Back contact battery cell, battery module and photovoltaic system

Abstract

The present application is suitable for the technical field of solar batteries, and provides a back contact battery cell, a battery module and a photovoltaic system. The back contact battery cell comprises a silicon wafer and a plurality of electrode structures. A first electrode area, a second electrode area and a non-electrode area are formed on a backlight surface of the silicon wafer, the non-electrode area being located between the first electrode area and the second electrode area; the electrode structure located in the first electrode area comprises a first boundary gate line, and the electrode structure located in the second electrode area comprises a second boundary gate line, the polarities of the first boundary gate line and the second boundary gate line being opposite to each other; and the disconnection rates of the first boundary gate line and the second boundary gate line both being less than or equal to 5%. Thus, the potential difference of the non-electrode area can be as low as possible, such that areas on two sides of the non-electrode area can independently work in the state of cut cells when the non-electrode area is not physically cut, thereby achieving the same effect as the non-electrode area being physically cut.

Description

Back contact cell, cell assembly and photovoltaic system

[0001] This application claims priority to the Chinese patent application with application number 2023118006868, entitled “A back-contact cell, cell module and photovoltaic system”, filed with the Patent Office of China on December 25, 2023, and the Chinese patent application with application number 2023235502991, entitled “A back-contact cell, cell module and photovoltaic system”, filed with the Patent Office of China on December 25, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the technical field of solar cells, and in particular relates to a back-contact cell, a cell assembly and a photovoltaic system. Background Art

[0003] Solar cells are a sustainable, clean energy source that utilize the photovoltaic effect of a semiconductor pn junction to convert sunlight into electricity. A solar cell with both polarity grid lines formed on the back of the cell is called a back-contact cell.

[0004] In the related art, it is usually necessary to cut the entire back-contact solar cell into multiple solar cells and then electrically connect the multiple solar cells. However, this is a cumbersome slicing process and requires equipment to be set up for the slicing process, resulting in high costs. Technical issues

[0005] Based on this, how to design back-contact solar cells to reduce costs has become an urgent problem to be solved. Technical Solutions

[0006] The present application provides a back-contact cell, a cell assembly, and a photovoltaic system, aiming to solve the problem of how to design back-contact cells to reduce costs.

[0007] The back-contact cell provided in the present application includes a silicon wafer and several electrode structures. The backlight surface of the silicon wafer forms a first electrode area, a second electrode area and a non-electrode area. The non-electrode area is located between the first electrode area and the second electrode area. The electrode structure located in the first electrode area includes a first boundary grid line, and the electrode structure located in the second electrode area includes a second boundary grid line. The polarity of the first boundary grid line and the second boundary grid line are opposite, and the disconnection rate of the first boundary grid line and the second boundary grid line are both less than or equal to 5%.

[0008] The battery assembly provided in the present application includes any of the above-mentioned back-contact battery cells.

[0009] The photovoltaic system provided in this application includes any of the above-mentioned battery components. Beneficial effects

[0010] In the back-contact cell, cell assembly, and photovoltaic system of the embodiments of the present application, since the boundary grid lines of the two electrode structures have opposite polarities and the disconnection rate is less than or equal to 5%, the potential difference in the non-electrode area can be kept as low as possible. As a result, without physically cutting the non-electrode area, the areas on both sides of the non-electrode area can operate independently in a state close to that of a sliced ​​cell, achieving an effect similar to that of physically cutting the non-electrode area. In this way, while achieving an effect similar to that of slicing, the slicing step and slicing equipment can be omitted, reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic structural diagram of a back-contact cell according to an embodiment of the present application;

[0012] FIG2 is an enlarged schematic diagram of portion A of the back contact cell of FIG1 ;

[0013] FIG3 is a schematic structural diagram of a back-contact cell according to an embodiment of the present application;

[0014] FIG4 is an enlarged schematic diagram of portion B of the back contact cell of FIG3 ;

[0015] FIG5 is a schematic structural diagram of a back-contact cell according to an embodiment of the present application;

[0016] FIG6 is an enlarged schematic diagram of portion C of the back contact cell of FIG5 ;

[0017] FIG7 is a schematic diagram of a partial structure of a back contact cell according to an embodiment of the present application;

[0018] FIG8 is a schematic diagram of a partial structure of a back contact cell according to an embodiment of the present application;

[0019] FIG9 is a schematic diagram showing the connection between two adjacent back-contact solar cells according to an embodiment of the present application;

[0020] Description of main component symbols:

[0021] Back contact cell 100, silicon wafer 10, first electrode area 11, second electrode area 12, non-electrode area 13, first boundary grid line 21, second boundary grid line 22, first sub-grid 231, second sub-grid 232, first main grid 241, second main grid 242, width d of non-electrode area, conductive member 30, pad 40, electrical connector 200. Modes for Carrying Out the Invention

[0022] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application.

[0023] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0026] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0027] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use scenarios of other materials.

[0028] In this application, because the boundary grid lines of the two electrode structures have opposite polarities and the disconnection rate is less than or equal to 5%, the potential difference in the non-electrode area can be kept as low as possible. As a result, without physically cutting the non-electrode area, the areas on both sides of the non-electrode area can operate independently in a state close to that of a sliced ​​battery, achieving an effect similar to that of physically cutting the non-electrode area. In this way, while achieving an effect similar to that of slicing, the slicing step and slicing equipment can be omitted, reducing costs.

