Grid line structure for solar cell, manufacturing method of grid line structure and solar cell

Abstract

The invention relates to the technical field of solar cells, and discloses a grid line structure for a solar cell, a manufacturing method of the grid line structure and the solar cell. The grid line structure comprises a non-contact channel induction electrode and a plurality of contact auxiliary grids which are distributed at intervals, the contact type auxiliary grids and the non-contact type channel induction electrodes are alternately arranged and are parallel to each other, so that the contact type auxiliary grids and the non-contact type channel induction electrodes are not in contact with each other, and / or each contact type auxiliary grid is in cross electric contact with the corresponding non-contact type channel induction electrode; the contact type auxiliary grid penetrates through the passivation layer and then makes ohmic contact with the silicon substrate, and the non-contact type channel induction electrode makes contact with the surface, away from the silicon substrate, of the passivation layer so that potential difference can be formed between the non-contact type channel induction electrode and the surface of the silicon substrate. The surface sheet resistance, the grid line resistance and the surface field effect passivation effect are optimized by optimizing the grid line structure, the carrier transverse transmission loss is reduced, Auger recombination of high-concentration doping is avoided, the filling factor, the open-circuit voltage and the conversion efficiency of the cell are improved, the working procedure is simplified, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a grid line structure for a solar cell, a manufacturing method thereof, and a solar cell. Background Art

[0002] Passivation is one of the important means to improve the power generation efficiency of solar cells. With the continuous optimization and improvement of passivation technology, in order to effectively avoid Auger recombination, the doping concentration is gradually optimized to a lower direction, which increases the resistance of the lateral transmission of photogenerated carriers on the surface of the silicon substrate, and ultimately leads to an increase in series resistance and a decrease in fill factor. For example, the TOPCon cell uses a tunnel passivation structure on the back (the tunnel passivation structure includes a tunnel oxide layer and a doped polysilicon layer sequentially deposited on the back of the silicon substrate), which affects the electrical transmission performance of the back of the silicon substrate to a certain extent; even for TOPCon cells that use Poly (polycrystalline silicon) thinning technology, the electrical transmission performance of the silicon substrate will be further affected.

[0003] In addition, the power generation efficiency of solar cells is often improved by optimizing the grid line structure at the metallization end, and the main optimization direction is to reduce metal recombination and series resistance.

[0004] Among them, the main way to reduce metal recombination is to optimize the contact area between metal (such as grid lines) and silicon substrate. For example, as shown in a grid line structure with local contact on the front surface of a solar cell disclosed in publication number CN104465805A, each grid line electrode has multiple sections of local contact metal electrodes and multiple sections of non-contact metal electrodes (the purpose of the non-contact metal electrodes is to connect the local contact metal electrodes to collect carriers), and the local contact metal electrodes and the non-contact metal electrodes are electrically connected; in this way, the contact area between the grid line on the front surface and the silicon substrate adopts a segmented line or point local contact method to reduce the metallization area, thereby reducing the recombination current in the metallization area.

[0005] As shown in a solar cell disclosed in publication number CN118588775A, its metal grid line includes a contact area and a non-contact area connected to each other, and the emitter includes a low concentration area and a high concentration area; on the grid line structure, the contact area of ​​the metal grid line is point-shaped, and the contact area of ​​the metal grid line needs to contact the intersection of the first transmission area and the second transmission area of ​​the high concentration area of ​​the emitter, and the non-contact area of ​​the metal grid line covers the contact area to output the carriers collected by the contact area; in this way, the point-shaped metal contact structure is realized by contacting the contact area of ​​the metal grid line with the high concentration area of ​​the emitter, so that the metal contact area accounts for a small proportion and the metal contact recombination is small.

[0006] Among them, the optimization direction of the series resistance is mainly to reduce the contact resistance and the gate line resistance. For example, as shown in a solar cell electrode structure disclosed in Publication No. CN216528907U, each group of first fine grids includes a plurality of intermittently arranged short grids, and the second fine grids are printed on the upper surface of the plurality of intermittent short grids, and the centers of the plurality of short grids in each group of first fine grids are located on the same straight line with the centers of the corresponding second fine grids, so as to optimize the gate line aspect ratio, and then reduce the series resistance by reducing the gate line resistance; at the same time, the intermittent short grids also have the effect of reducing metal composite by optimizing the contact area between the gate line and the silicon substrate (such as silicon wafer).

