Back contact cells, cell assemblies and photovoltaic systems

Abstract

The application is suitable for the technical field of solar cells, and provides a back contact cell, a cell module and a photovoltaic system. The back contact cell comprises a silicon substrate, a first edge main grid and a second edge main grid, the first edge main grid and the second edge main grid are different in polarity; the silicon substrate has opposite first and second edges in a first direction; the first edge main grid comprises first and second connecting grid lines connected to each other, the second connecting grid line extends along a second direction, the extension direction of the first connecting grid line is different from the second direction, and the second direction intersects the first direction; the second edge main grid comprises third and fourth connecting grid lines connected to each other, the fourth connecting grid line extends along the second direction, the extension direction of the third connecting grid line is different from the extension direction of the fourth connecting grid line; and the first and third connecting grid lines are different in shape. The back contact cell provided by the application can distinguish the polarity of the first and second edge main grids.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a back contact cell, a cell module and a photovoltaic system. BACKGROUND

[0002] At present, a solar cell includes a positive main grid and a negative main grid. After the grid lines are printed, the polarity of the grid lines needs to be distinguished. However, the positive main grid and the negative main grid are difficult to distinguish, which leads to the fact that whether the positive main grid and the negative main grid are printed reversely on the silicon substrate cannot be confirmed. Based on this, how to distinguish the positive main grid and the negative main grid of the solar cell has become a technical problem to be solved urgently. SUMMARY

[0003] The present application provides a back contact cell, a cell module and a photovoltaic system, and aims to solve the technical problem that the positive main grid and the negative main grid of the solar cell are difficult to distinguish in the prior art.

[0004] The present application provides a back contact cell, which includes a silicon substrate, a first edge main grid and a second edge main grid, the first edge main grid and the second edge main grid are different in polarity.

[0005] The silicon substrate has opposite first and second edges in a first direction, the first edge main grid is a main grid closest to the first edge, and the second edge main grid is a main grid closest to the second edge.

[0006] The first edge main grid includes a first connecting grid line and a second connecting grid line connected to each other, the second connecting grid line extends along a second direction, the extension direction of the first connecting grid line is different from the second direction, and the second direction intersects the first direction.

[0007] The second edge main grid includes a third connecting grid line and a fourth connecting grid line connected to each other, the fourth connecting grid line extends along the second direction, and the extension direction of the third connecting grid line is different from the extension direction of the fourth connecting grid line.

[0008] The first connecting grid line and the third connecting grid line are different in shape.

[0009] In some embodiments, the first connecting grid line includes a first grid line segment, the first grid line segment is a grid line segment extending along a third direction, and the third direction is different from the extension direction of the first connecting grid line.

[0010] In some embodiments, the third connecting grid line includes a second grid line segment, the second grid line segment is a grid line segment extending along a fourth direction, and the fourth direction is the same as the extension direction of the third connecting grid line.

[0011] In some embodiments, the first connecting gate line has a first end and a second end in an extension direction of the first connecting gate line;

[0012] The first end of the first connecting gate line is connected with an end of the second connecting gate line, and the first gate line segment is located at the second end of the first connecting gate line.

[0013] In some embodiments, the third connecting gate line has a first end and a second end in an extension direction of the third connecting gate line;

[0014] The first end of the third connecting gate line is connected with an end of the fourth connecting gate line, and the second gate line segment is located at the second end of the third connecting gate line.

[0015] In some embodiments, the silicon substrate further comprises a first chamfer connected with an end of the first edge;

[0016] The distance between the first connecting gate line and the first chamfer is less than the distance between the second connecting gate line and the first chamfer.

[0017] In some embodiments, the silicon substrate further comprises a second chamfer connected with an end of the second edge;

[0018] The distance between the third connecting gate line and the second chamfer is less than the distance between the fourth connecting gate line and the second chamfer.

[0019] In some embodiments, the distance between the first connecting gate line and the first chamfer is 500-800 μm.

[0020] In some embodiments, the distance between the second connecting gate line and the first edge is 250-500 μm.

[0021] In some embodiments, the distance between the third connecting gate line and the second chamfer is 500-800 μm.

[0022] In some embodiments, the distance between the fourth connecting gate line and the second edge is 250-500 μm.

