Back contact cell, back contact laminated cell and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic cells, in particular to a back contact cell, a back contact laminated cell and a photovoltaic module. The back contact battery comprises a body, a fine grid, a first bonding pad, a first connecting line and an edge grid line. The fine grid comprises a first fine grid and a second fine grid, the first connecting line and the first fine grid are electrically connected with the first bonding pad, and the second fine grid is insulated from the first bonding pad. The second fine grid comprises a first grid line and a plurality of second grid lines which are arranged in the second direction, the first grid line and the first connecting line are arranged in the second direction, and the second grid line and the first connecting line are arranged in the first direction. In the first direction, the fine grids are located on one sides of the edge grid lines, the first grid lines and the second grid lines are electrically connected with the edge grid lines, the brightness uniformity of EL testing and the output power of the back contact battery are improved, and in the first direction, the length of the first grid lines is not smaller than the sum of the lengths of the multiple second grid lines, so that the current transmission capacity of the first grid lines is improved, and the reliability of the back contact battery is improved. Therefore, the output power of the back contact battery is improved.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic cells, and in particular, to a back-contact cell, a back-contact stacked cell, and a photovoltaic module. Background Art

[0002] A back-contact cell includes fine grids and pads disposed on the backlight side. The pads are electrically connected to the grid lines, and the pads are used for welding and fixing with solder ribbons to collect current.

[0003] When the electrical connection between some grid lines and the pads is disconnected, the brightness is uneven and the local color is blackish during the EL test of the back-contact cell. The photoelectric conversion efficiency of the blackish part is relatively low or even zero, resulting in a low output power of the back-contact cell.

[0004] Therefore, how to improve the brightness uniformity of the EL test to improve the output power is an important problem to be solved in this field. Summary of the Invention

[0005] In view of this, the present application provides a back-contact cell, a back-contact stacked cell, and a photovoltaic module, which can improve the brightness uniformity of the EL test and the output power.

[0006] The first aspect of the present application provides a back-contact cell, including a body, fine grids, a first pad, a first connection line, and edge grid lines. The fine grids include first fine grids and second fine grids that are alternately arranged at intervals along a second direction. The first pad is electrically connected to the first fine grids and insulated from the second fine grids. The first connection line is electrically connected to the first pad. The second fine grids include a first grid line and a plurality of second grid lines. Both the first grid line and the second grid lines are insulated from the first connection line. The first grid line and the first connection line are arranged along the second direction, and the second grid lines and the first connection line are arranged along a first direction. In the first direction, the fine grids are located on one side of the edge grid lines. Both the first grid line and the second grid lines are electrically connected to the edge grid lines. 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, and L2 ≤ L1.

[0007] In the present application, the second grid lines are disconnected at the first connection line, reducing the risk of short circuit of the back-contact cell caused by the second fine grids contacting the first connection line in the first direction, and improving the performance of the back-contact cell.

[0008] The second grid lines are electrically connected to the unbroken first grid line through the edge grid lines, enabling the current on the disconnected second grid lines to be transmitted to the solder ribbon through the edge grid lines and the first grid line. This reduces the risk of uneven brightness and local blackish color during the EL test of the back-contact cell, improves the brightness uniformity of the EL test, reduces the risk of reduction in the output power of the back-contact cell caused by the inability to collect the current on the disconnected second grid lines, and improves the output power of the back-contact cell.

[0009] L2 ≤ L1, that is, the length of the first gate line is not less than the total length of the second gate lines electrically connected thereto, so as to improve the current transmission capacity of the first gate line and facilitate the improvement of the output power of the back-contact battery.

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

[0011] In some possible designs, the first pad further includes a middle pad. In the second direction, the middle pad is located on one side of the first edge pad. At least one middle pad is provided between the first edge pad and the first gate line in the second direction.

[0012] In some possible designs, the first pad further includes a middle pad. In the second direction, the middle pad is located on one side of the first edge pad. The middle pad at least includes a first middle pad, a second middle pad, and a third middle pad arranged in the second direction. The first connection line further includes auxiliary connection lines. The auxiliary connection lines at least include a first section and a second section. Two ends of the first section are electrically connected to the first middle pad and the second middle pad respectively. Two ends of the second section are electrically connected to the second middle pad and the third middle pad respectively. A part of the second gate lines is arranged along the first direction with the first section, and a part of the second gate lines is arranged along the first direction with the second section.

[0013] In some possible designs, in the first direction, the width of the main connection line is greater than the width of the auxiliary connection lines.

[0014] In some possible designs, multiple first gate lines are arranged at intervals in the second direction. Multiple middle 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 the first edge pad are distributed along the first direction. The second edge gate line and the middle pad are distributed along the first direction. And the first edge gate line and the second edge gate line are distributed along the 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 further includes a second pad, and in the first direction, the second pad is located on a side of the first pad away from the edge grid line. The second fine grid further includes a third grid line, and in the first direction, two sides of a portion of the second pad are respectively connected to the first grid line and the third grid line. 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

[0020] In some possible designs, the back contact battery further includes a second pad, the second pad is located on a side of the first pad away from the edge grid line in the first direction, the second pad is electrically connected to the second fine grid, and the second pad is insulated from the first fine grid. A plurality of second pads are arranged along the second direction, the second pads include a second edge pad located at the outermost side in the second direction, and the back contact battery further includes a second connecting line, the second connecting line is 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 further includes a second pad, which is located on a side of the first pad away from the edge grid line in the first direction, is electrically connected to the second fine grid, is insulated from the first fine grid, and a plurality of second pads are arranged along the second direction. The back contact battery further includes a third connecting wire, which is electrically connected at both ends to adjacent second pads in the second direction.

