Carrier film

Abstract

The utility model belongs to the field of photovoltaic technology, and discloses a carrier film. The carrier film comprises a carrier film body, a groove is formed in the surface of one side of the carrier film body, and the groove comprises a first groove body and a second groove body. The bottom surface of the first groove body is the bottom surface of the groove, and the cross sectional area of the first groove body is gradually increased in the first direction; the second groove body is communicated with one side of the first groove body in the first direction, the cross sectional area of the second groove body is gradually increased in the first direction, and the inner side wall of the second groove body is expanded outwards relative to the inner side wall of the first groove body. The grid line can be applied to a laser pattern transfer printing technology for manufacturing the grid line, and on the premise of ensuring the densification of the grid line, the resistance of the grid line is reduced, and the current of the grid line is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, and particularly relates to a carrier film. Background Art

[0002] The PTP (Pattern Transfer Printing) technology is a new non-contact printing technology. In this technology, the required slurry is coated on a specific flexible light-transmitting material, and a high-power laser beam is used for high-speed patterned scanning to transfer the slurry from the flexible light-transmitting material to the surface of the battery to form grid lines.

[0003] The laser transfer printing technology process mainly includes a filling process and a transfer process. In the filling process, the carrier film has grooves, and the slurry is filled into the grooves. In the transfer process, the side of the carrier film filled with the slurry faces the silicon wafer substrate, and the carrier film is irradiated with a laser until the slurry is released onto the surface of the silicon wafer substrate, and finally grid lines are formed on the surface of the silicon wafer substrate.

[0004] In the prior art, when printing to form grid lines, as Figure 1 shown, the carrier film is generally provided with trapezoidal grooves 10 with a trapezoidal cross-section. The trapezoidal grooves 10 finally form trapezoidal grid lines.

[0005] The trapezoidal grid lines formed by the PTP technology are generally relatively thin. Although it can make the grid lines finer, it also leads to an increase in grid line resistance and a decrease in current, affecting the power generation efficiency of the photovoltaic cell. Content of the Utility Model

[0006] The purpose of the utility model is to provide a carrier film, which can be applied to the laser pattern transfer printing technology for making grid lines, and can reduce the grid line resistance and increase the grid line current on the premise of ensuring the fineness of the grid lines.

[0007] To achieve this purpose, the utility model adopts the following technical solutions:

[0008] A carrier film, including a carrier film body, wherein a groove is provided on one side surface of the carrier film body, and the groove includes:

[0009] A first groove body, the bottom surface of the first groove body is the bottom surface of the groove, and along a first direction, the cross-sectional area of the first groove body gradually increases;

[0010] A second groove body, which is connected to one side of the first groove body along the first direction, and along the first direction, the cross-sectional area of the second groove body gradually increases, and the inner side wall of the second groove body expands outward relative to the inner side wall of the first groove body.

[0011] Optionally, the groove further includes a third groove body, which communicates with the side of the second groove body away from the first groove body. Along the first direction, the cross-sectional area of the third groove body gradually increases, and the inner side wall of the third groove body expands outward relative to the inner side wall of the second groove body.

[0012] Optionally, the minimum cross-sectional area of the third groove body is larger than the maximum cross-sectional area of the second groove body, so that a first step surface is formed at the intersection of the third groove body and the second groove body.

[0013] Optionally, the minimum cross-sectional area of the second groove body is larger than the maximum cross-sectional area of the first groove body, so that a second step surface is formed at the intersection of the second groove body and the first groove body.

[0014] Optionally, the longitudinal cross-sections of the first groove body and the second groove body are both trapezoidal.

[0015] Optionally, the longitudinal cross-sections of the first groove body and the second groove body are both isosceles trapezoids, and the upper base angle of the first groove body is smaller than the upper base angle of the second groove body.

[0016] Optionally, the length of the upper bottom side of the longitudinal cross-section of the first groove body is 4 μm - 26 μm, and the length of the lower bottom side of the longitudinal cross-section of the first groove body is 7 μm - 28 μm.

