CN112151627B - Double-sided photovoltaic cell, laser cutting method and photovoltaic module - Google Patents
Double-sided photovoltaic cell, laser cutting method and photovoltaic module Download PDFInfo
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- 210000004027 cell Anatomy 0.000 claims abstract description 95
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
- H01L31/022441—Electrode arrangements specially adapted for back-contact solar cells
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/40—Removing material taking account of the properties of the material involved
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/042—PV modules or arrays of single PV cells
- H01L31/05—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells
- H01L31/0504—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells specially adapted for series or parallel connection of solar cells in a module
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Abstract
The invention belongs to the technical field of photovoltaics, and provides a double-sided photovoltaic cell, a laser cutting method and a photovoltaic module. The double-sided photovoltaic cell provided by the invention comprises a cell body, wherein the back surface of the cell body comprises at least two thin grid lines, the back surface of the cell body also comprises at least one metal back field, and the metal back field is arranged between two adjacent thin grid lines. According to the invention, a metal back field is additionally arranged on the back surface of the double-sided photovoltaic cell in the initial region and/or the terminal region of a lossless laser cutting track, so that local metallization protection is formed on a cell. In the process of setting the induction groove on the battery piece through laser firing, the laser firing direction reaches the battery piece through a metal back field, so that damage to the battery piece caused by direct laser firing is avoided, fine cracks are not easily formed on the surface of the battery piece, and the occurrence of edge breakage of a cutting edge or battery piece breakage is reduced.
Description
Technical Field
The invention belongs to the technical field of photovoltaics, and particularly relates to a double-sided photovoltaic cell, a laser cutting method and a photovoltaic module.
Background
As a new battery welding process, the stitch welding technology realizes the superposition of battery pieces on the basis of the traditional welding strip welding process, reduces the space between the battery pieces, and maximizes the utilization area, thereby realizing high energy density. In the manufacturing process of the stitch welding solar module, after the silicon wafers are sorted, the silicon wafers need to be cut and preprocessed, and then the silicon wafers are mutually overlapped and welded by using a flexible welding strip and a customized tool based on a welding technology. The traditional silicon wafer cutting mode is as follows: a trench is scribed in a silicon wafer using a pulsed laser with high energy density and then mechanically broken. The cross section of the silicon wafer cut by the traditional mode is observed by a scanning electron microscope, and the cross section is extremely uneven, is obviously wavy and has more burrs and cracks, because the laser heat causes chemical change of the cut cross section of the battery, the melting phenomenon occurs, and the serious cutting damage is caused to the silicon wafer. Because the intersection point of the laser cutting and the mechanical breaking piece has stress, and the cutting part of the silicon chip is positioned at the rolling position of the welding strip, the quality of the stitch-welded solar module is finally influenced by the damage of the silicon chip caused in the cutting process, and the stitch-welded solar module has more hidden cracks of lines after lamination.
The nondestructive laser cutting is a laser cutting technology of the photovoltaic cell, and the photovoltaic cell is cut into a plurality of pieces by the technology, so that the photovoltaic cell can be further prepared into components such as half pieces, lamination pieces and the like. The main principle of the nondestructive laser cutting is as follows: and heating a certain depth area of the battery piece by using laser, and cooling the surface of the battery piece in time to form an energy difference so that the battery piece is subjected to natural splitting. Compared with the traditional method of physically breaking the cell by cutting the cell by laser, the method has the advantages that the working temperature of nondestructive laser cutting is greatly reduced, and the damage to the cell is reduced.
At present, the double-sided battery is mainly used for nondestructive laser cutting, the double-sided photovoltaic battery is a battery with grid lines uniformly distributed on the front surface and the back surface, and how to further optimize the cutting effect of the nondestructive laser cutting technology on the double-sided photovoltaic battery is a problem expected to be solved by technical personnel in the photovoltaic field.
Disclosure of Invention
The invention aims to provide a double-sided photovoltaic cell, a laser cutting method and a photovoltaic module so as to optimize the cutting effect of a nondestructive laser cutting technology on the double-sided photovoltaic cell.
In order to solve the technical problem, a first aspect of the present invention provides a double-sided photovoltaic cell, including a cell body, where the back of the cell body includes at least two thin gate lines, and the back of the cell body further includes at least one metal back field, where the metal back field is disposed between two adjacent thin gate lines.
