Solar cell module and photovoltaic system

Abstract

The utility model discloses a solar cell module and a photovoltaic system, the solar cell module comprises a cell string, the cell string comprises a plurality of cell sheets arranged along a first direction, two adjacent cell sheets are electrically connected through a solder strip, the solder strip comprises a first solder strip and a second solder strip, and the first solder strip and the second solder strip are electrically connected. The first welding strips and the second welding strips are alternately arranged at intervals in the second direction. The bus bar is at least arranged on one battery piece in the second direction, the bus bar comprises a bus part and a non-bus part, the bus part is electrically connected with the first welding strip, and the non-bus part is at least arranged on the second welding strip; and a through hole is formed in the non-bus-bar part of the bus bar. By adopting the solar cell module provided by the utility model, the welding stress generated when the bus bar is welded with the cell piece can be reduced, so that the hidden crack and fragment risks of the cell piece in the process of forming the solar cell module are reduced.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, and in particular to a solar cell module and photovoltaic system. Background Technology

[0002] Multiple back-contact solar cells undergo string welding, lamination, and encapsulation to form a solar cell module. This module includes a cell string assembly and busbars for connecting the string assemblies in parallel. The busbars are connected to the cell string assembly by welding. Due to the difference in thermal expansion coefficients between the busbars and the back-contact solar cells, the welding stress is high, resulting in severe warping of the back-contact solar cells after welding. This also increases the risk of microcracks and cell breakage in the laminated solar cell module. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a solar cell module and photovoltaic system that reduces the welding stress of the busbar and the cell, thereby reducing the warping of the cell.

[0004] To address the aforementioned technical problems, this utility model provides a solar cell module, comprising:

[0005] A battery string, the battery string comprising a plurality of battery cells arranged along a first direction, two adjacent battery cells being electrically connected by a solder strip, the solder strip comprising a first solder strip and a second solder strip, the first solder strip and the second solder strip being arranged alternately and at intervals along a second direction;

[0006] A busbar is provided on at least one of the battery cells along a second direction. The busbar includes a busbar portion and a non-busbar portion. The busbar portion is electrically connected to the first welding strip, and the non-busbar portion is provided on at least the second welding strip. The non-busbar portion of the busbar is provided with a through hole.

[0007] As an improvement to the above solution, the second welding strip is provided with an insulating layer on the side opposite to the battery cell, the non-current converging part is insulated from the second welding strip through the insulating layer, and the through hole is provided in the area where the non-current converging part and the insulating layer contact.

[0008] As an improvement to the above solution, the through hole is located in the area where the non-confluence portion overlaps with the second solder strip.

[0009] As an improvement to the above scheme, along the second direction, the length of the through hole is D1, and the width of the second welding strip is D2. D1 and D2 satisfy the following relationship: D1 = (0.1~0.9)D2.

[0010] As an improvement to the above solution, the through holes are spaced apart on the busbar along the second direction.

[0011] As an improvement to the above solution, the through holes are evenly spaced along the second direction on the busbar.

[0012] As an improvement to the above solution, along the second direction, the distance between two adjacent through holes is equal to the distance between two adjacent second weld strips.

[0013] As an improvement to the above scheme, along the first direction, the width of the through hole is D3, and the width of the busbar is D4. D3 and D4 satisfy the following relationship: D3 = (0.1~0.9)D4.

[0014] As an improvement to the above scheme, along the first direction, the minimum distance between the edge of the through hole and the edge of the busbar is D5, and D5 and D4 satisfy the following relationship: D5 = (0.1~0.45)D4.

[0015] As an improvement to the above scheme, D1 is 0.5mm to 12mm, and D3 is 0.5mm to 12mm.

[0016] As an improvement to the above solution, the through hole can be circular or polygonal in shape.

[0017] Accordingly, this utility model also provides a photovoltaic system, including the aforementioned solar cell module.

