Photovoltaic module

Abstract

The utility model provides a kind of photovoltaic module, photovoltaic module includes: multiple cell pieces, interconnecting strip and bus bar;Multiple cell pieces are arrayed along first direction and second direction;Along first direction, interconnecting strip is welded to form cell string with multiple cell pieces, along second direction, bus bar is welded to form battery pack with cell string;Interconnecting strip includes conductive core body and conductive cladding, and conductive cladding is set to the outside of conductive core body, and it is wrapped conductive core body, wherein, the material of conductive core body and conductive cladding is different.Interconnecting strip uses different material conductive core body and conductive cladding, and conductive core body can select more economical material, and conductive cladding can select material of excellent conductivity, can simultaneously give consideration to current transmission efficiency and practical application adaptability;On the premise that the conductive performance of core body meets the current transmission demand, by selecting cost-effective conductive core body, reduce the production raw material cost of interconnecting strip, and then reduce the cost of entire photovoltaic module.

Description

Technical Field

[0001] This utility model belongs to the field of solar cell technology, specifically relating to a photovoltaic module. Background Technology

[0002] In a back-contact battery, both the positive and negative electrodes are located on the back side and are arranged in an interlaced pattern to avoid the positive and negative grid lines from blocking the front side of the cell, thereby improving the photoelectric conversion efficiency of the cell.

[0003] Current back-contact battery modules generally suffer from high costs. How to reduce the manufacturing cost of back-contact battery modules while ensuring the quality and power generation efficiency of back-contact batteries is a problem that needs to be solved. Utility Model Content

[0004] This utility model provides a photovoltaic module to solve the problem of high cost of back-contact batteries while ensuring the module's power generation efficiency.

[0005] To solve the above-mentioned technical problems, this utility model is implemented as follows: This application provides a photovoltaic module, which includes: multiple solar cells, interconnecting strips, and busbars; The plurality of solar cells are arranged in an array along a first direction and a second direction; the photovoltaic module has a third direction, which is perpendicular to the plane formed by the first direction and the second direction. Along the first direction, the interconnecting strip welds multiple battery cells to form a battery string; along the second direction, the busbar welds the battery string to form a battery pack. The interconnecting strip includes a conductive core, a conductive coating, and a first welding layer. The conductive coating is disposed outside the conductive core and wraps around the conductive core. The first welding layer is disposed outside the conductive coating and wraps around the conductive coating. The busbar includes a substrate and a second welding layer, wherein the second welding layer is disposed on the outside of the substrate; The first welding layer and the second welding layer are welded together to form a bonding layer, and the interconnecting strip and the busbar are electrically connected through the bonding layer; The conductive coating and the substrate are made of a first conductive material, and the conductive core is made of a second conductive material. The resistivity of the first conductive material is less than that of the second conductive material.

[0006] Optionally, along the third direction, the thickness d of the middle region of the conductive core is less than the thickness d of the two sides; and / or, The thickness c of the middle region of the conductive coating is greater than the thickness c of the two side regions.

[0007] Optionally, along the third direction, the thickness c of the conductive coating and the thickness d of the conductive core satisfy the following relationship: 0.1 ≤ c / d ≤ 0.17; and / or, The thickness c of the conductive coating satisfies: 10μm ≤ c ≤ 50; and / or, The thickness d of the conductive core satisfies: 100μm≤d≤300μm.

[0008] Optionally, along the third direction, the thickness a of the busbar substrate and the thickness c of the conductive coating satisfy the following relationship: 7 ≤ a / c ≤ 10.

[0009] Optionally, along the third direction, the base material thickness of the busbar is a, 0.1mm≤a≤0.35mm, and the thickness of the interconnecting strip is b, 0.1mm≤b≤0.3mm, and a and b satisfy: a / b≤1.16.

[0010] Optionally, the thickness of the middle region of the bonding layer along the third direction is greater than the thickness of the two side regions along the third direction.

[0011] Optionally, along the third direction, the thickness of the middle region of the bonding layer is greater than the thickness of the two side regions, and the thickness of the bonding layer is D; The thickness of the middle region of the first weld layer is greater than the thickness of the two side regions. The thickness of the first weld layer is D1, and the thickness of the second weld layer is D2, where D > D1 or D > D2.

[0012] Optionally, the thickness of the first weld layer in the middle region along the third direction is greater than the thickness of the two side regions.

[0013] Optionally, along the second direction, the width of the bonding layer is greater than the width of the interconnecting strip.

[0014] Optionally, the first welding layer and the second welding layer are made of the same material.

[0015] Optionally, the busbar is disposed between the interconnecting bar and the battery cell; The busbar is provided with multiple conductive parts and insulating parts, and the conductive parts and the insulating parts are arranged at intervals. The interconnecting strip is welded to the conductive part.

[0016] Optionally, the busbar is disposed on the interconnecting bar, and the interconnecting bar is located between the busbar and the battery cell; An insulating layer is further provided between the busbar and the interconnecting bar; The insulating layer has multiple welding holes, and the busbar is welded to the interconnecting strip through the welding holes.

[0017] Optionally, the busbar includes an edge busbar and a middle busbar; The edge busbars are disposed at both ends of the photovoltaic module along the first direction, and the middle busbar is disposed between the two edge busbars; Along the first direction, the width of the intermediate busbar is e, and the width of the edge busbar is f, (ef) ≥ 0.5 mm.

[0018] Optionally, the battery cell includes: a first grid line and a second grid line, and the interconnecting strip includes a first interconnecting strip and a second interconnecting strip; The first gate line and the second gate line have opposite polarities and are spaced apart. The first interconnecting strip is welded to the first gate line, and the second interconnecting strip is welded to the second gate line. A first insulating portion is provided at the position where the first interconnecting strip contacts the second grid line, and a second insulating portion is provided at the position where the second interconnecting strip contacts the first grid line. Insulating adhesive is provided on the first insulating portion and the second insulating portion. Along the second direction, the widths of the first insulating portion and the second insulating portion are greater than the width of the interconnecting strip.

[0019] Optionally, along the third direction, the cross-section of the interconnecting strip is rectangular, rounded rectangular, or elliptical.