[0022] A second aspect of the present application provides a back-contact stack cell, comprising a back-contact bottom cell and a perovskite top cell, wherein the back-contact bottom cell is the back-contact cell described in any one of the above items, and the light-facing surface of the perovskite top cell is electrically connected to the back-contact bottom cell.

[0023] A third aspect of the present application provides a photovoltaic module, comprising a cover plate, an encapsulation layer and a battery layer, wherein the battery layer comprises a plurality of back-contact batteries as described in any one of the above items, and / or the battery layer comprises a plurality of the above-mentioned back-contact stacked batteries.

[0024] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor. ​

[0026] Figure 1 Schematic diagram of the structure of the back-contact battery provided by this application in some embodiments; Figure 2 Schematic diagram of the structure of the back-contact battery provided by this application in some other embodiments; Figure 3 Schematic diagram of the structure of the back-contact battery provided by this application in still some other embodiments; Figure 4 Schematic diagram of the structure of the back-contact battery provided by this application in still some other embodiments; Figure 5 Schematic diagram of the structure of the back-contact battery provided by this application in still some other embodiments; Figure 6 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in some embodiments in Figure 7 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in some other embodiments in Figure 8 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in still some other embodiments in Figure 9 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in still some other embodiments in Figure 10 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in still some other embodiments in Figure 11 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in still some other embodiments in Figure 12 is Figure 5 Partial schematic diagram of the structure of the back-contact battery in still some other embodiments in Figure 13 Schematic diagram of the stacked structure of the back-contact stacked battery provided by this application in some embodiments; Figure 14 Cross-sectional view of the photovoltaic module provided by this application in some embodiments; Figure 15 is Figure 14 Schematic diagram of the connection structure of the battery layer in some embodiments in

[0027] Reference numerals: 10 - Cover plate; 101 - First cover plate; 102 - Second cover plate; 20 - Encapsulation layer; 201 - First adhesive film; 202 - Second adhesive film; 30 - Battery layer; 301 - Back - contact bottom cell; 302 - Perovskite top cell; 303 - Back - contact stacked cell; 304 - Whole cell; 305 - Half - sliced cell; 306 - Quarter - sliced cell; 307 - Cell slice; 308 - Solder ribbon; 309 - Bus bar; 1 - Body; 2 - Fine grid; 21 - First fine grid; 22 - Second fine grid; 221 - First grid line; 222 - Second grid line; 223 - Third grid line; 3 - Pad; 31 - First pad; 311 - First edge pad; 312 - Middle pad; 312A - First middle pad; 312B - Second middle pad; 312C - Third middle pad; 32 - Second pad; 321 - Second edge pad; 33 - Third pad; 331 - Third edge pad; 4 - First connection line; 41 - Main connection line; 42 - Sub - connection line; 421 - First segment; 422 - Second segment; 5 - Edge grid line; 51 - First edge grid line; 52 - Second edge grid line; 6 - Second connection line; 7 - Third connection line; 8 - Fourth connection line; 9 - Fifth connection line; X - First direction; Y - Second direction; Z - Third direction. Detailed implementation mode

[0028] For a better understanding of the technical solution of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0029] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0030] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0031] It should be understood that the term " / and" used herein is only a description of the associated relationship of the associated objects, indicating that there can be three relationships. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0032] The first aspect of the embodiments of the present application provides a back contact battery. In some embodiments, the type of the back contact battery cell can be one of an Interdigitated Back Contact (IBC) battery, a Heterojunction Back Contact (HBC) battery, and a Tunnel Oxide Back Contact (TBC) battery.

[0033] For an IBC battery, along its thickness direction, the IBC battery sequentially includes a silicon nitride back layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an alumina passivation layer 14, a silicon nitride antireflection layer, and a silver metal electrode.

[0034] The IBC battery uses ion implantation technology to obtain P and N regions with good uniformity and precisely controllable junction depth. There are no grid lines blocking the front of the battery, which can eliminate the shading current loss of the metal electrode and maximize the utilization of incident photons. The short-circuit current of the IBC battery can be increased by about 7% compared with that of a conventional solar cell. Due to the back contact structure, there is no need to consider the problem of grid line blockage, and the grid line ratio can be appropriately widened, thereby reducing the series resistance and having a high fill factor. The surface passivation and surface light trapping structure can be optimized, and a lower front surface recombination rate and surface reflection can be obtained.

[0035] For an HBC battery, the HBC battery combines the advantages of an IBC battery and a heterojunction battery well. Its front surface passivation layer uses hydrogenated amorphous silicon, and N-type and P-type amorphous silicon thin films are respectively deposited on the back to form a heterojunction.

[0036] The HBC battery makes full use of the excellent surface passivation performance of amorphous silicon. The heterojunction structure formed on the back has a good passivation effect, and can simultaneously achieve a higher short-circuit current and open-circuit voltage, thereby improving the photoelectric conversion efficiency.

