A battery string and method of making the same, a battery assembly, and a photovoltaic system

Abstract

This invention discloses a battery string, its fabrication method, a battery module, and a photovoltaic system. The battery string includes: multiple battery cells; the multiple battery cells are sequentially connected along a first direction; an assembly structure is located on one side of the multiple battery cells sequentially connected along the first direction; the assembly structure includes: solder ribbons extending along the first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder ribbons away from the battery cells; the assembly structure also has multiple cut-hole regions; along the first direction, the distance between the center of each cut-hole region and the intersection point of the centerline of two adjacent edges of adjacent battery cells along the second direction and the extension line of the solder ribbon is less than or equal to 5 mm; the cut-hole regions penetrate the corresponding thin film layer and solder ribbons; the first direction and the second direction are perpendicular. The technical solution of this invention can reduce manufacturing costs, enhance the reliability of the battery string, and improve the overall competitiveness of the product.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a battery string and its preparation method, battery module and photovoltaic system. Background Technology

[0002] Solar cells are used to directly convert sunlight into electrical energy. With the continuous development of photovoltaic technology, solar cell products, as semiconductor devices that convert solar energy into electrical energy, have been rapidly developed. Currently, in the photovoltaic cell welding process, to improve the bifacial power generation efficiency of the cell, a coating welding process is commonly used. In this process, before the lamination process, the solder ribbon is mechanically pressed and pre-attached to the surface of the cell using a coating material. Then, in the lamination process, the solder ribbon and the cell are welded and cured under high temperature and high pressure, simultaneously achieving the bonding of the coating with the cell and the solder ribbon.

[0003] In order to maximize the light-receiving area on the back of the battery and reduce power generation loss caused by shading, existing technologies generally use round wire soldering ribbons with a sufficiently small diameter. The battery cells are designed without main grids, solder pads, and pre-printed solder paste. In addition, adhesive is not used to fix the soldering ribbons to avoid occlusion by the adhesive, and the amount of insulating adhesive is minimized.

[0004] However, existing processes require high precision in the placement of the solder strips. The shortened solder strips are prone to bending and disturbance, and they are also prone to misalignment during the lamination and thermosetting process. This can result in insufficient contact area or misalignment between the solder strip and the cell, leading to incomplete soldering or short circuits. Furthermore, if the solder strips are misaligned, the high pressure during lamination welding can cause uneven stress concentration in the cell, resulting in cell breakage or microcracks. This increases manufacturing costs, reduces reliability, and affects the overall competitiveness of the product. Summary of the Invention

[0005] This invention provides a battery string and its preparation method, a battery module and a photovoltaic system, to reduce manufacturing costs, enhance the reliability of the battery string and improve the overall competitiveness of the product.

[0006] According to one aspect of the present invention, a battery string is provided, the battery string comprising: Multiple solar cells; the multiple solar cells are connected sequentially along a first direction; The composite structure is located on one side of a plurality of battery cells connected sequentially along a first direction; the composite structure includes: solder ribbons extending along the first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder ribbons away from the battery cells; the composite structure is also provided with a plurality of cut-hole areas; along the first direction, the distance between the center of the cut-hole area and the intersection point of the center line of two adjacent edges of the adjacent battery cell along the second direction and the extension line of the solder ribbon is less than or equal to 5 mm; the cut-hole area penetrates the corresponding thin film layer and solder ribbon; the first direction and the second direction are perpendicular.

[0007] Optionally, along the second direction, multiple cutting hole areas are located on the same first horizontal line, or on a second horizontal line parallel to the first horizontal line; Along the first direction, the first horizontal line and the second horizontal line are set alternately.

[0008] Optionally, along the second direction, the spacing between cut-hole areas located on the same first horizontal line or the same second horizontal line is an even multiple of the spacing between adjacent weld strips.

[0009] Optionally, along the second direction, the spacing between the cut-hole area on the first horizontal line and the cut-hole area on the second horizontal line is an odd multiple of the spacing between adjacent solder strips.

[0010] Optionally, the cut-hole area located on the first horizontal line and the cut-hole area located on the second horizontal line are both disposed on the same thin film layer.

[0011] Optionally, along the second direction, the width of the cut-hole area is greater than the width of the solder strip and less than the spacing between adjacent solder strips.

