Solar cell and solar cell string

Abstract

The application provides a solar cell and a solar cell string, which comprise a cell body and a sub-grid structure arranged on a first surface of the cell body, the first surface of the cell body is divided into a normal area and a reinforcing area surrounding the normal area; the sub-grid structure comprises at least four first sub-grid lines parallel to each other, a center section of the first sub-grid line and edge sections on both sides of the center section are located in the normal area and the reinforcing area respectively; the average cross-sectional area of the first sub-grid line at different positions of the edge sections is a first area; the average cross-sectional area of the first sub-grid line at different positions of the center section is a second area, and the first area is greater than the second area. The solar cell provided by the application can delay the speed of power output attenuation of the solar cell.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to a solar cell and a solar cell string. Background Technology

[0002] Photovoltaic energy has become an important component of the human energy structure, and the core factor driving its large-scale application stems from the continuous decline in the levelized cost of electricity (LCOE). This decline is primarily due to the development and industrial application of high-efficiency and low-cost technologies. However, the application of these technologies presupposes that the modules also possess high reliability; therefore, research into high-reliability technologies is a crucial area for researchers in photovoltaic module and battery technology to explore.

[0003] Currently, photovoltaic modules using backsheet encapsulation structures employ a low-loss metallization design for the fine grid paste on the front side of the cells. However, as usage time increases, the power output of these modules degrades, with the degradation being more severe in humid environments. Therefore, how to slow down the power output degradation of photovoltaic modules is a pressing issue that needs to be addressed. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a solar cell and solar cell string that can reduce the blackening phenomenon at the edge of the cell, delay the increase of the line resistance of the sub-grid line and the contact resistance between the sub-grid line and the cell surface, and slow down the rate of power output decay of the solar cell.

[0005] To achieve the purpose of this invention, a solar cell is provided, comprising a cell body and a sub-grid structure disposed on a first surface of the cell body, wherein the first surface of the cell body is divided into a conventional region and a reinforcing region surrounding the conventional region;

[0006] The sub-gate structure includes at least four first sub-gate lines that are parallel to each other, wherein the central segment of the first sub-gate line and the edge segments located on both sides of the central segment are located in the conventional region and the reinforced region, respectively;

[0007] The average cross-sectional area at different positions on the edge segment of the first sub-gate line is the first area; the average cross-sectional area at different positions on the center segment of the first sub-gate line is the second area, and the first area is greater than the second area.

[0008] Optionally, the sub-gate structure further includes at least four second sub-gate lines parallel to the first sub-gate line, all of which are located in the reinforcement region; the average cross-sectional area at different positions of the second sub-gate lines is a third area, which is greater than the second area.

[0009] Optionally, the ratio of the first area to the second area is greater than 1 and less than or equal to 3; the ratio of the third area to the second area is greater than 1 and less than or equal to 3.

[0010] Optionally, the value of the first area ranges from 0.0001 to 0.001 mm. 2 The value of the third area ranges from 0.0001 to 0.001 mm. 2 The value of the second area ranges from 0.000045 to 0.00075 mm. 2 .

[0011] Optionally, the distance L between the boundary between the conventional region and the reinforced region and the corresponding edge of the battery cell body satisfies the following relationship:

[0012]

[0013] Where A1 is the second area; C1 is the lower limit coefficient of the distance L, and the lower limit coefficient is 0.0001mm. 3 C2 is the upper limit coefficient of the distance L, and the upper limit coefficient is 0.01mm. 3 .

[0014] Optionally, the cross-sectional area is the same at different positions on the edge segment of the first sub-gate line.

[0015] Optionally, the edge segment of the first sub-gate line is divided into multiple sub-edge segments along its extension direction. The cross-sectional area of ​​each sub-edge segment is the same at different positions, and the cross-sectional area of ​​the multiple sub-edge segments decreases sequentially from the boundary of the reinforced region to the intersection of the corresponding conventional region and the reinforced region.

[0016] Optionally, the cross-sectional area at different positions of the edge segment of the first sub-gate line decreases linearly or non-linearly from the boundary of the reinforced region to the corresponding boundary between the conventional region and the reinforced region.