[0023] In some embodiments, the silicon substrate has a third edge in the second direction;

[0024] In an end of the first edge main gate in the second direction, the distance from one end close to the third edge to the third edge is a first distance;

[0025] In an end of the second edge main gate in the second direction, the distance from one end close to the third edge to the third edge is a second distance;

[0026] The first distance is greater than the second distance.

[0027] In some embodiments, the silicon substrate further comprises a first internal main grid and a second internal main grid with different polarities; the first internal main grid and the second internal main grid are both located between the first edge main grid and the second edge main grid;

[0028] The first internal main grid has a third distance from the third edge in the second direction, and the second internal main grid has a fourth distance from the third edge in the second direction;

[0029] The third distance is greater than the fourth distance.

[0030] The application also provides a battery assembly comprising the back contact battery.

[0031] The application also provides a photovoltaic system comprising the battery assembly.

[0032] The back contact battery, the battery assembly and the photovoltaic system provided by the embodiments of the application can distinguish the polarities of the first edge main grid and the second edge main grid through the shapes of the first connecting grid line and the second connecting grid line, can confirm whether the printing error occurs in time after the grid line printing is completed, and can distinguish the polarities of the first edge main grid and the second edge main grid when the assembly is welded, thereby reducing the probability of errors in the assembly welding and improving the product yield.

[0033] Additional aspects and advantages of the application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural schematic diagram of the back contact battery provided by the embodiments of the application;

[0035] Figure 2 is a structural schematic diagram of the battery assembly provided by the embodiments of the application;

[0036] Figure 3 is a structural schematic diagram of the photovoltaic system provided by the embodiments of the application. DETAILED DESCRIPTION

[0037] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. The examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are for the purpose of explanation only and are not to be understood as limiting the present application. In addition, it should be understood that the specific embodiments described herein merely serve to explain the present application and are not intended to limit the present application.

[0038] In the description of the present application, it should be understood that the terms "upper", "lower", "back", "front", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0039] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature "below", "below" and "below" of the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0040] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0041] Figure 1 is a structural schematic diagram of a back contact battery provided by an embodiment of the present application. As shown in Figure 1 The present application provides a back contact battery, comprising: a silicon substrate 10, a first edge main grid 20 and a second edge main grid 30, the first edge main grid 20 and the second edge main grid 30 being different in polarity;

[0042] The silicon substrate 10 has opposite first and second edges 101 and 102 in a first direction, the first edge main grid 20 is the main grid closest to the first edge 101, and the second edge main grid 30 is the main grid closest to the second edge 102;

[0043] The first edge main grid 20 includes first and second connection grid lines 201 and 202 connected to each other, the second connection grid line 202 extends along a second direction, and the first connection grid line 201 extends along a direction different from the second direction, and the second direction intersects the first direction;

[0044] The second edge main grid 30 includes third and fourth connection grid lines 301 and 302 connected to each other, the fourth connection grid line 302 extends along the second direction, and the third connection grid line 301 extends along a direction different from the fourth connection grid line 302;

[0045] The first and third connection grid lines 201 and 301 have different shapes.

[0046] In the embodiments of the present application, the back contact cell can be a main grid back contact cell. The back contact cell includes a silicon substrate 10. The silicon substrate 10 can be a whole cell piece, or a half piece, one-third piece, or other proportion of cell piece divided from the whole cell piece. It should be noted that the drawings provided by the present application are schematic drawings, and do not limit the specific form of the back contact cell.

[0047] Further, the silicon substrate 10 can include opposite front and back surfaces, the front surface faces the sun and mainly receives direct sunlight, and the back surface faces the mounting surface of the photovoltaic module and mainly receives sunlight reflected by the mounting surface, for example, the ground or the roof, etc.

[0048] The plurality of fine grids and the plurality of main grids are arranged on the back surface of the silicon substrate 10, and the back surface of the silicon substrate 10 further has a doped layer and a passivation layer arranged in a stack, and the doped layer can be connected with the plurality of fine grids to establish ohmic contact. The fine grid is mainly used to collect the current generated by the back contact cell. When sunlight shines on the back contact cell, photons are absorbed and electrons are excited, which are captured by the fine grid and transmitted. The main grid is responsible for collecting the current on the fine grid and transmitting it to the output end of the cell.

