Grid line structure for solar cell, solar cell and photovoltaic module

Abstract

The utility model relates to the technical field of solar cells, and discloses a grid line structure for a solar cell, the solar cell and a photovoltaic module. The grid line structure comprises a strip-shaped 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 crossed or stacked electric contact with the non-contact type channel induction electrodes; 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 fill factor, the open-circuit voltage and the conversion efficiency of the cell are improved, and the cost can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of solar cell, specifically relates to a grid line structure for solar cell, solar cell and photovoltaic module. BACKGROUND

[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, to effectively avoid Rutherford recombination, the doping concentration is gradually optimized in the direction of lower, resulting in the increase of the resistance of the lateral transmission of photo-generated carriers on the surface of the silicon substrate, and ultimately leading to the increase of the series resistance and the decrease of the fill factor. For example, the back surface of the TOPCon cell adopts a tunneling passivation structure (the tunneling passivation structure includes a tunneling oxide layer and a doped polysilicon layer deposited on the back surface of the silicon substrate in sequence), which affects the electrical transmission performance of the back surface of the silicon substrate. Even for the TOPCon cell using Poly (polysilicon) thinning technology, the electrical transmission performance of the silicon substrate will be further affected.

[0003] In addition, the grid line structure is often optimized to improve the power generation efficiency of solar cells 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 the metal (such as grid line) and the silicon substrate. For example, as shown in the grid line structure of the positive surface of the solar cell disclosed in publication No. CN104465805A, each grid line electrode has multiple local contact metal electrodes and multiple non-contact metal electrodes (the purpose of the non-contact metal electrode is to connect the local contact metal electrode to collect carriers), and the local contact metal electrode and the non-contact metal electrode are electrically connected; in this way, the contact area between the grid line on the positive surface and the silicon substrate adopts a segmented line or point local contact mode to reduce the metallization area, thereby reducing the recombination current of the metallization area.

[0005] For example, as shown in the solar cell disclosed in publication No. CN118588775A, the 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 be in contact with 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 is covered on the contact area to output the carriers collected by the contact area; in this way, by contacting the contact area of the metal grid line with the high concentration area of the emitter, a point-shaped metal contact structure is realized to make the proportion of the metal contact area small and the metal contact recombination small.

[0006] The optimization direction of the series resistance is mainly to reduce the contact resistance and the gate line resistance. For example, a solar cell electrode structure disclosed in a publication No. CN216528907U shows that each group of first fine gates includes a plurality of intermittently arranged short gates, a second fine gate is printed on the upper surface of the plurality of intermittently arranged short gates, and the centers of the plurality of short gates in each group of first fine gates and the centers of the corresponding second fine gates are located on the same straight line, 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 intermittently arranged short gates also have the effect of reducing the metal recombination by optimizing the contact area between the gate line and the silicon substrate (such as a silicon wafer).

[0007] However, the contact areas of the existing gate line structures (or metal gate lines or electrode structures) are all segmented linear or point-like local contact short gates (rather than strip-like contact sub-gates), and compared with the strip-like contact sub-gates, the segmented linear or point-like short gates have very limited current collection capacity on the entire silicon substrate surface. Therefore, as shown in CN118588775A, the existing segmented linear or point-like short gates of the metal gate lines need to highly depend on the high concentration area of the emitter to form a patterned and cross-linked carrier transport channel through the high concentration area of the emitter, so as to improve the defect of limited current collection capacity of the segmented linear or point-like short gates. Therefore, the solar cell using the existing metal gate lines needs to not only prepare a low concentration area but also prepare a high concentration area, and the introduction of high-temperature process not only reduces the bulk minority carrier lifetime of silicon but also increases the production cost of the cell. In addition, the high concentration area of the emitter also greatly increases the Auger recombination of the solar cell, thereby affecting the passivation effect of the cell surface. Practical new type content

[0008] The utility model aims at overcoming the prior art's insufficient, provides a kind of grid line structure for solar cell, solar cell and photovoltaic module.