[0007] However, the contact areas of these existing grid lines (or metal grid lines or electrode structures) are all short grids with local contact in segmented lines or points (rather than continuous contact-type sub-grids), and compared with continuous contact-type sub-grids, the segmented lines or points of short grids have very limited current collection capabilities on the entire silicon substrate surface. Therefore, as shown in CN118588775A, the segmented lines or points of short grids of these existing metal grid lines need to be highly dependent on the high concentration area of ​​the emitter, and a graphical and cross-linked carrier transmission channel is formed through the high concentration area of ​​the emitter to improve the defect of the limited current collection capability of the segmented lines or points of short grids. Therefore, for solar cells using these existing metal grid lines, the emitter not only needs to prepare a low concentration area, but also needs to prepare a high concentration area. The introduction of high temperature processes will not only reduce the body minority carrier lifetime of silicon, but also increase the production cost of the battery. In addition, the high concentration area of ​​the emitter will greatly increase the Auger recombination of the solar cell, thereby affecting the passivation effect of the battery surface. Summary of the invention

[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a grid line structure for a solar cell and a manufacturing method thereof and a solar cell.

[0009] Based on this, the present invention discloses a grid line structure for a solar cell, wherein the solar cell comprises a silicon substrate, a passivation layer and a grid line structure sequentially arranged on the surface of the silicon substrate; the grid line structure comprises a non-contact channel induction electrode and a plurality of contact sub-grids distributed at intervals;

[0010] The contact sub-grids and the non-contact channel inducing electrodes are arranged alternately and parallel to each other so that the contact sub-grids and the non-contact channel inducing electrodes do not contact each other, and / or each contact sub-grid crosses or stacks with the non-contact channel inducing electrodes to make electrical contact;

[0011] The contact sub-gate passes through the passivation layer and makes ohmic contact with the silicon substrate, while the non-contact channel inducing electrode contacts a surface of the passivation layer away from the silicon substrate, so that a potential difference is formed between the non-contact channel inducing electrode and the surface of the silicon substrate when the solar cell generates electricity.

[0012] Preferably, the non-contact channel inducing electrode is a non-contact gate line and / or a non-contact conductive film, and the number of the non-contact channel inducing electrodes is one or more. When the non-contact channel inducing electrode is a non-contact conductive film, each contact sub-gate crosses with the non-contact conductive film to make electrical contact, or the non-contact conductive film is stacked and covered on each contact sub-gate to make electrical contact.

[0013] The conductivity type of the silicon substrate under the non-contact channel inducing electrode is the same as the conductivity type of the silicon substrate under the adjacent contact sub-gate.

[0014] Further preferably, a grid line structure for a solar cell further comprises a plurality of main grids distributed at intervals, and the plurality of main grids are arranged along a first direction; the non-contact channel inducing electrode and the contact sub-grid are arranged along a second direction; the first direction and the second direction intersect each other, so that the non-contact channel inducing electrode and the contact sub-grid are both electrically in contact with the main grid;

[0015] The number of the non-contact channel inducing electrodes is multiple, and the multiple non-contact channel inducing electrodes are distributed at intervals; the contact sub-grids and the non-contact channel inducing electrodes are arranged alternately and parallel to each other, so that the contact sub-grids and the non-contact channel inducing electrodes do not contact each other.

[0016] Further preferably, there are multiple non-contact channel inducing electrodes, which are spaced apart and arranged along a first direction; and multiple contact sub-grids are arranged along a second direction, and the first direction and the second direction intersect with each other, so that each non-contact channel inducing electrode intersects with multiple contact sub-grids to make electrical contact.

[0017] More preferably, the solar cell is a main grid cell, the grid line structure further comprises a plurality of main grids distributed at intervals, and the plurality of main grids are arranged along a first direction so that the non-contact channel inducing electrode and the main grid are parallel to each other and do not contact each other;

[0018] Alternatively, the solar cell is a busbar-less cell so as to collect current through an external welding ribbon.

