Electrode structure of a back contact cell, back contact cell and photovoltaic module
By setting alternating current-collecting grid lines and edge current-collecting or conductive grid lines on the back of the back-contact battery, the leakage and short-circuit problems caused by the metal grid lines at the edge of the battery during the electroplating process are solved, simplifying the process steps, reducing production costs and improving yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TONGWEI SOLAR ENERGY (CHENGDU) CO LID
- Filing Date
- 2025-06-20
- Publication Date
- 2026-06-23
AI Technical Summary
During the electroplating process, metal grid lines are prone to appear on the edges of existing back-contact batteries, leading to defects such as leakage and short circuits. Furthermore, the existing edge-wrapping process increases production costs and complexity.
Alternating first and second current collector grid lines are provided on the back side of the back contact battery, and current collector or conductive grid lines are provided at the edge to connect areas of the same polarity, simplifying the electroplating process and eliminating the edge wrapping process.
It achieves the convenience of electroplating conductivity, simplifies process steps, reduces production costs, improves process yield, and reduces equipment investment and ink consumption.
Smart Images
Figure CN224402016U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of photovoltaic technology, and more specifically, to an electrode structure for a back contact battery, a back contact battery, and a photovoltaic module. Background Technology
[0002] Currently, back contact (BC) batteries have adopted electroplating electrode technology to reduce costs. However, due to the PVD sputtering of the metal seed layer, metal is also sputtered onto the edge of the silicon wafer during the patterned electroplating process. Screen printing technology cannot print the mask ink onto the edge of the battery for cross-sectional protection. After electroplating the metal grid lines, there will be a ring of metal grid lines on the edge of the battery, which can easily lead to defects such as leakage and short circuits during the module manufacturing process.
[0003] Existing technologies mostly use edge-binding technology for battery edges, which also has the following problems: (1) The added edge-binding process increases production costs; (2) The battery cell production process becomes longer, introducing more process anomalies and reducing battery production yield; (3) The graphic ink mask printing that matches the edge-binding process is printed in the non-electrode area, which makes graphic alignment difficult, printing area large, and ink consumption high.
[0004] Therefore, this application is submitted. Utility Model Content
[0005] The purpose of this invention is to provide an electrode structure for a back contact battery, a back contact battery, and a photovoltaic module. This electrode structure facilitates electroplating for conductivity and simplifies the process steps.
[0006] The embodiments of this utility model can be implemented as follows:
[0007] In a first aspect, the present invention provides an electrode structure for a back contact battery, wherein a plurality of first current collector grid lines and a plurality of second current collector grid lines are provided on the back side of the back contact battery, the first current collector grid lines and the second current collector grid lines are alternately arranged, the first current collector grid lines and the second current collector grid lines are both spaced apart along a first direction and extend along a second direction that intersects the first direction;
[0008] When the back of the battery is also provided with a plurality of first busbars and a plurality of second busbars, both the first busbars and the second busbars extend along a first direction and are spaced apart along a second direction. Each first busbar is connected to a first current collector with the same polarity, and each second busbar is connected to a second current collector with the same polarity. At the edge, a first edge busbar and a second edge busbar are also provided. The first edge busbar is connected to a first busbar with the same polarity, and the second edge busbar is connected to a second busbar with the same polarity.
[0009] When the back contact battery does not have a first busbar and a second busbar, a first conductive grid and a second conductive grid are provided at the edge. The first conductive grid is connected to the first current collector grid of the same polarity, and the second conductive grid is connected to the second current collector grid of the same polarity.
[0010] In an optional implementation, the first edge busbar is located at one end, and the second edge busbar is located at the opposite end in the same direction.
[0011] In an optional embodiment, the first conductive gate line is located at one end, and the second conductive gate line is located at the opposite end in the same direction.
[0012] In an optional embodiment, a main gate and a sub-gate having a first polarity constitute a first polarity region, and a main gate and a sub-gate having a second polarity constitute a second polarity region, with a first partition region provided between the first polarity region and the second polarity region.
[0013] In an optional embodiment, a second partition area is provided at the edge of the back side of the battery.
[0014] In an optional implementation, when the back contact battery has a first busbar and a second busbar, the following is defined: the length of the first edge busbar or the second edge busbar is L, the length of the connection between the outermost two main gate carrier functional transport layers is L1, and the length of the connection between the outermost two main gate carrier functional transport layers of the same polarity is L2; L, L1, and L2 satisfy: L2≤L≤L1;
[0015] When the back of the back contact battery does not have a first busbar and a second busbar, the following is defined: the length of the outermost sub-gate is l, the length of the connection between the outermost two main gates of the carrier functional transmission layer is l1, and the length of the connection between the outermost two same polarity carrier functional transmission layers of the same line is l2; l, l1 and l2 satisfy: l2≤l≤l1.
