A composite busbar for photovoltaic modules and photovoltaic modules

Abstract

This invention provides a composite busbar for photovoltaic modules and a photovoltaic module. The composite busbar for photovoltaic modules includes a conductive substrate and a welded coating encapsulating the conductive substrate. The conductive substrate comprises multiple layers of deformable conductive layers stacked together and deformable filler layers filling the spaces between each pair of adjacent deformable conductive layers. Under conditions equal to or higher than a predetermined temperature, the hardness of the deformable filler layers is less than the hardness of the deformable conductive layers. Because this composite busbar for photovoltaic modules includes multiple layers of deformable conductive layers, the thickness of each deformable conductive layer is reduced. Furthermore, the hardness of the deformable filler layers filling the spaces between each pair of adjacent deformable conductive layers is less than the hardness of the deformable conductive layers, thus reducing the hardness of the composite busbar. This solves the problems of glass breakage and microcracks in solar cells that occur during the manufacturing and use of photovoltaic modules due to excessively high busbar hardness.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic module technology, and in particular to a composite busbar and a photovoltaic module. Background Technology

[0002] Currently, photovoltaic modules use solder ribbons to connect solar cells in series to form a cell string. Busbars are then connected to the solder ribbons to collect and transmit the current from the cell string to the outside. Conventional busbars used in current technology are typically made by coating a single copper strip with a solderable tin alloy coating. On one hand, to meet the current-carrying capacity requirements, the busbar needs a certain cross-sectional area, resulting in high rigidity. On the other hand, the overall thickness of the welded area after welding the busbar to the solder ribbon is greater than the sum of the busbar thickness and the solder ribbon thickness. During lamination, the busbar is prone to contact with the glass, causing the glass to break. Utility Model Content

[0003] In view of this, the present invention provides a composite busbar and a photovoltaic module for use in photovoltaic modules. This not only reduces the hardness of the composite busbar, but also reduces the overall thickness of the welding area after the busbar is welded to the solder strip. This reduces the problems of glass breakage and microcracks in the cells during the lamination process, improves the reliability of the photovoltaic module, and extends the service life of the photovoltaic module.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] In a first aspect, this utility model provides a composite busbar for photovoltaic modules, comprising a conductive substrate and a welding coating encapsulating the conductive substrate, wherein the conductive substrate comprises multiple layers of deformable conductive layers stacked together and a deformable filler layer filling between every two adjacent deformable conductive layers, and the hardness of the deformable filler layer is less than the hardness of the deformable conductive layer under conditions equal to or higher than a predetermined temperature.

[0006] Optionally, the deformable filler layer melts into a liquid at a temperature equal to or higher than the predetermined temperature.

[0007] Optionally, the deformable conductive layer is press-sealed against each other around its perimeter.

[0008] Optionally, the predetermined temperature is lower than the welding temperature between the composite busbar and the welding strip.

[0009] Optionally, the predetermined temperature is lower than the lamination temperature of the photovoltaic module.

[0010] Optionally, the deformable conductive layer has 2 to 9 layers, and the deformable filling layer has 1 to 8 layers.

[0011] Optionally, the thickness of the deformable conductive layer is 0.01mm-0.2mm, and the thickness of the deformable filler layer is 0.05mm-0.2mm.

[0012] Optionally, the deformable conductive layer is made of copper, silver, or gold; the deformable filling layer is made of graphene or carbon nanotubes.

[0013] Secondly, this utility model provides a photovoltaic module, including: a plurality of solar cells, a solder strip, and a composite busbar provided in the first aspect, wherein the plurality of solar cells are connected in series through the solder strip, and the solder strip is electrically connected to the composite busbar.

[0014] Optionally, the solder strip is at least partially embedded in the composite busbar, such that the thickness of the welding area between the composite busbar and the solder strip is less than the sum of the thickness of the composite busbar and the thickness of the solder strip.

