Solar cell sheet

Abstract

The application provides a solar cell, comprising two opposite surfaces, each surface having a plurality of grid lines extending along a first direction and arranged at intervals along a second direction; and a plurality of connecting areas arranged along the second direction, each connecting area having an adhesive and a conductive ring surrounding the adhesive, at least one grid line passing through the conductive ring. The solar cell of the application can simply and conveniently realize the connection of a main grid-free cell, and meanwhile, the consumption of silver paste in the preparation of the cell is reduced.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the field of photovoltaic technology, in particular to a solar cell. BACKGROUND

[0002] The solar cell with main grid is connected by the way of flat solder strip welding, wherein the solder strip is generally about 1.0-2mm in width, about 0.1-0.15mm in copper base thickness, and about 0.015-0.030mm in single-side plating thickness. In the connection, the solder is melted by high temperature, and then the solder strip is welded with the main grid on the cell. The way consumes a large amount of silver paste, and the preparation process is complex, and the formed cell causes a large light-shielding area.

[0003] As shown in Figure 1 a and 1b , the main grid cell in the prior art can effectively reduce the span between the main grids 11 by increasing the number of the main grids 11. However, the solder strip 12 is still welded with the cell through the main grids 11. In order to enhance the connection performance, the pad point, i.e. a large silver electrode point, is printed at the welding point, so as to improve the welding tension. Although the way of increasing the number of the main grids can partially reduce the amount of silver paste and the light-shielding area, the improvement is limited, and the welding method is inevitably used, and the cell is also prone to hidden cracks.

[0004] The best way to improve the preparation of the screen-printed main grid is to completely avoid the main grid. However, the technical difficulty of completely avoiding the main grid lies in how to realize the mutual series connection between the solar cell pieces. The prior art also provides a high-molecular adhesive film, which is first bonded with a wire, then placed on a cell, and finally laminated together. This technology can completely avoid the main grid, but the adhesive film needs a special structure, and needs to be bonded with the wire, and then fixed with the cell, which not only increases the process complexity but also increases the cost.

[0005] Therefore, there is still a lack of a perfect preparation process and structure for the main grid-free solar cell in the field, which can avoid the above problems. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a solar cell piece, which can simply and conveniently realize the connection of the main grid-free solar cell piece, and reduce the silver paste consumption in the preparation of the cell piece.

[0007] To solve the above technical problems, the application provides a solar cell, which comprises two opposite surfaces, each of which has a plurality of grid lines extending along a first direction and arranged along a second direction, and a plurality of connecting areas, each of which has an adhesive and a conductive ring surrounding the adhesive, and the conductive ring is in contact with at least one grid line.

[0008] In an embodiment of the application, the cell further comprises a plurality of solder strips, each of which crosses the plurality of grid lines and is fixedly bonded with the adhesive on at least two connecting areas, and each of the solder strips is in contact with the conductive ring and the grid lines other than the at least one grid line.

[0009] In an embodiment of the application, the plurality of connecting areas arranged along the second direction are sequentially arranged along the first direction.

[0010] In an embodiment of the application, the plurality of connecting areas arranged along the second direction are sequentially arranged along the first direction.

[0011] In an embodiment of the application, each of the plurality of connecting areas has the same shape.

[0012] In an embodiment of the application, at least some of the plurality of connecting areas have different shapes.

[0013] In an embodiment of the application, at least one of the plurality of connecting areas has a rectangular shape.

[0014] In an embodiment of the application, the at least one connecting area with a rectangular shape has opposite first and second sides, the first and second sides are respectively in contact with two grid lines, and the width and / or height of the first part of the first and second sides in contact with the two grid lines is greater than the width and / or height of the second part of the first and second sides not in contact with the two grid lines.

[0015] In an embodiment of the application, at least one of the plurality of connecting areas has a circular shape.

[0016] In an embodiment of the application, the edge of the connecting area is tangent to two grid lines.

[0017] In an embodiment of the application, the cross section of the solder strip comprises a circle, a rectangle and / or a triangle.

[0018] Compared with the prior art, the application has the following advantages:

[0019] The structure of the solar cell of the application can facilitate the electrical contact between the solder strip and the grid line, and reduce the consumption of silver paste during the preparation of the cell.