[0029] Example 1

[0030] Please refer to Figures 1, 2, 3, 4, 5 and 6. The back-contact cell 100 of an embodiment of the present application includes a silicon wafer 10 and several electrode structures. The backlight surface of the silicon wafer 10 forms a first electrode area 11, a second electrode area 12 and a non-electrode area 13. The non-electrode area 13 is located between the first electrode area 11 and the second electrode area 12. The electrode structure located in the first electrode area 11 includes a first boundary grid line 21, and the electrode structure located in the second electrode area 12 includes a second boundary grid line 22. The polarities of the first boundary grid line 21 and the second boundary grid line 22 are opposite, and the disconnection rates of the first boundary grid line 21 and the second boundary grid line 22 are both less than or equal to 5%.

[0031] In the back-contact cell 100 of the present embodiment, since the boundary grid lines of the two electrode structures have opposite polarities and the disconnection rate is less than or equal to 5%, the potential difference in the non-electrode region 13 can be kept as low as possible. As a result, without physically cutting the non-electrode region 13, the areas on both sides of the non-electrode region 13 can operate independently in a state similar to that of a sliced ​​cell, achieving an effect similar to that of physically cutting the non-electrode region 13. This can achieve an effect similar to that of slicing while eliminating the slicing step and slicing equipment, reducing costs.

[0032] It can be understood that if the polarity of the first boundary grid line 21 and the second boundary grid line 22 are opposite but the disconnection rate is too large, then the current of the secondary gate that cannot be intercepted at the disconnection point of the boundary grid line is large, which will lead to high leakage, and the potential difference cannot be made as low as possible. The area on both sides of the non-electrode area 13 can only be made to work independently through slicing. If the disconnection rate of the first boundary grid line 21 and the second boundary grid line 22 is less than or equal to 5%, but the polarity of the first boundary grid line 21 and the second boundary grid line 22 is not opposite, the carriers of one boundary grid line will pass through the non-electrode area 13 directly from the surface of the silicon wafer 10 to the other boundary grid line, and will not pass through the PN junction inside the silicon wafer 10, thereby causing serious leakage. The area on both sides of the non-electrode area 13 can only be made to work independently through slicing.

[0033] In the present application, the first boundary grid line 21 and the second boundary grid line 22 have opposite polarities and a disconnection rate of less than or equal to 5%. Therefore, the disconnected portion of the boundary grid line can intercept most or even all of the current in the secondary gate. In addition, the carriers of one boundary grid line do not need to travel directly from the surface of the silicon wafer 10 through the non-electrode region 13 to the other boundary grid line, but instead pass through the PN junction inside the silicon wafer 10. This can reduce the risk of leakage, making the potential difference as low as possible or even close to zero, and eliminating the need for slicing to make the areas on both sides of the non-electrode region 13 operate independently.

[0034] Optionally, the silicon wafer 10 includes a light-facing surface and a backlight surface facing each other, the backlight surface forms a first electrode area 11, a second electrode area 12 and a non-electrode area 13, the first electrode area 11 and the second electrode area 12 are both provided with electrode structures, and the non-electrode area 13 is not provided with an electrode structure.

[0035] Optionally, the number of first electrode areas 11 may be 1, 2, 3 or another number. The sizes of the multiple first electrode areas 11 may be the same or different. The electrode structures of the multiple first electrode areas 11 may be the same or different. The number of second electrode areas 12 may be 1, 2, 3 or another number. The sizes of the multiple second electrode areas 12 may be the same or different. The electrode structures of the multiple second electrode areas 12 may be the same or different. The number of non-electrode areas 13 may be 1, 2, 3 or another number. The sizes of the multiple non-electrode areas 13 may be the same or different. The number, quantity relationship, size relationship, etc. of the first electrode areas 11, the second electrode areas 12 and the non-electrode areas 13 are not limited here.

[0036] Optionally, the non-electrode region 13 is located between the first electrode region 11 and the second electrode region 12 . That is, the first electrode region 11 and the second electrode region 12 are respectively located on both sides of the non-electrode region 13 and are separated by the non-electrode region 13 .

[0037] Optionally, the first boundary gate line 21 is the gate line of the electrode structure located in the first electrode area 11 closest to the non-electrode area 13. In other words, the first boundary gate line 21 is the boundary line of the first electrode area 11 and the boundary line between the first electrode area 11 and the non-electrode area 13.

[0038] Optionally, the first boundary grid line 21 may be a secondary grid, as shown in Figures 1, 2, 3 and 4. The first boundary grid line 21 may be a main grid, as shown in Figures 5 and 6.

[0039] Optionally, the first boundary grid lines 21 may be straight lines, broken lines, curves, arcs, or lines of other shapes. This embodiment uses the straight line as an example for description, but this does not limit the specific shape of the first boundary grid lines 21 .

[0040] Alternatively, when the first boundary grid lines 21 are straight lines, the length direction of the first boundary grid lines 21 may be parallel to the length direction of the secondary grid, as shown in Figures 1, 2, 3, and 4. The length direction of the first boundary grid lines 21 may be perpendicular to the length direction of the secondary grid, as shown in Figures 5 and 6. It will be understood that in other examples, the length direction of the first boundary grid lines 21 may form an acute angle or an obtuse angle with the length direction of the secondary grid. The specific length direction of the first boundary grid lines 21 is not limited herein.

