Photovoltaic ribbon and photovoltaic modules

Abstract

The present invention provides a photovoltaic welding strip and a photovoltaic module, wherein the photovoltaic welding strip comprises a substrate and a coating coated on the outer surface of the substrate, the photovoltaic welding strip is a periodic welding strip segment, and a single period welding strip segment comprises: a first segment body, used to be joined to the front grid line of a photovoltaic cell, wherein the substrate of the first segment body has a square cross section or a square cross section with rounded corners; and a second segment body, used to connect and join adjacent photovoltaic cells. The photovoltaic module comprises at least two photovoltaic cells and the photovoltaic welding strip as described above, wherein the at least two photovoltaic cells are sequentially arranged adjacent to each other through the photovoltaic welding strip.

Description

Technical Field

[0001] The invention relates to the field of photovoltaics, and in particular to a photovoltaic welding strip and a photovoltaic module. Background Art

[0002] Photovoltaic modules are used to convert solar energy into electrical energy. The photovoltaic modules include multiple photovoltaic cells, and two adjacent photovoltaic cells are connected in series through welding strips. The welding strip generally includes a welding strip base (or welding strip body) and a coating coated on the outer surface of the welding strip base. In early photovoltaic welding strips, the welding strip base often uses a conductive substrate with a flat rectangular cross-section (such as a copper strip), but with the increase in the number of main grids on photovoltaic cells, for example, the current multi-main grid battery generally has more than 9 grid lines, and the corresponding main grid width is also narrower. This traditional rectangular flat welding strip has a low utilization rate of light due to its large shading area.

[0003] In order to reduce the shading area, current multi-main-grid cells often use a thinner circular conductive substrate (such as a copper substrate) as the solder strip substrate. However, the conventional circular copper substrate is thinner and has a higher resistance, resulting in a certain loss of component power due to the higher resistance. If the diameter of the circular solder strip is increased, the fragmentation rate of the battery and the hidden crack rate of the component will increase, reducing the long-term reliability of the component and increasing the manufacturing cost of the component. In addition, due to the small contact area when the circular solder strip is welded to the battery cell, it is easy to produce defects such as cold solder joints and low welding tension, and the process stability during the series welding process is not high enough. Furthermore, due to the small surface tension of the circular copper substrate, the uniformity and stability of the coating thickness are always low, which will result in low welding tension after the solder strip is welded to the battery cell. Summary of the invention

[0004] In order to solve the above technical problems, the present invention discloses a photovoltaic welding strip and a photovoltaic module, which change the shape of the existing conductive substrate into a square or a quasi-square (for example, a square with rounded corners), thereby increasing the cross-sectional area of ​​the conductive substrate and reducing the resistance under the condition that the width (or diameter) and thickness of the welding strip remain unchanged. In addition, compared with a circular conductive substrate, the contact area between the welding strip and the welding point is increased, the cold solder joint is reduced, the welding tension is increased, the reliability of the module is improved, the surface tension of the substrate is increased, and the uniformity and stability of the coating thickness are improved.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention provides a photovoltaic welding strip, which includes a substrate and a coating coated on the outer surface of the substrate, wherein the photovoltaic welding strip is a periodic welding strip segment, and a single period of welding strip segments includes: a first segment body, used to be joined to the front grid line of a photovoltaic cell, wherein the substrate of the first segment body has a square cross-section or a square cross-section with rounded corners; and a second segment body, used to connect and join adjacent photovoltaic cells.

[0006] By adopting a solder strip substrate with a square cross-section or a square with rounded corners, the cross-sectional area of ​​the conductive substrate is increased and the resistance is reduced without changing the width (or diameter) and thickness of the solder strip. In addition, compared with a circular conductive substrate, the contact area between the solder strip and the solder joint is increased, the cold solder joint is reduced, the welding tension is increased, the component reliability is improved, the surface tension of the substrate is increased, and the uniformity and stability of the coating thickness are improved.

