Photovoltaic module and production method therefor, and photovoltaic system

Abstract

The present application relates to the field of photovoltaic technology. Provided are a photovoltaic module and a production method therefor, and a photovoltaic system. The photovoltaic module comprises: cells, wherein grid lines are provided on the surfaces of the cells; a bonding layer, which is disposed on the grid lines, wherein the length of each hole in a cross section of the bonding layer is less than or equal to 60% of the dimension of the bonding layer in a direction where the length of the hole is located, and the length of the hole is the maximum dimension of the hole on the cross section of the bonding layer; and electrical interconnection members, which are fixed to the bonding layer, wherein the electrical interconnection members are electrically connected to the grid lines. The dimension of each hole in the bonding layer of the present application is relatively small, thereby ensuring the tensile force of the bonding layer and the electrical interconnection members in the photovoltaic module, and ensuring the quality of the photovoltaic module.

Description

A photovoltaic module, a production method thereof and a photovoltaic system

[0001] The present application claims priority to the Chinese patent application No. 202411388332.1, filed on September 30, 2024, entitled "A photovoltaic module, a production method thereof and a photovoltaic system", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of photovoltaic, in particular to a photovoltaic module, a production method thereof and a photovoltaic system. BACKGROUND

[0003] In the photovoltaic module, the cells are mostly interconnected by using the method of connecting the grid lines with the electrical interconnection pieces through the bonding layer, forming a cell string, and finally forming a photovoltaic module.

[0004] However, in the current photovoltaic module, the grid lines are connected with the electrical interconnection pieces through the bonding layer, and the tensile force is small, the tensile force is unqualified, and the like defects exist, and the problem of the electrical interconnection pieces being separated from the cell sheet is prone to occur in the service process of the photovoltaic module for more than 10 years, affecting the quality and reliability of the photovoltaic module.

[0005] CONTENT

[0006] The present application provides a photovoltaic module and a production method thereof, aiming to solve the problem of poor performance of the photovoltaic module due to the small tensile force of the grid lines connected with the electrical interconnection pieces through the bonding layer.

[0007] In a first aspect, the present application provides a photovoltaic module, comprising:

[0008] a cell sheet, a surface of the cell sheet being provided with a grid line;

[0009] a bonding layer, the bonding layer being arranged on the grid line, a length of a hole in a cross section of the bonding layer being less than or equal to 60% of a size of the bonding layer in a direction in which the length of the hole is located,

[0010] the length of the hole being a maximum size of the hole in the cross section of the bonding layer;

[0011] an electrical interconnection piece, the electrical interconnection piece being fixed on the bonding layer, and the electrical interconnection piece being electrically connected with the grid line.

[0012] In the embodiments of the present application, the length of the hole in the cross section of the bonding layer is less than or equal to 60% of the size of the bonding layer in the direction of the length of the hole. At this time, although there is a hole in the bonding layer for connecting the grid lines and the electrical interconnect, the size of the hole is small, which can ensure the bonding force of the grid lines, the bonding layer and the electrical interconnect at the position of the electrical interconnect of the bonding layer in the photovoltaic module, and the bonding force (peeling strength) is maintained at 1.0 N / mm or more under the conditions of long-term light, water vapor erosion, wind-induced vibration and the like during the service of the photovoltaic module. Furthermore, the small size of the hole is beneficial to the diffusion of the metal elements of the grid lines in the bonding layer, and is beneficial to the stable connection of the bonding layer and the grid lines. In addition, the small size of the hole in the bonding layer can reduce the retention of water vapor in the bonding layer, thereby improving the durability of the bonding layer. At the same time, the process cost and process difficulty can also be considered.

[0013] In some possible embodiments, the length of the hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the length of the hole.

[0014] In some possible embodiments, the width of the hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the width of the hole, and the width direction of the hole in the cross section of the bonding layer is perpendicular to the length direction of the hole.

[0015] In some possible embodiments, the width direction of the hole in the cross section of the bonding layer is perpendicular to the length direction of the hole; and the width of the hole in the cross section of the bonding layer is less than or equal to 80% of the length of the hole.

[0016] In some possible embodiments, the cross-sectional area of the hole in the cross section of the bonding layer is less than or equal to 33% of the cross-sectional area of the bonding layer.

[0017] In some possible embodiments, the cross-sectional area of the hole in the cross section of the bonding layer is less than or equal to 2500 μm 2 .

[0018] In some possible embodiments, the cross section of the bonding layer is a transverse cross section, a longitudinal cross section or an oblique cross section.

[0019] In some possible embodiments, the number of holes in the cross section of the bonding layer is less than or equal to 10.

[0020] In some possible embodiments, the shape of the hole in the cross section of the bonding layer is regular or irregular.

[0021] In some possible embodiments, the cross-sectional area of the largest hole located on the upper surface and the lower surface of the bonding layer is less than the cross-sectional area of the largest hole located inside the bonding layer.

[0022] In some possible embodiments, a connecting portion is arranged on the cell piece, the bonding layer is fixed and electrically connected to the grid line through the connecting portion; on the cell piece, the width of the connecting portion is greater than or equal to the width of the grid line; and the width of the bonding layer is greater than the width of the grid line.

[0023] In some possible embodiments, the electrical interconnect is fixed to the cell piece through a welding process and / or a lamination bonding process.

[0024] In some possible embodiments, a fixing layer is arranged on the electrical interconnect.

[0025] The fixing layer comprises one or more of a fixing film, a fixing tape, insulating glue, and conductive glue.

[0026] In some possible embodiments, the cell piece is a back contact cell piece, at least one side of the bonding layer is provided with an insulating block along the extension direction of the electrical interconnect, and the height difference between the top of the bonding layer and the top of the insulating block is less than or equal to 15 μm.

[0027] In some possible embodiments, the number of electrical interconnects is multiple, the head of at least one electrical interconnect protrudes from the bonding layer, or the head of at least one electrical interconnect is located in the 2 / 3 region of the bonding layer away from the tail of the electrical interconnect.

[0028] In some possible embodiments, the electrical interconnect is a wire, the bonding layer comprises an alloy material located on the outer periphery of the wire, and / or an alloy material located between the wire and the grid line.

[0029] In some possible embodiments, a first alloy connecting layer is formed between the bonding layer and the grid line, and a second alloy connecting layer is formed between the bonding layer and the electrical interconnect.

[0030] In some possible embodiments, the bonding layer is fixed to the bottom of the electrical interconnect, and the bonding layer covers at least part of the side surface of the electrical interconnect.

[0031] In some possible embodiments, the grid line has a hole in its cross section, the length of the hole in the cross section of the grid line is less than or equal to 60% of the size of the grid line in the direction in which the length of the hole is located, and the length of the hole is the maximum size of the hole in the cross section of the grid line.

