Heterojunction cell and method for edge passivation thereof, and laminated cell module
Patent Information
- Application Number
- CN202610798558.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-03
- Publication Date
- 2026-10-16
AI Technical Summary
目前通常会将异质结电池片切割成三分片、四分片或者多分片后，再进行叠层焊接封装，而低温电池片切割后切割边缘效率损失较大，传统的钝化结构是在切割边缘采用i层（本征非晶硅层）钝化，可靠性较差
[0032] The passivation structure deposited at the cut surface of the silicon substrate includes a first intrinsic amorphous silicon layer and a silicon nitride layer, with the first intrinsic amorphous silicon layer located between the silicon nitride layer and the silicon substrate. This passivation structure has good passivation effect, is resistant to moisture and acid corrosion, and has high reliability. In addition, passivation structures are deposited around the edges of the front and back sides of the silicon substrate near the cut surface to reduce the conduction leakage problem between adjacent cells after negative spacing stacking of the cells.
Smart Images
Figure CN122934977A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell technology, and in particular to a heterojunction solar cell and its edge passivation method, and a stacked solar cell module. Background Technology
[0002] Heterojunction solar cells, also known as HJT solar cells, are a common type of low-temperature solar cell. Currently, heterojunction solar cells are usually cut into three, four, or more pieces before being stacked and welded together for encapsulation. However, the efficiency loss at the cutting edges of low-temperature solar cells is significant after cutting. Traditional passivation structures use an i-layer (intrinsic amorphous silicon layer) for passivation at the cutting edges, which results in poor reliability. Summary of the Invention
[0003] Therefore, it is necessary to provide a heterojunction solar cell and its edge passivation method, as well as a tandem solar cell module, to enhance the reliability of the passivation structure at the cut edge of the heterojunction solar cell, and the tandem solar cell module using the heterojunction solar cell can reduce the problem of large leakage current.
[0004] This application provides a heterojunction solar cell, wherein the heterojunction solar cell has two outer surfaces that are opposite to each other along its thickness direction, namely a front surface and a back surface. The front surface and the back surface are connected by a side surface. The side surface includes a cut surface, and the cut surface is provided with a passivation structure and the passivation structure extends to the front surface and the back surface, so that the passivation structure is provided at the edge position of the front surface near the cut surface and the edge position of the back surface near the cut surface. The passivation structure includes a first intrinsic amorphous silicon layer and a silicon nitride layer stacked together. The heterojunction solar cell includes a silicon substrate, and the first intrinsic amorphous silicon layer is located between the silicon nitride layer and the silicon substrate.
[0005] In one embodiment, a portion of the edge position on the back side near the cut surface is defined as an edge region, the edge region being in contact with the cut surface, and the edge region not having a TCO film deposited.
[0006] In one embodiment, the width of the edge region is 0.5mm-2mm along the direction perpendicular to the cut surface.
[0007] In one embodiment, the width of the passivation structure on the front side is 0.1mm-5mm along the direction perpendicular to the cut surface, and the width of the passivation structure on the back side is 0.1mm-5mm.
[0008] In one embodiment, a TCO film is deposited on both the side of the silicon substrate facing the front side and the side facing the back side, and a passivation structure disposed on the front side at least partially covers the TCO film on the front side, and a passivation structure disposed on the back side at least partially covers the TCO film on the back side.
[0009] This application also provides an edge passivation method for heterojunction solar cells, used to passivate the edges of the cut surfaces of the aforementioned heterojunction solar cells. The edge passivation method includes the following steps:
[0010] Multiple cut heterojunction solar cells are stacked along the thickness direction of the heterojunction solar cells to form a stack. The cut surfaces of each heterojunction solar cell face the same direction. The thickness direction of the stack is consistent with the thickness direction of the heterojunction solar cells. There are gaps between adjacent heterojunction solar cells.
[0011] The stack is placed in the fixture, and the fixture clamps the stack along the thickness direction of the stack.