[0009] Based on this, the utility model discloses a kind of grid line structure for solar cell, the solar cell includes silicon substrate and passivation layer and grid line structure sequentially in silicon substrate surface;The grid line structure includes non-contact channel inducing electrode and several interval distribution contact sub-gate;

[0010] The contact sub-gate and non-contact channel inducing electrode are alternately arranged and parallel to each other to make contact sub-gate and non-contact channel inducing electrode not contact each other, and / or, each contact sub-gate is crossed or stacked with non-contact channel inducing electrode to be electrically contacted;

[0011] Both the contact sub-gate and the non-contact channel induction electrode are strip-shaped. The contact sub-gate makes ohmic contact with the silicon substrate after passing through the passivation layer, while the non-contact channel induction 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 induction electrode and the surface of the silicon substrate when the solar cell generates electricity.

[0012] Preferably, the non-contact channel induction electrode is a non-contact gate line and / or a non-contact conductive film, and the number of non-contact channel induction electrodes is one or more. When the non-contact channel induction electrode is a non-contact conductive film, each contact sub-gate makes electrical contact with the non-contact conductive film by crossing each other, or the non-contact conductive film is stacked and covers each contact sub-gate to make electrical contact.

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

[0014] More preferably, a grid structure for a solar cell further includes a plurality of spaced main grids, all of which are arranged along a first direction; a non-contact channel induction electrode and a contact sub-grid are both arranged along a second direction; the first direction and the second direction intersect each other, so that both the non-contact channel induction electrode and the contact sub-grid are in electrical contact with the main grids;

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

[0016] More preferably, the number of non-contact channel induction electrodes is multiple, and the multiple non-contact channel induction electrodes are distributed at intervals and are all arranged along the first direction; while the several contact sub-gates are arranged along the second direction, and the first direction and the second direction intersect each other, so that each non-contact channel induction electrode makes electrical contact with several contact sub-gates.

[0017] More preferably, the solar cell is a grid cell, and the grid structure further includes a plurality of spaced grids, and the plurality of grids are arranged along a first direction so that the non-contact channel induced electrode and the grids are parallel to each other and do not contact each other.

[0018] Alternatively, the solar cell may be a gridless cell, in which current is collected via external solder strips.

[0019] More preferably, a grid structure for a solar cell further includes a plurality of spaced main grids, and the plurality of main grids are arranged along a first direction;

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

[0021] The plurality of contact sub-gates are arranged along the second direction, and the first direction and the second direction intersect each other, so that the first channel induction electrode and the contact sub-gates are electrically in contact with the main gate, and each second channel induction electrode intersects with the plurality of contact sub-gates to make electrical contact, and the second channel induction electrode also intersects with the first channel induction electrode to make electrical contact.

[0022] The contact sub-gate and the first channel induction electrode are arranged alternately and parallel to each other, so that the contact sub-gate and the first channel induction electrode do not come into contact with each other.

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

[0024] The cross-sectional shape of the non-contact grid line is at least one of the following: rectangular, triangular, trapezoidal, and elliptical.

[0025] Non-contact grid lines are silver grid lines and / or base metal grid lines.

[0026] More 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, wherein the metal conductive film is a silver conductive film and / or a base metal conductive film.

[0029] This utility model also discloses a solar cell, wherein the front and / or back of the solar cell are provided with the grid structure for a solar cell described above.

[0030] This utility model also discloses a photovoltaic module, comprising a photovoltaic front panel, a battery layer, and a photovoltaic back panel stacked sequentially; the battery layer is a solar cell as described above in this utility model.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] Existing metallization techniques primarily optimize series resistance by reducing gate line resistance and contact resistance (as shown in publication CN216528907U). Furthermore, existing gate line structures employ segmented linear or dotted short gates to collect current from the silicon substrate surface.

[0033] Based on this, 1. In the grid structure of this utility model, a strip-shaped non-contact channel induction electrode is combined with a strip-shaped contact sub-grid, so that a conductive layer conducive to carrier transport is formed on the silicon substrate surface during solar cell operation, reducing the loss of carrier lateral transport and thus improving the fill factor of the solar cell. Moreover, in the grid structure of this utility model, a strip-shaped contact sub-grid is used in conjunction with the grid structure, instead of the segmented line or dot short grid structure of the existing grid structure; therefore, the solar cell of this utility model does not need to perform high-concentration doping on the silicon substrate surface to obtain an emitter with a high-concentration region. Therefore, the fabrication process of the solar cell of this utility model is simpler and the fabrication cost is lower, and it can also effectively avoid the increase of Auger recombination and the reduction of passivation effect caused by high-concentration doping.

