Battery string and photovoltaic module
By setting through curved grooves at the edges of the solar cells and optimizing the embedding method of the solder strips, the problem of hidden cracks and fragments in the solar cells was solved, improving the reliability and quality of the solar cell strings and photovoltaic modules.
Patent Information
- Application Number
- CN202520223666.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-12
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2035-02-12
AI Technical Summary
When using solar cells with electrodes on both sides to string together to prepare solar cell strings and photovoltaic modules, the contact stress of the solder ribbon between adjacent solar cells leads to a high risk of microcracks and fragmentation of the solar cells, which is especially prominent in module products that pursue smaller cell spacing.
A groove is provided on the edge of the battery cell that runs through both the front and back sides. The sidewall of the groove is curved and tangent to the sidewall of the battery cell. The solder strip is embedded in the groove to reduce contact stress. The solder strip is flat in the groove area to optimize the contact method between the solder strip and the battery cell.
This reduces the contact stress between the solder ribbon and the solar cell, decreases the risk of microcracks and fragments, and improves the reliability of the solar cell string and the quality of the photovoltaic module.
Smart Images
Figure CN223758667U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of photovoltaic manufacturing, in particular to a cell string and a photovoltaic module. BACKGROUND
[0002] When a cell string and a photovoltaic module are prepared by string welding of cell pieces with electrodes on both front and back surfaces, contact stress is generated at the inter-piece gap part when the welding strip passes between two adjacent cell pieces, which easily leads to hidden crack fragments of the cell pieces in the subsequent laminating process.
[0003] With the pursuit of smaller inter-piece spacing in the photovoltaic industry, the risk of hidden crack fragments of the cell pieces is more prominent. CONTENT OF THE UTILITY MODEL
[0004] The present application provides a cell string and a photovoltaic module, aiming to solve the problem of high risk of hidden crack fragments in the string welding of traditional cell pieces.
[0005] In a first aspect, the embodiments of the present application provide a cell string, comprising cell pieces and a welding strip, the front surface and the back surface of the cell piece are provided with an electrical connection part, the welding strip is electrically connected with the electrical connection part to connect a plurality of cell pieces to form the cell string.
[0006] At least one edge of the cell piece is provided with a groove corresponding to the welding strip along the extension direction of the welding strip, and the groove penetrates the front surface and the back surface of the cell piece.
[0007] The opening of the groove faces the outside of the cell piece, both side walls of the groove are first curved surfaces, and both side walls of the groove are tangent to the side wall of the cell piece.
[0008] Optionally, the electrical connection part is a main grid, and at least one end of the main grid along the extension direction of the main grid and located at the edge of the cell piece is provided with a groove corresponding to the main grid.
[0009] Optionally, the bottom between the two side walls of the groove is a second curved surface, and both the first curved surfaces are tangent to the second curved surface.
[0010] Optionally, the projection of the groove along the thickness direction of the cell piece includes a first curve formed by the first curved surface and a second curve formed by the second curved surface.
[0011] Both the first curve and the second curve are circular arcs, the radius of the first curve is R1, and the radius of the second curve is R2.
[0012] Optionally, the welding strip is embedded through the groove, and the welding strip is flat at the groove part.
[0013] Optionally, the radius R2 of the second curve satisfies the following expression: R2≥πr 2 wherein r represents the radius of the solder strip, and d represents the thickness of the solder strip at the groove position.
[0014] Optionally, 0.07mm≤d≤0.14mm.
[0015] Optionally, the radius R2 of the second curve further satisfies the following expression: (R2+s) / h≥3.87; wherein h represents the thickness of the battery piece, and s represents the spacing between adjacent battery pieces in the string welding direction.
[0016] Optionally, s>0.6mm.
[0017] In a second aspect, the embodiments of the present application further provide a photovoltaic module, comprising the battery string of the first aspect.