[0012] Optionally, along the third direction, the thickness of the thin film layer is greater than or equal to 50 micrometers and less than or equal to 300 micrometers; the third direction is perpendicular to both the first and second directions.

[0013] Optionally, the battery string may also include: an adhesive layer; the adhesive layer is located between the solder strip and the thin film layer; And / or, The adhesive layer is located between the solar cell and the thin film layer.

[0014] Optionally, along a third direction, the thickness of the adhesive layer is less than the thickness of the film layer.

[0015] Optionally, along a third direction, the thickness of the adhesive layer is greater than or equal to 2 micrometers and less than or equal to 100 micrometers.

[0016] Optionally, adjacent solar cells can be stacked. And / or, a preset interval is provided between adjacent solar cells.

[0017] Optionally, along the first direction, the length of the cut-hole area is less than or equal to 10 mm.

[0018] Optionally, along the first direction, the length of the cut-hole area is greater than or equal to 2 mm and less than or equal to 6 mm.

[0019] According to another aspect of the present invention, a method for preparing a battery string is provided, the method comprising: Multiple solar cells are provided; the multiple solar cells are connected sequentially along a first direction; A composite structure is formed; the composite structure includes: solder strips extending along a first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder strips away from the solar cell; the composite structure also has multiple cut-hole regions; along the first direction, the distance between the center of the cut-hole region and the intersection point of the center line of two adjacent edges of the adjacent solar cell along the second direction and the extension line of the solder strip is less than or equal to 5 mm; the cut-hole region penetrates the corresponding thin film layer and solder strip; the first direction and the second direction are perpendicular; The combined structure is placed on one side of multiple battery cells that are connected sequentially along the first direction.

[0020] Optionally, a combined structure can be formed, including: Provide solder strips; the solder strips extend along a first direction and are arranged in an array along a second direction; A thin film layer is formed on the side of the solder strip away from the solar cell; Multiple cut-hole regions are formed; along the first direction, the distance between the center of the cut-hole region and the intersection of the center line of the two adjacent edges of the adjacent cell along the second direction and the extension line of the solder strip is less than or equal to 5 mm; the cut-hole region penetrates the corresponding thin film layer and solder strip.

[0021] According to another aspect of the present invention, a battery assembly is provided, including a battery string according to any embodiment of the present invention.

[0022] According to another aspect of the present invention, a photovoltaic system is provided, including a battery module according to any embodiment of the present invention.

[0023] The technical solution of this invention provides a battery string, wherein the battery string includes multiple battery cells connected sequentially along a first direction, and a combined structure disposed on one side of the multiple battery cells; the combined structure includes solder ribbons extending along the first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder ribbons away from the battery cells; compared with the prior art, this invention avoids bending and disturbance of the solder ribbons and improves the situation of solder ribbon position displacement by first forming a combined structure with the arrayed solder ribbons and the thin film layer; in addition, the combined structure is also provided with multiple cut-hole areas, the center of the cut-hole area is correspondingly located at the intersection of the center line of two adjacent edges of adjacent battery cells along the second direction and the extension line of the solder ribbon, with a floating distance of no more than 5 mm, realizing the segmentation of the solder ribbons and stress release; the combined structure covers multiple pre-placed battery cells, and the battery string is formed by heat shrinking and pressing the solder ribbons together, reducing manufacturing costs, improving the reliability of the battery string, and enhancing the overall competitiveness of the product.

[0024] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a battery string structure provided according to an embodiment of the present invention; Figure 2 This is a partial structural schematic diagram of a battery string provided according to an embodiment of the present invention; Figure 3 This is a schematic cross-sectional view of a battery string according to an embodiment of the present invention; Figure 4 This is a schematic cross-sectional view of another battery string structure provided according to an embodiment of the present invention; Figure 5 This is a flowchart of a method for preparing a battery string according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of multiple battery cells provided according to an embodiment of the present invention; Figure 7 It is provided according to the embodiments of the present invention. Figure 5 The flowchart included in S120; Figures 8-10 It is provided according to the embodiments of the present invention. Figure 7 The structural diagrams corresponding to each step in the process. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Figure 1 This is a schematic diagram of a battery string structure provided according to an embodiment of the present invention. Figure 1 As shown, the battery string includes: multiple battery cells 10; the multiple battery cells 10 are connected sequentially along a first direction X; a combined structure 20 is located on one side of the multiple battery cells 10 connected sequentially along the first direction X; the combined structure 20 includes: a solder ribbon 201 extending along the first direction X and arranged in an array along the second direction Y, and a thin film layer 202 located on the side of the solder ribbon 201 away from the battery cells 10; the combined structure 20 also has multiple cut-hole regions 203; along the first direction X, the distance between the center of the cut-hole region 203 and the intersection point of the center line of two adjacent edges of the adjacent battery cell 10 along the second direction Y and the extension line of the solder ribbon 201 is less than or equal to 5 mm; the cut-hole region 203 penetrates the corresponding thin film layer 202 and solder ribbon 201; the first direction X and the second direction Y are perpendicular.

