Photovoltaic cell

Abstract

The utility model discloses a photovoltaic cell. The photovoltaic cell comprises a cell body and a plurality of fine grid lines matched on the surface of the cell body, the fine grid lines adopt metal wires; the diameter of each thin grid line is less than or equal to 20 microns, the number density of the thin grid lines in the unit length direction is 5-15 / cm, each thin grid line is fixed on the surface of the battery piece body, and the shading rate of all the thin grid lines to the battery piece body is less than or equal to 2.0%. According to the utility model, the shading area of the thin grid lines on the battery piece body is small, the cost is low, and the problem of grid breakage can be effectively prevented.

Description

Technical Field

[0001] The utility model relates to the field of photovoltaic cells, in particular to a photovoltaic cell. Background Art

[0002] Photovoltaic cells (also known as solar chips or photocells) are thin optoelectronic semiconductor sheets that use sunlight to generate electricity directly. The main function of the gate electrode on the surface of the photovoltaic cell is to collect photogenerated carriers and then converge the output current. Figure 1 As shown, the gate electrode on the surface of the photovoltaic cell generally includes a fine grid line B1 for collecting current and a main grid line B2 for collecting current; the fine grid line B1 is generally formed on the surface of the cell body A of the photovoltaic cell by a screen printing process; the screen printing process is specifically as follows:

[0003] Step 1: Place the cell body A under the screen C with the template attached, and the printing paste D is squeezed by the scraper E to pass through the mesh C1 in the middle of the screen C and print on the cell body A; because the template attached to the screen C has a pattern, the template will seal part of the screen holes of the screen C so that the printing paste D cannot pass through, so that only the printing paste corresponding to the pattern part of the template is printed on the cell body A; in short, screen printing is actually printing based on the principle of penetration;

[0004] Step 2: After the printing paste D corresponding to the graphic part of the template is printed on the battery cell body A, it is first dried to volatilize the organic matter in the printing paste D, and then sintered in a sintering furnace at 800°C for about 2 seconds to form a fine grid line B1 for collecting current.

[0005] The existing printing paste D generally uses silver paste, the main components of which are silver powder, glass powder and organic solvent. The cell body A has an aluminum back electrode, a PN junction and a silicon nitride anti-reflection layer; during the sintering process, the silver powder of the silver paste will solidify into a silver electrode, and the organic solvent will react with the silicon nitride anti-reflection layer to generate silicon dioxide and nitrogen, so that the silver electrode is in contact with the PN junction; at the same time, the glass powder will fill the gap of the silver electrode after melting, increasing the stability and conductivity of the fine grid line B1 and the main grid line B2.

[0006] Although the technology of screen printing fine grid lines B1 and main grid lines B2 on the surface of the cell body A through screen printing is widely used, the screen printing process also has certain defects. For example, the body resistance of the silver electrode is large, the generation of silicon dioxide during the sintering process leads to a large contact resistance between the silver electrode and the PN junction, and it is difficult to control the width of the fine grid lines B1 and the thick grid lines B2 by screen printing, resulting in a large shading area of ​​the photovoltaic cell; in addition, due to the small width of the fine grid lines B1 on the photovoltaic cell, the fine grid lines B1 formed by screen printing are easy to break, forming a broken grid and affecting the extraction of current; and due to the precious metal characteristics of silver powder and the processing particle size requirements, as well as the specific requirements of silver powder in terms of fluid storage and transportation, the price of silver powder remains high, which restricts the manufacturing cost of photovoltaic cells, making it difficult to reduce the manufacturing cost of photovoltaic cells, and affecting the universal application of photovoltaic cells.

[0007] In view of the existence of the above problems, it is necessary to develop a photovoltaic cell that can reduce the shading area of ​​the thin grid lines to the cell body and effectively prevent the problem of broken grids. Utility Model Content

[0008] The utility model aims to provide a photovoltaic cell sheet, which can reduce the light shielding area of ​​the cell sheet body caused by the thin grid lines and effectively prevent the problem of grid breakage.