A second aspect of the present invention provides a laser cutting method, including: providing the double-sided photovoltaic cell of the first aspect of the invention, setting an induction groove by laser firing with a position of the back surface of the cell body where the metal back field is provided as an initial position, wherein the direction of the laser firing is to reach the cell body through the metal back field, and the length of the induction groove set by the laser firing is greater than or equal to the length of the metal back field in the direction parallel to the thin grid line; and in the region without the metal back field between the two adjacent thin grid lines, carrying out laser heating on the interior of the cell body, and then rapidly cooling the surface of the cell body so as to enable the double-sided photovoltaic cell to crack.
The third aspect of the invention provides a photovoltaic module, which comprises a panel, a first adhesive film, a cell sheet manufactured by the laser cutting method of the second aspect of the invention, a second adhesive film and a back panel, wherein the panel, the first adhesive film, the cell sheet, the second adhesive film and the back panel are sequentially stacked.
Compared with the prior art, the invention has at least the following beneficial effects:
the inventor finds out that the cutting effect of the nondestructive laser cutting technology on the double-sided photovoltaic cell is optimized in the process of searching for the following steps: in the process of carrying out nondestructive laser cutting on the double-sided photovoltaic cell, firstly, laser burning is carried out on a cell slice in an initial area and/or a terminal area of a track to be cut to form an induction groove, and after a natural splitting area of subsequent nondestructive cutting is split, the formed induction groove area is also split. The method for forming the induction groove by the prior laser firing can ensure the straightness of natural splinters in the lossless laser cutting and is also beneficial to the cutting effect. However, in order to form enough energy difference at the natural lobe part to promote the natural lobe to occur, the lobe track of the lossless laser cutting can only be positioned on the silicon substrate between the two grid lines; when the induction groove is formed in the initial area and/or the terminal area of the cutting track by laser burning, the laser burning directly acts on the battery piece, damage is easily caused to the battery piece, in the subsequent natural splitting process, crack diffusion and edge breakage can occur in the induction groove area directly burned by the laser, and the risk of splitting exists.
In contrast, the metal back field is skillfully added to the starting area and/or the ending area of the lossless laser cutting track on the back of the double-sided photovoltaic cell, so that the local metallization protection of the cell is formed. In the process of laser firing and forming the induction groove, the laser firing direction reaches the cell through the metal back field, damage to the cell caused by direct firing of the laser is avoided, fine cracks are not prone to forming on the surface of the cell, the risk of edge breakage or fragment breakage of the split edge in the subsequent natural splitting process is reduced, and the situation that grains of the stitch welding photovoltaic module obtained through further preparation are hidden and cracked after lamination is also obviously reduced. In addition, the metal back field additionally arranged on the back of the double-sided photovoltaic cell is positioned between two adjacent thin grid lines, so that a nondestructive laser cutting track taking the metal back field as a starting area and/or an end area is not overlapped with the grid lines, and a sufficient energy difference can be formed in the nondestructive laser cutting process to promote the double-sided photovoltaic cell to generate natural splintering. In addition, the metal back surface field is prepared on the back surface of the double-sided battery through a screen printing process, and the metal back surface field is firmly bonded with the battery piece through high-temperature sintering; and the metal back surface field is arranged on the back surface of the battery piece, so that the front efficiency of the battery piece is not influenced.
Preferably, in the double-sided photovoltaic cell provided by the invention, the metal back fields are distributed on two opposite sides of the central region of the cell body, so that local metallization protection is simultaneously formed on the starting region and/or the ending region of the lossless laser cutting track.
Preferably, in the double-sided photovoltaic cell provided by the invention, the metal back field extends from the end part of the cell body to the central region, the metal back field extends for a preset distance in a direction parallel to the thin grid line, and a laser firing guide groove is formed in the cell in the preset distance by firing the laser, so that the laser reaches the cell body through the metal back field, and the direct firing of the cell body is avoided.
Preferably, the intersection point of the metal back field and the end of the cell body divides the end of the cell body into 2-6 sections with equal length, so as to meet the cutting requirements of cell pieces with different sizes, such as half cell pieces, three-part cell pieces, six-part cell pieces and the like.
Preferably, in the double-sided photovoltaic cell provided by the invention, the back surface of the cell body further comprises a main grid line, and the main grid line is arranged vertically relative to the fine grid line.