[0030] In an optional embodiment of the present invention, adjacent battery cells 10 are stacked; and / or, a preset interval is provided between adjacent battery cells 10.

[0031] In this embodiment of the invention, multiple battery cells 10 are typically connected in a stacked manner along the first direction X, meaning that the two adjacent edges of adjacent battery cells 10 partially overlap in the second direction Y to facilitate current conduction. A preset interval can also be provided between adjacent battery cells 10. The preset interval is the distance between two adjacent edges of adjacent battery cells set in advance. In this embodiment of the invention, adjacent battery cells 10 can be stacked or have a preset interval between them; no specific limitation is made here. The solder strip 201 is typically a tin-plated copper strip, possessing both conductivity and solderability. It serves both to collect the fine grid current and as the welding interface between the battery cell and external components. The thin film layer 202 is located on the side of the solder strip 201 away from the battery cell 10. The material of the thin film layer 202 includes insulating or semi-insulating materials that shrink when heated. In this embodiment of the invention, the material of the thin film layer 202 includes, but is not limited to, multilayer co-extruded polyolefins, thermoplastic polyurethane (TPU), thermoplastic polye (POE), cross-linked polyethylene (XLPE), polyvinylidene fluoride (PVDF), or polyvinylidene fluoride (PVF).

[0032] In this embodiment of the invention, by setting multiple cut-hole regions 203, the welding strip 201 is divided and stress is released. The cut-hole regions 203 are formed by methods including but not limited to laser or die stamping. The shape of the cut-hole regions 203 includes but is not limited to square, circular or rectangular, and this embodiment of the invention does not specifically limit the shape of the cut-hole regions 203.

[0033] Figure 2 This is a partial structural schematic diagram of a battery string according to an embodiment of the present invention. (Reference) Figure 1 and Figure 2 In this embodiment of the invention, along the first direction X, the center of the cut-hole area 203 can coincide with the intersection of the center line of the two adjacent edges of the adjacent battery cell along the second direction Y and the extension line of the solder ribbon 201. Alternatively, the center of the cut-hole area 203 can be set within a range of 5 mm above or below the intersection of the center line of the two adjacent edges of the adjacent battery cell along the second direction Y and the extension line of the solder ribbon 201. If the distance between the center of the cut-hole area 203 and the intersection of the center line of the two adjacent edges of the adjacent battery cell along the second direction Y and the extension line of the solder ribbon 201 is set too large, the solder ribbon 201 will press against the edge of the battery cell 10, causing the battery cell to break, and some current may not be collected. This embodiment of the invention can improve the contact reliability between the solder ribbon 201 and the battery cell 10.

[0034] In this embodiment of the invention, the solder ribbons 201 are first straightened and fixed side-by-side on an operating platform. A coating process is then used to fix the solder ribbons 201 by hot pressing, forming a combined structure 20 consisting of the solder ribbons 201 and a thin film layer 202. Holes are cut in specific areas of the combined structure 20 to form multiple cut-hole areas 203, achieving the segmentation of the solder ribbons 201 and stress release. The combined structure 20 is then used to cover the pre-placed battery cells 10, and the solder ribbons 201 are fixed and pressed together by heat shrinking to form a battery string.

[0035] It should be noted that, in this embodiment of the invention, the cross-sectional shape of the solder strip 201 includes, but is not limited to, circles, squares, and triangles, and this embodiment of the invention does not impose specific limitations on these shapes. The thickness of the solder strip 201 can be set to be greater than or equal to 10 micrometers and less than or equal to 500 micrometers. The width of the solder strip 201 along the second direction Y is not specifically limited in this embodiment of the invention. When the solder strip 201 is a round wire solder strip, that is, when the cross-sectional shape of the solder strip 201 is circular, the diameter of the circular cross-section can be set to be greater than or equal to 0.2 millimeters and less than or equal to 0.4 millimeters.