[0012] A hot-wire CVD device is used to deposit passivation structures on the cut surfaces of heterojunction solar cells in a stack. During the deposition process, the passivation structures are penetrated into the gaps between the heterojunction solar cells to deposit passivation structures around the edges of the front and back sides of the heterojunction solar cells near the cut surfaces.
[0013] In one embodiment, before depositing the passivation structure, the gap between the heterojunction solar cells is adjusted by adjusting the clamping pressure of the clamp on the heterojunction solar cells.
[0014] In one embodiment, the clamping pressure of the clamp on the heterojunction solar cell and the gap between adjacent heterojunction solar cells satisfy the following:
[0015] D = F × (d1 + d2 + d3) × M × X;
[0016] S = [(d1 + d2 + d3) × MD] / (M - 1);
[0017] D is the total thickness of the stacked heterojunction solar cells;
[0018] F represents the clamping pressure of the fixture on the heterojunction solar cell;
[0019] d1 represents the thickness of a single heterojunction solar cell after the TCO film is deposited using the PVD process.
[0020] d2 is the grid line height on the front side of the finished heterojunction solar cell;
[0021] d3 is the grid line height on the back of the finished heterojunction solar cell;
[0022] M represents the number of heterojunction solar cells;
[0023] X is the correction factor;
[0024] S is the gap between adjacent heterojunction solar cells;
[0025] The passivation structure wrap-around widths on both the front and back sides of the heterojunction solar cell meet the following requirements:
[0026] L = x1 × S;
[0027] L represents the width of the passivation structure on the front or back of the heterojunction solar cell.
[0028] x1 is the fitting coefficient.
[0029] In one embodiment, TCO films are deposited on the front and back sides of the heterojunction solar cell using a PVD process. In the PVD process, a mask strip is provided on the carrier plate supporting the heterojunction solar cell to form a cutting area on the side of the silicon substrate of the heterojunction solar cell facing the back side without depositing a TCO film, which is then used for subsequent slicing.
[0030] This application also provides a stacked battery module, comprising a plurality of sequentially stacked battery cells, wherein the battery cells are heterojunction quadrilateral battery cells, and the battery cells adopt the heterojunction battery cells as described above.
[0031] Compared with the prior art, the heterojunction solar cell provided in this application has at least the following advantages:
[0032] The passivation structure deposited at the cut surface of the silicon substrate includes a first intrinsic amorphous silicon layer and a silicon nitride layer, with the first intrinsic amorphous silicon layer located between the silicon nitride layer and the silicon substrate. This passivation structure has good passivation effect, is resistant to moisture and acid corrosion, and has high reliability. In addition, passivation structures are deposited around the edges of the front and back sides of the silicon substrate near the cut surface to reduce the conduction leakage problem between adjacent cells after negative spacing stacking of the cells. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a side view of a heterojunction solar cell according to an embodiment of this application;
[0035] Figure 2 This is a side view of a heterojunction solar cell according to another embodiment of this application;
[0036] Figure 3 This is a side view of a heterojunction solar cell before cutting, according to an embodiment of this application.
[0037] Figure 4 This is a front view of the back side of a heterojunction solar cell before cutting, according to an embodiment of this application.
[0038] Figure 5 This is a side view of a heterojunction solar cell after cutting, according to an embodiment of this application.
[0039] Figure 6 This is a side view of a heterojunction solar cell before cutting, according to another embodiment of this application.
[0040] Figure 7 This is a front view of the back side of a heterojunction solar cell before cutting, according to another embodiment of this application.
[0041] Figure 8 This is a side view of a heterojunction solar cell after cutting, according to another embodiment of this application.
[0042] Figure 9 This is a schematic diagram of the structure of a jig holding a stack during the edge passivation process of a heterojunction solar cell according to an embodiment of this application;
[0043] Figure 10 This is a schematic diagram of the structure of the shingled battery assembly according to the first embodiment of this application;
[0044] Figure 11 This is a schematic diagram of the structure of the shingled battery assembly according to the second embodiment of this application;
[0045] Figure 12 This is a schematic diagram of the structure of the shingled battery assembly according to the third embodiment of this application;
[0046] Figure 13 This is a schematic diagram of the structure of the stacked battery assembly according to the fourth embodiment of this application.