[0017] Optionally, the length of the upper bottom side of the longitudinal cross-section of the second groove body is 7 μm - 28 μm, and the length of the lower bottom side of the longitudinal cross-section of the second groove body is 8 μm - 30 μm.

[0018] Optionally, the inner side wall of the first groove body is an arc surface; and / or

[0019] the inner side wall of the second groove body is an arc surface.

[0020] Optionally, the material of the carrier film body is a light-transmitting material.

[0021] Advantages of the present utility model:

[0022] For the carrier film proposed by the present utility model, the shape of its groove is set to include a first groove body and a second groove body arranged in sequence along the first direction. The cross-sectional area of the first groove body gradually increases. Along the first direction, the cross-sectional area of the second groove body gradually increases, and the inner side wall of the second groove body expands outward relative to the inner side wall of the first groove body.

[0023] With such a setting, compared with the trapezoidal grooves in the prior art, the presence of the second groove body makes the cross-sectional area of the groove in the present utility model larger; when making grid lines using the groove of the present utility model, on the premise of the same height, the cross-sectional area of the grid line is also larger, that is, the grid line is thicker, thereby reducing the resistance of the grid line and increasing the current. When this grid line is applied to a photovoltaic cell, it can improve the power generation efficiency of the photovoltaic cell.

[0024] Moreover, when making grid lines using the carrier film proposed by the present utility model, due to the setting of the second groove body, the perimeter of the groove becomes longer. When using laser irradiation on the carrier film body to make the grid line in the groove break away from the groove, the required laser power is lower, and the grid line is more likely to break away from the groove; at the same time, when using laser irradiation with a lower power on the carrier film body, it is less likely to disperse the paste of the grid line, reducing the sputtering of the grid line, thereby avoiding the sputtered grid line adhering to the surface of the cell and blocking the surface of the cell, ensuring the power generation efficiency of the cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for description in the embodiments of the present utility model. Obviously, the following described drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the content of the embodiments of the present utility model and these drawings.

[0026] Figure 1 is a schematic diagram of a groove formed on a carrier film in the prior art;

[0027] Figure 2 is a schematic diagram of a groove formed on a carrier film body provided in Embodiment 1 of the present utility model;

[0028] Figure 3 is a schematic diagram of a shape of a groove provided in Embodiment 2 of the present utility model;

[0029] Figure 4 is a schematic diagram of another shape of a groove provided in Embodiment 2 of the present utility model;

[0030] Figure 5 is a schematic diagram of a shape of a groove provided in Embodiment 3 of the present utility model;

[0031] Figure 6 is Figure 5 a schematic diagram of the dimensions of each component in

[0032] Figure 7 is a schematic diagram of another shape of a groove provided in Embodiment 3 of the present utility model;

[0033] Figure 8It is a schematic diagram of the shape of the groove provided in the fourth embodiment of the present utility model.

[0034] Figure 1 In which:

[0035] 10. Trapezoidal groove;

[0036] Figures 2 - 8 In which:

[0037] 1. Carrier film body;

[0038] 2. Groove; 21. First groove body; 22. Second groove body; 23. Third groove body; 24. First step surface; 25. Second step surface. Detailed implementation manners

[0039] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. In addition, it should be noted that for the sake of description, only the parts related to the present utility model are shown in the drawings, rather than all the structures.

[0040] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0041] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0042] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings. They are only for convenience of description and simplifying operations, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0043] Embodiment 1

[0044] Surface metallization is one of the key steps in the preparation of photovoltaic cells. It is a major difficulty affecting the efficiency, cost and performance of photovoltaic cells and plays a crucial role in reducing the cost and improving the efficiency of photovoltaic cells.

[0045] The metallization process is divided into contact type and non-contact type. The contact type is different types of screen printing, and the non-contact type includes laser transfer, electroplating, inkjet printing technology, etc. that are being explored. Considering several technologies comprehensively, laser transfer has more advantages in saving silver paste, improving efficiency and reducing the fragmentation rate.

[0046] Laser graphic transfer technology is a new type of non-contact printing technology. In this technology, the required slurry is coated on a specific flexible light-transmitting material, and a high-power laser beam is used for high-speed graphic scanning to transfer the slurry from the flexible light-transmitting material to the surface of the battery to form grid lines.

