Back contact cell, back contact laminated cell and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic, in particular to a back contact cell, a back contact laminated cell and a photovoltaic module, the back contact cell comprises a substrate, main grids and mark points, the main grids and the mark points are arranged on the back surface of the substrate, the mark points are located on at least one side, close to the edge of the substrate, of the main grids, the main grids comprise first main grids and second main grids, and the first main grids and the second main grids are alternately arranged. The mark point is positioned on one side, close to the edge of the substrate, of the outermost main grid and is used for marking the polarity of the main grid adjacent to the mark point, so that an operator or an automatic visual system can quickly identify the polarity of the edge main grid, the polarity of other main grids can be conveniently inferred subsequently, the overall identification efficiency and the identification accuracy can be improved, and the identification efficiency and the identification accuracy can be improved. Therefore, the working efficiency in the production or maintenance process is improved, the production yield of the back contact battery, the battery string and the photovoltaic module is improved, the possibility of product scrapping caused by manual misoperation is reduced, the input cost of detection equipment is further reduced, and the actual production requirement is better met.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a back-contact cell, a back-contact stacked cell, and a photovoltaic module. Background Art

[0002] Back-contact photovoltaic cells are a type of photovoltaic cell technology that features positive and negative metal busbars located entirely on the backside of the cell. This leaves the front of the cell unobstructed by any metal busbars, maximizing the use of incident light, improving the cell's conversion efficiency, and enhancing the aesthetics of the photovoltaic module. However, in existing technologies, because the positive and negative metal busbars are located on the same side of the cell and arranged in a cross pattern, workers cannot quickly and accurately distinguish between the positive and negative busbars during use or maintenance, making assembly and maintenance of the cell more difficult. Summary of the Invention

[0003] In view of this, the present application provides a back-contact cell, a back-contact stacked cell and a photovoltaic module to solve the technical problem in the prior art that workers are unable to quickly and accurately distinguish the main grid properties.

[0004] The present application provides a back-contact battery, which includes a substrate, a main grid and a marking point. The main grid is arranged on the back side of the substrate, and the marking point is arranged on the back side of the substrate and is located on at least one side of the main grid close to the edge of the substrate.

[0005] The main grid includes a first main grid and a second main grid alternately arranged along the first direction x. Along the first direction x, the marking point is located on the side of the outermost main grid close to the edge of the substrate, and is used to mark the polarity of the main grid adjacent to the marking point.

[0006] The beneficial effect of the embodiments of the present application is that, by setting a marking point outside the main grid arrangement area, the operator or the automated visual system can quickly identify the edge main grid through the marking point, which is convenient for the subsequent inference of the polarity of the remaining main grids, and is beneficial to improving the overall recognition efficiency and recognition accuracy, thereby improving work efficiency during production or maintenance, and improving the production yield of back-contact cells, battery strings and photovoltaic modules, reducing the possibility of product scrapping due to human operational errors, and thereby reducing the investment cost of detection equipment, which is more in line with actual production needs.

[0007] In one possible embodiment, the back-contact battery further includes a fine grid, which includes a first fine grid and a second fine grid alternately arranged along the second direction y, one end of the first fine grid is connected to the first main grid, and the other end of the first fine grid is insulated from the second main grid by a first insulating glue, one end of the second fine grid is connected to the second main grid, and the other end of the second fine grid is insulated from the first main grid by a second insulating glue, and the first direction x is perpendicular to the second direction y.

[0008] Along the second direction y, the marking point covers at least two adjacent first insulating adhesives, or the marking point covers at least two adjacent second insulating adhesives.

[0009] In one possible embodiment, along the second direction y, a marking area is formed between the two outermost first insulating glues, and the marking point covers at least two adjacent first insulating glues within the marking area, or, a marking area is formed between the two outermost second insulating glues, and the marking point covers at least two adjacent second insulating glues within the marking area.

[0010] In a possible implementation, along the second direction y, the length of the marking point is a, the width of the insulating glue is d, and the ratio of a to d satisfies 3≤a / d≤15.

[0011] In a possible implementation, the marking point is made of the same material as the first insulating adhesive and the second insulating adhesive.

[0012] In a possible implementation, along the first direction x, the distance between the marking point and the edge of the substrate is L1, and L1 satisfies 0.2 mm ≤ L1 ≤ 3 mm.

[0013] In a possible implementation, along the second direction y, the length of the marking point is a, and a satisfies 0.8 mm ≤ a ≤ 3 mm; along the first direction x, the width of the marking point is b, and b satisfies 0.2 mm ≤ b ≤ 1 mm.

[0014] In a possible implementation, the shape of the marking point is one of a rectangle, a triangle, and an ellipse.

[0015] The present application also provides a back-contact stack cell, which includes a back-contact bottom cell and a perovskite top cell. The perovskite top cell is electrically connected to the front side of the back-contact bottom cell, and the back-contact bottom cell is the back-contact cell described in any one of the above items.