[0009] In order to achieve the above purpose, the solution of the utility model is:

[0010] A photovoltaic cell comprises a cell body and a plurality of fine grid lines matched to the surface of the cell body; the fine grid lines are made of metal wires; the width of the fine grid lines is less than or equal to 20 um, and the density of the number of the fine grid lines is 5 to 15 grid lines / cm; each fine grid line is fixed to the surface of the cell body, and the shading rate of all the fine grid lines to the cell body is less than or equal to 2.0%.

[0011] The metal wire used for the fine grid line is copper wire, silver wire, aluminum wire, nickel wire or alloy metal wire.

[0012] The fine grid lines are metal wires with a plated surface.

[0013] The plating layer is a silver plating layer, a tin plating layer or a nickel plating layer; the metal wire is a copper wire, a silver wire, an aluminum wire, a nickel wire or an alloy metal wire.

[0014] The electrical conductivity of the fine grid line is less than or equal to 9.0×10 -6 Ω·m; the width of the fine grid lines is less than or equal to 15um; the number density of the fine grid lines is 6-10 / cm; the shading rate of all the fine grid lines to the battery cell body is less than or equal to 1.5%.

[0015] The photovoltaic cell sheet further comprises a plurality of main grid lines matched to the surface of the cell sheet body, and the main grid lines and the fine grid lines are arranged crosswise.

[0016] The photovoltaic cell sheet further comprises a transparent photovoltaic film connected to the surface of the cell sheet body, and the transparent photovoltaic film covers each fine grid line.

[0017] The material of the transparent photovoltaic film is EVA or POE.

[0018] The transparent photovoltaic film completely covers the fine grid lines or partially covers the fine grid lines.

[0019] After adopting the above scheme, the fine grid lines of the utility model adopt metal wires, so that the fine grid lines have a certain strength and are not easy to break, thereby preventing the problem of broken grid lines during the manufacturing and use of the fine grid lines; moreover, compared with the existing method of manufacturing fine grid lines through silk screen printing, the fine grid lines of the utility model adopt metal wires and can effectively reduce the amount of silver paste, which helps to reduce the production cost of photovoltaic cells; in addition, the diameter of the metal wire is easy to adjust by stretching, so that the diameter of the fine grid lines of the utility model can be less than or equal to 20um, or even less than or equal to 15um, so that the thin grid lines have a small shielding area on the cell body, which helps to improve the power generation efficiency of the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the manufacturing process of existing photovoltaic cells.

[0021] Figure 2 It is a schematic structural diagram of the photovoltaic cell of the utility model.

[0022] Figure 3 This is a schematic diagram of manufacturing a photovoltaic cell sheet according to the first embodiment of the utility model.

[0023] Figure 4 It is a cross-sectional view of the photovoltaic cell sheet of the first embodiment of the utility model.

[0024] Figure 5 This is a schematic diagram of manufacturing a photovoltaic cell according to the second embodiment of the present utility model.

[0025] Figure 6 It is a cross-sectional view of the photovoltaic cell of the second embodiment of the present utility model.

[0026] Figure 7 The cross section of the fine grid line of the second embodiment of the utility model Figure 1 .

[0027] Figure 8 The cross section of the fine grid line of the second embodiment of the utility model Figure 2 .

[0028] Fig. 9 Schematic diagram of manufacturing fine grid lines in the second embodiment of the present invention Figure 1 .

[0029] Fig.10 Schematic diagram of manufacturing fine grid lines in the second embodiment of the present invention Figure 2 .

[0030] Fig.11 This is a schematic diagram of manufacturing a photovoltaic cell according to the third embodiment of the present utility model.

[0031] Fig.12 This is a schematic diagram of manufacturing a photovoltaic cell according to the fourth embodiment of the utility model.

[0032] Fig.13 It is a cross-sectional view of a photovoltaic cell according to the fourth embodiment of the present utility model.

[0033] Fig.14 This is a schematic diagram of manufacturing a photovoltaic cell according to the fifth embodiment of the present utility model.

[0034] Fig.15 It is a cross-sectional view of the photovoltaic cell of the fifth embodiment of the present utility model.

[0035] Fig.16 This is a schematic structural diagram of a photovoltaic cell according to the sixth embodiment of the utility model.