[0047] By improving the fine grid printing process of high-efficiency solar cells through non-contact laser printing technology (PTP), the line width limit of traditional screen printing can be broken through, and ultra-fine grid lines with a larger aspect ratio can be printed on the silicon wafer of the battery chip, helping the battery to achieve an ultra-fine grid battery, matching the selective emitter technology, improving the efficiency of the solar cell while significantly saving the slurry consumption by more than 20%, and ultimately reducing the battery production and power generation costs.

[0048] In order to avoid an increase in grid line resistance while achieving grid line fineness, this embodiment provides a carrier film and designs the grooves of the carrier film.

[0049] Specifically, referring to Figure 2 , in this embodiment, the carrier film includes a carrier film body 1, and a groove 2 is provided on one side surface of the carrier film body 1.

[0050] The groove 2 includes a first groove body 21 and a second groove body 22.

[0051] The bottom surface of the first groove body 21 is the bottom surface of the groove 2. Along the first direction, the cross-sectional area of the first groove body 21 gradually increases.

[0052] The second groove body 22 communicates with one side of the first groove body 21 along the first direction. Along the first direction, the cross-sectional area of the second groove body 22 gradually increases, and the inner side wall of the second groove body 22 expands outward relative to the inner side wall of the first groove body 21.

[0053] The inner side wall of the second groove body 22 expands outward relative to the inner side wall of the first groove body 21. With such a setting, the cross-sectional area of the second groove body 22 forms a sudden change relative to the cross-sectional area of the first groove body 21 and shows an increasing trend. When filling the groove 2 with a filler to form a grid line, the grid line can be made thicker, thereby reducing the grid line resistance.

[0054] Specifically, referring to Figure 2 , in this embodiment, the first direction is the thickness direction of the carrier film body 1.

[0055] Along the second direction perpendicular to the first direction (i.e., the length direction of the carrier film body 1), a plurality of grooves 2 are spacedly arranged on the carrier film body 1 to be able to form a plurality of grid lines.

[0056] Specifically, the cross-section parallel to the second direction and perpendicular to the first direction is the cross-section of the groove 2.

[0057] When the carrier film proposed by the present utility model is in use, during the filling process, the slurry for making the grid line is filled into the groove 2; during the transfer, the carrier film body 1 is placed flat and the open end of the second groove body 22 (i.e., Figure 2 the upper side in is oriented towards the silicon wafer. The carrier film body 1 is irradiated with a laser. The energy of the laser is first absorbed by the surface of the slurry, and the generated heat energy vaporizes the organic components in the interface region between the slurry and the groove 2, and a high-pressure steam layer is formed at the interface between the slurry and the carrier film body 1. When sufficient pressure is established at the interface between the slurry and the carrier film body 1, the slurry will be released onto the surface of the silicon wafer and form a grid line on the surface of the silicon wafer.

[0058] For the carrier film proposed by the present utility model, the shape of its groove 2 is set to include a first groove body 21 and a second groove body 22 arranged in sequence along the first direction. The cross-sectional area of the first groove body 21 gradually increases. Along the first direction, the cross-sectional area of the second groove body 22 gradually increases, and the inner side wall of the second groove body 22 expands outward relative to the inner side wall of the first groove body 21.

[0059] With such a setting, compared with the trapezoidal groove in the prior art, the presence of the second groove body 22 makes the cross-sectional area of the groove 2 in this embodiment larger. While increasing the cross-sectional area of the groove 2, the longitudinal cross-sectional area of the groove 2 also becomes larger. When using the groove of this embodiment to make a grid line, on the premise of the same height, the cross-sectional area of the grid line is also larger, that is, the grid line is thicker, thereby reducing the resistance of the grid line and increasing the current. When this grid line is applied to a photovoltaic cell, it can improve the power generation efficiency of the photovoltaic cell.