[0018] Implementing this utility model has the following beneficial effects:

[0019] This invention releases stress concentration caused by welding the busbar to the battery cell by designing through holes in the busbar, and reduces problems such as battery cell warping caused by welding stress through the stress-reducing design of the busbar. In addition, the through holes are not located on the busbar section where the busbar and the welding strip are electrically connected, which reduces welding stress while ensuring the reliability of the connection between the busbar and the welding strip. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a solar cell module provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a solar cell module provided in another embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. In the description of this application, it should be understood that the terms "length," "width," "upper," "lower," "left," "right," "horizontal," "top," and "bottom," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] like Figure 1 As shown, this embodiment of the present invention provides a solar cell module, including a cell string 1 and a busbar 2. The cell string 1 includes multiple cell sheets 11 arranged along a first direction. Adjacent cell sheets 11 are electrically connected by solder strips 12. The solder strips 12 include a first solder strip 121 and a second solder strip 122, which are arranged alternately along a second direction. The busbar 2 is disposed on at least one cell sheet 11 along the second direction. The busbar 2 includes a current-collecting part 21 and a non-current-collecting part 22. The current-collecting part 21 is electrically connected to the first solder strip 121, and the non-current-collecting part 22 is disposed on at least the second solder strip 122. The non-current-collecting part 22 of the busbar 2 is provided with a through hole 23. The through hole 23 serves as a stress-reducing hole to release welding stress and avoid problems such as severe warping of the cell sheets 11, microcracks in the laminated solar cell module, and cell breakage caused by welding stress. Furthermore, placing the through-hole 23 on the non-busbar section 22 avoids the reduction in the electrical connection area between the busbar 2 and the first solder strip 121 caused by placing the through-hole 23 on the busbar section 21. This results in high reliability of the connection between the busbar 2 and the first solder strip 121 and good current collection and discharge effect. In addition, the through-hole 23 can also reduce the amount of material used in the busbar 2 itself, thereby saving costs.

[0024] like Figure 2As shown, in a preferred embodiment, the side of the second solder strip 122 facing away from the battery cell 11 is provided with an insulating layer 3. The non-current-collecting portion 22 is insulated from the second solder strip 122 through the insulating layer 3, thereby realizing the electrical connection between the busbar 2 and the first solder strip 121 and the insulation between the busbar 2 and the second solder strip 122. The insulating layer 3 is disposed between the second solder strip 122 and the non-current-collecting portion 22 of the busbar 2, which enables the solder strip to be completely attached to the electrode area, ensuring that the solder strip is connected to a sufficient number of fine grids, making full use of each fine grid, better collecting current, and improving the current collection effect of the solder strip. It is understood that the width of the insulating layer 3 in the first direction must be at least greater than the width of the busbar 2 in the first direction to prevent the busbar 2 from contacting the second solder strip 122 or the electrode area collected by the second solder strip 122 and causing a short circuit. It is understood that the through hole 23 is disposed on the non-current-collecting portion 22 of the busbar 2, that is, it can be disposed in the part of the busbar 2 that is in contact with the area without solder strip, that is, the area between the first solder strip 121 and the second solder strip 122. Preferably, the through hole 23 is located in the area where the non-current collector 22 and the insulating layer 3 contact, which can also relieve the stress during the welding process of the second welding strip 122 and further improve the overall quality of the battery cell 11.

[0025] More preferably, the through hole 23 is located in the area where the non-current confluence section 22 overlaps with the second solder strip 122. Positioning the through hole 23 in the area where the non-current confluence section 22 overlaps with the second solder strip 122 can effectively alleviate stress concentration caused by thermal stress during the welding of the second solder strip 122 to the battery cell 11.

[0026] Specifically, along the second direction, the length of the through hole is D1, and the width of the second weld strip 122 is D2. D1 and D2 satisfy the following relationship: D1 = (0.1~0.9)D2. If the ratio of D1 to D2 is too large or too small, it will be difficult to achieve a good stress relief effect. Preferably, D1 = (0.6~0.8)D2.

[0027] In a preferred embodiment, through holes 23 are spaced apart on the busbar 2 along the second direction. The spaced through holes 23 improve the overall stress relief effect of the busbar 2. More preferably, the through holes 23 are uniformly spaced apart on the busbar 2 along the second direction. Uniformly spaced through holes 23 can release welding stress more evenly, thereby improving the quality of the solar cell module.

[0028] In a preferred embodiment, along the second direction, the distance between two adjacent through holes 23 is equal to the distance between two adjacent second weld strips 122. That is, through holes 23 are provided in the area where the busbar 2 contacts each second weld strip 122, thereby better realizing stress release of each part of the busbar 2.