[0019] Further preferably, a grid line structure for a solar cell further comprises a plurality of main grids distributed at intervals, and the plurality of main grids are arranged along the first direction;

[0020] The non-contact channel inducing electrode comprises a first channel inducing electrode arranged along the second direction and a second channel inducing electrode arranged along the first direction;

[0021] The plurality of contact-type sub-grids are arranged along a second direction, and the first direction intersects with the second direction, so that the first channel inducing electrode and the contact-type sub-grid are both in electrical contact with the main grid, and each second channel inducing electrode is intersected with the plurality of contact-type sub-grids for electrical contact, and the second channel inducing electrode is also intersected with the first channel inducing electrode for electrical contact;

[0022] The contact-type auxiliary grid and the first channel inducing electrode are arranged alternately and parallel to each other, so that the contact-type auxiliary grid and the first channel inducing electrode do not contact each other.

[0023] Further preferably, the density of the non-contact grid lines is less than 1000 lines / cm;

[0024] The cross-sectional shape of the non-contact gate line is at least one of a rectangle, a triangle, a trapezoid, and an ellipse;

[0025] The material of the non-contact grid lines is silver and / or base metal.

[0026] Further preferably, the non-contact conductive film is a non-contact transparent conductive film or a non-contact non-transparent conductive film;

[0027] The thickness of the non-contact transparent conductive film is less than or equal to 20 μm;

[0028] The non-contact conductive film is a metal conductive film and / or a non-metal conductive film, and the material of the metal conductive film is silver and / or base metal.

[0029] The present invention also discloses a method for manufacturing a grid line structure for a solar cell, which comprises the following manufacturing steps:

[0030] Step 1, preparing a silicon substrate having a passivation layer on the surface;

[0031] Step 2, printing contact type sub-gate slurry and non-contact type channel induction electrode slurry on the surface of the passivation layer in sequence;

[0032] Step 3: sintering to obtain the gate line structure.

[0033] The present invention further discloses a solar cell, wherein the front side and / or the back side of the solar cell is provided with the grid line structure for the solar cell described in the present invention.

[0034] Compared with the prior art, the present invention has at least the following beneficial effects:

[0035] The existing metallization terminal technology optimizes the series resistance mainly to reduce the gate line resistance and contact resistance (as shown in publication number CN216528907U). In addition, the existing gate line structure uses segmented linear or dot-shaped short gates to collect current on the surface of the silicon substrate.

[0036] Based on this, 1. In the grid line structure of the present invention, on the basis of the continuous contact sub-grid, a continuous non-contact channel induction electrode is matched, so that when the solar cell is working, a conductive layer that is conducive to carrier transmission is formed on the surface of the silicon substrate, reducing the loss of lateral carrier transmission, thereby improving the fill factor of the solar cell. Moreover, in the grid line structure of the present invention, the continuous contact sub-grid is matched with each other, instead of the existing grid line structure: using segmented linear or point-shaped short grids; therefore, the solar cell of the present invention does not need to be highly doped on the surface of the silicon substrate to obtain an emitter with a high concentration area, so the preparation process of the solar cell of the present invention is simpler, and it can also effectively avoid the increase of Auger recombination and the reduction of passivation effect caused by high concentration doping.

[0037] 2. In the gate line structure of the present invention, the continuous contact sub-gate is in direct electrical contact with the silicon substrate to collect the photogenerated carriers generated in the silicon substrate to the main gate; and the non-contact channel inducing electrode is not in direct electrical contact with the silicon substrate. Therefore, through the cooperation between the continuous contact sub-gate and the continuous non-contact channel inducing electrode, when the solar cell generates electricity, the potential of the non-contact channel inducing electrode is not equal to the potential of the silicon substrate surface, forming a potential difference, which will induce the formation of multi-carrier accumulation on the silicon substrate surface below the non-contact channel inducing electrode, forming a low-resistance channel that is conducive to the lateral transmission of multi-carriers on the silicon substrate surface, and reducing the series resistance of the solar cell by reducing the surface square resistance of the silicon substrate below the non-contact channel inducing electrode.

[0038] 3. At the same time, the potential difference will induce energy band bending on the surface of the silicon substrate, increase the majority carrier density and reduce the minority carrier density on the surface of the silicon substrate, reduce the carrier recombination in this area, and thus achieve the effect of surface passivation. Since the surface passivation is caused by the potential difference (electric field), the gate line structure of the present invention also achieves a field effect passivation effect on the surface of the silicon substrate.

