Back contact type solar cell and photovoltaic module

Abstract

The utility model provides a back contact type solar cell and a photovoltaic assembly, and belongs to the technical field of solar cells. First grid line electrodes and second grid line electrodes are printed on the surface of the back contact type solar cell, and the first grid line electrodes and the second grid line electrodes are arranged in a staggered mode at intervals. Wherein the first grid line electrode and the second grid line electrode are constructed to meet the size relationship shown in the formula (1): rho1 / S1 < = rho2 / S2 < 2rho1 / S1, (1); wherein rho1 is the resistivity of the first grid line electrode, rho2 is the resistivity of the second grid line electrode, S1 is the sectional area of the first grid line electrode, and S2 is the sectional area of the second grid line electrode; and the grid line spacing of the first grid line electrode or the second grid line electrode is 0.25-2mm. According to the utility model, the usage amount of grid line slurry in unit area can be reduced on the basis that the performance of the battery is not lost, so that the abnormal warping caused by the contraction of the grid line is reduced.

Description

Technical Field

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

[0002] Solar cells are one of the important products in the new energy industry and are expected to become an important part of the development of renewable energy in the future. After years of industry iteration, battery technologies have blossomed, such as the mainstream PERC (Passivated Emitter and Rear Cell), N-Topcon (Tunnel Oxide Passivated Contact), HJT (Heterojunction), IBC (Interdigitated Back Contacted) and other batteries on the market.

[0003] IBC cells belong to the back contact cell structure, which means that the emitter and the corresponding P-region electrode and N-region electrode are all located on the back of the cell, and there is no metal grid line on the front, so there is no metal electrode shading. It is a solar cell with relatively high conversion efficiency. By optimizing IBC cells, a variety of cell structures have been derived, such as POLO-IBC (Polycrystalline silicon (poly-Si) 0n Oxide (POLO)-Interdigitated Back Contacted, polycrystalline silicon oxide layer-interdigitated), and HPBC (High Performance Back Contact) cells.

[0004] These back-contact solar cells can use P-region electrodes and N-region electrodes printed on a single side of the cell. After high-temperature sintering, more electrode slurry shrinks, causing the cell to warp abnormally, thereby increasing the risk of cell fragmentation or cracking in subsequent processes. Utility Model Content

[0005] In view of this, the main purpose of the present invention is to provide a back-contact solar cell and photovoltaic module, which can reduce abnormal warping of the battery while maintaining the battery performance.

[0006] In order to achieve the above purpose, the technical solution of the utility model is as follows:

[0007] According to an embodiment of one aspect of the utility model, a back-contact solar cell is provided, wherein a first grid line electrode and a second grid line electrode are printed on the surface of the solar cell, and the first grid line electrode and the second grid line electrode are alternately arranged at intervals;

[0008] The first gate line electrode and the second gate line electrode are configured to satisfy the size relationship shown in formula (1):

[0009] ρ1 / S1≤ρ2 / S2<2ρ1 / S1, (1);

[0010] Wherein, ρ1 is the resistivity of the first gate line electrode, ρ2 is the resistivity of the second gate line electrode, S1 is the cross-sectional area of ​​the first gate line electrode, and S2 is the cross-sectional area of ​​the second gate line electrode;

[0011] Furthermore, a gate line spacing between the first gate line electrode or the second gate line electrode is 0.25-2 mm.

[0012] According to an embodiment of the utility model, the first gate line electrode is a P region gate line, and the second gate line electrode is an N region gate line; wherein the cross-sectional height of the first gate line electrode is 10 to 30 μm, and the cross-sectional width of the first gate line electrode is 90 to 150 μm; the cross-sectional height of the second gate line electrode is 5 to 15 μm, and the cross-sectional width of the second gate line electrode is 25 to 50 μm.

[0013] According to an embodiment of the present utility model, the grid line spacing of the first grid line electrode or the second grid line electrode is 0.25-1 mm.

[0014] According to an embodiment of the present invention, the cross-sectional area of ​​the first gate line electrode is 90 to 1300 μm 2 , 90~1300μm of the second gate electrode 2 .

[0015] According to an embodiment of the present invention, the resistivity of the first gate line electrode and the resistivity of the second gate line electrode are 1*10 -8 Ω·m~5*10 -8 Ω·m.