[0016] The beneficial effect of the embodiments of the present application is that the perovskite top cell can use a wide bandgap to absorb high-energy short-wavelength photons to reduce light loss and increase the open-circuit voltage, and the back-contact bottom cell can use a narrow bandgap to absorb low-energy long-wavelength photons to reduce photothermal loss and increase current density. Therefore, through the synergistic effect of the perovskite top cell and the back-contact bottom cell, the photoelectric conversion efficiency of the back-contact stack cell can be improved, thereby enabling the back-contact stack cell to utilize the solar spectrum in different bands to improve the overall photoelectric conversion efficiency.

[0017] The present application also provides a photovoltaic module, which includes any of the back-contact cells described above or the back-contact stacked cells described above.

[0018] The beneficial effects of the embodiments of the present application are as follows: a photovoltaic module includes a first cover plate, a first adhesive film, a cell layer, a second adhesive film, and a second cover plate stacked along its thickness direction; the cell layer includes multiple cell strings, each of which may include multiple back-contact cells or multiple back-contact stacked cells. Through this design approach, a photovoltaic module using back-contact cells or back-contact stacked cells can maximize the use of incident light to improve photoelectric conversion efficiency. It can also use wider and thicker metal electrodes on the back of the cell layer. By optimizing the electrode layout and interconnection method, it is beneficial to reduce series resistance and increase fill factor, thereby facilitating improved electrical performance of the photovoltaic module and enhancing the safety and reliability of the photovoltaic module during operation.

[0019] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 is a schematic structural diagram of a back contact battery provided in this application in one embodiment; Figure 2 yes Figure 1 A partial enlarged view of the middle I area; Figure 3 is a schematic structural diagram of another embodiment of a back-contact battery provided in this application; Figure 4 It is a schematic structural diagram of another embodiment of the back contact battery provided in this application.

[0022] Description of reference numerals: 1- Back contact battery; 11-base; 12- main grid; 121-first main grid; 122-second main grid; 13-marking points; 14-fine grid; 141-first fine grid; 142-second fine grid; 15-Insulation glue; 151-first insulating glue; 152-second insulating glue; 16-Marking area.

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0024] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0027] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0028] The embodiment of the present application provides a back contact battery, such as Figure 1 As shown, the back-contact battery 1 includes a substrate 11, a main grid 12 and a marking point 13. The main grid 12 is arranged on the back side of the substrate 11, and the marking point 13 is arranged on the back side of the substrate 11 and is located on at least one side of the main grid 12 close to the edge of the substrate 11.

[0029] Among them, the main gate 12 includes a first main gate 121 and a second main gate 122 arranged alternately along the first direction x. Along the first direction x, the marking point 13 is set on the side of the outermost main gate 12 close to the edge of the substrate 11, used to mark the polarity of the main gate 12 adjacent to the marking point 13.

[0030] It should be noted that in this application, the polarities of the first busbar 121 and the second busbar 122 are opposite, and the length direction of the substrate 11 is defined as the first direction x, and the width direction of the substrate 11 is defined as the second direction y.

[0031] In the embodiment of the present application, when the first main grid 121 and the second main grid 122 are arranged on the same side of the substrate 11, the substrate 11 can form a back contact battery 1 (Back Contact, BC), that is, the side of the substrate 11 on which the first main grid 121 and the second main grid 122 are arranged is the backlight surface of the back contact battery 1, and the side of the substrate 11 on which the first main grid 121 and the second main grid 122 are not arranged is the light-receiving surface of the back contact battery 1.

[0032] Through such a design, the light-receiving surface of the back-contact cell 1 will not be blocked by structures such as the first main grid 121 and the second main grid 122, so that it can be fully exposed to sunlight, thereby maximizing the light absorption area, which is beneficial to reducing optical losses and increasing short-circuit current.

[0033] The widths of the first main gate 121 and the second main gate 122 may be set to be wider to reduce series resistance and improve fill factor.

[0034] At the same time, the front surface field and good passivation effect of the back contact battery 1 are used to increase the gain of the open circuit voltage and the output power, so that the back contact battery 1 has a higher photoelectric conversion efficiency, thereby optimizing the working performance of the back contact battery 1 and improving product quality.

[0035] When the busbars 12 are arranged on the same side of the substrate 11 , along the arrangement direction of the busbars 12 , the marking point 13 can be set on the side of the outermost busbar 12 close to the edge of the substrate 11 to mark the polarity of the outermost busbar 12 .

[0036] Through such a design, the operator or the automated visual system can directly identify the polarity of the adjacent main grid 12 through the marking point 13, and can confirm the polarity of the main grid 12 without the need for detection equipment or subtle features, so as to achieve a rapid identification effect of the polarity of the edge main grid 12, which is conducive to simplifying the identification process, shortening the judgment time, and not causing confusion, thereby improving the work efficiency when producing or repairing the back contact battery 1.

[0037] Among them, the method of setting the marking points 13 on the substrate 11 has the characteristics of simple operation and easy implementation, which is conducive to the standardized setting of the marking points 13 to improve the coordination efficiency between various processes in the production process.

[0038] At the same time, by setting the marking point 13 on the side of the outermost main grid 12 close to the edge of the substrate 11 along the arrangement direction of the main grid 12, the marking point 13 can be close to the edge area of ​​the substrate 11 and away from the arrangement area of ​​the main grid 12, so that there is a clear boundary between the marking point 13 and the main grid 12, avoiding the risk of invalid recognition due to the large number and high distribution density of gate lines (including the main grid 12 and the fine grids connected to it) when the marking point 13 is located between adjacent main grids 12, which is beneficial to improving the recognition effect of the marking point 13 and ensuring the success rate and accuracy of recognition.