[0032] In a second aspect, the present application provides a photovoltaic system, comprising: a plurality of any of the photovoltaic modules described above.

[0033] In a third aspect, the present application provides a method for producing a photovoltaic module, comprising:

[0034] An interface layer is arranged on the grid lines on the surface of the battery piece;

[0035] The electrical interconnection is welded on the grid lines through the interface layer; during the welding process, the welding temperature is greater than the melting point of the interface layer and less than or equal to 130% of the melting point of the interface layer, and the welding time is greater than or equal to 1700 milliseconds and less than 2800 milliseconds.

[0036] In a fourth aspect of the present application, a production method of a photovoltaic module is provided, comprising:

[0037] An interface layer is arranged on the grid lines on the surface of the battery piece;

[0038] An electrical interconnection is pre-fixed on the interface layer, and the electrical interconnection is connected with the grid lines through the interface layer during the lamination process; during the lamination process, the lamination temperature is greater than 78% of the melting point of the interface layer and less than or equal to 130% of the melting point of the interface layer, and / or the lamination pressure is greater than 40 kilopascals and less than or equal to 80 kilopascals.

[0039] In some possible embodiments, the pre-fixing includes at least one of the following modes: fixing a film, fixing a tape, fixing insulating glue, and fixing conductive glue.

[0040] The photovoltaic module, the production method of the photovoltaic module, and the photovoltaic system have the same or similar beneficial effects, and thus the details are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0042] FIG. 1 shows a partial structure schematic diagram of a photovoltaic module in the related art;

[0043] FIG. 2 shows a partial structure schematic diagram of a photovoltaic module in an embodiment of the present application;

[0044] FIG. 3 shows a partial enlarged structure schematic diagram of a photovoltaic module in an embodiment of the present application;

[0045] FIG. 4 shows a partial metallographic microscope diagram of a photovoltaic module in an embodiment of the present application;

[0046] FIG. 5 shows another partial metallographic microscope diagram of a photovoltaic module in an embodiment of the present application;

[0047] Figure 6 shows a partial metallographic microscope view of one of the photovoltaic modules of the comparative examples;

[0048] Figure 7 shows a partial metallographic microscope view of another photovoltaic module of the comparative examples.

[0049] BRIEF DESCRIPTION OF DRAWINGS DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] Those skilled in the art should understand that in the disclosure of the present application, the terms "first", "second", "third", "fourth", "fifth" and the like are only used to distinguish different structures, and do not limit the number, connection relationship and the like of specific structures; in addition, the orientation or position relationship indicated by "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation on the present application.

[0052] The present application provides a photovoltaic module, which comprises a cell 1, a bonding layer 2 and an electrical interconnection 3. The type, size and the like of the cell 1 are not specifically limited, the surface of the cell 1 is provided with a grid line 11, the grid line 11 is used for conducting current outward, the surface of the cell 1 can refer to the light-receiving surface and / or the back surface, which is not specifically limited. During normal operation of the cell 1, the surface mainly receiving light is the light-receiving surface, and the back surface is opposite to the light-receiving surface. The bonding layer 2 is arranged on the grid line 11 on the surface of the cell 1, the electrical interconnection 3 is fixed on the bonding layer 2, and the electrical interconnection 3 is electrically connected with the grid line 11. The electrical interconnection 3 can be a strip-shaped metal conductive wire such as copper, silver, aluminum and nickel, can be a flat metal conductive strip, can be a conductive plate, or can be a conductive line or conductive pattern on a plate. The electrical interconnection 3 is connected in series with adjacent cells 1, thereby forming a cell string. After a plurality of cell strings are electrically connected, they serve as a power generation part of the photovoltaic module.

[0053] Referring to the related art photovoltaic module shown in FIG. 1, the applicant finds that the tensile force of the related art photovoltaic module is unqualified, which leads to that the connection between the grid line 11 and the electrical interconnection 3 through the bonding layer 2 is not firm enough, and the electrical interconnection layer is offset and short-circuited after the offset, or the electrical interconnection falls off during the reliability test of the photovoltaic module, and so on. The applicant analyzes and studies the phenomenon and finds that there are many factors causing the electrical interconnection to fall off, such as the volume and mass of the bonding layer, the density and hole of the bonding layer, the contact area between the electrical interconnection and the bonding layer, and so on, and each factor contributes differently to the falling off of the electrical interconnection.

[0054] In view of the above technical problems, referring to FIG. 2, the present application improves the photovoltaic module, especially the bonding layer connecting the electrical interconnection and the grid line in the photovoltaic module. Specifically, in the cross section of the bonding layer 2 of the photovoltaic module, the length of the hole 21 is less than or equal to 60% of the size of the bonding layer in the direction of the length of the hole, and the length of the hole 21 is the maximum size of the hole in the cross section of the bonding layer. At this time, although there is a hole in the bonding layer for connecting the grid line and the electrical interconnection, the size of the hole is small, which can ensure the bonding force of the grid line, the bonding layer and the electrical interconnection at the position of the electrical interconnection of the bonding layer in the photovoltaic module, and the bonding force (peeling strength) is maintained at more than 1.0 N / mm during the long-term light irradiation, water vapor erosion, wind-induced vibration and other conditions during the service of the photovoltaic module. In addition, the small size of the hole is conducive to the diffusion of the metal elements of the grid line in the bonding layer, and is conducive to the formation of a stable connection between the bonding layer and the grid line. Furthermore, the small size of the hole in the bonding layer can reduce the retention of water vapor in the bonding layer, thereby improving the durability of the bonding layer. At the same time, the process cost and process difficulty can also be taken into account.

[0055] When there is a hole in the cross section of the bonding layer, the size from top to bottom of the hole is the maximum, and the direction from top to bottom is the length direction of the hole. For example, in the cross section of the bonding layer 2 of the photovoltaic module, the length of the hole 21 can be 60%, 55%, 50%, 45%, 40%, 35%, 30%, 28%, 25%, 10%, 20%, 15%, 5%, 1% and so on of the size of the bonding layer in the direction of the length of the hole.

[0056] It should be noted that in the case that the number of holes in the same cross section of the bonding layer is greater than or equal to 2, for each hole in the cross section, the length of the hole is less than or equal to 60% of the size of the bonding layer in the direction of the length of the hole. For example, in the same cross section of the bonding layer, there are hole A and hole B, the length of hole A is less than or equal to 60% of the size of the bonding layer in the direction of the length of hole A, and the length of hole A is the maximum size of hole A in the cross section of the bonding layer. At the same time, the length of hole B is less than or equal to 60% of the size of the bonding layer in the direction of the length of hole B, and the length of hole B is the maximum size of hole B in the cross section of the bonding layer. It should be noted that in the case that there are multiple holes in the same cross section of the bonding layer, whether the directions of the lengths of different holes are parallel or not is not specifically limited, and can be parallel or intersecting. For example, for the foregoing example, the direction of the length of hole A is parallel to the direction of the length of hole B, or the direction of the length of hole A intersects the direction of the length of hole B.

