Bus bar and photovoltaic module

Abstract

The utility model provides a busbar and a photovoltaic module, which relate to the field of photovoltaic technology, in order to solve the technical problem of poor high-temperature reliability of the solder joints between the busbar and the interconnection bar. The busbar includes a substrate and a first solder layer formed on the substrate; the first solder layer has grooves formed on the top surface and one side surface for accommodating the welding section of the interconnection bar, and the first solder layer has a target thickness at the bottom of the groove; when the target thickness is zero, the bottom of the groove is used for welding with the welding section through the second solder layer; when the target thickness is greater than zero and less than or equal to the preset thickness, the first solder layer is located at the bottom of the groove for welding the substrate with the welding section; at least part of the first solder layer is used to fill the groove and cover the welding section. When the busbar and the interconnection bar of the utility model are welded, a full IMC structure can be formed, thereby improving the high-temperature reliability of the solder joint.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a bus bar and a photovoltaic component. Background Art

[0002] The statements in this section merely provide background technology related to the present invention and do not necessarily constitute prior art.

[0003] Some photovoltaic cells are not resistant to high temperatures, so low-temperature interconnection technology is needed to weld the interconnection bars to the bus bars. In the related technology, the connection between the bus bars is mainly achieved by welding the interconnection bars wrapped with a solder layer on the surface of the bus bar. When the external temperature is too high, for example, the lamination temperature of the photovoltaic cell lamination process may be higher than the melting point of the solder joint, and the above solder joints will be at risk of remelting and falling off. Utility Model Content

[0004] The utility model aims to provide a bus bar and a photovoltaic module to solve the technical problem that the welding points between the bus bar and the interconnection bar are not resistant to high temperature.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] In a first aspect, the utility model provides a busbar, comprising a substrate and a first solder layer formed on the substrate;

[0007] The first solder layer has grooves formed on the top surface and one side surface for accommodating the welding section of the interconnection strip, and the first solder layer has a target thickness at the bottom of the groove;

[0008] When the target thickness is zero, the bottom of the groove is used for welding with the welding section through a second solder layer;

[0009] When the target thickness is greater than zero and less than or equal to a preset thickness, the first solder layer is located at the bottom of the groove for welding the substrate and the welding section;

[0010] At least a portion of the first solder layer is used to fill the groove and cover the welding section.

[0011] According to at least one embodiment of the present invention, the preset thickness is 15 μm.

[0012] According to at least one embodiment of the present utility model, the ratio of the width of the groove to the diameter of the interconnection strip is in the range of 1.5 to 2; wherein,

[0013] The width direction of the groove is perpendicular to the extending direction of the interconnection strip.

[0014] According to at least one embodiment of the present invention, the depth of the groove is greater than the diameter of the interconnection strip; and / or,

[0015] The length of the groove is greater than half the width of the busbar; wherein,

[0016] The length direction of the groove and the width direction of the bus bar are both parallel to the extension direction of the interconnection bar.

[0017] According to at least one embodiment of the present utility model, the number of the grooves is multiple, and the multiple grooves are arranged along the length direction of the busbar;

[0018] In the length direction of the busbar, along the direction away from the groove, the thickness of the first solder layer decreases or remains constant; wherein,

[0019] The length direction of the bus bar is perpendicular to the extending direction of the interconnection bar.

[0020] In a second aspect, the utility model provides a photovoltaic assembly, comprising a bus bar and a plurality of interconnection bars, wherein the bus bar is the bus bar described in the first aspect, and the welding section of each interconnection bar is embedded in the corresponding groove;

[0021] When the target thickness is zero, the welding section is coated with the second solder layer, the thickness of the second solder layer is greater than 0 and less than or equal to the preset thickness, and the welding section is welded to the substrate through the second solder layer;

[0022] When the target thickness is greater than zero and less than or equal to the preset thickness, the welding section is welded to the substrate through the portion of the first solder layer located at the bottom of the groove.