[0029] To improve stress relief while ensuring the quality of the busbar 2, the width of the through hole 23 is D3 along the first direction, and the width of the busbar 2 is D4. D3 and D4 satisfy the following relationship: D3 = (0.1~0.9)D4. If D3 < 0.1D4, the through hole 23 has little effect on stress relief; if D3 > 0.9D4, it will affect the strength of the busbar 2, increasing the possibility of breakage. Preferably, D3 = (0.3~0.5)D4.

[0030] Preferably, along the first direction, the minimum distance between the edge of the through hole 23 and the edge of the busbar 2 is D5, and D5 and D4 satisfy the following relationship: D5 = (0.1~0.45)D4. Maintaining a certain distance between the edge of the through hole 23 and the edge of the busbar 2 avoids the possibility of a decrease in the strength of one or both sides of the busbar 2 due to the distance between the through hole 23 and the edge of the busbar 2 being too small.

[0031] Optionally, the through-hole 23 can be circular or polygonal. The polygon can be triangular, rectangular, pentagonal, hexagonal, etc., but is not limited to these. Preferably, the through-hole 23 is circular. Due to geometric symmetry, a circular through-hole 23 can distribute stress more evenly around itself, reducing stress concentration peaks and thus achieving more effective stress release. Furthermore, the busbar 2 can be rectangular, meaning both its front and back sides are rectangular. Preferably, the busbar 2 can be a strip-shaped busbar, which can effectively collect and conduct current. Specifically, along the second direction, the length D1 of the through-hole is 0.5mm to 12mm, and along the first direction, the width D3 of the through-hole 23 is 0.5mm to 12mm. More preferably, the through-hole is a circle with a diameter of 0.5mm to 12mm. For example, the diameter of the through-hole 23 is 1mm, 2mm, 5mm, 7mm, or 10mm, but is not limited to these.

[0032] In the process of forming a solar cell module, a first solder ribbon 121 and a second solder ribbon 122 are placed on the electrode regions of two cells 11 arranged along a first direction. A busbar 2 is placed on the back side of at least one cell 11, and the busbar 2 is in electrical contact with the first solder ribbon 121 and insulated from the second solder ribbon 122. It is understood that the first solder ribbon 121 and the second solder ribbon 122 can be placed and positioned on the electrode regions, and the busbar 2 is also placed and positioned on the first solder ribbon 121 and the second solder ribbon 122. That is, in this step, the solder ribbons are not welded to the electrode regions, and the busbar is not welded to the solder ribbons. Subsequently, through lamination, the first solder ribbon 121 and the second solder ribbon 122 are welded to the electrode regions, and the busbar 2 is welded to the first solder ribbon 121. The through-hole 23 can reduce cell warping caused by thermal stress between the busbar 2 and the cell 11 during lamination welding, and can also reduce thermal stress between the solder ribbon and the cell 11.

[0033] In a preferred embodiment, the busbar 2 and the first solder strip 121 can be assembled and then placed onto the battery cell 11. Specifically, the second solder strip 122 is placed in the electrode region of the two overlapping battery cells 11, and the assembly of the first solder strip 121 and the busbar 2 is placed onto the battery cell 11, so that the first solder strip 121 is located in the corresponding electrode region. In this way, the first solder strip 121 and the intermediate busbar 2 are pre-assembled before lamination, avoiding the risk of microcracks or breakage that would occur if the first solder strip 121 and the busbar 2 were directly welded together on the battery cell 11. The through-hole 23 can alleviate stress concentration caused by welding.

[0034] It is understood that a solar cell module includes a first cover plate, a first encapsulating film, at least one cell string 1, a second encapsulating film, and a second cover plate stacked sequentially. Specifically, the first cover plate is typically made of a material with high light transmittance and strong weather resistance, including but not limited to glass and polycarbonate. Its main function is to protect the sensitive components inside the cell module from external environmental damage, while providing necessary mechanical support to ensure the structural integrity of the cell module. The first encapsulating film is located between the first cover plate and the cell string, primarily serving an adhesive and sealing function to ensure that the cell module does not experience delamination or leakage during long-term use. The materials of the first encapsulating film include, but are not limited to, ethylene-vinyl acetate copolymer (EVA) and polyolefin (POE). The second encapsulating film is located between the cell string and the second cover plate, serving a similar function to the first encapsulating film, primarily serving an adhesive and sealing function. The second cover plate is typically made of a material with strong weather resistance, including but not limited to aluminum plates and backsheet films. Its main function is to protect the back of the cell module from external environmental influences, provide additional mechanical support, and also act as an insulating layer for the cell module, ensuring safe use.