[0057] In some possible embodiments, the length of the hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the length of the hole, that is, the length of each hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the length of the corresponding hole, and further, the size of hole 21 is reduced in the cross section of the bonding layer, and the structure of the small hole in the bonding layer is relatively stable relative to the entire bonding layer, and the probability of collapse or tearing of the hole under pressure or tension is greatly reduced, so that the grid lines and electrical connections connected by the bonding layer are more stable.

[0058] For example, the length of hole 21 in the cross section of the bonding layer 2 of the photovoltaic module can be 33%, 30%, 28%, 25%, 10%, 20%, 15%, 5%, 1%, etc. of the size of the bonding layer in the direction of the length of the hole.

[0059] In some embodiments, the width of the hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the width of the hole, that is, the width of each hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the width of the corresponding hole. It should be noted that for the same hole in the same cross section, the direction of the width is perpendicular to the direction of the length. For the same hole in the same cross section, the width is less than or equal to the length. When the width of the hole is less than or equal to 33% of the size of the bonding layer in the direction of the width of the hole, the length of the hole is also necessarily small, and at this time, the size of each position of the entire hole can be well controlled, and the structural stability of the bonding layer is more optimal.

[0060] For example, in the cross section of the junction layer 2 of the photovoltaic module, the width of the hole 21 can be 33%, 30%, 25%, 33%, 20%, 15%, 10%, 12.5%, 7%, 5% of the size of the junction layer in the direction of the width of the hole.

[0061] It should be noted that in the case where the number of holes in the same cross section of the junction layer is greater than or equal to 2, for each hole in the cross section, the width of the hole is less than or equal to 33% of the size of the junction layer in the direction of the width of the hole. For example, in the same cross section of the junction layer, there are hole A and hole B, the width of hole A is less than or equal to 33% of the size of the junction layer in the direction of the width of hole A, the direction of the width of hole A is perpendicular to the direction of the length of hole A, and the length of hole A is the maximum size of hole A in the cross section of the junction layer. At the same time, the width of hole B is less than or equal to 33% of the size of the junction layer in the direction of the width of hole B, the direction of the width of hole B is perpendicular to the direction of the length of hole B, and the length of hole B is the maximum size of hole B in the cross section of the junction layer. It should be noted that in the case where there are multiple holes in the same cross section of the junction layer, whether the directions of the widths of different holes are parallel or not is not specifically limited. For example, for the foregoing example, the direction of the width of hole A is parallel to the direction of the width of hole B, or the direction of the width of hole A intersects the direction of the width of hole B.

[0062] In some possible embodiments, in the cross section of the junction layer, the width of the hole is less than or equal to 80% of the length of the hole, the direction of the width of the hole in the cross section of the junction layer is perpendicular to the direction of the length of the hole, and on the basis that the length of the hole is less than or equal to 60% of the size of the junction layer in the direction of the length of the hole in the cross section of the junction layer, the length of the hole is controlled, and the width of the hole is controlled, and the width of the hole is less than the length. The length and width of the hole can be further controlled within a suitable range. It should be noted that for the same hole in the same cross section, the direction of the width is perpendicular to the direction of the length.

[0063] For example, in the cross section of the junction layer 2 of the photovoltaic module, the width of the hole 21 can be 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 3%, 1%, 0.5% of the length of the hole.

[0064] It should be noted that for the same hole 21 of the same section, whether the proportion of the length of the hole 21 to the size of the joint layer 2 in the direction in which the length of the hole 21 is located is equal to the proportion of the width of the hole 21 to the size of the joint layer 2 in the direction in which the width of the hole 21 is located is not specifically limited. For example, for the same hole 21 of the same section, the proportion of the length of the hole 21 to the size of the joint layer 2 in the direction in which the length of the hole 21 is located can be equal to the proportion of the width of the hole 21 to the size of the joint layer 2 in the direction in which the width of the hole 21 is located, or either of the two is greater than the other.

[0065] In some possible embodiments, the cross-sectional area of the hole in the cross section of the joint layer is less than or equal to 33% of the cross-sectional area of the joint layer, that is, the cross-sectional area of each hole 21 in the cross section of the joint layer is less than or equal to 33% of the area of the cross section of the joint layer, and the cross-sectional area of the hole 21 refers to the area of the hole 21 in the cross section of the joint layer. Controlling the cross-sectional area of the hole can ensure that the controlled overall area is relatively small relative to the joint layer, and at the same time, controlling the maximum size of the hole, that is, the length, can ensure that the hole in the joint layer is not only small in overall area but also small in maximum size, that is, in the case of a small overall hole, an excessively long shape does not occur, avoiding the problem of joint layer splitting and tearing caused by a long hole.

[0066] For example, the cross-sectional area of the hole in the cross section of the joint layer can be 33%, 30%, 25%, 20%, 18%, 15%, 12%, 10%, 8%, 5%, 3%, etc. of the area of the cross section of the joint layer.

[0067] In some possible embodiments, the cross-sectional area of the hole in the cross section of the joint layer is less than or equal to 2500 μm 2 , that is, the cross-sectional area of each hole 21 in the cross section of the joint layer is less than or equal to 2500 μm 2 , and the cross-sectional area of the hole 21 refers to the area of the hole 21 in the cross section of the joint layer. More specifically, when the hole 21 with a cross-sectional area of less than or equal to 2500 μm 2 exists in the cross section of the joint layer, the tensile strength or peel strength of the joint layer 2 and the electrical interconnection 3 is large, the connection between the joint layer 2 and the electrical interconnection 3 is firm and reliable, can meet the product quality requirements of the photovoltaic module, and has been verified to still maintain the reliable connection between the electrical interconnection and the grid line under the conditions of long-term sunlight, water vapor erosion, and wind vibration.

[0068] For example, the cross-sectional area of the hole in the cross section of the joint layer can be 2500 μm 2 , 220 μm 2 , 800 μm 2 , 1800 μm 2, 260 μm 2 , 1500 μm 2 , 113 μm 2 , 122 μm 2 , 1000 μm 2 , 900 μm 2 , 88 μm 2 , 53 μm 2 , 32 μm 2 , 25 μm 2 , 11 μm 2 , 5.2 μm 2 , 3.7 μm 2 , 1 μm 2 , 0.35 μm 2 .