[0036] The technical solution of this invention provides a battery string, wherein the battery string includes multiple battery cells connected sequentially along a first direction, and a combined structure disposed on one side of the multiple battery cells; the combined structure includes solder ribbons extending along the first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder ribbons away from the battery cells; compared with the prior art, this invention avoids bending and disturbance of the solder ribbons and improves the situation of solder ribbon position displacement by first forming a combined structure with the arrayed solder ribbons and the thin film layer; in addition, the combined structure is also provided with multiple cut-hole areas, the center of the cut-hole area is correspondingly located at the intersection of the center line of two adjacent edges of adjacent battery cells along the second direction and the extension line of the solder ribbon, with a floating distance of no more than 5 mm, realizing the segmentation of the solder ribbons and stress release; the combined structure covers multiple pre-placed battery cells, and the battery string is formed by heat shrinking and pressing the solder ribbons together, reducing manufacturing costs, improving the reliability of the battery string, and enhancing the overall competitiveness of the product.

[0037] In an optional embodiment of the present invention, reference is made to... Figure 1 Along the second direction Y, multiple cutting hole areas 203 are located on the same first horizontal line 31, or on a second horizontal line 32 parallel to the first horizontal line 31; along the first direction X, the first horizontal line 31 and the second horizontal line 32 are alternately arranged.

[0038] In this embodiment of the invention, along the second direction Y, the cut-out areas 203 corresponding to the positive electrode grid lines of the battery cell 10 are located on the same horizontal line; the cut-out areas 203 corresponding to the negative electrode grid lines of the battery cell 10 are also located on the same horizontal line. When the cut-out areas 203 corresponding to the positive electrode grid lines of the battery cell 10 are located on the same first horizontal line 31, the cut-out areas 203 corresponding to the negative electrode grid lines of the battery cell 10 are located on a second horizontal line 32 parallel to the first horizontal line 31; similarly, when the cut-out areas 203 corresponding to the negative electrode grid lines of the battery cell 10 are located on the same first horizontal line 31, the cut-out areas 203 corresponding to the positive electrode grid lines of the battery cell 10 are located on a second horizontal line 32 parallel to the first horizontal line 31. The specific settings are determined according to actual needs, and this embodiment of the invention does not impose specific limitations on this.

[0039] By positioning multiple cut-hole areas 203 in this way, the current density of the solder ribbon 201 can be balanced, resulting in a more uniform current distribution on the solder ribbon 201. This avoids efficiency degradation of the battery cell 10 caused by localized overheating and improves the reliability of the battery string. At the same time, it can prevent stress from accumulating in the same lateral position, avoiding microcracks or breakage of the battery cell 10 during lamination or subsequent use, thus enhancing the overall competitiveness of the product.

[0040] In an optional embodiment of the present invention, reference is made to... Figure 1 Along the second direction Y, the spacing between the cut-hole areas 203 located on the same first horizontal line 31 or the same second horizontal line 32 is an even multiple of the spacing between adjacent weld strips 201.

[0041] In this embodiment of the invention, with Figure 1 For illustration, the spacing between the cut-hole areas 203 located on the same second horizontal line 32 includes a first distance L and a second distance M, and the spacing P between adjacent solder strips 201. The first distance L is equal to twice the spacing P between adjacent solder strips 201; the second distance M is equal to four times the spacing P between adjacent solder strips 201. That is, L=2P; M=4P. This setting can make the current path more uniform, reduce series resistance, avoid local current concentration in the solder strips, reduce the alignment difficulty of automated processes, and improve the yield of battery strings; at the same time, it can also enhance structural symmetry and reduce stress concentration.

[0042] It should be noted that the spacing P between adjacent weld strips 201 represents the distance between the center points of each adjacent weld strip 201; the spacing between the cut hole areas 203 represents the distance between the center points of each cut hole area 203.

[0043] In an optional embodiment of the present invention, reference is made to... Figure 1Along the second direction Y, the spacing between the cut-hole area 203 on the first horizontal line 31 and the cut-hole area 203 on the second horizontal line 32 is an odd multiple of the spacing between adjacent weld strips 201.