[0016] In an optional implementation, when the back contact battery is provided with a first busbar and a second busbar, the width of the outermost first edge busbar or the second edge busbar is defined as W1, and the width of the other inner same-pole sub-gates is W2. W1 and W2 satisfy: W2≤W1≤10W2.
[0017] When the back of the battery does not have a first busbar and a second busbar, the following is defined: the width of the outermost sub-gate is w1, and the width of the other inner sub-gates of the same pole is w2. w1 and w2 satisfy: w2≤w1≤10w2.
[0018] In an optional implementation, when the first busbar and the second busbar are provided on the back side of the back contact battery, the following is defined: the width of the outermost main grid is W3, the width of the inner same-pole main grid is W4, and W3 and W4 satisfy: W4≤W3≤10W4;
[0019] When the back of the back contact battery does not have a first busbar and a second busbar, the following is defined: the width of the first or second conductive busbar is w3, the width of the inner same-pole sub-busbar is w2, and w3 and w2 satisfy: w2≤w3≤10w2.
[0020] Secondly, this utility model provides a back contact battery, including the electrode structure of any of the back contact batteries described in the foregoing embodiments.
[0021] Thirdly, this utility model provides a photovoltaic module, including the back contact battery described in the foregoing embodiments.
[0022] The beneficial effects of the electrode structure, back-contact battery, and photovoltaic module provided by this utility model embodiment include: by adjusting the grid pattern, for SMBB (Super Many Grids) batteries, a first edge busbar and a second edge busbar are set at the edge to connect the same polarity grid; for OBB (Obstacle-free) batteries, a first conductive grid and a second conductive grid are set at the edge to connect the same polarity sub-grid. The improved electrode structure allows for conductivity within the same polarity region, facilitating electroplating conductivity. Using the electrode structure provided by this utility model, the current process sequence can be changed, and battery fabrication can be completed without the edge-wrapping process. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a first structural schematic diagram of the electrode structure of the back contact battery provided in this embodiment;
[0025] Figure 2 This is a second structural schematic diagram of the electrode structure of the back contact battery provided in this embodiment;
[0026] Figure 3 for Figure 1 Dimensioning diagram of the center grid line;
[0027] Figure 4 for Figure 2 Dimensioning diagram of the center grid line;
[0028] Figure 5 A comparison diagram of the preparation process and existing processes provided for embodiments of this utility model;
[0029] Figure 6 A schematic diagram of the first cross-section of an un-surrounded battery after the passivation layer has been prepared;
[0030] Figure 7 A schematic diagram of the first-direction cross-section of an unenclosed battery with a laser-cut opening;
[0031] Figure 8 A schematic diagram of the first cross-section of an un-edged battery with a deposited conductive seed layer;
[0032] Figure 9 A schematic diagram of the first cross-section of an un-enclosed solar cell used to fabricate an etch-resistant mask;
[0033] Figure 10 A schematic diagram of the first cross-section of an unwrapped battery with a back-etched film removal process;
[0034] Figure 11 This is a schematic diagram of the first cross-section of an un-enclosed battery with electroplated electrodes.
[0035] Icons: 111 - First collector grid line; 112 - Second collector grid line; 113 - First bus grid line; 114 - Second bus grid line; 115 - First edge bus grid line; 116 - Second edge bus grid line; 117 - First conductive grid line; 118 - Second conductive grid line; 001 - First polarity region; 002 - Second polarity region; 003 - First isolation region; 004 - Second isolation region;
[0036] 201-First polar carrier functional transport layer; 202-Second polar carrier functional transport layer; 203-Silicon substrate; 204-Passivation layer; 205-Opening; 206-Seed layer; 207-Seed layer etch-resistant mask; 208-First polar electrode; 209-Second polar electrode. Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0040] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0041] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.
[0042] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.
[0043] In addition, for ease of understanding, the technical terms involved in the embodiments of this utility model are explained in detail in the table below:
[0044] like Figure 1 and Figure 2 As shown, this utility model embodiment provides an electrode structure for a back contact battery. A plurality of first current collector grid lines 111 and a plurality of second current collector grid lines 112 are provided on the back side of the back contact battery. The first current collector grid lines 111 and the second current collector grid lines 112 are alternately arranged. The first current collector grid lines 111 and the second current collector grid lines 112 are both spaced apart along a first direction and extend along a second direction that intersects the first direction.