[0060] When making the gate line using the carrier film proposed in this embodiment, due to the setting of the second groove body 22, the perimeter of the groove 2 becomes longer. When using laser irradiation on the carrier film body 1 to separate the gate line in the groove 2, the required laser power is lower, and the gate line is more likely to separate from the groove. At the same time, when using a lower-power laser to irradiate the carrier film body 1, it is less likely to disperse the paste of the gate line, reducing the sputtering of the gate line, thereby avoiding the sputtered gate line from adhering to the surface of the battery cell and blocking the surface of the battery cell, ensuring the power generation efficiency of the battery cell.

[0061] At the same time, compared with the trapezoidal groove in the prior art, in this embodiment, since the inner side wall of the second groove body 22 expands relative to the inner side wall of the first groove body 21, thus, the bottom cross-sectional area of the paste transferred to the silicon wafer is larger, the bottom is more stable, not easily collapsed, ensuring the height of the gate line, reducing the resistance of the gate line, increasing the current, and thereby improving the battery efficiency.

[0062] Specifically, in this embodiment, the material of the carrier film body 1 is a light-transmitting material.

[0063] Embodiment Two

[0064] This embodiment provides a carrier film, which further improves the carrier film on the basis of Embodiment One.

[0065] Specifically, in this embodiment, the components that are the same as or corresponding to those in Embodiment One adopt the corresponding reference numerals in Embodiment One.

[0066] Specifically, referring to Figure 3 and Figure 4 , in this embodiment, the longitudinal cross-sections (i.e., the cross-section along the thickness direction of the carrier film body 1) of the first groove body 21 and the second groove body 22 are both trapezoidal. The trapezoidal first groove body 21 and second groove body 22 are convenient for processing.

[0067] Furthermore, the longitudinal cross-sections of the first groove body 21 and the second groove body 22 are both isosceles trapezoids, and the upper base angle of the first groove body 21 is smaller than the upper base angle of the second groove body 22.

[0068] The longitudinal cross-sections of the first groove body 21 and the second groove body 22 are both isosceles trapezoids, which is convenient for the paste in the groove 2 to smoothly separate from the groove and transfer to the silicon wafer.

[0069] The upper base angle of the first groove body 21 is smaller than the upper base angle of the second groove body 22. With such a setting, taking the orientation shown in Figure 3 as an example, the inner side surface of the second groove body 22 expands relative to the first groove body 21. On the premise of ensuring the densification of the gate line, the cross-sectional area size of the gate line is increased, the resistance of the gate line is reduced, the current is increased, and thereby the battery efficiency is improved. The existence of the second groove body 22 can avoid the collapse of the gate line to ensure the height of the gate line after the gate line is formed.

[0070] Optionally, the length of the upper base of the longitudinal section of the first groove 21 is 4 μm - 26 μm, and the length of the lower base of the longitudinal section of the first groove 21 is 7 μm - 28 μm.

[0071] The length of the upper base of the longitudinal section of the second groove 22 is 7 μm - 28 μm, and the length of the lower base of the longitudinal section of the second groove 22 is 8 μm - 30 μm.

[0072] A trapezoid is a quadrilateral with only one pair of opposite sides parallel. The parallel sides are called the bases of the trapezoid: the longer base is called the lower base, the shorter base is called the upper base; the other two sides are called the waists.

[0073] Exemplarily, referring to Figure 3 , Figure 3 in which the length of the upper base of the longitudinal section of the first groove 21 is represented by dimension a, and a is 4 μm - 26 μm; exemplarily, a is 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm or 26 μm. Of course, in other embodiments, a can also be selected as other values, which are not limited here too much.

[0074] Figure 3 in which the length of the lower base of the longitudinal section of the first groove 21 is represented by dimension b, and b is 7 μm - 28 μm. Exemplarily, b is 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 21 μm, 23 μm, 25 μm, 27 μm or 28 μm. Of course, in other embodiments, b can also be selected as other values, which are not limited here too much.

[0075] Figure 3 in, the length of the upper base of the longitudinal section of the second groove 22 is also b.