[0037] For a TBC battery, the TBC battery combines the advantages of the tunneling oxide layer technology of Topcon and the back-arranged electrodes of IBC. The passivation effect and open-circuit voltage are significantly improved, and it can be economical while achieving a higher battery conversion efficiency.

[0038] The complete production process of the TBC battery mainly includes depositing a tunneling oxide layer and P+ polysilicon, depositing a passivation film, printing electrodes on the back of the silicon wafer, etc. The TBC battery needs to add related processes for the back electrodes such as masking, laser grooving, PN region preparation, and etching on the basis of the TOPCon production process. The masking is mainly completed by APCVD or PECVD, the preparation of the PN region is mainly completed by PECVD, the etching mainly uses traditional wet equipment, and the grooving process needs to be completed by a laser device.

[0039] The embodiments of the present application do not make special limitations on the specific types of back-contact batteries.

[0040] Figure 1 The following is a schematic structural diagram of the back-contact battery provided by the present application in some embodiments. As Figure 1 shown, in some embodiments, the back-contact battery is a whole-piece battery 304.

[0041] Figure 2 The following is a schematic structural diagram of the back-contact battery provided by the present application in some embodiments. As Figure 2 shown, in some other embodiments, the back-contact battery is a two-piece battery 305, that is, the whole-piece battery 304 is cut along the Figure 2 dotted line in it into two half pieces, and one of the half pieces is made into the two-piece battery 305.

[0042] Figure 3 The following is a schematic structural diagram of the back-contact battery provided by the present application in some embodiments. As Figure 3 shown, in still some other embodiments, the battery piece is a three-piece battery 306 or other multi-piece batteries. Taking the battery piece as the three-piece battery 306 as an example, the whole-piece battery 304 is cut along the Figure 3 dotted line in it into three pieces, and one of the pieces is made into the three-piece battery 306.

[0043] The embodiments of the present application do not make special limitations on the specific types of back-contact batteries, that is, the back-contact battery can be a whole-piece battery, a two-piece battery, a three-piece battery or other multi-piece batteries.

[0044] The back-contact battery can be constructed as a main-gridless battery or a main-grid battery. The embodiments of the present application do not make special limitations on the number of main grids of the back-contact battery.

[0045] Figure 4 The following is a schematic structural diagram of the back-contact battery in some embodiments, Figure 4 illustrating that the back-contact battery is a whole-piece battery.

[0046] Figure 5 The following is a schematic structural diagram of the back-contact battery in some embodiments, Figure 5 illustrating that the back-contact battery is a two-piece battery.

[0047] The following will take the back-contact battery as a two-piece battery as an example to discuss in detail the specific structure of the back-contact battery.

[0048] As Figure 5As shown in the figure, the back-contact battery includes a body 1, and the body 1 has a light-facing surface and a backlight surface that are oppositely arranged along its thickness direction. Among them, the light-facing surface refers to the side of the body 1 facing the sun when the back-contact battery is in the working state, and the backlight surface refers to the side of the body 1 facing away from the sun when the back-contact battery is in the working state. It can also be understood that the light-facing surface is the upper surface of the body 1, and the backlight surface is the lower surface of the body 1.

[0049] As Figure 5 shown in the figure, a fine grid 2 extending along the first direction X is provided on the backlight surface of the body 1, and a plurality of fine grids 2 are arranged along the second direction Y. Denote the thickness direction of the back-contact battery as the third direction Z, then both the first direction X and the second direction Y are perpendicular to the third direction Z. Exemplarily, 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.

[0050] As Figure 5 shown in the figure, the fine grid 2 includes a first fine grid 21 and a second fine grid 22 that are alternately arranged at intervals along the second direction Y. One of the first fine grid 21 and the second fine grid 22 is constructed as the negative electrode fine grid of the back-contact battery, and the other is constructed as the positive electrode fine grid of the back-contact battery.

[0051] As Figure 5 shown in the figure, the back-contact battery further includes a pad 3, and the pad 3 is electrically connected to the fine grid 2. The pad 3 is used for welding and fixing with a solder strip, so that a plurality of back-contact batteries are electrically connected.

[0052] The pad 3 includes a positive electrode pad and a negative electrode pad. The positive electrode pad is used for electrically connecting with the positive electrode fine grid and for welding and fixing with the positive electrode solder strip. The negative electrode pad is used for electrically connecting with the negative electrode fine grid and for welding and fixing with the negative electrode solder strip. A plurality of positive electrode pads are arranged in a positive electrode welding array along the second direction Y, and a plurality of negative electrode pads are arranged in a negative electrode welding array along the second direction Y. The positive electrode welding array and the negative electrode welding array are arranged alternately at intervals along the first direction X, so that the positive electrode solder strip and the negative electrode solder strip are arranged alternately at intervals along the first direction X.

[0053] The back-contact battery further includes a connecting wire provided on the backlight surface of the body 1. In the second direction Y, both ends of the connecting wire are electrically connected to adjacent pads 3 of the same polarity. Alternatively, in the second direction Y, one end of the connecting wire is electrically connected to the pad 3, and the other end extends towards 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 wire.

[0054] The connecting wire can be electrically connected to the first pad 31 or the second pad 32. Here, taking the first pad 31 as an example, the structural design of the pad 3, the connecting wire, and the fine grid 2 will be described in detail.