[0045] Specifically, the number of the first current collector 111 and the second current collector 112 is not limited; for example, there can be two or more, and the number of both can be the same. The methods and materials used to prepare the first current collector 111 and the second current collector 112 are not limited; existing methods and materials for preparing secondary current collectors are all within the scope of protection of this utility model. The first direction and the second direction can be perpendicular, but are not limited to this.
[0046] This invention connects the same-polarity grid lines on the outermost ring of the battery and sets the electroplating points on the outermost electrodes, thus connecting the originally segmented same-polarity electrodes in series. This solution can be used for SMBB batteries as well as OBB batteries. Figure 1 , Figure 2 As shown.
[0047] Figure 1 This diagram shows the electrode structure on the back of an SMBB battery. When the back of this type of battery also has multiple first busbars 113 and multiple second busbars 114, both the first busbars 113 and the second busbars 114 extend along a first direction and are spaced apart along a second direction. Each first busbar 113 is connected to a first current collector 111 of the same polarity, and each second busbar 114 is connected to a second current collector 112 of the same polarity. At the edges, first edge busbars 115 and second edge busbars 116 are also provided. The first edge busbars 115 are connected to the first busbars 113 of the same polarity, and the second edge busbars 116 are connected to the second busbars 114 of the same polarity. By connecting the first edge busbars 115 and the second edge busbars 116 to the main grid of the same polarity, the same polarity region can be continuously conductive, facilitating electroplating conductivity, because vertical electroplating can only achieve conductivity by setting clamps at fixed positions. By adjusting the grid pattern, the order of the current processes can be changed, and the battery can be manufactured without using the edge-wrapping process.
[0048] Specifically, the number of the first busbar 113 and the second busbar 114 is not limited; for example, there can be two or more, and the number of both can be the same. The methods and materials used to prepare the first busbar 113 and the second busbar 114 are not limited; existing methods and materials for preparing the main busbar are all within the scope of protection of this utility model. The first direction and the second direction can be perpendicular, but are not limited to this. The alternating arrangement of the first busbar 113 and the second busbar 114 means that both sides of the first busbar 113 are occupied by the second busbar 114, and both sides of the second busbar 114 are occupied by the first busbar 113.
[0049] Furthermore, the first edge busbar 115 is located at one end, and the second edge busbar 116 is located at the opposite end in the same direction. That is to say, in the same direction of the SMBB battery, the outermost sides of both sides need to have the first polarity electrode main / sub grid and the second polarity electrode main / sub grid distributed respectively. The outermost sides cannot have the same polarity electrode distributed, that is, the first polarity electrode is distributed at the top, and the second polarity electrode needs to be distributed at the bottom, and the same applies to the left and right sides.
[0050] Figure 2For 0BB batteries, the first busbar 113 and the second busbar 114 are not provided on the back of the battery. Instead, the first conductive grid 117 and the second conductive grid 118 are provided on the edge. The first conductive grid 117 is connected to the first current collector 111 of the same polarity, and the second conductive grid 118 is connected to the second current collector 112 of the same polarity, so that the same polarity area can be conductive and facilitate electroplating conductivity.
[0051] Furthermore, the first conductive grid line 117 is located at one end, and the second conductive grid line 118 is located at the opposite end in the same direction. That is, the first conductive grid line 117 and the second conductive grid line 118 are located at opposite ends, and can be adjusted according to the position of the sub-grid. Specifically, conductive main grids of different polarities in the OBB battery must exist simultaneously, and each is distributed at both ends of the sub-grid.
[0052] like Figure 1 and Figure 2 As shown, a main gate and a sub-gate with a first polarity constitute a first polarity region 001, and a main gate and a sub-gate with a second polarity constitute a second polarity region 002. A first partition region 003 is provided between the first polarity region 001 and the second polarity region 002 to separate the two polarity regions. A second partition region 004 is provided at the edge of the back side of the battery.
[0053] The length of the main grid in an SMBB / OBB battery is determined by the width and number of sub-grids, and the main grid needs to connect to the two outermost sub-grids. This invention also optimizes the dimensions of the main grid or sub-grids to improve carrier transport efficiency.