[0047] Reference numerals: 10, silicon substrate; 11, front side; 12, back side; 13, side side; 14, cut surface; 15, passivation structure; 16a, first intrinsic amorphous silicon layer; 16b, second intrinsic amorphous silicon layer; 17, silicon nitride layer; 18, edge region; 19, TCO film layer; 20, stack; 21, fixture; 22, P-type amorphous silicon layer; 23, N-type amorphous silicon layer; 24, gate line; 25, solder ribbon; 26, cut area. Detailed Implementation
[0048] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0049] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," "side," "top," "bottom," and similar expressions used in this application's specification are merely for describing various exemplary structural parts and elements of this application. However, their use herein is for illustrative purposes only and is determined based on the exemplary orientations shown in the accompanying drawings, and does not represent the only possible implementation. Since the embodiments disclosed in this application can be arranged in different orientations, these terms indicating orientation are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.
[0050] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0051] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0052] It should be noted that "axial arrangement" means that the overall arrangement direction is along the axial direction, including but not limited to axial extension, and may be at an angle to the axial direction.
[0053] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.
[0054] To address the reliability issues of edge passivation in traditional heterojunction solar cells, this application provides a heterojunction solar cell that employs an edge passivation design of an intrinsic amorphous silicon layer (also known as the i-layer) and a silicon nitride layer (also known as the SiNx layer) to improve the reliability of edge passivation in solar cell cutting.
[0055] First, the basic structure of heterojunction solar cells will be explained.
[0056] The heterojunction solar cell has two opposite outer surfaces along its thickness direction, namely the front surface 11 and the back surface 12. The front surface 11 and the back surface 12 are connected by a side surface 13. The front surface 11 is the light-receiving surface, and the back surface 12 is the back-lighting surface. Figure 3 and Figure 6 As shown, taking the heterojunction solar cell in this embodiment as an example, the upper surface of the solar cell is the front side 11, and the lower surface of the solar cell is the back side 12. The heterojunction solar cell also includes a silicon substrate 10. Between the front side 11 of the solar cell and the upper surface of the silicon substrate 10, there is a TCO film layer 19 (also known as a transparent conductive oxide film), an N-type amorphous silicon layer 23, and a second intrinsic amorphous silicon layer 16b arranged from top to bottom. Between the back side 12 of the solar cell and the lower surface of the silicon substrate 10, there is a TCO film layer 19, a P-type amorphous silicon layer 22, and a second intrinsic amorphous silicon layer 16b arranged from bottom to top. Both the front side 11 and the back side 12 of the solar cell are printed with grid lines 24.
[0057] Of course, a hydrogenated N-type amorphous silicon layer 23 and a hydrogenated second intrinsic amorphous silicon layer 16b can be disposed between the front side 11 of the solar cell and the upper surface of the silicon substrate 10, and a hydrogenated P-type amorphous silicon layer 22 and a hydrogenated second intrinsic amorphous silicon layer 16b can be disposed between the back side 12 of the solar cell and the lower surface of the silicon substrate 10. See also... Figure 4 and Figure 7 During the cell manufacturing process, a TCO film layer 19 is not deposited around the outer edge of the back side 12 of the cell to prevent the TCO film layer 19 on the front side 11 and the back side 12 from short-circuiting on the side.
[0058] Please continue reading Figure 1This application provides a heterojunction solar cell, the side surface 13 of which includes a cut surface 14. The cut surface 14 is provided with a passivation structure 15, and the passivation structure 15 extends towards the front side 11 and the back side 12, such that the passivation structure 15 is provided at the edge position of the front side 11 near the cut surface 14, and at the edge position of the back side 12 near the cut surface 14. The passivation structure 15 includes a first intrinsic amorphous silicon layer 16a and a silicon nitride layer 17 stacked together, the first intrinsic amorphous silicon layer 16a being located between the silicon nitride layer 17 and the silicon substrate 10.