[0020] In this embodiment, the design of welding battery cells into battery strings using interconnecting strips along the first direction and welding battery strings into battery packs using busbars along the second direction creates an efficient current collection and transmission path: the interconnecting strips can accurately connect adjacent battery cells, reduce current loss between individual battery cells, and ensure that the electrical energy generated by each battery cell is efficiently fed into the battery string; the busbars further integrate the current of multiple battery strings, reduce the impedance of current transmission between strings, avoid power loss caused by local current accumulation, and ultimately improve the power generation efficiency of the entire module. The interconnecting strips employ a composite structure composed of conductive cores and conductive coatings made of different materials. The conductive cores can be made of more economical materials, while the conductive coatings can be made of materials with excellent conductivity. This balances current transmission efficiency with practical application adaptability, ensuring the low resistance characteristics of the core current transmission channel and reducing heat loss during power transmission. While ensuring that the conductivity of the core meets the current transmission requirements, the use of cost-effective conductive cores reduces the raw material cost of the interconnecting strips, thereby reducing the overall cost of the photovoltaic module. The busbars are made of materials with excellent conductivity, ensuring the transmission effect of a larger current collected from the cells by the welding ribbon, thus guaranteeing the power generation efficiency and power of the module. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a photovoltaic module provided in an embodiment of this application; Figure 2 This is a schematic diagram of an interconnecting strip and a busbar welded together, provided in an embodiment of this application. Figure 3 This is a cross-sectional schematic diagram of an interconnecting strip along the Z direction provided in an embodiment of this application; Figure 4 This is a cross-sectional view of another interconnecting strip along the Z direction provided in an embodiment of this application; Figure 5 This is a top view of a photovoltaic module welding method provided in an embodiment of this application; Figure 6 yes Figure 5 A cross-sectional view at position AA along the middle edge; Figure 7 This is a top view of another photovoltaic module welding method provided in the embodiments of this application; Figure 8 yes Figure 7 A cross-sectional view along the BB position; Figure 9 This is a schematic diagram of the welding of interconnect strips and grid lines in a photovoltaic module provided in the embodiments of this application.

[0022] Explanation of reference numerals in the attached figures: 10. Battery cell; 20. Interconnect strip; 201. Conductive core; 2011. First side; 2012. Second side; 202. Conductive coating; 203. First welding layer; 204. First interconnect strip; 2041. First insulating part; 205. Second interconnect strip; 2051. Second insulating part; 30. Busbar; 301. Substrate; 302. Second welding layer; 303. Conductive part; 304. Insulating part; 305. Edge busbar; 306. Middle busbar; 40. Battery string; 50. Bonding layer; 60. Insulating layer; 601. Welding hole; 70. First grid line; 80. Second grid line; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0024] The terms "first," "second," etc., used in the specification and claims of this utility model are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this utility model can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, the first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] The embodiments of this utility model will be described in detail below with reference to the accompanying drawings, through specific examples and application scenarios.

[0026] This application provides a photovoltaic module, referencing... Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a photovoltaic module omitting the insulation layer. The photovoltaic module includes: multiple solar cells 10, interconnecting strips 20, and busbars 30; the multiple solar cells 10 are arranged in an array along a first direction X and a second direction Y; the photovoltaic module has a third direction Z, which is perpendicular to the plane formed by the first direction X and the second direction Y; along the first direction X, the interconnecting strips 20 weld the multiple solar cells 10 to form a cell string 40, and along the second direction Y, the busbars 30 weld the cell strings 40 to form a battery pack; the interconnecting strips 20 include a conductive core 201, a conductive coating 202, and a first welding layer 203, the conductive coating 202 being disposed outside the conductive core 201 and wrapping the conductive core 201. The first welding layer 203 is disposed on the outside of the conductive cover 202 and wraps the conductive cover 202. The conductive core 201, the conductive cover 202 and the first welding layer 203 are all made of different materials. The busbar 30 includes a substrate 301 and a second welding layer 302, which is disposed on the outside of the substrate 301. The first welding layer 203 and the second welding layer 302 are welded to form a bonding layer 50. The interconnecting strip 20 and the busbar 30 are electrically connected through the bonding layer 50. The conductive cover 202 and the substrate 301 are made of a first conductive material, and the conductive core 201 is made of a second conductive material. The resistivity of the first conductive material is less than that of the second conductive material.

[0027] Multiple battery cells 10 are arranged in an array along a first direction X and a second direction Y. That is, the battery cells 10 are arranged into an array after being welded together by interconnecting strips 20 and busbars 30. The interconnecting strips 20 are made of an alloy composed of a conductive core 201 and a conductive coating 202, and then wrapped with a first welding layer 203. Without affecting conductivity, the conductive core 201 can be made of a cheaper material, while the outer conductive coating 202 can be made of a more reliable material, ensuring conductivity while reducing costs. Finally, another first welding layer 203 is wrapped on the outside. The first welding layer 203 is made of a material with a low melting point and easy welding. Welding is achieved by the first welding layer 203 to the battery cells 10 and the busbars 30. The busbars 30 are composed of a substrate 301 and a second welding layer 302. The substrate 301 is made of a material with high conductivity and low resistance loss, and the second welding layer 302 is made of a material with a low melting point and easy welding.

[0028] In actual production, copper, silver, or an alloy of at least one of these materials with other materials can be used as the conductive coating 202 to wrap around the conductive core 201. The conductive core 201 can be made of aluminum, manganese, lead, or an alloy of at least one of these materials with other materials. The first welding layer 203 can be made of tin-lead alloy or tin-lead-bismuth alloy. Because aluminum is cheaper, it is preferred for the conductive core 201, which can significantly reduce the cost of the interconnect strip 20 and improve the economic efficiency of the photovoltaic module. The substrate 301 can preferably be made of copper, and the second welding layer 302 can preferably be made of tin-lead alloy or tin-lead-bismuth alloy.

[0029] Currently, the purchase price of high-purity aluminum (purity ≥99.7%) is only 1 / 3 to 1 / 4 of that of high-purity copper (purity ≥99.99%). Furthermore, aluminum's density is approximately 2.7 g / cm³, while copper's is approximately 8.96 g / cm³, meaning aluminum's density is about 30% of copper's. In interconnect strips of the same specifications (e.g., 20), the material cost per aluminum core can be reduced by 60% to 70% compared to copper cores. Simultaneously, although aluminum has a conductivity of approximately 37 × 10⁻⁶... 6 S / m, lower than copper by approximately 58 × 10⁻⁶. 6 While the conductivity is S / m, by optimizing the thickness, length, and width of the core, the cross-sectional area of ​​the core can be optimized, which can compensate for the increase in resistance caused by insufficient conductive cross-sectional area. This ensures that the conductivity of the aluminum core meets the current transmission requirements of the photovoltaic module and avoids a significant increase in power loss due to the replacement of the core material.