[0076] Figure 3 in, the length of the lower base of the longitudinal section of the second groove 22 is represented by dimension c, and c is 8 μm - 30 μm. Exemplarily, c is 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm. Of course, in other embodiments, c can also be selected as other values, which are not limited here too much.

[0077] Figure 3Among them, the upper base angle of the first groove body 21 is represented by an angle α, and the upper base angle of the second groove body 22 is represented by an angle β. Among them, 90° < α < 180°; optionally, α is 100°, 120°, 130°, 140°, 150°, 160° or 170°. 90° < β < 180°; optionally, β is 100°, 120°, 130°, 140°, 150°, 160° or 170°. And α is less than β. Of course, in other embodiments, α and β can also be set to other values as needed, as long as both are obtuse angles and α is less than β.

[0078] Further specifically, in this embodiment, the junction of the first groove body 21 and the second groove body 22 is located at the middle position in the height direction of the groove 2; in this embodiment, a is 10 μm; b is 20 μm; c is 25 μm. With these dimensions, while reducing the processing difficulty of the groove 2, the cross-sectional area of the groove 2 can be increased, thereby reducing the resistance of the grid line formed in the groove 2.

[0079] Specifically, through experimental verification, on the premise of the same grid line height, for the grid line formed by using the groove 2 provided in this embodiment, the resistance of each grid line can be reduced by 0.02 ohms, the current can be increased by 2 milliamperes, and the power generation efficiency can be increased by 0.01%.

[0080] Optionally, the minimum cross-sectional area of the second groove body 22 and the maximum cross-sectional area of the first groove body 21 can be set to Figure 3 the same size as shown, or can also be set to Figure 4 the case of different sizes in.

[0081] See Figure 4 , the minimum cross-sectional area of the second groove body 22 is greater than the maximum cross-sectional area of the first groove body 21, so that a second step surface 25 is formed at the intersection of the second groove body 22 and the first groove body 21. Specifically, the length of the upper bottom edge of the longitudinal section of the second groove body 22 is greater than the length of the lower bottom surface of the longitudinal section of the first groove body 21 to form the second step surface 25.

[0082] The existence of the second step surface 25 can reduce the wet weight of the consumed slurry and save costs on the premise of ensuring that the slurry in the transfer groove 2 is easily separated from the groove 2 when transferring the slurry in the groove 2.

[0083] Embodiment Three

[0084] This embodiment provides a carrier film, which further improves the carrier film on the basis of Embodiment One.

[0085] Specifically, in this embodiment, the components that are the same as or corresponding to those in Embodiment One adopt the corresponding reference numerals in Embodiment One.

[0086] Specifically, seeFigure 5 and Figure 6 In this embodiment, the groove 2 further includes a third groove body 23. The third groove body 23 communicates with one side of the second groove body 22 away from the first groove body 21. Along the first direction, the cross-sectional area of the third groove body 23 gradually increases, and the inner side wall of the third groove body 23 expands outward relative to the inner side wall of the second groove body 22.

[0087] Specifically, referring to Figure 6 , Figure 6 in, the upper bottom edge length of the longitudinal section of the first groove body 21 is represented by the dimension a, and a is 4 μm - 26 μm; exemplarily, a is 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm or 26 μm. Of course, in other embodiments, a can also be selected as other values, which will not be elaborated here.

[0088] Figure 6 in, the lower bottom edge length of the longitudinal section of the first groove body 21 is represented by the dimension b, and b is 5 μm - 28 μm. Exemplarily, b is 5 μm, 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 21 μm, 23 μm, 25 μm, 27 μm or 28 μm. Of course, in other embodiments, b can also be selected as other values, which will not be elaborated here.

[0089] Figure 6 in, the upper bottom edge length of the longitudinal section of the second groove body 22 is also b.

[0090] Figure 6 in, the lower bottom edge length of the longitudinal section of the second groove body 22 is represented by the dimension c, and c is 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 21 μm, 23 μm, 25 μm, 27 μm or 28 μm. Of course, in other embodiments, c can also be selected as other values, which will not be elaborated here.

[0091] Figure 6 in, the upper bottom edge length of the longitudinal section of the third groove body 23 is also c.