[0069] Further, the cross-sectional area of the hole in the cross-section of the bonding layer is less than or equal to 250 μm 2 At this time, since the area of the hole is relatively small, the influence on the bonding layer is very small, and the photovoltaic module can maintain good electrical conduction performance during the entire service period.

[0070] For example, the cross-sectional area of each hole in the cross-section of the bonding layer can be 250 μm 2 , 220 μm 2 , 200 μm 2 , 180 μm 2 , 160 μm 2 , 150 μm 2 , 130 μm 2 , 120 μm 2 , 100 μm 2 , 90 μm 2 , 80 μm 2 , 50 μm 2 , 30 μm 2 , 20 μm 2 , 10 μm 2 , 5 μm 2 , 3 μm 2 , 1 μm 2 , 0.5 μm 2 .

[0071] In some possible embodiments, the aforementioned joint layer has a cross section, a longitudinal section, or an oblique section. The cross section refers to a section obtained by cutting the joint layer in a direction perpendicular to the length of the electrical interconnection. The number of cross sections can be multiple. The longitudinal section refers to a section obtained by cutting the joint layer in a direction along the length of the electrical interconnection. The number of longitudinal sections can be multiple. The oblique section refers to a section obtained by cutting the joint layer in a direction intersecting the cutting line of the cross section or the longitudinal section. The number of oblique sections is usually multiple. The length of the hole in each section of the joint layer meets the aforementioned size limitation, and thus the length of the hole in the section obtained by cutting the joint layer in different directions is controlled within a suitable range, which can ensure the structural stability of the joint layer in the corresponding section. When the structural stability of each section of the joint layer is good, the reliability of the joint layer under tension or pressure is high, thereby ensuring the stability of the electrical connection of the joint layer in the position of the photovoltaic module during service.

[0072] In some embodiments, the shape of the hole 21 in the section of the joint layer 2 is regular or irregular, and the shape of the hole 21 is various. For example, whether the length and width of one hole 21 are equal is not limited. In some embodiments, the number of holes 21 in the section of the joint layer 2 is less than or equal to 10, that is, the number of holes 21 in the same section of the joint layer 2 is less than or equal to 10. On the basis of the small size of each hole 21, the number of holes 21 in the same section is further limited to be small, and thus the number of holes 21 in the joint layer 2 in the joint layer is also small, thereby further improving the reliability of the joint layer. For example, the number of holes 21 in the same section of the joint layer 2 can be 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1.

[0073] For example, the length of each hole in the same section of the joint layer 2 is less than or equal to 60% of the length of the joint layer 2 in the direction of the length of the hole. The number of holes 21 in the same section of the joint layer 2 can be 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1.

[0074] Further, the number of holes 21 in the same section of the joint layer 2 is less than or equal to 5. On the basis of the small size of each hole 21, the number of holes 21 in the same section of the joint layer 2 is further small, and thus the tensile strength or peel strength of the joint layer 2 and the electrical interconnection 3 is further improved, thereby ensuring the quality of the photovoltaic module.

[0075] For example, the length of each hole in the same section of the joint layer 2 is less than or equal to 60% of the length of the joint layer 2 in the direction of the length of the hole. The number of holes 21 in the same section of the joint layer 2 can be 5, 4, 3, 2, or 1.

[0076] In some possible embodiments, the bonding layer 2 has a spacing between adjacent holes in the same cross section, or in other words, the adjacent holes are not connected to each other or through the bonding layer, or in other words, the holes in the bonding layer are not aggregated, and the size of the holes is small, so that the bonding layer 2 has a large pulling force with the electrical interconnection 3, thereby ensuring the quality of the photovoltaic module.

[0077] In some possible embodiments, the bonding layer 2 includes a lower surface close to the grid line 11, an upper surface close to the electrical interconnection 3, and an internal region in the surface of the bonding layer 2, and in the cross section of the bonding layer, the cross-sectional area of the largest hole in the upper surface of the bonding layer is smaller than the cross-sectional area of the largest hole in the internal region of the bonding layer, and in particular, the cross-sectional area of the largest hole in the upper surface of the bonding layer is smaller than the cross-sectional area of the largest hole in the internal region of the bonding layer. The cross-sectional area of the largest hole in the lower surface of the bonding layer is smaller than the cross-sectional area of the largest hole in the internal region of the bonding layer.

[0078] In the surface of the bonding layer 2, the lower surface close to the grid line and the upper surface close to the electrical interconnection 3 are both interfaces that need to be connected, and the internal region of the bonding layer is the part between the upper surface and the lower surface of the bonding layer, which is usually not an interface that needs to be connected, that is, the cross-sectional area of the hole at the interface to be connected is small, so that the connection is more real, and the bonding layer 2 has a large pulling force with the electrical interconnection 3, thereby ensuring the reliability of the electrical connection.

[0079] It should be noted that in the case where the bonding layer 2 is provided with a solder pad between the grid line 11 and the bonding layer 2, the lower surface here is the surface of the bonding layer 2 close to the solder pad.

[0080] In some possible embodiments, the bonding layer is fixed and electrically connected to the grid line through a connecting portion provided on the cell, and the connecting portion is between the bonding layer and the grid line, and the width of the connecting portion is greater than or equal to the width of the grid line, and the width of the bonding layer is greater than the width of the grid line. By providing the connecting portion, the connection area of the bonding layer and the grid line can be increased, the connection strength can be improved, and the connection reliability of the bonding layer and the grid line is further improved. Here, the connecting portion can be a solder pad. Here, the width of the grid line is perpendicular to the extension direction of the grid line, and in the photovoltaic module, the direction in which the width of the connecting portion is located, the direction in which the width of the grid line is located, and the direction in which the width of the bonding layer is located are parallel to each other.

[0081] It should be understood that the peeling strength between the electrical interconnection 3 and the bonding layer 2 refers to the minimum force required for unit width peeling from the contact surface of the electrical interconnection 3 and the bonding layer 2, which can be obtained by a force meter, a mechanical sensor, etc. Compared with the related art, the peeling strength between the electrical interconnection 3 and the bonding layer 2 is greater, the connection between the grid lines, the bonding layer and the electrical interconnection is more firm and reliable, and thus the quality of the photovoltaic module is further improved. In some embodiments, the electrical interconnection is fixed with the cell piece through a welding process and / or a laminating bonding process. Here, welding refers to the welding and bonding of the electrical interconnection and the grid lines of the cell piece together by infrared, laser, etc. Here, laminating bonding refers to the bonding of the electrical interconnection and the grid lines of the cell piece together by means of the temperature in the laminating process. The connection mode of the electrical interconnection and the cell piece is flexible and diverse.

