Battery string and photovoltaic module

Abstract

The utility model relates to the field of photovoltaic technology, in particular to a battery string and a photovoltaic module, the battery string comprises at least two battery pieces which are welded in sequence, each battery piece comprises a first surface and a second surface which are opposite to each other, and a first gap is formed between every two adjacent battery pieces; the plurality of welding strips are connected to two adjacent battery pieces, the welding strips are respectively connected to the first surface of the first battery piece and the second surface of the second battery piece in the two adjacent battery pieces, and each welding strip comprises two end parts which are respectively connected with the first battery piece and the second battery piece and a middle part which is connected with the two end parts; the middle part extends into the first gap from the first surface of the first battery piece to the second surface of the second battery piece; a buffer layer provided in the intermediate portion; according to the mode, the buffer layer is arranged on the middle part of the welding strip, the buffer layer has a buffer effect on pressure borne by the edge part of the battery piece in the laminating process, hidden cracks of the edge of the battery piece in the laminating process are avoided, and the quality and the operation stability of a photovoltaic module are improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and particularly to a battery string and a photovoltaic module. Background Art

[0002] Currently, photovoltaic modules can convert the thermal radiation energy of the sun into electrical energy through the photovoltaic effect or the photochemical effect, and are applied to daily life and industrial production. When manufacturing a photovoltaic module, first, a welding tape is welded to the grid lines formed on the surface of a battery cell at a certain temperature by a string welding machine to obtain a battery string; then, a front panel, a front adhesive film, a battery pack composed of a plurality of battery strings, a back adhesive film, and a back panel are laminated and then laminated to obtain a photovoltaic module. Due to the continuous reduction of the distance between battery cells, during the lamination process, the edge portions of the battery cells near the gaps between the battery cells are prone to hidden cracks, which is not conducive to improving the quality and operation stability of the photovoltaic module. Summary of the Utility Model

[0003] In view of the above problems, embodiments of the present application provide a battery string and a photovoltaic module to solve the technical problem that the edges of the battery cells are prone to hidden cracks during the lamination process.

[0004] In a first aspect, an embodiment of the present application provides a battery string, including:

[0005] At least two sequentially welded battery cells, the battery cells including a first surface and a second surface opposite to the first surface, and a first gap is provided between two adjacent battery cells;

[0006] A plurality of welding tapes connecting two adjacent battery cells, the welding tapes are respectively connected to the first surface of the first battery cell and the second surface of the second battery cell among two adjacent battery cells, the welding tape includes two ends respectively connected to the first battery cell and the second battery cell and an intermediate portion connecting the two ends, and the intermediate portion extends from the first surface of the first battery cell into the first gap until the second surface of the second battery cell;

[0007] And a buffer layer provided on the intermediate portion.

[0008] Optionally, the intermediate portion includes a third surface and a fourth surface opposite to the third surface, and the buffer layer is laminated on the third surface and the fourth surface.

[0009] Optionally, the end portion includes a tapered section connected to the intermediate portion and a flat section connected to the tapered section, and the thickness of the flat section is greater than the thickness of the intermediate portion.

[0010] Optionally, the buffer layer extends from the tapered section at the first end to the middle portion and then to the tapered section at the second end.

[0011] Optionally, the sum of the thickness of the buffer layer and the middle portion is less than or equal to the thickness of the flat section.

[0012] Optionally, the buffer layer circumferentially wraps around the middle portion.

[0013] Optionally, the buffer layer is a polyethylene layer.

[0014] Optionally, the battery string further includes grid lines respectively disposed on the first surface and the second surface, and the solder tapes are respectively electrically connected to one of the grid lines on the first surface of the first battery cell and one of the grid lines on the second surface of the second battery cell among two adjacent battery cells.

[0015] In a second aspect, an embodiment of the present application provides a photovoltaic module, including the above-mentioned battery string.

[0016] Optionally, the photovoltaic module includes a first panel, a first encapsulant film, a battery group formed by a plurality of the battery strings, a second encapsulant film, and a second panel that are stacked in sequence.