[0059] It is understood that, in order to facilitate the distinction between the intrinsic amorphous silicon layer in the passivation structure 15 and the intrinsic amorphous silicon layer disposed between the front side 11 and the back side 12 of the solar cell and the silicon substrate 10, the intrinsic amorphous silicon layer in the passivation structure 15 is referred to as the first intrinsic amorphous silicon layer 16a, and the intrinsic amorphous silicon layer between the front side 11 and the back side 12 of the solar cell and the silicon substrate 10 is referred to as the second intrinsic amorphous silicon layer 16b.
[0060] Combination Figure 3 , Figure 4 as well as Figure 5 In some embodiments of this application, the heterojunction solar cell is cut along a cutting path SS parallel to the long side direction to obtain a solar cell with a cut surface 14 on the side 13. It should be noted that no grid lines 24 are printed on the front side 11 and back side 12 of the solar cell at the SS path.
[0061] Of course, the cutting path SS can also be parallel to the wide side of the solar cell to meet different solar cell cutting requirements.
[0062] The first intrinsic amorphous silicon layer 16a in the passivation structure 15 can also be a hydrogenated first intrinsic amorphous silicon layer 16a. The nitrogen-to-silicon ratio in the silicon nitride layer 17 can be reasonably adjusted based on passivation requirements and refractive index requirements.
[0063] Compared to the traditional passivation structure of a single intrinsic amorphous silicon layer (i-layer), the passivation structure 15 of this application embodiment adopts a combination of a first intrinsic amorphous silicon layer 16a and a silicon nitride layer 17. The first intrinsic amorphous silicon layer 16a is located between the silicon nitride layer 17 and the silicon substrate 10. At the same time, the passivation structure 15 is deposited around the edge of the front side 11 and back side 12 of the cell near the cutting surface 14. By utilizing the insulation and water resistance of the silicon nitride layer 17, insulation is achieved while protecting the first intrinsic amorphous silicon layer 16a from damage by moisture and other contaminants, improving the reliability of the passivation structure 15 at the cutting edge of the cell, and also reducing the leakage current of the cell during string bonding.
[0064] Please see Figure 2In some embodiments of this application, a portion of the edge of the back surface 12 near the cut surface 14 is defined as edge region 18. Edge region 18 is connected to the cut surface 14, and no TCO film layer 19 is deposited in edge region 18. Since the TCO film layer 19 is both transparent and conductive, not depositing the TCO film layer 19 in edge region 18 near the cut surface 14 of the back surface 12 further reduces leakage current during cell stringing. In other words, a TCO film layer is deposited in all areas of the back surface 12 except for edge region 18 and the outer edge of the back surface 12 as described above.
[0065] Combination Figure 6 , Figure 7 as well as Figure 8 In some embodiments of this application, the back surface 12 of the heterojunction solar cell has a cutting region 26 parallel to the long side direction, and no TCO film layer 19 is deposited in the cutting region 26. The cutting path SS is located in the cutting region 26 and is parallel to the long side of the solar cell. After cutting the solar cell along the cutting path SS, a solar cell with a cutting surface 14 on the side 13 is obtained. At this time, the cutting region 26 forms an edge region 18 at the edge of the cutting surface 14 of the sliced solar cell.
[0066] Similarly, the cutting area 26 can be parallel to the wide side of the solar cell, and the cutting path SS is also parallel to the wide side of the solar cell to meet the needs of cutting more solar cells.
[0067] Furthermore, along the direction perpendicular to the cutting surface 14, i.e. Figure 2 In the XX direction, the width of the edge region 18 is 0.5mm-2mm. In other words, in the XX direction, the width of the non-deposited TCO film layer 19 is 0.5mm-2mm. Within this width range, the insulation requirements for negative spacing stringing of the solar cells are met.
