A back-contact battery, a back-contact tandem battery, and a photovoltaic module

Abstract

This application relates to the field of photovoltaic cell technology, and more particularly to a back-contact cell, a back-contact tandem cell, and a photovoltaic module. The back-contact cell includes a body, a fine grid, a first pad, a first connecting line, and edge grid lines. The fine grid includes a first fine grid and a second fine grid. The first connecting line and the first fine grid are electrically connected to the first pad, and the second fine grid is insulated from the first pad. The second fine grid includes a first grid line and a plurality of second grid lines arranged along a second direction. The first grid line and the first connecting line are arranged along the second direction, and the second grid lines and the first connecting line are arranged along a first direction. In the first direction, the fine grid is located on one side of the edge grid lines. Both the first and second grid lines are electrically connected to the edge grid lines, improving the brightness uniformity of EL testing and the output power of the back-contact cell. Furthermore, in the first direction, the length of the first grid line is not less than the sum of the lengths of the plurality of second grid lines to improve the current transmission capability of the first grid line, thereby increasing the output power of the back-contact cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, and in particular to a back-contact cell, a back-contact tandem cell, and a photovoltaic module. Background Technology

[0002] The back contact battery includes a fine grid and pads disposed on the back surface. The pads are electrically connected to the grid lines and are used to weld and fix the battery to the solder strip to achieve current collection.

[0003] When the electrical connection between some grid lines and pads is broken, the brightness of the back contact battery is uneven and the color is dark in some areas during EL testing. The photoelectric conversion efficiency of the darker areas is low or even zero, resulting in a lower output power of the back contact battery.

[0004] Therefore, improving the brightness uniformity of EL testing to increase output power is an important problem that needs to be solved in this field. Summary of the Invention

[0005] In view of this, this application provides a back-contact battery, a back-contact tandem battery, and a photovoltaic module, which can improve the brightness uniformity and output power of EL testing.

[0006] This application provides a back contact battery, including a body, a fine grid, a first pad, a first connecting line, and an edge grid line. The fine grid includes a first fine grid and a second fine grid arranged alternately along a second direction. The first pad is electrically connected to the first fine grid and insulated from the second fine grid. The first connecting line is electrically connected to the first pad. The second fine grid includes a first grid line and a plurality of second grid lines. Both the first grid line and the second grid line are insulated from the first connecting line. The first grid line and the first connecting line are arranged along the second direction, and the second grid lines and the first connecting line are arranged along a first direction. In the first direction, the fine grid is located on one side of the edge grid line. Both the first grid line and the second grid line are electrically connected to the edge grid line. In the first direction, the length of the first grid line is L1, and the sum of the lengths of the plurality of second grid lines is L2, where L2 ≤ L1.

[0007] In this application, the second grid line is disconnected at the first connection line, which reduces the risk of short circuit of the back contact battery caused by the second fine grid contacting the first connection line in the first direction, and improves the performance of the back contact battery.

[0008] The second grid line is electrically connected to the unbroken first grid line through the edge grid line, so that the current on the broken second grid line can be transmitted to the solder ribbon through the edge grid line and the first grid line. This reduces the risk of uneven brightness and local dark color when the back contact battery is tested by EL, improves the brightness uniformity of EL test, reduces the risk of reduced output power of the back contact battery due to the inability to collect current on the broken second grid line, and improves the output power of the back contact battery.

[0009] L2≤L1, meaning the length of the first grid line is not less than the total length of the second grid line electrically connected to it, in order to improve the current transmission capability of the first grid line, so as to improve the output power of the back contact battery.

[0010] In some possible designs, multiple first pads are arranged in a second direction, including a first edge pad located on the outermost side in the second direction, and a first connection line including a main connection line electrically connected to the first edge pad.

[0011] In some possible designs, the first pad also includes a central pad, which is located on one side of the first edge pad in a second direction. In the second direction, at least one central pad is disposed between the first edge pad and the first gate line.

[0012] In some possible designs, the first pad also includes a central pad, which is located on one side of the first edge pad in the second direction. The central pad includes at least a first central pad, a second central pad, and a third central pad arranged along the second direction. The first connection line also includes a secondary connection line, which includes at least a first segment and a second segment. The two ends of the first segment are electrically connected to the first central pad and the second central pad, respectively, and the two ends of the second segment are electrically connected to the second central pad and the third central pad, respectively. A portion of the second gate line is arranged along the first direction with the first segment, and a portion of the second gate line is arranged along the first direction with the second segment.

[0013] In some possible designs, the width of the primary connector is greater than the width of the secondary connector in the first direction.

[0014] In some possible designs, multiple first gate lines are spaced apart along the second direction, and multiple central pads are provided between two adjacent first gate lines.

[0015] In some possible designs, the edge gate lines include a first edge gate line and a second edge gate line. The first edge gate line and a first edge pad are distributed along a first direction, and the second edge gate line and a central pad are distributed along the first direction. The first and second edge gate lines are also distributed along a second direction. In the first direction, the width of the first edge gate line is greater than the width of the second edge gate line.

[0016] In some possible designs, the first edge gate line is electrically connected to the second edge gate line.

[0017] In some possible designs, 1≤L1 / L2≤1.5.

[0018] In some possible designs, the back contact battery also includes a second pad, which, in a first direction, is located on the side of the first pad away from the edge grid line. The second grid also includes a third grid line, in the first direction, with a portion of the second pad connected to both the first and third grid lines on its sides, respectively. In the second direction, the width of the first grid line is greater than the width of the third grid line.

[0019] In some possible designs, the width of the edge gate line is H1, and the width of the second fine gate electrically connected to the edge gate line is H2, where H2 < H1.

[0020] In some possible designs, the back contact battery also includes a second pad located on the side of the first pad away from the edge grid line in a first direction. The second pad is electrically connected to a second fine grid and insulated from the first fine grid. Multiple second pads are arranged along a second direction, including a second edge pad located on the outermost side in the second direction. The back contact battery also includes a second connecting line electrically connected to the second edge pad. A portion of the second fine grid is electrically connected to the second edge pad, and a portion of the second fine grid is electrically connected to the second connecting line.