[0049] The plurality of main grids extend along the second direction and are arranged at intervals along the first direction, and the plurality of fine grids extend along the first direction and are arranged at intervals along the second direction. The first direction can be the horizontal direction in Figure 1 , and the second direction can be the vertical direction in Figure 1 . Of course, in other embodiments, the first and second directions can also be other directions, for example, diagonal directions, etc., which are not specifically limited here.

[0050] The silicon substrate 10 has opposite first and second edges 101 and 102 in a first direction. Among a plurality of main grates arranged at intervals along the first direction, a first edge main grate 20 is a main grate closest to the first edge 101, and a second edge main grate 30 is a main grate closest to the second edge 102.

[0051] The first edge main grate 20 includes a first connection grate line 201 and a second connection grate line 202 connected with the first connection grate line 201.

[0052] The connection manner of the first connection grate line 201 and the second connection grate line 202 can include any one of the following: an end of the first connection grate line 201 and an end of the second connection grate line 202 are connected; an end of the first connection grate line 201 and any point on the second connection grate line 202 are connected; any point on the first connection grate line 201 and an end of the second connection grate line 202 are connected.

[0053] It should be noted that the end of the first connection grate line 201 refers to any one of the two ends of the first connection grate line 201 in the extension direction of the first connection grate line 201; and the end on the second connection grate line 202 refers to any one of the two ends of the second connection grate line 202 in the extension direction of the second connection grate line 202.

[0054] The second connection grate line 202 extends along a second direction, and optionally, the second connection grate line 202 is arranged parallel to the first edge 101. The extension direction of the first connection grate line 201 intersects the second direction.

[0055] The second edge main grate 30 includes a third connection grate line 301 and a fourth connection grate line 302 connected with the third connection grate line 301.

[0056] The connection manner of the third connection grate line 301 and the fourth connection grate line 302 can include any one of the following: an end of the third connection grate line 301 and an end of the fourth connection grate line 302 are connected; an end of the third connection grate line 301 and any point on the fourth connection grate line 302 are connected; any point on the third connection grate line 301 and an end of the fourth connection grate line 302 are connected.

[0057] It should be noted that the end of the third connection grate line 301 refers to any one of the two ends of the third connection grate line 301 in the extension direction of the third connection grate line 301; and the end on the fourth connection grate line 302 refers to any one of the two ends of the fourth connection grate line 302 in the extension direction of the fourth connection grate line 302.

[0058] The fourth connection grate line 302 extends along the second direction, and optionally, the fourth connection grate line 302 is arranged parallel to the second edge 102. The extension direction of the third connection grate line 301 intersects the second direction.

[0059] In the embodiments of the present application, different polarities are marked by setting different shapes for the first connecting gate line 201 and the third connecting gate line 301 respectively. The different shapes can be different shapes, different thicknesses, different lengths, different extension directions or different extension angles of the gate lines.

[0060] For example, the third connecting gate line 301 is in a curved or zigzag shape, and it can be determined that the second edge main gate 30 is a positive main gate; the first connecting gate line 201 is in a straight line shape, and it can be determined that the first edge main gate 20 is a negative main gate.

[0061] The third connecting gate line 301 is in a circular shape, and it can be determined that the second edge main gate 30 is a positive main gate; the first connecting gate line 201 is in a triangular shape, and it can be determined that the first edge main gate 20 is a negative main gate.

[0062] The third connecting gate line 301 is in a Y-shaped, and it can be determined that the second edge main gate 30 is a positive main gate; the first connecting gate line 201 is in a parabolic shape, and it can be determined that the first edge main gate 20 is a negative main gate.

[0063] The line width of the third connecting gate line 301 is twice that of the first connecting gate line 201, and it can be determined that the second edge main gate 30 is a positive main gate and the first edge main gate 20 is a negative main gate.

[0064] The length of the third connecting gate line 301 is longer than that of the first connecting gate line 201, and it can be determined that the second edge main gate 30 is a positive main gate and the first edge main gate 20 is a negative main gate.

