Battery Assembly and Photovoltaic System

Abstract

The present invention is applicable to the field of photovoltaic technology, and provides a battery component and a photovoltaic system. Each battery cell includes a chamfered edge with a chamfer and a cut edge formed by cutting without a chamfer. The chamfered edge and the cut edge in the battery cell are opposite to each other. A plurality of the battery cells are sequentially and partially overlapped along a first direction to form a plurality of overlapping regions. In the technical solution of the present invention, by recording and experimenting on the sizes, material properties, lamination widths of different battery cells and the comprehensive performance of the corresponding battery components, a relationship model for the upper limit of the lamination width of the battery component is established, that is, the upper limit of the width d of the overlapping region satisfies the following relational expression: d ≤ (L1 - L2) / 2 * tanθ + L1 / (L2 * a * σ). The comprehensive performance of the battery component is optimal. When designing the lamination widths of different battery cells, substituting the size and material properties of the target battery cell to be designed into the relationship model can design the upper limit of the lamination width of the battery cell that meets the optimal comprehensive performance of the target battery component.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaics, and particularly relates to a battery module and a photovoltaic system. Background Art

[0002] A solar cell is a device that utilizes solar energy to directly convert light energy into electrical energy through the photovoltaic effect or the photochemical effect. Solar cells include segmented solar cells. Currently, when manufacturing segmented solar cells, it is usually to cut a solar cell that has already formed multiple film layers to cut the entire solar cell into at least two segmented solar cells, such as two half-cells. Then, the segmented solar cells are used to manufacture photovoltaic modules. Since the voltage output by a single cell is relatively low, a certain number of cells are usually connected in series to form a cell string. Among them, the laminated module is widely used because it can eliminate the gap between the cells and increase the light-receiving area on the front side of the photovoltaic module, thereby improving the photoelectric conversion efficiency of the photovoltaic module. The laminated module is to locally overlap multiple cells in sequence. When designing the overlapping distance between the cells, the size of the overlapping distance needs to be reasonably designed. When the overlapping distance is too small, the risk of hidden cracks is relatively large, affecting the yield of the battery module. When the overlapping distance is too large, it will reduce the light-receiving area of the cell, affecting the photoelectric conversion efficiency of the battery module. Considering the comprehensive performance in the production of the battery module, it is necessary to select a reasonable overlapping distance, which can ensure the efficiency of the battery module on the basis of having a relatively small impact on the production yield of the battery module. There is a lack of a design method for the overlapping width between the cells in the prior art, resulting in the problem of relatively low efficiency of the current battery module. Summary of the Invention

[0003] The present invention provides a battery module, aiming to solve the problem that there is a lack of a design method for the overlapping width between the cells in the prior art, resulting in relatively low efficiency of the current battery module.

[0004] The present invention is implemented as follows. A battery module includes a plurality of cells. Each cell includes a chamfered edge with a chamfer and a cut edge formed by cutting without a chamfer. The chamfered edge and the cut edge of the cell are opposite. The plurality of cells are sequentially and partially overlapped along a first direction to form a plurality of overlapping regions. The chamfered edge of one of the adjacent two cells and the cut edge of the other cell are overlapped. The width d of each overlapping region in the first direction satisfies the following relationship: d ≤ (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), where L1 is the length of the cut edge of the cell, in mm; L2 is the length of the chamfered edge of the cell, in mm; θ is the chamfer angle of the cell, in rad; a is a correction coefficient, and a is 0.05 mm -1 *Mpa -1; σ is the structural strength of the cell, with the unit of Mpa; among them, the structural strength σ of the cell satisfies the following relational expression: σ = b / (L1*h 2 ), where b is a constant, and the value of b is 620 mm -1 *Mpa -1 ; L1 is the length of the cutting edge of the cell, with the unit of mm; h is the thickness of the cell, with the unit of mm.

[0005] Optionally, the length of the chamfered edge is L1, the length of the cutting edge is L2, and the difference between the L1 and the L2 is greater than or equal to 1 mm and less than or equal to 10 mm.

[0006] Optionally, the range of the length of the L1 is 150 mm to 250 mm.

[0007] Optionally, the range of the length of the L2 is 140 mm to 240 mm.

[0008] Optionally, the range of the angle θ of the chamfer of the cell is greater than 0 and less than π / 2.