[0041] Optionally, the second boundary gate line 22 is the gate line of the electrode structure in the second electrode area 12 closest to the non-electrode area 13. In other words, the second boundary gate line 22 is the boundary line of the second electrode area 12 and the boundary line between the second electrode area 12 and the non-electrode area 13.

[0042] Optionally, the first boundary grid lines 21 and the second boundary grid lines 22 are parallel to each other. In this way, the shape of the non-electrode area 13 is more regular, which facilitates the production of the electrode areas on both sides and helps improve production efficiency. It is understood that the first boundary grid lines 21 and the second boundary grid lines 22 may not be parallel to each other, that is, the length directions of the first boundary grid lines 21 and the second boundary grid lines 22 may also intersect.

[0043] Please note that the second boundary grid line 22 is similar to the first boundary grid line 21 . For the explanation and description of the second boundary grid line 22 , reference may be made to the above explanation and description of the first boundary grid line 21 . To avoid redundancy, details will not be repeated here.

[0044] It can be understood that the area between the first boundary gate line 21 and the second boundary gate line 22 is the non-electrode area 13 .

[0045] Optionally, the polarities of the first boundary grid line 21 and the second boundary grid line 22 are opposite, which may mean that the polarity of the first boundary grid line 21 is negative and the polarity of the second boundary grid line 22 is positive; or it may mean that the polarity of the first boundary grid line 21 is positive and the polarity of the second boundary grid line 22 is negative.

[0046] Optionally, the disconnection point of the first boundary grid line 21 may be located at the middle portion and / or end portion of the first boundary grid line 21. The disconnection point of the second boundary grid line 22 may be located at the middle portion and / or end portion of the second boundary grid line 22. The disconnection point of the first boundary grid line 21 and the disconnection point of the second boundary grid line 22 may be completely aligned, partially overlapped, or completely staggered.

[0047] Optionally, the disconnection rate refers to the ratio of the length of the disconnected portion of the boundary grid line to the total length of the boundary grid line. In other words, the disconnection rate of the first boundary grid line 21 refers to the ratio of the length of the disconnected portion of the first boundary grid line 21 to the total length of the first boundary grid line 21. The disconnection rate of the second boundary grid line 22 refers to the ratio of the length of the disconnected portion of the second boundary grid line 22 to the total length of the second boundary grid line 22.

[0048] Optionally, the disconnection rate of the first boundary grid line 21 is, for example, 5%, 4.8%, 4%, 2%, 1%, 0.1%, or 0%.

[0049] Optionally, the disconnection rate of the second boundary grid line 22 is, for example, 5%, 4.8%, 4%, 2%, 1%, 0.1%, or 0%.

[0050] Optionally, the disconnection rate of the first boundary grid line 21 and the disconnection rate of the second boundary grid line 22 may be the same or different.

[0051] Referring to Figures 1, 2, 5, 6, and 9, the back-contact cell 100 may further include a solder pad 40 and an electrical connector 200. The electrical connector 200 is used to connect the solder pads 40 of two adjacent back-contact cells 100. This facilitates the connection of two adjacent back-contact cells 100, improving the efficiency of battery string production. Furthermore, the electrical connector 200 may be a conductive wire, solder ribbon, or the like. The specific form of the electrical connector 200 is not limited herein.

[0052] Example 2

[0053] Referring to Figures 1, 2, 3, 4, 5 and 6, in some embodiments, the disconnection rate of the first boundary grid line 21 and the second boundary grid line 22 are both 0%, and the first boundary grid line 21 and the second boundary grid line 22 are continuously arranged on both sides of the non-electrode area 13.

[0054] In this way, the potential difference of the non-electrode area 13 is made as close to 0 as possible, so that the areas on both sides of the non-electrode area 13 can work independently in the state of sliced ​​batteries without physically cutting the non-electrode area 13, achieving the same effect as if the non-electrode area 13 was physically cut, making the work of the areas on both sides of the non-electrode area 13 as independent as possible.

[0055] It can be understood that the disconnection rate of the first boundary grid lines 21 is 0%, that is, the first boundary grid lines 21 are continuously arranged without disconnected parts. The disconnection rate of the second boundary grid lines 22 is 0%, that is, the second boundary grid lines 22 are continuously arranged without disconnected parts.

[0056] It is understandable that if the polarity of the first boundary grid line 21 and the second boundary grid line 22 are opposite but discontinuous, then the disconnection of the boundary grid line cannot intercept the current of the secondary gate, which will cause leakage, and the potential difference cannot be close to 0. The area on both sides of the non-electrode area 13 can only be operated independently through slicing. If the disconnection rate of the first boundary grid line 21 and the second boundary grid line 22 is 0%, but the polarity of the first boundary grid line 21 and the second boundary grid line 22 is not opposite, the carriers of one boundary grid line will pass through the non-electrode area 13 directly from the surface of the silicon wafer 10 to the other boundary grid line, without passing through the PN junction inside the silicon wafer 10, thereby causing serious leakage. The area on both sides of the non-electrode area 13 can only be operated independently through slicing.