[0020] By avoiding the main grid structure, the risk of EL grid breakage can be reduced, and the shading area can be decreased, thereby increasing the reliability of the solar cells and improving the photoelectric conversion efficiency; and

[0021] Adjusting the width and / or height of some area grid lines and using solder strips with different cross-sectional shapes can effectively reduce light loss and power consumption. Attached Figure Description

[0022] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of the invention. In the drawings:

[0023] Figure 1 a and 1b This is a schematic diagram of a solar cell with a main grid.

[0024] Figures 2a-2c This is a schematic diagram of the structure of a solar cell according to the present invention;

[0025] Figures 3a-3c This is a schematic diagram of another type of solar cell according to the present invention;

[0026] Figure 4 This is a schematic diagram of another type of solar cell according to the present invention;

[0027] Figure 5 This is a partially enlarged schematic diagram of a solar cell according to the present invention; and

[0028] Figure 6 This is a partially enlarged schematic diagram of another type of solar cell according to the present invention. Detailed Implementation

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0030] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0031] The foregoing summary, as well as the following detailed description of the application, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the application, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the application is not limited to the embodiments shown in the drawings, but is capable of carrying out the application in various ways. In the drawings: FIG. 1 is a perspective view of a first embodiment of a device according to the present application;

[0032] In the description of the application, it will be understood that the orientation terms such as "front", "back", "up", "down", "left", "right", "lateral", "vertical", "horizontal", and "top", "bottom" and the like are made only for the purpose of convenience in describing the present application and simplifying the description, and do not indicate and imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the contour of the components themselves.

[0033] For the purpose of convenience, spatially relative terms, such as "above", "below", "top", "bottom", and the like, can be used herein for describing the spatial relationship between one device or feature to another device or feature as shown in the drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientations depicted in the drawings. For example, if a device is inverted in the drawings, a device described as "above" or "below" another device or structure would then be oriented "below" or "above" the other device or structure. Accordingly, the exemplary term "above" can encompass both an orientation of above and below. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Well-known structures have not been described in detail in order to avoid obscuring the present application. This application is not limited in scope by the format of the examples presented herein, which are intended as examples only.

[0034] In addition, it should be noted that the use of "first", "second", and / or the like herein is merely to distinguish one identifiable element from another, unless otherwise indicated, and is not otherwise intended to limit the scope of the present application. In addition, while the terms used in the present specification are selected from generally used terms which are currently widely used in consideration of functions in the art, some of the terms used herein can be created by the applicant himself or herself in his or her judgment. In this case, the detailed meanings of the terms used herein can be obviously understood by those skilled in the art in the corresponding technical field of the present application.

[0035] It will be understood that when a component is referred to as being "on" another component, "connected to" another component, "coupled to" another component, or "contacting" another component, it can be directly on, connected to, coupled to, or contacting the other component, or one or more intervening components can also be present. In contrast, when a component is referred to as being "directly on", "directly connected to", "directly coupled to", or "directly contacting" another component, there are no intervening components present. It will also be understood that, when a first component is referred to as being "electrically contacted" or "electrically coupled" to a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path can include capacitors, coupled inductors, and / or other components that allow current to flow, even if there is no direct contact between conductive components.

[0036] An embodiment of the present application provides a solar cell piece, which can simply and conveniently realize the connection of a main grid-free solar cell piece and reduce the consumption of silver paste during the preparation of the cell piece.

[0037] As shown in Figures 2a-2c , it is a structural schematic diagram of a solar cell piece 20 according to the present application. In order to more clearly show the structure of the solar cell piece, the front view and the plan view of the solar cell piece 20 before the solder strip 23 is adhered are shown in Figure 2a and Figure 2b , and the front view and the plan view of the solar cell piece 20 after the solder strip 23 is adhered are shown in Figure 2c , which shows the effect of the connection between two solar cell pieces through the solder strip 23. The structure of the solar cell piece 20 according to the present application will be described below with reference to Figures 2a-2c .

[0038] As shown in Figure 2a , the solar cell piece 20 has a thickness in the three-dimensional space, including two opposite upper and lower surfaces.

[0039] As shown in Figure 2bAs shown, each surface has multiple grid lines 21 extending along a first direction X and spaced apart along a second direction Y. The multiple grid lines 21 are adapted to provide a path for the solar panel 20 to carry photocurrent, that is, to conduct and transmit photocurrent through the multiple grid lines.

[0040] For example, in one embodiment of the present invention, the width of the gate line 21 can range from 0.1 μm to 100 μm, and the height of the gate line 21 can range from 1 to 50 μm. However, the present invention is not limited thereto.