[0065] It should be noted that the above shapes and polarities can have a one-to-one correspondence relationship, and in the case that the shape of any one of the first connecting gate line 20 or the third connecting gate line 301 is not easy to distinguish, the polarity of the corresponding edge main gate can be determined by the shape of the other gate line. Since the polarities of the first edge main gate 20 and the second edge main gate 30 are opposite, as long as the polarity of one edge main gate is determined, the polarity of the other edge main gate can also be determined accordingly.

[0066] The back contact battery provided in the embodiments of the present application can distinguish the polarities of the first edge main gate and the second edge main gate by setting different shapes for the first connecting gate line and the second connecting gate line, can confirm whether the printing is reversed in time after the printing of the gate lines is completed, and can distinguish the polarities of the first edge main gate and the second edge main gate when the assembly is welded, thereby reducing the probability of errors in the assembly welding and improving the product yield.

[0067] In some embodiments, the first connection gate line 201 comprises a first gate line segment 2001, which is a gate line segment extending in a third direction different from the extension direction of the first connection gate line 201.

[0068] In actual implementation, the first connection gate line 201 comprises a first gate line segment 2001 for marking polarity and extending in a third direction. The first gate line segment 2001 is located in the first connection gate line 201, and the third direction is different from the extension direction of the first connection gate line 201. The third direction can be the same as or different from the second direction.

[0069] The extension direction different refers to that the included angle or curvature of the first gate line segment relative to the first connection gate line 201 is different.

[0070] Optionally, the first gate line segment 2001 can be located at the end in the extension direction of the first connection gate line 201, or between the two ends of the first connection gate line 201, which is not specifically limited here.

[0071] The back contact battery provided by the embodiments of the present application facilitates the identification of the polarity of the main gate by arranging the first gate line segment for polarity distinction on the first connection gate line, improves the identifiable of the polarity of the first edge main gate, and the extension direction of the first gate line segment is different from that of the first connection gate line, so that the polarity of the main gate can be determined more intuitively, and effective information for distinguishing the polarity can be obtained quickly.

[0072] In some embodiments, the third connection gate line 301 comprises a second gate line segment; the second gate line segment is a gate line segment extending in a fourth direction, and the fourth direction is the same as the extension direction of the third connection gate line 301.

[0073] In actual implementation, the third connection gate line 301 comprises a second gate line segment for marking polarity and extending in a fourth direction. The second gate line segment is located in the third connection gate line 301, and the fourth direction is the same as the extension direction of the third connection gate line 301, and the fourth direction is different from the second direction.

[0074] The extension direction same refers to that the included angle of the second gate line segment relative to the third connection gate line 301 is 0 degrees or the curvature is the same.

[0075] Optionally, the second gate line segment can be located at the end in the extension direction of the third connection gate line 301, or between the two ends of the third connection gate line 301, which is not specifically limited here.

[0076] The back contact battery provided in the embodiment of the present application is convenient for distinguishing the polarity of the main grid by setting the second grid line segment for polarity distinction on the third connection grid line, improves the distinguishability of the polarity of the second edge main grid, and can also reduce the risk of the main grid polarity being indistinguishable in the case that the shape of the first grid line segment cannot be distinguished.

[0077] In some embodiments, the first connection grid line 201 has a first end and a second end in the extension direction of the first connection grid line 201;

[0078] The first end of the first connection grid line 201 is connected with the end of the second connection grid line 202, and the first grid line segment 2001 is located at the second end of the first connection grid line 201.

[0079] In actual implementation, the first end of the first connection grid line 201 is connected with the end of the second connection grid line 202 in the second direction in the extension direction of the first connection grid line 201. The second end of the first connection grid line 201 is provided with the first grid line segment 2001 extending in the third direction, so that it can be seen that the first connection grid line 201 is curved or bent at the end.

[0080] The back contact battery provided in the embodiment of the present application is convenient for distinguishing the polarity of the main grid by setting the second grid line segment for polarity distinction on the third connection grid line, improves the distinguishability of the polarity of the second edge main grid, and can also reduce the risk of the main grid polarity being indistinguishable in the case that the shape of the first grid line segment cannot be distinguished.

