WO2022260660A1

WO2022260660A1 - Customizable solar panel design and manufacturing

Info

Publication number: WO2022260660A1
Application number: PCT/US2021/036470
Authority: WO
Inventors: Robert Clinton LANE
Original assignee: Manaflex, Llc
Priority date: 2021-06-08
Filing date: 2021-06-08
Publication date: 2022-12-15

Abstract

A customizable solar panel design fabricated from multiple solar cell strings arranged in a formation. Each solar cell string is fabricated from a flexible printed circuit string produced from a reel-to-reel machine. A solar cell string includes an encapsulant layer, a solar cell layer, a top dielectric layer, an aluminum layer, a bottom dielectric layer. The aluminum layer is laser welded to the back of solar cells.

Description

CUSTOMIZABLE SOLAR PANEL DESIGN AND MANUFACTURING

CROSS-REFERENCE TO RELATED APPLICATIONS This application additionally claims priority to, and is a continuation-in-part of, U.S.

Patent Application No. 16/909,735, filed on June 23, 2020, now pending, which is hereby incorporated by reference in its entirety.

Although incorporated by reference in its entirety, no arguments or disclaimers made in the provisional applications apply to this non-provisional application. Any disclaimer that may have occurred is hereby expressly rescinded.

FIELD OF THE DISCLOSURE

The present disclosure relates to a solar panel technology, more particularly, a method of fabricating solar panels for various uses, including for electric vehicles.

BACKGROUND OF THE DISCLOSURE Currently the automotive market is transferring over from internal combustion engines to battery electric vehicles. Battery energy densities are achieving 150-200 Whr/kg with costs from $200 USD/Whr to $550 USD/Whr.

Currently there are semi-flexible solar panels of fixed shapes (e.g., a square shape) that can be laminated or integrated into the roof of a car. Others have put rigid solar panels on the rooftops of a house. Rigid solar panels require the use of an adapter truss and then panels are mounted thereon.

Rigid panels are too heavy for vehicles and they need a support structure. Since drag coefficient is important in vehicles these solutions are not favored. There is a continuing need for technologies that can further lower the cost of customizable solar panels for electric vehicles.

All referenced patents, applications and literatures are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. The disclosed embodiments may seek to satisfy one or more of the above-mentioned needs. Although the present embodiments may obviate one or more of the above-mentioned needs, it should be understood that some aspects of the embodiments might not necessarily obviate them.

BRIEF SUMMARY OF THE DISCLOSURE

In a general implementation, a method of fabricating a solar cell panel including the steps of producing a plurality of FPC (flexible printed circuit) strings; picking and placing a plurality of back side solar cells onto each of the plurality of FPC strings to create a plurality of solar cell strings; arranging the plurality of solar cell strings on a welding platform; electrically connecting the plurality of solar cell strings to result in a complete string.

In another aspect combinable with the general implementation, each of the plurality of FPC strings has a metal layer sandwiched between a top dielectric layer and a bottom dielectric layer. In another aspect combinable with the general implementation, each of the plurality of

FPC strings further includes a top PSA (pressure sensitive adhesive) layer or a thermoset adhesive layer disposed above the top dielectric layer. In another aspect combinable with the general implementation, the arranging step includes arranging the plurality of solar cell strings in a partially-overlapping configuration.

In another aspect combinable with the general implementation, wherein the partially overlapping configuration resembles a shingles configuration. In another aspect combinable with the general implementation, further including the step of encapsulating the plurality of back side solar cells by laminating an EVA (ethylene vinyl acetate) layer on top of the plurality of back side solar cells.

In another aspect combinable with the general implementation, wherein the laminating step is performed on a conveyered heat oven under vacuum. In another aspect combinable with the general implementation, further comprising welding a bus bar and a return tab to the metal layer.

In another aspect combinable with the general implementation, wherein the solar cell panel is flexible or semi-flexible.

In another aspect combinable with the general implementation, wherein the producing step is performed on a reel-to-reel machine.

In another aspect combinable with the general implementation, further comprising directly welding the metal layer to a plurality of contacts on the back side of each of the plurality of solar cells.

In another aspect combinable with the general implementation, further comprising welding a bussing FPC (flexible printed circuit) to the solar cell panel.

In another aspect combinable with the general implementation, wherein the metal layer is created by die cutting in a reel-to-reel machine.

In another aspect combinable with the general implementation, wherein the metal layer is created by laser ablation on the fly in a reel-to-reel machine. In another aspect combinable with the general implementation, chemical etching in combination with reel-to-reel fabrication of the FPC string can be implemented.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions.

Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination.