[0082] In some embodiments, a fixing layer is provided on the electrical interconnection, specifically, a fixing layer is provided on the side of the electrical interconnection away from the cell piece. The fixing layer fixes the electrical interconnection and the cell piece. By providing the fixing layer, the relative position of the electrical interconnection or the cell piece can be prevented from being displaced greatly before firm connection. The fixing layer includes one or more combinations of a fixing film, a fixing tape, insulating glue and conductive glue.

[0083] In some embodiments, the battery piece is a back contact battery piece, and the light-receiving surface of the back contact battery piece is not blocked by the grid lines, thereby making the conversion efficiency of the photovoltaic module higher. In this case, the back surface of the battery piece is provided with grid lines, and at least one side of the bonding layer is provided with an insulating block for isolating the fine grid lines. Specifically, the insulating block is arranged at a part of the position of the electrical interconnection close to the battery piece, and the bonding layer is arranged at another part of the position of the electrical interconnection close to the battery piece. The top of the bonding layer refers to the highest position of the end of the bonding layer away from the battery piece, and the top of the insulating block refers to the highest position of the end of the insulating block away from the battery piece. The top of the bonding layer and the top of the insulating block are both adjacent to the electrical interconnection, and the height difference between the top of the bonding layer and the top of the insulating block is less than 15 μm. That is, the top of the bonding layer and the top of the insulating block are as level as possible. In this way, the top of the insulating block is not too high, and the top of the insulating block will not apply a force away from the battery piece to the electrical interconnection to lift the electrical interconnection, so that the connection between the grid lines, the bonding layer and the electrical interconnection is more firm and reliable, and the quality of the photovoltaic module is further improved. In addition, during the service of the photovoltaic module for 10 years or even longer, if the electrical interconnection electrically connected with the battery piece is subjected to the lifting force of the insulating block for a long time, the electrical connection of the photovoltaic module is prone to failure. For example, the height difference between the top of the bonding layer and the top of the insulating block can be 15 μm, 14 μm, 13 μm, 12 μm, 11 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, etc. The battery piece in the present application can also be a bifacial battery piece, etc., which is not limited in particular.

[0084] In some embodiments, the number of electrical interconnections in the photovoltaic module is multiple, and the head of at least one electrical interconnection extends out of the bonding layer, or the head of at least one electrical interconnection is located in the 2 / 3 region of the bonding layer away from the tail of the electrical interconnection. The electrical interconnection and the bonding layer will undergo movement, transportation, lamination and other operations during the connection process or after the connection. The head of the electrical interconnection is prone to warping and separated from the battery piece and the bonding layer. When the head of the electrical interconnection extends out of the bonding layer, even if the head of the electrical interconnection warps, the tail of the electrical interconnection can still be stably connected, which can improve the adverse effects of the warping of the head of the electrical interconnection and ensure the reliability of the connection of the bonding layer at the position of the head of the electrical interconnection. The head of the electrical interconnection is located in the 2 / 3 region of the bonding layer away from the tail of the electrical interconnection, or in other words, the head of the electrical interconnection cannot be located in the 1 / 3 region of the bonding layer close to the tail of the electrical interconnection. Specifically, the bonding layer is divided into three parts along the length direction of the electrical interconnection. Preferably, the head of the electrical interconnection is arranged in the 2 / 3 region of the bonding layer away from the tail of the electrical interconnection, rather than in the 1 / 3 region of the bonding layer close to the tail of the electrical interconnection. In this way, the bonding region of the electrical interconnection and the bonding layer is longer, and the connection of the electrical interconnection and the bonding layer is more firm.

[0085] In some embodiments, the electrical interconnect is a wire, and the bonding layer includes alloy material on the outer periphery of the wire and / or alloy material between the wire and the grid line. That is, the alloy material can be alloy material only on the outer periphery of the wire, such as tin alloy material on the outer periphery of a copper wire; or the alloy material can be alloy material that is first disposed on the surface of the grid line by screen printing or spot coating and the like, and then solidified by baking, and then electrically connected together with the electrical interconnect; for example, tin alloy material that is screen printed on the electrode; or the alloy material includes not only alloy material on the outer periphery of the wire, but also alloy material that is first disposed on the surface of the grid line by screen printing or spot coating and the like, and then solidified by baking, and then electrically connected together with the alloy material on the outer periphery of the aforementioned electrical interconnect. Taking a solder strip as an example, the bonding layer of the present application can refer to the tin alloy material disposed between the copper core of the solder strip and the grid line, which can be specifically the tin alloy material that is wrapped on the outer periphery of the copper core of the solder strip and is molten after electrical connection. Or the tin alloy material can be tin alloy that is disposed on the surface of the grid line of the battery by printing, coating and the like, or the tin alloy material can also be a combination of tin alloy disposed on the surface of the grid line of the battery by printing, coating and the like and tin alloy disposed on the surface of the solder strip.

[0086] When the bonding layer includes a combination of tin alloy printed or spot coated on the surface of the battery and tin alloy on the surface of the electrical interconnect, the two are mainly consistent in cost and fused together. The tin alloy here can refer to tin-lead alloy, tin-lead-bismuth alloy and the like, and the specific composition is not limited.

[0087] In some embodiments, a first alloy connection layer is formed between the bonding layer and the grid line, and a second alloy connection layer is formed between the bonding layer and the electrical interconnect, that is, a firm alloy connection layer is formed between the bonding layer and the grid line, and a firm alloy connection layer is also formed between the bonding layer and the electrical interconnect, so that the connection between the grid line, the bonding layer and the electrical interconnect is more reliable. The material composition of the first alloy connection layer and the second alloy connection layer is not specifically limited.

[0088] Referring to FIG. 3, in some embodiments, the bonding layer 2 is fixed to the bottom of the electrical interconnect 3, and covers at least part of the side surface of the electrical interconnect 3. At this time, the bonding layer covers the bottom surface and the side surface of the electrical interconnect (such as a solder strip), so that the bonding layer and the electrical interconnect can be stably connected, and the shaking of the electrical connection on the surface of the bonding layer can be avoided. For example, when the electrical interconnect is a rectangular cross-section solder strip, the bonding layer can cover part of the side surface of the solder strip, or can cover the entire side surface. When the electrical interconnect is a circular cross-section solder strip, the bonding layer can cover part of the side surface of the solder strip.

[0089] In some embodiments, the gate line has a hole in the cross section of the gate line, and the length of the hole in the cross section of the gate line is less than or equal to 60% of the size of the gate line in the direction of the length of the hole, and the length of the hole is the maximum size of the hole in the cross section of the gate line. The gate line is mainly composed of a metal material. By controlling the size of the hole in the gate line while controlling the joint layer hole, the reliability of the gate line on the surface of the battery piece can be ensured.