[0055] Figure 6 This is a schematic diagram of a partial structure of a back-contact battery in some embodiments. As Figure 6 shown, the back-contact battery includes a first connection line 4 disposed on the backlight surface of the body 1. The first connection line 4 is electrically connected to the first pad 31, that is, the first connection line 4 has the same polarity as the first fine grid 21 and the first pad 31, and has the opposite polarity to the second fine grid 22 and the second pad 32. The first connection line 4 needs to be insulated from the second fine grid 22 and the second pad 32 to reduce the risk of short circuit of the back-contact battery and improve the performance of the back-contact battery.

[0056] As Figure 6 shown, the second fine grid 22 includes a first grid line 221 and a plurality of second grid lines 222 arranged along the second direction Y. Both the first grid line 221 and the second grid lines 222 are insulated from the first connection line 4. The first grid line 221 and the first connection 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 connection line 4 and the first grid line 221. The second grid lines 222 and the first connection line 4 are arranged along the first direction X, that is, in the first direction X, the second grid lines 222 are located on one side or both sides of the first connection line 4.

[0057] In this embodiment, the second grid lines 222 are disconnected at the first connection line 4, reducing the risk of short circuit of the back-contact battery caused by the second fine grid 22 contacting the first connection line 4 in the first direction X, thereby improving the performance of the back-contact battery.

[0058] In some embodiments, the second grid lines 222 are disconnected at the first connection line 4, so that the current on some of the second grid lines 222 cannot be collected. When the back-contact battery is subjected to EL testing, the test brightness of the second grid lines 222 where the current cannot be collected is low, resulting in uneven brightness and partial black color during the EL testing of the back-contact battery. The optoelectronic conversion efficiency of the black-colored part is low or even zero, resulting in a low output power of the back-contact battery.

[0059] In view of this, in the embodiments of the present application, as Figure 6 shown, the back-contact battery further includes an edge grid line 5. In the first direction X, the fine grid 2 is located on one side of the edge grid line 5, and the first fine grid 21 and the second fine grid 22 are located on the same side of the edge grid line 5. Both the first grid line 221 and the second grid lines 222 are electrically connected to the edge grid line 5.

[0060] In this embodiment, the second gate line 222 is disconnected at the first connection line 4, and the second gate line 222 is electrically connected to the uninterrupted first gate line 221 through the edge gate line 5, so that the current on the disconnected second gate line 222 can be transmitted to the solder tape through the edge gate line 5 and the first gate line 221, reducing the risk of uneven brightness and partial black color during the EL test of the back-contact battery, thereby improving the brightness uniformity of the EL test and reducing the risk of power output reduction of the back-contact battery caused by the inability to collect the current on the disconnected second gate line 222, thereby improving the power output of the back-contact battery.

[0061] In some embodiments, the first gate line 221 can be in direct contact with the solder tape of the same polarity, so that the first gate line 221 is directly electrically connected to the solder tape to simplify the structure of the back-contact battery.

[0062] In other embodiments, the first gate 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 tape of the same polarity and electrically connected, so that the first gate line 221 is indirectly electrically connected to the solder tape of the same polarity through the second pad 32, so as to improve the stability of the electrical connection between the first gate line 221, the second gate line 222 and the solder tape, and further improve the performance of the back-contact battery.

[0063] The current transmitted on the first gate line 221 includes 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 to improve the current transmission ability of the first gate line 221, so as to improve the power output of the back-contact battery.

[0064] In the first direction X, the length of the first gate line 221 is L1, and the sum of the lengths of the multiple second gate lines 222 is L2. Here, L2 refers to the total length of the second gate lines 222 that transmit current to the first gate line 221, and L2≤L1, that is, the length of the first gate line 221 is not less than the total length of the second gate lines 222 electrically connected to it, so as to improve the current transmission ability of the first gate line 221, so as to improve the power output of the back-contact battery.

[0065] The relationship between the length L1 of the first gate line 221 and the total length L2 of the second gate lines 222 satisfies: 1≤L1 / L2≤1.5. Exemplarily, 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.

[0066] 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 lines 222 is large, resulting in poor current transmission ability of the first grid line 221, which in turn affects the output power of the back contact battery.

[0067] 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 lines 222 is small, resulting in low current collection efficiency of the second grid lines 222 and increasing the loss of the first grid line 221 during current transmission, which in turn affects the output power of the back contact battery.

[0068] Therefore, 1 ≤ L1 / L2 ≤ 1.5 can improve the current transmission ability of the first grid line 221, and can also improve the current collection efficiency of the second grid lines 222, thereby improving the brightness uniformity of the EL test and the output power of the back contact battery.

[0069] Exemplarily, 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.

[0070] Exemplarily, 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.

[0071] Exemplarily, 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.

[0072] Exemplarily, 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.

[0073] Exemplarily, 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.

[0074] 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 thereto, so as to improve the current transmission ability of the edge grid line 5 and thus improve the output power of the back contact battery.

[0075] Figure 7 Schematic diagram of the partial structure of the back-contact battery in some other embodiments. Also refer to Figure 5 , Figure 6 and Figure 7 , a plurality of first pads 31 are arranged along the second direction Y. Denote the first pad 31 located on the outermost side in the second direction Y as the first edge pad 311. In the second direction Y, denote the first pad 31 located between two first edge pads 311 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.