[0021] In some possible designs, the back contact battery also includes a second pad located on the side of the first pad away from the edge grid line in a first direction. The second pad is electrically connected to a second fine grid and insulated from the first fine grid. A plurality of second pads are arranged along a second direction. The back contact battery also includes a third connecting line, with its two ends electrically connected to adjacent second pads in the second direction.

[0022] A second aspect of this application provides a back-contact stacked solar cell, including a back-contact bottom cell and a perovskite top cell, wherein the back-contact bottom cell is any of the back-contact cells described above, and the perovskite top cell and the back-contact bottom cell are electrically connected to each other on their light-facing surfaces.

[0023] A third aspect of this application provides a photovoltaic module, including a cover plate, an encapsulation layer, and a cell layer, wherein the cell layer includes a plurality of back-contact cells as described in any one of the above-described embodiments, and / or, the cell layer includes a plurality of back-contact stacked cells as described above.

[0024] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments 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.

[0026] Figure 1 A schematic diagram of the structure of the back contact battery provided in this application in some embodiments;

[0027] Figure 2 Schematic diagrams of the back contact battery provided in this application in other embodiments;

[0028] Figure 3 A schematic diagram of the structure of the back contact battery provided in this application in some other embodiments;

[0029] Figure 4 A schematic diagram of the structure of the back contact battery provided in this application in some other embodiments;

[0030] Figure 5 A schematic diagram of the structure of the back contact battery provided in this application in some other embodiments;

[0031] Figure 6 for Figure 5 A partial structural diagram of the back contact battery in some embodiments;

[0032] Figure 7 for Figure 5 A partial structural diagram of the back contact battery in some other embodiments;

[0033] Figure 8 for Figure 5 A partial structural diagram of the back contact battery in some other embodiments;

[0034] Figure 9 for Figure 5 A partial structural diagram of the back contact battery in some other embodiments;

[0035] Figure 10 for Figure 5 A partial structural diagram of the back contact battery in some other embodiments;

[0036] Figure 11 for Figure 5 A partial structural diagram of the back contact battery in some other embodiments;

[0037] Figure 12 for Figure 5 A partial structural diagram of the back contact battery in some other embodiments;

[0038] Figure 13 This is a schematic diagram of the stacked structure of the back contact stacked battery provided in this application in some embodiments;

[0039] Figure 14 Cross-sectional views of the photovoltaic module provided in this application in some embodiments;

[0040] Figure 15 for Figure 14 The diagram shows the connection structure of the battery layer in some embodiments.

[0041] Figure label:

[0042] 10-Cover plate; 101-First cover plate; 102-Second cover plate;

[0043] 20 - Encapsulation layer; 201 - First adhesive film; 202 - Second adhesive film;

[0044] 30-Battery layer; 301-Back contact bottom cell; 302-Perovskite top cell; 303-Back contact stacked cell; 304-Full cell; 305-Divided cell; 306-Three-divided cell; 307-Cell; 308-Welding ribbon; 309-Busbar;

[0045] 1-Body; 2-Fine gate; 21-First fine gate; 22-Second fine gate; 221-First gate line; 222-Second gate line; 223-Third gate line;

[0046] 3-Pad; 31-First pad; 311-First edge pad; 312-Center pad; 312A-First center pad; 312B-Second center pad; 312C-Third center pad; 32-Second pad; 321-Second edge pad; 33-Third pad; 331-Third edge pad;

[0047] 4-First connecting line; 41-Main connecting line; 42-Secondary connecting line; 421-First segment; 422-Second segment;

[0048] 5 - Edge grid line; 51 - First edge grid line; 52 - Second edge grid line;

[0049] 6 - Second connecting line; 7 - Third connecting line; 8 - Fourth connecting line; 9 - Fifth connecting line; X - First direction; Y - Second direction; Z - Third direction. Detailed Implementation

[0050] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0051] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0052] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0053] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0054] The first aspect of this application provides a back contact battery. In some embodiments, the back contact battery cells can be one of the following: interdigitated back contact (IBC), heterojunction back contact (HBC), and tunnel oxide back contact (TBC).

[0055] For an IBC cell, along its thickness direction, the IBC cell sequentially includes a silicon nitride inversion layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer 14, a silicon nitride antireflection layer, and a metallic silver electrode.

[0056] IBC cells utilize ion implantation technology to obtain P- and N-regions with good uniformity and precise controllable junction depth. The absence of grid lines on the front of the cell eliminates light-blocking current loss from metal electrodes, maximizing the utilization of incident photons and improving short-circuit current by approximately 7% compared to conventional solar cells. Due to the back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front-surface recombination rates and surface reflections.

[0057] For HBC cells, the advantages of IBC cells and heterojunction cells are well combined. The passivation layer on the front surface is made of hydrogenated amorphous silicon, and N-type and P-type amorphous silicon thin films are deposited on the back to form a heterojunction.

[0058] HBC cells fully utilize the superior surface passivation properties of amorphous silicon. The heterojunction structure formed on the back has a good passivation effect, which can simultaneously achieve higher short-circuit current and open-circuit voltage, thereby improving photoelectric conversion efficiency.

[0059] For TBC batteries, the combination of Topcon's tunneling oxide layer technology and the advantages of IBC back-side electrode arrangement significantly improves passivation effect and open-circuit voltage, achieving higher battery conversion efficiency while being economical.

[0060] The complete production process of TBC cells mainly includes depositing tunneling oxide and P+ polycrystalline silicon, depositing passivation films, and printing electrodes on the back of the silicon wafer. Based on the TOPCon production process, TBC cells require additional back electrode processes such as masking, laser grooving, PN region fabrication, and etching. Masking is mainly done using APCVD or PECVD, PN region fabrication is mainly done using PECVD, etching mainly uses traditional wet etching equipment, and grooving is performed using laser equipment.

[0061] The embodiments of this application do not specifically limit the type of back contact battery.

[0062] Figure 1 The diagram shows the structure of the back contact battery provided in this application in some embodiments. Figure 1 As shown, in some embodiments, the back contact battery is a single cell 304.