[0090] For example, the gate line has a hole in the cross section of the gate line, and the length of the hole in the cross section of the gate line can be 60%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 8%, 5%, 3%, etc. of the size of the gate line in the direction of the length of the hole.

[0091] The application also provides a photovoltaic system comprising a plurality of photovoltaic assemblies. The photovoltaic system can further comprise a photovoltaic support and the like. The other structures of the photovoltaic system are not limited. Compared with the photovoltaic assembly, the photovoltaic system can further expand the application scenarios of the battery piece.

[0092] The photovoltaic system has the same or similar beneficial effects as any of the aforementioned photovoltaic assemblies. The relevant parts can be referred to each other. To avoid repetition, this will not be repeated here.

[0093] The application also provides a preparation method of a photovoltaic assembly, comprising the following steps.

[0094] Step 101, disposing a joint layer on the gate line on the surface of the battery piece.

[0095] The tin paste and the like can be printed on the gate line on the surface of the battery piece by printing and the like, and then the joint layer is obtained by drying and curing. The specific setting method of the joint layer is not limited.

[0096] Step 102, welding the electrical interconnection on the gate line through the joint layer; wherein, during the welding process, the welding temperature is greater than the melting point of the joint layer, less than or equal to 130% of the melting point of the joint layer, and the welding time is greater than or equal to 1700 milliseconds, less than 2800 milliseconds.

[0097] Alternatively, the step 102 can be replaced by the following step 103, and the step 102 and the step 103 can be executed alternatively.

[0098] Step 103, pre-fixing the electrical interconnection on the joint layer, and connecting the electrical interconnection with the gate line through the joint layer during the lamination process; during the lamination process, the lamination temperature is greater than 78% of the melting point of the joint layer, less than or equal to 130% of the melting point of the joint layer, and / or the lamination pressure is greater than 40 kilopascals, less than or equal to 80 kilopascals.

[0099] In the present application, the difference between step 102 and step 103 is mainly the fixation of the electrical interconnection and the bonding layer in the photovoltaic module, and step 102 and step 103 are two fixation modes of the electrical interconnection and the bonding layer. Step 102 is to weld the electrical interconnection on the bonding layer by infrared, laser and other methods to realize the connection of the grid line, the bonding layer and the electrical interconnection, and then to laminate. Step 103 is to pre-fix the electrical interconnection on the bonding layer, and then to connect the bonding layer and the electrical interconnection by means of the laminating environment during the laminating process. The pre-fixing is mainly to keep the relative position of the bonding layer and the electrical interconnection unchanged before and during the laminating process, and the firm and reliable connection of the bonding layer and the electrical interconnection has not been realized.

[0100] For the mode of welding the electrical interconnection on the bonding layer, compared with the welding temperature being the melting point of the bonding layer and the long welding time in the related art, in the present application, the welding temperature is appropriately increased and the welding time is appropriately reduced, which can greatly reduce the size and quantity of the holes in the bonding layer of the formed photovoltaic module, so that the connection of the grid line, the bonding layer and the electrical interconnection in the photovoltaic module is firm and reliable. More specifically, for the mode of welding the electrical interconnection on the bonding layer, in the present application, the welding temperature is greater than the melting point of the bonding layer and less than or equal to 130% of the melting point of the bonding layer, and the welding time is greater than or equal to 1700 milliseconds and less than 2800 milliseconds. Further, in the present application, the welding temperature is greater than the melting point of the bonding layer and less than or equal to 120% of the melting point of the bonding layer, and the welding time is greater than or equal to 1900 milliseconds and less than 2500 milliseconds.

[0101] For example, for the mode of welding the electrical interconnection on the bonding layer and then laminating, in the present application, the welding temperature can be 101%, 102%, 105%, 109%, 110%, 110.7%, 115%, 116%, 118%, 119%, 120%, 121%, 125%, 127.9%, 130% of the melting point of the bonding layer, and the welding time can be 1700 milliseconds, 1800 milliseconds, 1900 milliseconds, 1910 milliseconds, 1950 milliseconds, 1990 milliseconds, 2000 milliseconds, 2100 milliseconds, 2150 milliseconds, 2200 milliseconds, 2250 milliseconds, 2300 milliseconds, 2350 milliseconds, 2400 milliseconds, 2450 milliseconds, 2050 milliseconds, 2400 milliseconds, 2499 milliseconds, 2500 milliseconds, 2600 milliseconds, 2700 milliseconds, 2799 milliseconds.

[0102] For example, for the mode of welding the electrical interconnection on the bonding layer and then laminating, in the present application, the welding temperature can be 101%, 102%, 105%, 109%, 110%, 110.7%, 115%, 116%, 118%, 119%, 120%, 121%, 125%, 127.9%, 130% of the melting point of the bonding layer, and the welding time can be 1700 milliseconds, 1800 milliseconds, 1900 milliseconds, 1910 milliseconds, 1950 milliseconds, 1990 milliseconds, 2000 milliseconds, 2100 milliseconds, 2150 milliseconds, 2200 milliseconds, 2250 milliseconds, 2300 milliseconds, 2350 milliseconds, 2400 milliseconds, 2450 milliseconds, 2050 milliseconds, 2400 milliseconds, 2499 milliseconds, 2500 milliseconds, 2600 milliseconds, 2700 milliseconds, 2799 milliseconds.

[0103] It should be noted that for the way of welding the electrical interconnection on the bonding layer and then laminating, the process parameters of lamination can be consistent with the process parameters of lamination of the related art, and no specific limitation is made.

[0104] For the way of pre-fixing the electrical interconnection on the bonding layer to realize the connection of the electrical interconnection and the bonding layer in the lamination process, there are mainly three ways to reduce the size and number of holes in the bonding layer in the present application. One way is that the lamination temperature is greater than 78% of the melting point of the bonding layer and less than or equal to 130% of the melting point of the bonding layer during the lamination process. Further, the lamination temperature is greater than 82.2% of the melting point of the bonding layer and less than or equal to 120% of the melting point of the bonding layer during the lamination process.

[0105] Another way is that the lamination pressure is greater than 40 kilopascals and less than or equal to 80 kilopascals during the lamination process. Further, the lamination pressure is greater than 50 kilopascals and less than or equal to 70 kilopascals during the lamination process.