[0015] According to the first aspect of the present invention, a composite busbar for photovoltaic modules is provided, comprising a conductive substrate and a welded coating encapsulating the conductive substrate. The conductive substrate comprises multiple layers of deformable conductive layers stacked together and deformable filler layers filling the spaces between each pair of adjacent deformable conductive layers. Under conditions equal to or higher than a predetermined temperature, the hardness of the deformable filler layer is less than the hardness of the deformable conductive layer. Because the composite busbar comprises multiple layers of deformable conductive layers, the thickness of each layer is reduced. Furthermore, the hardness of the deformable filler layer filling the gaps between each pair of adjacent deformable conductive layers is less than the hardness of the deformable conductive layer under conditions equal to or higher than a predetermined temperature. This reduces the overall hardness of the composite busbar, promoting its deformation. By reducing the hardness of the composite busbar, the problems of glass breakage and microcracks in solar cells caused by excessively high busbar hardness during photovoltaic module manufacturing and use are solved, improving the reliability of the photovoltaic module and extending its service life.

[0016] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0017] The accompanying drawings are provided to better understand this utility model and do not constitute an undue limitation thereof. Wherein: Figure 1 This is a schematic diagram of the structure of a welded component formed by welding a conventional busbar and a welding strip; Figure 2 This is a schematic diagram of the structure of a composite busbar according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the composite busbar after pressing together on both sides according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a welded component formed by welding a composite busbar and a welding strip according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the laminated and welded part of a photovoltaic module according to an embodiment of the present invention.

[0018] The attached figures are labeled as follows: 1-Conventional busbar; 11-Copper strip; 12-Tin plating layer; 2-Solder strip; 3-Composite busbar; 30-Conductive substrate; 31-Deformable conductive layer; 32-Solder coating; 33-Deformable filler layer. Detailed Implementation

[0019] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These embodiments should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0020] Figure 1 This is a schematic diagram of the structure of a welded component formed by welding a conventional busbar and a welding strip. For example... Figure 1 As shown, the conventional busbar 1 consists of two parts: a single copper strip 11 and a tin-plated layer 12 coated on its surface. When the conventional busbar 1 is soldered to the solder strip 2, tin buildup or bulges will form on the surface of the conventional busbar 1, making the maximum thickness (i.e., the thickness of the soldering area) H of the welded part formed by the conventional busbar 1 and the solder strip 2 larger than expected. Generally, H ≥ T1 + T2, where T1 is the thickness of the solder strip 2 and T2 is the thickness of the conventional busbar 1.

[0021] In practical applications, due to requirements on the cross-sectional area of ​​the busbar, conventional busbars typically have high rigidity, which presents the following problems: 1. The maximum thickness of the welded part formed by welding the busbar and the welding strip is too large, and the welded part is very easy to come into contact with the glass, causing the glass to break. 2. When the busbar is hidden or directly welded to the back of the battery cell, microcracks may occur in the battery cell during the lamination process due to the excessive hardness of the busbar. 3. During the lamination process, the high hardness of the busbar prevents the encapsulating film on the front and back of the busbar area from being fully filled between the glass and the busbar area. This causes the solder strip or busbar to come into direct contact with the glass, resulting in problems such as glass breakage and microcracks in the cells after the photovoltaic module is completed or during testing.

[0022] In summary, due to the excessive hardness of conventional busbars and the high overall thickness of the welded area after welding with the solder strip, glass breakage and microcracks in the cells are prone to occur during the manufacturing and use of photovoltaic modules, directly affecting the reliability and service life of photovoltaic modules.

[0023] To address at least one of the aforementioned technical problems, this invention provides a composite busbar for photovoltaic modules. It is composed of multiple deformable conductive layers and deformable filler layers with lower hardness filling the gaps between adjacent deformable conductive layers. Compared to conventional busbars of the same thickness, it has lower hardness because: firstly, the deformable conductive layers are multiple, reducing the thickness of each layer; secondly, the deformable filler layers filling the gaps between adjacent deformable conductive layers have lower hardness than the deformable conductive layers at temperatures equal to or above a predetermined temperature, thus reducing the overall hardness of the composite busbar at these temperatures. Furthermore, since the composite busbar of this invention includes multiple deformable conductive layers, the multi-layer structure effectively ensures the overall performance of the composite busbar, allowing each deformable conductive layer to be made of a material with even lower hardness, further reducing the hardness of the composite busbar. By reducing the hardness of the composite busbar, the problems of glass breakage and microcracks in solar cells caused by excessive busbar hardness during the manufacturing and use of photovoltaic modules are solved, thereby improving the reliability of photovoltaic modules and extending their service life.