[0039] 4. In summary, the present invention optimizes the surface square resistance, grid line resistance and surface field effect passivation effect of solar cells by optimizing the grid line structure and cooperating between a continuous contact sub-grid and a continuous non-contact channel inducing electrode, thereby reducing the loss of lateral carrier transport and avoiding the increase of Auger recombination and the reduction of passivation effect caused by high-concentration doping, so as to further improve the fill factor, open circuit voltage and conversion efficiency of solar cells, simplify the process and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a top view of the gate line structure in which the non-contact gate line and the contact sub-gate are parallel to each other in Embodiment 1-2.

[0041] Figure 2It is a cross-sectional view of the gate line structure in which the non-contact gate line and the contact sub-gate are parallel in embodiment 1-2.

[0042] Figure 3 This is a cross-sectional view of a gate line structure in which a non-contact gate line covers a single contact sub-gate intersection according to comparative example 2.

[0043] Figure 4 It is a top view of the gate line structure in which the non-contact gate line and the contact sub-gate cross each other according to the third embodiment.

[0044] Figure 5 It is a cross-sectional view of a gate line structure in which a non-contact gate line and a contact sub-gate cross each other according to Embodiment 3.

[0045] Figure 6 It is a cross-sectional view of the gate line structure where the non-contact conductive film and the contact sub-gate intersect in Example 5.

[0046] Figure 7 It is a top view of the gate line structure in which the non-contact gate line and the contact sub-gate are both crossed and parallel to each other according to the fourth embodiment.

[0047] Figure 8 It is a cross-sectional view of a gate line structure in which a non-contact gate line and a contact sub-gate are both crossed and parallel to each other according to Embodiment 4.

[0048] Description of the accompanying drawings: main gate 1; non-contact channel inducing electrode 2; first non-contact gate line 21; second non-contact gate line 22; contact sub-gate 3; passivation layer 4; silicon substrate 5. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] A solar cell of this embodiment, see Figure 1-2 , which includes a silicon substrate 5 and a passivation layer 4 and a grid line structure sequentially arranged on the surface of the silicon substrate 5. In practice, the solar cell can be a busbar-free cell or a busbar-equipped cell; when the solar cell is a busbar-free cell, a welding strip can be used instead of the busbar 1 to collect current.

[0052] In this embodiment, the solar cell is a main grid cell, and the grid line structure is a grid line structure as shown below in this embodiment.

[0053] Specifically, the solar cell of the present embodiment is preferably a TOPCon cell, and other structures of the TOPCon cell are referred to the existing TOPCon cells, so they are not described in detail.

[0054] In practice, the grid line structure shown in the embodiment can be applied to both the front and back sides of the solar cell. However, for experimental cost considerations, in the embodiment, only the back side of the TOPCon solar cell is applied with the grid line structure shown in the embodiment, while the front side of the TOPCon solar cell is not applied with the grid line structure shown in the embodiment (the front side of the TOPCon solar cell adopts the traditional grid line structure consisting of a main grid and a secondary grid).

[0055] A gate line structure of this embodiment, see Figure 1-2 , including a main gate 1, a contact type sub-gate 3 and a non-contact type channel inducing electrode 2. The number of the main gates 1 is preferably multiple. The multiple main gates 1 are arranged along the first direction, and the multiple main gates 1 are spaced apart from each other.

[0056] The number of the contact sub-gates 3 is preferably multiple. The multiple contact sub-gates 3 are arranged along the second direction, and the multiple contact sub-gates 3 are spaced apart from each other. Each contact sub-gate 3 directly makes ohmic contact with the silicon substrate 5 after passing through the passivation layer 4, so that the contact sub-gate 3 is used to collect current on the surface of the silicon substrate 5.

[0057] In practice, the first direction and the second direction intersect each other. Preferably, the first direction and the second direction are perpendicular to each other, for example, the first direction is the y-axis direction, and the second direction is the x-axis direction. In practice, the contact type auxiliary grid 3 can be made of a burn-through metal grid line paste.

[0058] Compared with the existing segmented linear or dot-shaped short gates, the contact-type auxiliary gate 3 of this embodiment is continuous, which can greatly improve the current collection capability of the entire silicon substrate 5 surface.

[0059] Moreover, each contact-type auxiliary grid 3 is in electrical contact with a plurality of main grids 1, so that the main grid 1 collects the current on the contact-type auxiliary grid 3 and transmits the collected current to the output end of the solar cell for use by external electrical equipment.

