A back contact cell, back contact laminate cell and photovoltaic module

Abstract

The application relates to the technical field of photovoltaics, and particularly relates to a back contact cell, a back contact laminated cell and a photovoltaic module. The back contact cell comprises a substrate, a main grid and a mark point. The main grid and the mark point are arranged on the back surface of the substrate. The mark point is located on at least one side of the main grid close to the edge of the substrate. The main grid comprises first main grids and second main grids arranged alternately. The mark point is located on the side of the outermost main grid close to the edge of the substrate, and is used for marking the polarity of the main grid adjacent to the mark point, so that the operator or the automatic visual system can quickly identify the polarity of the edge main grid, the polarity of the remaining main grids can be inferred subsequently, the identification efficiency and the identification accuracy of the whole are improved, the work efficiency in the production or maintenance process is improved, the production yield of the back contact cell, the cell string and the photovoltaic module is improved, the possibility of product scrapping caused by manual operation errors is reduced, the investment cost of the detection equipment is reduced, and the actual production demand is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a back contact cell, a back contact laminated cell and a photovoltaic module. BACKGROUND

[0002] The back contact cell is a kind of photovoltaic cell technology, in which the positive and negative metal grid lines are all designed on the back of the cell sheet, and the front of the cell sheet is not blocked by any metal grid line, so as to maximize the use of incident light, improve the conversion efficiency of the cell and improve the appearance of the photovoltaic module. However, in the prior art, since the positive and negative metal grid lines are located on the same side of the cell sheet and are arranged in cross, the operator cannot quickly and accurately distinguish the polarity of the positive and negative main grids during use or maintenance, thereby causing high difficulty in assembling and repairing the cell sheet. SUMMARY

[0003] Therefore, the present application provides a back contact cell, a back contact laminated cell and a photovoltaic module to solve the technical problem that the operator cannot quickly and accurately distinguish the polarity of the main grid in the prior art.

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

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

[0006] The present application has the beneficial effects that, by arranging the mark point outside the main grid arrangement area, the operator or the automatic visual system can quickly identify the polarity of the edge main grid through the mark point, which is convenient for subsequent inference of the polarity of the remaining main grids, and is conducive to improving the identification efficiency and accuracy of the whole, thereby improving the work efficiency in the production or maintenance process, improving the production yield of the back contact cell, the cell string and the photovoltaic module, reducing the possibility of product scrapping caused by human operation errors, and further reducing the investment cost of detection equipment, which is more in line with the actual production demand.

[0007] In a possible implementation, the back contact cell further comprises a fine grid, the fine grid comprises first fine grids and second fine grids arranged alternately along a second direction y, one end of the first fine grid is connected with the first main grid, 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 with 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.

[0008] In 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 a possible implementation, in the second direction y, a marking area is formed between the two outermost first insulating adhesives, and the marking point covers at least two adjacent first insulating adhesives in the marking area, or a marking area is formed between the two outermost second insulating adhesives, and the marking point covers at least two adjacent second insulating adhesives in the marking area.

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

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

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

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

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

[0015] The application further provides a back contact stacked cell, which comprises a back contact bottom cell and a perovskite top cell, the perovskite top cell is electrically connected to the front surface of the back contact bottom cell, and the back contact bottom cell is the back contact cell described in any one of the above.

[0016] The perovskite top cell can absorb high-energy short-wavelength photons to reduce light loss and improve open-circuit voltage, and the back contact bottom cell can absorb low-energy long-wavelength photons to reduce light-heat loss and improve current density, so that the photovoltaic conversion efficiency of the back contact stacked cell can be improved through the synergistic effect of the perovskite top cell and the back contact bottom cell, and the overall photovoltaic conversion efficiency of the back contact stacked cell can be improved through the use of the solar spectrum in different wave bands.

[0017] The application further provides a photovoltaic module, which comprises the back contact cell described in any one of the above or the back contact stacked cell described above.