[0036] Fig.17 This is a cross-sectional view of a photovoltaic cell according to the sixth embodiment of the present utility model.

[0037] Fig.18 This is a schematic diagram of manufacturing a photovoltaic cell according to the sixth embodiment of the utility model.

[0038] Fig.19 This is a schematic diagram of manufacturing a photovoltaic cell according to the seventh embodiment of the utility model.

[0039] Fig. 20 This is a cross-sectional view of a photovoltaic cell according to the seventh embodiment of the present utility model.

[0040] Fig.21 This is a schematic diagram of manufacturing a photovoltaic cell according to the eighth embodiment of the present utility model.

[0041] Fig. 22 This is a schematic diagram of manufacturing a photovoltaic cell sheet according to the ninth embodiment of the present utility model.

[0042] Fig.23 This is a schematic diagram of manufacturing a photovoltaic cell according to the tenth embodiment of the utility model.

[0043] Description of the background art: cell body A, fine grid line B1, main grid line B2, screen plate C, mesh C1, printing paste D, scraper E;

[0044] Specific implementation method label explanation: photovoltaic cell a, cell body 1, fine grid line 2, sintered product of silver powder and glass powder 3, mixture of silver powder and glass powder 4, melt tank 5, transfer roller 6, melt pump 7, slit nozzle 8, glass powder 9, transparent photovoltaic film 10, main grid line 11, conductive glue 12. DETAILED DESCRIPTION

[0045] like Figures 2 to 23 As shown, the utility model discloses a photovoltaic cell a, comprising a cell body 1 and a plurality of fine grid lines 2 matched with the surface of the cell body 1; wherein the fine grid lines 2 are made of metal wires; the width of the fine grid lines 2 is less than or equal to 20 um and the resistivity of the fine grid lines 2 is less than or equal to 9.0×10 -6 Ω·m; each fine grid line 2 is fixed on the surface of the cell body 1, the number density of the fine grid lines 2 is 5-15 / cm, and the shading rate of all the fine grid lines 2 to the cell body 1 is less than or equal to 2.0%. Preferably, the conductivity of the fine grid lines 2 is less than or equal to 9.0×10 -7 Ω·m, the width of the fine grid lines 2 is less than or equal to 15um; the density of the number of the fine grid lines 2 is 6-10 / cm, and the light shielding rate of all the fine grid lines 2 to the battery cell body 1 is less than or equal to 1.5%. The density of the fine grid lines 2 is the number of fine grid lines per centimeter.

[0046] In the utility model, since the fine grid line 2 of the utility model adopts metal wire, the fine grid line 2 has a certain strength and is not easy to break, thereby preventing the fine grid line 2 from breaking during the manufacturing and use process; moreover, compared with the existing method of manufacturing the fine grid line 2 by silk screen printing, the fine grid line 2 of the utility model adopts metal wire and can effectively reduce the amount of silver paste, which helps to reduce the production cost of the photovoltaic cell a; in addition, the width of the metal wire is easy to adjust by stretching, so that the diameter of the fine grid line 2 of the utility model can be less than or equal to 20um, so that the thin grid line 2 has a small shielding area on the cell body 1, which helps to improve the power generation efficiency of the photovoltaic cell a. Among them, the fine grid lines 2 of the utility model are metal wires with a width less than or equal to 20um, while the width of the conventional fine grid lines 2 printed by silver paste is 20~28μm, or even 25-35um; taking a photovoltaic cell a with a side length of 182mm, 170 fine grid lines 2, and a distance between adjacent fine grid lines 2 of 1.08mm as an example, if the fine grid lines 2 printed by silver paste are used and the width of the fine grid lines 2 is 25um, the shading rate of all the fine grid lines 2 to the cell body 1 is 2.3%, while when the fine grid lines 2 in the present application are used, the width of the fine grid lines 2 is selected to be 18um, and the shading rate of all the fine grid lines 2 to the cell body 1 is only 1.7%.