[0057] Example 3

[0058] 1 , 2 , 3 , 4 , 5 and 6 , in some embodiments, the width d of the non-electrode region 13 is 0.05 mm-1.0 mm, for example, 0.05 mm, 0.06 mm, 0.1 mm, 0.5 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0059] In this way, the width d of the non-electrode area 13 is within an appropriate range, which can avoid the serious reduction in the effect of the two boundary gate lines intercepting current due to the small width d of the non-electrode area 13, and can also avoid the waste of power generation area due to the excessive width d of the non-electrode area 13.

[0060] Preferably, the width d of the non-electrode region 13 is 0.6 mm to 0.8 mm. For example, it is 0.6 mm, 0.62 mm, 0.65 mm, 0.67 mm, 0.7 mm, 0.75 mm, 0.78 mm, or 0.8 mm. By further optimizing the width d of the non-electrode region 13, both the boundary grid line's current interception effect and the full utilization of the power generation area are taken into account, resulting in a better overall effect.

[0061] Example 4

[0062] In some embodiments, the width of the first boundary grid line 21 is 10 μm-1.5 mm, for example, 10 μm, 12 μm, 50 μm, 100 μm, 300 μm, 500 μm, 800 μm, 1 mm, 1.2 mm, or 1.5 mm.

[0063] In this way, the width of the first boundary gate line 21 is within an appropriate range, which can avoid the process difficulty or even impossibility caused by too small a width, as well as the gate breakage caused by too small a width, and can also avoid material waste and high costs caused by too large a width.

[0064] Preferably, the width of the first boundary grid lines 21 is 800 μm-1000 μm, for example, 800 μm, 810 μm, 850 μm, 880 μm, 900 μm, 980 μm, or 1000 μm. This further optimizes the width of the first boundary grid lines 21 while taking into account process difficulty, grid line quality, and cost, resulting in a better overall effect.

[0065] Example 5

[0066] In some embodiments, the thickness of the first boundary grid line 21 is 1 μm-20 μm, for example, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, or 20 μm.

[0067] In this way, the thickness of the first boundary grid line 21 is within an appropriate range, which can avoid the process difficulty or even impossibility caused by too small a thickness, and can also avoid the material waste and high cost caused by too large a thickness.

[0068] Preferably, the thickness of the first boundary grid lines 21 is 9 μm-11 μm, for example, 9 μm, 9.2 μm, 9.5 μm, 10 μm, 10.3 μm, 10.5 μm, 10.8 μm, or 11 μm. In this way, the thickness of the first boundary grid lines 21 is further optimized, taking into account both process difficulty and cost, resulting in a better overall effect.

[0069] Example 6

[0070] In some embodiments, the width of the second boundary grid line 22 is 10 μm-1.5 mm, for example, 10 μm, 12 μm, 50 μm, 100 μm, 300 μm, 500 μm, 800 μm, 1 mm, 1.2 mm, or 1.5 mm.

[0071] In this way, the width of the second boundary gate line 22 is within an appropriate range, which can avoid the process difficulty or even impossibility caused by too small a width, as well as the gate breakage caused by too small a width, and can also avoid material waste and high costs caused by too large a width.

[0072] Preferably, the width of the second boundary grid lines 22 is 800 μm-1000 μm, for example, 800 μm, 810 μm, 850 μm, 880 μm, 900 μm, 980 μm, or 1000 μm. This further optimizes the width of the second boundary grid lines 22 while taking into account process difficulty, grid line quality, and cost, resulting in a better overall effect.

[0073] Example 7

[0074] In some embodiments, the thickness of the second boundary grid line 22 is 1 μm-20 μm, for example, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, or 20 μm.

[0075] In this way, the thickness of the second boundary grid line 22 is within an appropriate range, which can avoid the process difficulty or even impossibility caused by too small a thickness, and can also avoid the material waste and high cost caused by too large a thickness.

[0076] Preferably, the thickness of the second boundary grid lines 22 is 9 μm-11 μm, for example, 9 μm, 9.2 μm, 9.5 μm, 10 μm, 10.3 μm, 10.5 μm, 10.8 μm, or 11 μm. In this way, the thickness of the second boundary grid lines 22 is further optimized, taking into account both process difficulty and cost, resulting in a better overall effect.

[0077] Example 8

[0078] In some embodiments, the deviation distance between the ends of the first boundary grid line 21 and the second boundary grid line 22 is less than or equal to 3 mm, for example, 3 mm, 2.8 mm, 2.5 mm, 2 mm, 1.5 mm, 1 mm, or 0.1 mm.

[0079] In this way, the deviation distance between the ends of the first boundary grid line 21 and the second boundary grid line 22 is within an appropriate range, which can avoid the current of the auxiliary gate that cannot be intercepted due to excessive deviation, resulting in more leakage, and the inability to make the potential difference as low as possible. The area on both sides of the non-electrode area 13 can only work independently through slicing.

[0080] Optionally, the deviation distance refers to the distance that one boundary grid line extends beyond another boundary grid line in its width direction. That is, the distance that the first boundary grid line 21 extends beyond the second boundary grid line 22 in the width direction of the first boundary grid line 21; and the distance that the second boundary grid line 22 extends beyond the first boundary grid line 21 in the width direction of the second boundary grid line 22.