[0018] In the embodiments of the present application, by arranging the groove at the edge of the battery piece, the two side walls of the groove are both first curved surfaces, and the first curved surfaces corresponding to the two side walls are both tangent to the side wall of the battery piece, so that the corner is avoided to be formed at the transition position between the opening of the groove and the side wall of the battery piece, and the stress concentration phenomenon at the position can be reduced, which helps to reduce the hidden cracks of the battery piece caused by the contact stress between the solder strip and the battery piece during string welding, and the reliability of the string welding can be improved. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0020] Figure 1 A schematic diagram of string welding connection of adjacent battery pieces in the embodiments of the present application is shown;
[0021] Figure 2 A perspective schematic diagram of a battery piece without main grid in the embodiments of the present application is shown;
[0022] Figure 3 A perspective schematic diagram of a battery piece with main grid in the embodiments of the present application is shown;
[0023] Figure 4 A planar schematic diagram of the battery piece of Figure 3 in the embodiments of the present application is shown;
[0024] Figure 5 A schematic diagram of the arrangement of the battery pieces of Figure 3 in the embodiments of the present application to form a battery string is shown.
[0025] Figure 6 A partial enlarged view of the I position of the embodiment of the application is shown. Figure 4
[0026] Figure 7 A profile view of a groove shape of the embodiment of the application is shown.
[0027] Figure 8 A cross-section variation view of a solder strip of the embodiment of the application is shown.
[0028] Figure 9 A cross-section view along a direction parallel to the solder strip of the embodiment of the application is shown. Figure 1
[0029] Explanation of figure numbers:
[0030] Battery piece-10, solder strip-20, main grid-101, groove-102, side wall-1021, bottom-1022, first curve-1021a, second curve-1022a. DETAILED DESCRIPTION
[0031] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some but not all of the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the application.
[0032] With reference to Figures 1 to 6 , the embodiment of the application provides a battery string, comprising a battery piece 10 and a solder strip 20, the front surface and the back surface of the battery piece 10 are provided with an electrical connection part, the solder strip 20 is electrically connected with the electrical connection part to connect a plurality of the battery pieces 10 to form the battery string.
[0033] At least one edge of the battery piece 10 is provided with a groove 102 corresponding to the solder strip 20 along the extension direction of the solder strip 20, the groove 102 penetrates the front surface and the back surface of the battery piece 10.
[0034] The opening of the groove 102 faces the outside of the battery piece 10, the two side walls 1021 of the groove 102 are both first curved surfaces, and the two side walls 1021 of the groove 102 are tangent to the side walls of the battery piece 10.
[0035] The battery piece 10 used in the battery string in the embodiment of the application can be a battery piece without a main grid or a battery piece with a main grid, and both can be connected by the solder strip 20. Figure 1 For example, the adjacent battery pieces 10 are connected together by welding with the welding ribbons 20. Figure 2 As shown in the diagram, when the battery piece 10 is a 0BB type of battery without main grids, the electrical connection part can include the pads arranged in an array on the surface of the battery piece 10, and the electrical connection part is electrically connected with the fine grids on the surface of the battery piece 10. The pads can also be used for welding with the welding ribbons 20, and the shape of the pads is not limited to a circle or a rectangle. Figure 3 As shown in the diagram, when the battery piece 10 is an MBB type of battery with main grids, the electrical connection part can also include the plurality of main grids 101 arranged in parallel on the surface of the battery piece 10, and the main grids 101 are used for collecting the current from the fine grids and can be transmitted to the welding ribbons through the pads.
[0036] Therefore, the type of the battery piece 10 in the embodiment of the application can be a 0BB or MBB type of battery piece.
[0037] In the battery string, there is an inter-piece spacing between the adjacent battery pieces 10 along the extension direction of the welding ribbons 20. In the case of a fixed size of the photovoltaic module, if the inter-piece spacing is too large, the area of the battery piece 10 will be small. Therefore, reducing the inter-piece spacing can provide space for increasing the area of the battery piece 10, which is helpful to increase the power of the photovoltaic module. At the same time, the reduction of the inter-piece spacing also increases the contact stress between the welding ribbons 20 and the battery piece 10 located between the adjacent battery pieces 10, which increases the risk of the hidden cracking of the battery piece 10.