[0030] Using a tin-lead alloy as the first welding layer 203 and the second welding layer 302 significantly improves the welding quality of the interconnect strips and busbars, ensuring the stability of the bonding layer 50. The tin-lead alloy has a low melting point, or even a tin-lead-bismuth alloy with an even lower melting point. During welding, it easily melts and fully wets the surfaces of the copper conductive cladding 202 and the copper substrate 301, forming a tight metallurgical bond and avoiding problems such as incomplete or false soldering. Simultaneously, the tin-lead alloy exhibits good ductility after cooling, adapting to the thermal expansion and contraction stress caused by diurnal temperature variations when photovoltaic modules are used outdoors, reducing the risk of cracking at the welding points. The structure of the bonding layer 5, thicker in the middle and thinner on both sides, further enhances this stress buffering effect, ensuring that the connection maintains a stable conductive path even under long-term vibration or temperature cycling, preventing a sudden drop in module power due to connection failure.

[0031] The bonding layer 50 serves as the connection carrier between the interconnect strip 20 and the busbar. The low resistivity of the conductive cladding 202 and the substrate 301 significantly reduces the contact resistance and body resistance of the current in the interconnect strip 20, bonding layer 50, and busbar 30, preventing overheating losses caused by localized current accumulation. While the conductive core 201, as the main body of the interconnect strip 20, has a slightly higher resistivity due to the second conductive material, its overall resistance can be controlled within a reasonable range through thickness design. Furthermore, the low cost of aluminum reduces the material cost of the interconnect strip 20. Additionally, the low density of aluminum reduces the overall weight of the component.

[0032] The conductive coating 202 wraps around the conductive core 201. The conductive coating 202 plays a major role in transmitting current. The conductive coating 202 has a lower resistivity, which reduces the resistance when current is transmitted through the contact surface or surface, thereby improving the power of the component. As the main body of the conductive structure, if the conductive core 201 is made entirely of low-resistivity materials, such as pure copper, the cost would be high. However, by covering the surface with only a layer of low-resistivity conductive coating 202, the conductivity of key parts can be guaranteed, while the overall cost can be controlled through the conductive core 201.

[0033] Choosing an aluminum-copper alloy for interconnect strip 20 not only saves on material costs, but also reduces transportation and storage costs due to aluminum's lightweight properties. Furthermore, no additional process parameter adjustments are required during welding, minimizing equipment modification or process integration costs. In downstream applications, although the resistance of the copper-aluminum alloy interconnect strip 20 is slightly higher than that of the pure copper interconnect strip 20, the reduction in module conversion efficiency, achieved through adjustments to the core thickness and subsequent fine-tuning of the interconnect strip's cross-section, is far less than the increase in value resulting from the cost reduction.

[0034] In summary, the use of copper-clad aluminum cores, followed by interconnect strips 20 wrapped with a first welding layer 203 composed of tin-lead alloy, in actual production can significantly reduce material costs by leveraging the low-cost characteristics of aluminum cores, while ensuring the conductivity of interconnect strips 20 by utilizing the advantages of copper cladding. By welding the first welding layer 203 to the second welding layer 302, a balance between cost reduction and performance stability is achieved. This provides a practical solution for photovoltaic module manufacturers to improve profit margins and enhance market competitiveness, while also helping downstream photovoltaic projects reduce initial investment and accelerate the large-scale popularization of the photovoltaic industry.

[0035] Optionally, refer to Figure 3 , Figure 4 Along the third direction Z, the thickness d of the middle region of the conductive core 201 is less than the thickness d of the two side regions; the thickness c of the middle region of the conductive coating 202 is greater than the thickness c of the two side regions.

[0036] It should be noted that the middle region of the conductive core 201 refers to the portion located at the center of the conductive core 201 along the second direction Y. The two side regions of the conductive core 201 refer to the portions located at the two sides of the conductive core 201 along the second direction Y.

[0037] For example, along the second direction Y, the conductive core 201 can be divided into three parts: the middle part is the central region of the conductive core 201, and the parts on both sides are the two side regions of the conductive core 201. Alternatively, if the length of the conductive core along the second direction Y is S, the central region of the conductive core 201 refers to the part along the second direction Y near the center of the conductive core 201, and the length of the central region of the conductive core 201 along the second direction Y is 0.3*S. Understandably, the sum of the length of the conductive core 201 on one side of the center position (0.15*S) and the length on the other side of the center position (0.15*S) constitutes the central region of the conductive core 201. The conductive core 201 on both sides of the central region of the conductive core 201 are the two side regions of the conductive core 201, and the lengths of the two side regions of the conductive core 201 are 0.35*S each.

[0038] Of course, the above are only individual examples of the specific division of the middle and side regions of the conductive core 201, and are not intended to limit this application. In practical applications, those skilled in the art can also divide the middle and side regions of the conductive core 201 as needed.

[0039] In this application, the thickness d of the conductive core 201 and the thickness c of the conductive coating 202 can refer to the minimum thickness or the average thickness.

[0040] It should be noted that the middle region of the conductive coating 201 refers to the portion of the conductive coating 202 that covers the middle region of the conductive core 201 along the second direction Y in the cross-sectional view. The two side regions of the conductive coating 202 refer to the portions of the conductive coating 202 that cover the two side regions of the conductive core 201 along the second direction Y in the cross-section. It can be understood that any portion of the conductive coating 202 that covers the middle region of the conductive core 201 can be considered the middle region of the conductive coating 202, and any portion of the conductive coating 202 that covers the two side regions of the conductive core 201 can be considered the two side regions of the conductive coating 202.

[0041] like Figures 2 to 3 As shown, the conductive core 201 has a first side 2011 and a second side 2022 along the second direction Y. The portion of the conductive coating covering the first side 2011 and the second side 2022 is a first peripheral region and a second peripheral region. The thickness c of the first peripheral region and the second peripheral region of the conductive coating 202 is greater than or equal to the thickness c of the middle region of the conductive coating 202, and / or, the thickness c of the first peripheral region and the second peripheral region of the conductive coating 202 is greater than or equal to the thickness c of the two side regions of the conductive coating 202.