Preferably, in the double-sided photovoltaic cell provided by the invention, the main grid lines and the fine grid lines are silver grid lines, and the metal back field is a silver back field; or the main grid lines and the thin grid lines are aluminum grid lines, and the metal back field is an aluminum back field. When the material of the metal back field is the same as that of the grid lines on the back of the double-sided battery, the metal back field and the grid lines can be formed in one step in screen printing, and the preparation of the grid lines and the metal back field and the stability of the metal back field on the back of the battery piece are facilitated.
Preferably, in the bifacial photovoltaic cell provided by the invention, in a plane where the back surface of the cell body is located: the length of the metal back field in the direction parallel to the thin grid line is 1 mm-2 mm, and the width of the metal back field in the direction perpendicular to the thin grid line is 0.5 mm-1.5 mm. The length and width of the metal back field are in the range provided by the invention, so that the metal back field can be suitable for carrying out conventional screen printing and laser burning processes, and the shielding effect of the metal back field on the back surface of the battery piece can be ignored.
Preferably, in the double-sided photovoltaic cell provided by the invention, the thickness of the metal back field is 10-30 um in the direction perpendicular to the back surface of the cell body, so that the photoelectric conversion efficiency of the cell is not adversely affected, and the screen printing plate ink permeability of the metal back field in the screen printing process can be ensured.
Preferably, in the double-sided photovoltaic cell provided by the invention, the distance between the two thin grid lines with the metal back field arranged at the at least one end part is 1.5 mm-2 mm, and at this time, the width of the metal back field is smaller than or equal to the distance between the thin grid lines, that is, the metal back field is positioned between the two thin grid lines, so that the splitting track of lossless laser cutting is also positioned between the two thin grid lines, and the realization of natural splitting is ensured.
Preferably, in the laser cutting method provided by the present invention, the laser burning uses a pulse laser, and the laser heating uses a continuous laser.
Preferably, in the laser cutting method provided by the invention, a fluid beam is adopted to rapidly cool the surface of the cell body, and the fluid beam is selected from at least one of liquid water, liquid carbon dioxide, liquid hydrogen, liquid nitrogen, low-temperature inert gas, low-temperature carbon dioxide gas, low-temperature hydrogen and low-temperature nitrogen.
Preferably, the photovoltaic module provided by the invention is a half-piece module, a three-piece module, a six-piece module, or a combination thereof. By adjusting the number and the positions of the metal back fields, the cutting requirements of battery pieces with different sizes, such as half battery pieces, three-divided battery pieces, six-divided battery pieces and the like, can be met.
Drawings
Fig. 1 is a schematic diagram of a double-sided photovoltaic cell back grid line without an additional metal back field and a lossless laser cutting track for comparison in a first embodiment;
fig. 2 is a schematic diagram of a double-sided photovoltaic cell back grid line with an additional metal back field, a metal back field, and a lossless laser cutting track in the first embodiment;
fig. 3 is a schematic view of a grid line and a metal back field on the back surface of a double-sided photovoltaic cell with an additional metal back field after nondestructive laser cutting in the first embodiment;
FIG. 4 is a diagram of a double-sided photovoltaic cell back grid line without an added metal back field and a lossless laser cutting trajectory for comparison in a second embodiment;
fig. 5 is a schematic diagram of a double-sided photovoltaic cell back grid line with an additional metal back field, a metal back field, and a lossless laser cutting track in the second embodiment.
Detailed Description
In order that the objects, features and advantages of the present invention can be more clearly understood, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The materials used are not indicated by the manufacturer, and are all conventional products available by commercial purchase. The description of the exemplary embodiments is for exemplary purposes only and is not intended to limit the invention or its applications.
According to a first aspect of the present invention, some embodiments of the present invention provide a double-sided photovoltaic cell, including a cell body, a back surface of the cell body includes at least two thin gate lines, wherein the back surface of the cell body is further provided with at least one metal back field, and the metal back field is disposed between two adjacent thin gate lines.
In some embodiments of the present invention, the metal back fields are distributed on two opposite sides of the central region of the cell body, so as to form local metallization protection for the starting region and/or the ending region of the lossless laser cutting track at the same time.
In some embodiments of the present invention, the metal back field extends from an end portion of the cell body to the central region, and the metal back field extends for a predetermined distance in a direction parallel to the thin grid line.
In some embodiments of the invention, the intersection point of the metal back field and the end of the cell body divides the end of the cell body into 2-6 segments with equal length, so as to meet the cutting requirements of different-size cells such as half cells, three-segment cells, six-segment cells and the like.
In some embodiments of the present invention, the back surface of the battery cell body further includes a main grid line, and the main grid line is perpendicular to the fine grid line.