[0039] In addition, during the production or maintenance of back-contact cells 1, when the back-contact cells 1 are assembled manually, the risk of the operator reversing the polarity of adjacent back-contact cells 1 due to visual fatigue or negligence can be avoided, which is beneficial to improving the accuracy of the back-contact cells 1 during assembly, thereby reducing the possibility of internal short circuits, power losses, or even burning of battery strings or photovoltaic modules during operation, thereby ensuring the safety and reliability of battery strings or photovoltaic modules during operation.

[0040] Therefore, this embodiment sets a marking point 13 outside the main grid 12 arrangement area, so that the operator or the automated visual system can directly identify the polarity of the adjacent main grid 12 through the marking point 13, so as to achieve a rapid identification effect of the polarity of the edge main grid 12, and facilitate the subsequent inference of the polarity of the remaining main grids 12 in the main grid 12 arrangement area through alternating distribution, which is beneficial to improving the recognition efficiency and accuracy of the main grid 12 polarity, thereby improving the work efficiency of producing or maintaining the back contact battery 1, and further improving the production yield of the back contact battery 1, battery string and photovoltaic module, reducing the possibility of product scrapping due to manual operation errors, reducing the investment cost of detection equipment, and more in line with actual production needs.

[0041] In a specific embodiment, Figure 1 and Figure 2 As shown, the back-contact battery 1 also includes a fine grid 14 and an insulating glue 15, the insulating glue 15 includes a first insulating glue 151 and a second insulating glue 152, the fine grid 14 includes a first fine grid 141 and a second fine grid 142 alternately arranged along the second direction y, one end of the first fine grid 141 is connected to the first main grid 121, and the other end of the first fine grid 141 is insulated from the second main grid 122 by the first insulating glue 151, one end of the second fine grid 142 is connected to the second main grid 122, and the other end of the second fine grid 142 is insulated from the first main grid 121 by the second insulating glue 152, and the first direction x is perpendicular to the second direction y.

[0042] Along the second direction y, the marking point 13 covers at least two adjacent first insulating adhesives 151 , or the marking point 13 covers at least two adjacent second insulating adhesives 152 .

[0043] In the embodiment of the present application, since the polarities of the first main gate 121 and the second main gate 122 are opposite, the polarities of the first fine gate 141 and the second fine gate 142 are opposite, so that the first fine gate 141 and the second fine gate 142 are alternately arranged and spaced apart along the second direction y, one end of the first fine gate 141 is connected to the first main gate 121, and the other end of the first fine gate 141 extends along the first direction x toward the direction close to the second main gate 122 and is insulated from the second main gate 122 by the first insulating glue 151 to avoid contact between the two. Similarly, one end of the second fine gate 142 is connected to the second main gate 122, and the other end of the second fine gate 142 extends along the first direction x toward the direction close to the first main gate 121 and is insulated from the first main gate 121 by the second insulating glue 152 to avoid contact between the two.

[0044] This design allows the insulating adhesive 15 to reduce the likelihood of electrical connection between the first fine grid 141 and the second main grid 122, and between the second fine grid 142 and the first main grid 121. This reduces the likelihood of short circuits occurring during operation of the back-contact cell 1, thereby improving the safety and reliability of the back-contact cell 1, the cell string, and the photovoltaic module. Furthermore, after the insulating adhesive 15 is applied, the first fine grid 141 can extend close to the second main grid 122, and the second fine grid 142 can extend close to the first main grid 121. This allows the first fine grid 141 and the second fine grid 142 to be longer, thus increasing the range of current collection and improving the photoelectric conversion efficiency of the back-contact cell 1.

[0045] During the process of setting the marking points 13 , along the second direction y, the marking points 13 at least cover two adjacent first insulating adhesives 151 or two adjacent second insulating adhesives 152 .

[0046] Through such a design, the size of the marking point 13 along the second direction y is at least larger than the size of any insulating glue 15 along the second direction y, so that the marking point 13 has a larger coverage area, which is not only conducive to improving the accuracy and efficiency of the operator or the automated visual system in identifying the marking point 13, but also conducive to improving the stability and reliability of the connection between the marking point 13 and the substrate 11 and the insulating glue 15, reducing the possibility of the marking point 13 being offset during subsequent stacking and lamination processes, thereby avoiding the risk of the operator or the automated visual system being unable to identify and / or making an incorrect judgment, so as to further improve the recognition accuracy of the marking point 13 and the accuracy of the polarity judgment of the edge main grid 12.

[0047] Among them, by covering the marking point 13 on the substrate 11 and the insulating glue 15, the marking point 13 does not need to occupy part of the space on the substrate 11 alone, which can avoid interference with the fine grid 14 to affect the current transmission efficiency, reduce the impact of the marking point 13 on the working performance of the back contact battery 1, and increase the coverage area of ​​the fine grid 14 on the substrate 11, ensuring that the back contact battery 1 has a larger effective power generation area, which is beneficial to ensuring the safety and reliability of the back contact battery 1, battery string and photovoltaic module during operation.