[0042] The conductive core 201 is a component for current transmission. Along the third direction Z, the thickness d of the middle region of the conductive core 201 is smaller than the thickness d of the two side regions. In other words, the thickness of the conductive core 201 gradually increases from the middle to the sides. This design allows the middle region of the conductive core 201 to maintain the basic conductive cross-sectional area while further increasing the cross-sectional area by thickening the sides. When the current is transmitted within the interconnecting strip 20, the current density in this region is reduced, reducing resistance loss and Joule heat loss caused by current concentration. This makes the transmission efficiency of the current along the conductive core 201 from the middle to the sides higher.

[0043] Since the thickness of the conductive core 201 gradually increases from the middle to both sides along the third direction Z, and the thickness of the conductive cladding 202 gradually decreases from the middle to both sides, this design can precisely match the position during welding and ensure that the middle area of ​​the cladding retains sufficient thickness to achieve a firm weld. In addition, the thinning of the cladding on both sides can reduce the coverage of the grid line edge of the cell 10, and avoid the welding pressure concentration caused by excessive cladding thickness.

[0044] Along the Z-direction, the thickness of the conductive core 201 gradually increases from the center to both sides, while the thickness of the conductive cladding 202 gradually decreases from the center to both sides. This ensures the basic conductivity on both sides of the conductive cladding 202, while the increased thickness in the center of the conductive core 201 further improves conductivity, reduces resistance loss, and increases module power. The conductive cladding 202 wraps around the conductive core 201, and the change in thickness along the Z-direction allows for a tighter fit without local gaps, resulting in a smoother overall appearance of the interconnect strip 20, facilitating production, transportation, and subsequent welding. Furthermore, the core only thickens on both sides where current is concentrated, avoiding material waste caused by overall thickening; the conductive cladding 202 retains sufficient thickness only in the critical welding area in the center, while the thinning on both sides reduces the amount of high-cost cladding material used, further lowering the cost of the interconnect strip 20 and the photovoltaic module.

[0045] Optionally, refer to Figure 3 The thickness c of the conductive cladding 202 and the thickness d of the conductive core 201 satisfy the following condition: 0.1 ≤ c / d ≤ 0.17; and / or, the thickness c of the conductive cladding 202 satisfies: 10 μm ≤ c ≤ 50 μm; and / or, the thickness d of the conductive core 201 satisfies: 100 μm ≤ d ≤ 300 μm.

[0046] In one embodiment, along the third direction Z, the thickness of the conductive core 201 gradually increases from the middle to both sides, while the thickness of the conductive cladding 202 gradually decreases from the middle to both sides. Since the thickness of the conductive core 201 increases as the thickness of the conductive cladding 202 decreases, when c / d ≥ 0.1, the cladding thickness is sufficient to completely cover the core surface and form a uniform welding layer, avoiding core exposure and incomplete or ineffective welding due to an excessively thin conductive cladding 202. When c / d ≤ 0.17, the conductive cladding 202 thickness is not excessive, avoiding material waste.

[0047] When the c / d ratio is controlled within the range of 0.1 to 0.17, the thickness of the conductive coating 202 is moderate. A c / d ratio of ≤0.17 can strictly control the amount of high-cost coating material used. At the same time, a c / d ratio of ≥0.1 avoids the need for secondary plating due to the conductive coating 202 being too thin, reducing rework costs and process complexity, and significantly improving economic efficiency. In addition, when the c / d ratio is controlled within the range of 0.1 to 0.17, it avoids core exposure and problems such as missing solder or poor soldering during welding, thus improving current transmission efficiency. The conductive cladding 202 serves both to transmit current and to protect the conductive core 201. The thickness c of the conductive cladding 202 must satisfy 10μm≤c≤50 to adhere to the surface of the conductive core 201 without easily developing defects such as wrinkles or peeling. It will not break due to being too thin, nor will it fail to adhere tightly to the conductive core due to being too thick. The conductive core 201 must provide support. The thickness d of the conductive core 201 must satisfy 10μm≤c≤50 to prevent bending or breaking during welding, and it will not increase transportation and installation costs due to being too thick.

[0048] Optionally, refer to Figure 2 The thickness a of the substrate 301 of the busbar 30 and the thickness c of the conductive coating 202 satisfy the following condition: 7 ≤ a / c ≤ 10.

[0049] Busbar 30 needs to collect the current from multiple battery strings 40, and the current value is much higher than that of a single interconnecting bar 20, requiring a stronger current-carrying capacity; while the conductive coating 202 is only responsible for the local conductivity between a single interconnecting bar 20 and the battery cell 10 and busbar 30. Busbar 30 has two forms. One type of busbar 30 has a uniform thickness of substrate 301 with a thickness of 'a', while the other type of busbar 30 can be designed based on the thickness of the conductive coating 202, with the thickness of substrate 301 of the busbar 30 being 'a' but exhibiting a gradient design based on the thickness of the conductive coating 202. Since the thickness of the conductive cladding 202 changes with its position, c is not a fixed value. When the thickness of the conductive cladding 202 changes, the ratio between the thickness c of the conductive cladding 202 and the thickness a of the substrate 301 of the busbar 30 also changes. When a / c is in the range of 7 to 10, the thickness of the substrate 301 of the busbar 30 is significantly greater than that of the conductive cladding 202. Its cross-sectional area and current carrying capacity can match the requirements of multiple current collection. The busbar 30 itself avoids local overheating due to current overload, and also avoids resistance redundancy caused by excessive thickness of the busbar 30. This ensures that there is no bottleneck in the transmission of current in the interconnecting strip 20 and the busbar 30, reduces overall power loss, improves current transmission efficiency, and steadily improves the component conversion efficiency.

[0050] Typically, improving module power by optimizing the cross-sectional area of ​​the busbar 30 can be achieved by optimizing the width and thickness of the busbar. However, increasing the width of the busbar 30 involves several issues: for non-hidden busbars, increasing the width of the edge busbars raises concerns about creepage distance at the module edge; increasing the width of the middle busbars raises concerns about the distance between the busbar and the non-standard solder strip; the busbar pressing against the cell can cause microcracks in the cell; and it also involves cell rearrangement issues. For hidden busbars, increasing the width raises concerns about the design of the cell edge PADs, insulation of the non-standard grid, and redesign of the size and position of the insulation layer.

[0051] Typically, when improving component power by optimizing the cross-section of the interconnect strip 20, this can be achieved by optimizing the width and thickness of the interconnect strip 20. However, increasing the width of the interconnect strip may lead to shading issues, problems with the interconnect strip's design in relation to the insulating adhesive and PAD points, and compatibility issues with existing equipment and designs.