[0092] Figure 6 in, the lower bottom edge length of the longitudinal section of the third groove body 23 is represented by the dimension d. d is 8 μm - 30 μm. Exemplarily, c is 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm. Of course, in other embodiments, d can also be selected as other values, which will not be elaborated here.

[0093] Figure 6Among them, the upper base angle of the first groove body 21 is represented by the angle α. The upper base angle of the second groove body 22 is represented by the angle β. The upper base angle of the third groove body 23 is represented by the angle γ.

[0094] Among them, 90° < α < 180°; optionally, α is 100°, 120°, 130°, 140°, 150°, 160° or 170°. 90° < β < 180°; optionally, β is 100°, 120°, 130°, 140°, 150°, 160° or 170°. And α is less than β. Optionally, γ is 100°, 120°, 130°, 140°, 150°, 160° or 170°, and γ is greater than β.

[0095] Of course, in other embodiments, α, β and γ can also be set to other values according to needs, as long as both are obtuse angles and α is less than β, and γ is greater than β.

[0096] Furthermore, referring to Figure 7 , the minimum cross-sectional area of the third groove body 23 is greater than the maximum cross-sectional area of the second groove body 22, so that a first stepped surface 24 is formed at the intersection of the third groove body 23 and the second groove body 22. The minimum cross-sectional area of the second groove body 22 is greater than the maximum cross-sectional area of the first groove body 21, so that a second stepped surface 25 is formed at the intersection of the second groove body 22 and the first groove body 21.

[0097] The existence of the first stepped surface 24 and the second stepped surface 25 can reduce the wet weight of the consumed slurry and save costs on the premise that the slurry in the transfer groove 2 can easily break away from the groove while ensuring the slurry in the groove 2.

[0098] Embodiment 4

[0099] This embodiment provides a carrier film; on the basis of Embodiment 1, the carrier film is further improved.

[0100] Specifically, referring to Figure 8 , in this embodiment, the inner side wall of the first groove body 21 is an arc surface; and / or

[0101] the inner side wall of the second groove body 22 is an arc surface.

[0102] More specifically, in this embodiment, the inner side wall of the first groove body 21 is an arc surface, and at the same time, the inner side wall of the second groove body 22 is an arc surface.

[0103] Compared with a plane, the inner side wall of the second groove body 22 is an arc surface and the inner side wall of the second groove body 22 is an arc surface, which can further increase the area of the longitudinal section of the groove 2, and then increase the cross-sectional area of the gate line formed in the groove 2, making the gate line thicker and the resistance smaller.

[0104] When the carrier film proposed by the present utility model is in use, during the filling process, the paste for making grid lines is filled into the groove 2; during the transfer, the carrier film body 1 is placed flat and the open end of the second groove body 22 (i.e., Figure 2 the upper side in is oriented towards the silicon wafer. The carrier film body 1 is irradiated with a laser. The energy of the laser is first absorbed by the surface of the paste, and the generated heat energy vaporizes the organic components in the interface region between the paste and the groove 2, and a high-pressure steam layer is formed at the interface between the paste and the carrier film body 1. When sufficient pressure is established at the interface between the paste and the carrier film body 1, the paste will be released onto the surface of the silicon wafer and form grid lines on the surface of the silicon wafer.

[0105] For the carrier film proposed by the present utility model, the shape of its groove 2 is set to include a first groove body 21 and a second groove body 22 arranged in sequence along a first direction. The cross-sectional area of the first groove body 21 gradually increases. Along the first direction, the cross-sectional area of the second groove body 22 gradually increases, and the inner side wall of the second groove body 22 extends outward relative to the inner side wall of the first groove body 21.

[0106] With such a setting, compared with the trapezoidal groove in the prior art, the presence of the second groove body 22 makes the cross-sectional area of the groove 2 in this embodiment larger. While increasing the cross-sectional area of the groove 2, the longitudinal cross-sectional area of the groove 2 also becomes larger. When making grid lines with the groove of this embodiment, on the premise of the same height, the cross-sectional area of the grid lines is also larger, that is, the grid lines are thicker, thereby reducing the resistance of the grid lines and increasing the current. When the grid lines are applied to a photovoltaic cell, it can improve the power generation efficiency of the photovoltaic cell.