[0081] Embodiment 9

[0082] In some embodiments, the deviation distance between the ends of the first boundary grid line 21 and the second boundary grid line 22 is 0 mm, and the ends of the first boundary grid line 21 and the second boundary grid line 22 are completely aligned.

[0083] In this way, the ends of the first boundary grid line 21 and the second boundary grid line 22 are completely aligned in the width direction, the first boundary grid line 21 will not exceed the second boundary grid line 22, and the second boundary grid line 22 will not exceed the first boundary grid line 21, so that the current of the auxiliary gate can be intercepted as much as possible, the risk of leakage is reduced, and the potential difference is made as low as possible, so that the areas on both sides of the non-electrode area 13 can work independently without slicing.

[0084] Example 10

[0085] Referring to FIG. 1 , FIG. 2 , FIG. 3 , and FIG. 4 , in some embodiments, the first boundary gate line 21 and the second boundary gate line 22 extend along a first direction of the silicon wafer 10 , and the first electrode region 11 and the second electrode region 12 are spaced apart along a second direction of the silicon wafer 10 , where the second direction intersects the first direction.

[0086] The first boundary gate line 21 is a secondary gate located at the end of the electrode structure of the first electrode region 11 close to the non-electrode region 13 ; the second boundary gate line 22 is a secondary gate located at the end of the electrode structure of the second electrode region 12 close to the non-electrode region 13 .

[0087] In this way, the first boundary grid line 21 and the second boundary grid line 22 are both auxiliary grids, the arrangement direction of the first electrode area 11 and the second electrode area 12 intersects with the length direction of the auxiliary grid, the positions of the boundary grid lines and the electrode areas are coordinated, and the arrangement is relatively regular, which is conducive to improving production efficiency.

[0088] Optionally, the first direction is a length direction of the auxiliary grid, and the second direction is a direction crossing the length direction of the auxiliary grid.

[0089] In this embodiment, the second direction is perpendicular to the length direction of the secondary gate. This allows for a more regular arrangement of the boundary gate lines and the electrode regions, making full use of the space of the silicon wafer 10. It will be appreciated that in other embodiments, the second direction may also form an acute or obtuse angle with the length direction of the secondary gate.

[0090] Example 11

[0091] Please refer to Figures 3 and 4. In some embodiments, the back-contact cell 100 is a busbar-less cell, and the electrode structure includes a plurality of first sub-grids 231 and a plurality of second sub-grids 232. The plurality of first sub-grids 231 and the plurality of second sub-grids 232 are alternately arranged in sequence and spaced apart along the second direction of the silicon wafer 10.

[0092] In this way, the back contact cell 100 does not require a busbar, which can reduce the consumption of electrode slurry and help reduce costs.

[0093] Optionally, the first sub-grid 231 and the second sub-grid 232 have different polarities. In other words, when the polarity of the first sub-grid 231 is positive, the polarity of the second sub-grid 232 is negative; when the polarity of the first sub-grid 231 is negative, the polarity of the second sub-grid 232 is positive.

[0094] Optionally, the number of the first sub-grids 231 may be 1, 2, 3 or other numbers. The number of the second sub-grids 232 may be 1, 2, 3 or other numbers. The number of the first sub-grids 231 and the second sub-grids 232 may be the same or different.

[0095] Optionally, the plurality of first sub-gates 231 and the plurality of second sub-gates 232 are alternately arranged in sequence along the second direction of the silicon wafer 10 , which means that a second sub-gate 232 is provided between two adjacent first sub-gates 231 , and a first sub-gate 231 is provided between two adjacent second sub-gates 232 .

[0096] Optionally, the plurality of first sub-gates 231 and the plurality of second sub-gates 232 are sequentially spaced apart along the second direction of the silicon wafer 10 , which means that gaps are formed between adjacent first sub-gates 231 and second sub-gates 232 .

[0097] Example 12

[0098] Referring to FIG. 1 and FIG. 2 , in some embodiments, the electrode structure includes:

[0099] A plurality of first auxiliary gates 231 and a plurality of second auxiliary gates 232 , wherein the plurality of first auxiliary gates 231 and the plurality of second auxiliary gates 232 are alternately arranged in sequence and spaced apart along the second direction of the silicon wafer 10 ; and

[0100] Several first main grids 241 and several second main grids 242 are arranged alternately and spaced apart in sequence along the first direction. Each first main grid 241 is connected to all first sub-grids 231 in the electrode structure, and each second main grid 242 is connected to all second sub-grids 232 in the electrode structure.

[0101] In this way, the back-contact cell 100 has a busbar, which can collect current from the secondary grid and converge it to the outside of the cell through a conductive member 30 such as a soldering ribbon, thereby improving the current extraction effect. In addition, the busbar lines are generally wider, which facilitates connection with the conductive member 30 such as the soldering ribbon, thereby improving manufacturing efficiency.

[0102] The explanation and description of the first sub-gate 231 and the second sub-gate 232 can be referred to above, and will not be repeated here to avoid redundancy.

[0103] Optionally, the first busbar 241 and the second busbar 242 have different polarities. In other words, when the first busbar 241 is positive, the second busbar 242 is negative; and when the first busbar 241 is negative, the second busbar 242 is positive.

[0104] Optionally, the number of first bus bars 241 may be 1, 2, 3, or other numbers. The number of second bus bars 242 may be 1, 2, 3, or other numbers. The number of first bus bars 241 and second bus bars 242 may be the same or different.