[0081] In some embodiments, the third connection grid line 301 has a first end and a second end in the extension direction of the third connection grid line 301;

[0082] The first end of the third connection grid line 301 is connected with the end of the fourth connection grid line 302, and the second grid line segment is located at the second end of the third connection grid line 301.

[0083] In actual implementation, the first end of the third connection grid line 301 is connected with the end of the fourth connection grid line 302 in the second direction in the extension direction of the third connection grid line 301. The second end of the third connection grid line 301 is provided with the second grid line segment extending in the fourth direction, so that it can be seen that the third connection grid line 301 is not curved or bent at the end, but presents a straight line shape.

[0084] The back contact battery provided in the embodiment of the present application is convenient for distinguishing the polarity of the main grid by setting the second grid line segment for polarity distinction on the third connection grid line, improves the distinguishability of the polarity of the second edge main grid, and can also reduce the risk of the main grid polarity being indistinguishable in the case that the shape of the first grid line segment cannot be distinguished.

[0085] In some embodiments, the silicon substrate 10 further includes a first chamfer 103 connected with the end of the first edge 101;

[0086] The distance between the first connecting grid line 201 and the first chamfer 103 is greater than the distance between the second connecting grid line 202 and the first chamfer 103.

[0087] In actual implementation, the first edge 101 in the silicon substrate 10 is provided with a first chamfer 103 at the joint with its adjacent edge. The first connecting grid line 201 is connected with the end of the second connecting grid line 202, and the second connecting grid line 202 extends in the second direction, and the extending directions of the first connecting grid line 201 and the second connecting grid line 202 are different.

[0088] The distance between the first connecting grid line 201 and the first chamfer 103 refers to the distance between any point on the first connecting grid line 201 and any point on the first chamfer 103, and the distance between the second connecting grid line 202 and the first chamfer 103 refers to the distance between any point on the second connecting grid line 202 and any point on the first chamfer 103.

[0089] The second connecting grid line 202 extends close to the first edge 101, and the first connecting grid line 201 extends close to the first chamfer 103, so the distance between the first connecting grid line 201 and the first chamfer 103 is less than the distance between the second connecting grid line 202 and the first chamfer 103, and thus the distance between the first connecting grid line 201 and the first edge 101 is greater than the distance between the second connecting grid line 202 and the first edge 101.

[0090] It can be understood that there is more space at the first chamfer, and thus the first grid segment of the first connecting grid line 201 can be kept at a sufficient distance from the first chamfer.

[0091] The back contact battery provided by the embodiment of the present application can provide a sufficient distance for the setting position of the first grid segment by setting the first connecting grid line at a position closer to the first chamfer relative to the distance between the second connecting grid line and the first chamfer, so as to ensure the reliability of the battery.

[0092] In some embodiments, the silicon substrate 10 further comprises a second chamfer 104 connected with the end of the second edge 102;

[0093] The distance between the third connecting grid line 301 and the second chamfer 104 is greater than the distance between the fourth connecting grid line 302 and the second chamfer 104.

[0094] In actual implementation, the second edge 102 in the silicon substrate 10 is provided with a second chamfer 104 at the joint with its adjacent edge. The third connecting grid line 301 is connected with the end of the fourth connecting grid line 302, and the fourth connecting grid line 302 extends in the second direction, and the extending directions of the third connecting grid line 301 and the fourth connecting grid line 302 are the same.

[0095] The distance between the third connecting grid line 301 and the second chamfer 104 refers to the distance between any point on the third connecting grid line 301 and any point on the second chamfer 104, and the distance between the fourth connecting grid line 302 and the second chamfer 104 refers to the distance between any point on the fourth connecting grid line 302 and any point on the second chamfer 104.

[0096] The fourth connecting grid line 302 extends close to the second edge 102, and the third connecting grid line 301 extends close to the second chamfer 104, so the distance between the third connecting grid line 301 and the second chamfer 104 is smaller than the distance between the second connecting grid line 202 and the second chamfer 104, and thus the distance between the third connecting grid line 301 and the second edge 102 is greater than the distance between the second connecting grid line 202 and the second edge 102.

[0097] The back contact battery provided by the embodiment of the present application can provide sufficient space for the setting position of the second grid segment by setting the third connecting grid line at a position closer to the second chamfer relative to the distance between the fourth connecting grid line and the second chamfer, so that the battery reliability can be ensured.