[0047] In the utility model, the metal wire used in the fine grid line 2 can be a copper wire, a silver wire, an aluminum wire, a nickel wire or an alloy metal wire, and the surface of the metal wire can be plated with a coating as needed (the fine grid line 2 uses a metal wire with a coating on the surface), and the coating can be a silver coating, a tin coating or a nickel coating. The surface of the fine grid line 2 can also be fully or partially coated with a mixture 4 of silver powder and glass powder. The cross-section of the fine grid line 2 can be circular, elliptical, triangular or polygonal, and the shape is not limited. Multiple fine grid lines 2 can be distributed parallel to each other, or they can be distributed crosswise with each other.

[0048] The method for measuring the conductivity of the thin grid line 2 is as follows: using a screw micrometer to measure the diameter of the thin grid line 2 at multiple different positions, and obtaining the average diameter D of the thin grid line 2; using the voltammetry method to measure the average resistance value R of the thin grid line 2; using a ruler to measure the effective length of the thin grid line 2 connected to the voltammetry circuit for multiple times, and obtaining the average effective length L of the thin grid line 2; finally, according to the formula ρ=R·(π·D 2 ) / (4·L) to calculate the conductivity ρ of the thin grid line 2.

[0049] The method for measuring the width of the fine grid line 2 is: use an ultra-depth of field 3D digital microscope (the model may be KEYENCE VHX-6000) to photograph multiple fine grid lines 2, and then use the measurement software of the ultra-depth of field 3D digital microscope to measure the image of the fine grid line 2, measure the maximum width on the fine grid line 2 as the width of the fine grid line, measure 5 groups, and average the measured widths of the fine grid lines to obtain the final width W of the fine grid line.

[0050] The method for measuring the shading rate of the fine grid line 2 is: use an ultra-depth 3D digital microscope (the model may be KEYENCE VHX-6000) to measure the diameter W of the fine grid line 2 and the spacing P between adjacent fine grid lines 2, and then calculate the shading rate f of the fine grid line 2 according to the formula f=W / P·100%.

[0051] In order to further explain the technical solution of the present utility model, the present utility model is described in detail below through specific embodiments.

[0052] Embodiment 1:

[0053] Cooperate Figure 3 and Figure 4 As shown, in the first embodiment of the present utility model, the method for laying out the fine grid lines 2 of a photovoltaic cell a comprises: first, laying out a plurality of fine grid lines 2 on the surface of the cell body 1, the fine grid lines 2 are made of metal wires, and while the fine grid lines 2 are laid out on the surface of the cell body 1, the contact between the fine grid lines 2 and the cell body 1 is irradiated with a laser, so that the contact between the fine grid lines 2 and the cell body 1 is melted; then, the fine grid lines 2 are squeezed by a pressure roller, so that the fine grid lines 2 are pressed together with the cell body 1. The utility model can laser weld the fine grid lines 2 and the cell body 1 through the method for laying out the fine grid lines 2 of the photovoltaic cell a, and the use of a pressure roller to squeeze the fine grid lines 2 can effectively ensure that the fine grid lines 2 and the cell body 1 are firmly welded.

[0054] In the first embodiment of the present invention, the present invention can lay multiple fine grid lines 2 on the surface of the battery cell body 1 by unwinding multiple rolls of metal wires; the present invention can also lay multiple fine grid lines 2 on the surface of the battery cell body 1 by unwinding a roll of metal wires having multiple metal wires. In addition, when laying multiple fine grid lines 2 in parallel on the surface of the battery cell body 1, the present invention can position each fine grid line 2 by a wire separator, thereby preventing the fine grid lines 2 from shifting.

[0055] In the first embodiment of the present invention, the parameters of the photovoltaic cell a are: the resistivity ρ of the thin grid line 2 is 1.7×10 -8Ω·m, the width of the fine grid lines 2 is 20 um, the number density of the fine grid lines 2 is 7 / cm, and the shading rate of all the fine grid lines 2 to the battery cell body 1 is 1.2%.