In some embodiments of the present invention, the main gate lines and the fine gate lines are silver gate lines, and the metal back field is a silver back field. In some embodiments of the present invention, the main gate line and the fine gate line are aluminum gate lines, and the metal back field is an aluminum back field. When the material of the metal back field is the same as that of the grid lines on the back of the double-sided battery, the metal back field and the grid lines can be formed in one step in screen printing, and the preparation of the grid lines and the metal back field and the stability of the metal back field on the back of the battery piece are facilitated.
In some embodiments of the present invention, in a plane of the back surface of the cell body: the length of the metal back field in the direction parallel to the thin grid line is 1 mm-2 mm, and the width of the metal back field in the direction perpendicular to the thin grid line is 0.5 mm-1.5 mm. As an example of some embodiments, the length of the metal back field in a direction parallel to the thin gate line may be 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, etc.; the width of the metal back field in the direction perpendicular to the thin gate line may be 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, or the like. The length and width of the metal back field are preferably within the range provided by the invention by comprehensively considering the error (within 0.3 mm) of the conventional screen printing process and the error (within 0.5 mm) of the conventional laser burning positioning; and the ratio of the shielding area of the metal back field to the back surface of the battery piece is about 4/26550-0.015% (taking the half-cut 10 main grid as an example for calculation), and the shielding effect is almost negligible.
In some embodiments of the invention, the metal back field has a thickness of 10 μm to 30 μm in a direction perpendicular to the back surface of the cell body. As an example of some embodiments, the thickness of the metal back field may be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or the like. In some embodiments of the present invention, the metal back field is a silver back field, and the thickness of the silver back field is preferably 10 to 12 μm. In some embodiments of the present invention, the metal back field is an aluminum back field, and the thickness of the aluminum back field is preferably 20 to 30 μm. The thickness of the metal back field is increased, so that the series resistance of the battery is reduced, and the influence of the additional metal back field on the conversion efficiency of the battery piece can be reduced; however, the excessively high thickness of the metal back field affects the ink permeability of the screen printing plate, so that the surface of the metal back field is in a high-low fluctuation shape, which is not beneficial to protecting the silicon substrate in the laser firing process.
In some embodiments of the present invention, the distance between the two thin gate lines, at least one of which is provided with the metal back field at the end portion, is 1.5mm to 2 mm. As an example of some embodiments, the pitch between two thin grid lines is 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc. When the width of the metal back field is smaller than or equal to the distance between the thin grid lines, namely the metal back field is positioned between the two thin grid lines, the splitting track of the lossless laser cutting is also positioned between the two thin grid lines, and the realization of natural splitting is ensured.
Some embodiments of the present invention also provide a method for preparing a bifacial photovoltaic cell, comprising the steps of: cleaning, texturing, diffusing and secondarily cleaning the silicon wafer; the steps with variable order: depositing a silicon nitride antireflection layer on the front side of the silicon wafer, and depositing an aluminum oxide layer/silicon nitride layer on the back side of the silicon wafer to obtain a cell body; the steps with variable order: preparing a front grid line on the front side of the cell body through screen printing, and preparing a back grid line and a metal back field on the back side of the cell body through screen printing; and sintering to obtain the double-sided photovoltaic cell.
In some embodiments of the present invention, the back gate line and the metal back field are formed in one step in the screen printing process by using the same metal paste, so that the back gate line and the metal back field are fully compatible with existing battery manufacturing processes and equipment.
According to a second aspect of the present invention, an embodiment of the present invention provides a laser cutting method, including: providing the double-sided photovoltaic cell provided by the first aspect of the invention, setting a guiding groove by laser firing with a position of the back surface of the cell body where the metal back field is arranged as an initial position, wherein the direction of the laser firing is to reach the cell body through the metal back field, and the length of the guiding groove set by the laser firing is greater than or equal to the length of the metal back field in the direction parallel to the thin grid line; and in the region without the metal back field between the two adjacent thin grid lines, carrying out laser heating on the interior of the cell body, and then rapidly cooling the surface of the cell body so as to enable the double-sided photovoltaic cell to crack.
In some embodiments of the present invention, the laser firing is performed by using a pulsed laser, and the laser heating is performed by using a continuous laser.
In some embodiments of the present invention, the surface of the cell body is rapidly cooled using a fluid bundle selected from at least one of liquid water, liquid carbon dioxide, liquid hydrogen, liquid nitrogen, low temperature inert gas, low temperature carbon dioxide gas, low temperature hydrogen gas, and low temperature nitrogen gas.
