
| 20080223429 | Everett et al. | Sep 2008 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 60969793 | Sep 2007 | US |