[0054] like Figure 3 As shown, when the back contact battery has a first busbar 113 and a second busbar 114 on its back side, i.e., an SMBB battery, the following is defined: the length of the first edge busbar 115 or the second edge busbar 116 is L; the length of the connection between the outermost two main busbars' carrier functional transport layers is L1; and the length of the connection between the outermost two main busbars' carrier functional transport layers of the same polarity is L2. L, L1, and L2 satisfy: L2 ≤ L ≤ L1. That is, the maximum value of L is equal to L1, and the minimum value is equal to L2. If L is too small, it cannot penetrate the main busbar; if L is too long, it will exceed the area it is in and affect the fabrication of busbars in other areas.
[0055] Specifically, "the outer edge of the main gate carrier functional transport layer" refers to the maximum distance between the edge of the main gate carrier functional transport layer in the direction perpendicular to the main gate distribution.
[0056] Furthermore, such as Figure 3As shown, when the back contact battery has a first busbar 113 and a second busbar 114 on its back side, i.e., an SMBB battery, the following is defined: the width of the outermost first edge busbar 115 or the second edge busbar 116 is W1, and the width of the other inner same-pole sub-gates is W2. W1 and W2 satisfy: W2≤W1≤10W2. That is, the width of the outermost first edge busbar 115 or the second edge busbar 116 is greater than or equal to the width of the other inner same-pole sub-gates, and less than or equal to 10 times the width of the other inner same-pole sub-gates. If W1 is less than W2, the carrier collection channel will become smaller, resulting in current loss; at the same time, it will also cause contact difficulties during electroplating, which can easily reduce the process yield. If W1 is greater than 10W2, it is not conducive to improving the effective collection area of photogenerated carriers. By controlling the range of W1 within the range of this application, the carrier collection area can be maximized, while current loss can be avoided, ensuring process yield.
[0057] like Figure 3 As shown, the outermost main gate width is defined as W3, and the innermost main gate width is W4. W3 and W4 satisfy: W4≤W3≤10W4. That is, the outermost main gate width is greater than or equal to the innermost main gate width, and less than or equal to 10 times the innermost main gate width, to improve edge conductivity. The effects of excessively large or small W3 are similar to those of excessively large or small W1, and will not be repeated here.
[0058] like Figure 4 As shown, when the back contact battery does not have a first busbar 113 and a second busbar 114 on its back side, i.e., an OBB battery, the following definitions apply: the length of the outermost sub-gate is l (there is an overlapping area between the main gate and the sub-gate), the length of the line connecting the outer sides of the outermost main gate carrier functional transport layer is l1, and the length of the line connecting the outer sides of the outermost same-polarity carrier functional transport layer is l2; l, l1, and l2 satisfy: l2≤l≤l1. Specifically, "the line connecting the outer sides of the outermost main gate carrier functional transport layer" refers to the maximum distance between the edges of the main gate carrier functional transport layer closest to the battery edge in the direction perpendicular to the main gate distribution; "the line connecting the outer sides of the same-polarity carrier functional transport layer" refers to the maximum distance between the edges of the same-polarity main gate carrier functional transport layer closest to the battery edge in the direction perpendicular to the main gate distribution.
[0059] like Figure 4As shown, when the back of the battery does not have a first busbar 113 and a second busbar 114, i.e., an OBB battery, the following definition applies: the width of the outermost sub-gate is w1, and the width of the other inner same-pole sub-gates is w2, where w1 and w2 satisfy: w2≤w1≤10w2. That is, the width of the outermost sub-gate is greater than or equal to the width of the other inner same-pole sub-gates, and less than or equal to 10 times the width of the other inner same-pole sub-gates. If w1 is less than w2, the carrier collection channel will be smaller, resulting in current loss; it will also cause contact difficulties during electroplating, easily reducing process yield. If w1 is greater than 3w2, it is not conducive to improving the effective collection area of photogenerated carriers. Controlling the range of w1 within the scope of this application can maximize the carrier collection area while avoiding current loss and ensuring process yield. Figure 4 As shown, when the back contact battery does not have a first busbar 113 and a second busbar 114 on its back side, i.e., an OBB battery, the following definition applies: the width of the first conductive grid 117 or the second conductive grid 118 is w3, and the width of the inner same-pole sub-grid is w2. w3 and w2 satisfy: w2≤w3≤10w2. That is, the width of the first conductive grid 117 or the second conductive grid 118 is greater than or equal to the width of the inner same-pole sub-grid, and less than or equal to 10 times the width of the inner same-pole sub-grid. The effects of w3 being too large or too small are similar to those of w1, and will not be repeated here.
[0060] This utility model embodiment also provides a back contact battery, including the electrode structure of the aforementioned back contact battery, and further including other functional layer structures of the battery.