According to a third aspect of the present invention, an embodiment of the present invention further provides a photovoltaic module, where the photovoltaic module includes a panel, a first adhesive film, a cell sheet manufactured by the laser cutting method according to the second aspect of the present invention, a second adhesive film, and a back sheet, which are sequentially stacked.
In some embodiments of the invention, the photovoltaic module is a half-wafer module, a three-wafer module, a six-wafer module, or a combination thereof.
The advantages of the present application are further described below in conjunction with the detailed description. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present application.
In the first embodiment, taking a half-cut 10 as an example of a main grid, the structure and the lossless laser cutting track of the back of a double-sided photovoltaic cell without adding a metal back field and a double-sided photovoltaic cell with adding a metal back field are respectively shown by fig. 1 and fig. 2. In fig. 1 and 2, a solid line in the horizontal direction is a thin grid line on the back of a double-sided photovoltaic cell, a dotted line around a picture is the edge of a cell, and the cell is cut in the middle.
Fig. 1 is a schematic diagram of a double-sided photovoltaic cell back grid line without an additional metal back field and a lossless laser cutting track for comparison in a first embodiment. In fig. 1, a metal back field is not additionally arranged on the back surface of the double-sided photovoltaic cell, and a cutting track 1 is located between two thin grid lines in the middle of a cell piece. In the process of carrying out nondestructive laser cutting on the double-sided battery, in the initial region and the terminal region of a track to be cut, firstly, laser is adopted to burn a battery piece to a certain depth to form an induction groove, and after a natural splitting region of subsequent nondestructive cutting is cracked, the region formed with the induction groove is cracked. However, when the inducing grooves are formed in the initial region and the final region of the cutting track by laser burning, the laser burning directly acts on the battery piece, which is easy to damage the battery piece, and in the subsequent natural splitting process, the slotting region directly burned by the laser can generate crack diffusion and edge breakage, so that the splitting rate is increased.
Fig. 2 is a schematic diagram of a double-sided photovoltaic cell back grid line with an additional metal back field, a metal back field, and a lossless laser cutting track in the first embodiment. In fig. 2, a metal back field 3 is added to the starting area and/or the ending area of a nondestructive laser cutting track 2 on the back surface of a double-sided photovoltaic cell, and local metallization protection is formed on a cell slice. In the process of forming the induction groove by laser firing, the laser firing direction reaches the battery piece through the metal back field, so that the damage of the battery piece caused by the direct firing of the laser is avoided, fine cracks are not easy to form on the surface of the battery piece, and the risk of edge breakage or fragment breakage of the splitting edge in the subsequent natural splitting process is reduced. In addition, the metal back field additionally arranged on the back surface of the double-sided photovoltaic cell is positioned between two adjacent thin grid lines, so that a lossless laser cutting track with the metal back field as a starting area and/or an end area is not overlapped with the thin grid lines, and a sufficient energy difference can be formed in the lossless laser cutting process to promote natural splinters.
Fig. 3 is a schematic diagram of the grid lines and the metal back field on the back surface of the double-sided photovoltaic cell with the metal back field added in the first embodiment after lossless laser cutting. As shown in fig. 3, the double-sided photovoltaic cell with the additional metal back field is cut into two half-cell pieces by lossless laser, a residual metal back field 30 is formed on the back surfaces of the two half-cell pieces, and the residual metal back field 30 is distributed on at least one end of the cut edge of the two half-cell pieces.
In the second embodiment of the present invention, taking three-piece cutting 10 of the main grid as an example, the structure and the lossless laser cutting track of the back side of the double-sided photovoltaic cell without adding the metal back field and the double-sided photovoltaic cell with adding the metal back field are respectively shown by fig. 4 and fig. 5. Fig. 4 is a schematic diagram of a double-sided photovoltaic cell back grid line without an additional metal back field and a lossless laser cutting track for comparison in the second embodiment. In fig. 4, no metal back field is added on the back surface of the double-sided photovoltaic cell, and the cutting track 11 is located between two thin grid lines in the middle of the cell. Fig. 5 is a schematic diagram illustrating a double-sided photovoltaic cell back grid line with an additional metal back field, a metal back field, and a lossless laser cutting track in the second embodiment. In fig. 5, a metal back field 33 is additionally arranged on the back surface of the double-sided photovoltaic cell in the starting region and/or the end region of the lossless laser cutting track 22, so that local metallization protection is formed on the cell, damage to the cell caused by direct firing of laser is avoided, fine cracks are not easily formed on the surface of the cell, the risk of edge breakage or fragment breakage of the split edge in the subsequent natural splitting process is reduced, and the situation that the pattern hidden crack occurs after the stitch welding photovoltaic module is laminated is also obviously reduced. Similarly, the back surfaces of the three battery thirds pieces obtained by cutting in the embodiment also have residual metal back fields, and the residual metal back fields are distributed on at least one end part of the cutting edges of the three battery thirds pieces.