[0009] Optionally, the range of the structural strength σ of the cell is 20 to 300 Mpa.

[0010] Optionally, the range of the thickness of the cell is 0.05 to 0.5 mm.

[0011] Optionally, the chamfered edges of the cells are stacked on the cutting edges of adjacent cells.

[0012] Optionally, the widths of each of the multiple overlapping regions in the first direction are equal.

[0013] In the technical solution of the present invention, by recording and experimenting on the sizes, material properties, lamination widths of different cells and the comprehensive performance of the corresponding battery modules, a relational model for the upper limit of the lamination width of the battery module is established, that is, the width d of the overlapping region satisfies the following relational expression: d ≤ (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), and the comprehensive performance of the battery module is the best. After exceeding this upper limit, the efficiency of the battery module drops sharply, and the comprehensive performance of the module cannot meet the factory standards. Through the above design of the relational expression of the lamination width, when designing the lamination width of different cells, substituting the size and material properties of the target cell to be designed into the relational model can design the upper limit of the lamination width of the cell that meets the best comprehensive performance of the target battery module. At the same time, by designing the overlapping width between cells through the above relational expression model, it has the characteristics of fast design and high efficiency, which helps the production decision-making of the product.

[0014] A photovoltaic system includes the above-mentioned battery modules. The technical effects of the present invention are the same as those of the above-mentioned battery modules and will not be elaborated herein. Description of the Drawings

[0015] Figure 1 is a schematic structural view of the battery chip provided by the present invention;

[0016] Figure 2 is a schematic structural view of the first battery module provided by the present invention;

[0017] Figure 3 is a schematic structural view of the second battery module provided by the present invention;

[0018] Figure 4 is a schematic structural view of the third battery module provided by the present invention.

[0019] Description of the Reference Numerals:

[0020] 100, battery chip; 101, chamfered edge; 102, cutting edge; 200, overlapping area; 300, bevel edge; 400, side edge. Detailed Embodiments

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. Examples of the embodiments are shown in the drawings, wherein 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 drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0023] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0024] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include direct contact between the first and second features, or may include indirect contact between the first and second features through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0026] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0027] As Figure 1As shown, in an embodiment of the present invention, a battery assembly includes a plurality of battery wafers 100. Each battery wafer 100 includes a chamfered edge 101 with a chamfer and a cut edge 102 formed by cutting without a chamfer. It should be noted that in the embodiments of the present application, the battery wafers 100 are usually formed by slicing a single-crystalline silicon rod. The single-crystalline silicon rod is generally cylindrical. In order to maximize the light-receiving area and save silicon rod materials, the battery wafers 100 formed by slicing the single-crystalline silicon rod usually have right angles. In order to make the corners of the battery wafers 100 smoother and reduce the corner stress, etc., it is usually necessary to chamfer the right angles so that the battery wafers 100 have four chamfers. In addition, in order to make the battery wafers 100 have different specifications and can be applied to different environments, the battery wafers 100 can be further cut into multiple small-sized battery wafers 100. Exemplarily, the battery wafers 100 in the embodiments of the present application can be half-cell wafers obtained by scribing a whole-cell wafer. The four corners of the whole-cell wafer are all chamfered. One side of the half-cell wafer formed by slicing is the chamfered edge 101, and the other side is a right-angle edge. The chamfered edge 101 is a non-cut edge 102, and the right-angle edge is a cut edge 102. The chamfered edge 101 of the half-cell wafer is the chamfered edge 101 of the whole-cell wafer 100, and the right-angle edge of the half-cell wafer 100 is the cut edge 102 formed by slicing the whole-cell wafer 100.

[0028] In some embodiments, the two sides of any battery wafer 100 along the first direction are respectively the chamfered edge 101 and the cut edge 102. Any battery wafer also has two side edges 400 in the second direction. The chamfered edge 101 and the cut edge 102 are opposite to each other, and the two side edges 400 are opposite to each other. Further, the chamfered edge 101 of the battery wafer 100 has a chamfered structure at both corners in the second direction. The chamfered structure has an inclined side 300, and the inclined side 300 connects the adjacent side edge 400 and the chamfered edge 101. One side edge of the battery wafer 100 has a chamfered structure in the second direction, and this side edge of the battery wafer 100 is the chamfered edge 101; the other side edge of the battery wafer 100 has a right-angle structure in the second direction, and this side edge of the battery wafer 100 is the cut edge 102.