[0063] Figure 2 The diagram shows the structure of the back contact battery provided in this application in some embodiments. Figure 2 As shown, in some other embodiments, the back contact battery is a two-piece battery 305, that is, the entire battery 304 is arranged along... Figure 2 The dotted line in the middle is cut into two halves, and one half is used to make a two-piece battery 305.

[0064] Figure 3 The diagram shows the structure of the back contact battery provided in this application in some embodiments. Figure 3 As shown, in some other embodiments, the battery cell is a three-cell battery 306 or other multi-cell battery. Taking the three-cell battery 306 as an example, the entire battery cell 304 is arranged along... Figure 3 The dotted line in the middle is cut into three pieces, and one of the pieces is used to make a three-piece battery 306.

[0065] The embodiments of this application do not specifically limit the type of back contact battery, that is, the back contact battery can be a whole battery, a two-piece battery, a three-piece battery or other multi-piece battery.

[0066] The back contact battery can be constructed as a gridless battery or as a battery with a grid. In this application, the number of grids in the back contact battery is not specifically limited.

[0067] Figure 4 This is a schematic diagram of the structure of a back contact battery in some embodiments. Figure 4 The example illustrates that the back-contact battery is a single cell.

[0068] Figure 5 This is a schematic diagram of the structure of a back contact battery in some embodiments. Figure 5 The example illustrates a back-contact battery as a two-piece battery.

[0069] The following discussion uses the back-contact battery as an example of a two-piece battery to illustrate the specific structure of the back-contact battery.

[0070] like Figure 5 As shown, the back contact battery includes a body 1, which has a light-facing surface and a back-light surface arranged opposite to each other along its thickness direction. The light-facing surface is the side of the body 1 facing the sunlight when the back contact battery is in operation, and the back-light surface is the side of the body 1 away from the sunlight when the back contact battery is in operation. The light-facing surface can also be understood as the upper surface of the body 1, and the back-light surface can be understood as the lower surface of the body 1.

[0071] like Figure 5 As shown, the back surface of the body 1 is provided with fine grids 2 extending along the first direction X, and a plurality of fine grids 2 are arranged along the second direction Y. Let the thickness direction of the back contact battery be denoted as the third direction Z. Then, both the first direction X and the second direction Y are perpendicular to the third direction Z. For example, one of the first direction X and the second direction Y is the length direction of the back contact battery, and the other is the width direction of the back contact battery.

[0072] like Figure 5 As shown, the fine grid 2 includes a first fine grid 21 and a second fine grid 22 arranged alternately along the second direction Y. One of the first fine grid 21 and the second fine grid 22 is configured as a negative electrode fine grid that is in back contact with the battery, and the other is configured as a positive electrode fine grid that is in back contact with the battery.

[0073] like Figure 5 As shown, the back contact battery also includes a pad 3, which is electrically connected to the fine grid 2. The pad 3 is used to weld and fix the battery to the solder strip, thereby making multiple back contact batteries electrically connected.

[0074] The pad 3 includes a positive pad and a negative pad. The positive pad is used for electrical connection with the positive gate and for soldering and fixing to the positive solder strip. The negative pad is used for electrical connection with the negative gate and for soldering and fixing to the negative solder strip. Multiple positive pads are arranged in a positive soldering array in the second direction Y, and multiple negative pads are arranged in a negative soldering array in the second direction Y. The positive and negative soldering arrays are arranged alternately along the first direction X, such that the positive and negative solder strips are arranged alternately along the first direction X.

[0075] The back contact battery also includes connecting lines disposed on the backlight surface of the body 1. In the second direction Y, both ends of the connecting lines are electrically connected to adjacent pads 3 of the same polarity. Alternatively, in the second direction Y, one end of the connecting line is electrically connected to the pad 3, and the other end extends toward the edge of the body 1, so that the fine grid 2 between the pad 3 and the edge can be electrically connected to the pad 3 of the same polarity through the connecting lines.

[0076] The connecting line can be electrically connected to the first pad 31 or the second pad 32. The structural design of the pad 3, the connecting line and the fine gate 2 will be discussed in detail below, taking the first pad 31 as an example.

[0077] Figure 6 This is a partial structural diagram of a back-contact battery in some embodiments. For example... Figure 6 As shown, the back contact battery includes a first connecting line 4 disposed on the back surface of the body 1. The first connecting line 4 is electrically connected to the first pad 31. That is, the polarity of the first connecting line 4 is the same as that of the first fine grid 21 and the first pad 31, and opposite to that of the second fine grid 22 and the second pad 32. The first connecting line 4 needs to be insulated from the second fine grid 22 and the second pad 32 to reduce the risk of short circuit in the back contact battery and improve the performance of the back contact battery.

[0078] like Figure 6 As shown, the second fine gate 22 includes a first gate line 221 and a plurality of second gate lines 222 arranged along the second direction Y. Both the first gate line 221 and the second gate line 222 are insulated from the first connecting line 4. The first gate line 221 and the first connecting line 4 are arranged along the second direction Y, that is, in the second direction Y, the first pad 31 is located between the first connecting line 4 and the first gate line 221. The second gate line 222 and the first connecting line 4 are arranged along the first direction X, that is, in the first direction X, the second gate line 222 is located on one side or both sides of the first connecting line 4.

[0079] In this embodiment, the second grid line 222 is disconnected at the first connecting line 4, which reduces the risk of the back contact battery short-circuiting due to the second fine grid 22 contacting the first connecting line 4 in the first direction X, thereby improving the performance of the back contact battery.

[0080] In some embodiments, the second grid line 222 is disconnected at the first connection line 4, so that the current on part of the second grid line 222 cannot be collected. When performing EL testing on the back contact battery, the test brightness of the second grid line 222, which cannot collect current, is low, resulting in uneven brightness and local dark color when the back contact battery is tested. The photoelectric conversion efficiency of the dark part is low or even zero, resulting in low output power of the back contact battery.

[0081] Therefore, in the embodiments of this application, as Figure 6As shown, the back contact battery also includes edge grid lines 5. In the first direction X, fine grids 2 are located on one side of edge grid lines 5, and the first fine grid 21 and the second fine grid 22 are located on the same side of edge grid lines 5. The first grid line 221 and the second grid line 222 are both electrically connected to edge grid lines 5.