[0023] According to at least one embodiment of the present invention, the busbar further includes a coating layer filled in the groove, the coating layer is formed by at least a portion of the first solder layer, and the coating layer covers the welding section and / or the second solder layer.

[0024] According to at least one embodiment of the present utility model, an intermetallic compound layer is formed between the welding section and a portion of the substrate located in the groove.

[0025] According to at least one embodiment of the present utility model, the welding section is a welding section made of copper, and the substrate is a substrate made of copper;

[0026] The first solder layer is made of a first tin-based alloy;

[0027] The intermetallic compound layer is a copper-tin intermetallic compound layer.

[0028] According to at least one embodiment of the present utility model, when the target thickness is zero, the second solder layer is made of a second tin-based alloy;

[0029] The intermetallic compound layer is a copper-tin intermetallic compound layer.

[0030] Among the one or more technical solutions provided in the exemplary embodiments of the present utility model, at least one of the following beneficial effects can be achieved.

[0031] The busbar of the exemplary embodiment of the utility model includes a substrate and a first solder layer formed on the substrate, and a groove is formed on the top surface and one side surface of the first solder layer. After the bottom of the groove is connected to the welding section of the interconnection bar by welding through the second solder or the first solder, at least part of the first solder layer can be melted and filled in the groove and coated on the welding section. Since the target thickness of the first solder layer at the bottom of the groove is zero or less than or equal to the preset thickness, compared with the prior art in which the welding section is directly wrapped on the solder layer of the busbar substrate, the spacing between the welding section and the busbar substrate is smaller. Therefore, when the welding section is welded to the busbar substrate, both the second solder and the first solder can form a complete intermetallic compound between the two, and the melting point of the intermetallic compound is higher than the melting point of the first solder, thereby reducing the risk of the solder joint between the interconnection bar and the busbar remelting and falling off due to high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings illustrate exemplary embodiments of the present invention and are used to explain the principles of the present invention together with the description thereof, wherein these drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification;

[0033] Figure 1 is a schematic diagram of an axonometric structure of a busbar according to an embodiment of the utility model;

[0034] Figure 2 It is a schematic diagram of the isometric structure of the busbar groove according to the embodiment of the utility model;

[0035] Figure 3 It is a schematic diagram of the isometric structure of the bus bar and the interconnection bar (before the coating layer is formed) according to an embodiment of the utility model;

[0036] Figure 4 It is a schematic diagram of the isometric structure of the bus bar and the interconnection bar (after forming the coating layer) according to the embodiment of the utility model;

[0037] Figure 5 is a schematic diagram of the welding mechanism of bus bars and interconnection bars according to an embodiment of the present utility model;

[0038] Figure 6It is a schematic diagram of the welding mechanism of bus bars and interconnection bars in the prior art;

[0039] Figure 7 is a schematic diagram of a busbar structure viewed from above according to an embodiment of the utility model;

[0040] Figure 8 This is a schematic diagram of the main structure of a bus bar (suitable for interconnection bars 0.26mm<d) according to an embodiment of the utility model;

[0041] Fig. 9 This is a schematic diagram of the main structure of a bus bar (suitable for interconnection bars 0.2 mm ≤ d ≤ 0.26 mm) according to an embodiment of the utility model;

[0042] Fig.10 It is a schematic diagram of the main structure of a bus bar (suitable for interconnection bars d<0.2mm) according to an embodiment of the utility model.

[0043] Figure numerals: 10, first solder layer; 11, top surface; 12, side surface; 13, cladding layer; 20, substrate; 30, groove; 31, groove bottom; 40, interconnection strip; 41, welding section; 50, intermetallic compound layer; 60, second solder layer. DETAILED DESCRIPTION

[0044] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] Before introducing the embodiments of the present invention, the following definitions are given for the terms involved in the embodiments of the present invention:

[0046] Intermetallic Compound (IMC), which is the product of interface reaction, is also a sign of the formation of a good solder joint.