[0060] In this embodiment, the non-contact channel inducing electrode 2 is a non-contact gate line; the number of the non-contact gate lines can be one or more, preferably multiple. The multiple non-contact gate lines are also arranged along the second direction (such as the x-axis direction), and the multiple non-contact gate lines are spaced apart from each other; each non-contact gate line is in electrical contact with the multiple main gates 1.

[0061] In practice, for cost considerations, the density of non-contact gate lines is less than 1000 / cm. The density of non-contact gate lines directly affects the width of the non-contact gate lines and the spacing between the non-contact gate lines; if the density of non-contact gate lines is too large, the width of the non-contact gate lines will be very small, which is difficult to achieve in terms of technology. Even if it can be achieved in terms of technology, the cost will be too high.

[0062] Moreover, the contact type auxiliary grid 3 and the non-contact type grid lines are arranged in parallel with each other, and the contact type auxiliary grid 3 and the non-contact type grid lines are arranged alternately with each other, and the contact type auxiliary grid 3 and the non-contact type grid lines do not contact each other.

[0063] Furthermore, the non-contact gate line is located on the surface of the passivation layer 4 , and the non-contact gate line does not directly make ohmic contact with the silicon substrate 5 , so that the non-contact gate line is used to construct a better carrier transmission channel.

[0064] In practice, the non-contact gate line can be made of non-burn-through metal gate line paste. The material of the non-contact gate line is at least one of silver and base metal (such as copper, aluminum, etc.) (such as silver); the cross-section of the non-contact gate line is at least one of a rectangle (such as a square, a rectangle), a triangle, a trapezoid, and an ellipse. In a gate line structure of this embodiment, the conductivity type of the silicon substrate 5 under the non-contact channel induction electrode 2 is the same as the conductivity type of the silicon substrate 5 under the adjacent contact sub-gate 3 (such as N-type or P-type).

[0065] A method for manufacturing a gate line structure in this embodiment includes the following manufacturing steps:

[0066] Step 1: Prepare a silicon substrate 5 having a passivation layer 4 on its surface.

[0067] Step 2: Printing the main gate paste, the contact type sub-gate paste and the non-contact type channel induction electrode paste on the surface of the passivation layer 4 in sequence.

[0068] Step 3: sintering to obtain a gate line structure including the contact type auxiliary gate 3 , the non-contact type gate line and the main gate 1 .

[0069] Example 2

[0070] A gate line structure and a manufacturing method thereof of this embodiment are both referred to in Embodiment 1. The difference between this embodiment and Embodiment 1 is that:

[0071] The silicon substrate 5 with the passivation layer 4 and the TOPCon cell of this embodiment are from different batches than those of Example 1. Therefore, the performance test results of the TOPCon cell of this embodiment are slightly different from those of Example 1.

[0072] Example 3

[0073] A grid line structure and a manufacturing method thereof and a solar cell in this embodiment are all referred to in Embodiment 1. The difference between this embodiment and Embodiment 1 is that:

[0074] See also Figure 4-5 The non-contact channel inducing electrode 2 (such as non-contact gate line) in a gate line structure of this embodiment is different from that of Embodiment 1 in the following aspects:

[0075] In the gate line structure of the present embodiment, a plurality of non-contact gate lines are arranged along a first direction (such as the y-axis direction), and the plurality of non-contact gate lines are spaced apart from each other; each non-contact gate line is electrically contacted with a plurality of contact sub-gates 3 by crossing each other (preferably perpendicular to each other), and a side of the contact sub-gate 3 away from the silicon substrate 5 is lower than a side of the non-contact gate line away from the passivation layer 4.

[0076] Moreover, the non-contact gate line and the main gate 1 are arranged parallel to each other, and the non-contact gate line and the main gate 1 do not contact each other.

[0077] Example 4

[0078] A grid line structure and a manufacturing method thereof and a solar cell in this embodiment are all referred to in Embodiment 1. The difference between this embodiment and Embodiment 1 is that:

[0079] See also Figure 7-8 The non-contact channel inducing electrode 2 in a gate line structure of this embodiment is different from that in embodiment 1 as follows:

[0080] In the gate line structure of this embodiment, the non-contact channel inducing electrode 2 includes a first non-contact gate line 21 (corresponding to the first channel inducing electrode) and a second non-contact gate line 22 (corresponding to the second channel inducing electrode).