[0007] Furthermore, the base of the first section includes a bonding surface and a non-bonding surface, wherein the bonding surface is used to bond with the photovoltaic cell sheet, wherein the coating coated on the bonding surface and the coating coated on the non-bonding surface are different types of coatings.

[0008] By coating different types of coatings on the non-joint surface and the joint surface respectively, the light reflectivity of the non-joint surface and the conductivity and bonding property of the joint surface can be specifically improved.

[0009] Furthermore, the coating applied on the joint surface is a conductive adhesive, and a longitudinal guide groove and a transverse guide groove intersecting with the longitudinal guide groove are provided on the joint surface of the base of the first section.

[0010] By arranging longitudinal guide grooves and transverse guide grooves on the joint surface, the uniformity of the conductive adhesive coating is improved, thereby providing a better joint effect.

[0011] Further, in a cross section, the coating applied on the outer surface of the substrate of the first section has a circular outer contour.

[0012] By applying the coating with a rounded outer contour, the light reflectivity of the non-joint surface of the first segment is improved.

[0013] Furthermore, the second segment includes a third segment and a fourth segment, the third segment is used to be arranged between two adjacent photovoltaic cells, and the fourth segment is used to be joined to the back side of adjacent photovoltaic cells, wherein the third segment is a flat welding strip segment that has been flattened.

[0014] By flattening the segment body arranged between two adjacent photovoltaic cell sheets, the sheet spacing is reduced.

[0015] Furthermore, the second segment is a flat welding strip segment that has been flattened, and the second segment includes a third segment and a fourth segment, the third segment is used to be arranged between two adjacent photovoltaic cells, and the fourth segment is used to be joined to the back side of adjacent photovoltaic cells, and the thickness of the third segment is less than or equal to the thickness of the fourth segment.

[0016] By flattening the second section body connecting and joining adjacent photovoltaic cells, the joining strength with the adjacent photovoltaic cells is enhanced and the distance between the cells is reduced.

[0017] Furthermore, the base of the first section includes a joining surface and a non-joining surface, the joining surface is used to join with the photovoltaic cell sheet, the joining surface has a concave structure, and the non-joining surface includes a side surface and a top surface, at least one of the side surface and the top surface has a concave structure.

[0018] By making the top surface of the joining surface and / or the non-joining surface concave, the coating can be accumulated to improve the joining reliability with the battery cell; by making the side surface of the non-joining surface concave, the convexity of the solder strip base can be reduced or eliminated, and the light reflection amount can be increased.

[0019] Furthermore, the base of the first section includes a joining surface and a non-joining surface, the joining surface is used to join with the photovoltaic cell sheet, the joining surface has a plurality of concave grooves, and the non-joining surface includes a side surface and a top surface, at least one of the side surface and the top surface has a plurality of concave grooves.

[0020] By providing the top surface of the bonding surface and / or the non-bonding surface with a plurality of inward-concave grooves, the accumulated coating can be dispersed, ensuring uniform distribution of the coating and improving the reliability of bonding with the battery cell; by providing the side surface of the non-bonding surface with a plurality of inward-concave grooves, the accumulated coating can be dispersed, ensuring uniform distribution of the coating, reducing the protrusion of the coating, reducing light obstruction and increasing the amount of light reflection.

[0021] A further embodiment of the present invention further provides a photovoltaic assembly, which includes at least two photovoltaic cells and the photovoltaic welding strip as described above, wherein the at least two photovoltaic cells are sequentially adjacently arranged via the photovoltaic welding strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A and Figure 1B It is a schematic diagram of the connection state of the photovoltaic cell and the welding ribbon;

[0023] Figure 2A and Figure 2B is a schematic diagram of a circular conductive substrate in the prior art and a square conductive substrate of the present invention;

[0024] Figure 3 is a cross-sectional view of a first section of a photovoltaic ribbon according to the present invention;

[0025] Figure 4 is a top view of a bonding surface of a base of a first section of a photovoltaic welding strip according to the present invention;

[0026] Figure 5A and Figure 5B is a cross-sectional view showing a base of a first segment of a photovoltaic welding ribbon according to the present invention;

[0027] Fig. 6A and Figure 6B It is a cross-sectional view of a square conductive substrate with rounded corners and a first section of a photovoltaic welding ribbon made therefrom according to another embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these embodiments.