[0082] In this embodiment, the second grid line 222 is disconnected at the first connecting line 4, and the second grid line 222 is electrically connected to the undisconnected first grid line 221 through the edge grid line 5. This allows the current on the disconnected second grid line 222 to be transmitted to the solder ribbon through the edge grid line 5 and the first grid line 221, reducing the risk of uneven brightness and localized dark color during EL testing of the back contact battery. This improves the brightness uniformity of the EL test and reduces the risk of reduced output power of the back contact battery due to the inability to collect current on the disconnected second grid line 222, thereby improving the output power of the back contact battery.

[0083] In some embodiments, the first grid line 221 can be in direct contact with the solder ribbon of the same polarity, so that the first grid line 221 is directly electrically connected to the solder ribbon, thereby simplifying the structure of the back contact battery.

[0084] In other embodiments, the first grid line 221 extends along the first direction X and is electrically connected to the second pad 32. The second pad 32 is welded and fixed to the solder strip of the same polarity and electrically connected, so that the first grid line 221 and the solder strip of the same polarity are indirectly electrically connected through the second pad 32, thereby improving the stability of the electrical connection between the first grid line 221, the second grid line 222 and the solder strip, and thus improving the performance of the back contact battery.

[0085] The current transmitted on the first gate line 221 consists of two parts: one part is the current collected by the first gate line 221 itself, and the other part is the current collected by the second gate line 222 and transmitted to the first gate line 221. Therefore, the width of the first gate line 221 in the second direction Y is greater than the width of the second gate line 222 in the second direction Y, so as to improve the current transmission capability of the first gate line 221 and thus improve the output power of the back contact battery.

[0086] In the first direction X, the length of the first grid line 221 is L1, and the sum of the lengths of the multiple second grid lines 222 is L2. Here, L2 refers to the total length of the second grid lines 222 that transmit current to the first grid line 221. L2≤L1, that is, the length of the first grid line 221 is not less than the total length of the second grid lines 222 that are electrically connected to it, so as to improve the current transmission capability of the first grid line 221 and thus improve the output power of the back contact battery.

[0087] The relationship between the length L1 of the first gate line 221 and the total length L2 of the second gate line 222 satisfies: 1≤L1 / L2≤1.5. For example, the ratio of L1 to L2 can be 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, etc.

[0088] If the ratio of L1 to L2 is small, the length of the first grid line 221 is small and the total length of the second grid line 222 is large, resulting in poor current transmission capability of the first grid line 221, which in turn affects the output power of the back contact battery.

[0089] If the ratio of L1 to L2 is large, the length of the first grid line 221 is large and the total length of the second grid line 222 is small, resulting in a lower current collection efficiency of the second grid line 222 and an increase in the loss of the first grid line 221 during current transmission, which in turn affects the output power of the back contact battery.

[0090] Therefore, 1≤L1 / L2≤1.5 can improve the current transmission capability of the first grid line 221 and the current collection efficiency of the second grid line 222, thereby improving the brightness uniformity of the EL test and the output power of the back contact battery.

[0091] For example, 1≤L1 / L2≤1.1, and the ratio of L1 to L2 can be 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, etc.

[0092] For example, 1.1≤L1 / L2≤1.2, and the ratio of L1 to L2 can be 1.1, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.2, etc.

[0093] For example, 1.2≤L1 / L2≤1.3, and the ratio of L1 to L2 can be 1.2, 1.21, 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1.28, 1.29, 1.3, etc.

[0094] For example, 1.3≤L1 / L2≤1.4, and the ratio of L1 to L2 can be 1.3, 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.4, etc.

[0095] For example, 1.4≤L1 / L2≤1.5, and the ratio of L1 to L2 can be 1.4, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49, 1.5, etc.

[0096] The width of the edge grid line 5 in the first direction X is H1, and the width of the second fine grid 22 electrically connected to the edge grid line 5 is H2, where H2 < H1. That is, the width of the edge grid line 5 is greater than the width of the second fine grid 22 electrically connected to it, so as to improve the current transmission capability of the edge grid line 5 and thereby improve the output power of the back contact battery.

[0097] Figure 7 This is a partial structural schematic diagram of a back-contact battery in some other embodiments. Also refer to... Figure 5 , Figure 6 and Figure 7 Multiple first pads 31 are arranged along the second direction Y. The first pad 31 located on the outermost side in the second direction Y is designated as the first edge pad 311. In the second direction Y, the first pad 31 located between two first edge pads 311 is designated as the middle pad 312. That is, in the second direction Y, the middle pad 312 is located on one side of the first edge pad 311.

[0098] like Figure 7 As shown, in the second direction Y, a plurality of first fine gates 21 and second fine gates 22 are provided between the first edge pad 311 and the edge of the body 1 to improve the current collection efficiency of the back contact battery, thereby improving the output power of the back contact battery.

[0099] In some embodiments, such as Figure 7 As shown, the first connection line 4 includes a main connection line 41. One end of the main connection line 41 is electrically connected to the first edge pad 311, and the other end of the main connection line 41 extends away from the central pad 312. Between the first edge pad 311 and the edge of the body 1, the first fine gate 21 is electrically connected to the main connection line 41, and the second fine gate 22 is insulated from the main connection line 41. That is, a portion of the second gate line 222 and the main connection line 41 are arranged along the first direction Z, and the first gate line 221 and the main connection line 41 are arranged along the second direction Y.

[0100] In this embodiment, between the first edge pad 311 and the edge of the body 1, the first fine gate 21 is electrically connected to the main connection line 41, so that the current on the first fine gate 21 can be transmitted to the solder strip through the main connection line 41 and the first edge pad 311. This reduces the risk that the current on the first fine gate 21 between the first edge pad 311 and the edge of the body 1 cannot be collected, thereby improving the brightness uniformity of the EL test of the back contact battery and the output power of the back contact battery.

[0101] In the second direction Y, one or more first fine gates 21 may be provided between the first edge pad 311 and the first gate line 221. The first fine gates 21 have the same polarity as the first edge pad 311 and the opposite polarity to the first gate line 221.

[0102] In some embodiments, after the solder strip is welded and fixed to the first edge pad 311, the first fine grid 21 between the first edge pad 311 and the first gate line 221 can overlap with the solder strip to achieve electrical connection.