[0044] In this embodiment of the invention, with Figure 1 For illustration, the spacing between the cut-hole area 203 on the first horizontal line 31 and the cut-hole area 203 on the second horizontal line 32 includes a third distance Q and a fourth distance N, and the spacing P between adjacent solder strips 201. The third distance Q is equal to one times the spacing P between adjacent solder strips 201; the fourth distance N is equal to three times the spacing P between adjacent solder strips 201. That is, Q=P; N=3P. This setting can make the current path more uniform, reduce series resistance, avoid local current concentration in the solder strips, reduce the alignment difficulty of automated processes, and improve the yield of battery strings; at the same time, it can also enhance structural symmetry and reduce stress concentration.

[0045] In an optional embodiment of the present invention, reference is made to... Figure 1 The cut-hole area 203 located on the first horizontal line 31 and the cut-hole area 203 located on the second horizontal line 32 are both disposed on the same thin film layer 202.

[0046] In this embodiment of the invention, the thin film layer 202 located on one side of a plurality of battery cells 10 sequentially connected along the first direction X is the same thin film layer. Therefore, the cut-hole area 203 located on the first horizontal line 31 and the cut-hole area 203 located on the second horizontal line 32 are both disposed on the same thin film layer 202. This arrangement can improve production efficiency and increase product yield.

[0047] In an optional embodiment of the present invention, reference is made to... Figure 1 and Figure 2 Along the second direction Y, the width W of the cut hole area 203 is greater than the width W1 of the solder strip 201 and less than the spacing P between adjacent solder strips 201.

[0048] In this embodiment of the invention, the width W of the cut-hole region 203 is wider than the width W1 of the solder strip 201, but narrower than the spacing P between adjacent solder strips 201. This arrangement ensures effective contact between the solder strip 201 and the battery cell 10, and guarantees that the shrinkage force of the thin film layer 202 effectively presses the solder strip 201. If the width W of the cut-hole region 203 is set too large, the cut-hole region 203 will extend into the adjacent solder strip region, which may cause a short circuit fault between adjacent solder strips. This arrangement can also avoid unnecessary light shading and improve the conversion efficiency of the battery string.

[0049] Figure 3 This is a schematic cross-sectional view of a battery string according to an embodiment of the present invention. In an optional embodiment of the present invention, reference is made to... Figure 1 and Figure 3 Along the third direction Z, the thickness of the thin film layer 202 is greater than or equal to 50 micrometers and less than or equal to 300 micrometers; the third direction Z is perpendicular to both the first direction X and the second direction Y.

[0050] In this embodiment of the invention, the thickness of the thin film layer 202 is set to be greater than or equal to 50 micrometers to ensure that the thin film layer 202 has sufficient shrinkage force and insulation performance; at the same time, the thickness of the thin film layer 202 is set to be less than or equal to 300 micrometers to avoid excessive stress caused by the thin film layer 202 being too thick, and to control production costs. When the solder ribbon 201 is coated, the thin film layer 202 cannot be pierced, but can only be deformed and arched by the solder ribbon 201, and the solder ribbon is tightly adhered to the battery cell 10 by heat shrinking and pressing.

[0051] Figure 4 This is a schematic cross-sectional view of another battery string structure provided according to an embodiment of the present invention; in an optional embodiment of the present invention, refer to Figure 1 , Figure 3 and Figure 4 The battery string also includes: an adhesive layer 30; the adhesive layer 30 is located between the solder ribbon 201 and the thin film layer 202; and / or, the adhesive layer 30 is located between the battery cell 10 and the thin film layer 202.

[0052] In this embodiment of the invention, the adhesive layer 30 can enhance the integrity of the combined structure 20 and improve its mechanical strength. At the same time, the adhesive layer 30 can also improve the contact stability between the welding ribbon 201 and the battery cell 10, improve the insulation performance, and reduce the occurrence of short circuit faults.

[0053] In an optional embodiment of the present invention, reference is made to... Figure 1 , Figure 3 and Figure 4 Along the third direction Z, the thickness of the adhesive layer 30 is less than the thickness of the thin film layer 202.

[0054] In this embodiment of the invention, the thickness of the adhesive layer 30 is set to be less than the thickness of the thin film layer 202, because when the solder ribbon 201 is coated, the adhesive layer 30 can be penetrated by the solder ribbon 201, while the thin film layer 202 cannot be penetrated, but can only be deformed and arched by the solder ribbon 201.