[0035] Each battery string comprises multiple battery cells connected in series. These cells can be partially overlapped to form the battery string. The contact areas between these overlaps are not electrically connected; that is, no conductive adhesive or other bonding agent is needed between the overlapping areas. The cells are simply overlapped. Optionally, the battery cells can be electrically connected as a single piece or in multiple segments. The overlapping areas of adjacent battery cells within the battery string are provided with series solder strips to securely connect adjacent cells, and these series solder strips connect adjacent battery cells in series. Different battery strings are obtained through series and / or parallel connections.

[0036] The battery module is formed by sequentially laying a first cover plate, a first adhesive film, several battery strings, a second adhesive film, and a second cover plate, followed by lamination. The lamination process includes preheating, pressurized heating, and cooling curing, the purpose of which is to tightly bond the multiple layers of module materials under high temperature and high pressure to form a single integrated structure.

[0037] Accordingly, this utility model embodiment also provides a photovoltaic system. It is understood that the photovoltaic system includes at least one solar cell module as described above. It is also understood that the solar cell modules can be electrically connected in parallel or in series, depending on actual needs. The photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy for power generation, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy for power generation. Taking a photovoltaic power generation system grid as an example, the photovoltaic system can include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array can be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0038] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A solar cell module, characterized in that, include: A battery string, the battery string comprising a plurality of battery cells arranged along a first direction, two adjacent battery cells being electrically connected by a solder strip, the solder strip comprising a first solder strip and a second solder strip, the first solder strip and the second solder strip being arranged alternately and at intervals along a second direction; A busbar is provided on at least one of the battery cells along a second direction. The busbar includes a busbar portion and a non-busbar portion. The busbar portion is electrically connected to the first welding strip, and the non-busbar portion is provided on at least the second welding strip. The non-busbar portion of the busbar is provided with a through hole.

2. The solar cell module as described in claim 1, characterized in that, The second welding strip has an insulating layer on the side opposite to the battery cell. The non-current converging portion is insulated from the second welding strip through the insulating layer. The through hole is located in the area where the non-current converging portion and the insulating layer contact.

3. The solar cell module as described in claim 2, characterized in that, The through hole is located in the area where the non-merging part overlaps with the second solder strip.

4. The solar cell module as described in claim 2, characterized in that, Along the second direction, the length of the through hole is D1, and the width of the second weld strip is D2, where D1 and D2 satisfy the following relationship: D1 = (0.1 ~ 0.9)D2.

5. The solar cell module as described in claim 1, characterized in that, The through holes are spaced apart on the busbar along the second direction.

6. The solar cell module as described in claim 5, characterized in that, The through holes are evenly spaced along the second direction on the busbar.

7. The solar cell module as described in claim 6, characterized in that, Along the second direction, the distance between two adjacent through holes is equal to the distance between two adjacent second weld strips.

8. The solar cell module as described in claim 4, characterized in that, Along the first direction, the width of the through hole is D3, and the width of the busbar is D4. D3 and D4 satisfy the following relationship: D3 = (0.1 ~ 0.9)D4.

9. The solar cell module as described in claim 8, characterized in that, Along the first direction, the minimum distance between the edge of the through hole and the edge of the busbar is D5, and D5 and D4 satisfy the following relationship: D5 = (0.1~0.45)D4.

10. The solar cell module as described in claim 8, characterized in that, The diameter of D1 is 0.5mm to 12mm, and the diameter of D3 is 0.5mm to 12mm.

11. The solar cell module as claimed in claim 1, characterized in that, The through hole is circular or polygonal in shape.

12. A photovoltaic system, characterized in that, Includes the solar cell module as described in any one of claims 1 to 11.

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