[0041] Furthermore, each surface also has a plurality of connection regions 22 arranged along the second direction Y. However, the invention is not limited thereto, and in some other embodiments of the invention, the plurality of connection regions 22 may not be strictly arranged along the second direction Y.

[0042] For example, the area of ​​the connection region can range from 0.1 to 50 mm. 2 Preferably, several grid lines 21 pass through a connection area 22.

[0043] In such Figures 2a-2c In the illustrated embodiment, each connection region 22 has the same shape and is circular. Furthermore, the plurality of circular connection regions 22 arranged along the second direction Y are also arranged in an orderly manner along the first direction X. For example, this orderly arrangement means that the plurality of connection regions 22 are arranged in rows along the second direction, distributed in a straight line along the first direction, and each row has at least two connection regions. However, this invention does not... Figures 2a-2c The connection areas shown are limited to having the same shape and being arranged in an orderly manner along the first direction X. In other embodiments, multiple connection areas may have different shapes (such as rectangles or circles, or both rectangles and circles) and random arrangements, which will be described later.

[0044] In such Figures 2a-2c In the illustrated embodiment, each connection region also has an adhesive (not shown, located in the middle region of each connection region 22) and a conductive ring surrounding the adhesive (i.e., the edge of the connection region 22), with at least one grid line 21 passing through the conductive ring. This grid line passing through the conductive ring can conduct the photocurrent generated in the middle region of the conductive ring and transmit it to adjacent grid lines. Exemplarily, the adhesive can be a liquid adhesive or a solid adhesive; the present invention does not limit the form of the adhesive.

[0045] Specifically, in Figures 2a-2c In the diagram, the adhesive is not shown, but it can be understood that the adhesive is located on each connection area 22 and is used to adhere the solder ribbon 23 to the surface of the solar cell. Furthermore, the conductive ring represents the edge of the connection area 22. Within the area enclosed by the conductive ring, the adhesive is applied and the solder ribbon 23 is bonded, thus providing a defined area for the bonding of the solder ribbon 23 to the solar cell. In such a case...Figures 2a-2c In the embodiment shown, the circular conductive ring is in contact with two grid lines respectively at the outermost side of the circumference of the circular conductive ring, but the present application is not limited to the contact mode shown, and for example, the circular conductive ring can not be in contact with the grid lines in a tangential manner. Figures 2a-2c Figures 2a-2c

[0046] For better understanding of the structure of the connecting area in the solar cell of the present application, for example, for the preparation method of the grid line electrode, various methods in the field can be adopted, such as preparation by screen printing and sintering, preparation by electroplating, preparation by inkjet printing, etc., which functions to transport the carriers generated by the silicon substrate and to be collected on the solder ribbon. In some embodiments of the present application, screen printing is preferably used, for example, four screen printing is used.

[0047] Further, the preparation method of the connecting area includes reserving the shape of the connecting area on the mold when the grid line is prepared, so that the connecting area and the grid line can be integrally formed when the grid line is printed. After printing, the connecting area with a predetermined shape and quantity is formed on the specific area of the surface of the cell, and the edge of the connecting area has conductivity due to the same material as the grid line, thereby forming the conductive ring. However, the preparation method of the connecting area is not limited by the present application.

[0048] For example, the connecting area with a predetermined shape and quantity can be secondarily casted / printed on the surface of the formed cell which already has a plurality of grid lines, and a conductive material is used, so that a plurality of connecting area structures with conductive rings can also be formed. Since the preparation process of the grid line and the connecting area is not the focus of the present application, it will not be expanded here.

[0049] Further, as shown in Figure 2c On the basis of the above-mentioned cell structure, each solder ribbon 23 spans a plurality of grid lines 21 and is fixedly bonded with the adhesive on at least two connecting areas 22.

[0050] In the embodiment shown in Figures 2a-2c In the embodiment shown in

[0051] ​​In some embodiments of the present application, the cross section of the solder strip 23 can have different shapes, such as rectangular or circular, preferably, when the solder strip 23 with circular cross section is adopted, the light loss can be reduced and the efficiency of light spot conversion can be improved.

[0052] Generally, the number of solder strips is equal to the number of rows of connection regions, but the present application is not limited thereto. According to the structure of the above battery piece, the solder strip 23 can form electrical contact with the conductive ring (i.e. the edge of the connection region 22) and other grid lines not in contact with the conductive ring during the lamination process. Thus, a battery string with multiple battery pieces having the above structure can be further formed.