[0103] In other embodiments, such as Figure 7 As shown, in the second direction Y, at least one central pad 312 is provided between the first edge pad 311 and the first gate line 221. The first fine gate 21 between the first edge pad 311 and the first gate line 221 can be electrically connected to the central pad 312, and the central pad 312 between the first edge pad 311 and the first gate line 221 can be welded and fixed to the solder strip to improve the stability of the electrical connection between the solder strip and the first fine gate 21.

[0104] When at least one central pad 312 is provided between the first edge pad 311 and the first gate line 221, in some embodiments, such as Figure 7 As shown, the first edge pad 311 and the middle pad 312 are electrically connected only by solder strips.

[0105] Figure 8 This is a partial structural diagram of a back-contact battery in some embodiments. In other embodiments, such as... Figure 8 As shown, the first connecting line 4 also includes a secondary connecting line 42, the two ends of which are respectively connected to the adjacent first pad 31. For example, as shown... Figure 8 As shown, the two ends of the secondary connection line 42 are connected to the adjacent first edge pad 311 and the middle pad 312 respectively, that is, the first edge pad 311 and the middle pad 312 are electrically connected through the secondary connection line 42.

[0106] In this embodiment, when the solder strip separates from the first edge pad 311, causing electrical connection failure, the current on the first fine gate 21, which is electrically connected to the first edge pad 311, can be transmitted to the solder strip through the first edge pad 311, the secondary connection line 42, and the middle pad 312, thereby reducing the risk that the current on part of the first fine gate 21 cannot be collected due to the separation of the first edge pad 311 from the solder strip.

[0107] When the electrical connection between the solder strip and the central pad 312 fails, the current on the first fine gate 21, which is electrically connected to the central pad 312, can be transmitted to the solder strip through the central pad 312, the secondary connection line 42 and the first edge pad 311, thereby reducing the risk that the current on part of the first fine gate 21 cannot be collected due to the separation of the central pad 312 from the solder strip.

[0108] Therefore, in this embodiment, the first edge pad 311 and the middle pad 312 are electrically connected through the secondary connection line 42, which reduces the risk that the current on part of the first fine grid 21 cannot be collected due to the failure of the electrical connection between the first edge pad 311 or the middle pad 312 and the solder strip. This is beneficial to improving the brightness uniformity of the EL test of the back contact battery and to improving the output power and performance of the back contact battery.

[0109] Figure 8 An example is shown where adjacent first edge pads 311 and middle pads 312 are electrically connected via a secondary connection line 42.

[0110] In some embodiments, adjacent central pads 312 may also be electrically connected via secondary connection lines 42. Figure 9 This is a partial structural diagram of a back-contact battery in some embodiments. For example... Figure 9 As shown, the central pad 312 includes at least a first central pad 312A, a second central pad 312B, and a third central pad 312C arranged along the second direction Y. The secondary connection line 42 includes at least a first segment 421 and a second segment 422. The two ends of the first segment 421 are electrically connected to the first central pad 312A and the second central pad 312B, respectively. The two ends of the second segment 422 are electrically connected to the second central pad 312B and the third central pad 312C, respectively. A portion of the second gate line 222 is arranged along the first direction with the first segment 421, and a portion of the second gate line 222 is arranged along the first direction with the second segment 422.

[0111] In this embodiment, adjacent middle pads 312 are electrically connected by a secondary connection line 42, which reduces the risk that the current on part of the first fine grid 21 cannot be collected due to the failure of the electrical connection between the middle pads 312 and the solder strip. This is beneficial to improving the brightness uniformity of the EL test of the back contact battery and to improving the output power and performance of the back contact battery.

[0112] like Figure 9 As shown, in the first direction X, the width of the main connecting line 41 is greater than the width of the secondary connecting line 42.

[0113] In this embodiment, the main connection line 41 needs to transmit the current of multiple first fine gates 21. Therefore, the width of the main connection line 41 is greater than the width of the secondary connection line 42, which can improve the current transmission efficiency of the main connection line 41 and is beneficial to improving the output power and performance of the back contact battery.

[0114] The number of unbroken first grid lines 221 in the second direction Y can be one or more. When there are multiple first grid lines 221 in the second direction Y, L2 is the sum of the lengths of the second grid lines 222 between two adjacent first grid lines 221, and L1 is the length of one of the first grid lines 221 in the first direction X.

[0115] The first gate line 221 and the second gate line 222 can be arranged periodically in the second direction Y. The specific arrangement of the first gate line 221 and the second gate line 222 is not specifically limited in the embodiments of this application.

[0116] When the number of first grid lines 221 in the second direction Y is multiple Figure 10 This is a partial structural diagram of a back-contact battery in some embodiments, such as... Figure 10 As shown, multiple first gate lines 221 are arranged at intervals along the second direction, and multiple central pads 312 are provided between two adjacent first gate lines 221.

[0117] In this embodiment, a plurality of first grid lines 221 are provided in the second direction Y. The current of a portion of the interrupted second grid lines 222 can be transmitted through one first grid line 221, and the current of another portion of the interrupted second grid lines 222 can be transmitted through another first grid line 221, thereby reducing the current transmitted by a single first grid line 221. This reduces the current transmission capacity required by a single first grid line 221, thereby adaptively reducing the width and length of a single first grid line 221. Under the premise of meeting the output power of the back contact battery, the size of the first grid line 221 is reduced, and the material cost of the first grid line 221 is reduced.

[0118] In some embodiments, a plurality of first gate lines 221 arranged along the second direction Y are all connected to the same edge gate line 5.

[0119] In other embodiments, such as Figure 10 As shown, the edge gate line 5 includes a first edge gate line 51 and a second edge gate line 52. The first edge gate line 51 and the first edge pad 311 are distributed along the first direction X, and the second edge gate line 52 and a portion of the central pad 312 are distributed along the first direction X. The first edge gate line 51 and the second edge gate line 52 are distributed along the second direction Y.