[0056] Embodiment 2:

[0057] Cooperate Figure 5 and Figure 6 As shown, in the second embodiment of the present utility model, the method for arranging fine grid lines 2 of a photovoltaic cell a comprises: first, laying a plurality of fine grid lines 2 on the surface of the cell body 1, the fine grid lines 2 using metal wires, and the surface of the fine grid lines 2 is partially or completely coated with a mixture of silver powder and glass powder 4; then, heating is performed by a tunnel oven or laser irradiation, so that the mixture of silver powder and glass powder 4 coated on the surface of the fine grid lines 2 melts at the contact point between the fine grid lines 2 and the cell body 1; finally, the fine grid lines 2 are squeezed by a pressure roller, so that the fine grid lines 2 are pressed together with the cell body 1, and the melted mixture of silver powder and glass powder 4 is solidified to form a sintered material 3 of silver powder and glass powder, that is, a sintered material 3 of silver powder and glass powder is provided between the fine grid lines 2 and the cell body 1.

[0058] In the second embodiment of the present invention, Figure 7 The surface of the thin grid line 2 is completely covered with a mixture of silver powder and glass powder 4; Figure 8 As shown, the surface of the thin grid line 2 may also be partially covered with a mixture 4 of silver powder and glass powder.

[0059] Cooperate Fig. 9 As shown, a method for combining the fine grid lines 2 with the silver powder and glass powder mixture 4 includes: first, melting the silver powder and glass powder mixture 4 and placing it in a melt tank 5; then, coating the silver powder and glass powder mixture 4 on the entire surface or part of the surface of the fine grid lines 2 through a transfer roller 6, and forming the fine grid lines 2 whose surfaces are fully or partially covered with the silver powder and glass powder mixture 4 after cooling.

[0060] Cooperate Fig.10 Another method for combining the fine grid lines 2 with the silver powder and glass powder mixture 4 includes: first, melting the silver powder and glass powder mixture 4 and placing it in a melt tank 5, then conveying the silver powder and glass powder mixture 4 to a slit nozzle 8 through a melt pump 7, and passing the fine grid lines 2 through the slit nozzle 8 so that the silver powder and glass powder mixture 4 is coated on all or part of the surface of the fine grid lines 2, cooling, and finally forming fine grid lines 2 whose surfaces are all or partially covered with the silver powder and glass powder mixture 4.

[0061] In the second embodiment of the utility model, the surface of the fine grid line 2 is completely or partially coated with a mixture of silver powder and glass powder 4. During the layout process, the surface of the fine grid line 2 can be completely or partially coated with a mixture of silver powder and glass powder 4 to melt by laser irradiation heating or tunnel oven heating. At 400°C to 600°C, the surface glass powder has begun to soften and infiltrate the silver powder, and the silver powder is dissolved in the glass. As the temperature further increases, the glass containing silver begins to erode the silicon matrix inside the cell body 1 and diffuse, that is, the silver on the surface of the fine grid line 2 penetrates the silicon nitride anti-reflection layer on the cell body 1 and contacts the PN junction inside the cell body 1, so that a good ohmic contact is formed between the fine grid line 2 and the cell body 1. At the same time, the glass powder will fill the gaps between the silver powder after melting, increasing the connection stability and conductivity between the fine grid line 2 and the cell body 1.

[0062] In the second embodiment of the present invention, the parameters of the photovoltaic cell a are: the resistivity ρ of the thin grid line 2 is 8.7×10 -7 Ω·m, the width of the fine grid lines 2 is 16 um, the number density of the fine grid lines 2 is 11 / cm, and the shading rate of all the fine grid lines 2 to the battery cell body 1 is 1.6%.

[0063] Embodiment three:

[0064] Cooperate Fig.11 As shown, in the third embodiment of the present utility model, the method for arranging the fine grid lines 2 of a photovoltaic cell a comprises: first, distributing the silver powder and glass powder mixture 4 on the entire cell body 1 or only on the part of the cell body 1 for contacting the fine grid lines 2; then, laying a plurality of fine grid lines 2 on the surface of the cell body 1, wherein the fine grid lines 2 are made of metal wires; then, heating by laser irradiation or tunnel oven to melt the silver powder and glass powder mixture 4; finally, extruding the fine grid lines 2 by a pressure roller so that the fine grid lines 2 are pressed together with the cell body 1, and a sintered material 3 of silver powder and glass powder is present between the fine grid lines 2 and the cell body 1, and removing excess silver powder and glass powder mixture 4 by a suction device.