[0029] In the embodiments of the present application, the second direction intersects the first direction. Specifically, the second direction can be perpendicular to the first direction. Exemplarily, the first direction can be the width direction of the battery wafer 100, and the second direction can be the length direction of the battery wafer 100.

[0030] As Figure 2As shown, in some embodiments, the chamfered edge 101 and the cut edge 102 in the cell 100 are opposite to each other. A plurality of cells 100 are arranged in a partially overlapping manner in sequence along the first direction to form a plurality of overlapping regions 200. The chamfered edge 101 of one of the adjacent two cells 100 overlaps with the cut edge 102 of the other. Specifically, the battery module includes a plurality of cells. The plurality of cells can be connected in series to form a battery string, and the plurality of battery strings can be connected in series or in parallel to form a battery module.

[0031] In the back-contact battery module, the contact areas between the overlaps are not electrically connected. That is, no conductive adhesive or other bonding adhesive needs to be provided between the overlapping regions 200. The cells 100 only need to overlap with each other. Among them, adjacent cells 100 in the battery string are connected in series by a solder ribbon. The overlapping region 200 can be fixedly connected by the series-connected solder ribbon. Among them, the series-connected solder ribbon is located on the back side of the cell 100. In this way, there is no gap between the cells 100, so that the solder ribbon can be better hidden. And through the overlapping arrangement of the cells 100, the size of the battery module can be reduced, and thus the occupied space of the battery string can be smaller. Or rather, when the size of the battery module is fixed, more cells 100 can be placed, improving the power of the battery string and reducing the cost per watt.

[0032] In some embodiments, from the perspective of the light-receiving surface of the battery module, the laminating method of the cells 100 can be specifically selected as follows: the chamfered edge 101 of the second cell overlaps on the cut edge 102 of the first cell, the chamfered edge 101 of the third cell overlaps on the cut edge 102 of the second cell, and so on in layers until the last Nth cell, where N is a positive integer; or the cut edge 102 of the second cell overlaps on the chamfered edge 101 of the first cell, the cut edge 102 of the third cell overlaps on the chamfered edge 101 of the second cell, and so on in layers until the last Nth cell, where N is a positive integer. Or, there can also be both of the above two overlapping methods in the battery module. It should be noted that since each cell 100 has a cut edge 102 and a chamfered edge 101 arranged oppositely, by overlapping the chamfered edges 101 and the cut edges 102 of the plurality of cells 100, the overlapping method of every two adjacent cells 100 is the same, which helps the layout of the battery module and simplifies the layout steps.

[0033] It should be noted that the setting of the lamination width of the cell 100 will affect the efficiency of the battery module. Specifically, the cells 100 are overlapped. Compared with the conventional method of setting intervals between cells, in a module layout of the same size, the proportion of the light-receiving area available for the lamination structure of the module increases. However, on the other hand, the overlap between the cells 100 will cause partial occlusion of the cells. The efficiency improvement brought about by the increased proportion of the light-receiving area of the module and the efficiency loss of the module caused by the partial occlusion of the cells need to be balanced through reasonable design of the lamination width. In addition, the cutting edge 102 of the cell 100 overlaps with the chamfered edge 101 of the adjacent cell 100. Due to the uneven current distribution at the edge of the cell 100, when the overlap width between the cells 100 reaches a certain limit point, the efficiency of the module will drop suddenly. This is also a factor that needs to be considered when designing the lamination width.

[0034] Based on the above overlapping method of two adjacent cells 100 and the comprehensive consideration of the above various influencing factors, through numerical simulation and experimental testing, the functional relationship between the material physical property parameters, structural parameters of the cell 100 and the lamination width of the cell is fitted, and the inventor establishes a design calculation model for the upper limit of the lamination width. The width d of each overlapping region 200 in the first direction satisfies the following relationship: d ≤ (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), where L1 is the length of the cutting edge of the cell, in mm, L2 is the length of the chamfered edge of the cell, in mm, θ is the chamfer angle of the cell, in rad, a is a correction coefficient, in 0.05 mm -1 *Mpa -1 , and σ is the structural strength of the cell, in Mpa. Among them, L1, L2, and θ of the cell in the formula determine the shape and structure of the cell 100. The structural strength of the cell 100 is related to the material properties of the cell 100. During the encapsulation process of the battery module, since the thickness of the overlapping region of the cells is twice the thickness of the non-overlapping region, mechanical stress concentration may be formed. This stress will cause the risk of latent cracks (microscopic cracks) in the cell 100, which may further lead to the failure of the module. Therefore, when designing the lamination width, the material properties of the cell 100 need to be considered to further correct the upper limit of the lamination width, improve the risk of latent cracks in the cells during the encapsulation process, and thus achieve the long-term stability of the battery module.