[0017] Optionally, the cross-sectional area of ​​the second sub-grid line is the same at different locations.

[0018] Optionally, the sub-gate structure further includes a third sub-gate line parallel to the first sub-gate line, at least one of the third sub-gate lines being located in the reinforcement region, and / or the central segment and the edge segments located on both sides of the central segment of at least one third sub-gate line being located in the conventional region and the reinforcement region, respectively;

[0019] The average cross-sectional area at different locations of the third sub-grid line is the same as that of the first sub-grid line.

[0020] As another technical solution, this embodiment of the invention also provides a solar cell string array, including multiple solar cell strings, each of which includes multiple solar cell wafers provided in this embodiment of the invention, and the multiple solar cell wafers are electrically connected.

[0021] The present invention has the following beneficial effects:

[0022] The solar cell provided by the present invention divides the first surface of the cell body into a conventional region and a reinforced region surrounding the conventional region. By making the average cross-sectional area (i.e., the first area) at different positions of the edge segment of a single first sub-grid line located in the reinforced region greater than the average cross-sectional area (i.e., the second area) at different positions of the center segment of a single first sub-grid line located in the conventional region, the consumption of at least a portion of the sub-grid paste in the reinforced region can be increased relative to the sub-grid in the conventional region. This increases the path for water vapor to penetrate from the outer surface of the sub-grid line into the interior, delays the occurrence of grid line corrosion, and further delays the increase in the line resistance of the sub-grid line and the contact resistance between the sub-grid line and the cell surface, thereby slowing down the rate of power output decay of the solar cell.

[0023] The solar cell string provided by the present invention, by employing the solar cell provided by the present invention, can delay the increase of the line resistance of the sub-grid lines and the contact resistance between the sub-grid lines and the cell surface, thereby slowing down the rate of power output decay of the solar cell. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the path of water vapor penetrating into the interior of a photovoltaic module through the backsheet in a direction perpendicular to the surface of the solar cells.

[0025] Figure 2 This is a schematic diagram of the path of water vapor penetrating into the interior of a photovoltaic module through the backsheet in a direction parallel to the surface of the solar cells.

[0026] Figure 3A This is a front view of one of the main bodies of an existing solar cell.

[0027] Figure 3B Electroluminescence diagram of existing solar cells after damp heat testing;

[0028] Figure 4A A front view of one of the main bodies of a solar cell provided in an embodiment of the present invention;

[0029] Figure 4B This is a schematic diagram of the structure of a battery string composed of solar cells provided in an embodiment of the present invention;

[0030] Figure 4C Another front view of one of the main bodies of a solar cell provided in an embodiment of the present invention;

[0031] Figure 5 This is a comparison diagram of the cross-sections of the center segment and the edge segment of the first grid line used in an embodiment of the present invention;

[0032] Figure 6 This is a comparison diagram of cross-sections showing different shapes of the center segment and edge segment of the first grid line used in an embodiment of the present invention;

[0033] Figure 7 This is a comparison diagram of the axial cross-sections of the center segment and edge segments of different shapes of the first grid line used in an embodiment of the present invention;

[0034] Figure 8 This is a comparison diagram of the cross-sectional area curves of the center segment and edge segments of different shapes of the first sub-grid line used in the embodiments of the present invention.

[0035] Figure 9 The electroluminescence pattern of the solar cell provided in the embodiment of the present invention after undergoing a damp heat test. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of the present invention, the solar cell and solar cell string provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0037] The inventors discovered that current photovoltaic modules using backsheet encapsulation structures employ a low-loss metallization design for the fine grid paste on the front side of the cells, such as... Figure 1 and Figure 2 As shown, when photovoltaic modules operate in a humid and hot environment for a long time, moisture will continuously seep into the module through the backsheet on the back of the module, and gradually diffuse towards the center area along the edge of the front of the cell through the gap between the cells. This will cause the contact resistance between the sub-busbar and the silicon wafer to increase, resulting in a decrease in the power output of the photovoltaic module.