[0120] In this embodiment, a portion of the first grid line 221 is electrically connected to the first edge grid line 51, and a portion of the first grid line 221 is electrically connected to the second edge grid line 52. This can optimize the current distribution on the back contact battery, which is beneficial to reducing losses during current transmission and improving the output power of the back contact battery.

[0121] Also refer to Figure 9 and Figure 10In the first direction X, the width of the first edge gate line 51 is H1, and the width of the second edge gate line 52 is H2, where H2 < H1, meaning the width of the first edge gate line 51 is greater than the width of the second edge gate line 52.

[0122] In this embodiment, Figure 9 and Figure 10 The example shows that a portion of the first edge grid line 51 is located at the chamfer of the body 1. Widening the first edge grid line 51 can improve the current transmission capability of the first edge grid line 51, thereby improving the current collection efficiency at the edge of the back contact battery and reducing the problem of the back contact battery edge being dark and black during EL testing. This is to improve the brightness uniformity of the back contact battery during EL testing and increase the output power of the back contact battery.

[0123] In some embodiments, the first edge gate line 51 is disconnected from the second edge gate line 52, that is, no current is transmitted between the first edge gate line 51 and the second edge gate line 52.

[0124] In other embodiments, reference is also made to Figure 9 and Figure 10 The first edge grid line 51 and the second edge grid line 52 are electrically connected, that is, current can be transmitted between the first edge grid line 51 and the second edge grid line 52 to optimize the current transmission path, which helps to reduce the loss of current transmission and thus improve the output power of the back contact battery.

[0125] Also refer to Figure 9 and Figure 10 In the first direction X, the first pad 31 is located on the side closest to the edge of the body 1. That is, the pad 3 located on the outermost side in the first direction X is referred to as the first pad 31 mentioned above, so as to shorten the current transmission path between the second gate line 222 and the edge gate line 5, thereby reducing the current transmission loss.

[0126] Figure 11 This is a partial structural diagram of a back-contact battery in some embodiments. For example... Figure 11 As shown, the back contact battery also includes a second pad 32. In the first direction X, the second pad 32 is located on the side of the first pad 31 away from the edge grid line 5. The second pad 32 is electrically connected to the second fine grid 22 and is insulated from the first fine grid 21. A plurality of second pads 32 are arranged along the second direction Y.

[0127] like Figure 11 As shown, the second fine gate 22 also includes a third gate line 223. In the first direction X, a portion of the second pad 32 is connected to the first gate line 221 and the third gate line 223 on both sides respectively.

[0128] like Figure 11As shown, in the second direction Y, the width of the first gate line 221 is greater than the width of the third gate line 223, and the width of the third gate line 223 is greater than or equal to the width of the second gate line 222.

[0129] In this embodiment, the width of the first gate line 221 is greater than the width of the third gate line 223, which can improve the current transmission capability of the first gate line 221, so as to improve the output power of the back contact battery.

[0130] like Figure 11 As shown, the second pad 32 includes the second edge pad 321 located on the outermost side in the second direction Y. The back contact battery also includes a second connecting line 6. One end of the second connecting line 6 is electrically connected to the second edge pad 321, and the other end extends in a direction close to the edge of the body 1. That is, the second connecting line 6 and the main connecting line 41 are arranged along the first direction X.

[0131] like Figure 11 As shown, a first fine gate 21 and a second fine gate 22 are provided between the main connection line 41 and the second connection line 6. One end of the first fine gate 21 is connected to the main connection line 41, and the other end extends towards the second connection line 6, leaving a gap between the first fine gate 21 and the second connection line 6, so that the first fine gate 21 is insulated from the second connection line 6. A portion of the second fine gate 22 is electrically connected to the second edge pad 321, and a portion of the second fine gate 22 is electrically connected to the second connection line 6 and insulated from the main connection line 41.

[0132] In this embodiment, between the second edge pad 321 and the edge of the body 1, the second fine gate 22 is electrically connected to the second connecting line 6, so that the current on the second fine gate 22 between the second edge pad 321 and the edge of the body 1 can be transmitted to the solder ribbon through the second connecting line 6 and the second edge pad 321. This reduces the risk that the current on the second fine gate 22 between the second edge pad 321 and the edge of the body 1 cannot be collected, thereby improving the brightness uniformity of the EL test of the back contact battery and the output power of the back contact battery.

[0133] like Figure 11 As shown, the back contact battery also includes a third connecting line 7, which is electrically connected to the adjacent second pad 32 in the second direction Y.

[0134] In this embodiment, adjacent second pads 32 are electrically connected by a third connecting line 7, which reduces the risk that the current on some of the second fine grids 22 cannot be collected due to the failure of the electrical connection between the second pads 32 and the solder strip. This is beneficial to improving the brightness uniformity of the EL test of the back contact battery and to improving the output power and performance of the back contact battery.

[0135] Figure 12 This is a partial structural diagram of a back-contact battery in some embodiments. For example... Figure 12 As shown, the back contact battery also includes a third pad 33. In the first direction X, the third pad 33 is located on the side of the first pad 31 away from the edge grid line 5. The third pad 33 and the second pad 32 are arranged alternately in the first direction X. The third pad 33 is electrically connected to the first fine grid 21 and is insulated from the second fine grid 22. A plurality of third pads 33 are arranged along the second direction Y.

[0136] like Figure 12 As shown, the third pad 33 includes the third edge pad 331 located on the outermost side in the second direction Y. The back contact battery also includes a fourth connecting line 8. One end of the fourth connecting line 8 is electrically connected to the third edge pad 331, and the other end extends towards the edge of the body 1. That is, the second connecting line 6 and the fourth connecting line 8 are arranged along the first direction X.

[0137] like Figure 12 As shown, a first fine gate 21 and a second fine gate 22 are provided between the second connecting line 6 and the fourth connecting line 8. One end of the second fine gate 22 is connected to the second connecting line 6, and the other end extends towards the fourth connecting line 8, leaving a gap between the second fine gate 22 and the fourth connecting line 8, so that the second fine gate 22 is insulated from the fourth connecting line 8. A portion of the first fine gate 21 is electrically connected to the third edge pad 331, and a portion of the first fine gate 21 is electrically connected to the fourth connecting line 8 and insulated from the second connecting line 6.