[0081] The plurality of first non-contact gate lines 21 are arranged along the second direction (eg, the x-axis direction), so the first non-contact gate lines 21 are arranged parallel to the contact sub-gate 3. The specific arrangement of the first non-contact gate lines 21 can refer to the non-contact gate lines in the first embodiment.

[0082] Among them, the plurality of second non-contact gate lines 22 are arranged along the first direction (such as the y-axis direction), so each second non-contact gate line 22 is electrically contacted with the plurality of contact sub-gates 3 by crossing each other (preferably perpendicular to each other). The specific arrangement of the second non-contact gate line 22 can refer to the non-contact gate line in embodiment 3.

[0083] Furthermore, the first non-contact gate line 21 and the second non-contact gate line 22 are also electrically contacted by crossing each other (preferably being perpendicular to each other).

[0084] Example 5

[0085] A grid line structure and a manufacturing method thereof and a solar cell in this embodiment are all referred to in Embodiment 3. The difference between this embodiment and Embodiment 3 is that:

[0086] See also Figure 6The non-contact channel inducing electrode 2 in a gate line structure of this embodiment is different from that of the embodiment 3 in the following aspects:

[0087] In the gate line structure of this embodiment, the non-contact channel induction electrode 2 is a non-contact conductive film, which is a non-contact transparent conductive film or a non-contact non-transparent conductive film.

[0088] In practice, mainly for the sake of production cost and battery conversion efficiency, the thickness of the non-contact conductive film (preferably a non-contact transparent conductive film) is less than or equal to 20 μm. This is because: if the non-contact transparent conductive film is applied to the front of the solar cell, the non-contact transparent conductive film is too thick, which will increase the parasitic absorption of light, thereby reducing the battery conversion efficiency. If the non-contact transparent conductive film is applied to the back of the solar cell, the non-contact transparent conductive film is too thick, which will not only increase the manufacturing cost, but also may cause the solar cell to warp, increase the defective rate of the solar cell, and ultimately increase the production cost of the solar cell.

[0089] The non-contact conductive film is at least one of a metal conductive film and a non-metal conductive film. The material of the metal conductive film is at least one of silver and base metal (such as copper, aluminum, etc.).

[0090] Comparative Example 1

[0091] A grid line structure and a manufacturing method thereof and a solar cell in this comparative example are all referred to in Example 1, and the difference between them and Example 1 is that:

[0092] A gate line structure of this comparative example does not have a non-contact channel inducing electrode 2. Correspondingly, in the method for manufacturing a gate line structure of this comparative example, the printing process of the non-contact channel inducing electrode paste is omitted in step 2. Therefore, a solar cell of this comparative example is a TOPCon cell without applying the non-contact channel inducing electrode 2.

[0093] Comparative Example 2

[0094] A grid line structure and a manufacturing method thereof and a solar cell in this comparative example are all referred to in Example 2, and the difference between this comparative example and Example 2 is that:

[0095] A grid line structure of the comparative example, see Figure 3 , its non-contact channel inducing electrode 2 (such as non-contact gate line) covers a single contact sub-gate 3 (rather than a gate line structure like embodiment 2: its non-contact gate line and contact sub-gate 3 are arranged alternately, and the contact sub-gate 3 and the non-contact gate line are parallel to each other and do not contact each other).

[0096] Comparative Example 3

[0097] A grid line structure and a manufacturing method thereof and a solar cell in this comparative example are all referred to in Example 3, and the difference between this comparative example and Example 3 is that:

[0098] A gate line structure of this comparative example does not have a non-contact channel inducing electrode 2. Correspondingly, in the method for manufacturing a gate line structure of this comparative example, the printing process of the non-contact channel inducing electrode paste is omitted in step 2. Therefore, a solar cell of this comparative example is a TOPCon cell without applying the non-contact channel inducing electrode 2.

[0099] Comparative Example 4

[0100] A grid line structure and a manufacturing method thereof and a solar cell in this comparative example are all referred to in Example 4, and the difference between this comparative example and Example 4 is that:

[0101] A gate line structure of this comparative example does not have a non-contact channel inducing electrode 2. Correspondingly, in the method for manufacturing a gate line structure of this comparative example, the printing process of the non-contact channel inducing electrode paste is omitted in step 2. Therefore, a solar cell of this comparative example is a TOPCon cell without applying the non-contact channel inducing electrode 2.