[0038] Figure 3A This is a front view of one of the main body cells of an existing solar cell. Figure 3A As shown, the cross-sectional area of ​​each sub-grid line on the main body of the solar cell is the same at different locations. Figure 3B for Figure 3A The image shown is an EL image of a solar cell after a damp heat test. Figure 3BIt is evident that there is a noticeable blackening at the edge of each cell body. This phenomenon is due to the fact that high concentrations of water vapor are more likely to accumulate at the edge of the front side of the cell. The water vapor accelerates the precipitation of acidic components in the encapsulation material, resulting in obvious grid line corrosion at the edge of the front side (i.e., the light-receiving side) of the cell. This causes an increase in the contact resistance between the sub-grid and the silicon wafer, resulting in a decrease in the power output of the photovoltaic module.

[0039] To resolve the above issues, please refer to Figure 4A This invention provides a solar cell comprising a cell body 1 and a sub-grid structure disposed on a first surface of the cell body 1, the first surface being, for example, the light-receiving surface (also referred to as the front surface) of the cell body 1. The cell body 1 is the smallest cell unit of the solar cell. Figure 4A Only a single cell body 1 and the sub-grid structure located on its first surface are shown.

[0040] The first surface of the battery cell body 1 is divided into a conventional region E0 and a reinforcing region E1 surrounding the conventional region E0. Optionally, the conventional region E0 is the central region of the first surface, and the reinforcing region E1 is the annular edge region surrounding the central region. The sub-grid structure includes at least four parallel first sub-grid lines 3. The central segment 31 and the edge segments 32 located on both sides of the central segment 31 are located in the conventional region E0 and the reinforcing region E1, respectively. That is, each first sub-grid line 3 intersects the boundary between the conventional region E0 and the reinforcing region E1 and is divided into three segments.

[0041] The average cross-sectional area at different positions of the edge segment 32 of a single first sub-gate line 3 is the first area; the average cross-sectional area at different positions of the center segment 31 of a single first sub-gate line 3 is the second area, and the first area is greater than the second area. The average cross-sectional area at different positions of the edge segment 32 of the first sub-gate line 3 is the quotient of the sum of the cross-sectional areas of the edge segment 32 at M different positions in its extension direction, divided by M, where M is an integer greater than 1; the average cross-sectional area at different positions of the center segment 31 of the first sub-gate line 3 is the quotient of the sum of the cross-sectional areas of the center segment 31 at R different positions in its extension direction, divided by R, where R is an integer greater than 1.

[0042] By making the average cross-sectional area (i.e., the first area) at different positions of the edge segment 32 of a single first sub-grid line 3 located in the reinforced region greater than the average cross-sectional area (i.e., the second area) at different positions of the center segment 31 of a single first sub-grid line 3 located in the conventional region E0, it is possible to increase the unit consumption of at least a portion of the sub-grid slurry in the reinforced region E1 relative to the conventional region E0, while keeping the unit consumption in the conventional region E0 unchanged. That is, by increasing the average cross-sectional area at different positions of the edge segment 32 of a single first sub-grid line 3 located in the reinforced region E1, under the same water vapor corrosion depth, this A larger average cross-sectional area results in a higher retention rate of the sub-grid resistance and its surface contact resistance with the cell body 1. In other words, even if the sub-grid lines in the enhanced region E1 are corroded to a certain extent, the line resistance and surface contact resistance will not rise rapidly. Under the same corrosion conditions, sub-grid lines with a larger average cross-sectional area exhibit a slower increase in line resistance and surface contact resistance. Furthermore, increasing the average cross-sectional area of ​​the sub-grid lines also increases the path for moisture to penetrate from the outer surface of the sub-grid lines into the interior, delaying grid line corrosion and thus slowing down the rate of power output degradation in the solar cell. In addition, by using a smaller average cross-sectional area for the sub-grid lines in the conventional region E0, the unit power consumption in this region can be reduced, thereby lowering the cost of the cell.