[0061] The back contact battery provided in this embodiment of the invention can be manufactured without using an edge-wrapping process by adjusting the grid pattern and changing the order of the current processes. A comparison of the manufacturing process of the back contact battery with existing processes is provided below. Figure 5 As shown: First, a passivated silicon wafer is prepared; then, laser patterning is performed to create laser windows in the gate line prefabrication area; next, a seed layer is deposited using PVD; then, mask ink is printed on the surface of the PVD film to mask the seed layer of the electrode gate line portion; then, the exposed seed layer is etched back; then, the anti-etching mask layer on the electrode surface is removed; finally, the metal gate line is electroplated to increase the cross-sectional area of the gate line and reduce the resistance.
[0062] It should be noted that, in this embodiment of the invention, by changing the grid pattern of the battery, all electrodes of the same polarity are connected in series; after PVD, etch-resistant ink is directly printed to cover and protect the electrode grid lines; then the excess seed layer is etched to form the basic morphology of the grid lines; then the mask layer is removed to expose the seed layer grid lines; then the P / N region grid lines can be thickened synchronously / stepwise by rack plating to finally form a complete electrode.
[0063] The improved process has the following advantages over the existing process: (1) It reduces the number of steps and equipment investment, thereby reducing production costs; (2) The ink in this scheme does not need to be electroplating resistant, and the ink cost is lower; (3) When screen printing is used for patterning, the printing area of the etching resistant ink is small and the ink wet weight is low, reducing non-silicon costs; (4) The difficulty of aligning the screen printed pattern with the laser pattern is reduced; (5) No additional electroplating hang points are required, reducing the risk of electroplating hang point misalignment and improving process yield; Specifically, the electroplating hang points are set on the outermost main grid and the outermost through sub-grid of the battery. For SMBB batteries, the electroplating hang points can be set only on the outer through sub-grid, and for 0BB batteries, the electroplating hang points can be set only on the outer conductive main grid; (6) The copper surface does not need to be electroplated with an extra metal layer for protection (the current scheme needs to prevent the electrode copper from being corroded during the process of re-etching the seed layer).
[0064] The core of the fabrication process is the electrode fabrication process, applicable to BC solar cells that require electrode fabrication using a plating process. A crucial aspect is cell patterning. Specifically, this invention connects the outermost ring of same-polarity grid lines and sets the plating points on the outermost electrodes, thus connecting the originally segmented same-polarity electrodes in series. The specific electrode fabrication process is as follows:
[0065] Step 1: First, clean and roughly polish the silicon wafer to remove impurities and grooves from the surface of the silicon wafer, making the surface of the silicon wafer smooth.
[0066] Step 2: Perform the first oxidation and doping to prepare the first polar carrier transport functional region, and then perform the first laser patterning to remove the second polar carrier functional transport layer 202 and the first polar carrier transport functional region at the location of the isolation region. In particular, during the first laser patterning process, the outermost part of the first polar carrier functional transport layer 201 is connected, connecting all the first polar carrier functional transport layers 201.
[0067] Step 3: After the first laser patterning, the silicon wafer is cleaned by alkaline polishing, and then subjected to a second oxidation and doping process to prepare the second polar carrier functional transport layer 202. After the preparation is completed, a second laser patterning is performed to create the isolation region, separating the two different polar carrier functional layers. The outermost parts of the second polar carrier functional transport layer 202 are connected, connecting all the second polar carrier functional transport layers 202.
[0068] Step 4: After the partition area is prepared, alkaline polishing and texturing are performed to create a textured surface on the exposed area of the silicon substrate 203. Then, passivation layer 204 is deposited sequentially over the entire area of the silicon wafer to provide passivation protection. Its cross-sectional structure is as follows: Figure 6 As shown.
[0069] Step 5: Use laser / etching to form openings 205 in the area where electrodes need to be fabricated to remove the passivation layer 204, enabling the electrodes to connect to the carrier transport functional layer, such as... Figure 7 As shown.
[0070] Step Six: Deposit a conductive seed layer 206 on the silicon wafer surface of the opening 205, covering the silicon wafer electrode fabrication surface and all cell sides perpendicular to this surface, such as... Figure 8 As shown.
[0071] Step 7: After depositing the seed layer 206, the patterning process begins. A seed layer etch-resistant mask 207 is fabricated in the area where electrodes need to be prepared to protect the seed layer in this area and form the electrode grid pattern, such as... Figure 9 As shown.