[0052] Therefore, based on the compatibility of existing equipment and designs, as well as cost considerations, this application improves component power by optimizing the thickness of busbar 30 and interconnect bar 20.

[0053] Optionally, refer to Figure 2 Along the third direction Z, the thickness of the substrate of busbar 30 is a, 0.1mm≤a≤0.35, and the total thickness of the conductive core 201 and conductive coating of interconnecting strip 20 is b, 0.1mm≤b≤0.3mm, and a and b satisfy: a / b≤1.16.

[0054] Along the third direction Z, the thickness of busbar 30 is 'a', where 0.1mm ≤ a ≤ 0.35. The total thickness of the conductive core 201 and conductive coating of interconnecting strip 20 is 'b', where 0.1mm ≤ b ≤ 0.3, and simultaneously a / b ≤ 1.16. Since the core function of busbar 30 is to collect and discharge the current from each battery string 40, when the widths of interconnecting strip 20 and busbar 30 are constant, if the substrate 301 in busbar 30 is too thick (i.e., a is much greater than b), the current flowing from the thinner interconnecting strip 20 to the thicker busbar 30 is prone to local current accumulation at the interface, increasing additional resistance and Joule heat loss. However, when a / b ≤ 1.16, the thicknesses are matched, and the current can be transmitted along a smooth path at the interface where interconnecting strip 20 and busbar are welded, reducing resistance and improving the current collection efficiency of busbar 30. This further reduces the overall power loss of the module and indirectly promotes improved conversion efficiency.

[0055] Furthermore, photovoltaic modules, exposed to the outdoors for extended periods, experience thermal expansion and contraction due to diurnal temperature variations and solar heating. If the busbar 30 and interconnect bar 20 have significantly different thicknesses, their thermal expansion amounts differ, with the thicker component experiencing greater expansion and contraction. This can exert tensile or compressive stress on the thinner component, potentially leading to cracking at welded joints, deformation of the interconnect bar 20, and even microcracks in the solar cell 10 over long-term cycles. However, when a / b ≤ 1.16, their thermal expansion amounts are similar, and the stresses in the thickness direction cancel each other out, resulting in no significant unidirectional stress concentration and ensuring the long-term stability of the photovoltaic module structure.

[0056] Furthermore, when a / b ≤ 1.16, the thickness of the back of the module is uniform with no obvious protrusions, improving the fit with the support and reducing local protrusions in the thickness direction of the module, thus enhancing installation adaptability and aesthetics. While improving installation efficiency, the uniform appearance also reduces the risk of dust and water accumulation, further ensuring the long-term stability of the photovoltaic module structure.

[0057] Optionally, the thickness of the middle region of the bonding layer 50 along the third direction Z is greater than the thickness of the two side regions along the third direction Z.

[0058] It is understood that the definitions of the middle and side regions of the bonding layer in this application can be referred to the definitions of the middle and side regions of the conductive core 201 mentioned above, and will not be repeated here.

[0059] In one embodiment, the bonding layer 50 is formed by welding a first welding layer 203 and a second welding layer 302 of tin-lead alloy. Tin-lead alloy has a low melting point and is easy to melt during the welding process, fully wetting the surfaces of the copper conductive cladding 202 and the copper substrate 301 to form a tight metallurgical bond, avoiding problems such as incomplete welding or false welding. At the same time, tin-lead alloy has good ductility after cooling, which can adapt to the thermal expansion and contraction stress caused by the temperature difference between day and night when the photovoltaic module is used outdoors, reducing the risk of cracking at the welding point. The structure of the bonding layer 50, which is thick in the middle and thin on both sides along the third direction Z, further enhances this stress buffering effect, so that the connection part can maintain a stable conductive path even under long-term vibration or temperature cycling, avoiding a sudden drop in module power due to connection failure.

[0060] Optionally, refer to Figure 2 Along the third direction Z, the thickness of the middle region of the bonding layer 50 is greater than the thickness of the two side regions. The thickness of the bonding layer 50 is D, the thickness of the first welding layer 203 is D1, and the thickness of the second welding layer 302 is D2, where D > D1 or D > D2.

[0061] The bonding layer 50 has the greatest thickness at its center, with a thickness of D. The first welding layer 203 also has the greatest thickness at its center, with a thickness of D1. The second welding layer 302 has a thickness of D2. D > D1 or D > D2 means that during welding, the solder in the first welding layer 203 and the second welding layer 302 fully melts, not only filling the contact gap between the interconnect strip 20 and the busbar 30, but also forming solder accumulation, making the bonding layer 50 thicker. The thicker bonding layer 50 can significantly increase the connection contact area between the interconnect strip 20 and the busbar 30. Compared to the thin connecting layer that just fills the gap when D ≤ D1 or D ≤ D2, the thicker bonding layer 50 can expand the stress area of ​​the connection part, thereby dispersing the mechanical stress on the interconnect strip and busbar during assembly, transportation, or outdoor use, avoiding the peeling or cracking of the weld point caused by local stress concentration, and reducing the risk of early failure of the component due to mechanical damage.

[0062] A thicker bonding layer D>D1 or D>D2 can reduce defects caused by insufficient solder during the welding process. The design of D>D1 or D>D2 can ensure that a continuous and dense conductive path is formed throughout the bonding layer through solder redundancy, avoid local high resistance caused by solder defects, further reduce ohmic loss during current transmission, and ensure stable component output power.

[0063] Optionally, refer to Figure 3 , Figure 4 The first weld layer 203 is oriented along the third direction Z, and the thickness of the middle region is greater than the thickness of the two side regions.

[0064] When photovoltaic modules are used outdoors, the temperature difference between day and night causes deformation of the interconnect strip 20 and the busbar 30 due to the difference in their coefficients of thermal expansion, with more obvious deformation and stress concentration at the edges. The first welding layer 203 is thicker in the middle and thinner on both sides. The thicker solder in the middle provides sufficient structural support to resist slight thermal stress in the middle area; the thinner solder on both sides is more flexible and can flexibly expand and contract with the deformation of the component edges, avoiding cracking due to excessive thickness and rigidity of the solder. At the same time, if the module is subjected to slight impact during transportation or installation, the thinner solder on both sides can also absorb the impact energy, reducing the risk of damage to the welding points.

[0065] Optionally, along the second direction Y, the width of the bonding layer 50 is greater than the width of the interconnect strip 20.