[0016] According to an embodiment of the present invention, the first gate line electrode and the second gate line electrode are respectively selected from aluminum, silver or copper.

[0017] According to an embodiment of the present utility model, the cross-sections of the first gate line electrode and the second gate line electrode are quasi-triangular.

[0018] According to an embodiment of the utility model, the back-contact solar cell includes a first doping region and a second doping region, which are alternately arranged to form an interdigitated structure; wherein the first gate electrode is formed on the first doping region, and the second gate electrode is formed on the second doping region.

[0019] According to an embodiment of the utility model, a first main grid electrode and a second main grid electrode are also printed on the surface of the back-contact solar cell; wherein the first grid line electrode is connected to the first main grid electrode, and the second grid line electrode is connected to the second main grid electrode.

[0020] According to another embodiment of the present invention, a photovoltaic assembly is provided, comprising the above-mentioned back-contact solar cell; wherein two adjacent back-contact solar cells are connected by a welding ribbon.

[0021] According to the embodiments of the present invention, the cross-sectional area and the gate line spacing of the gate line electrodes are optimized based on the conductive characteristics of the gate line electrodes. The amount of gate line slurry per unit area can be reduced without sacrificing battery performance, thereby reducing the warping anomaly caused by gate line shrinkage.

[0022] According to the embodiments of the utility model, when a photovoltaic module is manufactured based on the above-mentioned back-contact solar cells, the abnormal warping of the back-contact solar cells is improved, so that when the photovoltaic modules are subsequently manufactured through processes such as battery welding and packaging, the risk of fragmentation and cracking can be reduced, thereby reducing the abnormality rate of the photovoltaic module manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the electrode structure on the back side of the back-contact solar cell of the utility model;

[0024] Figure 2 for Figure 1 A partial enlarged view of the area selected in the middle box;

[0025] Figure 3 A schematic top view of a back-contact solar cell according to an embodiment of the utility model;

[0026] Figure 4 A schematic side view of a back-contact solar cell according to an embodiment of the present utility model;

[0027] Figure 5 For the embodiment of the utility model relative to Figure 4 Schematic diagram of reducing the amount of electrode slurry after reducing the grid line spacing. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the utility model. The terms "including", "comprising", etc. used herein indicate the presence of features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components. All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used here should be interpreted as having meanings consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0030] In the process of realizing the concept of the utility model, it was found that for back-contact batteries, the printing method of the gate electrode can be screen printing or inkjet printing. After the electrode slurry is printed on the surface of the battery, it needs to be sintered. At this time, the organic components of the electrode slurry volatilize, and the inorganic components and metal powder melt and then solidify, which will cause the electrode slurry to produce a shrinkage force.

[0031] Since a large amount of electrode slurry is printed on the surface of the battery, after the sintering process, the shrinkage of a large amount of electrode slurry will easily cause the battery to be abnormally warped, which will increase the risk of fragmentation and cracking in subsequent processes such as welding and packaging. Therefore, the utility model proposes a back-contact solar cell and photovoltaic module. Based on the printing characteristics of the grid line electrode, the optimization of the grid line size can be achieved through graphic optimization and printing specification adjustment. Thereby, the amount of grid line slurry per unit area can be reduced without losing the battery performance, and the warping abnormality caused by shrinkage can be reduced. Therefore, the abnormality rate of the photovoltaic module using the back-contact solar cell of the utility model in the production process is also reduced.

[0032] Specifically, according to an embodiment of the present invention, a back-contact solar cell is provided. Figure 1 It is a schematic diagram of the electrode structure on the back side of the back-contact solar cell of the utility model; Figure 2 for Figure 1 A partial enlarged view of the selected area.

[0033] like Figure 1 and Figure 2 The back-contact solar cell 100 of the present utility model is shown, wherein the surface of the solar cell is printed with a first gate electrode 101 and a second gate electrode 102, and the first gate electrode 101 and the second gate electrode 102 are arranged alternately; wherein the first gate electrode 101 and the second gate electrode 102 are configured to satisfy the size relationship shown in formula (1):

[0034] ρ1 / S1≤ρ2 / S2<2ρ1 / S1, (1);

[0035] Wherein, ρ1 is the resistivity of the first gate line electrode 101, ρ2 is the resistivity of the second gate line electrode 102, S1 is the cross-sectional area of ​​the first gate line electrode 101, S2 is the cross-sectional area of ​​the second gate line electrode 102; and the gate line spacing of the first gate line electrode 101 or the second gate line electrode 102 is 0.25-2 mm.