[0065] In the third embodiment of the utility model, during the layout of the fine grid lines 2, the silver powder and glass powder mixture 4 distributed on the cell body 1 can be melted by heating through a tunnel oven or laser irradiation, and the silver powder is melted in the glass powder and penetrates the silicon nitride anti-reflection layer on the cell body 1, and contacts the PN junction inside the cell body 1, thereby forming a good ohmic contact between the fine grid lines 2 and the cell body 1. At the same time, the glass powder will fill the gaps between the silver powder after melting, increasing the connection stability and conductivity between the fine grid lines 2 and the cell body 1.

[0066] In the third embodiment of the present invention, the thin grid wire 2 can be copper wire, silver wire, aluminum wire, nickel wire, alloy metal wire or metal wire with a plated surface, and no special coating treatment is required, thereby reducing processing difficulty and manufacturing cost.

[0067] In the third embodiment of the present invention, the parameters of the photovoltaic cell a are: the resistivity ρ of the thin grid line 2 is 5.3×10 -6 Ω·m, the width of the fine grid line 2 is 10um, the density of the number of fine grid lines is 15 / cm, and the shading rate of all the fine grid lines 2 to the battery cell body 1 is 1.4%.

[0068] Embodiment 4:

[0069] Cooperate Fig.12 and Fig.13 As shown, in the fourth embodiment of the utility model, the method for laying out the fine grid lines 2 of a photovoltaic cell a comprises: first, laying a plurality of fine grid lines 2 on the surface of the cell body 1, wherein the fine grid lines 2 are made of metal wires; then, adding glass powder 9 between the fine grid lines 2 and the cell body 1, and heating by laser irradiation or tunnel oven, so that the glass powder 9 melts at the contact between the fine grid lines 2 and the cell body 1; finally, squeezing the fine grid lines 2 by a pressing roller, so that the fine grid lines 2 and the cell body 1 are pressed together. . The utility model adds glass powder 9 between the fine grid lines 2 and the cell body 1, so that not only the contact between the fine grid lines 2 and the cell body 1 is melted, but also the glass powder 9 is melted. The melted glass powder 9 can fill the gap between the fine grid lines 2 and the cell body 1, so that the fine grid lines 2 and the cell body 1 form good contact, effectively preventing the delamination of the fine grid lines 2 and the cell body 1, and increasing the connection stability and conductivity of the fine grid lines 2 and the cell body 1. When laser irradiation is used for heating, the laser may be irradiated onto the surface of the laid fine grid lines 2 , or the laser may be irradiated between the fine grid lines 2 and the cell body 1 during the laying process of the fine grid lines 2 .

[0070] In the fourth embodiment of the present invention, the parameters of the photovoltaic cell a are: the resistivity ρ of the thin grid line 2 is 2.8×10 -8 Ω·m, the width of the fine grid lines 2 is 15 um, the number density of the fine grid lines 2 is 9 / cm, and the shading rate of all the fine grid lines 2 to the battery cell body 1 is 1.2%.

[0071] Embodiment five:

[0072] Cooperate Fig.14 and Fig.15As shown, in the fifth embodiment of the present utility model, the method for laying out the fine grid lines 2 of a photovoltaic cell a comprises: first, laying a plurality of fine grid lines 2 on the surface of the cell body 1, wherein the fine grid lines 2 are made of metal wires; then, adding glass powder 9 to the surface of the fine grid lines 2, heating them by a tunnel oven or laser irradiation, so that the glass powder 9 melts and covers the surface of the fine grid lines 2; finally, the fine grid lines 2 are squeezed by a pressure roller, so that the fine grid lines 2 are pressed together with the cell body 1. The utility model adds glass powder 9 to the fine grid lines 2, and the melted glass powder 9 wraps the fine grid lines 2 and then adheres and fixes them together with the cell body 1. Since the glass powder is in a transparent state after solidification, it can wrap the fine grid lines 2 to prevent oxidation and thus improve their stability, and will not affect the shading rate and conductivity.