[0048] In one possible embodiment, the marking point 13 is set to cover at least two adjacent first insulating glues 151 or two adjacent second insulating glues 152 along the second direction y, so that the marking point 13 can mark the polarity of the edge main grid 12 while also marking the polarity of the edge fine grid 14 within its coverage range, that is, along the second direction y, when the number of fine grids 14 covered by the marking point 13 is three, the polarity of the edge fine grid 14 within the coverage range can be marked, and the polarity of the middle fine grid 14 within the coverage range can also be marked. When the number of fine grids 14 covered by the marking point 13 is more than three, the polarity of the edge fine grid 14 within the coverage range can be marked.

[0049] Assume that the edge main grid 12 is the first main grid 121 and the marking point 13 marks the polarity of the first main grid 121 and the polarity of the edge fine grid 14 within its coverage area.

[0050] Along the first direction x, when the marking point 13 is set on the side of the first main grid 121 close to the edge of the substrate 11, along the second direction y, the marking point 13 covers two adjacent first insulating adhesives 151, so that the coverage range of the marking point 13 includes two first fine grids 141 and one second fine grid 142, and the second fine grid 142 is located between the two first fine grids 141. Therefore, when the marking point 13 marks the edge main grid 12 as positive (or negative), it can also mark the edge fine grid 14 within its coverage range as positive (or negative). Furthermore, when the feature of the marking point 13 is blurred due to defects or contamination, it is convenient for an operator or an automated vision system to first determine the polarity of the edge fine grid 14 within the coverage range based on the coverage range of the marking point 13, and then deduce the polarity of the main grid 12 connected to the edge fine grid 14.

[0051] Through such a design, the marking point 13 can have a dual marking function, that is, it can simultaneously mark the polarity of the edge main grid 12 and the polarity of the fine grid 14 connected to the edge main grid 12, which is conducive to improving the reliability and fault tolerance of the marking, further reducing the risk of misjudgment, and more in line with actual usage needs.

[0052] On this basis, the marking point 13 can also mark different polarities.

[0053] For example, along the first direction x, when the marking point 13 is set on the side of the first main grid 121 close to the edge of the substrate 11, along the second direction y, the marking point 13 covers two adjacent second insulating glues 152, so that the coverage range of the marking point 13 includes two second fine grids 142 and one first fine grid 141, and the first fine grid 141 is located between the two second fine grids 142, so that the marking point 13 can mark the edge main grid 12 as positive (or negative) while also marking the edge fine grid 14 within its coverage range as negative (or positive).

[0054] Therefore, when using the marking point 13 for double marking, the marking point 13 can mark two identical polarities at the same time, or it can mark two different polarities at the same time, which is beneficial to improve the flexibility of the marking point 13 during use, so that it can be adjusted according to different usage requirements.

[0055] In a specific embodiment, Figure 1 As shown, along the second direction y, a marking area 16 is formed between the two outermost first insulating glues 151, and the marking point 13 covers at least two adjacent first insulating glues 151 in the marking area 16, or a marking area 16 is formed between the two outermost second insulating glues 152, and the marking point 13 covers at least two adjacent second insulating glues 152 in the marking area 16.

[0056] In an embodiment of the present application, along the second direction y, a marking area 16 can be enclosed between the two outermost first insulating glues 151, and the marking point 13 covers at least two adjacent first insulating glues 151 in the marking area 16, so that there is a gap between the edge of the marking point 13 along the second direction y and the outermost first insulating glue 151. Similarly, along the second direction y, a marking area 16 can be enclosed between the two outermost second insulating glues 152, and the marking point 13 covers at least two adjacent second insulating glues 152 in the marking area 16, so that there is a gap between the edge of the marking point 13 along the second direction y and the outermost second insulating glue 152.

[0057] Through such a design approach, the risk of the marking point 13 being offset to the outside of the substrate 11 during the printing, stacking and / or lamination process can be avoided, which is conducive to improving the accuracy and reliability of printing, thereby reducing the risk of the marking point 13 exceeding the recognition range of the automated vision system and resulting in invalid recognition, thereby improving the efficiency and accuracy of recognition.

[0058] In one possible embodiment, the marking points 13 can be positioned near a corner region of the substrate 11, along the first direction x and the second direction y. The corner region is the angle between the long edge and the short edge of the substrate 11. Furthermore, when the back-contact cell 1 is provided with four marking points 13, the four marking points 13 can be distributed in the four corner regions of the substrate 11 to facilitate identification of the marking points 13 by an operator or an automated vision system from any angle or direction.

[0059] In a specific embodiment, Figure 2 As shown, along the second direction y, the length of the marking point 13 is a, the width of the insulating glue 15 is d, and the ratio of a to d satisfies 3≤a / d≤15.

[0060] In the embodiment of the present application, the size ratio of the marking point 13 to the insulating glue 15 along the second direction y can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.