[0105] Optionally, several first main gates 241 and several second main gates 242 are alternately arranged in sequence along the first direction of the silicon wafer 10 , which means that a second main gate 242 is provided between two adjacent first main gates 241 , and a first main gate 241 is provided between two adjacent second main gates 242 .

[0106] Optionally, a plurality of first main gates 241 and a plurality of second main gates 242 are sequentially spaced apart along the second direction of the silicon wafer 10 , which means that gaps are formed between adjacent first main gates 241 and second main gates 242 .

[0107] Example 13

[0108] 1 and 2 , in some embodiments, the first busbar 241 of the electrode structure located in the first electrode region 11 and the second busbar 242 of the electrode structure located in the second electrode region 12 are aligned in the second direction;

[0109] The second bus gate 242 of the electrode structure located in the first electrode region 11 and the first bus gate 241 of the electrode structure located in the second electrode region 12 are aligned in the second direction.

[0110] In this way, in the electrode structure of the first electrode region 11 and the second electrode region 12, the opposite-type busbars are aligned in the length direction of the busbars, which facilitates the subsequent connection of the opposite-type busbars of the two electrode regions with welding ribbons, thereby improving the manufacturing efficiency of the battery string.

[0111] Optionally, the first busbar 241 of the electrode structure located in the first electrode region 11 and the second busbar 242 of the electrode structure located in the second electrode region 12 are aligned in the second direction, which means that the projections of the first busbar 241 of the electrode structure located in the first electrode region 11 and the second busbar 242 of the electrode structure located in the second electrode region 12 on the same plane along the second direction have an overlapping portion. Similarly, the second busbar 242 of the electrode structure located in the first electrode region 11 and the first busbar 241 of the electrode structure located in the second electrode region 12 are aligned in the second direction, which means that the projections of the second busbar 242 of the electrode structure located in the first electrode region 11 and the first busbar 241 of the electrode structure located in the second electrode region 12 on the same plane along the second direction have an overlapping portion.

[0112] Furthermore, the center lines of the first busbar 241 of the electrode structure located in the first electrode region 11 and the second busbar 242 of the electrode structure located in the second electrode region 12 are located on the same straight line. Similarly, the center lines of the second busbar 242 of the electrode structure located in the first electrode region 11 and the first busbar 241 of the electrode structure located in the second electrode region 12 are located on the same straight line. This allows the center lines of the opposite-sex busbars in the electrode structures of the two electrode regions to be located on the same straight line, which improves alignment and further facilitates subsequent welding.

[0113] Furthermore, the first busbar 241 of the electrode structure located in the first electrode region 11 and the second busbar 242 of the electrode structure located in the second electrode region 12 have the same width. In other words, the projections of the first busbar 241 of the electrode structure located in the first electrode region 11 and the second busbar 242 of the electrode structure located in the second electrode region 12 on the same plane along the second direction completely overlap. This ensures that the opposite-sex busbars in the electrode structures of the two electrode regions are fully aligned in the second direction, maximizing alignment accuracy and facilitating subsequent welding.

[0114] Example 14

[0115] Please refer to Figures 5 and 6. In some embodiments, the first electrode region 11 and the second electrode region 12 are spaced apart along a first direction of the silicon wafer 10, and the first boundary gate line 21 and the second boundary gate line 22 extend along a second direction of the silicon wafer 10, and the second direction intersects with the first direction. The first boundary gate line 21 is the main gate located at the end of the electrode structure of the first electrode region 11 close to the non-electrode region 13; the second boundary gate line 22 is the main gate located at the end of the electrode structure of the second electrode region 12 close to the non-electrode region 13.

[0116] In this way, the first boundary grid line 21 and the second boundary grid line 22 are both main grids, the arrangement direction of the first electrode area 11 and the second electrode area 12 intersects with the length direction of the main grid, the positions of the boundary grid lines and the electrode areas are coordinated, and the arrangement is relatively regular, which is conducive to improving production efficiency.

[0117] Optionally, the second direction is a length direction of the main grid, and the first direction is a direction crossing the length direction of the main grid.

[0118] In this embodiment, the first direction is perpendicular to the length direction of the main gate. This allows for a more regular arrangement of the boundary gate lines and the electrode regions, making full use of the space on the silicon wafer 10. It will be appreciated that in other embodiments, the first direction may also form an acute or obtuse angle with the length direction of the main gate.

[0119] Please refer to Figures 7 and 8 together. The back-contact cell 100 may further include a conductive member 30, which is used to electrically connect the adjacent first boundary grid lines 21 and second boundary grid lines 22. In this way, the opposite-sex busbars located on both sides of the non-electrode area 13 can be efficiently connected, realizing the connection of the electrode structures that work independently in the two electrode areas.

[0120] Furthermore, the conductive member 30 can be formed by solidifying a conductive material, as shown in Figure 7. The conductive material is, for example, solder paste, conductive glue, etc. Furthermore, there are multiple conductive members 30, and the spacing between two adjacent conductive members 30 is less than or equal to 30 mm. For example, it is 30 mm, 28 mm, 25 mm, 20 mm, 18 mm, 10 mm, 5 mm, or 1 mm. In this way, the spacing between two adjacent conductive members 30 is within a suitable range, which can avoid the poor electrical conductivity of the heterogeneous boundary main grid caused by excessive spacing. Furthermore, the width of the conductive member 30 is 0.5 mm-2 mm. For example, it is 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm. The width of the conductive member 30 refers to the size of the conductive member 30 in the length direction of the boundary grid line. In this way, the width of the conductive member 30 is within a suitable range, which can avoid easy breakage or difficulty in achieving the process due to too small a width, and can also avoid wasting materials and increasing costs due to too large a width.