In order to meet the cutting requirements of battery pieces with different sizes, such as half battery pieces, three-part battery pieces, six-part battery pieces and the like, the number and the position of the metal back fields in the embodiment of the invention can be selected in various ways, and are not described one by one.
The above examples are only for illustrating the technical idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (14)
1. A double-sided photovoltaic cell comprises a cell body, wherein the back surface of the cell body comprises at least two thin grid lines, and the double-sided photovoltaic cell is characterized by further comprising at least one metal back field, wherein the metal back field is arranged between two adjacent thin grid lines;
when the double-sided photovoltaic cell is subjected to laser cutting, the position of the back surface of the cell body, which is provided with the metal back surface field, is used as an initial position, and an induction groove is formed by laser firing.
2. The bifacial photovoltaic cell of claim 1, wherein said metal back field is distributed on opposite sides of a central region of said cell body.
3. The bifacial photovoltaic cell of claim 1, wherein the metal back field extends from the ends of the cell body to the central region, and the metal back field extends a predetermined distance in a direction parallel to the thin grid lines.
4. The bifacial photovoltaic cell of claim 1, wherein the intersection of the metal back field with the end of the cell body partitions the end of the cell body into 2-6 segments of equal length.
5. The bifacial photovoltaic cell of claim 1, wherein the back side of the cell body further comprises a bus bar, wherein the bus bar is disposed perpendicular to the fine grid line.
6. The bifacial photovoltaic cell of claim 5, wherein said thin grid lines and said bus bars are silver grid lines and said metal back field is a silver back field; or the thin grid lines and the main grid lines are aluminum grid lines, and the metal back field is an aluminum back field.
7. The bifacial photovoltaic cell of claim 1, wherein, in a plane of the back side of the cell body: the length of the metal back field in the direction parallel to the thin grid line is 1 mm-2 mm, and the width of the metal back field in the direction perpendicular to the thin grid line is 0.5 mm-1.5 mm.
8. The bifacial photovoltaic cell of claim 1, wherein the thickness of the metal back field is between 10um and 30um in a direction perpendicular to the back surface of the cell body.
9. The bifacial photovoltaic cell of claim 1, wherein the spacing between two adjacent thin grid lines is between 1.5mm and 2 mm.
10. A laser cutting method, comprising:
providing the bifacial photovoltaic cell of any one of claims 1 to 9, with a position on the back surface of the cell body where the metal back field is provided as an initial position, opening an induction groove by laser firing, wherein the laser firing direction is to reach the cell body through the metal back field, and the length of the induction groove formed by laser firing is greater than or equal to the length of the metal back field in a direction parallel to the thin grid line;
and in the region without the metal back field between the two adjacent thin grid lines, carrying out laser heating on the interior of the cell body, and then rapidly cooling the surface of the cell body so as to enable the double-sided photovoltaic cell to crack.
11. The laser cutting method according to claim 10, wherein the laser burning is performed by a pulse laser, and the laser heating is performed by a continuous laser.
12. The laser cutting method according to claim 10, wherein the surface of the cell body is rapidly cooled using a fluid beam selected from at least one of liquid water, liquid carbon dioxide, liquid hydrogen, liquid nitrogen, low-temperature inert gas, low-temperature carbon dioxide gas, low-temperature hydrogen gas, and low-temperature nitrogen gas.
13. A photovoltaic module, comprising a panel, a first adhesive film, a cell sheet manufactured by the laser cutting method according to any one of claims 10 to 12, a second adhesive film, and a back sheet, which are sequentially stacked.
14. The photovoltaic module of claim 13, which is a half-sheet module, a three-sheet module, a six-sheet module, or a combination thereof.
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| CN114589413A (en) * | 2022-04-14 | 2022-06-07 | 深圳光远智能装备股份有限公司 | Process method for thermal stress nondestructive scribing of brittle material in photovoltaic industry |
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