[0047] Among various solder alloys, Sn is the main component and the main element involved in the formation of IMC. The remaining elements are mainly used to lower the melting point of the solder and suppress the growth of IMC. A small amount of Cu and Ni will also affect the structure of IMC. Under lead-containing process conditions, the IMC formed at the interface between tin-lead solder and Cu and Ni, only Sn in the solder participates in the formation of IMC, and the composition of IMC is fixed. Under lead-free process conditions, due to the large number of lead-free solders used, the composition and morphology of IMC are relatively complex. For example, when using SAC305 solder, the IMC formed at the interface between the solder and the Ni base is a double-layer ternary alloy layer of (Cu, Ni)6Sn5 and (Cu, Ni)3Sn4.

[0048] Intrinsic thin film heterojunction cells (HJT) have the advantages of short process flow and high conversion efficiency, but due to its high temperature resistance, HJT cells need to use low-temperature interconnection technology, in which the melting point of the solder joint between the interconnection bar and the bus bar is even lower than the lamination temperature. This is because in the prior art, the welding between the interconnection bar and the bus bar is usually achieved by wrapping the interconnection bar with a tin-lead layer on the surface of the bus bar.

[0049] Figure 6 Schematic diagram of the welding mechanism of busbars and interconnection bars in the prior art, such as Figure 6 As shown, the connection method of wrapping the interconnection bar with the tin-lead layer on the surface of the busbar is adopted. Since the full IMC structure cannot be formed, the melting point of the solder joint between the busbar and the interconnection bar is determined by the melting point of the tin-lead layer on the surface of the busbar and the solder on the surface of the interconnection bar. The melting point of the tin-lead layer on the surface of the busbar is 183°C. With the application of low-temperature interconnection technology, the melting point of the solder on the surface of the interconnection bar continues to decrease. In the lamination process of subsequent photovoltaic cell production, the lamination temperature may be higher than the melting point of the solder on the surface of the interconnection bar, causing the solder joint to remelt and fall off. Especially when HJT cells require lower low-temperature interconnection, the above solder joints are more likely to remelt, resulting in a reduction in contact area, an increase in resistance, and even an increase in the risk of the solder joint falling off completely.

[0050] In response to the above problems, an embodiment of the utility model provides a busbar, including a base and a first solder layer formed on the base; the first solder layer has grooves formed on the top surface and one side surface for accommodating the welding section of the interconnection bar, and the first solder layer has a target thickness at the bottom of the groove; when the target thickness is zero, the bottom of the groove is used for welding with the welding section through the second solder layer; when the target thickness is greater than zero and less than or equal to the preset thickness, the first solder layer is located at the bottom of the groove for welding the base and the welding section; at least a portion of the first solder layer is used to fill the groove and cover the welding section.

[0051] The busbar provided by the exemplary embodiment of the utility model is formed by opening a groove on the first solder layer of the substrate. When the welding section of the interconnection bar is placed in the groove, the distance between the welding section and the substrate is smaller than that of directly using the first solder layer to wrap the welding section. Then, the welding section, the substrate and the solder therebetween form a full IMC layer. The IMC layer has high-temperature stability, thereby improving the high-temperature resistance of the solder joint and reducing the risk of failure.

[0052] Figure 1 is a schematic diagram of an axonometric structure of a busbar according to an embodiment of the utility model; Figure 2 Schematic diagram of the isometric structure of the busbar groove according to the embodiment of the utility model. Figure 1 and Figure 2As shown, the busbar provided by the exemplary embodiment of the utility model includes a substrate 20 and a first solder layer 10 formed on the surface of the substrate 20. The first solder layer 10 is formed with a groove 30 having two openings on the top surface 11 and one side surface 12, wherein one opening is formed on the top surface 11 and the other opening is formed on one side surface 12, that is, the groove 30 is surrounded by three side walls and a groove bottom 31. The top surface 11 of the first solder layer 10 is the surface facing away from the substrate 20, and the first solder layer 10 has four side surfaces 12, and an opening is formed on one side surface 12 where the interconnection bar needs to be inserted.