[0034] 2. In the grid structure of this invention, the strip-shaped contact sub-grid is in direct electrical contact with the silicon substrate, collecting photogenerated carriers generated in the silicon substrate and transferring them to the main grid; while the non-contact channel induction electrode is not in direct electrical contact with the silicon substrate. Therefore, through the cooperation of the strip-shaped contact sub-grid and the strip-shaped non-contact channel induction electrode, when the solar cell generates electricity, the potential of the non-contact channel induction electrode is unequal to the potential of the silicon substrate surface, forming a potential difference. This potential difference induces majority carrier accumulation on the silicon substrate surface below the non-contact channel induction electrode, forming a low-resistance channel that facilitates the lateral transport of majority carriers on the silicon substrate surface. By reducing the surface sheet resistance of the silicon substrate below the non-contact channel induction electrode, the series resistance of the solar cell is reduced.

[0035] 3. At the same time, the potential difference induces band bending on the surface of the silicon substrate, which increases the majority carrier density and decreases the minority carrier density on the surface of the silicon substrate, thereby reducing carrier recombination in the region and achieving the effect of surface passivation. Since the surface passivation is caused by the potential difference (electric field), the gate structure of this invention also achieves the field effect passivation effect on the surface of the silicon substrate.

[0036] 4. In summary, this utility model optimizes the grid structure by combining strip-shaped contact sub-grids with strip-shaped non-contact channel induced electrodes to improve the surface sheet resistance, grid resistance, and surface field effect passivation of solar cells. This reduces the loss of carrier lateral transport and avoids the increase in Auger recombination and the reduction in passivation effect caused by high-concentration doping. As a result, it further improves the fill factor, open-circuit voltage, and conversion efficiency of solar cells, and simplifies the process and reduces costs. Attached Figure Description

[0037] Figure 1 This is a top view of the grid line structure in Examples 1-2, where the non-contact grid lines are parallel to the contact sub-grids.

[0038] Figure 2This is a cross-sectional view of the grid line structure in Examples 1-2, where the non-contact grid line is parallel to the contact sub-grid.

[0039] Figure 3 This is a cross-sectional view of the grid line structure in Comparative Example 2, where the non-contact grid line covers a single contact sub-grid intersection.

[0040] Figure 4 This is a top view of the grid structure in Embodiment 3, where the non-contact grid line intersects with the contact sub-grid.

[0041] Figure 5 This is a cross-sectional view of the grid structure where the non-contact grid line and the contact sub-grid intersect in Example 3.

[0042] Figure 6 This is a cross-sectional view of the grid line structure where the non-contact conductive film and the contact sub-grid intersect in Example 5.

[0043] Figure 7 This is a top view of the grid structure in Example 4, where the non-contact grid lines and the contact sub-grids both intersect and run parallel.

[0044] Figure 8 This is a cross-sectional view of the grid structure in Example 4, where the non-contact grid lines and the contact sub-grids are both intersecting and parallel.

[0045] Reference numerals: 1. Main gate; 2. Non-contact channel induction electrode; 21. First non-contact gate line; 22. Second non-contact gate line; 3. Contact sub-gate; 4. Passivation layer; 5. Silicon substrate. Detailed Implementation

[0046] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] One embodiment of the solar cell, see [link to example]. Figures 1-2 It includes a silicon substrate 5 and a passivation layer 4 and a grid structure sequentially disposed on the surface of the silicon substrate 5. In practice, the solar cell can be a gridless cell or a cell with a grid; when the solar cell is a gridless cell, solder ribbons can be used instead of the grid 1 to collect current.

[0049] In this embodiment, the solar cell is a grid cell, and the grid structure is one type of grid structure shown below.

[0050] Specifically, the solar cell in this embodiment is preferably a TOPCon cell. The other structures of the TOPCon cell are the same as those of existing TOPCon cells, and therefore will not be described in detail.

[0051] In practice, the grid structure shown below in this embodiment can be applied to both the front and back sides of a solar cell. However, for cost considerations, in this embodiment, only the back side of the TOPCon solar cell uses the grid structure shown below, while the front side of the TOPCon solar cell does not use the grid structure shown below (the front side of the TOPCon solar cell uses a traditional grid structure consisting of a main grid and sub-grids).