[0017] The battery string and the photovoltaic module provided by the embodiments of the present application include at least two battery cells welded in sequence. The battery cells include a first surface and a second surface opposite to the first surface, and there is a first gap between two adjacent battery cells; a plurality of solder tapes connecting two adjacent battery cells, the solder tapes are respectively connected to the first surface of the first battery cell and the second surface of the second battery cell among two adjacent battery cells. The solder tape includes two ends respectively connected to the first battery cell and the second battery cell and a middle portion connecting the two ends. The middle portion extends from the first surface of the first battery cell into the first gap until the second surface of the second battery cell; and a buffer layer disposed on the middle portion; in the above manner, a buffer layer is provided on the middle portion of the solder tape, which has a buffering effect on the pressure received by the edge portion of the battery cell during the lamination process, avoiding the occurrence of hidden cracks at the edge of the battery cell during the lamination process, and improving the quality and operation stability of the photovoltaic module.

[0018] These aspects or other aspects of the present application will be more clearly understood in the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shows a schematic structural diagram of the battery string provided by the embodiment of the present application.

[0020] Figure 2 is Figure 1Schematic cross-sectional view along the A-A direction.

[0021] Figure 3 Schematic diagram showing the cooperation of the solder ribbon and the buffer layer in the battery string provided by the embodiment of the present application.

[0022] Figure 4 Schematic longitudinal cross-sectional view of the solder ribbon in the battery string provided by the embodiment of the present application.

[0023] Figure 5 Top view of the solder ribbon in the battery string provided by the embodiment of the present application.

[0024] Figure 6 Schematic longitudinal cross-sectional view of the solder ribbon in the battery string provided by the embodiment of the present application.

[0025] Figure 7 Schematic structural diagram of the battery string provided by the embodiment of the present application.

[0026] Figure 8 Schematic structural diagram of the battery string provided by the embodiment of the present application.

[0027] Figure 9 Schematic diagram showing the cooperation of the solder ribbon and the buffer layer in the battery string provided by the embodiment of the present application.

[0028] Figure 10 Schematic structural diagram of the battery string provided by the embodiment of the present application.

[0029] Figure 11 Schematic partial structural diagram of the photovoltaic module before lamination provided by the embodiment of the present application.

[0030] Figure 12 Schematic structural diagram of the photovoltaic module after lamination provided by the embodiment of the present application.

[0031] The meanings of the reference numerals in the drawings are as follows:

[0032] 100 - battery string; 10 - battery cell; 11 - first surface; 12 - second surface; 13 - first gap; 20 - solder ribbon; 21 - end; 211 - tapered section; 212 - flat section; 22 - middle part; 221 - third surface; 222 - fourth surface; 30 - buffer layer; 40 - grid line; 51 - first panel; 52 - second panel; 61 - first encapsulant film; 62 - second encapsulant film; 70 - battery pack; 80 - frame. Detailed implementation manners

[0033] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary only for explaining the present application and should not be construed as limiting the present application.

[0034] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application.

[0035] In the embodiments of the present application, it should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0036] Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0037] In the description of the embodiments of the present application, words such as "example" or "for example" are used to indicate exemplification, illustration or description. Any embodiment or design solution described as "for example" or "for instance" in the embodiments of the present application is not construed as being more preferred or having more advantages than another embodiment or design solution. The use of words such as "example" or "for example" is intended to present relative concepts in a clear manner.

[0038] In addition, "a plurality of" in the embodiments of the present application means two or more. In view of this, "a plurality of" in the embodiments of the present application can also be understood as "at least two". "At least one" can be understood as one or more, for example, understood as one, two or more. For example, including at least one means including one, two or more, and does not limit which ones are included. For example, including at least one of A, B and C, then the ones included can be A, B, C, A and B, A and C, B and C, or A and B and C.

[0039] It should be noted that in the embodiments of the present application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / ", unless otherwise specified, generally represents an "or" relationship between the front and rear associated objects.