[0043] It should be noted that in practical applications, Figure 4A The intermediate sub-gate structure (including at least four parallel first sub-gate lines 3) can be applied to Figure 4B The solar cell string shown is composed of multiple solar cells stacked together. The stacking area is the blank area in the reinforcement area E1, excluding the area where the edge segment 32 of the first sub-grid line 3 is located. Since this stacking area is covered by another solar cell, it can play a role in isolating moisture. In this case, a sub-grid line can be set in the blank area in the reinforcement area E1 excluding the area where the edge segment 32 of the first sub-grid line 3 is located, or no sub-grid line can be set.

[0044] In some alternative embodiments, such as Figure 4C As shown, the aforementioned sub-gate structure, in addition to the first sub-gate line 3, also includes at least four second sub-gate lines 2 parallel to the first sub-gate line 3. All four second sub-gate lines 2 are located in the reinforcement region E1 (i.e., in the aforementioned blank region). The boundary between each second sub-gate line 2 and its nearest reinforcement region E1 and the conventional region E0 is parallel. The average cross-sectional area at different positions of a single second sub-gate line 2 is the third area, which is the quotient of the sum of the cross-sectional areas of N different positions of a single second sub-gate line 2 in its extension direction divided by N, where N is an integer greater than 1. The second sub-gate lines 2 can effectively isolate water vapor in the aforementioned blank region. Moreover, Figure 4CThe subgate structure shown can be applied to Figure 4B The solar cell string shown can also be used for Figure 1 and Figure 2 The image shows a string of solar cells (multiple solar cells spaced apart).

[0045] In some optional embodiments, the ratio of the first area to the second area is greater than 1 and less than or equal to 3; the ratio of the third area to the second area is greater than 1 and less than or equal to 3. By setting the ratios within this range, the unit consumption of at least a portion of the sub-grid paste in the reinforced region E1 can be effectively increased, while excessive unit consumption in this region can be avoided, thereby reducing battery costs. Optionally, the value range of the first area is 0.0001 to 0.001 mm. 2 The value of the third area mentioned above ranges from 0.0001 to 0.001 mm. 2 The value range of the second area mentioned above is 0.000045 to 0.00075 mm. 2 .

[0046] In some optional embodiments, the distance L between the boundary between the conventional region E0 and the reinforced region E1 and the corresponding edge (parallel to the boundary line) of the battery cell body 1 satisfies the following relationship:

[0047]

[0048] Where A1 is the second area mentioned above (unit: mm). 2 C1 is the lower limit coefficient for distance L, which is 0.0001 mm. 3 C2 is the upper limit coefficient for distance L, with an upper limit coefficient of 0.01 mm. 3 .

[0049] By ensuring that the distance L satisfies the aforementioned relationship, it is possible to prevent a high concentration of water vapor from penetrating the reinforced region E1 and causing corrosion of the sub-grid lines in the conventional region E0, and also to avoid excessive consumption of the sub-grid paste in the reinforced region E1, thereby reducing battery costs. It should be noted that the boundary of the reinforced region E1 is typically located near the edge of the cell body 1. However, in practical applications, the boundary of the reinforced region E1 can be aligned with the edge of the cell body 1, depending on specific needs.

[0050] It should be noted that in practical applications, the aforementioned distance L can be set according to factors such as the composition, structure, and size of the secondary grid line (i.e., the central segment 31 of the first secondary grid line 3) in the conventional area E0. For example, when the height and width of the secondary grid line in the conventional area E0 are very small, the distance L needs to be increased accordingly; conversely, the distance L can be decreased accordingly, as long as the secondary grid line in the reinforced area E1 has sufficient waterproof effect to prevent the penetration of large concentrations of water vapor. Optionally, the distance L can be, for example, equal to 20mm or 30mm.

[0051] There are various ways to achieve the first area being larger than the second area, and the third area being larger than the second area. For example, the width and height of the sub-gate lines can be increased, or a cross-sectional shape with a larger cross-sectional area can be used. In a specific embodiment, such as... Figure 5 As shown, the cross-sectional shape of the center segment 31 and the edge segment 32 of the first sub-gate line 3 is an isosceles trapezoid. Furthermore, the width B2 of the edge segment 32 of the first sub-gate line 3 is greater than the width B1 of the center segment 31, and the height H2 of the edge segment 32 of the first sub-gate line 3 is greater than the height H1 of the center segment 31, thereby achieving a first area greater than the second area. The implementation method of the third area being greater than the second area is the same as in this specific embodiment.