The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

It should be noted that the drawing figures may be in simplified form and might not be to precise scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directional terms such as top, bottom, left, right, up, down, over, above, below, beneath, rear, front, distal, and proximal are used with respect to the accompanying drawings. Such directional terms should not be construed to limit the scope of the embodiment in any manner.

Fig. 1 is an exploded view of an embodiment showing the various contemplated layers of the solar panel. Fig. 2 is a top view each of the layers in a contemplated FPC string, according to one aspect of the disclosure.

Fig. 3 shows the underside of three solar cell strings assembled together and welded, according to one aspect of the disclosure. Fig. 4 is a close-up view illustrating one contemplated metal layer pattern, according to one aspect of the disclosure.

Fig. 5 is a top view illustrating another contemplated metal layer pattern, according to one aspect of the disclosure.

Fig. 6 illustrates a shingle partial-overlap formation, according to one aspect of the disclosure.

Fig. 7 is a top view illustrating yet another contemplated metal layer pattern, according to one aspect of the disclosure.

Fig. 8 illustrates a fabrication process flow, according to one aspect of the disclosure.

Fig. 9 is an exploded view of a PCBA, according to one aspect of the disclosure. Fig. 10 is a perspective view of the PCA of Fig. 9, according to one aspect of the disclosure.

Fig. 11 illustrates a fabrications process flow, according to one aspect of the disclosure.

Fig. 12 illustrates a reel-to-reel fabrications process flow, according to one aspect of the disclosure.

The following call-out list of elements in the drawing can be a useful guide when referencing the elements of the drawing figures:

100 Solar Panel

110 Solar Cell String

112 Ultra-Transparent AR Glazed Polycarbonate 113 Top Encap sul ant 117A Positive Terminal Bus Bar 117B Negative Terminal Bus Bar

119 Backer Dielectric

120 Flexible Printed Circuit (FPC) String

121 PSA

122A Top Dielectric 122B Bottom Dielectric

123 Window

124 Metal Layer

125 Continuous Piece

127 Corner Connector 127 A Corner Connector 127B Corner Connector

128 Bussing Metal

129 Separation Gap

130 Bus Bar

132 Adj acent String Wei d Tab 134 Back Side Return Tab 140 Back Side Contact Solar Cells 140 Overlapping Region 142 Cell Weld Point

200 PCB Composite

201 Prepreg 222A Coverlay 222B Coverlay

224 Aluminum Traces

DETAILED DESCRIPTION OF THE EMBODIMENTS The different aspects of the various embodiments can now be better understood by turning to the following detailed description of the embodiments, which are presented as illustrated examples of the embodiments as defined in the claims. It is expressly understood that the embodiments as defined by the claims may be broader than the illustrated embodiments described below.

The inventor has discovered a way to fabricate back contact semi-flex solar panels customized to fit the specific shape of a roof of a car. The contemplated solar panel can be very light weight and can produce substantial energy for costs that are relatively low.

General Layout of the Contemplated Solar Panel

Referring now to Fig. 1, which illustrates an example of one contemplated embodiment of the solar panel 100. In this particular embodiment, the solar panel 100 can have an ultra-transparent anti-reflective glazed polycarbonate top layer 112. This layer can protect the solar cells 121 from impact as well as other environmental exposures. It is preferred to be UV stable.

Below the polycarbonate top layer 112 there can be a top encapsulant layer 113. An appropriate material can be used such as EVA (ethylene vinyl acetate). The encapsulant layer 113 can be laminated on top of the solar cells 140 to encapsulate the cells 140 and the top dielectric layer 122A

Under the top encapsulant layer 113 there can be a layer of solar cells 140. These can be any known solar cells such as SUNPPOWER solar cell (125mm monocrystalline 3.5W solar cells). In some embodiments, there can be back side contact solar cells. Other types of solar cells are also contemplated. Under the layer of solar cells 140 there can be a layer of FPC (flexible printed circuit) strings 120. Each FPC string 120 can be separately fabricated in a reel-to-reel machine, as will be described in more details later.

Each FPC string 120 can have a layer of PSA (pressure sensitive adhesive) 121. The layer of PSA 121 can be sufficiently thin to ensure any necessary welding and or embossment can be effectively done without having to deal with a gap that is too deep. In addition, this layer of PSA 121 can be pure PSA or a thermoset film with initial tack. This layer of PSA 121 can have a specific pattern such that during lamination the presence of air bubbles between the cells 140 and the top dielectric layer 122A is minimized. In some embodiments, the PSA layer 121 has a pattern that closely resembles the shape of each solar cell 140. In another embodiment, the PSA layer 121 has a pattern that leaves gaps, openings, and windows throughout the entire PSA layer 121.