[0018] The photovoltaic module includes a first cover plate, a first adhesive film, a cell piece layer, a second adhesive film and a second cover plate which are stacked along the thickness direction of the photovoltaic module. The cell piece layer includes a plurality of cell strings. Each cell string can include a plurality of back contact cells or a plurality of back contact stacked cells. By the design, the photovoltaic module using the back contact cells or the back contact stacked cells can maximize the use of incident light to improve the photoelectric conversion efficiency. In addition, a wider and thicker metal electrode can be used on the back of the cell piece layer. By optimizing the electrode layout and interconnection mode, the series resistance can be reduced, the fill factor can be improved, and thus the electrical performance of the photovoltaic module can be improved, and the safety and reliability of the photovoltaic module during operation can be improved.

[0019] It should be understood that the above general description and the following detailed description are only exemplary and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a structural schematic diagram of the back contact cell provided by the present application in an embodiment;

[0022] Figure 2 is Figure 1 is a partial enlarged view of the I region in

[0023] Figure 3 is a structural schematic diagram of the back contact cell provided by the present application in another embodiment;

[0024] Figure 4 is a structural schematic diagram of the back contact cell provided by the present application in another embodiment.

[0025] Explanation of reference signs:

[0026] 1-back contact cell;

[0027] 11-substrate;

[0028] 12-main grid;

[0029] 121-first main grid;

[0030] 122-second main grid;

[0031] 13-marking point;

[0032] 14-fine grid;

[0033] 141 - first fine grid;

[0034] 142 - second fine grid;

[0035] 15 - insulating glue;

[0036] 151 - first insulating glue;

[0037] 152 - second insulating glue;

[0038] 16 - marking area.

[0039] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application. DETAILED DESCRIPTION

[0040] For a better understanding of the technical solutions of the present application, the embodiments of the present application are described in detail below with reference to the drawings.

[0041] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0042] The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0043] It should be understood that the term "and / or" used herein is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0044] The embodiments of the present application provide 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 of the substrate 11, and the marking point 13 is arranged on the back of the substrate 11 and located on at least one side of the main grid 12 close to the edge of the substrate 11.

[0045] Among them, the main grid 12 includes first main grid 121 and second main grid 122 arranged alternately along the first direction x, along the first direction x, the marking point 13 is arranged on the side of the outermost main grid 12 close to the edge of the substrate 11, for marking the polarity of the main grid 12 adjacent to the marking point 13.

[0046] It should be noted that the polarity of the first main grid 121 and the second main grid 122 is opposite in the present application, 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.

[0047] 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 where the first main grid 121 and the second main grid 122 are arranged is the back light surface of the back contact battery 1, and the side of the substrate 11 where 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.

[0048] Through such a design, the light receiving surface of the back contact battery 1 will not be blocked by the structures such as the first main grid 121 and the second main grid 122, so that it can be completely exposed to sunlight, thereby realizing the maximum setting of the light absorption area, which is beneficial to reduce optical loss and improve short-circuit current.

[0049] Among them, the width size of the first main grid 121 and the second main grid 122 can be set wider to reduce the series resistance and improve the fill factor.

[0050] At the same time, through the front surface field of the back contact battery 1 and the good passivation effect, the gain of the open circuit voltage is improved, and the output power is improved, 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 the product quality.

[0051] When the main grid 12 is arranged on the same side of the substrate 11, along the arrangement direction of the main grid 12, the marking point 13 can be arranged on the side close to the edge of the substrate 11 of the outermost main grid 12, for marking the polarity of the outermost main grid 12.

[0052] Through such a design, the operator or the automatic visual system can directly identify the polarity of the adjacent main grid 12 through the marking point 13, without the need for detection equipment or fine features to confirm the polarity of the main grid 12, so as to realize the rapid identification effect of the edge main grid 12 polarity, which is beneficial to simplify the identification process, shorten the judgment time, and not easy to cause confusion, and improve the working efficiency during the production or maintenance of the back contact battery 1.