[0106] The third way is that the lamination temperature is greater than 78% of the melting point of the bonding layer and less than or equal to 130% of the melting point of the bonding layer during the lamination process, and the lamination pressure is greater than 40 kilopascals and less than or equal to 80 kilopascals during the lamination process. Further, the lamination temperature is greater than 82.2% of the melting point of the bonding layer and less than or equal to 120% of the melting point of the bonding layer during the lamination process, and the lamination pressure is greater than 50 kilopascals and less than or equal to 70 kilopascals during the lamination process. Relative to the lamination process parameters of the related art, the present application mainly reduces the size and number of holes in the bonding layer by increasing the lamination temperature and / or increasing the lamination pressure, and improves the connection reliability of the bonding layer and the electrical interconnection.

[0107] For example, for the way of pre-fixing the electrical interconnection on the bonding layer to realize the connection of the electrical interconnection and the bonding layer in the lamination process, the lamination temperature in the present application can be 78%, 80%, 82.5%, 85%, 89%, 90%, 92%, 95%, 97%, 100%, 102%, 105%, 109%, 110%, 110.7%, 115%, 116%, 118%, 119%, 120%, 125%, 130% of the melting point of the bonding layer, and / or the lamination pressure can be 40.01 kilopascals, 45 kilopascals, 50.02 kilopascals, 50.5 kilopascals, 53 kilopascals, 55 kilopascals, 58 kilopascals, 60 kilopascals, 62 kilopascals, 65 kilopascals, 66 kilopascals, 68 kilopascals, 69 kilopascals, 70 kilopascals, 75 kilopascals, 80 kilopascals.

[0108] For another example, the melting point of the bonding layer is 180℃, and for the way of realizing the connection between the electrical interconnection and the bonding layer in the lamination process by pre-fixing the electrical interconnection on the bonding layer, in this application, the lamination temperature can be greater than 148℃ and less than or equal to 210℃, and the lamination pressure can be 52kPa to 70kPa.

[0109] For another example, the melting point of the bonding layer is 140℃, and for the way of realizing the connection between the electrical interconnection and the bonding layer in the lamination process by pre-fixing the electrical interconnection on the bonding layer, in this application, the lamination temperature can be 150℃, and the lamination pressure can be 52kPa to 70kPa.

[0110] In some possible embodiments, for the way of realizing the connection between the electrical interconnection and the bonding layer in the lamination process by pre-fixing the electrical interconnection on the bonding layer, in this application, the pre-fixing can include at least one of the following ways: fixing film, fixing tape, insulating glue, and conductive glue, which are easy to realize mass production of pre-fixing. The fixing film, the fixing tape, the insulating glue, and the conductive glue herein can refer to the related descriptions in the foregoing, and can achieve the same or similar beneficial effects. To avoid repetition, they will not be described here again.

[0111] The production method of the photovoltaic module can prepare any of the aforementioned photovoltaic modules, and the related parts between the two can be referred to each other. To avoid repetition, they will not be described here again.

[0112] The application will be further explained in conjunction with specific examples.

[0113] Example 1

[0114] The cell piece is a back contact cell piece, and the back light surface of the cell piece is provided with a grid line. 200 cell pieces of the same batch are interconnected. Specifically, the melting point of the bonding layer is 180℃, the electrical interconnection is welded on the bonding layer by infrared method, and then the photovoltaic module is prepared by lamination. The welding temperature is 205℃, the welding time is 2200 milliseconds, and in the lamination process, the lamination temperature is 148℃ and the lamination pressure is 50kPa. The local metallographic microscope graph of the obtained photovoltaic module is shown in Figure 4, and in Figure 4, from top to bottom, the electrical interconnection, the bonding layer and the electrode paste are sequentially arranged. From Figure 4, it can be seen that by appropriately increasing the welding temperature and appropriately reducing the welding time, the size of the hole in the bonding layer of the photovoltaic module is smaller, and the number is also less. The size and number of holes in the bonding layer on each cell piece in the photovoltaic module are tested, and the average values are shown in Table 1 below. The average value of the peel strength between the bonding layer and the electrical interconnection on each cell piece in the photovoltaic module is also shown in Table 1 below.

[0115] Example 2

[0116] The difference between Example 2 and Example 1 is only that the electrical interconnector is pre-fixed on the bonding layer, and the electrical interconnector is connected with the grid line through the bonding layer during the lamination process. In Example 2, the pre-fixing mode is selected as the conductive adhesive. During the lamination process, the lamination temperature is 175°C, and the lamination pressure is 62 kPa. The partial metallographic microscope image of the photovoltaic module obtained in Example 2 is shown in FIG. 5, and FIG. 5 shows from top to bottom: the electrical interconnector, the bonding layer and the electrode paste. It can be seen from FIG. 5 that, in the present application, by appropriately increasing the lamination temperature and / or appropriately increasing the lamination pressure, the size of the holes in the bonding layer of the photovoltaic module is smaller, and the number is also smaller. The average value of the size and number of the holes in the bonding layer on each cell in the photovoltaic module is shown in Table 2 below. The average value of the peeling strength of the bonding layer and the electrical interconnector on each cell in the photovoltaic module is also shown in Table 2 below.

[0117] Comparative Example 1

[0118] The difference between Comparative Example 1 and Example 1 is only that the welding temperature is 180°C, and the welding time is 2800 ms. The partial metallographic microscope image of the photovoltaic module obtained in Comparative Example 1 is shown in FIG. 6, and FIG. 6 shows from top to bottom: the electrical interconnector, the bonding layer and the electrode paste. It can be seen from FIG. 6 that the size of the holes in the bonding layer of the photovoltaic module is larger, and the number is also larger. The average value of the size and number of the holes in the bonding layer on each cell in the photovoltaic module is shown in Table 1 below. The average value of the peeling strength of the bonding layer and the electrical interconnector on each cell in the photovoltaic module is also shown in Table 1 below.

[0119] Comparative Example 2

[0120] The difference between Comparative Example 2 and Example 2 is only that, in Comparative Example 2, during the lamination process, the lamination temperature is 140°C, and the lamination pressure is 38 kPa. The partial metallographic microscope image of the photovoltaic module obtained in Comparative Example 2 is shown in FIG. 7, and FIG. 7 shows from top to bottom: the electrical interconnector, the bonding layer and the electrode paste. It can be seen from FIG. 7 that the size of the holes in the bonding layer of the photovoltaic module is larger, and the number is also larger. The average value of the size and number of the holes in the bonding layer on each cell in the photovoltaic module is shown in Table 2 below. The average value of the peeling strength of the bonding layer and the electrical interconnector on each cell in the photovoltaic module is also shown in Table 2 below.