[0053] By the structure of the multiple battery pieces as shown in Figures 2a-2c , the connection between multiple busbar-free solar battery pieces can be simply and conveniently achieved. Further, the consumption of silver paste in the preparation of the battery pieces can be effectively saved.

[0054] Specifically, by adopting the structure of the solar battery piece of the present application, only the connection region needs to be provided and the solder strip is fixed on the surface of the battery piece by means of the adhesive, and can be integrally formed when the grid lines are prepared, thereby effectively saving the consumption of silver paste required in the preparation of the battery piece. For example, in an embodiment of the present application, by adopting the structure of the solar battery piece of the present application, the consumption of silver paste can be saved by about 70% compared with the same battery piece adopting the current busbar welding structure.

[0055] In addition, by adopting the structure of the connection region and fixing the solder strip by means of the adhesive, the risk of EL (Electroluminescence) grid breakage can be effectively reduced, and the reliability of the solar battery piece can be increased. At the same time, since there is no busbar structure, the light shielding area can also be effectively reduced, and for the same solar battery piece, the photoelectric conversion effect can be effectively improved.

[0056] Figures 3a-3c is another structure diagram of a solar battery piece 30 of the present application. The solar battery piece 30 also has multiple grid lines 31, multiple connection regions 32 and multiple solder strips 33, which are different from the embodiment shown in Figures 2a-2c in that the shape of the multiple connection regions 32 is rectangular.

[0057] Other details about the structure and preparation process of the solar battery piece 30 can be referred to the description of the embodiment shown in Figures 2a-2c above, which will not be described here.

[0058] In general, in the embodiments shown in Figures 2a-2c and Figures 3a-3cIn the shown embodiment, the connecting regions have the same shape, which is either circular or rectangular, and the connecting regions arranged along the second direction Y are also arranged in order along the first direction X. However, the present application is not limited to this.

[0059] As shown in Fig. 1, for example, Figure 4 In the shown embodiment, the solar cell 40 also has a plurality of grid lines arranged along the first direction X, a plurality of connecting regions 42 arranged along the second direction Y, and a plurality of solder strips 43 crossing the plurality of grid lines X.

[0060] In the shown embodiment, the connecting regions arranged along the second direction Y have different shapes and are not necessarily arranged in order along the first direction X. For example, the connecting regions arranged along the second direction Y are not necessarily arranged in order along the first direction X, such as the connecting regions arranged along the second direction Y are not necessarily arranged at the same interval along the first direction X. Further, in some other embodiments, the connecting regions are arranged in a more disordered manner, such as the second direction Y of some connecting regions is not necessarily perpendicular to the first direction X, as long as the solder strip can be connected to different solar cells along the second direction Y, which will not be described here. Figure 4 It can be understood that, in actual applications, in order to meet the requirements of different application scenarios or the limitations of the preparation process, different shapes can be selected and the connecting regions can be arranged in a disordered manner. As long as at least two connecting regions arranged along the second direction can provide a bonding position for the solder strip to fix the path of the solder strip on the surface of the cell and enable the solder strip to connect different cells, various modifications are within the spirit and scope of the present application.

[0061]

[0062] is a partial enlarged view of a solar cell 50 according to the present application, in which Figure 5 In order to more clearly illustrate the structure of the connecting region 52, the solder strip that should be covered on the connecting region 52 of the cell is omitted. Figure 5 As shown in Fig. 2, the outermost edge of the circumference of the connecting region 52 is in contact with and tangent to two grid lines 511 and 512 of the grid lines 51.

[0063] Figure 5 Similarly, is a partial enlarged view of another solar cell 60 according to the present application, in which

[0064] Similarly, in order to more clearly illustrate the structure of the connecting region 62, the solder strip that should be covered on the connecting region 62 of the cell is omitted. Figure 6 Figure 6 As shown in Fig. 3, the outermost edge of the circumference of the connecting region 62 is in contact with and tangent to two grid lines 611 and 612 of the grid lines 61.

[0065] As shown in Fig. 3, the outermost edge of the circumference of the connecting region 62 is in contact with and tangent to two grid lines 611 and 612 of the grid lines 61. Figure 6 ​As shown, taking one of the connection areas 62 on the battery cell 60 as an example, the connection area 62 has opposing first sides 621 and second sides 622, which respectively contact two of the plurality of grid lines 61, namely 611 and 612. Furthermore, the width and / or height of the first portion of the two grid lines 611 and 622 that contacts the first side 621 and the second side 622 is greater than the width and / or height of the second portion that does not contact the first side 621 and the second side 622.