[0052] In some optional embodiments, the cross-sectional shape of the first sub-grid line 3 can be the same or different; the cross-sectional shape of the second sub-grid line 2 can be the same or different. Furthermore, the cross-sectional shape can be, in addition to being an isosceles trapezoid, other shapes including but not limited to... Figure 6 The five cross-sectional shapes shown in the figure have outlines that are in contact with the first surface of the battery cell body 1. These outlines can be straight lines, while the outlines that are not in contact with the first surface can include sinusoidal shapes, arcs, semicircles, rectangles, irregular broken lines, curves, triangles, polygons, combinations of curves and straight lines, and so on. The embodiments of the present invention do not have any particular limitations on this.

[0053] In some alternative embodiments, such as Figure 7 Figure (a) and Figure 8 As shown in Figure (a), Figure 8 In Figure (a), the vertical axis A represents the cross-sectional area of ​​the subgrid line; Figure 8 In Figure (a), the horizontal coordinate D represents the distance between different positions on any sub-grid line and the corresponding edge of the main body 1 of the solar cell. In the region corresponding to D < L, the cross-sectional area of ​​the edge segment 32 of a single first sub-grid line 3 is the same at different positions, which is A2 (i.e., the first area); in the region corresponding to D ≥ L, the cross-sectional area of ​​the center segment 31 is the same at different positions, which is A1 (i.e., the second area), and A2 is greater than A1. Optionally, A2 / A1 is greater than 1 and less than or equal to 3.

[0054] In one specific embodiment, the aforementioned distance L is equal to 20 mm; the cross-sectional shapes of both the center segment 31 and the edge segment 32 are isosceles trapezoids, and the average width of the cross-section of the center segment 31 at different positions in the conventional region E0 is 30 μm, and the average height is 6 μm; the average width of the cross-section of the edge segment 32 in the reinforced region E1 is 35 μm, and the average height is 7 μm. The cross-sectional design of the second sub-grid line 2 is the same as that of the edge segment 32. After conducting a periodic damp heat test using this sub-grid structure, as... Figure 9 As shown, the problem of edge blackening of each cell body in the solar cell is significantly reduced, and the power output degradation is reduced from... Figure 3B The level of cell degradation shown was 5%–10%, which decreased to less than 3%.

[0055] In other alternative embodiments, the cross-sectional area of ​​the edge segment 32 of a single first sub-gate line 3 at different locations can also be different. There are many different ways to do this. For example, the edge segment 32 of the first sub-gate line 3 can be divided into multiple sub-edge segments along its extension direction, wherein the cross-sectional area of ​​each sub-edge segment at different locations is the same, and the cross-sectional area of ​​the multiple sub-edge segments decreases sequentially from the boundary of the reinforcing region E1 towards the intersection of the corresponding conventional region E0 and the reinforcing region E1. Specifically, Figure 8 In Figure (b), the vertical axis A represents the cross-sectional area of ​​the sub-grid line; Figure 8 In Figure (b), the horizontal axis D represents the distance between different positions on any sub-grid line and the edge of the corresponding cell body 1. For example... Figure 7 Figure (b) in the middle and Figure 8 As shown in Figure (b), the edge segment 32 of a single first sub-gate line 3 is divided into two sub-edge segments (32a, 32b) along its extension direction. In the region corresponding to D < L1, the cross-sectional area of ​​sub-edge segment 32a at different positions is the same, which is A. 2max In the region corresponding to L1≤D<L, the cross-sectional area of ​​sub-edge segment 32b at different locations is the same, which is A. 2min And A 2min <A 2max In the region corresponding to D≥L, the cross-sectional area of ​​the central segment 31 at different locations is the same, which is A1, and A 2min Greater than A1. Optional, (A 2max +A 2min ) / 2A1 is greater than 1 and less than or equal to 3.