[0098] Optionally, the distance between the first connecting grid line 201 and the first chamfer 103 is 500-800 μm.

[0099] In actual implementation, the distance between the first connecting grid line 201 and the first chamfer 103 may, for example, be 500 μm, 600 μm, 700 μm or 800 μm, or be a range value of 500-800 μm, which is not specifically limited herein.

[0100] The back contact battery provided by the embodiment of the present application can provide space for the setting of the first grid segment by setting the distance between the first connecting grid line and the first chamfer to be 500-800 μm, while ensuring that the battery reliability is not affected.

[0101] Optionally, the distance between the second connecting grid line 202 and the first edge 101 is 250-500 μm.

[0102] In actual implementation, the distance between the second connecting grid line 202 and the first edge 101 may, for example, be 250 μm, 275 μm, 300 μm, 400 μm, 465 μm or 500 μm, or be a range value of 250-500 μm, which is not specifically limited herein.

[0103] The back contact battery provided by the embodiment of the present application can ensure that the second connecting grid line maintains a safe distance from the first edge by setting the distance between the second connecting grid line and the first edge to be 250-500 μm, thereby improving the battery reliability.

[0104] Optionally, the distance between the third connection gate line 301 and the second chamfer 104 is 500-800 μm.

[0105] In actual implementation, the distance between the third connection gate line 301 and the second chamfer 104 may be, for example, 500 μm, 600 μm, 700 μm, or 800 μm, or a range value of 500-800 μm, which is not specifically limited herein.

[0106] The back contact battery provided by the embodiment of the present application can provide space for the setting of the second gate line segment by setting the distance between the third connection gate line and the second chamfer to be between 500-800 μm, while ensuring that the battery reliability is not affected.

[0107] Optionally, the distance between the fourth connection gate line 302 and the second edge 102 is 250-500 μm.

[0108] In actual implementation, the distance between the fourth connection gate line 302 and the second edge 102 may be, for example, 250 μm, 275 μm, 300 μm, 400 μm, 465 μm, or 500 μm, or a range value of 250-500 μm, which is not specifically limited herein.

[0109] The back contact battery provided by the embodiment of the present application can ensure that the fourth connection gate line maintains a safe distance from the first edge by setting the distance between the fourth connection gate line and the second edge to be between 250-500 μm, thereby improving the battery reliability.

[0110] In some embodiments, the silicon substrate 10 has a third edge 105 in the second direction;

[0111] In the end of the first edge main gate 20 in the second direction, the distance from one end close to the third edge 105 to the third edge 105 is a first distance;

[0112] In the end of the second edge main gate 30 in the second direction, the distance from one end close to the third edge 105 to the third edge 105 is a second distance;

[0113] The first distance is greater than the second distance.

[0114] It can be understood that the first edge main gate 20 and the second edge main gate 30 can also be distinguished by the distance from the edge. For example, if the first distance from one end of the first edge main gate 20 close to the third edge 105 to the third edge 105 is greater than the second distance from one end of the second edge main gate 30 close to the third edge 105 to the third edge 105, the first edge main gate 20 is a negative main gate, and the second edge main gate 30 is a positive main gate.

[0115] The back contact battery provided in the embodiments of the present application can identify the polarity of the edge main grid by comparing the distances from one end of the first edge main grid and one end of the second edge main grid to the third edge, and further improve the distinctness and easy identification of the polarity of the edge main grid.

[0116] In some embodiments, the silicon substrate 10 further comprises a first internal main grid 40 and a second internal main grid 50 with different polarities; the first internal main grid 40 and the second internal main grid 50 are both located between the first edge main grid 20 and the second edge main grid 30.

[0117] The distance from one end of the first internal main grid 40 close to the third edge 105 to the third edge 105 in the second direction is a third distance, and the distance from one end of the second internal main grid 50 close to the third edge 105 to the third edge 105 in the second direction is a fourth distance.

[0118] The third distance is greater than the fourth distance.

[0119] It can be understood that the first internal main grid 40 and the second internal main grid 50 are alternately and spacedly arranged along the first direction, and the polarities of the first internal main grid 40 and the second internal main grid 50 can also be distinguished by the distance from the edge.