[0066] Specifically, from Figure 6 As can be seen, the first side 621 and the second side 622 of the connecting area 62 partially contact the two gate lines. In the contacted portion, the width and / or height of the gate lines is greater than the height and / or width of the general gate lines at other points where there are no connecting areas (in...). Figure 6 This is reflected in the area where the side contacts the gate line (the lines are thicker), which can reduce the transmission resistance R of this contact part.

[0067] The principle is that the conductive rings (including the first side 621 and the second side 622) at the edge of the connection region 62 are conductive. Therefore, the photocurrent generated in the connection region 62 is led to the adjacent gate lines 611 and 612, causing the current in the two sections of gate lines 611 and 622 that are in contact with the conductive rings to increase. According to the current loss formula P... loss =I 2 As the current I increases, the transmission resistance R is reduced by increasing the height and / or width of the grid lines in the contact portion (i.e., increasing the cross-sectional area), thereby effectively reducing the power loss caused by the structure of the connection region 62 contacting its adjacent grid lines.

[0068] In one embodiment of the present invention, the adhesive material on the connection area includes conductive adhesive, OCA adhesive (Optically Clear Adhesive), and UV photosensitive adhesive. Exemplarily, the adhesive can be in solid, film-like, or liquid form. Specifically, to facilitate the fabrication of the solar cell, the adhesive can possess advantages such as rapid curing, high temperature resistance, UV resistance, and good transparency. Any adhesive with the same properties that can perform an adhesive function falls within the spirit and scope of the present invention.

[0069] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0070] Also, the use of "a" or "an" to describe an element of the application is merely taken to mean "one or more" in some embodiments, unless otherwise indicated. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", or "includes" and / or "including" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0071] Similarly, it is to be noticed that the term coupled, when used in the present specification, is not limited to the case where a connection between the entities is directly made, but it is also intended to cover the case where the connection is made through another entity.

[0072] Some embodiments use numerical ranges to describe quantities of components, attributes, etc. It should be understood that such numerical ranges described in the embodiments are, in some examples, modified by the word "about". Unless otherwise indicated, "about" indicates that a value can vary by ±20%. Accordingly, numerical parameters such as those for quantities, percentages, and so forth, are approximations. Although the numerical ranges and parameters setting forth the broad scope of these embodiments are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values set forth in the specific examples are provided to be as precise as reasonably possible. However, some variations may occur depending on the choice of device used in the experiments.

[0073] While the application has been described with reference to the currently preferred embodiments, those skilled in the art will recognize that changes can be made within the spirit of the application, and it is intended to include all changes coming within the meaning and equivalences of the claims.

Claims

1. A solar cell piece comprising two opposite surfaces, characterized in that, Each surface has: a plurality of gate lines extending in a first direction and spaced apart in a second direction; a plurality of connection regions, each connection region having an adhesive and a conductive ring surrounding the adhesive, at least one gate line passing through the conductive ring, wherein at least one connection region of the plurality of connection regions has a shape comprising a rectangle, when the connection region is a rectangle, the at least one connection region has opposite first and second side edges in contact with two gate lines, respectively; or at least one connection region of the plurality of connection regions has a shape comprising a circle, when the connection region is a circle, the conductive ring is in contact with two gate lines at the outermost side of its circumference, respectively; and a plurality of solder strips, each solder strip spanning the plurality of gate lines and fixedly bonded to the adhesive on at least two connection regions, each solder strip being in contact with the conductive ring and gate lines other than the at least one gate line.

2. The solar cell of claim 1, wherein, The cross-section of the solder strip comprises a circle, a rectangle and / or a triangle.

3. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The plurality of connection regions are arranged in order or disorder in the first direction.

4. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The plurality of connection regions are arranged in a straight line in the second direction.

5. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. Each connection region has the same shape.

6. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. At least some of the plurality of connection regions have different shapes.

7. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. The width and / or height of a first portion of the first and second side edges in contact with the two gate lines is greater than the width and / or height of a second portion not in contact with the first and second side edges.

8. The solar cell of claim 1, wherein the first and second electrodes are formed of a material selected from the group consisting of silver, aluminum, and copper. When the connection region is a circle, the edge of the connection region is tangent to the two gate lines.

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