[0053] Figure 3 It is a schematic diagram of the isometric structure of the bus bar and the interconnection bar (before the coating layer is formed) according to an embodiment of the utility model; Figure 5 Schematic diagram of the welding mechanism of busbars and interconnection bars according to an embodiment of the present utility model. Figure 2 , Figure 3 and Figure 5 As shown, the groove 30 is used to accommodate the welding section 41 of the interconnection strip 40, so that the welding section 41 is welded to the substrate 20 in the groove 30, and then the groove 30 is filled and wrapped with the welding section 41 after a part of the first solder layer 10 is melted.

[0054] In practical applications, there are two situations for the distance between the bottom 31 of the groove 30 and the substrate, that is, there are two situations for the target thickness of the first solder layer 10 at the bottom 31 of the groove 30. In the first situation, the target thickness is zero, and the depth of the groove 30 completely penetrates the entire first solder layer 10, which is the same as the thickness of the first solder layer 10. At this time, the bottom 31 of the groove 30 is the surface of the exposed substrate 20. The welding section 41 of the interconnection bar 40 can be provided with a second solder layer, and the welding section 41 can be directly placed on the bottom 31, that is, on the surface of the exposed substrate 20. When the two are welded, the substrate 20 and the second solder layer are alloyed. Under the diffusion and dissolution of the welding section 41 and the substrate 20 into the liquid second solder, since the distance between the two is close enough, a full IMC layer will be formed between the two. Relying on the high temperature stability of the full IMC layer, the reliability of the high temperature connection between the bus bar and the interconnection bar 40 is improved. The second case is that the target thickness of the first solder layer 10 at the bottom 31 of the groove 30 is greater than zero and less than or equal to the preset thickness. At this time, there is a layer of first solder between the bottom 31 of the groove 30 and the surface of the substrate 20. The welding section 41 of the interconnection bar 40 can be an exposed welding section 41, that is, it is not covered with a second solder layer. When the welding section 41 is directly placed on the bottom 31 of the groove and the two are welded, the welding section 41 and the first solder layer on the bottom 31 are alloyed, and the substrate 20 and the first solder layer are also alloyed. Since the distance between the two is close enough and less than or equal to the preset thickness, as in the first case, a full IMC layer will be formed between the two, thereby improving the reliability of the high-temperature connection between the bus bar and the interconnection bar 40. Both of the above cases can form a Figure 3 The interconnection bar 40 is shown in a state after being welded to the groove bottom 31 of the groove 30 .

[0055] Further, after the interconnection strip 40 is welded to the groove bottom 31 of the groove 30, the first solder layer is melted near the groove 30, and the molten first solder fills the gap between the groove 30 and the welding section 41 of the interconnection strip 40, thereby forming Figure 4 The state of the embedded welding section 41 is shown, Figure 4 It is a schematic diagram of the isometric structure of the busbar and the interconnection bar (after forming the coating layer) according to the embodiment of the utility model. Based on this, a groove 30 is formed on the first solder layer 10, which is equivalent to thinning the first solder layer 10, so that the distance between the surface of the busbar substrate 20 and the welding section 41 of the interconnection bar 40 is small enough, so that the solder joint between the busbar substrate 20 and the interconnection bar 40 can form a full IMC structure, so that the melting point temperature of the solder joint can be increased by at least 232°C relative to the melting point temperature of the busbar solder in the prior art, which can reduce the risk of remelting of the busbar and the interconnection bar due to high temperature, and then reduce the contact area between the two, resulting in increased resistance, or even falling off, thereby improving the high-temperature reliability of the solder joint between the two.

[0056] In some embodiments, an intermetallic compound layer 50 is formed between the welding section 41 and the base 20 located in the groove 30. For example, the welding section 41 of the interconnection bar 40 is made of copper, the base 20 of the busbar is made of copper, and the first solder of the first solder layer 10 is a first tin-based alloy, the first tin-based alloy includes but is not limited to Sn63Pb37, and the melting point is 183°C; the second solder is a second tin-based alloy, the second tin-based alloy includes but is not limited to tin-lead-bismuth, tin-bismuth-silver, indium-tin and other materials, for example, Sn32Pb42Bi26, the melting point is 137°C; Sn27Pb41Bi32, the melting point is 132°C; Sn25Pb38Bi37, the melting point is 132°C; Sn40.5Bi58Ag1.5, the melting point is 138°C.