[0076] As Figure 7 shown, in the second direction Y, a plurality of first fine grids 21 and second fine grids 22 are arranged between the first edge pad 311 and the edge of the body 1 to improve the current collection efficiency of the back-contact battery, and thus improve the output power of the back-contact battery.

[0077] In some embodiments, as Figure 7 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 in a direction away from the middle pad 312. Between the first edge pad 311 and the edge of the body 1, the first fine grid 21 is electrically connected to the main connection line 41, and the second fine grid 22 is insulated from the main connection line 41. That is, a part of the second grid line 222 and the main connection line 41 are arranged along the first direction Z, and the first grid line 221 and the main connection line 41 are arranged along the second direction Y.

[0078] In this embodiment, between the first edge pad 311 and the edge of the body 1, the first fine grid 21 is electrically connected to the main connection line 41, so that the current on the first fine grid 21 can be transmitted to the solder tape through the main connection line 41 and the first edge pad 311, reducing the risk that the current on the first fine grid 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.

[0079] In the second direction Y, one or more first fine grids 21 may be arranged between the first edge pad 311 and the first grid line 221. The first fine grid 21 has the same polarity as the first edge pad 311 and the opposite polarity to the first grid line 221.

[0080] In some embodiments, after the solder tape is welded and fixed to the first edge pad 311, the first fine grid 21 between the first edge pad 311 and the first grid line 221 can overlap with the solder tape to achieve electrical connection.

[0081] In some other embodiments, as Figure 7As shown, in the second direction Y, at least one middle pad 312 is provided between the first edge pad 311 and the first gate line 221. The first fine grid 21 between the first edge pad 311 and the first gate line 221 can be electrically connected to the middle pad 312, and the middle 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 grid 21.

[0082] When at least one middle pad 312 is provided between the first edge pad 311 and the first gate line 221, in some embodiments, as Figure 7 shown, only the solder strip is electrically connected between the first edge pad 311 and the middle pad 312.

[0083] Figure 8 It is a partial structural schematic diagram of a back-contact battery in some embodiments. In other embodiments, as Figure 8 shown, the first connection line 4 further includes a sub-connection line 42. The two ends of the sub-connection line 42 are respectively connected to adjacent first pads 31. Exemplarily, as Figure 8 shown, the two ends of the sub-connection line 42 are respectively connected to the adjacent first edge pad 311 and the middle pad 312, that is, the first edge pad 311 and the middle pad 312 are electrically connected through the sub-connection line 42.

[0084] In this embodiment, when the solder strip is separated from the first edge pad 311 and the electrical connection fails, the current on the first fine grid 21 electrically connected to the first edge pad 311 can be transmitted to the solder strip through the first edge pad 311, the sub-connection line 42, and the middle pad 312, thereby reducing the risk that the separation of the first edge pad 311 from the solder strip causes the current on some of the first fine grids 21 to not be collected.

[0085] When the solder strip is electrically connected to the middle pad 312 and fails, the current on the first fine grid 21 electrically connected to the middle pad 312 can be transmitted to the solder strip through the middle pad 312, the sub-connection line 42, and the first edge pad 311, thereby reducing the risk that the separation of the middle pad 312 from the solder strip causes the current on some of the first fine grids 21 to not be collected.

[0086] Therefore, in this embodiment, the first edge pad 311 and the middle pad 312 are electrically connected through the sub-connection line 42, reducing the risk that the electrical connection failure between the first edge pad 311 or the middle pad 312 and the solder strip causes the current on some of the first fine grids 21 to not be collected, which is beneficial to improving the brightness uniformity of the EL test of the back-contact battery and is beneficial to improving the output power and performance of the back-contact battery.

[0087] Figure 8It is illustrated that the adjacent first edge pads 311 and the middle pads 312 are electrically connected through the auxiliary connection lines 42.

[0088] In some embodiments, the adjacent middle pads 312 can also be electrically connected through the auxiliary connection lines 42. Figure 9 It is a partial structural schematic diagram of a back contact battery in some embodiments. As Figure 9 shown, the middle pads 312 at least include a first middle pad 312A, a second middle pad 312B, and a third middle pad 312C arranged along the second direction Y. The auxiliary connection lines 42 at least include 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 part of the second grid lines 222 and the first segment 421 are arranged along the first direction, and a part of the second grid lines 222 and the second segment 422 are arranged along the first direction.

[0089] In this embodiment, the adjacent middle pads 312 are electrically connected through the auxiliary connection lines 42, reducing the risk that the electrical connection failure between the middle pads 312 and the solder tape causes the current on some of the first fine grids 21 to be unable to be collected, which is beneficial to improving the brightness uniformity of the EL test of the back contact battery and is beneficial to improving the output power and performance of the back contact battery.

[0090] As Figure 9 shown, in the first direction X, the width of the main connection line 41 is greater than the width of the auxiliary connection line 42.

[0091] In this embodiment, the main connection line 41 needs to transfer the current of multiple first fine grids 21. Therefore, the width of the main connection line 41 is greater than the width of the auxiliary 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.

[0092] The number of the uninterrupted first grid lines 221 in the second direction Y can be one or multiple. When the number of the first grid lines 221 in the second direction Y is multiple, the above-mentioned L2 is the total length of the second grid lines 222 between two adjacent first grid lines 221, and the above-mentioned L1 is the length of one of the first grid lines 221 in the first direction X.