[0061] When the size ratio of the marking point 13 and the insulating glue 15 along the second direction y is too small (for example, a / d is less than 3), the size of the marking point 13 along the second direction y is small, and the contact area between the marking point 13 and the substrate 11 and the insulating glue 15 is small, which not only easily affects the installation effect of the marking point 13, making it possible for the marking point 13 to be offset in the subsequent process, but also easily affects the recognition effect of the marking point 13 by the operator or the automated vision system, making it possible for the recognition process to be unrecognizable or to be misjudged, thereby causing the operator or the automated vision system to have a high error rate in judging the polarity of the edge main grid 12.

[0062] When the size ratio of the marking point 13 and the insulating glue 15 along the second direction y is too large (for example, a / d is greater than 15), the size of the marking point 13 along the second direction y is large, and the contact area between the marking point 13 and the substrate 11 and the insulating glue 15 is large, resulting in excessive input of production materials for printing the marking point 13, resulting in a higher production cost of the back contact battery 1.

[0063] Therefore, when the size ratio of the marking point 13 and the insulating glue 15 along the second direction y satisfies 3≤a / d≤15, the size of the marking point 13 along the second direction y is moderate, and the contact area between the marking point 13 and the substrate 11 and the insulating glue 15 is moderate, so that the marking point 13 has a high installation stability while being easy for the operator or the automated visual system to identify it, so as to improve the recognition accuracy and the accuracy of the judgment, which can not only ensure the safety and reliability of the back contact cell 1, the cell string and the photovoltaic module during operation, but also reduce the risk of excessive production costs due to excessive investment in production materials.

[0064] In a specific embodiment, the marking point 13 is made of the same material as the first insulating adhesive 151 and the second insulating adhesive 152 .

[0065] In the embodiment of the present application, since the marking point 13 can be covered on the substrate 11 and the insulating glue 15 at the same time, the material of the marking point 13 can be the same as the material of the insulating glue 15, so as to avoid the risk of electrical connection between the insulating glue 15 and the adjacent main grid 12 and / or fine grid 14, reduce the possibility of short circuit of the back contact cell 1 during operation, and improve the safety and reliability of the back contact cell 1, cell string and photovoltaic module during operation.

[0066] In the process of producing the back-contact battery 1, the marking point 13 can be fixed on the substrate 11 and the insulating glue 15 using the same process as the insulating glue 15, that is, the marking point 13 and the insulating glue 15 are both coated on the substrate 11 by printing, so as to simplify the overall process flow, improve production efficiency and reduce production costs.

[0067] Optionally, during the printing process, the marking point 13 can be coated on the substrate 11 and the insulating glue 15 using the same printing method after the insulating glue 15 is coated, so as to achieve simultaneous coverage of the substrate 11 and the insulating glue 15 by the marking point 13, thereby avoiding the risk of the insulating glue 15 blocking the marking point 13 and causing the operator or the automated vision system to be unable to effectively identify it, which is conducive to improving the accuracy of recognition and judgment, thereby ensuring the safety and reliability of the back-contact cell 1, cell string and photovoltaic module during operation.

[0068] In a specific embodiment, Figure 2 As shown, along the first direction x, the distance between the marking point 13 and the edge of the substrate 11 is L1, and L1 satisfies 0.2 mm ≤ L1 ≤ 3 mm.

[0069] In the embodiment of the present application, the distance between the marking point 13 and the edge of the substrate 11 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, etc.

[0070] When the distance between the marking point 13 and the edge of the substrate 11 is too small (for example, L1 is less than 0.2 mm), the marking point 13 is close to the edge of the substrate 11. In the subsequent processing of the back-contact battery 1 or the transportation of the back-contact battery 1, the edge of the back-contact battery 1 is easily contaminated or damaged, making the marking point 13 unclear or incomplete, resulting in the operator or the automated visual system being unable to identify it, and thus unable to determine the polarity of the edge main grid 12 through the marking point 13.

[0071] When the distance between the marking point 13 and the edge of the substrate 11 is too large (for example, L1 is greater than 3 mm), the marking point 13 is too far away from the edge of the substrate 11 and is close to the edge main grid 12, which can easily affect the recognition effect of the marking point 13 by the operator or the automated vision system, making it possible for the recognition process to be unrecognizable or to be misjudged, thereby causing the operator or the automated vision system to have a high error rate in judging the polarity of the edge main grid 12.

[0072] Therefore, when the distance between the marking point 13 and the edge of the substrate 11 satisfies 0.2mm≤L1≤3mm, the distance between the marking point 13 and the edge of the substrate 11 is moderate, and the distance between the marking point 13 and the edge main grid 12 is moderate, so that in the subsequent processing or transportation of the back contact battery 1, even if the edge of the back contact battery 1 is contaminated or damaged, it is not easy to affect the marking point 13, so as to ensure the recognition effect of the marking point 13 by the operator or the automated visual system, and improve the recognition accuracy and judgment accuracy.

[0073] In a specific embodiment, Figure 2 As shown, along the second direction y, the length of the marking point 13 is a, and a satisfies 0.8 mm ≤ a ≤ 3 mm.

[0074] In the embodiment of the present application, the length of the marking point 13 along the second direction y can be specifically 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1 .8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, 2.05mm, 2.1mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, 2.35mm, 2.4m m, 2.45mm, 2.5mm, 2.55mm, 2.6mm, 2.65mm, 2.7mm, 2.75mm, 2.8mm, 2.85mm, 2.9mm, 2.95mm, 3mm, etc.