[0138] In this embodiment, between the edge of the third edge pad 331 and the edge of the body 1, the first fine gate 21 is electrically connected to the fourth connecting line 8, so that the current on the first fine gate 21 between the edge of the third edge pad 331 and the edge of the body 1 can be transmitted to the solder strip through the fourth connecting line 8 and the third edge pad 331. This reduces the risk that the current on the first fine gate 21 between the edge of the third edge pad 331 and the edge of the body 1 cannot be collected, thereby improving the brightness uniformity of the EL test of the back contact battery and the output power of the back contact battery.

[0139] like Figure 12 As shown, the back contact battery also includes a fifth connecting line 9, and in the second direction Y, the two ends of the fifth connecting line 9 are electrically connected to the adjacent third pad 33 respectively.

[0140] In this embodiment, adjacent third pads 33 are electrically connected by a fifth connecting line 9, which reduces the risk that the current on some of the first fine grid 21 cannot be collected due to the failure of the electrical connection between the third pad 33 and the solder strip. This is beneficial to improving the brightness uniformity of the EL test of the back contact battery and to improving the output power and performance of the back contact battery.

[0141] A second aspect of this application provides a back-contact stacked battery. Figure 13The back-contact stacked battery provided in this application is illustrated in some embodiments as follows: Figure 13 As shown, the back contact stacked cell 303 includes a perovskite top cell 302 and a back contact bottom cell 301 stacked along the third direction Z. The perovskite top cell 302 and the back contact bottom cell 301 are electrically connected to the light-facing surface. The back contact bottom cell 301 is constructed as the back contact cell described above.

[0142] The perovskite top-mounted solar cell 302 is a thin-film solar cell using perovskite material as the photoactive layer. The structure of the perovskite top-mounted solar cell 302 mainly consists of the following key components: a transparent conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode. These components work together to enable the perovskite top-mounted solar cell 302 to effectively absorb sunlight and convert it into electrical energy. The perovskite material in the light-absorbing layer has excellent light absorption performance, absorbing a wider spectral range and effectively converting short-wavelength spectra, giving the perovskite top-mounted solar cell 302 high photoelectric conversion efficiency.

[0143] A third aspect of the embodiments of this application provides a photovoltaic module. Figure 14 The following are schematic diagrams of the structure of the photovoltaic module provided in this application in some embodiments, such as... Figure 14 As shown, the photovoltaic module includes a cover plate 10, an encapsulation layer 20, and a cell layer 30.

[0144] The cover plate 10 includes a first cover plate 101 and a second cover plate 102 arranged along the third direction Z. The encapsulation layer 20 and the battery layer 30 are located between the first cover plate 101 and the second cover plate 102. A portion of the encapsulation layer 20 is located between the battery layer 30 and the first cover plate 101, and another portion of the encapsulation layer 20 is located between the battery layer 30 and the second cover plate 102, so as to achieve the encapsulation and fixation of the cover plate 10 and the battery layer 30.

[0145] At least one of the first cover plate 101 and the second cover plate 102 is made of a light-transmitting material, which is beneficial to improving the photoelectric conversion efficiency of the photovoltaic module.

[0146] The first cover plate 101 can be made of one of the following rigid materials: tempered glass, PET (polyethylene terephthalate), or PC (polycarbonate). Alternatively, the first cover plate 101 can be made of one of the following flexible materials: PVF (polyvinyl fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), or PVDF (polyvinylidene fluoride). All of these materials have high light transmittance, ensuring that more light reaches the battery layer, thereby increasing the light absorption of the photovoltaic module and improving its photoelectric conversion efficiency.

[0147] The material of the second cover plate 102 can be one of rigid materials such as tempered glass, PET (polyethylene terephthalate), or PC (polycarbonate). Alternatively, the material of the second cover plate 102 can be one of flexible materials such as PVF (polyvinyl fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), or PVDF (polyvinylidene fluoride).

[0148] The materials of the first cover plate 101 and the second cover plate 102 can be the same or different.

[0149] like Figure 14 As shown, the encapsulation layer 20 includes a first adhesive film 201 and a second adhesive film 202. In the third direction Z, a portion of the structure of the first adhesive film 201 is located between the battery layer 30 and the first cover plate 101, and a portion of the structure of the second adhesive film 202 is located between the battery layer and the second cover plate 102.

[0150] The first encapsulant film 201 is made of one of the following polyolefins: EVA (Ethylene-Vinyl Acetate Copolymer), POE (Polyolefin Elastomer), and PVB (Polyvinyl Butyral). These materials have high light transmittance, which is beneficial for improving the photoelectric conversion efficiency of photovoltaic modules. The first encapsulant film 201 can also be an EPE film (EVA-POE-EVA co-extrusion structure) or an EP film (EVA-POE co-extrusion structure).

[0151] The material of the second film 202 is one of polyolefins such as EVA (Ethylene-Vinyl Acetate Copolymer), POE (Polyolefin Elastomer), and PVB (Polyvinyl Butyral). The second film 202 can also be an EPE film (EVA-POE-EVA co-extrusion structure) or an EP film (EVA-POE co-extrusion structure).

[0152] The materials of the first adhesive film 201 and the second adhesive film 202 can be the same or different.

[0153] The battery layer 30 contains multiple battery strings connected in series or in parallel. Each battery string consists of multiple battery cells (including but not limited to monocrystalline silicon battery cells and polycrystalline silicon battery cells) connected in series, and adjacent battery cells are connected by solder strips.

[0154] Figure 15 for Figure 14 The battery layer 30 is shown in a schematic diagram in some embodiments. For example... Figure 15 As shown, the battery layer 30 includes multiple battery cells 307. Solder ribbons 308 are fixed to the battery cells 307, meaning the solder ribbons 308 are welded to the solder pads on the battery cells 307. The solder ribbons 308 are used to achieve electrical connections between adjacent battery cells 307 to form a battery string. The battery cells 307 also include busbars 309. Along the second direction Y, the busbars 309 are located on both sides of the battery string, used to achieve series or parallel connections between multiple battery strings.

[0155] The battery cell 307 can be either the back contact battery or the back contact stacked battery 303 mentioned above.