[0093] The first grid lines 221 and the second grid lines 222 can be periodically arranged in the second direction Y. The specific arrangement form of the first grid lines 221 and the second grid lines 222 in this embodiment of the present application is not particularly limited.

[0094] When the number of the first grid lines 221 in the second direction Y is multiple, Figure 10Schematic diagram of a partial structure of a back contact battery in some embodiments, as Figure 10 shown, a plurality of first grid lines 221 are arranged at intervals in the second direction, and a plurality of middle pads 312 are arranged between two adjacent first grid lines 221.

[0095] In this embodiment, a plurality of first grid lines 221 are arranged in the second direction Y. The current of a part of the interrupted second grid lines 222 can be transmitted through one first grid line 221, and the current of another part 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, so as to facilitate reducing the current transmission capacity required for a single first grid line 221, and thus the width and length of a single first grid line 221 can be adaptively reduced. On 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.

[0096] In some embodiments, a plurality of first grid lines 221 arranged along the second direction Y are all connected to the same edge grid line 5.

[0097] In some other embodiments, as Figure 10 shown, 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 first edge pad 311 are distributed in the first direction X, the second edge grid line 52 and some middle pads 312 are distributed in the first direction X, and the first edge grid line 51 and the second edge grid line 52 are distributed in the second direction Y.

[0098] In this embodiment, a part of the first grid lines 221 are electrically connected to the first edge grid line 51, and a part of the first grid lines 221 are electrically connected to the second edge grid line 52, which can optimize the current distribution on the back contact battery, is beneficial to reducing the loss in the current transmission process, and improving the output power of the back contact battery.

[0099] At the same time, referring to Figure 9 and Figure 10 , in the first direction X, the width of the first edge grid line 51 is H1, the width of the second edge grid line 52 is H2, and H2 < H1, that is, the width of the first edge grid line 51 is greater than the width of the second edge grid line 52.

[0100] In this embodiment, Figure 9 and Figure 10 illustrate that a part of the first edge grid line 51 is located at the chamfer of the body 1, and the first edge grid line 51 is widened, which can improve the current transmission capacity of the first edge grid line 51, thereby improving the current collection efficiency at the edge of the back contact battery, reducing the problem that the edge of the back contact battery is darker and blacker during the EL test, so as to improve the brightness uniformity of the EL test of the back contact battery and improve the output power of the back contact battery.

[0101] In some embodiments, the first edge gate line 51 is disconnected from the second edge gate line 52, that is, current transmission does not occur between the first edge gate line 51 and the second edge gate line 52.

[0102] In other embodiments, with reference to Figure 9 and Figure 10 , the first edge gate line 51 is electrically connected to the second edge gate line 52, that is, current can be transmitted between the first edge gate line 51 and the second edge gate line 52 to optimize the current transmission path, which is beneficial to reducing the loss of current transmission and further improving the output power of the back-contact battery.

[0103] With reference 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 denoted as the above-mentioned first pad 31 to shorten the current transmission path between the second gate line 222 and the edge gate line 5, thereby reducing the current transmission loss.

[0104] Figure 11 FIG. is a schematic diagram of a partial structure of a back-contact battery in some embodiments. As Figure 11 shown, the back-contact battery further 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 gate line 5. The second pad 32 is electrically connected to the second fine gate 22 and insulated from the first fine gate 21. A plurality of second pads 32 are arranged along the second direction Y.

[0105] As Figure 11 shown, the second fine gate 22 further includes a third gate line 223. In the first direction X, both sides of a part of the second pads 32 are respectively connected to the first gate line 221 and the third gate line 223.

[0106] As Figure 11 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.

[0107] 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 ability of the first gate line 221 to facilitate improving the output power of the back-contact battery.

[0108] As Figure 11As shown, the second pad 32 includes a second edge pad 321 located on the outermost side in the second direction Y, and 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 toward the direction close to the edge of the main body 1, that is, the second connecting line 6 and the main connecting line 41 are arranged along the first direction X.

[0109] 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 toward the direction close to the second connection line 6 and leaves a gap with 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.

[0110] In this embodiment, the second fine grid 22 is electrically connected to the second connecting line 6 between the second edge pad 321 and the edge of the main body 1, so that the current on the second fine grid 22 between the second edge pad 321 and the edge of the main body 1 can be transmitted to the welding strip through the second connecting line 6 and the second edge pad 321, thereby reducing the risk of the current on the second fine grid 22 between the second edge pad 321 and the edge of the main body 1 not being collected, thereby improving the brightness uniformity of the EL test of the back-contact battery and the output power of the back-contact battery.

[0111] like Figure 11 As shown, the back contact battery further includes a third connection line 7. In the second direction Y, two ends of the third connection line 7 are electrically connected to adjacent second pads 32 respectively.

[0112] In this embodiment, adjacent second pads 32 are electrically connected via a third connecting line 7, which reduces the risk of failure of the electrical connection between the second pad 32 and the solder strip resulting in the inability to collect current on part of the second fine grid 22, which is beneficial to improving the brightness uniformity of the EL test of the back-contact battery, and is beneficial to improving the output power and performance of the back-contact battery.