[0035] Furthermore, in some embodiments, according to the thickness h of different cells 100, the length L1 of the cutting edge 102 and the corresponding structural strength σ, through numerical simulation and experimental testing, the functional relationship between the thickness of the cell 100, the length L1 of the cutting edge 102 and the structural strength σ is further fitted. The structural strength σ of the cell 100 satisfies the following relationship: σ = b / (L1 * h 2), where b is a constant with a value of 620 mm -1 *Mpa -1 ; L1 is the length of the cut edge of the cell, in mm; h is the thickness of the cell, in mm. In the embodiments of the present application, by performing function fitting on the experimental data of the structural strength test of the cell 100, the associated physical quantities and the constant value b of the structural strength of the cell 100 are obtained. That is to say, by substituting the physically measurable quantities such as the length and thickness of the cell 100 into the above formula, the structural strength of the cell 100 can be obtained, thus avoiding the drawback that the material properties of the cell 100 cannot be directly obtained, and further expanding the application range of the design formula.

[0036] Furthermore, the fitting of the constant b value in the following relational formula for the structural strength σ is described: In the embodiments of the present application, based on the test of the structural strength of several cells, the calculation constant of the structural strength of the back-contact cell based on a single-crystalline silicon substrate is fitted according to the four-point structural strength calculation formula.

[0037] The four-point bending test used in the embodiments of the present application measures the maximum resistance of a material under a bending load by applying four loading points (two support points and two loading points) to the test piece. It is widely used to test the mechanical strength of photovoltaic modules (such as silicon wafers or glass substrates) because these materials are usually brittle and vulnerable to local stress concentration. The test device includes two lower support points and two upper loading points, forming an inner and outer span. The test piece is stressed under four-point loading, and the maximum bending stress occurs in the area between the two upper loading points. Compared with the conventional three-point structural test, the stress distribution in the four-point test is more uniform, avoiding local stress concentration caused by single-point loading, so it is more suitable for evaluating the overall structural performance of materials. The calculation formula for the structural strength is: σ = (3F x L) / (2b x h 2 ), where the structural strength σ (unit: MPa or N / mm 2 ), F: the maximum load (unit: N), that is, the force when the test piece breaks, L: the outer span (unit: mm), that is, the distance between the two lower support points, the width of the test piece (unit: mm), h: the thickness of the test piece (unit: mm). The data obtained by the four-point structural strength test and the corresponding structural strength calculation constants are as follows:

[0038]

[0039] In the present application, based on multiple groups of test data obtained from the four-point structural strength test, the calculation constant of the structural strength of the single-crystalline silicon cell is fitted, and then the calculation formula for the structural strength is refitted to obtain the formula σ = b / (L1 * h 2) According to the structural dimensions of the cell, the structural strength of the cell can be obtained quickly and simply, and the structural strength calculation constant is applicable to various common specifications of cells, with the error within the range allowed by the production process.

[0040] Especially in some special usage scenarios, for example, after the cells 100 are encapsulated to form a battery module. Since the space between the cells 100 is filled with solidified glue film and the glue film is bonded to the backplane glass, multiple cells 100 form an integral whole. At this time, it is impossible to separately peel out the cells 100 completely. Based on the above calculation formula for the structural strength of the cell, the structural strength of the cell 100 can be obtained by calculating multiple measurable physical quantities of the cell 100, providing a theoretical basis for experimental verification.