[0121] Table 1: Parameter comparison table of Example 1 and Comparative Example 1

[0122] Table 2: Parameter comparison table of Example 2 and Comparative Example 2

[0123] From FIG. 4 to FIG. 7, it can be concluded that, in the present application, the size and quantity of the holes in the bonding layer are obviously reduced by adjusting the process parameters in the welding process or the laminating process, thereby ensuring the tensile force of the bonding layer and the electrical interconnection in the photovoltaic module and ensuring the quality of the photovoltaic module. From Table 1, it can be concluded that, in the present application, by appropriately increasing the welding temperature and appropriately reducing the welding time in the welding process, the peel strength of the bonding layer and the electrical interconnection in the photovoltaic module is increased from 0.42 N / mm to 1.28 N / mm, and the peel strength is increased by 0.86 N / mm. From Table 2, it can be concluded that, in the present application, by appropriately increasing the laminating temperature and / or appropriately increasing the laminating pressure in the laminating process, the peel strength of the bonding layer and the electrical interconnection in the photovoltaic module is increased from 0.35 N / mm to 1.36 N / mm, and the peel strength is increased by 1.01 N / mm. The present application obviously reduces the size and quantity of the holes in the bonding layer, thereby ensuring the tensile force of the bonding layer and the electrical interconnection in the photovoltaic module and ensuring the quality of the photovoltaic module.

[0124] It should be noted that, for the method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the embodiments of the present application are not limited by the action sequence described, because according to the embodiments of the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification all belong to preferred embodiments, and the actions involved are not necessarily essential for the embodiments of the present application.

Claims

1. A photovoltaic module, wherein, The battery piece comprises: a battery piece; a surface of the battery piece is provided with a grid line; a bonding layer is provided on the grid line; the length of the hole in the cross section of the bonding layer is less than or equal to 60% of the size of the bonding layer in the direction of the length of the hole, the length of the hole being the maximum size of the hole in the cross section of the bonding layer; an electrical interconnection is fixed on the bonding layer, and the electrical interconnection is electrically connected with the grid line.

2. The photovoltaic module of claim 1, wherein, The length of the hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the length of the hole.

3. The photovoltaic module of claim 1, wherein, The width of the hole in the cross section of the bonding layer is less than or equal to 33% of the size of the bonding layer in the direction of the width of the hole, and the width direction of the hole in the cross section of the bonding layer is perpendicular to the length direction of the hole.

4. The photovoltaic module of claim 1, wherein, The width direction of the hole in the cross section of the bonding layer is perpendicular to the length direction of the hole; the width of the hole in the cross section of the bonding layer is less than or equal to 80% of the length of the hole.

5. The photovoltaic module of claim 1, wherein, The cross-sectional area of the hole in the cross section of the bonding layer is less than or equal to 33% of the cross-sectional area of the bonding layer.

6. The photovoltaic module of claim 5, wherein, The cross-sectional area of the hole in the cross-section of the joining layer is less than or equal to 2500 μm 2 .

7. The photovoltaic module of claim 1, wherein, The cross section of the bonding layer is a transverse cross section, a longitudinal cross section, or an oblique cross section.

8. The photovoltaic module of claim 1, wherein, The number of holes in the cross section of the bonding layer is less than or equal to 10.

9. The photovoltaic module of claim 1, wherein, The shape of the hole in the cross section of the bonding layer is regular or irregular.

10. The photovoltaic module of any of claims 1-9, wherein, The cross-sectional area of the largest hole on the upper surface and the lower surface of the bonding layer is less than the cross-sectional area of the largest hole inside the bonding layer.

11. The photovoltaic module of any of claims 1-9, wherein, The battery piece is provided with a connecting part, the bonding layer is fixed and electrically connected with the grid line through the connecting part; on the battery piece, the width of the connecting part is greater than or equal to the width of the grid line; the width of the bonding layer is greater than the width of the grid line.

12. The photovoltaic module of any of claims 1-9, wherein, The electrical interconnection is fixed on the battery piece through a welding process and / or a laminated bonding process.

13. The photovoltaic module of any of claims 1-9, wherein, The electrical interconnection is provided with a fixing layer; The fixing layer comprises one or more combinations of a fixing film, a fixing tape, an insulating glue, and a conductive glue.

14. The photovoltaic module of any of claims 1-9, wherein, The battery piece is a back contact battery piece, at least one side of the bonding layer is provided with an insulating block along the extension direction of the electrical interconnection, and the height difference between the top of the bonding layer and the top of the insulating block is less than 15 μm.

15. The photovoltaic module of any of claims 1-9, wherein, The number of the electrical interconnections is multiple, the head of at least one electrical interconnection protrudes from the bonding layer, or the head of at least one electrical interconnection is located in the 2 / 3 area of the bonding layer away from the tail of the electrical interconnection.

16. The photovoltaic module of any of claims 1-9, wherein, The electrical interconnection is a wire, the bonding layer comprises an alloy material located on the outer periphery of the wire, and / or an alloy material located between the wire and the grid line.

17. The photovoltaic module of any of claims 1-9, wherein, A first alloy connecting layer is formed between the bonding layer and the grid line, and a second alloy connecting layer is formed between the bonding layer and the electrical interconnection.

18. The photovoltaic module of any of claims 1-9, wherein, The bottom of the bonding layer is fixed with the electrical interconnection, and the bonding layer covers at least part of the side surface of the electrical interconnection.

19. The photovoltaic module of any of claims 1-9, wherein, The cross section of the grid line has a hole, the length of the hole in the cross section of the grid line is less than or equal to 60% of the size of the grid line in the direction of the length of the hole, and the length of the hole is the maximum size of the hole in the cross section of the grid line.

20. A photovoltaic system, wherein, The photovoltaic support and a plurality of photovoltaic modules according to any one of claims 1 to 19. The photovoltaic support and a plurality of photovoltaic modules according to any one of claims 1 to 19.

21. A method of producing a photovoltaic module, wherein, ​ A bonding layer is arranged on the grid lines on the surface of the battery piece; The electrical interconnection is welded on the grid lines through the bonding layer; wherein, during the welding process, the welding temperature is greater than the melting point of the bonding layer, less than or equal to 130% of the melting point of the bonding layer, and the welding time is greater than or equal to 1700 milliseconds and less than 2800 milliseconds.

22. A method of producing a photovoltaic module, wherein, Comprise: A bonding layer is arranged on the grid lines on the surface of the battery piece; The electrical interconnection is pre-fixed on the bonding layer, and the electrical interconnection is connected with the grid lines through the bonding layer during the laminating process; during the laminating process, the laminating temperature is greater than 78% of the melting point of the bonding layer and less than or equal to 130% of the melting point of the bonding layer, and / or the laminating pressure is greater than 40 kilopascals and less than or equal to 80 kilopascals.

23. The method of producing a photovoltaic assembly according to claim 22, wherein, The pre-fixing includes at least one of the following modes: fixing a film, fixing a tape, insulating glue, and conductive glue.

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