[0113] Figure 12 FIG. 1 is a schematic diagram of the partial structure of a back contact battery in some embodiments. 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 alternately arranged in the first direction X. The third pad 33 is electrically connected to the first fine grid 21, and the third pad 33 is insulated from the second fine grid 22. Multiple third pads 33 are arranged along the second direction Y.

[0114] like Figure 12As shown, the third pad 33 includes a third edge pad 331 located on the outermost side in the second direction Y. The back-contact battery further includes a fourth connection line 8. One end of the fourth connection line 8 is electrically connected to the third edge pad 331, and the other end extends in the direction close to the edge of the body 1. That is, the second connection line 6 and the fourth connection line 8 are arranged along the first direction X.

[0115] As Figure 12 shown, there are a first fine grid 21 and a second fine grid 22 between the second connection line 6 and the fourth connection line 8. One end of the second fine grid 22 is connected to the second connection line 6, and the other end extends in the direction close to the fourth connection line 8 and has a gap with the fourth connection line 8, so that the second fine grid 22 is insulated from the fourth connection line 8. A part of the first fine grid 21 is electrically connected to the third edge pad 331, and a part of the first fine grid 21 is electrically connected to the fourth connection line 8 and insulated from the second connection line 6.

[0116] In this embodiment, between the third edge pad 331 and the edge of the body 1, the first fine grid 21 is electrically connected to the fourth connection line 8, so that the current on the first fine grid 21 between the third edge pad 331 and the edge of the body 1 can be transmitted to the solder tape through the fourth connection line 8 and the third edge pad 331, reducing the risk that the current on the first fine grid 21 between 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.

[0117] As Figure 12 shown, the back-contact battery further includes a fifth connection line 9. In the second direction Y, both ends of the fifth connection line 9 are electrically connected to adjacent third pads 33.

[0118] In this embodiment, adjacent third pads 33 are electrically connected through the fifth connection line 9, reducing the risk that the electrical connection between the third pad 33 and the solder tape fails and the current on a part of the first fine grid 21 cannot be collected, which is beneficial to improving the brightness uniformity of the EL test of the back-contact battery and is beneficial to improving the output power and performance of the back-contact battery.

[0119] The second aspect of the embodiments of the present application provides a back-contact stacked battery. Figure 13 It is a schematic diagram of the stacked structure of the back-contact stacked battery provided by the present application in some embodiments. As Figure 13 shown, the back-contact stacked battery 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 is electrically connected to the light-facing surface of the back-contact bottom cell 301, and the back-contact bottom cell 301 is configured as the above-mentioned back-contact battery.

[0120] The perovskite top cell 302 is a thin-film solar cell with a perovskite material as the photoactive layer. The structure of the perovskite top 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 cell 302 to effectively absorb sunlight and convert it into electrical energy. The perovskite material in the perovskite light-absorbing layer has excellent light absorption properties, can absorb a wider spectral range, and effectively convert short-wavelength spectra, making the perovskite top cell 302 have a high photoelectric conversion efficiency.

[0121] The third aspect of the embodiments of the present application provides a photovoltaic module. Figure 14 As shown in the structural schematic diagram of the photovoltaic module provided by the present application in some embodiments, Figure 14 the photovoltaic module includes a cover plate 10, an encapsulation layer 20, and a cell layer 30.

[0122] 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 cell layer 30 are located between the first cover plate 101 and the second cover plate 102, and a part of the encapsulation layer 20 is located between the cell layer 30 and the first cover plate 101, and another part of the encapsulation layer 20 is located between the cell layer 30 and the second cover plate 102 to achieve the encapsulation and fixation of the cover plate 10 and the cell layer 30.

[0123] At least one of the first cover plate 101 and the second cover plate 102 is made of a light-transmissive material, which is beneficial to improving the photoelectric conversion efficiency of the photovoltaic module.

[0124] The material of the first cover plate 101 can be one of rigid materials such as tempered glass, PET (Polyethylene Terephthalate), and PC (Polycarbonate). Alternatively, the material of the first cover plate 101 can be one of flexible materials such as PVF (Polyvinyl Fluoride), ETFE (Ethylene-Tetra-Fluoro-Ethylene copolymer), and PVDF (Polyvinylidene Fluoride). These materials all have a high light transmittance, can ensure that more light irradiates on the cell layer, thereby increasing the light absorption of the photovoltaic module and improving the photoelectric conversion efficiency of the photovoltaic module.

[0125] The material of the second cover plate 102 can be one of rigid materials such as tempered glass, PET (Polyethylene Terephthalate), PC (Polycarbonate), etc. Alternatively, the material of the second cover plate 102 can be one of flexible materials such as PVF (Polyvinyl Fluoride), ETFE (Ethylene-Tetra-Fluoro-Ethylene), PVDF (Polyvinylidene Fluoride), etc.

[0126] The materials of the first cover plate 101 and the second cover plate 102 can be the same or different.

[0127] As Figure 14 shown, the encapsulation layer 20 includes a first adhesive film 201 and a second adhesive film 202. In the third direction Z, a part of the structure of the first adhesive film 201 is located between the battery layer 30 and the first cover plate 101, and a part of the structure of the second adhesive film 202 is located between the battery layer and the second cover plate 102.