[0066] The width of the contact between the interconnect strip 20 and the bus strip 30 directly determines the cross-sectional area of ​​the conductive path. When the width of the bonding layer 50 is greater than the width of the interconnect strip 20, the current transmitted by the interconnect strip 30 can be dispersed to the bus strip 30 through the wider bonding layer 50.

[0067] The portion of the bonding layer 50 that extends beyond the width of the interconnect strip 20 is equivalent to forming additional welding support areas on both sides of the interconnect strip, thereby expanding the physical connection area between the interconnect strip 20 and the busbar 30. The larger connection area can disperse various stresses borne by the photovoltaic module during use and transportation, improving the structural stability and service life of the photovoltaic module.

[0068] In addition, this design can improve the fault tolerance of the welding process. When the width of the bonding layer 50 is greater than the width of the interconnect strip 20, even if there is a slight alignment deviation during the welding process, the interconnect strip 20 can still be completely covered by the bonding layer, ensuring that there are no defects such as false welding or missing welding in the welding area, improving the component manufacturing efficiency and indirectly reducing production costs.

[0069] Optionally, the first welding layer 203 and the second welding layer 302 are made of the same material.

[0070] When the first welding layer 203 and the second welding layer 302 are made of the same material and have the same coefficient of thermal expansion, the molten solder can form a continuous and uniform bonding layer 50 when the busbar 30 and the interconnecting strip 20 are welded. Under long-term vibration and thermal cycling of the photovoltaic module, the welded parts are less prone to cracking or detachment, fundamentally avoiding problems such as open circuits in the battery string 40 caused by connection failure between the busbar 30 and the interconnecting strip 20.

[0071] In one embodiment, both the first welding layer 203 and the second welding layer 302 are made of tin-lead alloy. Tin-lead alloy has a low melting point, allowing it to easily melt and fully wet the surfaces of the copper conductive cladding 202 and the copper substrate 301 during welding. When the materials of the first welding layer 203 and the second welding layer 302 are identical, the tin-lead alloy melts to form a uniformly mixed solder. After cooling, it forms a continuous bonding layer without significant interface delamination or defects, ensuring a stable metallurgical bond between the interconnect 20 and the busbar 30, reducing the risk of conductivity interruption due to welding interface failure. Furthermore, the bonding layer 50 formed after the tin-lead alloy melts can absorb external stress through its own deformation, improving the lifespan of the photovoltaic module.

[0072] Optionally, refer to Figure 5 and Figure 6 The busbar 30 is disposed between the interconnecting bar 20 and the solar cell 10; the busbar 30 is provided with multiple conductive parts 303 and insulating parts 304, which are spaced apart, and the interconnecting bar 20 is welded to the conductive parts 303. This design further increases the effective power generation area of ​​the module and improves the module power.

[0073] In this implementation, the interconnecting strip 20, the busbar 30, and the battery cell 10 are arranged sequentially. Conductive portions 303 and insulating portions 304 are spaced apart on the busbar 30, and an insulating layer 60 is provided between the busbar 30 and the battery cell 10 to prevent short circuits or other accidents caused by the connection of the grid lines on the busbar 30 and the battery cell 10. This design can precisely achieve zoned conductivity and isolation insulation, especially in back-contact batteries, avoiding the risk of electrode short circuits.

[0074] In back-contact batteries, both positive and negative electrodes are present on the back side. If the busbar 30 is conductive as a whole, it can easily lead to a direct connection between the positive and negative electrodes, forming a short circuit. However, in the embodiment provided in this application, the conductive part 303 on the busbar 30 is only welded to the electrode of the single-polarity battery cell 10, and collects current of the same polarity through the interconnecting strip 20. It is also isolated by the insulating part 304 and does not come into contact with any electrode. This structure can strictly distinguish the positive and negative current channels, avoid short circuits between electrodes of different polarities through the busbar 30, and ensure that the power generation advantage of the back-contact battery without front-side obstruction is not negated by the short-circuit problem.

[0075] In this implementation, the busbar 30 should be positioned to avoid the PAD points (pads) on the battery cell 10 to prevent the busbar 30 from being raised by the PAD points, resulting in greater stress at the connection and potential connection failures due to breakage during use.

[0076] Optionally, refer to Figure 7 and Figure 8 The photovoltaic module also includes an insulating layer 60; the insulating layer 60 is disposed between the busbar 30 and the interconnecting bar 20, and the interconnecting bar 20 is disposed between the insulating layer 60 and the solar cell 10; the insulating layer 60 has a plurality of welding holes 601, and the busbar 30 is welded to the interconnecting bar 20 through the welding holes 601.

[0077] The insulating layer 60 constructs a precise electrical isolation barrier, completely eliminating the risk of unexpected short circuits between the busbar 30 and the interconnecting strip 20. In photovoltaic modules, the busbar 30 needs to collect current from multiple cell strings 40, while the interconnecting strip 20 is responsible for the current conduction of a single cell string 10. If the two are in direct contact, insulation failure can easily lead to the connection of different current loops, causing a partial short circuit. The insulating layer 60 completely isolates the non-welded areas of the busbar 30 and the interconnecting strip 20, retaining the necessary conductive path between the busbar 30 and the interconnecting strip 20 only through the pre-set welding holes 601. Furthermore, the position and size of the welding holes 601 are strictly matched to the welding requirements, preventing contact between the non-welded parts of the busbar 30 and the interconnecting strip 20 due to hole misalignment or excessive size.

[0078] The supporting function of the insulating layer 60 enables the busbar 30 and the interconnecting strip 20 to achieve precise point-to-point welding through the welding holes 601, avoiding poor adhesion of the welding surfaces due to lack of support. During welding, the solder can be concentrated and filled in the contact area between the busbar 30 and the interconnecting strip 20 through the welding holes 601, forming a uniform and dense intermetallic compound layer. Furthermore, the welding holes 601 on the insulating layer 60 can fix the position of the welding node, reduce the increase in resistance caused by stress deformation of the welding surface, and ensure stable current transmission efficiency.

[0079] In this implementation, the busbar 30 should be positioned to avoid the PAD points on the battery cell 10. This prevents the busbar 30 from being raised by the PAD points, resulting in greater stress at the connection point and potential connection failure due to breakage during use. Optionally, refer to... Figure 1 The busbar 30 includes an edge busbar 305 and a middle busbar 306; the edge busbar 305 is disposed at both ends of the photovoltaic module along the first direction X, and the middle busbar 306 is disposed between the two edge busbars 305; along the first direction X, the width of the middle busbar 306 is e, and the width of the edge busbar 305 is f, (ef) ≥ 0.5 mm.