[0068] Please see Figure 1 and Figure 2 Along the direction perpendicular to the cutting surface 14, i.e. Figure 1 or Figure 2 In the XX direction, the width of the passivation structure 15 on the front side 11 is 0.1mm-5mm, and the width of the passivation structure 15 on the back side 12 is 0.1mm-5mm. It is understood that the widths of the passivation structure 15 on the front side 11 and the back side 12 do not need to be exactly the same. For example, the width of the passivation structure 15 on the front side 11 can be 5mm, and the width of the passivation structure 15 on the back side 12 can be 2mm, thus reducing the precision requirements of the passivation structure 15 deposition process.
[0069] In some embodiments of this application, a TCO film layer 19 is deposited on both the side of the silicon substrate 10 facing the front side 11 and the side facing the back side 12. The passivation structure 15 disposed on the front side 11 at least partially covers the TCO film layer 19 on the front side 11 to ensure the insulation effect during negative-pitch string bonding of the solar cells. The passivation structure 15 disposed on the back side 12 at least partially covers the TCO film layer 19 on the back side 12, also for ensuring the insulation effect during negative-pitch string bonding of the solar cells.
[0070] More specifically, when the back side 12 does not have an edge region 18 where the TCO film layer 19 is not deposited, the passivation structure 15 provided on the back side 12 can cover the TCO film layer 19 on the back side 12 to ensure the insulation effect during negative pitch stringing of the solar cells.
[0071] When the back surface 12 has an edge region 18 where no TCO film layer 19 is deposited, the width of the passivation structure 15 deposited around the back surface 12 along the XX direction can be greater than or less than the width of the edge region 18. Preferably, the width of the passivation structure 15 on the back surface 12 is greater than the width of the edge region 18, that is, the passivation structure 15 on the back surface 12 at least partially covers the TCO film layer 19 on the back surface 12 to ensure the insulation effect during negative pitch string bonding of the solar cells.
[0072] Of course, since the back side 12 has an edge region 18 where the TCO film layer 19 is not deposited, it provides a certain degree of isolation and insulation for negative-pitch string bonding of the solar cells. The width of the passivation structure 15 on the back side 12 can also be smaller than the width of the edge region 18 to meet more application requirements.
[0073] This application also provides an edge passivation method for heterojunction solar cells, used to passivate the edges of the cut surface 14 of the heterojunction solar cell in any of the above embodiments. Specifically, in conjunction with Figure 9 The edge passivation method includes the following steps:
[0074] Multiple cut heterojunction solar cells are stacked along their thickness direction to form a stack 20. The cut surfaces 14 of each heterojunction solar cell face the same direction, and the thickness direction of the stack 20 is consistent with the thickness direction of the heterojunction solar cells. There are gaps between adjacent heterojunction solar cells. Specifically, in actual production, dozens or even hundreds of solar cells are stacked together. Adjacent solar cells will naturally sag under the action of gravity, and the grid lines 24 of adjacent solar cells will provide support, thus forming gaps between the solar cells in a naturally stacked state.
[0075] The stack 20 is placed in the clamp 21, and the clamp 21 clamps the stack 20 along the thickness direction to ensure the stability of the battery cells in the subsequent edge passivation process and ensure the passivation effect.
[0076] Using a hot-wire CVD device, a passivation structure 15 is deposited on the cut surface 14 of the heterojunction solar cells in the stack 20. During the deposition process, the passivation structure 15 is penetrated into the gaps between the heterojunction solar cells to deposit the passivation structure 15 around the edges of the front side 11 and back side 12 of the heterojunction solar cells near the cut surface 14.
[0077] Furthermore, before depositing the passivation structure 15, the gap between the heterojunction solar cells is adjusted by regulating the clamping pressure of the jig 21 on the heterojunction solar cells. It is understood that applying clamping pressure to the heterojunction solar cells with the jig 21 causes deformation of the cells, thereby adjusting the gap between them. Changes in the gap between the cells affect the width of the passivation structure 15 deposited around the front side 11 and the back side 12, thus depositing a passivation structure 15 of appropriate width on the edges of the front side 11 and the back side 12 near the cut surface 14. This allows for process control of the passivation structure 15 deposited around the front side 11 and the back side 12; specifically, it allows for controllable width of the passivation structure 15 deposited around the front side 11 and the back side 12.