[0024] Under conditions equal to or higher than a predetermined temperature, the deformable filler layer 33 can melt into a liquid and flow; under external stress, the deformable conductive layer 31 deforms. The flow of the melted deformable filler layer 33 reduces the resistance to deformation of the deformable conductive layer 31, thereby reducing the deformation resistance of the deformable conductive layer 31 and making the deformation of the composite busbar easier.

[0025] The predetermined temperature can be lower than the welding temperature when the composite busbar 3 is welded to the solder strip 2. This allows the deformable filler layer to melt as the welding fixture presses down during the welding of the composite busbar and the solder strip. This causes the deformable filler layer in the welding area to flow and distribute to the non-welding area, reducing the deformation resistance of the deformable conductive layer 31. The overall deformation of the composite busbar forms a concave wrap around the solder strip. On the one hand, this reduces the thickness of the welding area, preventing the solder strip or composite busbar from contacting the glass and causing it to break. On the other hand, it increases the contact area between the composite busbar and the solder strip, allowing for full welding of the solder strip without the need for additional flux or solder, effectively improving the welding pull force.

[0026] In addition, the predetermined temperature can be lower than the lamination temperature of the photovoltaic module, so that during the lamination process, under the action of high temperature and overall pressure, the deformable filler layer melts and flows from the area of ​​high stress in the composite busbar to the area of ​​low stress in the composite busbar. The deformable conductive layer 31 further deforms, which can not only increase the deformation of the composite busbar, but also further reduce the overall height of the composite busbar and further reduce the maximum thickness of the welding area. In this way, the probability of direct contact between the solder strip or the composite busbar and the glass can be further reduced, thereby avoiding glass breakage caused by contact between the solder strip or the composite busbar and the glass.

[0027] Figure 2 This is a schematic diagram of the structure of a composite busbar according to an embodiment of this utility model. Figure 2 As shown, in one embodiment of the present invention, the composite busbar 3 includes a conductive substrate 30 and a welding coating 32 that wraps around the conductive substrate 30. The conductive substrate 30 includes multiple layers of deformable conductive layers 31 stacked together and a deformable filler layer 33 filling between every two adjacent deformable conductive layers 31. Under conditions equal to or higher than a predetermined temperature, the hardness of the deformable filler layer 33 is less than the hardness of the deformable conductive layer 31.

[0028] According to one embodiment of the present invention, adjacent deformable conductive layers 31 and deformable filler layers 33 abut against each other. This minimizes the thickness of the composite busbar and improves its conductivity.

[0029] In practical implementation, the deformable conductive layer 31 can be made of a metal material with good electrical and thermal conductivity, such as copper, silver, or gold. Since the deformable conductive layer 31 of this invention has multiple layers (two or more), and a deformable filler layer 33 fills the gaps between every two adjacent deformable conductive layers 31, each deformable conductive layer 31 is relatively thin. In one embodiment, taking a composite busbar 3 comprising three deformable conductive layers 31 as an example, if the total thickness of the composite busbar 3 is, for example, 0.4 mm, then the thickness of a single deformable conductive layer 31 is approximately less than 0.1 mm, far less than the thickness of the entire copper strip 11 of a conventional busbar 1. There are gaps between the multiple deformable conductive layers 31 inside the composite busbar 3. These gaps are filled with deformable filler layers 33, which have a hardness less than that of the deformable conductive layers 31 under conditions equal to or higher than a predetermined temperature. The deformable filler layers 33 are, for example, low-temperature solder or thermoplastic conductive resin, materials with low hardness, such as graphene or carbon nanotubes. A welding coating 32 is applied to the outer surface of the conductive substrate, wherein the welding coating 32 is, for example, a tin plating layer.

[0030] According to an embodiment of the present invention, since the composite busbar includes multiple deformable conductive layers, the thickness of each deformable conductive layer is reduced, and the hardness of the deformable filler layer filling the gap between every two adjacent deformable conductive layers is less than the hardness of the deformable conductive layer under conditions equal to or higher than a predetermined temperature, thus reducing the hardness of the composite busbar.