[0038] Therefore, the structure of the conventional battery piece 10 is improved in the embodiment of the application, as shown in the diagrams of Figure 1 and Figure 2 , a groove 102 is arranged at the edge of the battery piece 10 along the extension direction Y of the welding ribbons 20. The groove 102 is located in the extension direction Y of the welding ribbons 20, and the number of the grooves 102 is the same as the number of the welding ribbons 20.
[0039] As shown in the diagrams of Figure 4 and Figure 5 , the groove 102 can be located at only one end of the extension direction of the welding ribbons 20, for example, the A end or the B end shown in the diagrams. At this time, the battery piece 10 with the groove 102 at only one end can be arranged at the head end or the tail end of the battery string, so that the one end with the groove 102 faces the middle part of the battery string, and is used for series welding with other battery pieces 10.
[0040] As shown in the diagrams of Figure 4 and Figure 5 , the groove 102 can also be located at both ends of the extension direction of the welding ribbons 20, for example, the A end and the B end shown in the diagrams. At this time, the battery piece 10 with the groove 102 at both ends can be arranged at the middle part of the battery string, and both ends are connected with other battery pieces 10 through the welding ribbons 20.
[0041] Figure 6Also shown in the utility model embodiment Figure 4 The recess 102 is towards the outside of the battery piece 10, both side walls 1021 of the recess 102 are first curved surfaces, and the first curved surfaces of the two side walls 1021 are tangent to the side wall of the battery piece 10, thereby avoiding the formation of an edge at the transition between the opening of the recess 102 and the side wall of the battery piece 10, reducing stress concentration at this location, and helping to reduce the contact stress between the solder strip 20 and the battery piece 10 during string welding, which can cause the battery piece 10 to crack, thereby improving the reliability of string welding.
[0042] Optionally, as shown in Figure 3 and Figure 4 , the electrical connection portion is a main grid 101, and at least one end of the main grid 101 in the extension direction of the main grid 101 is provided with a recess 102 corresponding to the main grid 101 at the edge of the battery piece 10.
[0043] Specifically, Figure 3 is an axonometric view of a battery piece 10 of the MBB type, which is a battery piece having a main grid 101 on both the front and back surfaces, and the main grid 101 is part of the electrical connection portion. For example, the main grids 101 on the front surface of the battery piece 10 correspond to the positive or negative electrode of the battery piece, and the main grids 101 on the back surface correspond to the negative or positive electrode of the battery piece. The battery pieces 10 of the present application can be arranged in a row for string welding to obtain a battery string.
[0044] In combination with the foregoing embodiments, when this type of battery piece 10 is used for string welding, a recess 102 is provided at the edge of the battery piece 10 in the extension direction Y of the main grid 101, and the recess 102 is located in the extension direction Y of the main grid 101, and the number of recesses 102 is the same as the number of main grids 101.
[0045] By providing a recess 102 at the edge of the MBB type battery piece 10, the reliability of the MBB type battery piece 10 for string welding can be improved, which helps to improve the quality of the photovoltaic module.
[0046] Optionally, referring to Figure 6 , the bottom 1022 between the two side walls 1021 of the recess 102 is a second curved surface, and both the first curved surfaces are tangent to the second curved surface.
[0047] Specifically, as shown in Figure 6As shown, in the battery piece 10 in the embodiment of the utility model, in addition to the two side walls 1021 of the groove 102 being curved surface shape, the bottom 1022 between the two side walls 1021 can also be curved surface shape, it can be the same or different second curve as the first curve, and the first curve on both sides of the second curve is tangent to the second curve, which can ensure that the entire inner wall of the groove 102 is smooth without edges and corners, which helps to further reduce the contact stress of the welding strip 20 and the inner wall of the groove 102.
[0048] Optionally, referring to Figure 7 , along the projection of the thickness direction of the battery piece 10, the profile of the groove 102 includes a first curve 1021a formed by the first curved surface and a second curve 1022a formed by the second curved surface.
[0049] The first curve 1021a and the second curve 1022a are both circular arcs, the radius of the first curve 1021a is R1, and the radius of the second curve 1022a is R2.