[0055] In an optional embodiment of the present invention, reference is made to... Figure 1 , Figure 3 and Figure 4 Along the third direction Z, the thickness of the adhesive layer 30 is greater than or equal to 2 micrometers and less than or equal to 100 micrometers.

[0056] In this embodiment of the invention, the thickness of the adhesive layer 30 is greater than or equal to 2 micrometers and less than or equal to 100 micrometers. This ensures sufficient adhesive strength, good insulation performance, and effective stress buffering, while also preventing stress concentration or interlayer delamination caused by excessive thickness of the adhesive layer 30. The material of the adhesive layer 30 can be a room-temperature adhesive material (such as acrylate or silicone rubber) or a hot-tack material (such as ethylene-vinyl acetate copolymer EVA or butyl rubber).

[0057] In an optional embodiment of the present invention, reference is made to... Figure 1 and Figure 2 Along the first direction X, the length of the cut hole area 203 is less than or equal to 10 mm.

[0058] In this embodiment of the invention, the length range of the cut-out area 203 along the first direction X is set to improve the reliability of the battery string structure. If the size of the cut-out area 203 along the first direction X is too large, some current will not be collected.

[0059] In an optional embodiment of the present invention, reference is made to... Figure 1 and Figure 2 Along the first direction X, the length of the cut hole area 203 is greater than or equal to 2 mm and less than or equal to 6 mm.

[0060] In this embodiment of the invention, if the size of the cut-out area 203 along the first direction X is too small, a short circuit is likely to occur; if the size of the cut-out area 203 along the first direction X is too large, some current will not be collected. This arrangement can further improve the reliability of the battery string and increase the product yield.

[0061] Figure 5 This is a flowchart illustrating a method for preparing a battery string according to an embodiment of the present invention. This method can be performed by a battery string preparation apparatus. Figure 5 As shown, the method for fabricating this battery string includes: S110, Provides multiple battery cells; The multiple battery cells are connected sequentially along a first direction.

[0062] Figure 6 This is a schematic diagram of the structure of multiple battery cells according to an embodiment of the present invention. (Reference) Figure 6 The system provides multiple solar cells 10; the multiple solar cells 10 are connected sequentially along a first direction X. The multiple solar cells 10 are typically connected in a stacked manner, that is, the edges of adjacent solar cells 10 partially overlap to facilitate current conduction.

[0063] S120, forming a combined structure; the combined structure includes: solder strips extending along a first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder strips away from the battery cell; the combined structure also has multiple cut-hole regions; along the first direction, the distance between the center of the cut-hole region and the intersection point of the center line of two adjacent edges of the adjacent battery cell along the second direction and the extension line of the solder strip is less than or equal to 5 mm; the cut-hole region penetrates the corresponding thin film layer and solder strip; the first direction and the second direction are perpendicular.

[0064] refer to Figure 1 The combined structure 20 is formed, comprising: a solder ribbon 201 extending along a first direction X and arranged in an array along a second direction Y, and a thin film layer 202 located on the side of the solder ribbon 201 away from the solar cell 10; the combined structure 20 is also provided with a plurality of cut-hole regions 203; along the first direction X, the distance between the center of the cut-hole region 203 and the intersection point of the center line of two adjacent edges of the adjacent solar cell along the second direction Y and the extension line of the solder ribbon 201 is less than or equal to 5 mm; the cut-hole region 203 penetrates the corresponding thin film layer 202 and solder ribbon 201; the first direction X and the second direction Y are perpendicular.

[0065] In this embodiment of the invention, the welding strip 201 can be straightened and fixed side by side on the operating platform. A coating process is used to fix the welding strip 201 by hot pressing and form a combined structure 20 consisting of the welding strip 201 and a thin film layer 202. Holes are cut in specific areas of the combined structure 20 to form multiple cut-hole areas 203, thereby achieving the segmentation of the welding strip 201 and stress release.

[0066] S130, The combined structure is disposed on one side of a plurality of battery cells that are connected sequentially along the first direction.

[0067] In an embodiment of the present invention, reference is made to Figure 1 The pre-placed battery cells 10 are covered by the combined structure 20, and the heat-shrinkable bonding tape 201 is used to form a battery string.