[0031] Figure 3 This is a schematic diagram of the structure of a composite busbar after pressing together on both sides according to an embodiment of the present invention. After the composite busbar 3 is obtained by stacking and laying the deformable conductive layer 31 and the deformable filler layer 33 as described above, a seal is formed around the composite busbar 3. That is, the deformable conductive layers 31 are pressed together on all sides, forming a sealed gap between adjacent deformable conductive layers 31. The deformable filler layer 33 fills the sealed gap, and the welding coating layer 32 covers the outermost layer. Figure 3 The cross-sectional view of the composite busbar 3 shown is perpendicular to its length. This prevents the deformable filler layer 33 from overflowing during welding or lamination, which would affect the conductivity of the composite busbar 3. For the two edges of the composite busbar 3 along its length, the sealing method can be determined according to the specific shape of the composite busbar 3.

[0032] According to another embodiment of this utility model, when the composite busbar 3 is a roll material, deformable conductive layers 31 are pressed and sealed together at both ends along the length direction and both sides along the width direction of the composite busbar 3. After cutting during use, the cut edges are sealed with an edge-sealing layer, the melting point of which is higher than the lamination temperature of the photovoltaic module. In one embodiment, the melting point of the edge-sealing layer is above 200°C. In specific implementation, the edge-sealing layer can be achieved using a high-melting-point solder, the melting point of which is higher than the lamination temperature of the photovoltaic module. In one embodiment, to facilitate the cutting and use of the composite busbar 3, the two edges along the length direction of the composite busbar 3 can be left untreated temporarily. After each cut, the two edges along the length direction of the cut composite busbar 3 are sealed with a high-melting-point solder. Among them, the melting point of the high-melting-point solder must be higher than the lamination temperature of the photovoltaic module. Under normal circumstances, the lamination temperature is 140℃-150℃, and a high-melting-point solder with a melting point of 200℃ or higher can be selected. By making the melting point of the sealing layer higher than the lamination temperature of the photovoltaic module, it can be ensured that the composite busbar 3 remains in a sealed state during the lamination process, avoiding leakage of the deformable filler layer 33.

[0033] According to an embodiment of this utility model, the gap between every two adjacent deformable conductive layers 31 inside the composite busbar 3 is filled with a deformable filler layer 33. The deformable filler layer 33 is, for example, a low-temperature solder or a thermoplastic conductive resin. The melting temperature of the deformable filler layer 33 is lower than the welding temperature when the composite busbar 3 is welded to the solder strip 2. Typically, the melting temperature of the deformable filler layer 33 is 100℃-120℃, and the welding temperature is 200℃-400℃. By setting the melting temperature of the deformable filler layer 33 below the welding temperature when welding the composite busbar 3 and the solder strip 2, the deformable filler layer 33 can be melted at high temperature as the welding fixture presses down during the welding process. This allows the deformable filler layer 33 in the welding area to flow and distribute to the non-welding area, forming a concave wrapping around the solder strip 2. On the one hand, this reduces the thickness of the welding area, preventing the solder strip 2 or the composite busbar 3 from contacting the glass and causing it to break. On the other hand, it increases the contact area between the composite busbar 3 and the solder strip 2, allowing for full welding of the solder strip 2 without the need for additional flux or solder, effectively improving the welding pull strength.