[0057] When the welding section 41 of the interconnection strip 40 forms a welding point with the substrate 20 through the first solder or the second solder, since the materials on both sides of the first solder or the second solder are copper, the copper on both sides diffuses and dissolves into the liquid solder, and the copper quickly forms an IMC layer with the tin-rich phase in the first solder or the second solder, that is, a copper-IMC-copper structure is formed. Figure 5 As shown, the intermetallic compound layer 50 is a copper-tin intermetallic compound layer, the composition of the IMC layer is Cu6Sn5 and / or Cu3Sn, and the melting point of the IMC layer is 415°C, which is 232°C higher than the melting point of the first solder Sn63Pb37 used in the prior art, and is even higher than the low-temperature solder.

[0058] In order to form a high-temperature resistant IMC layer between the welding section 41 of the interconnection strip 40 and the substrate 20, the preset thickness is 15 μm, that is, when the spacing between the welding section 41 of the interconnection strip 40 and the substrate 20 is less than or equal to 15 μm, for example, the spacing between the two can be 14 μm, 13 μm, 12 μm or 10 μm, etc., a high-temperature resistant IMC layer will be formed between the two through the corresponding solder.

[0059] like Figure 2 As shown, the ratio of the width W of the groove 30 to the diameter of the interconnection bar 40 is in the range of 1.5 to 2, such as 1.5, 1.6, 1.7, 1.8, 1.9 or 2, etc., wherein the width direction of the groove 30 is perpendicular to the extension direction of the interconnection bar 40. That is, the welding section 41 of the interconnection bar 40 is clearance-matched with the groove 30. Through the clearance-matching, when the welding section 41 is welded with the groove bottom 31 of the groove 30, the first solder of the groove 30 on both sides of the welding section 41 will not be affected and melted. When the welding section 41 is too far away from the first solder on both sides of the groove 30, it will be difficult to ensure the complete effect of covering the welding section 41 when the first solder layer 10 is melted to fill the groove 30 later.

[0060] For example, Figure 2 As shown, the depth H of the groove 30 is greater than the diameter of the interconnection bar 40, so as to ensure that there is enough first solder to completely cover the entire welding section 41 after melting, so as to ensure the connection strength. The length L of the groove 30 is greater than half of the width of the busbar, that is, the length of the welding section 41 embedded in the groove 30 is greater than half of the width of the busbar, so as to ensure that the busbar and the interconnection bar 40 have sufficient connection strength after welding. It should be noted that the length direction of the groove 30 and the width direction of the busbar are parallel to the extension direction of the interconnection bar 40.

[0061] Figure 7 Schematic diagram of the top view of the busbar structure according to the embodiment of the utility model. Figure 7 As shown, a plurality of grooves 30 are arranged in the length direction of the busbar, so that a plurality of interconnecting bars 40 are welded to the same busbar, and the length direction of the busbar is perpendicular to the extension direction of the interconnecting bars 40. In the length direction of the busbar, along the direction away from the grooves 30, the thickness of the first solder layer 10 gradually decreases or remains constant.

[0062] When the diameter of the interconnection bar 40 is small, for example, when the diameter of the interconnection bar 40 is less than 0.2 mm, Fig.10 As shown, Fig.10 1 is a schematic diagram of the main structure of a busbar (suitable for interconnection bar diameter d < 0.2 mm) according to an embodiment of the utility model. The thickness of the first solder layer 10 can be constant along the length direction of the interconnection bar 40, that is, it can meet the condition of covering the welding section 41 of the interconnection bar 40. For example, the depth of the groove 30 can be slightly greater than the diameter of the interconnection bar, that is, the diameter d of the welding section 41.