[0053] Among them, the marking point 13 arranged on the substrate 11 has the characteristics of simple operation and easy implementation, which is beneficial to realize the standardized setting of the marking point 13, so as to improve the cooperation efficiency between the processes in the production process.

[0054] Meanwhile, by arranging the marking point 13 at the outermost side of the main grid 12 close to the edge of the base 11, the marking point 13 can be close to the edge of the base 11 and away from the arrangement area of the main grid 12, so that the marking point 13 and the main grid 12 have a clear boundary, avoiding the risk of invalid identification due to the large number and high distribution density of grid lines (including the main grid 12 and the fine grid connected thereto) when the marking point 13 is located between adjacent main grids 12, which is beneficial to improve the identification effect of the marking point 13 and ensure the success rate and accuracy of identification.

[0055] In addition, during the production or maintenance of the back contact battery 1, when the back contact battery 1 is assembled manually, the risk of reverse polarity of adjacent back contact batteries 1 due to visual fatigue or negligence of the operator can be avoided, which is beneficial to improve the accuracy of the back contact battery 1 during assembly, thereby reducing the possibility of internal short circuit, power loss, or even burning of the battery string or photovoltaic module during work, and further ensuring the safety and reliability of the battery string or photovoltaic module during work.

[0056] Therefore, by arranging the marking point 13 outside the arrangement area of the main grid 12, the operator or the automatic visual system can directly identify the polarity of the adjacent main grid 12 through the marking point 13, so as to realize the rapid identification of the polarity of the edge main grid 12, which is convenient for subsequent inference of the polarity of the remaining main grids 12 in the arrangement area of the main grid 12, and is beneficial to improve the identification efficiency and accuracy of the polarity of the main grid 12, thereby improving the work efficiency of the production or maintenance of the back contact battery 1, and further improving the production yield of the back contact battery 1, the battery string, and the photovoltaic module, reducing the possibility of product scrapping due to manual operation errors, reducing the investment cost of detection equipment, and more meeting the actual production needs.

[0057] In a specific embodiment, as shown in Figure 1 and Figure 2 The back contact battery 1 further 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 arranged alternately along a second direction y, one end of the first fine grid 141 is connected with the first main grid 121, 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 with the second main grid 122, 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.

[0058] 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.

[0059] In the embodiment of the present application, since the polarities of the first main grid 121 and the second main grid 122 are opposite, the polarities of the first fine grid 141 and the second fine grid 142 are opposite, so that the first fine grid 141 and the second fine grid 142 are alternately arranged and spaced apart 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 extends in the direction close to the second main grid 122 along the first direction x and is insulated from the second main grid 122 by the first insulating adhesive 151 to avoid contact between them. Similarly, 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 extends in the direction close to the first main grid 121 along the first direction x and is insulated from the first main grid 121 by the second insulating adhesive 152 to avoid contact between them.

[0060] Through such a design, the insulating adhesive 15 can reduce the possibility of electrical connection between the first fine grid 141 and the second main grid 122 and the electrical connection between the second fine grid 142 and the first main grid 121, thereby reducing the possibility of short circuit of the back contact battery 1 during operation, and further improving the safety and reliability of the back contact battery 1, the battery string and the photovoltaic module during operation. And after setting the insulating adhesive 15, the first fine grid 141 can extend to a position close to the second main grid 122, and the second fine grid 142 can extend to a position close to the first main grid 121, so that the length of the first fine grid 141 and the second fine grid 142 is longer, and the range of collecting current is larger, thereby improving the photoelectric conversion efficiency of the back contact battery 1.

[0061] In the process of setting the marking point 13, along the second direction y, the marking point 13 covers at least two adjacent first insulating adhesives 151 or two adjacent second insulating adhesives 152.