[0041] In other aspects, during the encapsulation process of the battery module, due to the need for a lamination process, the overlapping cells 100 have a relatively high risk of hidden cracks. Increasing the lamination distance between the cells can improve the risk of hidden cracks during the encapsulation process. However, an excessive lamination distance of the cells 100 will cause a relatively serious power loss in the module. The module efficiency has a large proportion in the comprehensive performance evaluation of the module performance, and the loss of module efficiency is unacceptable. Through repeated research and verification by the inventor, it is shown that when the lamination distance reaches (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), and the lamination distance continues to increase, the risk of hidden cracks in the cells during the module encapsulation process no longer decreases, but the power loss still gradually increases. Therefore, we believe that (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ) is the upper limit value of the lamination distance. Beyond this upper limit value, there is no benefit for either the risk of hidden cracks or the power loss.

[0042] In the technical solution of the present invention, by recording and experimenting on the dimensions, material properties, lamination width of different cells 100 and the comprehensive performance of the corresponding battery module, a relationship model for the upper limit of the lamination width of the battery module is established, that is, the width d of the overlapping area 200 satisfies the following relationship: d ≤ (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), and the comprehensive performance of the battery module is the best. Beyond this upper limit, the efficiency of the battery module drops sharply, and the comprehensive performance of the module cannot meet the factory standard. Through the above design of the relationship of the lamination width, when designing the lamination width of different cells 100, substituting the dimensions and material properties of the target cell 100 to be designed into the relationship model, the upper limit of the lamination width of the cell 100 that meets the best comprehensive performance of the target battery module can be designed. At the same time, by designing the overlapping width between the cells 100 through the above relationship model, it has the characteristics of fast design and high efficiency.

[0043] It can be understood that in the embodiment of the present application, since there is a partial overlap between the battery cells 100 in the battery assembly, it can be understood that the width d of the overlapping area in the first direction is at least greater than 0, that is, the width d of the overlapping area in the first direction is: 0 <d≤(L1-L2) / 2*tan θ + L1 / (L2*a*σ)。由此电池片之间的交叠距离可以在上述范围内进行选择,有助于产品版型设计过程中进行快速决策,能够保证电池组件的综合性能符合出厂标准。

[0044] It should be noted that, based on the relationship between the range of the cell stacking distance designed above and the light conversion efficiency of the cell assembly, within the range of d value greater than 0 and less than or equal to (L1-L2) / 2*tan θ + L1 / (L2*a*σ), the efficiency loss of the assembly caused by the partial shading of the cell 100 is more prominent, while the efficiency improvement caused by the increase in the proportion of the light-receiving area of the assembly due to the overlap of the cells is limited. Overall, the actual efficiency of the cell assembly is gradually decreasing. However, in this process, due to the increase in the stacking distance, the risk of hidden cracks in the assembly is reduced, which is reflected in the gradual increase in the yield rate of the assembly. For the evaluation of the influencing factors of the two, for example, the following evaluation model formula is used in this embodiment: (0.1*yield rate + 0.9*efficiency)*280 to evaluate the comprehensive performance of the assembly, thereby obtaining the optimal stacking distance solution in the embodiment of the present application. Of course, in other embodiments, based on different user needs, different production processes, and different product usage environments, the weight coefficient of the above evaluation model for the comprehensive performance of the assembly can also be adjusted in other ways, and this application does not limit this.

[0045] As an example, a set of data is given below to illustrate that the reasonable stacking range calculated by our stacking formula is between 0 and 1.14 mm. The specific parameters of the battery cell are as follows:

[0046]

[0047] The comprehensive scores of module efficiency and module yield for stacking distances within this range verified by our actual production data are shown in the following table (from the perspective of the light-receiving surface of the battery module, the chamfered edges of the battery cells are stacked on the cut edges of adjacent battery cells):

[0048]

[0049] The final test results showed that within the upper limit of the designed stacking distance, the comprehensive performance scores of the battery modules for the first five stacking distances were all above 80, indicating that the modules designed according to these five stacking distances all possessed high performance characteristics. When the stacking distance exceeded the upper limit of the design, the module efficiency dropped sharply, and the overall performance of the module failed to meet production requirements.

[0050] As Figure 3 and Figure 4 shown, in other embodiments, it may also be that the chamfered edges 101 of one of the two adjacent solar cells 100 overlap with the chamfered edges 101 of the other, and the cut edges 102 of one of the two adjacent solar cells 100 overlap with the cut edges 102 of the other. In this way, there are two types of overlapping ways of the two adjacent solar cells 100. In these two types of overlapping ways, the upper limit of the width of the above overlapping region 200 can also be applicable to the following relational expression: d ≤ (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), which is convenient for the layout design of the solar cell module.