[0040] An embodiment of the present application provides a battery string 100. Please refer to Figures 1 to 3 As shown, the battery string 100 of this embodiment includes solar cells 10, solder tapes 20, and a buffer layer 30.

[0041] Among them, at least two solar cells 10 are provided, and the at least two solar cells 10 are sequentially welded. The solar cell 10 includes a first surface 11 and a second surface 12, and the first surface 11 and the second surface 12 are oppositely arranged. Exemplarily, the first surface 11 and the second surface 12 can be the front and back surfaces of the solar cell respectively, or the first surface 11 and the second surface 12 can be the back and front surfaces of the solar cell respectively.

[0042] Among them, the at least two solar cells 10 are sequentially arranged, and there is a first gap 13 between two adjacent solar cells 10.

[0043] Among them, the solder tape 20 is connected to every two adjacent solar cells 10, and the solder tape 20 is respectively connected to the first surface 11 of the first solar cell 10 and the second surface 12 of the second solar cell 10 among two adjacent solar cells 10. During string soldering, the solder tape 20 extends from the first surface 11 of the first solar cell 10 to the first gap 13, and after passing through the first gap 13, it extends to the second surface 12 of the second solar cell 10.

[0044] Among them, please refer to Figure 2 and Figure 3 As shown, the solder tape 20 includes two end portions 21 respectively connected to the first solar cell 10 and the second solar cell 10 and an intermediate portion 22 connecting the two end portions 21. The intermediate portion 22 extends from the first surface 11 of the first solar cell 10 into the first gap 13 until the second surface 12 of the second solar cell 10.

[0045] Among them, the buffer layer 30 is provided on the intermediate portion 22. The buffer layer 30 directly receives the pressure transmitted from the intermediate portion 22 to the edge of the solar cell 10 during the lamination process and buffers the pressure. The pressure transmitted from the buffer layer 30 to the edge portion of the solar cell 10 is greatly reduced.

[0046] In this embodiment, a buffer layer is provided on the intermediate portion of the solder tape, which has a buffering effect on the pressure received by the edge portion of the solar cell during the lamination process, avoiding the occurrence of hidden cracks at the edge of the solar cell during the lamination process, and improving the quality and operation stability of the photovoltaic module.

[0047] Exemplarily, the structure of the battery string of this embodiment is particularly applicable to application scenarios where the first gap 13 is a small pitch. For example, the width of the first gap 13 can be 0.5 mm to 1.0 mm; the structure of the battery string of this embodiment is also applicable to application scenarios where the first gap 13 is not a small pitch. For example, the width of the first gap 13 can also be 1.5 mm to 2.0 mm.

[0048] As an implementation manner, please refer to Figure 4 As shown, the middle part 22 includes a third surface 221 and a fourth surface 222 opposite to the third surface 221, and the buffer layer 30 is laminated on the third surface 221 and the fourth surface 222. In this implementation manner, the middle part 22 is flat before welding, and the third surface 221 and the fourth surface 222 can be substantially parallel to the first surface 11 and the second surface 12 of the battery cell 10 respectively. The flat middle part 22 is beneficial to increasing the stress area at the edge of the battery cell 10 during lamination, and is beneficial to further avoiding the occurrence of hidden cracks at the edge of the battery cell 10 corresponding to the middle part 22 of the welding tape 20 during the lamination process.

[0049] In some implementation manners, please refer to Figure 4 and Figure 5 As shown, the end part 21 includes a tapered section 211 connected to the middle part 22 and a flat section 212 connected to the tapered section 211, and the thickness of the flat section 212 is greater than the thickness of the middle part 22.

[0050] In some implementation manners, the buffer layer 30 can also cover the tapered section 211 at the same time. Please refer to Figure 6 As shown, the buffer layer 30 extends from the tapered section 211 of the first end part 21 to the middle part 22 until the tapered section 211 of the second end part 21. In this implementation manner, the buffer layer extends from the middle part to both sides to the two tapered sections, increasing the setting area of the buffer layer, and can further avoid the occurrence of hidden cracks at the edge positions of the battery cell in contact with the two tapered sections during the lamination process.