[0102] Performance Testing

[0103] 1. The TOPCon batteries of Example 1 and Comparative Example 1 were respectively subjected to performance tests. The number of TOPCon batteries used for performance tests of Example 1 and Comparative Example 1 was 50. After excluding abnormal performance test data and taking the average value, the test results shown in Table 1 were obtained.

[0104] Table 1

[0105] Experimental Group Eta / % Voc / mV Isc / A FF / % Comparative Example 1 26.40 740.2 14.102 84.67 Example 1 26.63 740.3 14.100 85.39

[0106] 2. The TOPCon batteries of Example 2 and Comparative Example 2 were respectively subjected to performance tests. The number of TOPCon batteries used for performance tests of Example 2 and Comparative Example 2 was 50. After excluding abnormal performance test data and taking the average value, the test results shown in Table 2 below were obtained.

[0107] Table 2

[0108]

[0109]

[0110] 3. The TOPCon batteries of Example 3 and Comparative Example 3 were respectively subjected to performance tests. The number of TOPCon batteries used for performance tests of Example 3 and Comparative Example 3 was 50. After excluding abnormal performance test data and taking the average value, the test results shown in Table 3 were obtained.

[0111] Table 3

[0112] Experimental Group Eta / % Voc / mV Isc / A FF / % Comparative Example 3 26.28 740.4 14.084 84.35 Example 3 26.52 741.1 14.103 84.93

[0113] 4. The TOPCon batteries of Example 4 and Comparative Example 4 were respectively subjected to performance tests. The number of TOPCon batteries used for the performance tests of Example 4 and Comparative Example 4 was 50. After excluding abnormal performance test data and taking the average value, the test results shown in Table 4 were obtained.

[0114] Table 4

[0115] Experimental Group Eta / % Voc / mV Isc / A FF / % Comparative Example 4 26.23 741.5 14.121 83.86 Example 4 26.56 742.6 14.111 84.83

[0116] In Table 1-4, Eta is the conversion efficiency of the battery, Voc is the open circuit voltage, Isc is the short circuit current, and FF is the fill factor.

[0117] In summary, the present invention optimizes the surface square resistance, grid line resistance and surface passivation effect (i.e., field effect passivation effect on the surface of silicon substrate) of solar cells by optimizing the grid line structure and cooperating with the continuous contact sub-grid and the continuous non-contact channel induction electrode, and reduces the loss of lateral carrier transmission, so as to further improve the fill factor, open circuit voltage and conversion efficiency of solar cells (see Table 1-4). The non-contact channel induction electrode can use some low-cost materials (such as base metal materials) to achieve the effect of the present invention, so it can also reduce the production cost and raw material cost of solar cells.

[0118] Among them, the gate line structure of the present invention uses the mutual cooperation of a continuous contact sub-gate and a continuous non-contact channel inducing electrode, rather than the existing gate line structure: using a segmented linear or dot-shaped short gate; therefore, the solar cell of the present invention does not need to be highly doped on the surface of the silicon substrate to obtain an emitter with a high concentration area, so the preparation process of the solar cell of the present invention is simpler, and can effectively avoid the increase of Auger recombination and the reduction of passivation effect caused by high concentration doping.

[0119] In addition, especially when the non-contact conductive film is stacked and covered on each contact sub-gate for electrical contact, the non-contact conductive film is superior to the non-contact gate line in terms of the area where the effect of the present invention is exerted. Therefore, the gate line structure of Example 5 is superior to the gate line structures of Examples 1-3 in terms of realizing the carrier transmission channel and the surface field effect passivation of the silicon substrate. Figure 6 The non-contact conductive film shown can also assist in transmitting the carriers collected by the contact-type auxiliary grid to the external circuit, thereby reducing the series resistance of the battery. Therefore, the non-contact conductive film is superior to the non-contact grid line in terms of comprehensive performance.