[0063] When the diameter of the interconnection bar 40 is 0.2mm≤d≤0.26mm, or 0.26mm<d, the thickness decreases along the length direction of the busbar away from the groove 30, that is, the thickness is the largest on both sides of the groove 30, and the thickness gradually decreases as the distance from the groove 30 increases, until the thickness reaches the minimum at the position between the two grooves 30, that is, at the position of each groove 30, the top surface 11 of the first solder layer 10 forms a plurality of upwardly protruding ridges to accommodate the embedding of the welding section 41 of the corresponding diameter. It can be understood that as the diameter d of the welding section 41 increases, the protruding height of the ridges also increases accordingly to embed the welding section 41 of the entire interconnection bar 40. For example, when 0.2mm≤d≤0.26mm, the height of the ridges of the busbar is formed as follows: Fig. 9 The status shown, Fig. 9 : is a schematic diagram of the main structure of a busbar (suitable for interconnection bars 0.2mm≤d≤0.26mm) according to an embodiment of the utility model. When the diameter of the interconnection bar 40 is further increased, 0.26mm<d, the height of the ridge of the busbar is further increased to Figure 8 The status shown, Figure 8 The schematic diagram of the main structure of the busbar (suitable for interconnection bars 0.26 mm < d) according to the embodiment of the utility model is shown. Based on this, by increasing the thickness of the first solder layer 10 near the groove 30 instead of increasing the thickness of the first solder layer 10 as a whole, the first solder can be saved, thereby reducing costs.

[0064] The exemplary embodiment of the utility model further provides a photovoltaic module, including a bus bar and a plurality of interconnection bars 40, the bus bar is the bus bar in the above embodiment, the welding section 41 of each interconnection bar 40 is embedded in the corresponding groove 30; when the target thickness is zero, the welding section 41 is coated with a second solder layer 60 formed by a second solder, and the thickness of the second solder layer 60 is greater than 0 and less than or equal to the preset thickness; when the target thickness is greater than zero and less than or equal to the preset thickness, the welding section 41 is a bare welding section 41, that is, the welding section 41 may not be coated with the second solder layer 60. The preset thickness is 15 μm.

[0065] When the target thickness is zero, that is, the bottom of the groove 30 is the surface of the exposed substrate 20, the welding section 41 needs a second solder to be welded to the exposed surface of the substrate 20 to form an IMC layer. Therefore, in this embodiment, the interconnection strip 40, especially the welding section 41, can be coated with a second solder layer 60, and the thickness of the second solder layer 60 should be less than or equal to 15μm, so that when the welding section 41 is placed on the bottom 31 of the groove 30, the distance between the welding section 41 and the exposed surface of the substrate 20 can be suitable for forming the above-mentioned IMC layer.

[0066] In actual use, flux is pre-applied on the bottom 31 of the groove 30 to remove the exposed oxygen-free copper of the substrate 20 and the oxide on the surface of the corresponding solder during welding. The welding section 41 of the interconnection bar 40 is placed in the groove 30, and the welding section 41 is welded to the exposed surface (oxygen-free copper) of the substrate 20. The welding section 41 itself is also copper, and the second solder layer 60 is melted and wetted and spread on the bottom 31 of the groove 30. When both sides are copper, the tin-rich phase of the second solder is quickly transformed into a refractory intermetallic compound layer 50, forming a high-temperature resistant copper-IMC-copper structure.

[0067] When the target thickness is greater than zero and less than or equal to 15 μm, that is, when the bottom of the groove 30 is formed by a layer of the first solder, the welding section 41 of the interconnection bar 40 may not be covered with the second solder layer 60 .

[0068] In actual use, flux is pre-applied on the welding section 41 to remove oxides on the surface of the welding section 41 during welding. The welding section 41 of the interconnection strip 40 is placed in the groove 30, and the welding section 41 and the substrate 20 are welded together through the first solder located at the bottom 31 of the groove. The welding section 41 itself is also copper. The first solder located at the bottom 31 of the groove is melted. Since the first solder at this position is thinner, when both sides are copper, the tin-rich phase of the first solder is quickly transformed into a refractory intermetallic compound layer 50, forming a high-temperature resistant copper-IMC-copper structure.