[0051] In some implementation manners, please continue to refer to Figure 6 As shown, the sum h5 of the thickness of the buffer layer 30 and the middle part 22 is less than or equal to the thickness h6 of the flat section 212. In this implementation manner, the total thickness of the middle part after the buffer layer is provided is less than or equal to the thickness of the flat section, which is beneficial to reducing the pressure of the middle part on the edge of the battery cell, and further avoiding the occurrence of hidden cracks at the edge of the battery cell corresponding to the middle part of the welding tape during the lamination process.

[0052] In some implementation manners, please refer to Figure 5 As shown, the width h1 of the middle part 22 is greater than the width h2 of the flat section 212.

[0053] Exemplarily, as Figure 5As shown, before welding, the third surface 221 and the fourth surface 222 can be flat surfaces respectively, and the states of the third surface 221 and the fourth surface 222 before welding can be parallel to the first surface 11 and the second surface 12 of the cell 10 respectively. The contact surface of the buffer layer 30 with the middle part 22 and the side facing away from the middle part 22 can be flat surfaces respectively; Exemplarily, please refer to Figure 7 As shown, before welding, the third surface 221 and the fourth surface 222 can also be arc-shaped surfaces that are recessed inward. At this time, the thicknesses of different positions of the middle part 22 along the length direction are different, and the thicknesses of the flat sections 212 are greater than the thicknesses of different positions of the middle part 22 respectively. The contact surface of the buffer layer 30 with the middle part 22 can be an arc-shaped convex surface adapted to the third surface 221 and the fourth surface 222, and the side of the buffer layer 30 facing away from the middle part 22 is a flat surface.

[0054] In some embodiments, please refer to Figure 5 and Figure 7 As shown, when performing series welding, the welding ribbon 20 extends along its length direction, and the welding ribbon 20 is parallel to the cell 10.

[0055] In some embodiments, please refer to Figure 8 As shown, when performing series welding, the welding ribbon 20 bends and extends from the first surface 11 of the first cell 10 to the first gap 13, and after passing through the first gap 13, it bends and extends to the second surface 12 of the second cell 10. In this embodiment, the two end portions 21 are not bent before and during welding, and the middle part 22 is the part that forms two bends during series welding. It is prone to deformation during lamination. If the edge of the cell 10 corresponding to the middle part 22 directly receives the pressure transmitted by the welding ribbon during the lamination process of the subsequent photovoltaic module manufacturing, hidden cracks are likely to occur. Through the setting of the buffer layer 30, the buffer layer 30 is closely attached to the cell 10, avoiding the deformation of the welding ribbon during lamination, and buffering the pressure transmitted from the middle part 22 to the edge of the cell 10, avoiding hidden cracks in the cell.

[0056] In some embodiments, please refer to Figure 3 As shown, the thickness h3 of the buffer layer 30 is less than 0.1 mm.

[0057] In some embodiments, please refer to Figure 3 As shown, the width h4 of the buffer layer 30 is less than 0.2 mm.

[0058] As an embodiment, please refer to Figure 9 As shown, the buffer layer 30 is wrapped around the middle part 22 along the circumferential direction of the middle part 22. In this embodiment, the buffer layer 30 is directly wrapped around the outer periphery of the middle part 22 without processing the middle part into a flat shape, which is beneficial to simplifying the processing steps of the welding ribbon.

[0059] As an implementation manner, the buffer layer 30 can be made of a glue-like material that has a certain elasticity after forming to increase the buffering effect. For example, the buffer layer 30 is a polyethylene layer.

[0060] In some implementation manners, the buffer layer 30 can be made of the same material as the glue film laminated on the battery string during the production of the photovoltaic module. After lamination, the buffer layer 30 and the glue film can be better fused, reducing the influence degree of the buffer layer setting on the performance of the photovoltaic module, and at the same time, being beneficial to reducing the influence degree of the buffer layer setting on the appearance of the photovoltaic module.