[0080] Along the first direction X, the central busbar 306 needs to collect the current from multiple battery strings 40 on both sides, while the edge busbar 305 only needs to collect the current from 1-2 battery strings near the edge of the module. The current load of the central busbar 306 is typically at least 3-5 times that of the edge busbar 305. Given the same thickness, (ef) ≥ 0.5mm means that the central busbar 306 has a larger cross-sectional area, which increases its current carrying capacity. This effectively disperses the Joule heat generated by high current, preventing the metal from softening and resistance from increasing due to excessive temperature. It also eliminates the risk of the busbar 30 melting or experiencing performance degradation due to overload, ensuring long-term stable power generation of the module.

[0081] Furthermore, this design optimizes material costs while ensuring performance, achieving a balance between functionality and cost. Since busbars 30 are mostly made of high-purity copper, cost is positively correlated with width; with the thickness and length remaining constant, a wider busbar increases cost. The central busbar 306, needing to carry high current, maintains its performance by increasing its width while keeping the thickness constant. However, the edge busbars 305 have lower current loads and do not require excessive width, allowing for a slight reduction in width. This 0.5mm width difference reduces the amount of copper used in the edge busbars 305. This significantly reduces production costs without sacrificing component performance, enhancing the product's market competitiveness.

[0082] With the cell layout unchanged, the width of the intermediate busbar 306 is greater than the width of the edge busbar 305. This results in the distance between the PAD point on the cell 10 adjacent to the edge busbar 305 and the edge of the edge busbar 305 being greater than the distance between the PAD point on the cell 10 adjacent to the intermediate busbar 306 and the edge of the intermediate busbar 306. The angle between the solder ribbon surface on the intermediate busbar 306 and the solder ribbon surface on the cell 10 is A1; the angle between the solder ribbon surface on the edge busbar 305 and the solder ribbon surface on the cell 10 is A2; A1>A2. Because the height of the intermediate busbar 306 and the edge busbar 305 along the third direction Z remains unchanged, the angle increases as the distance decreases. The height difference between the surface of the interconnect strip 20 and the surface of the busbar 30 on the cell 10 creates an angle, which poses a challenge to the welding process. Because the conductive core of interconnect strip 20 is made of softer aluminum, it is more flexible and better suited for connecting battery strings to busbar 30. This overcomes the welding angle issues associated with hidden busbar designs and improves welding stability. Optionally, refer to... Figure 9 The battery cell 10 includes a first grid line 70 and a second grid line 80. The interconnecting strip 20 includes a first interconnecting strip 204 and a second interconnecting strip 205. The first grid line 70 and the second grid line 80 have opposite polarities and are spaced apart. The first interconnecting strip 204 is welded to the first grid line 70, and the second interconnecting strip 205 is welded to the second grid line 80. A first insulating portion 2041 is provided at the contact position between the first interconnecting strip 204 and the second grid line 80, and a second insulating portion 2051 is provided at the contact position between the second interconnecting strip 205 and the first grid line 70. An insulating layer 60 is provided on the first insulating portion 2041 and the second insulating portion 2051. Along the second direction Y, the width of the first insulating portion 2041 and the second insulating portion 2051 is greater than the width of the interconnecting strip 20.

[0083] The first grid line 70 and the second grid line 80 of the battery cell 10 have opposite polarities and are arranged at intervals. Since the first interconnecting strip 204 is welded to the first grid line 70 and the second interconnecting strip 205 is welded to the second grid line 80, if the first interconnecting strip 204 and the second grid line 80 are in direct contact, or if the second interconnecting strip 205 and the first grid line 70 are in direct contact, a short circuit of opposite polarities will be formed, causing the battery cell 10 to fail. The first insulating part 2041 covers the contact area between the first interconnecting strip 204 and the second grid line 80, and the second insulating part 2051 covers the contact area between the second interconnecting strip 205 and the first grid line 70. The width of the insulating part along the second direction Y is greater than the width of the interconnecting strip 20. For example, when the width of the interconnecting strip 20 is 0.6mm, the width of the insulating part is 2-3mm. This design can cover the positional deviation of the interconnecting strip 20 caused by installation offset and thermal expansion and contraction, and avoid the insulation part being unable to cover the contact area due to the displacement of the interconnecting strip 20. This ensures that the positive and negative circuits of the battery cell 10 are completely isolated and that the current is transmitted only along the grid line to the corresponding interconnecting strip 20 via a preset path.

[0084] Optionally, refer to Figure 3 , Figure 4 Along the third direction Z, the cross section of interconnecting strip 20 is rectangular, rounded rectangle or elliptical.

[0085] In one embodiment, the interconnect strip 20 has a rectangular cross-section with flat and fixed-area upper and lower contact surfaces. The contact with the cell pads or the conductive adhesive of the busbar is a surface contact, which maximizes the contact area, reduces contact resistance, and reduces local heat loss during current transmission. This is especially suitable for high-power modules with high conductivity requirements. At the same time, the flat contact surface facilitates precise pressure application and temperature control by the welding equipment. During welding, heat can be evenly transferred to the contact area, avoiding poor soldering or over-soldering caused by uneven contact. In addition, the rectangular structure has high rigidity and is not easily deformed during the module lamination and encapsulation process. It can maintain a stable conductive connection state for a long time and ensure the long-term power generation performance of the module.

[0086] In another embodiment, the cross-section of the interconnect strip 20 is a rounded rectangle. The rounded corner design can eliminate the sharp edges and corners of the rectangular cross-section. On the one hand, during the production process, it can prevent the sharp edges and corners from scratching the surface of the cell or the encapsulation material when the interconnect strip is assembled with the cell and busbar, reducing the risk of microcracks in the cell and water ingress caused by damage to the encapsulation layer. On the other hand, during long-term outdoor use of the module, the stress distribution at the rounded corners is more uniform, which can reduce the local stress concentration caused by temperature cycling, prevent the solder joint from falling off or the wire from breaking due to stress tension at the connection between the interconnect strip and the pad, extend the service life of the interconnect strip, and improve the fatigue resistance of the module.