[0068] The technical solution of this invention provides a battery string, comprising multiple battery cells sequentially connected along a first direction, and a combined structure disposed on one side of the multiple battery cells. The combined structure includes solder ribbons extending along the first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder ribbons away from the battery cells. Compared with the prior art, this invention avoids bending and disturbance of the solder ribbons and improves the situation of solder ribbon position displacement by first forming a combined structure with the arrayed solder ribbons and the thin film layer. In addition, the combined structure is provided with multiple cut-hole areas, the center of which is located at the intersection of the center line of two adjacent edges of adjacent battery cells along the second direction and the extension line of the solder ribbon, with a floating distance of no more than 5 mm, realizing the segmentation of the solder ribbons and stress release. The combined structure covers multiple pre-placed battery cells, and the battery string is formed by heat shrinking and pressing the solder ribbons together, reducing manufacturing costs, improving the reliability of the formed battery string, and enhancing the overall competitiveness of the product.

[0069] The battery string preparation method of this invention is used to prepare battery strings of any embodiment of this invention and has corresponding beneficial effects.

[0070] Figure 7 It is provided according to the embodiments of the present invention. Figure 5 The flowchart included in S120. In an optional embodiment of the invention, refer to... Figure 7 S120, forming a combined structure, including: S1201, Provide solder strips; the solder strips extend along a first direction and are arranged in an array along a second direction.

[0071] refer to Figure 8 The invention provides a solder strip 201; the solder strip 201 extends along a first direction X and is arranged in an array along a second direction Y. In this embodiment of the invention, the solder strip 201 can be straightened first and fixed side by side on the operating platform.

[0072] S1202, A thin film layer is formed on the side of the solder ribbon away from the solar cell.

[0073] refer to Figure 9 The coating process is adopted, and the solder strip 201 is fixed by hot pressing to form a combined structure 20 consisting of solder strip 201 and thin film layer 202.

[0074] S1203, forming multiple cut-hole areas; along the first direction, the distance between the center of the cut-hole area and the intersection of the center line of the two adjacent edges of the adjacent cell along the second direction and the extension line of the solder strip is less than or equal to 5 mm; the cut-hole area penetrates the corresponding thin film layer and solder strip.

[0075] refer to Figure 10Holes are cut in specific areas of the composite structure 20 to form multiple cut-hole regions 203, thereby achieving the segmentation of the weld strip 201 and stress relief. The methods for forming the cut-hole regions 203 include, but are not limited to, laser cutting or die stamping. The shapes of the cut-hole regions 203 include, but are not limited to, square, circular, or rectangular.

[0076] This invention provides a battery assembly, wherein the battery assembly includes the battery string provided in any of the above embodiments of this invention.

[0077] A battery module may include multiple solar cells, which can be connected in series to form a battery string. These battery strings can be connected in series, parallel, or a combination of series and parallel to achieve current output. For example, the connection between individual cells can be achieved by welding ribbons, or the connection between battery strings can be achieved by busbars. The battery module may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film can be filled between the light-facing side of the solar cells and the photovoltaic glass, the back-facing side and the backsheet, and adjacent cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film can be EVA film or POE film; the specific choice depends on the actual situation and is not limited here.

[0078] Photovoltaic glass can be applied to the encapsulating film on the light-facing side of a solar cell. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the solar cell while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the solar cell together, providing sealing, insulation, and waterproofing / moisture protection for the solar cell.

[0079] The backsheet can be attached to the encapsulating film on the back side of the solar cell. The backsheet protects and supports the solar cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite encapsulating film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell, encapsulating film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0080] The battery assembly provided in the embodiments of the present invention has the beneficial effects of the battery string provided in any of the above embodiments of the present invention.

[0081] This invention provides a photovoltaic system, wherein the photovoltaic system includes the battery module provided in the above embodiments of this invention, and has the beneficial effects of the battery module provided in the above embodiments of this invention.

[0082] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted, rooftop, and floating power plants, as well as in equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it's understandable that the application scenarios of photovoltaic systems are not limited to these; that is, photovoltaic systems can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation network as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. A photovoltaic array can be a combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which collect the current generated by the photovoltaic arrays. The collected current flows through an inverter and is converted into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0083] Since the battery module provided in the embodiments of the present invention has the beneficial effects of any battery string provided in any of the above embodiments of the present invention, the photovoltaic system provided in the embodiments of the present invention has the beneficial effects of any battery string provided in any of the above embodiments of the present invention.