[0069] In some embodiments, Figure 4 As shown, the busbar further includes a coating layer 13 filled in the groove 30 . The coating layer 13 is formed by at least a portion of the first solder layer 10 . The coating layer 13 covers the welding section 41 and / or the second solder layer 60 .

[0070] When the target thickness is zero, a portion of the first solder layer 10 close to the groove 30 is melted and filled into the groove 30 to form a coating layer 13 to bury the entire welding section 41 and the second solder layer 60 of the welding section 41 to prevent oxidation of the exposed part of the welding section 41 body or the substrate 20 and provide a certain connection strength.

[0071] When the target thickness is greater than zero and less than or equal to 15 μm, a portion of the first solder layer 10 close to the groove 30 is melted and filled into the groove 30 to form a coating layer 13 to bury the entire welding section 41 to prevent oxidation of the welding section 41 and provide a certain connection strength.

[0072] Other technical advantages of the photovoltaic module over the prior art are consistent with the technical advantages of the busbar in the above-mentioned embodiment, which will not be described in detail here.

[0073] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A bus bar, characterized in that: It includes a substrate and a first solder layer formed on the substrate; The first solder layer has grooves formed on the top surface and one side surface for accommodating the welding section of the interconnection strip, and the first solder layer has a target thickness at the bottom of the groove; When the target thickness is zero, the bottom of the groove is used for welding with the welding section through a second solder layer; When the target thickness is greater than zero and less than or equal to a preset thickness, the first solder layer is located at the bottom of the groove for welding the substrate and the welding section; At least a portion of the first solder layer is used to fill the groove and cover the welding section.

2. The bus bar according to claim 1, characterized in that: The preset thickness is 15 μm.

3. The bus bar according to claim 1, characterized in that: The ratio of the width of the groove to the diameter of the interconnection strip is in the range of 1.5 to 2; wherein, The width direction of the groove is perpendicular to the extending direction of the interconnection strip.

4. The bus bar according to claim 1, characterized in that: The depth of the groove is greater than the diameter of the interconnection bar; and / or the length of the groove is greater than half the width of the bus bar; Wherein, the length direction of the groove and the width direction of the bus bar are both parallel to the extension direction of the interconnection bar.

5. The bus bar according to claim 1, characterized in that: The number of the grooves is multiple, and the multiple grooves are arranged along the length direction of the busbar; In the length direction of the busbar, along the direction away from the groove, the thickness of the first solder layer gradually decreases or remains constant; wherein, The length direction of the bus bar is perpendicular to the extending direction of the interconnection bar.

6. A photovoltaic module, characterized in that: Comprising a bus bar and a plurality of interconnection bars, wherein the bus bar is the bus bar according to any one of claims 1 to 5, and the welding section of each interconnection bar is embedded in the corresponding groove; When the target thickness is zero, the welding section is coated with the second solder layer, the thickness of the second solder layer is greater than 0 and less than or equal to the preset thickness, and the welding section is welded to the substrate through the second solder layer; When the target thickness is greater than zero and less than or equal to the preset thickness, the welding section is welded to the substrate through the portion of the first solder layer located at the bottom of the groove.

7. The photovoltaic module according to claim 6, characterized in that: The bus bar further includes a coating layer filled in the groove, wherein the coating layer is formed by at least a portion of the first solder layer, and the coating layer covers the welding section and / or the second solder layer; and / or The preset thickness is 15 μm.

8. The photovoltaic module according to claim 6, characterized in that: An intermetallic compound layer is formed between the welding section and a portion of the substrate located in the groove.

9. The photovoltaic module according to claim 8, characterized in that: The welding section is a welding section made of copper, and the substrate is a substrate made of copper; The first solder layer is made of a first tin-based alloy; The intermetallic compound layer is a copper-tin intermetallic compound layer.

10. The photovoltaic module according to claim 8, characterized in that: When the target thickness is zero, the second solder layer is made of a second tin-based alloy; The intermetallic compound layer is a copper-tin intermetallic compound layer.

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