[0078] The clamping pressure of the clamps 21 on the heterojunction solar cells and the gap between adjacent heterojunction solar cells satisfy the following:
[0079] D = F × (d1 + d2 + d3) × M × X;
[0080] S = [(d1 + d2 + d3) × MD] / (M - 1);
[0081] D is the total thickness of the stacked heterojunction solar cells;
[0082] F represents the clamping pressure of the 21 pairs of heterojunction solar cells in the clamp;
[0083] d1 represents the thickness of a single heterojunction solar cell after the TCO film layer 19 is deposited by the PVD process;
[0084] d2 is the height of the grid line 24 on the front side 11 of the finished heterojunction solar cell;
[0085] d3 is the height of the grid line 24 on the back side 12 of the finished heterojunction solar cell;
[0086] M represents the number of heterojunction solar cells;
[0087] X is the correction factor;
[0088] S represents the gap between adjacent heterojunction solar cells.
[0089] The passivation structure 15 of the front side 11 and the back side 12 of the heterojunction solar cell both satisfy the following requirements:
[0090] L = x1 × S;
[0091] L represents the width of the passivation structure 15 around the front side 11 or back side 12 of the heterojunction solar cell.
[0092] x1 is the fitting coefficient.
[0093] Combination Figures 6 to 8 In some embodiments of this application, the front side 11 and back side 12 of the heterojunction solar cell are deposited with a TCO film 19 by a PVD process. In the PVD process, a mask strip is provided on the carrier plate carrying the heterojunction solar cell to form a cutting area 26 on the side of the silicon substrate 10 of the heterojunction solar cell facing the back side 12 where the TCO film 19 is not deposited, and for subsequent slicing. The width of the cutting area 26 is determined according to the width of the edge area 18 formed on the back side 12 of the solar cell after subsequent slicing.
[0094] This application also provides a stacked solar cell assembly, including a plurality of solar cells stacked sequentially, wherein the solar cells are heterojunction solar cells of any of the above embodiments, thereby reducing leakage current during negative pitch stacking.
[0095] Specifically, this application provides the following embodiments.
[0096] Example 1:
[0097] See Figure 10 In this embodiment, a heterojunction solar cell is used where the edge region 18 of the back side 12 is not provided for depositing the TCO film layer 19. In the stacked solar cell assembly of this embodiment, the edge of the back side 12 of the solar cell near the cut surface 14 is used to stack another solar cell downwards.
[0098] Example 2:
[0099] See Figure 11 In this embodiment, a heterojunction solar cell is used where the edge region 18 on the back side 12 is not provided for depositing the TCO film layer 19. The difference from Embodiment 1 is that in the stacked solar cell assembly of this embodiment, the edge of the front side 11 of the solar cell near the cut surface 14 is used to stack another solar cell upwards.
[0100] Example 3:
[0101] See Figure 12 In this embodiment, a heterojunction solar cell with an edge region 18 on the back side 12 where no TCO film layer 19 is deposited is used. In the tandem solar cell assembly of this embodiment, the edge of the front side 11 of the solar cell near the cut surface 14 is used to tandem another solar cell upwards.
[0102] Example 4:
[0103] See Figure 13In this embodiment, a heterojunction solar cell with an edge region 18 on the back side 12 where no TCO film layer 19 is deposited is used. The difference from Embodiment 3 is that adjacent solar cells are connected by solder strips 25.
[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0105] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.
Claims
1. A heterojunction solar cell, wherein two outer surfaces of the heterojunction solar cell, which are opposite to each other along its thickness direction, are a front surface and a back surface, wherein the front surface and the back surface are connected by a side surface, characterized in that, The side surface includes a cut surface, the cut surface is provided with a passivation structure and the passivation structure extends to the front side and the back side, so that the passivation structure is provided at the edge position of the front side near the cut surface and the edge position of the back side near the cut surface. The passivation structure includes a first intrinsic amorphous silicon layer and a silicon nitride layer stacked together. The heterojunction solar cell includes a silicon substrate, and the first intrinsic amorphous silicon layer is located between the silicon nitride layer and the silicon substrate.