[0029] The technical solution of the present invention provides a photovoltaic welding strip, which includes a substrate and a coating coated on the outer surface of the substrate. The photovoltaic welding strip is a periodic welding strip segment, and a single period of welding strip segments includes: a first segment body, used to be joined to the front grid line of a photovoltaic cell, wherein the substrate of the first segment body has a square cross-section or a square cross-section with rounded corners; and a second segment body, used to connect and join adjacent photovoltaic cells.

[0030] By adopting a solder strip substrate with a square cross-section or a square with rounded corners, the cross-sectional area of ​​the conductive substrate is increased and the resistance is reduced without changing the width (or diameter) and thickness of the solder strip. In addition, compared with a circular conductive substrate, the contact area between the solder strip and the solder joint is increased, the cold solder joint is reduced, the welding tension is increased, the component reliability is improved, the surface tension of the substrate is increased, and the uniformity and stability of the coating thickness are improved.

[0031] Furthermore, the base of the first section includes a bonding surface and a non-bonding surface, wherein the bonding surface is used to bond with the photovoltaic cell sheet, wherein the coating coated on the bonding surface and the coating coated on the non-bonding surface are different types of coatings.

[0032] By coating different types of coatings on the non-joint surface and the joint surface respectively, the light reflectivity of the non-joint surface and the conductivity and bonding property of the joint surface can be specifically improved.

[0033] Furthermore, the coating applied on the joint surface is a conductive adhesive, and a longitudinal guide groove and a transverse guide groove intersecting with the longitudinal guide groove are provided on the joint surface of the base of the first section.

[0034] By arranging longitudinal guide grooves and transverse guide grooves on the joint surface, the uniformity of the conductive adhesive coating is improved, thereby providing a better joint effect.

[0035] Further, in a cross section, the coating applied on the outer surface of the substrate of the first section has a circular outer contour.

[0036] By applying the coating with a rounded outer contour, the light reflectivity of the non-joint surface of the first segment is improved.

[0037] Furthermore, the second segment includes a third segment and a fourth segment, the third segment is used to be arranged between two adjacent photovoltaic cells, and the fourth segment is used to be joined to the back side of adjacent photovoltaic cells, wherein the third segment is a flat welding strip segment that has been flattened.

[0038] By flattening the segment body arranged between two adjacent photovoltaic cell sheets, the sheet spacing is reduced.

[0039] Furthermore, the second segment is a flat welding strip segment that has been flattened, and the second segment includes a third segment and a fourth segment, the third segment is used to be arranged between two adjacent photovoltaic cells, and the fourth segment is used to be joined to the back side of adjacent photovoltaic cells, and the thickness of the third segment is less than or equal to the thickness of the fourth segment.

[0040] By flattening the second section body connecting and joining adjacent photovoltaic cells, the joining strength with the adjacent photovoltaic cells is enhanced and the distance between the cells is reduced.

[0041] Furthermore, the base of the first section includes a joining surface and a non-joining surface, the joining surface is used to join with the photovoltaic cell sheet, the joining surface has a concave structure, and the non-joining surface includes a side surface and a top surface, at least one of the side surface and the top surface has a concave structure.

[0042] By making the top surface of the joining surface and / or the non-joining surface concave, the coating can be accumulated to improve the joining reliability with the battery cell; by making the side surface of the non-joining surface concave, the convexity of the solder strip base can be reduced or eliminated, and the light reflection amount can be increased.

[0043] Furthermore, the base of the first section includes a joining surface and a non-joining surface, the joining surface is used to join with the photovoltaic cell sheet, the joining surface has a plurality of concave grooves, and the non-joining surface includes a side surface and a top surface, at least one of the side surface and the top surface has a plurality of concave grooves.