[0034] Figure 4 This is a schematic diagram of the structure of a welded component formed by welding a composite busbar and solder strip according to an embodiment of this utility model. During the welding process of the composite busbar 3 and solder strip 2, under the downward pressure of the welding fixture and the high temperature of welding, the deformable filler layer 33 in the welding area melts and flows to the non-welding area, forming a depression under the solder strip 2 in the welding area. The composite busbar 3 wraps around the solder strip 2, thereby increasing the contact area between the composite busbar 3 and the solder strip 2. Full welding of the solder strip 2 can be achieved without adding additional flux or solder, improving the welding tensile strength and welding effect, and solving the problem of low tensile strength of low-diameter solder strip 2. At this point, the thickness H1 of the weld zone formed by the composite busbar 3 and the welding strip 2 is less than the sum of the thickness of the composite busbar 3 and the thickness of the welding strip 2, i.e., H1 < T1 + T2, where T1 is the thickness of the welding strip 2 and T2 is the thickness of the composite busbar 3 (for ease of comparison between the composite busbar 3 and the conventional busbar 1, the thicknesses of the composite busbar 3 and the conventional busbar 1 are the same in this embodiment). It can be seen that after the composite busbar 3 and the welding strip 2 are welded, the weld zone thickness H1 is less than the weld zone thickness H of the welded part formed by the conventional busbar 1 and the welding strip 2. Therefore, using the composite busbar 3 provided by this invention can reduce the weld zone thickness, thereby preventing the welding strip 2 or the composite busbar 3 from contacting the glass and causing it to break.

[0035] According to another embodiment of the present invention, the melting temperature of the deformable filler layer 33 is lower than the lamination temperature of the photovoltaic module. This allows the deformable filler layer 33 to melt and flow to the non-welding area under the action of high temperature and overall pressure during the lamination process, further reducing the thickness of the welding area of ​​the welded parts after the photovoltaic module is laminated. This further reduces the probability of the solder ribbon 2 or composite busbar 3 coming into direct contact with the glass, thus avoiding glass breakage caused by contact between the solder ribbon 2 or composite busbar 3 and the glass.

[0036] Figure 5 This is a schematic diagram of the structure of a photovoltaic module laminated and welded component according to one embodiment of this utility model. Figure 5 As shown, during the photovoltaic module lamination process, under the lamination pressure and high temperature, the deformable filler layer 33 inside the composite busbar 3 can remelt and flow to other non-welded areas. These other non-welded areas are farther from the welding area and have more space compared to the aforementioned non-welded areas. Since the lamination process involves overall stress, the deformable filler layer 33 inside the composite busbar 3 can be more evenly distributed to other non-welded areas, making the overall height of the composite busbar 3 more uniform and further reducing the height of the welding area. At this time, the thickness H2 of the welding area after photovoltaic module lamination is less than the thickness H1 of the welding area after the composite busbar 3 is welded to the solder strip 2, i.e., H2 < H1. Therefore, using the composite busbar 3 provided by this utility model to perform photovoltaic module lamination can further reduce the thickness of the welding area, further reducing the probability of hard contact between the solder strip 2 or the composite busbar 3 and the glass, and avoiding glass breakage caused by contact between the solder strip 2 or the composite busbar 3 and the glass.

[0037] Meanwhile, since the composite busbar 3 has a lower hardness than the conventional busbar 1, it can better ensure that the front and back encapsulation films of the busbar area are fully filled between the glass and the busbar area, avoiding direct contact between the solder strip 2 or the composite busbar 3 and the glass. This further avoids problems such as glass breakage and cell microcracks in the finished photovoltaic module after production or during testing.

[0038] According to embodiments of this utility model, busbars of different widths and thicknesses are used depending on the size and power of the photovoltaic module and the current carried by the busbar in the circuit. Typically, the width of the composite busbar 3 used can be 3mm-20mm, and the thickness can be 0.07mm-0.5mm. During the specific manufacturing process of the composite busbar 3, due to the influence of the manufacturing process, the number of deformable conductive layers 31 can be set to 2-9 layers, and correspondingly, the number of deformable filling layers 33 can be set to 1-8 layers. The thickness of each deformable conductive layer 31 ranges from 0.01mm to 0.2mm, and the thickness of each deformable filling layer 33 ranges from 0.05mm to 0.2mm. In specific applications, different numbers of deformable conductive layers, deformable filling layers, deformable conductive layer thicknesses, and deformable filling layer thicknesses can be selected as needed.

[0039] According to other embodiments of the present invention, the deformable filling layer 33 can be, for example, graphene, carbon nanotubes or other organic or inorganic superconducting materials. These materials have good electrical and thermal conductivity, which can meet the requirements of current carrying and heat dissipation, and can optimize the conductivity of the composite busbar 3 while reducing the hardness of the composite busbar 3.