[0052] One grid line structure of this embodiment is shown in [reference]. Figures 1-2 It includes a main gate 1, a contact sub-gate 3, and a non-contact channel induction electrode 2. The main gate 1, the contact sub-gate 3, and the non-contact channel induction electrode 2 are all strip-shaped. Preferably, there are multiple main gates 1. The multiple main gates 1 are arranged along a first direction, and are spaced apart from each other.

[0053] Preferably, there are multiple contact-type sub-gates 3. These multiple contact-type sub-gates 3 are arranged along the second direction and are spaced apart from each other. Each contact-type sub-gate 3 passes through the passivation layer 4 and makes direct ohmic contact with the silicon substrate 5, so that the contact-type sub-gate 3 can be used to collect current from the surface of the silicon substrate 5.

[0054] 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 sub-gate 3 can be made of burn-through metal grid paste.

[0055] Compared with existing segmented line or dot-shaped short gates, the contact-type sub-gate 3 in this embodiment is strip-shaped, which can greatly improve the current collection capability of the entire silicon substrate 5 surface.

[0056] Moreover, each contact sub-grid 3 is in electrical contact with multiple main grids 1 so that the main grids 1 collect the current on the contact sub-grid 3 and transmit the collected current to the output terminal of the solar cell for use by external electrical equipment.

[0057] In this embodiment, the non-contact channel induction electrode 2 is a non-contact grid line; the number of non-contact grid lines can be one or more, preferably multiple. The multiple non-contact grid lines are also arranged along the second direction (such as the x-axis direction), and the multiple non-contact grid lines are spaced apart from each other; each non-contact grid line makes electrical contact with multiple main grids 1.

[0058] In practice, due to cost considerations, the density of non-contact grid lines is less than 1000 lines / cm. The density of non-contact grid lines directly affects the width of the non-contact grid lines and the spacing between them; if the density of non-contact grid lines is too high, the width of the non-contact grid lines will be very small, which is difficult to achieve in terms of manufacturing process, and even if it can be achieved in terms of manufacturing process, the cost will be too high.

[0059] Furthermore, the contact sub-gate 3 and the non-contact gate line are arranged parallel to each other, and the contact sub-gate 3 and the non-contact gate line are arranged alternately, and the contact sub-gate 3 and the non-contact gate line do not contact each other.

[0060] Furthermore, the non-contact gate line is located on the surface of the passivation layer 4, and the non-contact gate line does not make direct ohmic contact with the silicon substrate 5, so that the non-contact gate line can be used to construct a better carrier transport channel.

[0061] In practice, non-contact gate lines can be made using non-burn-through metal gate paste. The material of the non-contact gate line is at least one of silver and base metals (such as copper, aluminum, etc.). The cross-sectional shape of the non-contact gate line is at least one of rectangular (such as square, rectangle), triangular, trapezoidal, and elliptical. In one gate line structure of this embodiment, the conductivity type of the silicon substrate 5 below the non-contact channel induction electrode 2 is the same as the conductivity type of the silicon substrate 5 below the adjacent contact sub-gate 3 (such as N-type or P-type).

[0062] A method for manufacturing a grid wire structure according to this embodiment includes the following manufacturing steps:

[0063] Step 1: Prepare a silicon substrate 5 with a passivation layer 4 on its surface.

[0064] Step 2: Print the main gate paste, contact sub-gate paste and non-contact channel induced electrode paste sequentially on the surface of passivation layer 4.

[0065] Step 3: Sintering to obtain a grid structure comprising the above-mentioned contact sub-grid 3, non-contact grid lines and main grid 1.

[0066] A photovoltaic module according to this embodiment includes a photovoltaic front panel, a battery layer and a photovoltaic back panel stacked sequentially; the battery layer is a solar cell as described above in this embodiment.

[0067] Example 2

[0068] The grid structure, its manufacturing method, and the photovoltaic module of this embodiment are all based on Embodiment 1. The difference between this embodiment and Embodiment 1 is:

[0069] The silicon substrate 5 with passivation layer 4 and its TOPCon cell in this embodiment are from different batches than those in Example 1. Therefore, the performance test results of the TOPCon cell in this embodiment are slightly different from those in Example 1.