[0062] Through such a design, the size of the marking point 13 along the second direction y is at least greater than the size of any insulating adhesive 15 along the second direction y, so that the marking point 13 has a larger coverage area, which not only helps to improve the accuracy and efficiency of the operator or the automatic visual system in identifying the marking point 13, but also helps to improve the stability and reliability of the connection between the marking point 13 and the substrate 11 and the insulating adhesive 15, reduce the possibility of the marking point 13 shifting in the subsequent layering and lamination process, and further avoid the risk of the operator or the automatic visual system being unable to identify and / or misjudging, so as to further improve the identification accuracy of the marking point 13 and the accuracy of the polarity judgment of the edge main grid 12.

[0063] The mark point 13 is overlaid on the base 11 and the insulating glue 15, so that the mark point 13 does not need to occupy a part of space on the base 11 alone, can avoid interference with the fine grid 14 to affect the transmission efficiency of the current, reduce the influence of the mark point 13 on the working performance of the back contact battery 1, and can increase the coverage area of the fine grid 14 on the base 11, so as to ensure that the back contact battery 1, the battery string and the photovoltaic module have high safety and reliability during work.

[0064] In a possible implementation, the mark point 13 covers at least two adjacent first insulating glues 151 or two adjacent second insulating glues 152 along the second direction y, so that the mark point 13 can mark the polarity of the edge fine grid 14 in the coverage range while marking the polarity of the edge main grid 12, that is, along the second direction y, when the mark point 13 covers three fine grids 14, the polarity of the edge fine grid 14 in the coverage range can be marked, and the polarity of the middle fine grid 14 in the coverage range can also be marked, and when the mark point 13 covers more than three fine grids 14, the polarity of the edge fine grid 14 in the coverage range can be marked.

[0065] Taking the edge main grid 12 as the first main grid 121 and the mark point 13 marking the polarity of the first main grid 121 and the polarity of the edge fine grid 14 in the coverage range as an example.

[0066] Along the first direction x, when the mark point 13 is arranged on one side of the first main grid 121 close to the edge of the base 11, along the second direction y, the mark point 13 covers two adjacent first insulating glues 151, so that the coverage range of the mark 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, so that the mark point 13 can mark the edge fine grid 14 in the coverage range as positive (or negative) when the edge main grid 12 is positive (or negative), and further, in the case that the feature of the mark point 13 is blurred due to defects or pollution, the operator or the automatic visual system can first judge the polarity of the edge fine grid 14 in the coverage range according to the coverage range of the mark point 13, and then deduce the polarity of the main grid 12 connected with the edge fine grid 14.

[0067] Through such a design, the mark point 13 can have a dual marking function, that is, marking the polarity of the edge main grid 12 and the polarity of the fine grid 14 connected with the edge main grid 12 at the same time, which is conducive to improving the reliability and fault tolerance of marking, further reducing the risk of judgment errors, and more meeting the actual use requirements.

[0068] On this basis, the mark point 13 can also mark different polarities.

[0069] For example, along the first direction x, when the marking point 13 is arranged at one 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 glue 152, so that the marking point 13 covers 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 fine grid 14 as negative (or positive) when the marking edge main grid 12 is positive (or negative).

[0070] Therefore, when the marking point 13 is used for double marking, the marking point 13 can mark two same polarities at the same time, or mark two different polarities at the same time, which is beneficial to improve the flexibility of the marking point 13 in use, so as to be adjusted according to different use requirements.

[0071] In a specific embodiment, as shown in Figure 1 along the second direction y, the marking area 16 is formed between the two outermost first insulating glue 151, and the marking point 13 covers at least two adjacent first insulating glue 151 in the marking area 16, or the marking area 16 is formed between the two outermost second insulating glue 152, and the marking point 13 covers at least two adjacent second insulating glue 152 in the marking area 16.

[0072] In the embodiment of the application, along the second direction y, the marking area 16 can be formed between the two outermost first insulating glue 151, and the marking point 13 covers at least two adjacent first insulating glue 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, the marking area 16 can be formed between the two outermost second insulating glue 152, and the marking point 13 covers at least two adjacent second insulating glue 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.