[0156] The battery layer 30 may contain only the aforementioned back contact battery, or only the aforementioned back contact stacked battery 303, or both the aforementioned back contact battery and the aforementioned back contact stacked battery 303. This application embodiment does not impose any special limitations on the number, type, series / parallel connection method, etc., of the battery cells included in the battery layer 30. The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-contact battery, characterized in that, The back contact battery includes: Ontology(1); A fine grid extending along a first direction (X), the fine grid comprising a first fine grid (21) and a second fine grid (22) arranged alternately at intervals along a second direction (Y). The first pad (31) is electrically connected to the first fine gate (21), and the first pad (31) is insulated from the second fine gate (22); The first connecting line (4) is electrically connected to the first pad (31); The second fine grid (22) includes a first grid line (221) and a plurality of second grid lines (222). Both the first grid line (221) and the second grid lines (222) are insulated from the first connecting line (4). The first grid line (221) and the first connecting line (4) are arranged along the second direction (Y), and the second grid lines (222) and the first connecting line (4) are arranged along the first direction (X). Edge gate line (5), in the first direction (X), the fine gate is located on one side of the edge gate line (5), and the first gate line (221) and the second gate line (222) are both electrically connected to the edge gate line (5); In the first direction (X), the length of the first gate line (221) is L1, and the sum of the lengths of the plurality of second gate lines (222) is L2, where 1≤L1 / L2≤1.5; The edge grid line (5) includes a first edge grid line (51) and a second edge grid line (52), the first edge grid line (51) and the second edge grid line (52) are distributed along the second direction (Y), and the first grid line (221) is connected to the first edge grid line (51); In the first direction (X), the width of the first edge gate line (51) is greater than the width of the second edge gate line (52); In the second direction (Y), the width of the first edge gate line (51) remains constant, and the width of the second edge gate line (52) remains constant.

2. The back contact battery according to claim 1, characterized in that, A plurality of the first pads (31) are arranged in the second direction (Y), and the first pads (31) include the first edge pads (311) located on the outermost side in the second direction (Y). The first connecting line (4) includes a main connecting line (41), which is electrically connected to the first edge pad (311).

3. The back contact battery according to claim 2, characterized in that, The first pad (31) further includes a central pad (312), which is located on one side of the first edge pad (311) in the second direction (Y); In the second direction (Y), at least one of the central pads (312) is provided between the first edge pad (311) and the first gate line (221).

4. The back contact battery according to claim 2, characterized in that, The first pad (31) further includes a central pad (312), which is located on one side of the first edge pad (311) in the second direction (Y); The central pad (312) includes at least a first central pad (312A), a second central pad (312B), and a third central pad (312C) arranged along the second direction (Y). The first connecting line (4) further includes a secondary connecting line (42), which includes at least a first segment (421) and a second segment (422). The two ends of the first segment (421) are electrically connected to the first middle pad (312A) and the second middle pad (312B) respectively, and the two ends of the second segment (422) are electrically connected to the second middle pad (312B) and the third middle pad (312C) respectively. A portion of the second gate line (222) and the first segment (421) are arranged along the first direction (X).

5. The back contact battery according to claim 4, characterized in that, In the first direction (X), the width of the main connecting line (41) is greater than the width of the secondary connecting line (42).

6. The back contact battery according to claim 4, characterized in that, Multiple first gate lines (221) are arranged at intervals along the second direction (Y), and multiple central pads (312) are provided between two adjacent first gate lines (221).

7. The back contact battery according to claim 4, characterized in that, The first edge gate line (51) and the first edge pad (311) are distributed along the first direction (X), and the second edge gate line (52) and the middle pad (312) are distributed along the first direction (X).

8. The back contact battery according to claim 7, characterized in that, The first edge gate line (51) is electrically connected to the second edge gate line (52).

9. The back contact battery according to any one of claims 1 to 8, characterized in that, The back contact battery also includes a second pad (32), which is located on the side of the first pad (31) away from the edge grid line (5) in the first direction (X); The second fine gate (22) also includes a third gate line (223), and in the first direction (X), a portion of the second pad (32) is connected to the first gate line (221) and the third gate line (223) on both sides respectively. In the second direction (Y), the width of the first gate line (221) is greater than the width of the third gate line (223).

10. The back contact battery according to any one of claims 1 to 8, characterized in that, The width of the edge gate line (5) is H1, and the width of the second fine gate (22) electrically connected to the edge gate line (5) is H2, where H2 < H1.

11. The back contact battery according to any one of claims 1 to 8, characterized in that, The back contact battery also includes a second pad (32), which is located on the side of the first pad (31) away from the edge grid line (5) in the first direction (X). The second pad (32) is electrically connected to the second fine grid (22) and is insulated from the first fine grid (21). Multiple second pads (32) are arranged along the second direction (Y), and the second pads (32) include a second edge pad (321) located on the outermost side in the second direction (Y). The back contact battery also includes a second connecting line (6), which is electrically connected to the second edge pad (321); A portion of the second fine gate (22) is electrically connected to the second edge pad (321), and a portion of the second fine gate (22) is electrically connected to the second connection line (6).

12. The back contact battery according to any one of claims 1 to 8, characterized in that, The back contact battery also includes a second pad (32). In the first direction (X), the second pad (32) is located on the side of the first pad (31) away from the edge grid line (5). The second pad (32) is electrically connected to the second fine grid (22) and is insulated from the first fine grid (21). Multiple second pads (32) are arranged along the second direction (Y); The back contact battery also includes a third connecting line (7), which is electrically connected at both ends to the adjacent second pad (32) in the second direction (Y).

13. A back-contact stacked battery, characterized in that, The back contact stacked battery includes: A back-contact bottom battery, wherein the back-contact bottom battery is the back-contact battery according to any one of claims 1 to 12; A perovskite top cell, wherein the perovskite top cell is electrically connected to the light-facing surface of the back contact bottom cell.

14. A photovoltaic module, characterized in that, The photovoltaic module includes a cover plate (10), an encapsulation layer (20), and a battery layer (30). The battery layer (30) includes a plurality of back-contact batteries as described in any one of claims 1 to 12, and / or the battery layer (30) includes a plurality of back-contact stacked batteries as described in claim 13.

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