Each FPC string 120 can have a metal layer 124. Any appropriate conductive material may be used such as aluminum. This metal layer 124 has the bussing metal 128 connecting from cell 140 to cell 140 and also has a large continuous metal piece 125 that allows for a return path to the other side of the string. Details of the metal layer 124 and its contemplated functions and patterns will be explained later.

The metal layer 124 can be sandwiched between a top dielectric layer 122A and a bottom dielectric layer 122B.

The top dielectric layer 122A can isolate the solar cells 140 from the metal layer 124 and can have through windows 123.

In some embodiments, there can be no bottom dielectric layer 122B.

Below the layer of FPC strings 120 there can be a layer of backer dielectric 119. This layer can serve as a backbone of the solar panel 100. In some embodiments, the material of the backer dielectric 119 is CTE-matched with the top polycarbonate 112. In one embodiment, the backer dielectric may be polycarbonate without an anti -reflective glaze. In some embodiments, the backer dielectric 119 can be a stiff, semi-flexible, or flexible material.

Extending from the metal layer there can be a positive terminal bus bar 117A and a negative terminal bus bar 117B. Fabrication of the FPC String

A FPC string 120 can be fabricated using any of the novel reel-to-reel FPC fabrication methods and devices disclosed in previously-filed U.S. patent application number 16/909,735, which is herein incorporated by reference in its entirety.

In some embodiments, the novel reel-to-reel machine can provide high throughput production of FPC strings 120 each ready to be further processed into a solar cell string 110, details of which will be described later.

A contemplated FPC string 120 can be a single-layer flexible printed circuit that consists of a top UV-stable dielectric coverlay 122A, an aluminum foil layer 124 below the top dielectric coverlay 122A, and a bottom UV-stable dielectric coverlay 122B disposed below the aluminum foil layer 124. The reel-to-reel machine can be fed, reel-to-reel, at various stages of the flow of production, an aluminum sheet 124, a top dielectric coverlay 122A, and a bottom dielectric coverlay 122B.

Metal Patterns

The aluminum sheet 124 can be laser-ablated on the fly using a laser scanner.

Various thickness of aluminum sheet 124 can be used. In one embodiment, 0.025 to 0.15 mm thick of aluminum is used. The laser scanner can ablate through the thickness of the aluminum sheet, thereby creating a separation gap 129 in between pieces of metal as shown in Fig. 4. The separation gap 129 can also be much larger and wider by first ablating an outline of a slug followed by removal of the slug using, for example, UV debonding sheets on the fly. When the slug is removed, the empty space once occupied by the slug becomes the separation gap 129.

In Figs. 1-4, the metal layer 124 has the same ablated patterns. In Fig. 5, the pattern is slightly different. Fig. 7 shows yet another contemplated pattern. In Fig. 4, the ablated separation gap 129 creates rectangular shaped pieces of bussing metal 128. The separation gap 129 physically separates the bussing metal 128 from the continuous piece 125. Likewise, the ablated separation gap 129 creates corner connector pieces 127, 127 A, and 127B. The separation gap 129 physically separates the corner connector pieces 127, 127 A, and 127B from the continuous piece 125. As will be described in more details later, the metal layer 124 can be embossed and welded onto the back contacts of the solar cells 140.

In some other embodiments, the metal pattern can be die cut. In yet other embodiments, the metal pattern can be die cut on the fly in the reel-to-reel machine.

Similarly, anywhere throughout this disclosure it is specifically contemplated that the laser ablation of a material (e.g., top and bottom dielectric layer 122A, 122B, PSA layer 121) can be replaced by die cutting.

In the novel reel-to-reel fabrication process, the top dielectric layer 122A is laminated onto the metal layer 124 in one step on the fly, and the bottom dielectric layer 122B is also laminated onto the metal layer 124 in one step on the fly. Referring to Fig. 2, the through windows 123 created (e.g., by die cut or by laser ablation) on the top and bottom dielectric layers 122A, 122B correlates with the physical locations of the corner connectors 127 and bussing metal 128. For example, while a bussing metal 128 may be laminated in place by the top dielectric layer 122 A, directly above the bussing metal 128 there can be two through windows 123 covering an area smaller than the area of the bussing metal 128. Directly below the bussing metal 128 there can be two through windows 123 having an area smaller than the area of the bussing metal 128.