[0040] Furthermore, this embodiment of the present invention also provides a photovoltaic module, which includes multiple solar cells, solder ribbons, and a composite busbar 3 as described in the foregoing embodiments of the present invention. The multiple solar cells are electrically connected to form a solar cell string via solder ribbons 2, and the solder ribbons 2 are electrically connected to the composite busbar 3.

[0041] like Figure 4 and Figure 5As shown, the solder strip 2 is at least partially embedded in the composite busbar 3, such that the thickness of the welding area between the composite busbar 3 and the solder strip 2 is less than the sum of the thickness of the composite busbar 3 and the thickness of the solder strip 2. Specifically, during the welding process, the composite busbar 3 deforms, forming a groove under the pressure of the solder strip 2, and the solder strip 2 is embedded and welded into the groove. Furthermore, in one embodiment, the conductive segments of the multilayer deformable conductive layers 31 of the composite busbar 3 corresponding to the grooves are at least partially abutting each other. Since the melting temperature of the deformable filler layer 33 is lower than the welding temperature when the composite busbar 3 is welded to the solder strip 2, the deformable filler layer 33 can be melted at high temperature as the welding fixture is pressed down during the welding of the composite busbar 3 and the solder strip 2. This allows the deformable filler layer 33 in the welding area to flow and distribute to the non-welding area, so that the deformable conductive layers 31 of the composite busbar 3 can at least partially abut against each other. At the same time, since the melting temperature of the deformable filler layer 33 is lower than the lamination temperature of the photovoltaic module, the deformable filler layer 33 can be further melted and flowed and distributed to the non-welding area under the action of high temperature and overall pressure during the lamination process, so that the deformable conductive layers 31 of the composite busbar 3 can at least partially abut against each other.

[0042] The photovoltaic modules formed by the above process have a welding zone thickness that is much smaller than the welding zone thickness of conventional busbar 1 and welding strip 2. This reduces the probability of welding strip 2 or composite busbar 3 coming into direct contact with the glass, thus avoiding glass breakage caused by contact between welding strip 2 or composite busbar 3 and the glass.

[0043] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A composite busbar for use in photovoltaic modules, characterized in that, It includes a conductive substrate (30) and a welding coating (32) encapsulating the conductive substrate (30), wherein, The conductive substrate (30) includes multiple layers of deformable conductive layers (31) stacked together and a deformable filler layer (33) filling between every two adjacent deformable conductive layers (31). Under conditions equal to or higher than a predetermined temperature, the hardness of the deformable filler layer (33) is less than the hardness of the deformable conductive layer (31).

2. The composite busbar according to claim 1, characterized in that, Under conditions equal to or higher than the predetermined temperature, the deformable filler layer (33) melts into a liquid.

3. The composite busbar according to claim 1, characterized in that, The deformable conductive layer (31) is press-sealed against each other around its perimeter.

4. The composite busbar according to claim 2, characterized in that, The predetermined temperature is lower than the welding temperature of the composite busbar (3) and the welding strip (2).

5. The composite busbar according to claim 2, characterized in that, The predetermined temperature is lower than the lamination temperature of the photovoltaic module.

6. The composite busbar according to claim 1, characterized in that, The deformable conductive layer (31) has 2 to 9 layers. The deformable filling layer (33) has 1 to 8 layers.

7. The composite busbar according to claim 1, characterized in that, The thickness of the deformable conductive layer (31) is 0.01mm-0.2mm. The thickness of the deformable filler layer (33) is 0.05mm-0.2mm.

8. The composite busbar according to claim 1, characterized in that, The deformable conductive layer (31) is made of copper, silver or gold; The deformable filling layer (33) is made of graphene or carbon nanotubes.

9. A photovoltaic module, characterized in that, include: Multiple battery cells, solder strips (2), and composite busbars (3) as described in any one of claims 1-8. The multiple battery cells are connected in series via the welding strip (2), and the welding strip (2) is electrically connected to the composite busbar (3).

10. The photovoltaic module according to claim 9, characterized in that, The welding strip (2) is at least partially embedded in the composite busbar (3), such that the thickness of the welding area between the composite busbar (3) and the welding strip (2) is less than the sum of the thickness of the composite busbar (3) and the thickness of the welding strip (2).

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