[0061] Exemplarily, the buffer layer 30 can be made of EVA (Ethylene Vinyl Acetate Copolymer), EPE (Expanded Polyethylene), or POE (Polyolefin Elastomer).

[0062] As an implementation manner, please refer to Figure 10 As shown, the battery string 100 further includes grid lines 40 respectively disposed on the first surface 11 and the second surface 12. The solder tapes 20 are respectively electrically connected to one of the grid lines 40 on the first surface 11 of the first battery cell 10 and one of the grid lines 40 on the second surface 12 of the second battery cell 10 among two adjacent battery cells 10. In this implementation manner, the solder tapes 20 are respectively welded to the two grid lines 40 through their ends 21. Since the solder tapes 20 and the grid lines 40 are respectively conductive, the electrical connection of two adjacent battery cells 10 can be realized by welding the solder tapes 20 to the grid lines 40.

[0063] In some implementation manners, the length of the grid line 40 is the same as the length of the end 21.

[0064] In some implementation manners, multiple grid lines 40 on the first surface 11 of the battery cell 10 are respectively positive grid lines, multiple grid lines 40 on the first surface 11 of the battery cell 10 are respectively negative grid lines, and the solder tapes 20 are respectively connected to any positive grid line of the first battery cell 10 and the corresponding negative grid line of the second battery cell 10 among two adjacent battery cells 10. In this implementation manner, the solder tapes connect the positive grid lines and the negative grid lines of two adjacent battery cells to connect the battery cells in series in sequence. The power of the battery string is determined by the number of series-connected battery cells and the power of a single battery cell.

[0065] In some implementation manners, the grid line 40 can be a main grid line. The increase in the number of main grid lines can reduce the resistance of the battery string. The distance between adjacent main grid lines is shortened, the current conduction path becomes shorter, and the current conduction loss is reduced.

[0066] As an implementation manner, the battery string can be a battery string without a main grid, and the grid line 40 can be a sub-grid line. Adopting the design without a main grid can extend the battery life.

[0067] Exemplarily, the setting manner of the buffer layer in this embodiment can be applied to all battery string structures with solder tapes. For example, it can be adapted to TOPCon (Tunnel Oxide Passivated Contact) batteries, HJT (Heterojunction with Intrinsic Thin-film) batteries, and IBC (Interdigitated Back Contact) batteries in the background art.

[0068] As an implementation manner, the battery cell 10 can be a whole battery cell.

[0069] As an implementation manner, the battery cell 10 can be a half battery cell. For example, the half battery cell can be prepared by cutting a single-crystalline silicon crystal, which can reduce material waste and thus reduce the manufacturing cost.

[0070] As an implementation manner, the battery cell 10 can be a battery cell of any size. For example, the battery cell can also be prepared by cutting a single-crystalline silicon crystal into any size, which can reduce material waste and thus reduce the manufacturing cost.

[0071] An embodiment of the present application provides a photovoltaic module, which includes the battery string 100 of any of the above embodiments or implementation manners.

[0072] In this embodiment, when manufacturing the battery string, a buffer layer is provided on the middle part of the solder tape, which has a buffering effect on the pressure received by the edge of the battery cell corresponding to the middle part of the solder tape during the lamination process, avoiding the occurrence of hidden cracks at the edge of the battery cell during the lamination process, and improving the quality and operation stability of the photovoltaic module.

[0073] As an implementation manner, please refer to Figure 11 and Figure 12 As shown, the photovoltaic module includes a first panel 51, a first encapsulant film 61, a battery pack 70, a second encapsulant film 62, and a second panel 52 that are stacked in sequence.

[0074] Among them, the battery pack 70 includes a plurality of battery strings 100. The battery pack 70 can be formed by connecting a plurality of battery strings 100 in series and / or in parallel.