[0073] In the fifth embodiment of the present invention, the parameters of the photovoltaic cell a are: the resistivity ρ of the thin grid line 2 is 5.8×10 -8 Ω·m, the width of the fine grid lines 2 is 12 um, the number density of the fine grid lines 2 is 12 / cm, and the shading rate of all the fine grid lines 2 to the battery cell body 1 is 1.3%.

[0074] Embodiment six:

[0075] Cooperate Figures 16 to 18 As shown, in the sixth embodiment of the present invention, the photovoltaic cell a also includes a transparent photovoltaic film 10 connected to the surface of the cell body 1, and the transparent photovoltaic film 10 covers each fine grid line 2 and fixes the fine grid line 2 to the surface of the cell body 1; the present invention can fix the fine grid line 2 through the transparent photovoltaic film 10 to effectively prevent the fine grid line 2 from falling off; at the same time, the transparent photovoltaic film 10 can also effectively protect the fine grid line 2, prevent the fine grid line 2 from being directly contacted with the external environment and oxidized, thereby increasing the service life of the photovoltaic cell a. The material of the transparent photovoltaic film 10 can be EVA or POE.

[0076] In the sixth embodiment of the present utility model, a method for laying out the fine grid lines 2 of a photovoltaic cell a comprises: first, laying out a plurality of fine grid lines 2 on the surface of the cell body 1; then, pressing a transparent thermoplastic resin onto the surface of the cell body 1 by a pressing roller, and after the thermoplastic resin is cooled, forming a transparent photovoltaic film 10 covering each fine grid line 2. The method for laying out the fine grid lines 2 of the photovoltaic cell a is simple to operate.

[0077] In the sixth embodiment of the utility model, the utility model uses a pressure roller to press the transparent thermoplastic resin onto the surface of the battery cell body 1 in the following specific manner: firstly, the molten thermoplastic resin is melt-extruded onto the pressure roller, and then the pressure roller is driven to roll on the surface of the battery cell body 1, thereby pressing the thermoplastic resin onto the surface of the battery cell body 1.

[0078] In the sixth embodiment of the utility model, the transparent photovoltaic film 10 can completely cover the fine grid lines 2 or partially cover the fine grid lines 2; when the transparent photovoltaic film 10 completely covers the fine grid lines 2, it can more effectively protect and fix the fine grid lines 2; and when the transparent photovoltaic film 10 partially covers the fine grid lines 2, it can effectively reduce the material used in the transparent photovoltaic film 10 and reduce the cost.

[0079] In the sixth embodiment of the present invention, the parameters of the photovoltaic cell a are as follows: the resistivity of the thin grid line 2 is 5.0×10 -7 Ω·m, the width of the fine grid line 2 is 18um, the number density of the fine grid lines 2 is 10 / cm, and the shading rate of all the fine grid lines 2 to the battery cell body 1 is 1.6%; the fine grid line 2 can be made of copper wire, silver wire, aluminum wire, nickel wire, alloy metal wire or metal wire with a plated surface.

[0080] Embodiment seven:

[0081] Cooperate Fig.19 and Fig. 20 As shown, in the seventh embodiment of the utility model, the photovoltaic cell a also includes a plurality of main grid lines 11 matched with the surface of the cell body 1, the main grid lines 11 are cross-arranged with the fine grid lines 2, the fine grid lines 2 are used to collect current, and the main grid lines 11 are used to collect current, thereby making it easier to derive the current of the cell body 1.

[0082] In the seventh embodiment of the present invention, the fine grid lines 2 can be fixed to the surface of the cell body 1 by gluing, spot welding, laser heating and the laying methods in the above embodiments. The main grid lines 11 can also be made of metal wires, and the main grid lines 11 can be fixed to the surface of the cell body 1 by gluing, spot welding, laser heating and the laying methods in the above embodiments; in addition, the main grid lines 11 can also be fixed to the cell body 1 by screen printing. Specifically, in the seventh embodiment of the present invention, the laying method of the fine grid lines 2 of the photovoltaic cell a includes: first, laying a plurality of fine grid lines 2 on the surface of the cell body 1, and the fine grid lines 2 are made of metal wires; then, laying a plurality of main grid lines 11 crosswise on the surface of the fine grid 2, and the main grid lines 11 are made of metal wires; finally, pressing a transparent thermoplastic resin on the surface of the cell body 1 by a pressing roller, and the thermoplastic resin is cooled to form a transparent photovoltaic film 10 covering each fine grid line and each main grid line 11.