[0120] For example, if the third distance from one end of the first internal main grid 40 close to the third edge 105 to the third edge 105 is greater than the fourth distance from one end of the second internal main grid 50 close to the third edge 105 to the third edge 105, the first internal main grid 40 is a negative main grid, and the second internal main grid 50 is a positive main grid.

[0121] Therefore, in the embodiments of the present application, the polarity of the first internal main grid 40 is the same as that of the first edge main grid 20, and the polarity of the second internal main grid 50 is the same as that of the second edge main grid 30.

[0122] The back contact battery provided in the embodiments of the present application can identify the polarity of the internal main grid by comparing the distances from one end of the first internal main grid and one end of the second internal main grid to the third edge, and further improve the distinctness and easy identification of the polarity of the internal main grid.

[0123] Figure 2 is a structural schematic diagram of a battery assembly provided in the embodiments of the present application. As shown in Figure 2 The battery assembly 200 in the embodiments of the present application comprises the back contact battery 100 in any of the above embodiments.

[0124] The battery assembly of the embodiment of the present application can distinguish the polarity of the first edge main grid and the second edge main grid through the shape by setting the first connection grid line and the second connection grid line to different shapes, can confirm whether the reverse printing problem occurs in time after the grid line printing is completed, can distinguish the polarity of the first edge main grid and the second edge main grid when the assembly is welded, reduces the probability of error in the assembly welding, and thus improves the product yield.

[0125] In the embodiment, the plurality of solar cells in the battery assembly 200 can be sequentially connected in series to form a cell string, so that the series connection of the current is realized. For example, the connection of the solar cell pieces can be realized by setting a welding strip (bus bar, interconnection strip), a conductive back plate and the like.

[0126] It can be understood that in such an embodiment, the battery assembly 200 can further include a metal frame, a back plate, photovoltaic glass and a glue film. The glue film can be filled between the front and back surfaces of the solar cell and the photovoltaic glass, the adjacent solar cell pieces and the like, and can be a transparent glue with good light transmission performance and aging resistance, for example, the glue film can be EVA glue film or POE glue film, which can be selected according to actual conditions, and is not limited herein.

[0127] The photovoltaic glass can be covered on the glue film on the front surface of the solar cell. The photovoltaic glass can be super white glass, which has high light transmittance, high transparency and superior physical, mechanical and optical properties. For example, the light transmittance of the super white glass can be more than 92%, which can protect the solar cell as much as possible without affecting the efficiency of the solar cell. At the same time, the glue film can bond the photovoltaic glass and the solar cell together, and the existence of the glue film can seal and insulate the solar cell and prevent water and moisture.

[0128] The back plate can be attached to the glue film on the back surface of the solar cell. The back plate can protect and support the solar cell, has reliable insulation, water resistance and aging resistance, and can have multiple choices, which can be tempered glass, organic glass, aluminum alloy TPT composite glue film and the like, which can be set according to actual conditions, and is not limited herein. The whole composed of the back plate, the solar cell, the glue film and the photovoltaic glass can be arranged on the metal frame. The metal frame serves as the main external support structure of the whole battery assembly 200, and can stably support and install the battery assembly 200. For example, the battery assembly 200 can be installed at the position required to be installed through the metal frame.

[0129] Figure 3 is a structural schematic diagram of a photovoltaic system provided by the embodiment of the present application. As shown in Figure 3 The photovoltaic system 300 of the embodiment of the present application includes the battery assembly 200 in the above embodiment.

[0130] The photovoltaic system of the embodiment of the present application can distinguish the polarity of the first edge main grid and the second edge main grid through the shape, can confirm whether the printing error occurs in time after the grid line printing is completed, and can distinguish the polarity of the first edge main grid and the second edge main grid when the assembly is welded, thereby reducing the probability of welding error of the assembly, and improving the product yield.