[0036] According to the embodiment of the utility model, for the back-contact solar cell, the "surface" printed with the first grid line electrode 101 and the second grid line electrode 102 is the back side of the back-contact solar cell, or called the backlight side; and the front side of the back-contact solar cell is the light-receiving side. Since there is no electrode blocking the front side, the battery efficiency is higher.

[0037] According to the embodiment of the utility model, the "cross-sectional area" of the first gate line electrode 101 or the second gate line electrode 102 has its inherent meaning in the art, which is the area of ​​the cross section perpendicular to the electrode extension direction, that is, the length direction. The "gate line spacing" has its inherent meaning in the art, which is the spacing between adjacent first gate line electrodes 101 or between adjacent second gate line electrodes 102.

[0038] According to an embodiment of the utility model, in a back-contact solar cell, the first gridline electrode and the second gridline electrode are basically distributed in equal proportion, that is, the extension length L1 of the first gridline electrode and the extension length L2 of the second gridline electrode are equal, so that on the basis of satisfying the relationship shown in the above formula (1), the line resistance R1 of the first gridline electrode and the line resistance R2 of the second gridline electrode are relatively matched, so that the battery performance reaches a better state, wherein R1 can be expressed as (ρ1*L1) / S1, and R2 can be expressed as (ρ2*L2) / S2. Among them, R1=R2 is a relatively ideal state, which can help to achieve better battery performance.

[0039] At the same time, when the pitch of the first gate electrode or the second gate electrode is within 0.25-2 mm, the collection effect of battery carriers will be improved, so the amount of electrode slurry per unit area can be significantly reduced, and after sintering, the battery pulling force per unit area is effectively weakened. In this way, the abnormal warping of the battery is improved without losing battery performance.

[0040] Figure 3 This is a top view schematic diagram of a back-contact solar cell of an embodiment of the present invention, and takes an IBC cell as an example to illustrate the size design of the first grid line electrode and the second grid line electrode. However, it can be understood that the back-contact solar cell of the present invention is not limited to the IBC cell.

[0041] According to the embodiments of the present utility model, Figure 3As shown, the back-contact solar cell includes a first doping region 107 and a second doping region 108, which are arranged alternately to form an interdigitated structure; a first gate electrode 101 is formed on the first doping region 107, and a second gate electrode 102 is formed on the second doping region 108. The first gate electrode and the second gate electrode are distributed in equal proportions, which is conducive to simplifying the manufacturing process of the structure and also makes the collection of carriers more symmetrical.

[0042] According to the embodiment of the present invention, the first gate line electrodes 101 and the second gate line electrodes 102 may also be arranged alternately and staggered to form an interdigital structure, but the present invention is not limited thereto and may also be other structural types.

[0043] According to the embodiment of the present invention, the first gate line electrode 101 may be a P region gate line, and the second gate line electrode 102 may be an N region gate line. Based on the carrier transfer characteristics of the N region and the P region, the size of the N region gate line is usually smaller than that of the P region gate line.

[0044] Furthermore, taking the case where the first gate line electrode is made of aluminum and the second gate line electrode is made of silver as an example, there are differences in the composition and printing characteristics of the electrode pastes of the two. Since the metal powder particles of aluminum paste are relatively large and the line resistance is higher than that of silver metal, the printed height and width of the first gate line electrode are larger than those of the second gate line electrode.

[0045] Figure 4 FIG. 1 is a side view schematic diagram of a back-contact solar cell according to an embodiment of the present utility model. Figure 3 and Figure 4 As shown, the cross-sectional width of the first gate electrode 101 is the lateral distance on the cross section perpendicular to the direction where the length L1 is located, marked as W1; the cross-sectional width of the second gate electrode 102 is the lateral distance on the cross section perpendicular to the direction where the length L2 is located, marked as W2. The cross-sectional height of the first gate electrode 101 is the longitudinal distance on the above cross section, marked as H1; the cross-sectional height of the second gate electrode 102 is the longitudinal distance on the above cross section, marked as H2. It can be understood that the "lateral" here refers to the direction perpendicular to the thickness of the gate electrode, and the "longitudinal" refers to the direction along the thickness of the gate electrode.