[0056] For example, the cross-sectional area of ​​the edge segment 32 of a single first sub-gate line 3 at different locations decreases linearly from the boundary of the reinforced region E1 to the boundary between the corresponding normal region E0 and the reinforced region E1. Specifically, Figure 8 In figure (c), the vertical axis A represents the cross-sectional area of ​​the sub-grid line; Figure 8In Figure (c), the horizontal axis D represents the distance between different positions on any sub-grid line and the edge of the corresponding cell body 1. For example... Figure 7 Figure (c) in the middle and Figure 8 As shown in Figure (c), in the region corresponding to D < L, the cross-sectional area of ​​the edge segment 32 of a single first sub-gate line 3 on the boundary of the reinforcement region E1 is the maximum value A. 2max Furthermore, as it approaches the boundary between the normal region E0 and the enhanced region E1, the cross-sectional area decreases linearly. In the region corresponding to D≥L, the cross-sectional area at different locations of the central segment 31 is the same, which is A1, and A 2max Greater than A1.

[0057] Similarly, the cross-sectional area of ​​the edge segment 32 of a single first sub-gate line 3 at different locations can also decrease non-linearly from the boundary of the enhanced region E1 to the boundary of the normal region E0. Specifically, Figure 8 In figure (d), the vertical axis A represents the cross-sectional area of ​​the sub-grid line; Figure 8 In diagram (d), the horizontal axis D represents the distance between different positions on any sub-grid line and the edge of the corresponding cell body 1. For example... Figure 7 Figure (d) in the middle and Figure 8 As shown in Figure (d), in the region corresponding to D < L, the cross-sectional area of ​​the edge segment 32 of a single first sub-gate line 3 on the boundary of the reinforcement region E1 is the maximum value A. 2max Furthermore, as it approaches the boundary between the normal region E0 and the enhanced region E1, the cross-sectional area decreases non-linearly (e.g., by a curve). In the region corresponding to D≥L, the cross-sectional area at different locations of the central segment 31 is the same, A1, and A 2max Greater than A1.

[0058] In some optional embodiments, to simplify the manufacturing process and reduce costs, the cross-sectional area of ​​a single second sub-gate line 2 is the same at different locations; this cross-sectional area is referred to as the third area. Of course, in practical applications, the cross-sectional area of ​​a single second sub-gate line 2 at different locations can also be different.

[0059] In some optional embodiments, a third sub-grid line parallel to the first sub-grid line 3 can be added. At least one third sub-grid line can be located in the reinforced region E1, and / or, the central segment and the edge segments on both sides of the central segment of at least one third sub-grid line are located in the conventional region E0 and the reinforced region E1, respectively. The average cross-sectional area of ​​a single third sub-grid line at different locations is the same as the first area mentioned above, that is, the reinforced region E1 can also contain sub-grid lines with lower energy consumption. With the help of the third sub-grid line, the grid line arrangement density can be increased or other specific requirements can be met while ensuring that the sub-grid lines in the reinforced region E1 have sufficient waterproof effect. The cross-sectional design of the third sub-grid line can be consistent with the cross-sectional design of the sub-grid lines in the conventional region E0.

[0060] The solar cell provided in this embodiment of the invention can be applied, for example, to a TOPCon structure solar cell.

[0061] In summary, the solar cell provided by the embodiments of the present invention divides the first surface of the cell body into a conventional region and a reinforced region surrounding the conventional region. By making the average cross-sectional area (i.e., the first area) at different positions of the edge segment of a single first sub-grid line located in the reinforced region greater than the average cross-sectional area (i.e., the second area) at different positions of the center segment of a single first sub-grid line located in the conventional region, the consumption of at least a portion of the sub-grid paste in the reinforced region can be increased relative to the sub-grid in the conventional region. This increases the path for water vapor to penetrate from the outer surface of the sub-grid line into the interior, delays the occurrence of grid line corrosion, and further delays the increase in the line resistance of the sub-grid line and the contact resistance between the sub-grid line and the cell surface, thereby slowing down the rate of power output decay of the solar cell.