[0044] By providing the top surface of the bonding surface and / or the non-bonding surface with a plurality of inward-concave grooves, the accumulated coating can be dispersed, ensuring uniform distribution of the coating and improving the reliability of bonding with the battery cell; by providing the side surface of the non-bonding surface with a plurality of inward-concave grooves, the accumulated coating can be dispersed, ensuring uniform distribution of the coating, reducing the protrusion of the coating, reducing light obstruction and increasing the amount of light reflection.

[0045] A further embodiment of the present invention further provides a photovoltaic assembly, which includes at least two photovoltaic cells and the photovoltaic welding strip as described above, wherein the at least two photovoltaic cells are sequentially adjacently arranged via the photovoltaic welding strip.

[0046] See also Figure 1A and Figure 1B , which shows the connection status of the photovoltaic cell 90 and the welding ribbon 1, the photovoltaic welding ribbon 1 includes a first segment 101 for bonding to the front grid line of the photovoltaic cell 90 and a second segment for connecting and bonding adjacent photovoltaic cells.

[0047] from Figure 1A It can be seen that the width of the soldering ribbon 1 (specifically, the first segment 101 ) determines its light shielding area, and the width of the soldering ribbon 1 directly depends on the width or diameter of the soldering ribbon base (conductive substrate).

[0048] See also Figure 2A and Figure 2B , which respectively show a circular conductive substrate and a square conductive substrate with the same width (or diameter) and thickness d. Obviously, when the width and thickness d of the conductive substrate are the same, the cross-sectional area of ​​the square conductive substrate is larger than the cross-sectional area of ​​the circular conductive substrate. Therefore, when the square conductive substrate and the circular conductive substrate with the same width and thickness are used to make the photovoltaic welding strip 1, the resistance of the square conductive substrate with a larger cross-sectional area is smaller than the resistance of the circular conductive substrate.

[0049] In the embodiment of the present invention, as for the conductive substrate, a metal substrate or a metal alloy substrate can be selected, such as a pure copper substrate, a copper-silver alloy substrate, etc. Preferably, a pure copper substrate can be selected in consideration of cost performance.

[0050] A photovoltaic solder strip is formed by further coating a coating (e.g., a solder coating) on ​​the surface of the square conductive substrate. For example, an alloy layer (e.g., a tin-lead alloy layer) can be formed on the outer surface of the square conductive substrate by hot dipping to achieve a conductive connection with the photovoltaic cell (e.g., by welding).

[0051] See also Figure 3 , which shows the use of Figure 2B The cross-sectional view of a photovoltaic ribbon made of a square conductive substrate is shown. Figure 3 As shown, the photovoltaic ribbon comprises a ribbon base 10 (ie, a square conductive substrate) and a coating 20 coated on the outer surface of the ribbon base 10 .

[0052] As described above, by using a square conductive substrate as the substrate of the photovoltaic welding strip, the cross-sectional area of ​​the conductive substrate is increased while the overall width and thickness of the welding strip remain unchanged, thereby reducing the resistance and further reducing the power loss of the module due to the resistance. In addition, compared with the circular conductive substrate, the contact area between the welding strip and the welding point is increased, the cold welding is reduced, the welding tension is increased, the reliability of the module is improved, and the surface tension of the substrate is increased, and the uniformity and stability of the coating thickness are improved.

[0053] Regarding the coating 20 coated on the outer surface of the solder strip substrate 10, considering the reflectivity, preferably, in the cross section, the coating 20 can have a circular outer contour. It can be understood that the outer contour shape of the coating 20 is not limited thereto, and the outer contour shape of the coating 20 can be flexibly set according to the reflectivity.