In some embodiments, these windows 128 allows a laser scanner, at a later step, to directly weld the bussing metals 128 and comer connectors 127 onto the back connectors of solar cells 140. As disclosed in previously-filed U.S. patent application number 16/909,735, laser welding can also be done without through windows 123. Additionally, the bussing metals 128 and corner connectors 127 can be embossed first to ensure a better weld. The embossing steps can be done by a rotary die on the fly in the reel-to-reel machine, as described in previously-filed U.S. patent application number 16/909,735. As described above, the PSA layer 121 can be sufficiently think and can have a pattern. In Fig. 2, the PSA layer 121 provides open gaps directly above the through windows 123. The PSA layer 121 can be laminated to the top dielectric layer 122A reel-to-reel on the fly. This concludes the fabrication of the FPC string 120 using a reel-to-reel fabrication process. Fabrication of the Solar Cell String

A FPC string 120 goes through further process to result in a solar cell string.

Referring to Fig. 8, back side contact solar cells 140 can be vacuum-picked and placed on top of each FPC string 120.

A layer of EVA (ethylene vinyl acetate) 113 can next be placed on top of solar cells 140 and cured in a conveyered heat oven. Next, this string can be flipped over on a welding table exposing the underside of the string to a laser scanner.

The laser scanner can then weld certain specifically designed spots in the bussing metal 128 and comer connectors 127 onto the contacts on the solar cells 140. This concludes the fabrication of a solar cell string 110. It is specifically contemplated that in one embodiment, each FPC string 120 or each solar cell string 110 can have a width of one solar cell 140 (as shown in Fig. 2). In other embodiments, each FPC string 120 or each solar cell string 110 can have a width of multiple solar cells 140 (as shown in Fig. 5). The width of the FPC string 120 could be wide based on the specifications of the reel-to-reel machine. In one embodiment, the FPC string 120 could go up to 6 solar cells 140 wide by N number of solar cells 140 long.

Fabrication of a Solar Panel

Multiple pieces of solar cells strings 110 (they may or may not have the same length, and the length can be specifically tailored to fit the need of desired shape of solar panel) are then combined to make a single solar panel 100 of a desired shape.

Fig. 3 illustrates an example where three solar cell strings 110 (each having a width of one solar cell 140) are partially overlapped 140 in a shingled way (an array of continuous partial-overlaps, as in asphalt shingles, shown in Fig. 6) to connect the solar cell strings 110 as needed by the desired voltage stack. This arrangement, while on a welding table, is welded together in specific areas to complete the string. For example, positive terminal bus bar 117A can be welded on the edge of the solar cell string 110 to electrically connect to the continuous piece 125. A negative terminal bus bar 117B can be welded on another corner of the solar cell string 110 to electrically connect to the comer connectors 127 and bussing metal 128.

Fig. 3 shows the various bussing components. An adjacent string weld tab 132 can be welded to connect two adjacent solar cell strings 110 to complete the string. A back side return tab 134 can also be welded to complete the string. As an example, at the bottom of Fig. 3 there are indicated six cell weld points 142. The left three cell weld points 142 are welded onto the negative contacts of one solar cell 142. The right three cell weld points 142 are welded onto the positive contacts of an adjacent solar cell 142. The corresponding 127 corner connector and bussing metal 128 to which there weld points 142 are welded provide the electrical connection. Some solar cells have contacts on all four side of the square shape. The contemplated metal layer 124 pattern can allow accessibility of welding these contacts from all four sides the square pattern. This allows for simpler tabbing when strings are assembled for cells and return high voltage power. A close-up view of the square pattern is shown in Fig. 4. An alternative design is shown in Fig. 5. The design in Fig. 5 can be for a solar cell string 120 having a three-solar cell width. Here, one may manipulate placement of solar cells 124 and weld points 142 to complete a string.

The contemplated pattern allows for all three weld points to be welded that can enable better parallel bussing. This can be particularly useful for a solar panel having an irregular shape (e.g., roof of a bus requiring a large solar panel yet leaving large openings in the middle to accommodate vent openings in the roof).

In some embodiments, welding can be replaced by brazing or soldering depending on the circuit metal. For example, nickel plated copper or other metal or mixture of metal or metal alloy can be used. After multiple solar cell strings 110 are arranged and welded, a thermosettable adhesive (not shown) can be laminated onto the bottom side to seal off all exposed contacts, followed by a dielectric layer 119 (can be flexible or rigid by using a rigidizer backer).

There can be an optional layer of PSA as the bottommost layer so it can be used to mount to the roof of a car. Alternatively, the electric vehicle manufacturer could directly laminate the solar panel 100 with a thin backer directly to the roof of the car as well.