[0073] Through such a design, the risk of the marking point 13 deviating to the outside of the substrate 11 during printing, stacking and / or laminating can be avoided, which is beneficial to improve the accuracy and reliability during printing, so as to reduce the risk that the marking point 13 exceeds the recognition range of the automatic visual system and leads to invalid recognition, and further improve the efficiency and accuracy of recognition.

[0074] In a possible implementation, the marking points 13 can be arranged near the corner regions of the substrate 11, which are the corners of the long edges and the short edges of the substrate 11, along the first direction x and the second direction y. When the back contact battery 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, so as to facilitate the operator or the automatic visual system to recognize the marking points 13 from any angle or direction.

[0075] In a specific implementation, as shown in FIG. 2, along the second direction y, the length of the marking point 13 is a, and the width of the insulating adhesive 15 is d, and the ratio of a to d satisfies 3≤a / d≤15. Figure 2

[0076] In the embodiments of the present application, the ratio of the size of the marking point 13 to the size of the insulating adhesive 15 along the second direction y can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.

[0077] When the ratio of the size of the marking point 13 to the size of the insulating adhesive 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 adhesive 15 is small, which not only affects the installation effect of the marking point 13, and makes the marking point 13 have the possibility of deviation in the subsequent process, but also affects the recognition effect of the operator or the automatic visual system on the marking point 13, and makes the operator or the automatic visual system have the possibility of not recognizing or misjudging in the recognition process, thereby increasing the error rate of the operator or the automatic visual system in judging the polarity of the edge main grid 12.

[0078] When the ratio of the size of the marking point 13 to the size of the insulating adhesive 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 adhesive 15 is large, which causes the production cost of the back contact battery 1 to be high due to the excessive input of production materials for printing the marking point 13.

[0079] Therefore, when the ratio of the size of the marking point 13 to the size of the insulating adhesive 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 adhesive 15 is moderate, so as to facilitate the operator or the automatic visual system to recognize the marking point 13 while the marking point 13 has high installation stability, thereby improving the recognition accuracy and judgment accuracy, not only ensuring the safety and reliability of the back contact battery 1, the battery string and the photovoltaic module in the working process, but also avoiding the risk of high production cost caused by excessive input of production materials.

[0080] ​In a specific embodiment, the marking point 13 is made of the same material as the first insulating glue 151 and the second insulating glue 152.

[0081] In the embodiments of the present application, since the marking point 13 can be simultaneously applied on the substrate 11 and the insulating glue 15, the material of the marking point 13 can be the same as that 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 the fine grid 14, reduce the possibility of short circuit of the back contact battery 1 during operation, and improve the safety and reliability of the back contact battery 1, the battery string and the photovoltaic module during operation.

[0082] In addition, in the process of producing the back contact battery 1, the marking point 13 and the insulating glue 15 can be fixed on the substrate 11 and the insulating glue 15 by the same process, that is, the marking point 13 and the insulating glue 15 are both applied on the substrate 11 by printing, so as to simplify the overall process flow, improve the production efficiency and reduce the production cost.

[0083] Optionally, in the printing process, the marking point 13 can be applied on the substrate 11 and the insulating glue 15 by the same printing method after the insulating glue 15 is applied, so as to realize the simultaneous covering of the marking point 13 on the substrate 11 and the insulating glue 15, avoid the risk that the insulating glue 15 blocks the marking point 13 and causes the operator or the automatic visual system to fail to effectively identify, and be beneficial to improve the identification accuracy and the judgment accuracy, so as to ensure the safety and reliability of the back contact battery 1, the battery string and the photovoltaic module during operation.

[0084] In a specific embodiment, as shown in Figure 2 In a specific embodiment, the distance between the marking point 13 and the edge of the substrate 11 along the first direction x is L1, and L1 satisfies 0.2mm≤L1≤3mm.

[0085] In the embodiments 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.