[0075] When the length dimension of the marking point 13 along the second direction y is too small (for example, a is less than 0.8 mm), the contact area between the marking point 13 and the substrate 11 and the insulating glue 15 is small, which not only easily affects the installation effect of the marking point 13, making it possible for the marking point 13 to be offset in the subsequent process, but also easily affects the recognition effect of the marking point 13 by the operator or the automated visual system, making it possible for the recognition process to be unrecognizable or to be misjudged, thereby causing the operator or the automated visual system to have a higher error rate in judging the polarity of the edge main grid 12.

[0076] When the length of the marking point 13 along the second direction y is too large (for example, a is greater than 3 mm), the input amount of production materials of the marking point 13 is large, resulting in a higher production cost of the back contact battery 1.

[0077] Therefore, when the length dimension of the marking point 13 along the second direction y satisfies 0.8mm≤a≤3mm, the length dimension of the marking point 13 along the second direction y is moderate, and the contact area between the marking point 13 and the substrate 11 and the insulating glue 15 is moderate, so that the marking point 13 has a high installation stability while being easy for the operator or the automated visual system to identify it, so as to improve the recognition accuracy and the accuracy of the judgment, which can not only ensure the safety and reliability of the back contact cell 1, the cell string and the photovoltaic module during operation, but also reduce the risk of excessive production costs due to excessive investment in production materials.

[0078] In a specific embodiment, Figure 2 As shown, along the first direction x, the width of the marking point 13 is b, and b satisfies 0.2 mm ≤ b ≤ 1 mm.

[0079] In the embodiment of the present application, the width of the marking point 13 along the first direction x can be 0.2 mm, 0.22 mm, 0.24 mm, 0.26 mm, 0.28 mm, 0.3 mm, 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm, 0.5 mm, 0.52 mm, 0.54 mm, 0. 56mm, 0.58mm, 0.6mm, 0.62mm, 0.64mm, 0.66mm, 0.68mm, 0.7mm, 0.72mm, 0.74mm, 0.76mm, 0.7 8mm, 0.8mm, 0.82mm, 0.84mm, 0.86mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.96mm, 0.98mm, 1mm, etc.

[0080] When the width dimension of the marking point 13 along the first direction x is too small (for example, b is less than 0.2 mm), the contact area between the marking point 13 and the substrate 11 and the insulating glue 15 is small, which not only easily affects the installation effect of the marking point 13, making it possible for the marking point 13 to be offset in the subsequent process, but also easily affects the recognition effect of the marking point 13 by the operator or the automated vision system, making it possible for the recognition process to be unrecognizable or to be misjudged, thereby causing the operator or the automated vision system to have a higher error rate in judging the polarity of the edge main grid 12.

[0081] When the width of the marking point 13 along the first direction x is too large (for example, b is greater than 1 mm), the marking point 13 is close to the edge of the substrate 11 and is also close to the edge main grid 12, which can easily affect the recognition effect of the marking point 13 by the operator or the automated vision system, making it possible for the recognition process to be unrecognizable or to be misjudged, thereby causing the operator or the automated vision system to have a high error rate in judging the polarity of the edge main grid 12.

[0082] Therefore, when the width dimension of the marking point 13 along the first direction x satisfies 0.2mm≤b≤1mm, the distance between the marking point 13 and the edge of the substrate 11 is moderate, and the distance between the marking point 13 and the edge main grid 12 is moderate, so that in the subsequent processing or transportation of the back contact battery 1, even if the edge of the back contact battery 1 is contaminated or damaged, it is not easy to affect the marking point 13, so as to ensure the recognition effect of the marking point 13 by the operator or the automated visual system, and improve the recognition accuracy and judgment accuracy.

[0083] In a specific embodiment, Figure 1 、 Figure 3 and Figure 4 As shown, the shape of the marking point 13 is one of a rectangle, a triangle and an ellipse.

[0084] In the embodiment of the present application, since the first main grid 121 and the second main grid 122 are alternately arranged and spaced apart along the first direction x, the operator or the automated visual system can judge the polarity of the adjacent main grid 12 by the shape of the marking point 13, so that the operator or the automated visual system can directly identify the polarity of the adjacent main grid 12 by the shape characteristics of the marking point 13. It has the characteristics of simple operation and easy identification, and the polarity of the main grid 12 can be confirmed without the need for detection equipment or subtle features, so as to achieve a rapid identification effect of the polarity of the edge main grid 12, which is conducive to simplifying the identification process, shortening the judgment time, not easily causing confusion, and improving the work efficiency when producing or repairing the back contact battery 1.

[0085] For example, when the number of busbars 12 is an odd number, along the first direction x, the edge busbars 12 at the head end and the edge busbars 12 at the tail end have the same polarity. Therefore, a rectangular marking point 13 can be set on the side of one of the edge busbars 12 near the edge of the substrate 11 to mark the polarity of the edge busbar 12 as positive (or negative). This allows an operator or an automated vision system to directly determine that the polarity of the other edge busbar 12 is also positive (or negative) based on the rectangular marking point 13 and the number of busbars 12. This can reduce the number of marking points 13, thereby improving judgment efficiency and reducing production costs. Alternatively, rectangular marking points 13 can be set on the side of both edge busbars 12 near the edge of the substrate 11, so that an operator or an automated vision system can directly determine the polarity of the two edge busbars 12 based on the shape characteristics of the two marking points 13.