[0051] In some embodiments, the chamfered edges 101 of the solar cell 100 are parallel to the cut edges 102 of the adjacent solar cell 100, and the distances between the edges of multiple solar cells 100 are equal. In another embodiment, the chamfered edges 101 of the solar cell 100 may also be arranged non - parallel to the cut edges 102 of the adjacent solar cell 100, that is to say, the chamfered edges 101 of the solar cell 100 may be slightly deflected relative to the cut edges 102 of the adjacent solar cell 100. At this time, the width d of the overlapping region 200 is the average lamination width between two adjacent solar cells 100.

[0052] Further, in the embodiments of the present application, the chamfered edges 101 of the solar cell 100 are stacked on the cut edges 102 of the adjacent solar cell 100. In this way, there is no suspended area below the chamfered edges 101 of the solar cell 100, and the cut edges 102 of the solar cell 100 can effectively support the chamfered edges 101 of the adjacent solar cell 100. During the lamination process of the solar cell module, the corners of the solar cell 100 are not easily cracked, further reducing the risk of hidden cracks in the solar cell module.

[0053] In some embodiments, the length of the chamfered edge 101 is L1, the length of the cut edge 102 is L2, the difference between L1 and L2 is greater than or equal to 1 mm and less than or equal to 10 mm. In such an embodiment, the range of the difference between the length L1 of the chamfered edge 101 and the length L2 of the cut edge 102 can be 1 mm, 2 mm, 3 mm, 5 mm, 7 mm, 8 mm, 9 mm, 10 mm or any value between 1 mm and 10 mm, and specific values are not limited herein.

[0054] In some embodiments, the range of the length of L1 is 150 mm to 250 mm. In such an embodiment, the length of L1 can be 150 mm, 180 mm, 190 mm, 200 mm, 220 mm, 230 mm, 240 mm, 250 mm or any value between 180 mm and 250 mm, and specific values are not limited herein.

[0055] In some embodiments, the length of L2 ranges from 140 mm to 240 mm. In such embodiments, the length of L2 can be 140 mm, 160 mm, 170 mm, 180 mm, 190 mm, 200 mm, 240 mm, or any value between 140 mm and 240 mm, and specific values are not limited herein.

[0056] In some embodiments, the angle θ of the chamfer of the cell 100 ranges from greater than 0 to less than π / 2. Further, the angle θ of the chamfer of the cell 100 ranges from 0.1 to 1.5, with the unit of rad. In such embodiments, the angle θ of the chamfer of the cell 100 can be 0.1, 0.2, 0.5, 0.7, 0.8, 1, 1.1, 1.2, 1.3, 1.4, 1.5, or any value between 0.1 and 1.5, and specific values are not limited herein. As Figure 1 shown, the angle θ of the chamfer mentioned in the embodiments of the present application is the included angle formed by the hypotenuse of the chamfer structure relative to the parallel line of the cutting edge.

[0057] In some embodiments, the structural strength σ of the cell 100 ranges from 20 to 300 Mpa. In such embodiments, the structural strength σ of the cell 100 can be 20 Mpa, 30 Mpa, 40 Mpa, 50 Mpa, 60 Mpa, 70 Mpa, 80 Mpa, 90 Mpa, 100 Mpa, 200 Mpa, 300 Mpa, or any value between 20 Mpa and 300 Mpa, and specific values are not limited herein.

[0058] In some embodiments, the thickness of the cell 100 ranges from 0.05 to 0.5 mm. In such embodiments, the thickness h of the cell 100 can be 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or any value between 0.05 mm and 0.5 mm, and specific values are not limited herein.

[0059] In some embodiments, each of the multiple overlapping regions has the same width in the first direction. Consistent overlapping width can reduce the resistance difference between different overlapping regions, make the current distribution more uniform, avoid the generation of local hot spots, thereby improving the overall component efficiency. And the unified overlapping width can reduce the processing complexity, improve the production consistency, reduce the assembly error caused by the overlapping size deviation, reduce the scrap rate, and save costs.