[0084] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0085] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A battery string, characterized in that, include: Multiple battery cells; The plurality of battery cells are connected sequentially along a first direction; A composite structure is located on one side of a plurality of battery cells connected sequentially along the first direction; the composite structure includes: solder ribbons extending along the first direction and arranged in an array along the second direction, and a thin film layer located on the side of the solder ribbons away from the battery cells; The combined structure is further provided with multiple cut-hole areas; along the first direction, the distance between the center of the cut-hole area and the intersection point of the center line of the two adjacent edges of the adjacent battery cell along the second direction and the extension line of the solder strip is less than or equal to 5 mm; the cut-hole area penetrates the corresponding thin film layer and the solder strip; the first direction and the second direction are perpendicular.

2. The battery string according to claim 1, characterized in that, Along the second direction, the plurality of said cutting hole areas are located on the same first horizontal line, or on a second horizontal line parallel to the first horizontal line; Along the first direction, the first horizontal line and the second horizontal line are alternately set.

3. The battery string according to claim 2, characterized in that, Along the second direction, the spacing between the cut-hole areas located on the same first horizontal line or the same second horizontal line is an even multiple of the spacing between adjacent weld strips.

4. The battery string according to claim 2, characterized in that, Along the second direction, the distance between the cut-hole area located on the first horizontal line and the cut-hole area located on the second horizontal line is an odd multiple of the distance between adjacent solder strips.

5. The battery string according to claim 2, characterized in that, The cut-hole area located on the first horizontal line and the cut-hole area located on the second horizontal line are both disposed on the same thin film layer.

6. The battery string according to claim 1, characterized in that, Along the second direction, the width of the cut-hole area is greater than the width of the solder strip and less than the spacing between adjacent solder strips.

7. The battery string according to claim 1, characterized in that, Along a third direction, the thickness of the thin film layer is greater than or equal to 50 micrometers and less than or equal to 300 micrometers; the third direction is perpendicular to both the first direction and the second direction.

8. The battery string according to claim 1, characterized in that, The battery string further includes: an adhesive layer; the adhesive layer is located between the solder strip and the thin film layer; And / or, The adhesive layer is located between the battery cell and the thin film layer.

9. The battery string according to claim 8, characterized in that, Along a third direction, the thickness of the adhesive layer is less than the thickness of the film layer.

10. The battery string according to claim 9, characterized in that, Along the third direction, the thickness of the adhesive layer is greater than or equal to 2 micrometers and less than or equal to 100 micrometers.

11. The battery string according to claim 1, characterized in that, The adjacent battery cells are stacked together; And / or, a preset interval is provided between adjacent battery cells.

12. The battery string according to claim 1, characterized in that, Along the first direction, the length of the cut-hole area is less than or equal to 10 mm.

13. The battery string according to claim 1, characterized in that, Along the first direction, the length of the cut-hole area is greater than or equal to 2 mm and less than or equal to 6 mm.

14. A method for preparing a battery string, characterized in that, include: Multiple battery cells are available; The plurality of battery cells are connected sequentially along a first direction; A combined structure is formed; the combined structure includes: solder ribbons extending along a first direction and arranged in an array along a second direction, and a thin film layer located on the side of the solder ribbons away from the battery cell; the combined structure also has a plurality of cut-hole regions; along the first direction, the distance between the center of the cut-hole region and the intersection point of the center line of two adjacent edges of the adjacent battery cell along the second direction and the extension line of the solder ribbon is less than or equal to 5 mm; the cut-hole region penetrates the corresponding thin film layer and the solder ribbon; the first direction and the second direction are perpendicular; The combined structure is disposed on one side of a plurality of battery cells that are connected sequentially along the first direction.

15. The method for preparing the battery string according to claim 14, characterized in that, Forming a composite structure, including: Provide solder strips; the solder strips extend along the first direction and are arranged in an array along the second direction; A thin film layer is formed on the side of the solder strip away from the battery cell; Multiple cut-hole areas are formed; along the first direction, the distance between the center of the cut-hole area and the intersection of the center line of the two adjacent edges of the adjacent battery cell along the second direction and the extension line of the solder strip is less than or equal to 5 mm; the cut-hole area penetrates the corresponding thin film layer and the solder strip.

16. A battery assembly, characterized in that, Includes the battery string as described in any one of claims 1-13.

17. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 16.

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