[0070] Example 3

[0071] The grid structure and its fabrication method, solar cell, and photovoltaic module of this embodiment are all based on Embodiment 1. The difference between this embodiment and Embodiment 1 is as follows:

[0072] See Figures 4-5 The non-contact channel induction electrode 2 (such as a non-contact grid line) in this embodiment of the grid line structure differs from that in Embodiment 1 in the following ways:

[0073] In the gate structure of this embodiment, multiple non-contact gate lines are arranged along a first direction (such as the y-axis direction), and the multiple non-contact gate lines are spaced apart from each other; each non-contact gate line makes electrical contact with multiple contact sub-gates 3 by intersecting each other (preferably perpendicular to each other), and the side of the contact sub-gate 3 away from the silicon substrate 5 is lower than the side of the non-contact gate line away from the passivation layer 4.

[0074] Moreover, the non-contact grid lines are arranged parallel to the main grid 1, and the non-contact grid lines and the main grid 1 do not contact each other.

[0075] Example 4

[0076] The grid structure and its fabrication method, solar cell, and photovoltaic module of this embodiment are all based on Embodiment 1. The difference between this embodiment and Embodiment 1 is as follows:

[0077] See Figures 7-8 The non-contact channel induction electrode 2 in this embodiment of the grid structure differs from that in Embodiment 1 in the following ways:

[0078] In the grid line structure of this embodiment, the non-contact channel induction electrode 2 includes a first non-contact grid line 21 (corresponding to the first channel induction electrode) and a second non-contact grid line 22 (corresponding to the second channel induction electrode).

[0079] In this configuration, multiple first non-contact grid lines 21 are arranged along a second direction (such as the x-axis direction), thus the first non-contact grid lines 21 and the contact sub-grids 3 are arranged parallel to each other. The specific arrangement of the first non-contact grid lines 21 can be referred to the non-contact grid lines in Embodiment 1.

[0080] In this configuration, multiple second non-contact grid lines 22 are arranged along a first direction (such as the y-axis direction), so each second non-contact grid line 22 makes electrical contact with multiple contact sub-grids 3 by means of mutual crossing (preferably mutual perpendicularity). The specific arrangement of the second non-contact grid lines 22 can be referred to the non-contact grid lines in Embodiment 3.

[0081] Furthermore, the first non-contact grid line 21 and the second non-contact grid line 22 are electrically connected by crossing each other (preferably perpendicular to each other).

[0082] Example 5

[0083] The grid structure and its manufacturing method, solar cell, and photovoltaic module of this embodiment are all based on Embodiment 3. The difference between this embodiment and Embodiment 3 is that:

[0084] See Figure 6 The non-contact channel induction electrode 2 in the grid structure of this embodiment differs from that in embodiment 3 in the following ways:

[0085] In the grid structure of this embodiment, the non-contact channel induction electrode 2 is a non-contact conductive film. This non-contact conductive film can be a non-contact transparent conductive film or a non-contact non-transparent conductive film.

[0086] In practice, primarily due to considerations of manufacturing costs 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 side of the solar cell, an excessively thick film will lead to increased parasitic absorption of light, thereby reducing battery conversion efficiency. Conversely, if the non-contact transparent conductive film is applied to the back side of the solar cell, an excessively thick film will not only increase manufacturing costs but may also cause warping of the solar cell, increasing the defect rate and ultimately raising the overall production cost.

[0087] Non-contact conductive films are metallic conductive films and / or non-metallic conductive films. The material of metallic conductive films is at least one of silver and base metals (such as copper, aluminum, etc.).

[0088] Comparative Example 1

[0089] The grid structure, its fabrication method, and the solar cell in this comparative example are all based on Example 1, but differ from Example 1 in that:

[0090] The grid structure of this comparative example does not have a non-contact channel induction electrode 2. Correspondingly, in the fabrication method of the grid structure of this comparative example, the printing process of the non-contact channel induction electrode paste is omitted in step 2. Therefore, the solar cell of this comparative example is a TOPCon cell that does not use the non-contact channel induction electrode 2.