[0050] Specifically, the cross-sectional shape of the groove 102 on the battery piece 10 in the embodiment of the utility model can be Figure 7 a profile formed by connecting three segments of curves, wherein the first curve 1021a is the projection of the first curved surface along the thickness direction of the battery piece 10, and the second curve 1022a is the projection of the second curved surface along the thickness direction of the battery piece 10. As described above in the first curved surface and the second curved surface in the foregoing embodiments, it is easy to know that the two first curves 1021a are located on both sides of the second curve 1022a and are tangent to the second curve 1022a.
[0051] As Figure 7 illustrated, the first curve 1021a in the middle and the second curve 1022a on both sides are both circular arcs, the radius of the first curve 1021a is R1, and the radius of the second curve 1022a is R2. The standard circular arc corresponding to this standard circular shape is easier to manufacture than other function curves, and the processing cost is lower. In addition, since the welding strip 20 is basically completely in the width interval corresponding to the second curve 1022a along the width direction, the first curve 1021a is the transition part of the groove 102 and the side wall of the battery piece 10, therefore, the radius R2 of the second curve 1022a is greater than the radius R1 of the first curve 1021a.
[0052] Optionally, referring to Figure 8 , the welding strip 20 is embedded through the groove 102, and the welding strip 20 is in a flat shape at the groove 102 part.
[0053] Specifically, in an embodiment, as Figure 8As shown, the welding strip 20 for string welding in the embodiment of the utility model can be a round wire welding strip with a mostly circular cross section, and the welding strip 20 can be flattened at the part located in the groove 102 before string welding, so that the cross section of the welding strip 20 corresponding to the groove 102 is in a rectangular shape, thereby enabling the welding strip 20 to be in surface contact with the surface of the battery piece, reducing the contact stress and lowering the risk of hidden cracks.
[0054] Optionally, the radius R2 of the second curve 1022a satisfies the following expression: R2≥πr 2 / (2d); wherein r represents the radius of the welding strip 20, and d represents the thickness of the welding strip 20 at the part of the groove 102.
[0055] Specifically, in one embodiment, as shown, Figure 8 for the welding strip 20, before the local flattening treatment, the radius of the circular part of the welding strip 20 is r, and the cross-sectional area is πr 2 , and after flattening, the width of the rectangular cross section is w, and the thickness is d, and πr 2 =w*d.
[0056] In order to ensure that the welding strip 20 is completely in the space corresponding to the second curve 1022a along the width direction, 2R2≥w, that is, the radius R2 of the second curve 1022a needs to satisfy R2≥πr 2 / (2d), so as to provide sufficient accommodation space for the welding strip 20 in the X direction. Figure 7
[0057] Exemplarily, the thickness of the welding strip 20 after flattening can be any parameter between 0.07mm and 0.14mm, for example, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm.
[0058] Optionally, the radius R2 of the second curve also satisfies the following expression: (R2+s) / h≥3.87; wherein h represents the thickness of the battery piece, and s represents the spacing between adjacent battery pieces 10 along the string welding direction.
[0059] Specifically, in one embodiment, as shown, Figure 1 and Figure 9 As shown, with the arrangement design that the spacing s between the adjacent battery pieces 10 is smaller and smaller, the bending angle of the welding strip 20 tends to increase when the welding strip 20 passes through the groove 102 part, and this trend makes the local stress of the welding strip 20 also increase, which is easy to cause damage to the welding strip 20. Therefore, in the embodiment of the utility model, the radius R2 of the second curve can also satisfy the following expression: (R2+s) / h≥3.87. In the expression, R2+s is the sum of the piece spacing s between the adjacent two battery pieces 10 and the radius R2 of the groove 102, and the specific limitation is the size of the part of the welding strip 20 between the adjacent two battery pieces 10. It can be known from the above expression that when s and h are fixed, R2 is greater, and the above condition is more easily satisfied, that is, for the battery piece with a certain thickness and the battery string with a certain piece spacing, when R2 is greater, it is more beneficial to make the bending angle of the welding strip 20 smaller, and the bending part of the welding strip 20 tends to be smoother, thereby reducing the internal stress of the welding strip 20.