[0083] In the seventh embodiment of the present invention, the parameters of the photovoltaic cell a are as follows: the resistivity of the fine grid line 2 and the main grid line 11 is 1.68×10 -7 Ω·m, the width of the thin grid line 2 is 20 um, the number density of the thin grid lines 2 is 6 / cm, the diameter of the main grid line 11 is 50 um, and the shading rate of all the thin grid lines 2 to the battery cell body 1 is 1.0%.

[0084] Embodiment eight:

[0085] Cooperate Fig.21 As shown, in the eighth embodiment of the utility model, the method for arranging the fine grid lines 2 of a photovoltaic cell a comprises: first, coating a plurality of fine grid lines 2 with a conductive adhesive 13; then, laying each fine grid line 2 on the surface of the cell body 1; finally, curing the conductive adhesive 13 so that the fine grid lines 2 are glued and fixed together with the cell body 1.

[0086] Embodiment nine:

[0087] Cooperate Fig. 22 As shown, in the ninth embodiment of the present utility model, the method for arranging the fine grid lines 2 of a photovoltaic cell a comprises: first, coating the surface of the cell body 1 with a conductive adhesive 13 at a position corresponding to the arrangement of the fine grid lines 2; then, laying each fine grid line 2 on the surface of the cell body 1; finally, curing the conductive adhesive 13 so that the fine grid lines 2 are glued and fixed to the cell body 1.

[0088] Embodiment ten:

[0089] Cooperate Fig.23 As shown, in the tenth embodiment of the present utility model, the method for arranging fine grid lines 2 of a photovoltaic cell a comprises: first, laying a plurality of fine grid lines 2 on the surface of the cell body 1; then, welding the fine grid lines 2 to the cell body 1 by spot welding.

[0090] The above embodiments and drawings do not limit the product form and style of the present utility model. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present utility model.

Claims

1. A photovoltaic cell, comprising a cell body and a plurality of fine grid lines matched to the surface of the cell body; characterized in that: The fine grid lines are made of metal wires; the width of the fine grid lines is less than or equal to 20um, and the density of the number of fine grid lines is 5-15 / cm; each fine grid line is fixed to the surface of the battery cell body, and the shading rate of all fine grid lines to the battery cell body is less than or equal to 2.0%.

2. A photovoltaic cell according to claim 1, characterized in that: The metal wire used for the fine grid line is copper wire, silver wire, aluminum wire, nickel wire or alloy metal wire.

3. A photovoltaic cell according to claim 1, characterized in that: The fine grid lines are metal wires with a plated surface.

4. A photovoltaic cell according to claim 3, characterized in that: The plating layer is a silver plating layer, a tin plating layer or a nickel plating layer; the metal wire is a copper wire, a silver wire, an aluminum wire, a nickel wire or an alloy metal wire.

5. A photovoltaic cell according to claim 1, characterized in that: The electrical conductivity of the fine grid line is less than or equal to 9.0×10 -6 Ω·m; the width of the fine grid lines is less than or equal to 15um; the number density of the fine grid lines is 6-10 / cm; the shading rate of all the fine grid lines to the battery cell body is less than or equal to 1.5%.

6. A photovoltaic cell according to claim 1, characterized in that: It also includes a plurality of main grid lines matched with the surface of the battery cell body, and the main grid lines and the fine grid lines are arranged crosswise.

7. A photovoltaic cell according to claim 1, characterized in that: It also includes a transparent photovoltaic film connected to the surface of the battery cell body, and the transparent photovoltaic film covers each fine grid line.

8. A photovoltaic cell according to claim 7, characterized in that: The material of the transparent photovoltaic film is EVA or POE.

9. A photovoltaic cell according to claim 7, characterized in that: The transparent photovoltaic film completely covers the fine grid lines or partially covers the fine grid lines.

Images