[0072] Step 8: First, etch the seed layer in the area not covered by the mask, then remove the mask to prepare a silicon wafer covered with the seed layer gate lines, such as... Figure 10 As shown.
[0073] Step Nine: Finally, the seed layer grid lines are thickened using a plating technique to obtain a solar cell with complete electrodes, including a first polarity electrode 208 and a second polarity electrode 209, as shown below. Figure 11 As shown.
[0074] Thirdly, this utility model provides a photovoltaic module, including the back contact cell described in the foregoing embodiments. It is composed solely of the aforementioned SMBB or OBB cells. The solder ribbon connection direction of the SMBB cell is consistent with the main busbar direction, while the solder ribbon connection direction of the OBB cell can be consistent with either the main busbar direction or the sub-busbar direction.
[0075] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.
Claims
1. An electrode structure of a back contact cell, characterized by, Multiple first current collector lines and multiple second current collector lines are provided on the back side of the back contact battery. The first current collector lines and the second current collector lines are alternately arranged. The first current collector lines and the second current collector lines are spaced apart along a first direction and extend along a second direction that intersects the first direction. When the back of the back contact battery is further provided with a plurality of first busbars and a plurality of second busbars, the first busbars and the second busbars extend along the first direction and are spaced apart along the second direction. Each first busbar is connected to a first current collector with the same polarity, and each second busbar is connected to a second current collector with the same polarity. At the edge, a first edge busbar and a second edge busbar are also provided. The first edge busbar is connected to a first busbar with the same polarity, and the second edge busbar is connected to a second busbar with the same polarity. When the back contact battery does not have a first busbar and a second busbar, a first conductive grid and a second conductive grid are provided at the edge. The first conductive grid is connected to the first current collector grid of the same polarity, and the second conductive grid is connected to the second current collector grid of the same polarity.
2. The electrode structure of a back contact cell according to claim 1, wherein The first edge busbar is located at one end, and the second edge busbar is located at the opposite end in the same direction.
3. The electrode structure of a back contact cell according to claim 1, wherein, The first conductive gate line is located at one end, and the second conductive gate line is located at the opposite end in the same direction.
4. The electrode structure of the back contact battery according to claim 1, characterized in that, A primary gate and a secondary gate with a first polarity constitute a first polarity region, and a primary gate and a secondary gate with a second polarity constitute a second polarity region. A first partition region is provided between the first polarity region and the second polarity region.
5. The electrode structure of the back contact battery according to claim 4, characterized in that, A second partition area is provided at the edge of the back side of the battery.
6. The electrode structure of the back contact battery according to claim 1, characterized in that, When the back contact battery is provided with a first busbar and a second busbar, the following is defined: the length of the first edge busbar or the second edge busbar is L, the length of the connection between the outermost two main gate carrier functional transport layers is L1, and the length of the connection between the outermost two main gate carrier functional transport layers of the same polarity is L2; L, L1 and L2 satisfy: L2≤L≤L1; When the back contact battery does not have a first busbar and a second busbar, the following are defined: the length of the outermost sub-gate is l, the length of the connection between the outermost two main gates of the carrier functional transmission layer is l1, and the length of the connection between the outermost two same polarity carrier functional transmission layers of the main gate is l2; l, l1 and l2 satisfy: l2≤l≤l1.
7. The electrode structure of the back contact battery according to claim 1, characterized in that, When the back contact battery is provided with a first busbar and a second busbar, the following is defined: the width of the outermost first edge busbar or the second edge busbar is W1, and the width of the other inner same-pole sub-gates is W2. W1 and W2 satisfy: W2≤W1≤10W2. When the back of the back contact battery does not have a first busbar and a second busbar, the following is defined: the width of the outermost sub-gate is w1, and the width of the other inner same-pole sub-gates is w2, where w1 and w2 satisfy: w2≤w1≤10w2.
8. The electrode structure of the back contact battery according to claim 1, characterized in that, When the back contact battery is provided with a first busbar and a second busbar, the following is defined: the width of the outermost main grid is W3, the width of the inner same-pole main grid is W4, and W3 and W4 satisfy: W4≤W3≤10W4; When the back of the back contact battery is not provided with the first busbar and the second busbar, the following is defined: the width of the first conductive grid or the second conductive grid is w3, the width of the inner same-pole sub-grid is w2, and w3 and w2 satisfy: w2≤w3≤10w2.
9. A back-contact battery, characterized in that, The electrode structure includes the back contact battery as described in any one of claims 1-8.
10. A photovoltaic module, characterized in that, Includes the back contact battery as described in claim 9.