[0107] Moreover, when making grid lines with the carrier film proposed by this embodiment, due to the setting of the second groove body 22, the perimeter of the groove 2 becomes longer. When irradiating the carrier film body 1 with a laser to make the grid lines in the groove 2 break away from the groove, the required laser power is lower, and the grid lines are more likely to break away from the groove; at the same time, when irradiating the carrier film body 1 with a laser of a lower power, it is less likely to disperse the paste of the grid lines, reducing the sputtering of the grid lines, thereby avoiding the sputtered grid lines adhering to the surface of the cell and blocking the surface of the cell, and ensuring the power generation efficiency of the cell.

[0108] At the same time, compared with the trapezoidal groove in the prior art, in this embodiment, since the inner side wall of the second groove body 22 extends outward relative to the inner side wall of the first groove body 21, thus, the bottom cross-sectional area of the paste transferred to the silicon wafer is larger, the bottom is more stable, not easily collapsed, ensuring the height of the grid lines, reducing the resistance of the grid lines, increasing the current, and thereby improving the cell efficiency.

[0109] Obviously, the above embodiments of the present utility model are merely examples for clearly illustrating the present utility model, rather than limitations on the implementation manners of the present utility model. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present utility model. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the claims of the present utility model.

Claims

1. Carrier membrane, characterized in that, It includes a carrier film body (1), and a groove (2) is provided on one side surface of the carrier film body (1). The groove (2) includes: A first groove body (21), the bottom surface of the first groove body (21) is the bottom surface of the groove (2), and along the first direction, the cross-sectional area of the first groove body (21) gradually increases; A second groove body (22), which is connected to one side of the first groove body (21) along the first direction. Along the first direction, the cross-sectional area of the second groove body (22) gradually increases, and the inner side wall of the second groove body (22) expands outward relative to the inner side wall of the first groove body (21).

2. The carrier film according to claim 1, characterized in that, The groove (2) further includes a third groove body (23), the third groove body (23) is connected to the side of the second groove body (22) away from the first groove body (21). Along the first direction, the cross-sectional area of the third groove body (23) gradually increases, and the inner side wall of the third groove body (23) expands outward relative to the inner side wall of the second groove body (22).

3. The carrier film according to claim 2, wherein The minimum cross-sectional area of the third groove body (23) is greater than the maximum cross-sectional area of the second groove body (22), so that a first step surface (24) is formed at the intersection of the third groove body (23) and the second groove body (22).

4. The carrier film according to claim 1, characterized in that, The minimum cross-sectional area of the second groove body (22) is greater than the maximum cross-sectional area of the first groove body (21), so that a second step surface (25) is formed at the intersection of the second groove body (22) and the first groove body (21).

5. The carrier film according to any one of claims 1-4, characterized in that, The longitudinal sections of the first groove body (21) and the second groove body (22) are both trapezoidal.

6. The carrier film according to claim 5, characterized in that, The longitudinal sections of the first groove body (21) and the second groove body (22) are both isosceles trapezoids, and the upper base angle of the first groove body (21) is smaller than the upper base angle of the second groove body (22).

7. The carrier film according to claim 5, characterized in that, The length of the upper bottom side of the longitudinal section of the first groove body (21) is 4 μm - 26 μm, and the length of the lower bottom side of the longitudinal section of the first groove body (21) is 7 μm - 28 μm.

8. The carrier film according to claim 5, characterized in that, The length of the upper bottom side of the longitudinal section of the second groove body (22) is 7 μm - 28 μm, and the length of the lower bottom side of the longitudinal section of the second groove body (22) is 8 μm - 30 μm.

9. The carrier film according to any one of claims 1-4, characterized in that, The inner side wall of the first groove body (21) is an arc surface; and / or The inner side wall of the second groove body (22) is an arc surface.

10. The carrier membrane according to any one of claims 1-4, characterized in that, The material of the carrier film body (1) is a light-transmitting material.

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