[0060] In some embodiments, for the battery piece 10 with a thickness h of 0.155 mm, the piece spacing s can be controlled to be not less than 0.6 mm, for example, s can be 0.61 mm, 0.62 mm, 0.63 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.67 mm, 0.68 mm, etc.
[0061] Optionally, referring to Figure 7 , the radius R1 of the first curve 1021a satisfies the following expression: R1=R2cosα / (1-cosα); wherein, α represents the included angle between the line connecting the center of the first curve 1021a and the center of the second curve 1022a and the main grid 101.
[0062] Specifically, in an embodiment, as Figure 7 shown, the line connecting the center of the first curve 1021a and the center of the second curve 1022a is a straight line L, and the included angle between the straight line L and the main grid 101 is α. Since the first curve 1021a is tangent to the second curve 1022a and the edge of the battery piece 10 at the same time, according to the geometric relationship, the radius R1 of the first curve 1021a satisfies the following expression: R1=R2cosα / (1-cosα).
[0063] Therefore, α and R1 have a one-to-one correspondence, and it is easy to understand from the figure that when α is smaller, R1 is also smaller, and the transition part of the groove 102 side wall and the battery piece 10 side wall is more prominent and the stress is more concentrated. When α is greater, R1 is also greater, and R1 is too large to easily cause the welding strip 20 to be unable to be constrained and positioned. Therefore, α can be an interval value that ensures that R1 satisfies the above requirement.
[0064] The application also provides a photovoltaic module comprising the cell sheet 10 of any of the above embodiments. The cell sheet 10 of the above embodiments is used to assemble and prepare the photovoltaic module, which can improve the yield of the photovoltaic module and the quality of the finished product while reducing the cell spacing to improve the power of the module.
[0065] It should be noted that, in this document, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, such that processes, methods, articles, or apparatuses that comprise a list of elements are not limited to those elements, but can also include other elements not expressly listed, or inherent to such processes, methods, articles, or apparatuses. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.
[0066] The embodiments of the application are described above in conjunction with the drawings, but the application is not limited to the specific embodiments described above, which are only illustrative and not restrictive, and those of ordinary skill in the art can make many forms under the inspiration of the application without departing from the purpose of the application and the scope protected by the claims.
Claims
1. A battery string, characterized in that, The battery string comprises battery pieces and welding bands, the front and back surfaces of the battery pieces are provided with electrical connection parts, the welding bands and the electrical connection parts are electrically connected to connect the battery pieces to form the battery string; At least one edge of the battery piece is provided with a groove corresponding to the welding band along the extension direction of the welding band, the groove penetrates the front and back surfaces of the battery piece; The opening of the groove faces the outside of the battery piece, the two side walls of the groove are first curved surfaces, and the two side walls of the groove are tangent to the side walls of the battery piece.
2. The battery string of claim 1, wherein, The electrical connection part is a main grid, at least one end of the main grid along the extension direction of the main grid and located at the edge of the battery piece is provided with a groove corresponding to the main grid.
3. The battery string of claim 1, wherein, The bottom between the two side walls of the groove is a second curved surface, and the two first curved surfaces are tangent to the second curved surface.
4. The battery string of claim 3, wherein, The projection of the groove along the thickness direction of the battery piece comprises a first curve formed by the first curved surface and a second curve formed by the second curved surface. The first curve and the second curve are both circular arcs, the radius of the first curve is R1, and the radius of the second curve is R2.
5. The battery string of claim 4, wherein, The welding band is embedded through the groove, and the welding band is in a flat state at the groove position.
6. The battery string of claim 5, wherein, The radius R2 of the second curve satisfies the following expression: R2 > πr 2 (2d); Wherein, r represents the radius of the welding band, and d represents the thickness of the welding band at the groove position.
7. The battery string of claim 6, wherein, 0.07mm≤d≤0.14mm.
8. The battery string of claim 6, wherein, The radius R2 of the second curve also satisfies the following expression: (R2+s) / h≥3.87; Wherein, h represents the thickness of the battery piece, and s represents the spacing between adjacent battery pieces along the string welding direction.
9. The battery string of claim 8, wherein, s>0.6mm.
10. A photovoltaic module, characterized by, The battery string comprises the battery string according to any one of claims 1 to 9.