[0121] Furthermore, the conductive member 30 may include a solder strip, as shown in FIG8 . The length direction of the solder strip is parallel to the length direction of the boundary grid line. In this way, the heterogeneous main grids located on both sides of the non-electrode area 13 can be efficiently connected, which is beneficial to improving the production efficiency of the battery string.

[0122] Referring also to Figure 9 , the back-contact cell 100 may also include a solder pad 40 and an electrical connector 200. The electrical connector 200 is used to connect the solder pads 40 of two adjacent back-contact cells 100. This facilitates the connection of two adjacent back-contact cells 100, improving the efficiency of battery string production. Furthermore, the electrical connector 200 may be a conductive wire, solder ribbon, or the like. The specific form of the electrical connector 200 is not limited herein.

[0123] Example 15

[0124] Referring to FIG. 5 and FIG. 6 , in some embodiments, the electrode structure includes:

[0125] A plurality of first auxiliary gates 231 and a plurality of second auxiliary gates 232 , wherein the plurality of first auxiliary gates 231 and the plurality of second auxiliary gates 232 are alternately arranged in sequence and spaced apart along the second direction of the silicon wafer 10 ; and

[0126] A first main gate 241 and a second main gate 242 are arranged at intervals along a first direction. The first main gate 241 is located on one side of the first and second auxiliary gates 231 and 232 and is connected to the ends of all the first auxiliary gates 231. The second main gate 242 is located on the other side of the first and second auxiliary gates 231 and 232 and is connected to the ends of all the second auxiliary gates 232.

[0127] A non-electrode region 13 is formed between the adjacent first main gate 241 and the second main gate 242 .

[0128] In this way, using the opposite-sex busbars as boundary lines and forming a non-electrode region 13 between the opposite-sex busbars can avoid gate breakage caused by too small a width of the boundary lines, thereby ensuring that the boundary lines effectively intercept current. Furthermore, when connecting the electrode structure of the first electrode region 11 and the second electrode region 12, the conductive member 30 only needs to be placed between the opposite-sex boundary lines on both sides of the non-electrode region 13, which is relatively simple and convenient.

[0129] For explanations and descriptions of the first auxiliary gate 231 , the second auxiliary gate 232 , the first main gate 241 and the second main gate 242 , please refer to the above text, and will not be repeated here to avoid redundancy.

[0130] Example 16

[0131] The battery assembly of the embodiment of the present application includes the back-contact battery cell 100 of any one of the first to fifteenth embodiments.

[0132] In the battery assembly of the embodiment of the present application, since the boundary grid lines of the two electrode structures in the back contact cell 100 have opposite polarities and the disconnection rate is less than or equal to 5%, the potential difference of the non-electrode region 13 can be kept as low as possible. As a result, without physically cutting the non-electrode region 13, the areas on both sides of the non-electrode region 13 can operate independently in a state close to that of a sliced ​​cell, achieving an effect similar to that of physically cutting the non-electrode region 13. In this way, while achieving an effect similar to that of slicing, the slicing step and slicing equipment can be omitted, reducing costs.

[0133] In this embodiment, multiple back-contact battery cells 100 in the battery assembly can be connected in series in sequence to form a battery string, thereby realizing the series bus output of the current. For example, the series connection of the battery cells can be realized by setting welding strips (bus bars, interconnecting bars), conductive back plates, etc.

[0134] It is understood that in such an embodiment, the battery assembly may further include a metal frame, a backsheet, photovoltaic glass, and an adhesive film. The adhesive film may be filled between the front and back surfaces of the back contact cell 100, the photovoltaic glass, adjacent cells, etc., and may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be EVA film or POE film. The specific choice may be based on actual conditions and is not limited here.

[0135] Photovoltaic glass can cover the adhesive film on the front side of the back-contact cell 100. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, ultra-clear glass can have a light transmittance of over 92%, protecting the back-contact cell 100 while minimizing its efficiency. The adhesive film can also bond the photovoltaic glass and back-contact cell 100 together, providing sealing, insulation, and waterproofing for the back-contact cell 100.

[0136] The backsheet can be attached to the film on the back of the back-contact cell 100. It provides protection and support for the back-contact cell 100 and offers reliable insulation, water resistance, and aging resistance. A variety of backsheet options are available, typically including tempered glass, organic glass, and aluminum alloy TPT composite film. The specific configuration depends on the specific situation and is not limited here. The backsheet, back-contact cell 100, film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the primary external support structure for the entire battery assembly and provides stable support and installation for the battery assembly. For example, the metal frame can be used to mount the battery assembly in the desired location.

[0137] Embodiment 17

[0138] The photovoltaic system of the embodiment of the present application includes the battery assembly of the sixteenth embodiment.