Additionally, a polycarbonate with anti -reflective coating can be added on to the top of the solar panel 100 to protect the cells from impact damage. This concludes the fabrication of a solar panel 100. This design and method for manufacturing allows manufacturing of any size and shape of solar panel without tooling while also enabling a prolonged and continuous fabrication using reel-to-reel fabrication technology.

The contemplated embodiments also leverage a unique bussing technology and welding technology disclosed in previously-filed U.S. patent application number 16/909,735, to enable ultra-high throughput at low initial capital cost to enable reel-to-reel manufacturing of single FPC strings 120. This will enable lower manufacturing costs than typical processes. Typical processes are conveyered stepped processes with soldering. Also, the contemplated bussing requires no pick and place and enables the string a return. Alternative Concept Using Prepreg

There may be instances where a rigid printed circuit board assembly can better serve the need of a particular application when customizing a solar panel 100. For example, it may be preferred that the solar panel 100 has a customized curvature and is rigid and not semi- flexible or flexible. This contemplated method relates to a design and a fabrication method to provide a rapid way to make a 3D surface part in a reel-to-reel mass production process that yields super high quality parts that can be used. The resulting product is a thermoplastic, fiberglass, or carbon fiber composite that has a circuit integrated into it in single or multilayers and can be thermal formed into complex 3D shapes. Referring now to Fig. 9, a prepreg material 201, which can be fiberglass, thermoplastic, carbon fiber and thermoplastic, pure thermoplastic, and other thermal formable materials, can be laminated to a circuit that is comprised of an aluminum trace 224 sandwiched between a top coverlay 222A and a bottom coverlay 222B. This stack can be layered as many times as needed. Then it can be thermal formed on a mold to produce an end product as shown in Fig. 10, an integrated circuit composite with a raised middle portion as an example.

The thermoplastic layer 201 can be thin and thermal formable. It can be applied to the rest of the stack via a reel-to-reel process, such as the process and devices disclosed in previously-filed U.S. patent application number 16/909,735.

Referring now to Figs. 11 and 12, two contemplated fabrication processes are provided.

This is in drastic contrast with currently known methods to make a PCBA that is labor intensive and costly. Currently known methods to make a PCBA include etching each layer on a prepreg and then stack them in a large vacuum thermal press followed by curing.

In a less preferred embodiment, a PCBA can be produced without the reel-to-reel process and can be done by gantry and by stations to make a thermal formable circuit.

Thus, specific embodiments and applications of solar panel have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the disclosed concepts herein.

The disclosed embodiments, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalent within the scope of the claims. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the embodiments. In addition, where the specification and claims refer to at least one of something selected from the group consisting of A, B, C .... and N, the text should be interpreted as requiring at least one element from the group which includes N, not A plus N, or B plus N, etc.

Claims

CLAIMS What is claimed is:

1. A method of fabricating a solar cell panel, the method comprising: producing a plurality of FPC (flexible printed circuit) strings; picking and placing a plurality of back side solar cells onto each of said plurality of FPC strings thereby creating a plurality of solar cell strings; arranging the plurality of solar cell strings on a welding platform; and electrically connecting the plurality of solar cell strings to result in a complete string; wherein each of the plurality of FPC strings has a metal layer sandwiched between a top dielectric layer and a bottom dielectric layer.

2. The method as recited in claim 1, wherein each of said plurality of FPC strings further comprises a top PSA (pressure sensitive adhesive) layer disposed above the top dielectric layer.

3. The method as recited in claim 1, wherein the arranging step including arranging the plurality of solar cell strings in a partially-overlapping configuration.

4. The method as recited in claim 3, wherein the partially overlapping configuration resembles a shingles configuration.

5. The method as recited in claim 1, encapsulating the plurality of back side solar cells by laminating an EVA (ethylene vinyl acetate) layer on top of the plurality of back side solar cells.

6. The method as recited in claim 5, wherein the laminating step is performed on a conveyered heat oven.

7. The method as recited in claim 1, wherein the electrically connecting step includes welding a bus bar and a return tab to the metal layer.

8 The method as recited in claim 1, wherein the solar cell panel is flexible or semi- flexible.

9. The method as recited in claim 1, wherein the producing step is performed on a reel- to-reel machine.

10. The method as recited in claim 1 further comprising directly welding the metal layer to a plurality of contacts on a back side of each of said plurality of solar cells.

11. The method as recited in claim 1 further comprising welding a bus bar or a bussing FPC (flexible printed circuit) to the solar cell panel.

12. The method as recited in claim 1, wherein the metal layer is created by die cutting in a reel-to-reel machine.

13. The method as recited in claim 1, wherein the metal layer is created by laser ablation on the fly in a reel-to-reel machine.