[0046] According to the embodiment of the present utility model, the first gate line electrode 101 and the second gate line electrode 102 manufactured by screen printing are taken as an example. Figure 4 As shown, the cross-sections of the first gate line electrode 101 and the second gate line electrode 102 are triangular. To conveniently determine the cross-sectional area S1 of the first gate line electrode 101 and the cross-sectional area S2 of the second gate line electrode 102, the cross-sectional areas can be calculated according to formulas (2) and (3):

[0047] S1=n1*(H1*W1) / 2, (2);

[0048] S2=n2*(H2*W2) / 2, (3);

[0049] Wherein, n1 represents the correction coefficient of the actual cross-sectional area of ​​the first gate electrode, generally taking a value of 1 to 2, and n2 represents the correction coefficient of the actual cross-sectional area of ​​the second gate electrode, generally taking a value of 1 to 2. It should be noted that the correction coefficients may be different for different electrode pastes or printing process parameters.

[0050] According to an embodiment of the utility model, in order to more accurately determine the values ​​of the correction coefficients n1 and n2, the cross-sectional morphology of the first gate line electrode 101 and the second gate line electrode 102 can be respectively obtained by microscope scanning; based on the cross-sectional morphology, the actual cross-sectional areas S1 and S2, the cross-sectional widths W1 and W2, and the cross-sectional heights H1 and H2 of the first gate line electrode 101 and the second gate line electrode 102 are respectively determined; and then the correction coefficients n1 and n2 are respectively calculated based on formulas (2) and (3).

[0051] According to the embodiment of the utility model, the utility model optimizes the cross-sectional area of ​​the first gate electrode 101 and the second gate electrode 102 as shown in formula (1) to determine the relationship between the optimal printing states of the two. According to the relationship and the printing state of any gate electrode, the optimal printing state of the other gate electrode, that is, the optimal amount of slurry, can be calculated.

[0052] It can be further known that, from the perspective of printing specifications, reducing the amount of slurry per unit area can effectively reduce the warping abnormality caused by slurry shrinkage. However, it is also necessary to consider that the reduction in the amount of slurry is likely to lead to a reduction in performance. Therefore, the utility model also starts from the perspective of graphic optimization to reduce the amount of slurry per unit area without losing battery performance. Specifically, in order to reduce warping and at the same time minimize the loss of battery performance, the embodiment of the utility model optimizes the grid line spacing of the first grid line electrode 101 or the second grid line electrode 102.

[0053] According to an embodiment of the utility model, the grid line spacing of the first grid line electrode 101 or the second grid line electrode 102 is between 0.25 and 2 mm, for example, it can be 0.25 mm, 0.5 mm, 0.75 mm, 1.00 mm, 1.25 mm, 1.5 mm, 1.75 mm, 2 mm, etc. Preferably, the grid line spacing can be between 0.25 and 1.00 mm. By reducing the grid line spacing, that is, the grid line electrode becomes denser, the carrier collection effect can be enhanced, thereby reducing the cross-sectional area of ​​the grid line electrode at the same time, that is, it is considered to reduce the cross-sectional height and cross-sectional width at the same time, so that the slurry coverage per unit area can be significantly reduced without losing battery performance.

[0054] For example, assuming that Figure 4The gate line spacing W3 of the first gate line electrode 101 or the second gate line electrode 102 is reduced by 1 / 2, that is, the gate line spacing W3' of the first gate line electrode 101 or the second gate line electrode 102 after adjustment is W3 / 2. At this time, the carrier collection effect has been enhanced, so the height and width of the fine gate can also be reduced by 1 / 2 year-on-year. Figure 5 For the embodiment of the utility model relative to Figure 4 Schematic diagram of reducing the amount of electrode slurry after reducing the grid line spacing. That is, after adjustment, the cross-sectional width W1'=W1 / 2, and the cross-sectional height H1'=H1 / 2 of the first grid line electrode 101; after adjustment, the cross-sectional width W2'=W2 / 2, and the cross-sectional height H2'=H2 / 2 of the second grid line electrode 102. At this time, the amount of slurry per unit area is significantly reduced, and the pulling effect on the battery per unit area will be effectively weakened after sintering, so the warping of the entire battery can be effectively improved.