[0087] The interconnecting strip 20 with a rectangular or rounded rectangular cross-section can increase the contact width with the grid lines of the battery cell 10 when welded with the long side, under the same material usage. This makes the current transmission path smoother and more dispersed when it is introduced from the grid lines of the battery cell 10 into the interconnecting strip 20, avoiding current concentration caused by insufficient contact width.

[0088] In addition, the mechanical stress resistance of the interconnect strip 20 can be improved. The rectangular or rounded rectangular sides allow the interconnect strip 20 to better fit the slight undulations on the surface of the cell 10 during lamination, reducing the deformation of the interconnect strip 20 caused by lamination pressure, and significantly improving the long-term reliability of the photovoltaic module.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A photovoltaic module, characterized in that, The photovoltaic module includes: multiple solar cells (10), interconnect strips (20) and busbars (30); The plurality of said solar cells (10) are arranged in an array along a first direction (X) and a second direction (Y); the photovoltaic module has a third direction (Z) that is perpendicular to the plane formed by the first direction (X) and the second direction (Y); Along the first direction (X), the interconnecting strip (20) welds a plurality of the battery cells (10) to form a battery string (40), and along the second direction (Y), the busbar (30) welds the battery string (40) to form a battery pack; The interconnecting strip (20) includes a conductive core (201), a conductive coating (202), and a first welding layer (203). The conductive coating (202) is disposed outside the conductive core (201) and wraps around the conductive core (201). The first welding layer (203) is disposed outside the conductive coating (202) and wraps around the conductive coating (202). The busbar (30) includes a substrate (301) and a second welding layer (302), wherein the second welding layer (302) is disposed on the outside of the substrate (301); The first welding layer (203) and the second welding layer (302) are welded to form a bonding layer (50), and the interconnecting strip (20) and the busbar (30) are electrically connected through the bonding layer (50); The conductive coating (202) and the substrate (301) are made of a first conductive material, and the conductive core (201) is made of a second conductive material. The resistivity of the first conductive material is less than that of the second conductive material.

2. The photovoltaic module according to claim 1, characterized in that, Along the third direction (Z), the thickness d of the middle region of the conductive core (201) is less than the thickness d of the two side regions; and / or, The thickness c of the middle region of the conductive coating (202) is greater than the thickness c of the two side regions.

3. The photovoltaic module according to claim 2, characterized in that, Along the third direction (Z), the thickness c of the conductive cladding (202) and the thickness d of the conductive core (201) satisfy: 0.1 ≤ c / d ≤ 0.17; and / or, The thickness c of the conductive coating (202) satisfies: 10μm≤c≤50μm; and / or, The thickness d of the conductive core (201) satisfies: 100μm≤d≤300μm.

4. The photovoltaic module according to claim 3, characterized in that, Along the third direction (Z), the thickness a of the substrate (301) of the busbar (30) and the thickness c of the conductive coating (202) satisfy: 7≤a / c≤10.

5. The photovoltaic module according to claim 1, characterized in that, Along the third direction (Z), the thickness of the substrate (301) of the busbar (30) is a, 0.1mm≤a≤0.35mm, and the thickness of the interconnecting strip (20) is b, 0.1mm≤b≤0.3mm, and a and b satisfy: a / b≤1.

16.

6. The photovoltaic module according to claim 1, characterized in that, The thickness of the middle region of the bonding layer (50) along the third direction (Z) is greater than the thickness of the two side regions along the third direction (Z).

7. The photovoltaic module according to claim 1, characterized in that, Along the third direction (Z), the thickness of the middle region of the bonding layer (50) is greater than the thickness of the two side regions, and the thickness of the bonding layer (50) is D; The thickness of the middle region of the first weld layer (203) is greater than the thickness of the two side regions. The thickness of the first weld layer (203) is D1, and the thickness of the second weld layer (302) is D2, where D > D1 or D > D2.

8. The photovoltaic module according to claim 1, characterized in that, The thickness of the first weld layer (203) in the middle region along the third direction (Z) is greater than the thickness of the two side regions.

9. The photovoltaic module according to claim 1, characterized in that, Along the second direction (Y), the width of the bonding layer (50) is greater than the width of the interconnecting strip (20).

10. The photovoltaic module according to claim 1, characterized in that, The first welding layer (203) and the second welding layer (302) are made of the same material.

11. The photovoltaic module according to claim 1, characterized in that, The busbar (30) is disposed between the interconnecting bar (20) and the battery cell (10); The busbar (30) is provided with a plurality of conductive parts (303) and insulating parts (304), and the conductive parts (303) and the insulating parts (304) are arranged at intervals; The interconnecting strip (20) is welded to the conductive part (303).

12. The photovoltaic module according to claim 1, characterized in that, The busbar (30) is disposed on the interconnect bar (20), and the interconnect bar is located between the busbar (30) and the battery cell (10); An insulating layer (60) is further provided between the busbar (30) and the interconnecting bar (20). The insulating layer (60) has a plurality of welding holes (601), and the busbar (30) is welded to the interconnecting strip (20) through the welding holes (601).

13. The photovoltaic module according to claim 1, characterized in that, The busbar (30) includes an edge busbar (305) and a middle busbar (306); The edge busbars (305) are disposed at both ends of the photovoltaic module along the first direction (X), and the middle busbar (306) is disposed between the two edge busbars (305); Along the first direction (X), the width of the intermediate busbar (306) is e, and the width of the edge busbar (305) is f, (ef) ≥ 0.5 mm.

14. The photovoltaic module according to claim 12, characterized in that, The battery cell (10) includes a first grid line (70) and a second grid line (80), and the interconnecting strip (20) includes a first interconnecting strip (204) and a second interconnecting strip (205). The first gate line (70) and the second gate line (80) have opposite polarities. The first gate line (70) and the second gate line (80) are spaced apart. The first interconnecting strip (204) is welded to the first gate line (70), and the second interconnecting strip (205) is welded to the second gate line (80). The first interconnecting strip (204) is provided with a first insulating part (2041) at the position where it contacts the second grid line (80), and the second interconnecting strip (205) is provided with a second insulating part (2051) at the position where it contacts the first grid line (70). Insulating adhesive is provided on the first insulating part (2041) and the second insulating part (2051). Along the second direction (Y), the widths of the first insulating portion (2041) and the second insulating portion (2051) are greater than the width of the interconnecting strip (20).

15. The photovoltaic module according to claim 1, characterized in that, Along the third direction (Z), the cross section of the interconnecting strip (20) is rectangular, rounded rectangle or elliptical.

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