[0054] Further, see Figure 3 The substrate 10 of the first section of the photovoltaic welding ribbon may include a bonding surface 102 for bonding with the photovoltaic cell sheet and a non-bonding surface 101, wherein the coating coated on the non-bonding surface 101 and the coating coated on the bonding surface 102 may be different or similar coatings to specifically improve the reflectivity of the non-bonding surface, and the conductivity and bonding force of the bonding surface. For example, a tin-lead alloy or resin-based reflective coating may be coated on the non-bonding surface 101, and a conductive adhesive may be coated on the bonding surface 102 for low-temperature bonding.

[0055] When the conductive adhesive is applied to the bonding surface 102 of the solder strip substrate, in order to ensure the uniformity of the conductive adhesive coating and the bonding reliability, as shown in FIG. Figure 4 As shown, a longitudinal guide groove 301 and a transverse guide groove 302 may be provided on the joint surface of the solder strip substrate, and the longitudinal guide groove 301 intersects with the transverse guide groove 302 so that the conductive adhesive in the longitudinal guide groove 301 can flow transversely, thereby improving the uniformity of the conductive adhesive and providing a better welding effect. There is no clear limitation on the specific number of the longitudinal guide groove 301 and the transverse guide groove 302, which may be one or more.

[0056] As for the first section of the photovoltaic welding ribbon, as described above, it includes a joint surface 102 and a non-joint surface 101, wherein the non-joint surface 101 includes a side surface 1011 and a top surface 1012, for example, see Figure 5A and Figure 5B .

[0057] In the embodiment of the present invention, the second section of the photovoltaic welding ribbon may be the same as the first section, that is, including a substrate with a square cross section and a coating coated on the outer surface of the substrate.

[0058] When the second segment is the same as the first segment, in order to ensure the bonding strength between the welding strip and the front and back sides of the photovoltaic cell, preferably, the bonding surface 102 of the first segment has a concave structure, and the top surface 1012 of the non-bonding surface 101 of the first segment also has a concave structure, so that the coating can be accumulated to improve the bonding reliability with the cell.

[0059] Furthermore, the side surface 1011 of the joint surface 101 of the first segment may also have a concave structure to reduce or eliminate the convexity of the solder strip substrate and increase the light reflection amount.

[0060] The shape of the concave structure may be a semicircular, elliptical or trapezoidal concave structure, etc., and the specific shape is not limited in any way.

[0061] Alternatively, the bonding surface 102 of the first segment has a plurality of inwardly concave grooves, and the top surface 1012 of the non-bonding surface 101 of the first segment also has a plurality of inwardly concave grooves, thereby being able to disperse the accumulated coating and ensure uniform distribution of the coating to improve bonding reliability with the battery cell.

[0062] Furthermore, the side surface 1011 of the joint surface 101 of the first segment body may also have a plurality of inwardly concave grooves to disperse the accumulated coating, ensure uniform distribution of the coating, reduce protrusions of the coating, reduce light blocking, and increase light reflection.

[0063] Likewise, it is understood that the shape of the groove is not particularly limited.

[0064] In a further embodiment of the present invention, preferably, in order to take into account both the reflective effect and the welding effect of the welding strip, a conductive substrate with a square cross section with rounded corners (or a square with rounded corners, a square with R corners) can be selected as the substrate of the photovoltaic welding strip of the present invention. Fig. 6A , which shows a conductive substrate having a square cross-section with rounded corners. Fig. 6A As shown, the rounded square has four rounded corners, and the radius of the arc corresponding to each rounded corner is R.

[0065] Compared with a square conductive substrate, a square conductive substrate with rounded corners has a simpler manufacturing process and is easier to form a reflective coating with a circular outer contour on its outer surface. In addition, compared with a circular conductive substrate, the bonding degree with the photovoltaic cell is higher. Therefore, as a preferred technical solution, a square conductive substrate with rounded corners can be selected to make the photovoltaic welding strip of the present invention.

[0066] 6 , which shows a photovoltaic welding ribbon formed by a square conductive substrate with rounded corners. In the embodiment shown in FIG. 6 , the coating coated on the outer surface of the square conductive substrate with rounded corners has a circular outer contour.