[0055] According to an embodiment of the utility model, after reducing the grid line spacing, it is recorded as W3'=n*W3, where n represents the multiple by which the grid line spacing can be narrowed compared to the current pattern. In order to improve the warping, the value of n can be between 0-1, preferably between 1 / 2-1. The smaller the value, the higher the requirements for process accuracy and printing state. Further, the cross-sectional dimensions of the first grid line electrode 101 and the second grid line electrode 102 are reduced. The cross-sectional width of the first grid line electrode can be calculated as W1'=n'×W1, and the cross-sectional height H1'=n'×H1; the cross-sectional width of the second grid line electrode can be calculated as W2'=n'×W2; the cross-sectional height H2'=n'×H2. Considering the mass production printing level and reducing the amount of slurry used, 2>n' / n>1, which provides a basis for the selection of the cross-sectional dimensions of the first grid line electrode 101 and the second grid line electrode 102.

[0056] According to the embodiment of the present invention, the cross-sectional area of ​​the first gate electrode 101 is 90-1300 μm 2 , for example, it can be 90 μm 2 , 200μm 2 , 400μm 2 、600μm 2 、800μm 2 , 1000μm 2 , 1200μm 2 、1300μm 2 The cross-sectional area of ​​the second gate electrode 102 is 90-1300 μm 2 , for example, it can be 90 μm 2 , 200μm 2 , 400μm 2 、600μm 2 、800μm 2 , 1000μm 2, 1200μm 2 、1300μm 2 The cross-sectional areas of the first gate electrode 101 and the second gate electrode 102 can more accurately reflect the amount of slurry used, and the cross-sectional areas of the two can be optimized. Within the above range, the mass production printing level can be met, and the amount of electrode slurry used is relatively small.

[0057] According to an embodiment of the utility model, further, the cross-sectional height H1 of the first gate line electrode 101 may be 10-30 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc., and the cross-sectional width W1 of the first gate line electrode 102 may be 90-150 μm, for example, 90 μm, 100 μm, 120 μm, 140 μm, 150 μm, etc. The cross-sectional height H2 of the second gate line electrode 102 may be 5-15 μm, for example, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, etc., and the cross-sectional width W2 of the second gate line electrode 102 may be 25-50 μm, for example, 25 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.

[0058] According to the embodiment of the present invention, the cross-sectional dimensions of the first gate line electrode 101 and the second gate line electrode 102 can meet the mass production printing level, and the amount of electrode paste used is small, which is conducive to reducing abnormal warping.

[0059] According to the embodiment of the present invention, the cross-sectional dimensions of the first gate electrode 101 and the second gate electrode 102 can be applicable to a wide range of electrode materials. The resistivity of the first gate electrode 101 and the resistivity of the second gate electrode 102 can be 1*10 -8 Ω·m~5*10 -8 Ω·m, selecting a gate electrode material with good conductivity is beneficial to improving battery performance. For example, the first gate electrode 101 and the second gate electrode 102 can be selected from aluminum, silver or copper, etc. The resistivity of different materials is a fixed value under a certain state, which can be determined by reference.

[0060] According to an embodiment of the present invention, the sintering temperature of the electrode paste of the first gate line electrode 101 and the second gate line electrode 102 after printing may be 600-900°C, for example, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, etc.

[0061] According to the embodiment of the utility model, Figure 1 and 2As shown, the surface of the back-contact solar cell 100 is also printed with a first main grid electrode 103 and a second main grid electrode 104; wherein the first grid line electrode 101 is connected to the first main grid electrode 103, and the second grid line electrode 102 is connected to the second main grid electrode 104. The current is collected by the first grid line electrode 101 to the first main grid electrode 103, and the current is collected by the second grid line electrode 102 to the second main grid electrode 104.

[0062] However, it can be understood that the first main gate electrode 103 and the second main gate electrode 104 are not necessary, and an external electrode can also be used as the main gate. The types of external electrodes include but are not limited to straight-through type, bamboo-joint type, solder point type, etc., which can be perpendicular to the gate line electrode. Of course, there may be other non-perpendicular situations.

[0063] According to an embodiment of the present invention, further optionally, a first metal pad 105 is further provided on the first main gate electrode 103, and a second metal pad 106 is further provided on the second main gate electrode 104. The first metal pad 105 and the second metal pad 106 mainly play the role of electrical connection and current collection.