[0128] The material of the first adhesive film 201 is one of polyolefins such as EVA (Ethylene-Vinyl Acetate Copolymer), POE (Polyolefin Elastomer), PVB (Polyvinyl Butyral), etc. The above several materials have high light transmittance, which is beneficial to improving the photoelectric conversion efficiency of the photovoltaic module. The first adhesive film 201 can also be an EPE adhesive film (EVA-POE-EVA co-extruded structure) or an EP adhesive film (EVA-POE co-extruded structure).

[0129] The material of the second adhesive film 202 is one of polyolefins such as EVA (Ethylene-Vinyl Acetate Copolymer), POE (Polyolefin Elastomer), PVB (Polyvinyl Butyral), etc. The second adhesive film 202 can also be an EPE adhesive film (EVA-POE-EVA co-extruded structure) or an EP adhesive film (EVA-POE co-extruded structure).

[0130] The materials of the first adhesive film 201 and the second adhesive film 202 can be the same or different.

[0131] The battery layer 30 includes multiple battery strings connected in series or in parallel. Each battery string is formed by connecting multiple solar cells (including but not limited to monocrystalline silicon solar cells and polycrystalline silicon solar cells) in series, and adjacent solar cells are connected by a solder ribbon.

[0132] Figure 15 For Figure 14 the structural schematic diagram of the battery layer 30 in some embodiments. As Figure 15 shown, the battery layer 30 includes multiple solar cells 307, and a solder ribbon 308 is fixed on the solar cell 307, that is, the solder ribbon 308 is welded and fixed to the pads on the solar cell 307. The solder ribbon 308 is used to electrically connect adjacent solar cells 307 to form a battery string. The solar cell 307 further includes a bus bar 309. Along the second direction Y, the bus bar 309 is located on both sides of the battery string and is used to realize the series or parallel connection between multiple battery strings.

[0133] The solar cell 307 can be the above-mentioned back-contact solar cell or the above-mentioned back-contact tandem solar cell 303.

[0134] The battery layer 30 can only include the above-mentioned back-contact solar cells, or only include the above-mentioned back-contact tandem solar cells 303, or can also include both the above-mentioned back-contact solar cells and the above-mentioned back-contact tandem solar cells 303. The embodiments of the present application do not make special limitations on the number, type, series-parallel connection method, etc. of the solar cells included in the battery layer 30. The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. 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, The back-contact battery includes: a body (1); fine grids extending along a first direction (X), the fine grids including first fine grids (21) and second fine grids (22) alternately arranged at intervals along a second direction (Y); a first pad (31), the first pad (31) being electrically connected to the first fine grids (21) and insulated from the second fine grids (22); a first connecting line (4), the first connecting line (4) being electrically connected to the first pad (31); the second fine grids (22) include a first grid line (221) and a plurality of second grid lines (222), the first grid line (221) and the second grid lines (222) are both 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 grid lines (5), in the first direction (X), the fine grids are located on one side of the edge grid lines (5), and the first grid line (221) and the second grid lines (222) are both electrically connected to the edge grid lines (5); in the first direction (X), the length of the first grid line (221) is L1, the sum of the lengths of the plurality of second grid lines (222) is L2, and L2 ≤ L1.

2. The back-contact battery according to claim 1, characterized in that, The plurality of first pads (31) are arranged in the second direction (Y), and the first pads (31) include 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), and the main connecting line (41) is electrically connected to the first edge pads (311).

3. The back-contact battery according to claim 2, wherein, The first pad (31) further includes middle pads (312), and in the second direction (Y), the middle pads (312) are located on one side of the first edge pads (311); in the second direction (Y), at least one of the middle pads (312) is provided between the first edge pads (311) and the first grid line (221).

4. The back contact battery according to claim 2, wherein, The first pad (31) further includes middle pads (312), and in the second direction (Y), the middle pads (312) are located on one side of the first edge pads (311); the middle pads (312) at least include first middle pads (312A), second middle pads (312B), and third middle pads (312C) arranged along the second direction (Y); the first connecting line (4) further includes auxiliary connecting lines (42), the auxiliary connecting lines (42) at least include a first section (421) and a second section (422), two ends of the first section (421) are respectively electrically connected to the first middle pads (312A) and the second middle pads (312B), and two ends of the second section (422) are respectively electrically connected to the second middle pads (312B) and the third middle pads (312C); A part of the second gate line (222) is arranged along the first direction (X) with the first section (421), and a part of the second gate line (222) is arranged along the first direction (X) with the second section (422).

5. The back-contact battery according to claim 4, wherein, In the first direction (X), the width of the main connection line (41) is greater than the width of the sub-connection line (42).

6. The back contact battery according to claim 4, characterized in that, A plurality of the first gate lines (221) are arranged at intervals along the second direction (Y), and a plurality of the middle pads (312) are arranged between two adjacent first gate lines (221).

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

8. The back-contact battery according to claim 7, wherein, 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, 1 ≤ L1 / L2 ≤ 1.

5.

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

11. 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 line (22) electrically connected to the edge gate line (5) is H2, where H2 < H1.

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

13. The back-contact battery according to any one of claims 1 to 8, characterized in that, The back-contact battery further includes a second pad (32). In a first direction (X), the second pad (32) is located on a 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 the second pad (32) is insulated from the first fine grid (21). A plurality of the second pads (32) are arranged along a second direction (Y). The back-contact battery further includes a third connection line (7). In the second direction (Y), two ends of the third connection line (7) are respectively electrically connected to adjacent second pads (32).

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

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

Images