[0086] Alternatively, when the number of main grids 12 is an even number, along the first direction x, the polarity of the edge main grid 12 located at the head end and the polarity of the edge main grid 12 located at the end are opposite. Therefore, a rectangular marking point 13 can be set only on the side of one of the edge main grids 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative), and a triangular (or elliptical) marking point 13 can be set on the side of the other edge main grid 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as negative (or positive), so that the operator or the automated vision system can directly determine the polarity of the two edge main grids 12 through the shape characteristics of the two marking points 13.

[0087] In a specific embodiment, since the first main grid 121 and the second main grid 122 are alternately arranged and spaced apart along the first direction x, an operator or an automated visual system can also judge the polarity of the adjacent main grid 12 by the presence or absence of the marking point 13 .

[0088] When the number of busbars 12 is an odd number, along the first direction x, the edge busbars 12 at the head end and the edge busbars 12 at the tail end have the same polarity. Therefore, a marking point 13 can be set on the side of one of the edge busbars 12 close to the edge of the substrate 11 to mark the polarity of the edge busbar 12 as positive (or negative). This allows an operator or an automated vision system to directly determine that the polarity of the other edge busbar 12 is also positive (or negative) based on the marking point 13 and the number of busbars 12. This can reduce the number of marking points 13, thereby improving judgment efficiency and reducing production costs. Alternatively, marking points 13 can be set on the side of both edge busbars 12 close to the edge of the substrate 11 so that an operator or an automated vision system can directly determine the polarity of the two edge busbars 12 based on the two marking points 13.

[0089] When the number of main grids 12 is an even number, along the first direction x, the polarity of the edge main grid 12 located at the head end and the polarity of the edge main grid 12 located at the end end are opposite. Therefore, a marking point 13 can be set only on the side of one of the edge main grids 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative). This makes it easier for an operator or an automated visual system to directly determine whether the polarity of the other edge main grid 12 is negative (or positive) through the marking point 13 and the number of main grids 12, thereby reducing the number of marking points 13, which is beneficial to improving judgment efficiency and reducing production costs.

[0090] In a specific embodiment, since the first main grid 121 and the second main grid 122 are alternately arranged and spaced apart along the first direction x, an operator or an automated visual system can also judge the polarity of the adjacent main grid 12 by the size of the coverage area of ​​the marking point 13.

[0091] When the number of main grids 12 is an odd number, along the first direction x, the edge main grid 12 located at the head end and the edge main grid 12 located at the end have the same polarity. Therefore, marking points 13 with the same coverage area can be set on the side of the two edge main grids 12 close to the edge of the substrate 11 at the same time, so that the operator or the automated vision system can directly determine whether the polarity of the two edge main grids 12 is positive (or negative) based on the size of the coverage area of ​​the two marking points 13.

[0092] When the number of main grids 12 is an even number, along the first direction x, the polarity of the edge main grid 12 located at the head end and the polarity of the edge main grid 12 located at the end are opposite. Therefore, a marking point 13 with a larger coverage area can be set on the side of one of the edge main grids 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative), and a marking point 13 with a smaller coverage area can be set on the side of the other edge main grid 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as negative (or positive). This makes it easy for an operator or an automated visual system to directly determine the polarity of the two edge main grids 12 based on the size of the coverage area of ​​the two marking points 13.

[0093] An embodiment of the present application also provides a back-contact stack cell, which includes a back-contact bottom cell and a perovskite top cell, and the perovskite top cell is electrically connected to the front side of the back-contact bottom cell. The back-contact bottom cell is the back-contact cell 1 described in any one of the above items.

[0094] In an embodiment of the present application, when the front side of the perovskite top cell and the back-contact bottom cell are electrically connected to form a back-contact stacked cell, the solar spectrum can be utilized in different bands to improve the overall photoelectric conversion efficiency. That is, the perovskite top cell can use a wide band gap to absorb high-energy short-wavelength photons to reduce light loss and increase the open-circuit voltage, and the back-contact bottom cell can use a narrow band gap to absorb low-energy long-wavelength photons to reduce photothermal loss and increase current density, thereby improving the photoelectric conversion efficiency of the back-contact stacked cell through the synergistic effect of the perovskite top cell and the back-contact bottom cell.

[0095] At the same time, the back-contact stack cell also includes an interconnection layer, which is located between the perovskite top cell and the back-contact bottom cell along the thickness direction of the back-contact stack cell to connect and transmit current, which is conducive to achieving current matching between the two, and can reduce the series resistance and improve the fill factor to optimize the charge transfer efficiency.

[0096] An embodiment of the present application further provides a photovoltaic module, which includes the back-contact cell 1 described in any one of the above items or the back-contact stacked cell described in the above items.