[0091] Comparative Example 2

[0092] The grid structure, its fabrication method, and the solar cell in this comparative example are all based on Example 2, but differ from Example 2 in that:

[0093] A comparative grid line structure, see [link / reference]. Figure 3 Its non-contact channel induction electrode 2 (such as a non-contact gate line) covers a single contact sub-gate 3 (instead of a gate line structure of 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).

[0094] Comparative Example 3

[0095] The grid structure, its fabrication method, and the solar cell in this comparative example are all based on Example 3, but differ from Example 3 in that:

[0096] The grid structure of this comparative example does not have a non-contact channel induction electrode 2. Correspondingly, in the fabrication method of the grid structure of this comparative example, the printing process of the non-contact channel induction electrode paste is omitted in step 2. Therefore, the solar cell of this comparative example is a TOPCon cell that does not use the non-contact channel induction electrode 2.

[0097] Comparative Example 4

[0098] The grid structure, its fabrication method, and the solar cell in this comparative example are all based on Example 4, but differ from Example 4 in that:

[0099] The grid structure of this comparative example does not have a non-contact channel induction electrode 2. Correspondingly, in the fabrication method of the grid structure of this comparative example, the printing process of the non-contact channel induction electrode paste is omitted in step 2. Therefore, the solar cell of this comparative example is a TOPCon cell that does not use the non-contact channel induction electrode 2.

[0100] Performance testing

[0101] 1. Performance tests were conducted on the TOPCon batteries of Example 1 and Comparative Example 1 respectively. The number of TOPCon batteries used for performance testing in Example 1 and Comparative Example 1 was 50 each. After excluding abnormal performance test data and taking the average value, the test results are shown in Table 1 below.

[0102] Table 1

[0103] 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

[0104] 2. Performance tests were conducted on the TOPCon batteries of Example 2 and Comparative Example 2 respectively. The number of TOPCon batteries used for performance testing in Example 2 and Comparative Example 2 was 50 each. After excluding abnormal performance test data and taking the average value, the test results are shown in Table 2 below.

[0105] Table 2

[0106]

[0107]

[0108] 3. Performance tests were conducted on the TOPCon batteries of Example 3 and Comparative Example 3 respectively. The number of TOPCon batteries used for performance testing in Example 3 and Comparative Example 3 was 50 each. After excluding abnormal performance test data and taking the average value, the test results are shown in Table 3 below.

[0109] Table 3

[0110] 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

[0111] 4. Performance tests were conducted on the TOPCon batteries of Example 4 and Comparative Example 4 respectively. The number of TOPCon batteries used for performance testing in Example 4 and Comparative Example 4 was 50 each. After excluding abnormal performance test data and taking the average value, the test results are shown in Table 4 below.

[0112] Table 4

[0113] 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

[0114] In Table 1-4, Eta is the battery conversion efficiency, Voc is the open-circuit voltage, Isc is the short-circuit current, and FF is the fill factor.

[0115] In summary, this invention optimizes the grid structure by combining strip-shaped contact sub-grids with strip-shaped non-contact channel induction electrodes to improve the surface sheet resistance, grid resistance, and surface passivation effect (i.e., field-effect passivation effect on the silicon substrate surface), and reduces carrier lateral transport losses, thereby further improving the fill factor, open-circuit voltage, and conversion efficiency of the solar cell (see Tables 1-4). The non-contact channel induction electrodes can achieve the effects of this invention using some low-cost materials (such as base metals), thus further reducing the production cost and raw material cost of the solar cell.

[0116] The grid structure of this invention uses a combination of strip-shaped contact sub-grids and strip-shaped non-contact channel induced electrodes, instead of the segmented linear or dotted short grids found in existing grid structures. Therefore, the solar cell of this invention does not require high-concentration doping on the silicon substrate surface to obtain an emitter with a high-concentration region. Consequently, the fabrication process of the solar cell of this invention is simpler, and it can effectively avoid the increase in Auger recombination and the reduction in passivation effect caused by high-concentration doping.