[0120] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0121] The technical solution provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A grid line structure for a solar cell, the solar cell comprising a silicon substrate and a passivation layer and a grid line structure sequentially arranged on the surface of the silicon substrate; characterized in that: The gate line structure includes a non-contact channel induction electrode and a plurality of contact sub-gates distributed at intervals; The contact sub-grids and the non-contact channel inducing electrodes are arranged alternately and parallel to each other so that the contact sub-grids and the non-contact channel inducing electrodes do not contact each other, and / or each contact sub-grid crosses or stacks with the non-contact channel inducing electrodes to make electrical contact; The contact sub-gate passes through the passivation layer and makes ohmic contact with the silicon substrate, while the non-contact channel inducing electrode contacts a surface of the passivation layer away from the silicon substrate, so that a potential difference is formed between the non-contact channel inducing electrode and the surface of the silicon substrate when the solar cell generates electricity.

2. A grid line structure for a solar cell according to claim 1, characterized in that: The non-contact channel inducing electrode is a non-contact gate line and / or a non-contact conductive film, and the number of the non-contact channel inducing electrodes is one or more; The conductivity type of the silicon substrate under the non-contact channel inducing electrode is the same as the conductivity type of the silicon substrate under the adjacent contact sub-gate.

3. A grid line structure for a solar cell according to claim 1 or 2, characterized in that: It also includes a plurality of main grids distributed at intervals, and the plurality of main grids are arranged along a first direction; the non-contact channel inducing electrode and the contact sub-grid are arranged along a second direction; the first direction and the second direction intersect each other, so that the non-contact channel inducing electrode and the contact sub-grid are both electrically in contact with the main grid; The number of the non-contact channel inducing electrodes is multiple, and the multiple non-contact channel inducing electrodes are distributed at intervals; the contact sub-grids and the non-contact channel inducing electrodes are arranged alternately and parallel to each other, so that the contact sub-grids and the non-contact channel inducing electrodes do not contact each other.

4. A grid line structure for a solar cell according to claim 1 or 2, characterized in that: There are multiple non-contact channel inducing electrodes, which are spaced apart and arranged along a first direction; and multiple contact sub-grids are arranged along a second direction, and the first direction and the second direction intersect with each other, so that each non-contact channel inducing electrode intersects with multiple contact sub-grids to make electrical contact.

5. A grid line structure for a solar cell according to claim 4, characterized in that: The solar cell is a main grid cell, and the grid line structure further includes a plurality of main grids distributed at intervals, and the plurality of main grids are arranged along a first direction so that the non-contact channel inducing electrode and the main grid are parallel to each other and do not contact each other; Alternatively, the solar cell is a busbar-less cell so as to collect current through an external welding ribbon.

6. A grid line structure for a solar cell according to claim 1 or 2, characterized in that: It also includes a plurality of main grids that are spaced apart, and the plurality of main grids are arranged along a first direction; The non-contact channel inducing electrode comprises a first channel inducing electrode arranged along the second direction and a second channel inducing electrode arranged along the first direction; The plurality of contact-type sub-grids are arranged along a second direction, and the first direction intersects with the second direction, so that the first channel inducing electrode and the contact-type sub-grid are both in electrical contact with the main grid, and each second channel inducing electrode is intersected with the plurality of contact-type sub-grids for electrical contact, and the second channel inducing electrode is also intersected with the first channel inducing electrode for electrical contact; The contact-type auxiliary grid and the first channel inducing electrode are arranged alternately and parallel to each other, so that the contact-type auxiliary grid and the first channel inducing electrode do not contact each other.

7. The grid line structure for solar cells according to claim 2, characterized in that: The density of the non-contact grid lines is less than 1000 / cm; The cross-sectional shape of the non-contact gate line is at least one of a rectangle, a triangle, a trapezoid, and an ellipse; The material of the non-contact grid lines is silver and / or base metal.

8. The grid line structure for solar cells according to claim 2, characterized in that: The non-contact conductive film is a non-contact transparent conductive film or a non-contact non-transparent conductive film; The thickness of the non-contact transparent conductive film is less than or equal to 20 μm; The non-contact conductive film is a metal conductive film and / or a non-metal conductive film, and the material of the metal conductive film is silver and / or base metal.

9. The method for manufacturing a grid line structure for a solar cell according to claim 1, characterized in that: It includes the following production steps: Step 1, preparing a silicon substrate having a passivation layer on the surface; Step 2, printing contact type sub-gate slurry and non-contact type channel induction electrode slurry on the surface of the passivation layer in sequence; Step 3: sintering to obtain the gate line structure.

10. A solar cell, characterized in that: The front and / or back of the solar cell is provided with a grid line structure for a solar cell as claimed in any one of claims 1 to 8.

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