[0075] As an implementation manner, the first panel 51 and the second panel 52 can be photovoltaic glasses respectively.

[0076] As an implementation manner, the first adhesive film 61 and the second adhesive film 62 can be EVA (Ethylene Vinyl Acetate Copolymer), EPE (Expanded Polyethylene), or POE (Polyolefin Elastomer) respectively.

[0077] In some implementation manners, the buffer layer 30 can be made of the same material as the first adhesive film 61 and the second adhesive film 62. After lamination, the buffer layer 30 can be better integrated with the first adhesive film 61 and the second adhesive film 62, reducing the influence degree of the buffer layer setting on the performance of the photovoltaic module, and at the same time being beneficial to reducing the influence degree of the buffer layer setting on the appearance of the photovoltaic module.

[0078] In some implementation manners, please refer to Figure 12 As shown, the photovoltaic module further includes a frame 80.

[0079] As an implementation manner, the photovoltaic module can be prepared in the following way:

[0080] S21, after obtaining a battery string by series soldering, perform an EL (Electroluminescent) test on it to obtain a broken grid result;

[0081] S22, use a lamination method to sequentially lay a first panel, a first adhesive film, a battery group formed by battery strings, a second adhesive film, and a second panel to obtain a photovoltaic encapsulation structure;

[0082] S23, connect and fix the lead-out wires of the solder tapes at both ends of the battery group to a bus bar;

[0083] S24, sequentially laminate, install a frame, apply glue, and cure the photovoltaic encapsulation structure to obtain a photovoltaic module, and test for hidden cracks after lamination;

[0084] S25, perform a hot spot durability test on the photovoltaic module.

[0085] The above are only the implementation manners of the present application. It should be noted here that for those of ordinary skill in the art, improvements can be made without departing from the creative concept of the present application, but these all belong to the protection scope of the present application.

Claims

1. A battery string, characterized in that: include: At least two battery cells welded in sequence, wherein the battery cell comprises a first surface and a second surface opposite to the first surface, and a first gap is formed between two adjacent battery cells; A plurality of welding strips connected to two adjacent battery cells, wherein the welding strips are respectively connected to a first surface of a first battery cell and a second surface of a second battery cell of the two adjacent battery cells, wherein the welding strips include two ends respectively connected to the first battery cell and the second battery cell and a middle portion connecting the two ends, wherein the middle portion extends from the first surface of the first battery cell to the first gap and to the second surface of the second battery cell; And, a buffer layer is arranged in the middle portion.

2. The battery string according to claim 1, characterized in that: The middle portion includes a third surface and a fourth surface opposite to the third surface, and the buffer layer is stacked on the third surface and the fourth surface.

3. The battery string according to claim 2, characterized in that: The end portion includes a gradient section connected to the middle portion and a flat section connected to the gradient section, and a thickness of the flat section is greater than a thickness of the middle portion.

4. The battery string according to claim 3, characterized in that: The buffer layer extends from the transition section at the first end portion to the middle portion and to the transition section at the second end portion.

5. The battery string according to claim 3, characterized in that: The sum of the thickness of the buffer layer and the middle portion is less than or equal to the thickness of the flattening section.

6. The battery string according to claim 1, characterized in that: The buffer layer covers the middle portion along a circumferential direction of the middle portion.

7. The battery string according to claim 1, characterized in that: The buffer layer is a polyethylene layer.

8. The battery string according to claim 1, characterized in that: The battery string also includes grid lines respectively arranged on the first surface and the second surface, and the welding strip is respectively electrically connected to one of the grid lines on the first surface of the first battery cell and one of the grid lines on the second surface of the second battery cell of two adjacent battery cells.

9. A photovoltaic module, characterized in that: The invention comprises a battery string as claimed in any one of claims 1 to 8.

10. The photovoltaic module according to claim 9, characterized in that: The photovoltaic module comprises a first panel, a first adhesive film, a battery group formed by a plurality of battery strings, a second adhesive film and a second panel which are stacked in sequence.

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