[0117] Furthermore, especially when non-contact conductive films are stacked and covered on each contact sub-gate for electrical contact, the non-contact conductive film has a larger area than the non-contact gate line in terms of the area where the present invention can be achieved. Therefore, the gate line structure of Embodiment 5 is superior to the gate line structures of Embodiments 1-3 in terms of realizing the carrier transport channel and the surface field effect passivation of the silicon substrate. Moreover, as Figure 6 The non-contact conductive film shown can also assist in transferring charge carriers collected by the contact sub-grid to the external circuit, thereby reducing the series resistance of the battery. Therefore, the non-contact conductive film has better overall performance than the non-contact grid line.

[0118] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0119] The technical solution provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A grid structure for a solar cell, the solar cell comprising a silicon substrate and a passivation layer and a grid structure sequentially disposed on the surface of the silicon substrate; characterized in that, The gate structure includes a non-contact channel induction electrode and several spaced-apart contact sub-gates. The contact sub-gate and the non-contact channel induction electrode are arranged alternately and parallel to each other so that the contact sub-gate and the non-contact channel induction electrode do not contact each other, and / or, each contact sub-gate is electrically contacted by crossing or stacking with the non-contact channel induction electrode. Both the contact sub-gate and the non-contact channel induction electrode are strip-shaped. The contact sub-gate makes ohmic contact with the silicon substrate after passing through the passivation layer, while the non-contact channel induction 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 induction electrode and the surface of the silicon substrate when the solar cell generates electricity.

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

3. A grid structure for a solar cell according to claim 1 or 2, characterized in that, It also includes several spaced main gates, and the main gates are arranged along a first direction; the non-contact channel induction electrode and the contact sub-gate are arranged along a second direction; the first direction and the second direction intersect each other so that the non-contact channel induction electrode and the contact sub-gate are in electrical contact with the main gate; The number of non-contact channel induction electrodes is multiple, and the multiple non-contact channel induction electrodes are distributed at intervals; the contact sub-gate and the non-contact channel induction electrodes are arranged alternately and parallel to each other, so that the contact sub-gate and the non-contact channel induction electrodes do not come into contact with each other.

4. A grid structure for a solar cell according to claim 1 or 2, characterized in that, The number of non-contact channel induction electrodes is multiple, and the multiple non-contact channel induction electrodes are distributed at intervals and are all arranged along the first direction; while several contact sub-gates are arranged along the second direction, and the first direction and the second direction intersect each other, so that each non-contact channel induction electrode makes electrical contact with several contact sub-gates.

5. The grid structure for a solar cell according to claim 4, characterized in that, The solar cell is a grid cell, and the grid structure further includes several grids spaced apart, and the grids are arranged along a first direction so that the non-contact channel induced electrode is parallel to the grids and does not contact them. Alternatively, the solar cell may be a gridless cell, in which current is collected via external solder strips.

6. A grid structure for a solar cell according to claim 1 or 2, characterized in that, It also includes several spaced main gates, and all of the main gates are arranged along the first direction; The non-contact channel induction electrode includes a first channel induction electrode arranged along the second direction and a second channel induction electrode arranged along the first direction; The plurality of contact sub-gates are arranged along the second direction, and the first direction and the second direction intersect each other, so that the first channel induction electrode and the contact sub-gates are electrically in contact with the main gate, and each second channel induction electrode intersects with the plurality of contact sub-gates to make electrical contact, and the second channel induction electrode also intersects with the first channel induction electrode to make electrical contact. The contact sub-gate and the first channel induction electrode are arranged alternately and parallel to each other, so that the contact sub-gate and the first channel induction electrode do not come into contact with each other.

7. The grid structure for a solar cell according to claim 2, characterized in that, The density of the non-contact grid lines is less than 1000 wires / cm; The cross-sectional shape of the non-contact grid line is at least one of the following: rectangular, triangular, trapezoidal, and elliptical. Non-contact grid lines are silver grid lines and / or base metal grid lines.

8. The grid structure for a solar cell according to claim 2, characterized in that, The non-contact conductive film is either 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, wherein the metal conductive film is a silver conductive film and / or a base metal conductive film.

9. A solar cell, characterized in that, The solar cell is provided with a grid structure for a solar cell as described in any one of claims 1-8 on its front and / or back sides.

10. A photovoltaic module, characterized in that, It includes a photovoltaic front panel, a battery layer, and a photovoltaic back panel stacked sequentially; the battery layer is a solar cell as described in claim 9.

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