2. The heterojunction solar cell according to claim 1, characterized in that, A portion of the area on the back side near the cut surface is defined as the edge region, which is in contact with the cut surface, and no TCO film is deposited in the edge region.
3. The heterojunction solar cell according to claim 2, characterized in that, Along the direction perpendicular to the cut surface, the width of the edge region is 0.5mm-2mm.
4. The heterojunction solar cell according to any one of claims 1 to 3, characterized in that, Along the direction perpendicular to the cut surface, the width of the passivation structure on the front side is 0.1mm-5mm, and the width of the passivation structure on the back side is 0.1mm-5mm.
5. The heterojunction solar cell according to claim 4, characterized in that, The silicon substrate has TCO films deposited on both the side facing the front and the side facing the back. The passivation structure on the front side at least partially covers the TCO film on the front side, and the passivation structure on the back side at least partially covers the TCO film on the back side.
6. A method for edge passivation of a heterojunction solar cell, characterized in that, An edge passivation method for the cut surface of a heterojunction solar cell according to any one of claims 1 to 5, the edge passivation method comprising the following steps: Multiple cut heterojunction solar cells are stacked along the thickness direction of the heterojunction solar cells to form a stack. The cut surfaces of each heterojunction solar cell face the same direction. The thickness direction of the stack is consistent with the thickness direction of the heterojunction solar cells. There are gaps between adjacent heterojunction solar cells. The stack is placed in the fixture, and the fixture clamps the stack along the thickness direction of the stack. A hot-wire CVD device is used to deposit passivation structures on the cut surfaces of heterojunction solar cells in a stack. During the deposition process, the passivation structures are penetrated into the gaps between the heterojunction solar cells to deposit passivation structures around the edges of the front and back sides of the heterojunction solar cells near the cut surfaces.
7. The edge passivation method for heterojunction solar cells according to claim 6, characterized in that, Before depositing the passivation structure, the gap between the heterojunction solar cells is adjusted by adjusting the clamping pressure of the clamp on the heterojunction solar cells.
8. The edge passivation method for heterojunction solar cells according to claim 7, characterized in that, The clamping pressure of the fixture on the heterojunction solar cell and the gap between adjacent heterojunction solar cells satisfy the following: D = F × (d1 + d2 + d3) × M × X; S = [(d1 + d2 + d3) × MD] / (M - 1); D is the total thickness of the stacked heterojunction solar cells; F represents the clamping pressure of the fixture on the heterojunction solar cell; d1 represents the thickness of a single heterojunction solar cell after the TCO film is deposited using the PVD process. d2 is the grid line height on the front side of the finished heterojunction solar cell; d3 is the grid line height on the back of the finished heterojunction solar cell; M represents the number of heterojunction solar cells; X is the correction factor; S is the gap between adjacent heterojunction solar cells; The passivation structure wrap-around widths on both the front and back sides of the heterojunction solar cell meet the following requirements: L = x1 × S; L represents the width of the passivation structure on the front or back of the heterojunction solar cell. x1 is the fitting coefficient.
9. The edge passivation method for heterojunction solar cells according to claim 8, characterized in that, The front and back sides of the heterojunction solar cell are deposited with TCO film layers through PVD process. In the PVD process, a mask strip is provided on the carrier plate carrying the heterojunction solar cell to form a cutting area on the side of the silicon substrate of the heterojunction solar cell facing the back side without depositing TCO film layer, which is used for subsequent slicing.
10. A shingled battery module, characterized in that, It includes multiple sequentially stacked solar cells, wherein the solar cells are heterojunction quadrilateral solar cells, and the solar cells are heterojunction solar cells as described in any one of claims 1 to 5.