[0131] In the embodiment, the photovoltaic system 300 can be applied in a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station, etc., and can also be applied in a device or apparatus using solar energy to generate electricity, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it can be understood that the application scenarios of the photovoltaic system 300 are not limited to this, that is, the photovoltaic system 300 can be applied in all fields requiring solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system 300 can include a photovoltaic array, a combiner box and an inverter, the photovoltaic array can be an array combination of a plurality of cell assemblies, for example, a plurality of cell assemblies can form a plurality of photovoltaic arrays, the photovoltaic arrays are connected to the combiner box, the combiner box can combine the current generated by the photovoltaic arrays, the combined current flows through the inverter to convert into alternating current required by the power grid, and then is connected to the power network to realize solar power supply.

[0132] In the description of the present specification, the description referring to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0133] In addition, the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A back-contact battery, characterized in that, include: A silicon substrate, a first edge main gate, and a second edge main gate, wherein the first edge main gate and the second edge main gate have different characteristics; The silicon substrate has a first edge and a second edge opposite each other in a first direction, the first edge main gate is the main gate closest to the first edge, and the second edge main gate is the main gate closest to the second edge; The first edge main grid includes a first connecting grid line and a second connecting grid line that are connected to each other. The second connecting grid line extends along a second direction. The extension direction of the first connecting grid line is different from the second direction. The second direction intersects the first direction. The second edge main gate includes a third connecting gate line and a fourth connecting gate line that are connected to each other. The fourth connecting gate line extends along a second direction, and the extension directions of the third connecting gate line and the fourth connecting gate line are different. The first connecting gate line and the third connecting gate line have different shapes.

2. The back contact battery according to claim 1, characterized in that, The first edge main gate includes a first gate line segment, which is a gate line segment extending along a third direction, and the third direction is different from the extension direction of the first connecting gate line.

3. The back contact battery according to claim 1, characterized in that, The second edge main gate includes a second gate line segment; the second gate line segment is a gate line segment extending in a fourth direction, the fourth direction being the same as the extending direction of the third connecting gate line.

4. The back contact battery according to claim 2, characterized in that, In the extending direction of the first connecting gate line, the first connecting gate line has a first end and a second end; The first end of the first connecting gate line is connected to the end of the second connecting gate line, and the first gate line segment is located at the second end of the first connecting gate line.

5. The back contact battery according to claim 3, characterized in that, In the extending direction of the third connecting gate line, the third connecting gate line has a first end and a second end; The first end of the third connecting gate line is connected to the end of the fourth connecting gate line, and the second gate line segment is located at the second end of the third connecting gate line.

6. The back contact battery according to claim 1, characterized in that, The silicon substrate further includes a first chamfer, which is connected to the end of the first edge; The distance between the first connecting gate line and the first chamfer is less than the distance between the second connecting gate line and the first chamfer.

7. The back contact battery according to claim 1, characterized in that, The silicon substrate further includes a second chamfer, which is connected to the end of the second edge; The distance between the third connecting grid line and the second chamfer is less than the distance between the fourth connecting grid line and the second chamfer.

8. The back contact battery according to claim 6, characterized in that, The distance between the first connecting grid line and the first chamfer is 500μm~800μm.

9. The back contact battery according to claim 8, characterized in that, The distance between the second connecting gate line and the first edge is 250μm~500μm.

10. The back contact battery according to claim 7, characterized in that, The distance between the third connecting grid line and the second chamfer is 500μm~800μm.

11. The back contact battery according to claim 9, characterized in that, The distance between the fourth connecting gate line and the second edge is 250μm~500μm.

12. The back contact battery according to claim 1, characterized in that, The silicon substrate has a third edge in the second direction; In the first edge main gate, the distance from the end closest to the third edge to the third edge in the second direction is the first distance; In the second edge main gate, at one end in the second direction, the distance from the third edge to the end closest to the third edge is the second distance; The first distance is greater than the second distance.

13. The back contact battery according to claim 1, characterized in that, The silicon substrate further includes a first internal main gate and a second internal main gate with different polarities; the first internal main gate and the second internal main gate are both located between the first edge main gate and the second edge main gate; The distance from the end of the first internal main gate near the third edge in the second direction to the third edge is the third distance, and the distance from the end of the second internal main gate near the third edge in the second direction to the third edge is the fourth distance; The third distance is greater than the fourth distance.

14. A battery assembly, characterized in that, include: The back contact battery according to any one of claims 1-13.

15. A photovoltaic system, characterized in that, include: The battery assembly as described in claim 14.

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