[0062] As another technical solution, this embodiment of the invention also provides a solar cell string array, including multiple solar cell strings, each of which includes the solar cell provided in this embodiment of the invention, and the multiple solar cell sheets are electrically connected (e.g., in parallel or in series).

[0063] In some alternative embodiments, multiple solar cells can be arranged at intervals, such as... Figure 1 and Figure 2 As shown; or, multiple solar cells are stacked and welded together, such as... Figure 4B As shown.

[0064] The solar cell string provided in this embodiment of the invention, by employing the solar cell provided in this embodiment of the invention, can delay the increase of the line resistance of the sub-grid lines and the contact resistance between the sub-grid lines and the cell surface, thereby slowing down the rate of power output decay of the solar cell.

[0065] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A solar cell, characterized in that, The device includes a battery cell body and a sub-grid structure disposed on a first surface of the battery cell body. The first surface of the battery cell body is divided into a conventional region and a reinforcing region surrounding the conventional region. The conventional region is the central region of the first surface, and the reinforcing region is an annular edge region surrounding the central region. The sub-gate structure includes at least four first sub-gate lines that are parallel to each other, wherein the central segment of the first sub-gate line and the edge segments located on both sides of the central segment are located in the conventional region and the reinforced region, respectively; The average cross-sectional area at different positions on the edge segment of the first sub-gate line is the first area; the average cross-sectional area at different positions on the center segment of the first sub-gate line is the second area, and the first area is greater than the second area; The sub-gate structure further includes at least four second sub-gate lines parallel to the first sub-gate line, all of which are located in the reinforcement region; the average cross-sectional area of ​​the second sub-gate lines at different positions is a third area, which is larger than the second area; The distance L between the boundary between the conventional region and the reinforced region and the corresponding edge of the battery cell body satisfies the following relationship: Where A1 is the second area; C1 is the lower limit coefficient of the distance L, and the lower limit coefficient is 0.0001mm. 3 C2 is the upper limit coefficient of the distance L, and the upper limit coefficient is 0.01mm. 3 .

2. The solar cell according to claim 1, characterized in that, The ratio of the first area to the second area is greater than 1 and less than or equal to 3; the ratio of the third area to the second area is greater than 1 and less than or equal to 3.

3. The solar cell according to claim 2, characterized in that, The value of the first area ranges from 0.0001 to 0.001 mm. 2 The value of the third area ranges from 0.0001 to 0.001 mm. 2 The value of the second area ranges from 0.000045 to 0.00075 mm. 2 .

4. The solar cell according to any one of claims 1-3, characterized in that, The cross-sectional area is the same at different positions on the edge segment of the first sub-gate line.

5. The solar cell according to any one of claims 1-3, characterized in that, The edge segment of the first sub-gate line is divided into multiple sub-edge segments along its extension direction. The cross-sectional area of ​​each sub-edge segment is the same at different positions, and the cross-sectional area of ​​the multiple sub-edge segments decreases sequentially from the boundary of the reinforced region to the intersection of the corresponding conventional region and the reinforced region.

6. The solar cell according to any one of claims 1-3, characterized in that, The cross-sectional area of ​​the edge segment of the first sub-gate line at different locations decreases linearly or non-linearly from the boundary of the reinforced region to the intersection of the corresponding conventional region and the reinforced region.

7. The solar cell according to any one of claims 1-3, characterized in that, The cross-sectional area of ​​the second sub-grid line is the same at different locations.

8. The solar cell according to any one of claims 1-3, characterized in that, The sub-gate structure further includes a third sub-gate line parallel to the first sub-gate line, at least one of the third sub-gate lines is located in the reinforcement region, and / or the central segment and the edge segments located on both sides of the central segment of at least one third sub-gate line are located in the conventional region and the reinforcement region, respectively; The average cross-sectional area at different locations of the third sub-grid line is the same as that of the first sub-grid line.

9. A solar cell string array, comprising multiple solar cell strings, characterized in that, Each of the solar cell strings includes a plurality of solar cells as described in any one of claims 1 to 8, and the plurality of solar cells are electrically connected.

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