[0064] According to the embodiment of the utility model, Figures 1 to 4 As shown, the back-contact solar cell 100 may include a substrate 109 , and a first gridline electrode 101 and a second gridline electrode 102 are formed on a surface of the substrate 109 .

[0065] Furthermore, the type of the back contact solar cell 100 may be an IBC cell, a POLO-IBC cell, a TBC cell, a TBC-HTJ (heterojunction) combined cell, an HPBC cell, etc. The substrate 109 may have different structures according to different cell types. For example, taking an IBC cell as an example, the substrate 109 may include a silicon substrate, a doping layer, and a surface passivation layer, etc.; taking a TBC cell as an example, the substrate 109 may include a silicon substrate, a tunneling oxide layer, a doped polysilicon layer, and a surface passivation layer, etc. Since the structure of the substrate 109 may adopt a relatively well-known structure, it will not be listed one by one here.

[0066] According to an embodiment of the present invention, a photovoltaic module is further provided, comprising the above-mentioned back-contact solar cell 100; wherein two adjacent back-contact solar cells 100 are connected by a welding ribbon.

[0067] According to the embodiment of the utility model, since the abnormal warping of the back-contact solar cell 100 is improved, the risk of fragmentation and cracking can be reduced when the photovoltaic module is subsequently manufactured through processes such as battery welding and packaging, thereby reducing the abnormality rate of the photovoltaic module manufacturing process.

[0068] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A back-contact solar cell, characterized in that: A first gate line electrode and a second gate line electrode are printed on the surface of the battery, and the first gate line electrode and the second gate line electrode are alternately arranged; The first gate line electrode and the second gate line electrode are configured to satisfy the size relationship shown in formula (1): ρ1 / S1≤v2 / S2<2ρ1 / S1, (1); Wherein, ρ1 is the resistivity of the first gate line electrode, ρ2 is the resistivity of the second gate line electrode, S1 is the cross-sectional area of ​​the first gate line electrode, and S2 is the cross-sectional area of ​​the second gate line electrode; Furthermore, a gate line spacing between the first gate line electrode or the second gate line electrode is 0.25-2 mm.

2. The back-contact solar cell according to claim 1, characterized in that: The first gate line electrode is a P region gate line, and the second gate line electrode is an N region gate line; Wherein, the cross-sectional height of the first gate line electrode is 10-30 μm, and the cross-sectional width of the first gate line electrode is 90-150 μm; The cross-sectional height of the second gate line electrode is 5-15 μm, and the cross-sectional width of the second gate line electrode is 25-50 μm.

3. The back-contact solar cell according to claim 1 or 2, characterized in that: The gate line spacing of the first gate line electrode or the second gate line electrode is 0.25-1 mm.

4. The back-contact solar cell according to claim 1 or 2, characterized in that: The cross-sectional area of ​​the first gate line electrode is 90 to 1300 μm 2 The cross-sectional area of ​​the second gate line electrode is 90 to 1300 μm 2 .

5. The back-contact solar cell according to claim 1 or 2, characterized in that: The resistivity of the first gate line electrode and the resistivity of the second gate line electrode are 1*10 -8 Ω·m~5*10 -8 Ω·m.

6. The back-contact solar cell according to claim 5, characterized in that: The first gate line electrode and the second gate line electrode are respectively selected from aluminum, silver or copper.

7. The back-contact solar cell according to claim 1, characterized in that: The cross sections of the first gate line electrode and the second gate line electrode are quasi-triangular.

8. The back-contact solar cell according to claim 1, characterized in that: The back-contact solar cell comprises a first doped region and a second doped region, which are alternately arranged to form an interdigitated structure; The first gate line electrode is formed on the first doping region, and the second gate line electrode is formed on the second doping region.

9. The back-contact solar cell according to claim 8, characterized in that: The surface of the back-contact solar cell is also printed with a first main grid electrode and a second main grid electrode; Wherein, the first gate line electrode is connected to the first main gate electrode, and the second gate line electrode is connected to the second main gate electrode.

10. A photovoltaic module, characterized in that: The back-contact solar cell comprises the back-contact solar cell according to any one of claims 1 to 9; wherein two adjacent back-contact solar cells are connected by a welding ribbon.

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