[0139] In the photovoltaic system of the embodiment of the present application, since the boundary grid lines of the two electrode structures in the back-contact cell 100 have opposite polarities and a disconnection rate of less than or equal to 5%, the potential difference in the non-electrode region 13 can be kept as low as possible. As a result, without physically cutting the non-electrode region 13, the areas on both sides of the non-electrode region 13 can operate independently in a state close to that of a sliced ​​cell, achieving an effect similar to that of physically cutting the non-electrode region 13. In this way, while achieving an effect similar to that of slicing, the slicing step and slicing equipment can be omitted, reducing costs.

[0140] In this embodiment, the photovoltaic system can be applied to photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple battery modules. For example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter to be converted into the alternating current required by the mains power grid and then connected to the mains power network to achieve solar power supply.

[0141] Throughout this specification, reference to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0142] In addition, the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A back-contact solar cell, characterized in that, It includes a silicon wafer and several electrode structures. On the backlight side of the silicon wafer, a first electrode region, a second electrode region, and a non-electrode region are formed. The non-electrode region is located between the first electrode region and the second electrode region. The electrode structure in the first electrode region includes a first boundary gate line, and the electrode structure in the second electrode region includes a second boundary gate line. The polarities of the first boundary gate line and the second boundary gate line are opposite, and the disconnection rates of the first boundary gate line and the second boundary gate line are both less than or equal to 5%.

2. The back-contact solar cell according to claim 1, characterized in that, The disconnection rates of the first boundary gate line and the second boundary gate line are both 0%, and the first boundary gate line and the second boundary gate line are continuously arranged on both sides of the non-electrode region respectively.

3. The back-contact solar cell according to claim 1, wherein, The width of the non-electrode region is 0.05 mm - 1.0 mm.

4. The back contact cell according to claim 1, wherein The width of the first boundary gate line is 10 μm - 1.5 mm.

5. The back-contact cell according to claim 1, wherein, The thickness of the first boundary gate line is 1 μm - 20 μm.

6. The back contact cell according to claim 1, wherein, The width of the second boundary gate line is 10 μm - 1.5 mm.

7. The back-contact cell according to claim 1, characterized in that, The thickness of the second boundary gate line is 1 μm - 20 μm.

8. The back-contact cell according to claim 1, characterized in that, The deviation distance between the ends of the first boundary gate line and the second boundary gate line is less than or equal to 3 mm.

9. The back-contact solar cell according to claim 8, wherein, The deviation distance between the ends of the first boundary gate line and the second boundary gate line is 0 mm, and the ends of the first boundary gate line and the second boundary gate line are completely aligned.

10. The back-contact cell according to claim 1, characterized in that, The first boundary gate line and the second boundary gate line extend along the first direction of the silicon wafer. The first electrode region and the second electrode region are arranged at intervals along the second direction of the silicon wafer, and the second direction intersects with the first direction; The first boundary gate line is a sub-gate at the end of the electrode structure in the first electrode region close to the non-electrode region; The second boundary gate line is a sub-gate at the end of the electrode structure in the second electrode region close to the non-electrode region.

11. The back contact cell according to claim 10, wherein, The back-contact cell is a cell without a main gate. The electrode structure includes several first sub-gates and several second sub-gates. The several first sub-gates and the several second sub-gates are alternately arranged in sequence and at intervals along the second direction of the silicon wafer.

12. The back-contact solar cell according to claim 10, characterized in that, The electrode structure includes: Several first sub-gates and several second sub-gates, and the several first sub-gates and the several second sub-gates are alternately arranged in sequence and at intervals along the second direction of the silicon wafer; and Several first main gates and several second main gates, and the several first main gates and the several second main gates are alternately arranged in sequence and at intervals along the first direction. Each first main gate is connected to all the first sub-gates in the electrode structure, and each second main gate is connected to all the second sub-gates in the electrode structure.

13. The back contact cell according to claim 12, wherein, The first main gate of the electrode structure in the first electrode region is aligned with the second main gate of the electrode structure in the second electrode region in the second direction; The second main gate of the electrode structure in the first electrode region is aligned with the first main gate of the electrode structure in the second electrode region in the second direction.

14. The back contact solar cell according to claim 1, characterized in that, The first electrode region and the second electrode region are arranged at intervals along a first direction of the silicon wafer. The first boundary gate line and the second boundary gate line extend along a second direction of the silicon wafer. The second direction intersects the first direction. The first boundary gate line is a main gate located at an end of the electrode structure in the first electrode region close to the non-electrode region. The second boundary gate line is a main gate located at an end of the electrode structure in the second electrode region close to the non-electrode region.

15. The back contact cell according to claim 14, wherein, The electrode structure includes: a plurality of first sub-gates and a plurality of second sub-gates, the plurality of first sub-gates and the plurality of second sub-gates are alternately arranged in sequence and at intervals along the second direction of the silicon wafer; and a first main gate and a second main gate, the first main gate and the second main gate are arranged at intervals along the first direction. The first main gate is located on one side of the first sub-gates and the second sub-gates and is connected to ends of all the first sub-gates. The second main gate is located on the other side of the first sub-gates and the second sub-gates and is connected to ends of all the second sub-gates; wherein, a non-electrode region is formed between the adjacent first main gate and the second main gate.

16. A battery assembly, characterized in that, A back-contact solar cell piece according to any one of claims 1-15.

17. A photovoltaic system, characterized in that, A battery assembly according to claim 16.

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