[0097] In an embodiment of the present application, a photovoltaic module includes a first cover plate, a first adhesive film, a cell layer, a second adhesive film, and a second cover plate stacked along its thickness. The cell layer includes multiple cell strings, each of which may include multiple back-contact cells 1 or multiple back-contact stacked cells. This design allows a photovoltaic module using back-contact cells 1 or back-contact stacked cells to maximize the use of incident light to improve photoelectric conversion efficiency. It also enables the use of wider and thicker metal electrodes on the back of the cell layer. By optimizing the electrode layout and interconnection method, the series resistance is reduced and the fill factor is increased, thereby improving the electrical performance of the photovoltaic module and enhancing the safety and reliability of the photovoltaic module during operation.

[0098] The back contact battery 1 can be electrically connected in the form of a whole piece or multiple pieces to form multiple battery strings, and the multiple battery strings are electrically connected in series and / or parallel to form a battery layer. The back contact battery 1 includes but is not limited to an IBC battery (Interdigitated Back Contact Battery), an HBC battery (Heterojunction Back Contact Battery), a TBC battery (TOPCon Back Contact Battery), or an HPBC battery (Hybrid Passivated Back Contact Battery).

[0099] At the same time, the first cover plate is located on the side of the light-receiving surface of the cell layer, so that it can be ultra-white photovoltaic embossed glass or ultra-white processed float glass, etc., so that it has good light transmittance to ensure the photoelectric conversion efficiency of the photovoltaic module; the second cover plate is located on the side of the backlight surface of the cell layer, so that it can be rolled glass or ultra-white rolled glass, etc., so that it has good weather resistance to ensure the impact strength of the photovoltaic module.

[0100] In addition, the first adhesive film is located between the first cover plate and the light-receiving surface of the battery layer, and the second adhesive film is located between the second cover plate and the backlight surface of the battery layer, so as to fix the cover plate and the battery layer and isolate the battery layer from the external environment, so as to reduce the possibility of mechanical damage or chemical corrosion to the battery layer, ensure the reliability of the photovoltaic module during operation, and thus help to extend its service life. At least one of the first film and the second film can be an ethylene-vinyl acetate copolymer film (EVA film), a polyolefin elastomer film (POE film), a polyvinyl butyral film (PVB film) or a polyethylene terephthalate (PET) film, etc.; at least one of the first film and the second film can also be an EP film (a co-extruded film composed of stacked EVA films and POE films), an EPE film (a co-extruded film composed of stacked EVA films, POE films and EVA films) or a PVP film (a co-extruded film composed of stacked POE films, EVA films and POE films), etc.

[0101] The above describes in detail the structure, features and effects of the present application based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present application, but the present application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of the present application, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present application.

Claims

1. A back contact battery, characterized in that: The back contact battery comprises: substrate; a main grid, the main grid being arranged on the back side of the substrate; a marking point, the marking point being disposed on the back surface of the substrate and located on at least one side of the main grid close to an edge of the substrate; The main grid includes a first main grid and a second main grid alternately arranged along a first direction x. Along the first direction x, the marking point is located on the side of the outermost main grid close to the edge of the substrate, and is used to mark the polarity of the main grid adjacent to the marking point.

2. The back contact battery according to claim 1, characterized in that The back-contact battery further includes fine grids, the fine grids including first fine grids and second fine grids alternately arranged along a second direction y, one end of the first fine grid is connected to the first main grid, and the other end of the first fine grid is insulated from the second main grid by a first insulating adhesive, one end of the second fine grid is connected to the second main grid, and the other end of the second fine grid is insulated from the first main grid by a second insulating adhesive, and the first direction x is perpendicular to the second direction y; Along the second direction y, the marking point covers at least two adjacent first insulating adhesives, or the marking point covers at least two adjacent second insulating adhesives.

3. The back contact battery according to claim 2, characterized in that Along the second direction y, a marking area is formed between the two outermost first insulating glues, and the marking point covers at least two adjacent first insulating glues in the marking area, or a marking area is formed between the two outermost second insulating glues, and the marking point covers at least two adjacent second insulating glues in the marking area.

4. The back contact battery according to claim 2, characterized in that Along the second direction y, the length of the marking point is a, the width of the insulating glue is d, and the ratio of a to d satisfies 3≤a / d≤15.

5. The back contact battery according to claim 2, characterized in that The marking point is made of the same material as the first insulating glue and the second insulating glue.

6. The back contact cell according to any one of claims 1 to 5, characterized in that Along the first direction x, the distance between the marking point and the edge of the substrate is L1, and L1 satisfies 0.2 mm ≤ L1 ≤ 3 mm.

7. The back contact cell according to any one of claims 1 to 5, characterized in that Along the second direction y, the length of the marking point is a, and a satisfies 0.8mm≤a≤3mm; along the first direction x, the width of the marking point is b, and b satisfies 0.2mm≤b≤1mm.

8. The back contact cell according to any one of claims 1 to 5, characterized in that The shape of the marking point is one of a rectangle, a triangle and an ellipse.

9. A back contact stacked battery, characterized in that: The back-contact stack cell includes a back-contact bottom cell and a perovskite top cell, wherein the perovskite top cell is electrically connected to the front side of the back-contact bottom cell, and the back-contact bottom cell is the back-contact cell according to any one of claims 1 to 8.

10. A photovoltaic module, characterized in that: The photovoltaic module comprises the back-contact cell according to any one of claims 1 to 8 or the back-contact stacked cell according to claim 9.

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