[0060] In other embodiments, the widths of the multiple overlapping regions 200 may vary regularly in a gradient manner in the first direction. Exemplarily, the multiple overlapping regions 200 include the nth overlapping region and the (n + 1)th overlapping region arranged along the first direction, and the width of the nth overlapping region is greater than the width of the (n + 1)th overlapping region, where n ≥ 1 and n is a positive integer. Of course, it can be understood that the widths of the overlapping regions that vary regularly in a gradient manner are also within the designed upper limit range. The gradient change in the overlapping width can disperse mechanical stress. For example, wider overlaps are designed in stress concentration regions (such as the edges of components) to enhance the fatigue resistance. In a vibrating or impact environment, the gradient design can absorb energy and transfer it step by step, reducing the risk of latent cracks. Alternatively, at least one of the widths of the multiple overlapping regions 200 is a first distance, and the widths of the remaining overlapping regions 200 are a second distance, where the first distance is greater than the second distance. This differential design of the overlapping regions 200 is particularly applicable to the design of patterns with special requirements for the overlapping distance of the solar cells near the ends of the battery string. For example, for some types of battery modules, multiple solar cells are connected in sequence to form a battery string. The width of the overlapping region formed between the solar cell closest to the end of the battery string and its adjacent solar cell is the first distance, and the overlapping distance between the remaining solar cells is the second distance, where the first distance is greater than the second distance. This can solve the problem of excessive offset during the lamination process of the solar cells located at the ends of the battery string.

[0061] In some embodiments, a photovoltaic system includes a battery module. In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground power plants, rooftop power plants, and water surface power plants, and can also be applied to devices or apparatuses that use solar energy for power generation, such as user solar power supplies, solar street lights, solar cars, and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this. That is to say, the photovoltaic system can be applied in all fields that require solar power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a busbar 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 arrays are connected to the busbar box, and the busbar box can collect the current generated by the photovoltaic arrays. The collected current flows through the inverter and is converted into alternating current required by the commercial power grid and then connected to the commercial power grid to achieve solar power supply.

[0062] In the description of this specification, the descriptions referring to terms such as "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0063] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a battery component, characterized in that, Including the following steps: A plurality of solar cells are sequentially and partially overlapped in a first direction to form a plurality of overlapping regions, wherein each of the solar cells includes a chamfered edge with a chamfer and a cut edge without a chamfer formed by cutting; According to the thickness of the cell and the length of the cut edge of the cell, based on the formula: σ = b / (L1*h 2 ) the structural strength σ of the cell is calculated, where b is a constant with a value of 620 mm -1 *Mpa -1 ; L1 is the length of the cut edge of the cell, in mm; h is the thickness of the cell, in mm; Based on the structural strength of the cell, the length of the cut edge of the cell, the length of the chamfered edge of the cell, and the chamfer angle of the cell, the range of the width d of the overlapping region is calculated according to the formula: d ≤ (L1 - L2) / 2 * tan θ + L1 / (L2 * a * σ), where L1 is the length of the cut edge of the cell, in mm; L2 is the length of the chamfered edge of the cell, in mm; θ is the chamfer angle of the cell, in rad; a is a correction factor, and a is 0.05 mm -1 *Mpa -1 ; σ is the structural strength of the cell, in Mpa.

2. The method for preparing a battery assembly according to claim 1, wherein, The length of the chamfered edge is L1, the length of the cut edge is L2, and the difference between L1 and L2 is greater than or equal to 1 mm and less than or equal to 10 mm.

3. The method for preparing a battery assembly according to claim 1, characterized in that, The length range of L1 is 150 mm to 250 mm.

4. The method for preparing a battery assembly according to claim 1, wherein, The length range of L2 is 140 mm to 240 mm.

5. The method for preparing a battery assembly according to claim 1, wherein, The angle θ of the chamfer of the solar cell ranges from greater than 0 and less than π / 2.

6. The method for preparing a battery assembly according to claim 1, wherein, The structural strength σ of the solar cell ranges from 20 to 300 Mpa.

7. The method for preparing a battery assembly according to claim 1, wherein The thickness range of the solar cell is 0.05 to 0.5 mm.

8. The method for preparing a battery assembly according to claim 1, wherein, The chamfered edges of the solar cells are stacked on the cut edges of adjacent solar cells.

9. The method for preparing a battery assembly according to claim 1, wherein Each of the plurality of overlapping regions has the same width in the first direction.

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