[0067] As described above, the second section of the photovoltaic welding ribbon may be the same as the first section, that is, including a base having a square cross section or a square cross section with rounded corners and a coating coated on the outer surface of the base.

[0068] Preferably, if Figure 1A and Figure 1BAs shown, the second segment may include a third segment 103 and a fourth segment 104, the third segment 103 is used to be arranged between two adjacent photovoltaic cells, and the fourth segment 104 is used to be joined to the back side of adjacent photovoltaic cells, wherein the third segment 103 is a flat welding strip segment that has been flattened to reduce the spacing between adjacent photovoltaic cells.

[0069] Alternatively, in order to enhance the bonding strength between the fourth segment 104 of the photovoltaic welding ribbon and the adjacent photovoltaic cell, the fourth segment of the photovoltaic welding ribbon may also be flattened so that the fourth segment has a flat cross section, thereby increasing the contact area with the adjacent photovoltaic cell to improve the bonding strength. In addition, in order to further reduce the spacing between adjacent photovoltaic cells, the thickness of the third segment 103 may be less than or equal to the thickness of the fourth segment 104.

[0070] An embodiment of the present invention further provides a photovoltaic assembly, which includes at least two photovoltaic cells and the photovoltaic welding strip as described above, wherein the at least two photovoltaic cells are sequentially adjacently arranged via the photovoltaic welding strip.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A photovoltaic welding ribbon, characterized in that: The photovoltaic welding ribbon comprises a substrate and a coating coated on the outer surface of the substrate. The photovoltaic welding ribbon is a periodic welding ribbon segment. A single periodic welding ribbon segment comprises: A first segment body, used for bonding to the front grid line of the photovoltaic cell, wherein the base of the first segment body has a square cross section or a square cross section with rounded corners; and The second segment is used to connect and join adjacent photovoltaic cells; wherein, The base of the first section body includes a joint surface and a non-joint surface, the joint surface is used to join with the photovoltaic cell sheet, the joint surface has a concave structure, and the non-joint surface includes a side surface and a top surface, the side surface and the top surface have a concave structure; The second segment is a flat welding strip segment that has been flattened, and the second segment includes a third segment and a fourth segment. The third segment is used to be arranged between two adjacent photovoltaic cells, and the fourth segment is used to be joined to the back of adjacent photovoltaic cells. The thickness of the third segment is less than or equal to the thickness of the fourth segment.

2. The photovoltaic welding strip according to claim 1, characterized in that: The base of the first section includes a bonding surface and a non-bonding surface, wherein the bonding surface is used for bonding with the photovoltaic cell sheet, wherein the coating coated on the bonding surface and the coating coated on the non-bonding surface are different types of coatings.

3. The photovoltaic welding strip according to claim 2, characterized in that: The coating coated on the joint surface is conductive glue, and the joint surface of the base of the first section body is provided with a longitudinal guide groove and a transverse guide groove intersecting with the longitudinal guide groove.

4. The photovoltaic welding ribbon according to claim 1, characterized in that: In cross section, the coating applied on the outer surface of the substrate of the first section has a circular outer contour.

5. The photovoltaic welding strip according to any one of claims 1 to 4, characterized in that: The second segment includes a third segment and a fourth segment, wherein the third segment is used to be arranged between two adjacent photovoltaic cells, and the fourth segment is used to be joined to the back of adjacent photovoltaic cells, wherein the third segment is a flat welding strip segment that has been flattened.

6. The photovoltaic welding ribbon according to claim 1, characterized in that: The base of the first section includes a bonding surface and a non-bonding surface, the bonding surface is used to bond with the photovoltaic cell sheet, the bonding surface has a plurality of concave grooves, and the non-bonding surface includes a side surface and a top surface, at least one of the side surface and the top surface has a plurality of concave grooves.

7. A photovoltaic module, characterized in that: The invention comprises at least two photovoltaic cells and the photovoltaic welding strip according to any one of claims 1 to 6, wherein the at least two photovoltaic cells are arranged adjacent to each other in sequence through the photovoltaic welding strip.

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