[0086] 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 too close to the edge of the substrate 11, and in subsequent processing of the back contact battery 1 or in subsequent transportation of the back contact battery 1, the edge of the back contact battery 1 is easily contaminated or damaged, so that the marking point 13 is not clear or complete, and the operator or the automatic vision system cannot identify the marking point 13, and thus cannot determine the polarity of the edge main grid 12 through the marking point 13.

[0087] 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 too close to the edge main grid 12, which easily affects the identification of the marking point 13 by the operator or the automatic vision system, and there is a possibility that the identification process cannot be identified or misjudged, and thus the error rate of the operator or the automatic vision system in determining the polarity of the edge main grid 12 is high.

[0088] Therefore, when the distance between the marking point 13 and the edge of the substrate 11 satisfies 0.2 mm≤L1≤3 mm, 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 subsequent processing or transportation of the back contact battery 1, even if the edge of the back contact battery 1 is contaminated or damaged, the marking point 13 is not easily affected, so as to ensure the identification effect of the marking point 13 by the operator or the automatic vision system, and improve the identification accuracy and the judgment accuracy.

[0089] In a specific embodiment, as shown in FIG. 2, along the second direction y, the length of the marking point 13 is a, and a satisfies 0.8 mm≤a≤3 mm. Figure 2

[0090] In the embodiment of the present application, the length of the marking point 13 along the second direction y can be 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, 1.5 mm, 1.55 mm, 1.6 mm, 1.65 mm, 1.7 mm, 1.75 mm, 1.8 mm, 1.85 mm, 1.9 mm, 1.95 mm, 2 mm, 2.05 mm, 2.1 mm, 2.15 mm, 2.2 mm, 2.25 mm, 2.3 mm, 2.35 mm, 2.4 mm, 2.45 mm, 2.5 mm, 2.55 mm, 2.6 mm, 2.65 mm, 2.7 mm, 2.75 mm, 2.8 mm, 2.85 mm, 2.9 mm, 2.95 mm, 3 mm, etc. ​

[0091] When the length dimension of the mark point 13 along the second direction y is too small (for example, a is less than 0.8 mm), the contact area between the mark point 13 and the substrate 11 and the insulating adhesive 15 is small, which not only affects the installation effect of the mark point 13, so that the mark point 13 has the possibility of deviation in the subsequent process, but also affects the recognition effect of the mark point 13 by the operator or the automatic visual system, so that there is the possibility of misrecognition or misjudgment in the recognition process, and then the error rate of the operator or the automatic visual system in judging the polarity of the edge main grid 12 is high.

[0092] When the length dimension of the mark point 13 along the second direction y is too large (for example, a is greater than 3 mm), the input amount of the production material of the mark point 13 is large, which leads to a high production cost of the back contact battery 1.

[0093] Therefore, when the length dimension of the mark point 13 along the second direction y satisfies 0.8 mm≤a≤3 mm, the length dimension of the mark point 13 along the second direction y is moderate, the contact area between the mark point 13 and the substrate 11 and the insulating adhesive 15 is moderate, so that the mark point 13 has high installation stability and is convenient for the operator or the automatic visual system to recognize, so as to improve the recognition accuracy and judgment accuracy, which not only guarantees the safety and reliability of the back contact battery 1, the battery string and the photovoltaic module in the working process, but also avoids the risk of high production cost caused by too much input of production material.

[0094] In a specific embodiment, as shown in FIG. 1, Figure 2 the width of the mark point 13 along the first direction x is b, and b satisfies 0.2 mm≤b≤1 mm.

[0095] In the embodiment of the application, the width dimension of the mark point 13 along the first direction x can be specifically 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, 0.56 mm, 0.58 mm, 0.6 mm, 0.62 mm, 0.64 mm, 0.66 mm, 0.68 mm, 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, 0.82 mm, 0.84 mm, 0.86 mm, 0.88 mm, 0.9 mm, 0.92 mm, 0.94 mm, 0.96 mm, 0.98 mm, 1 mm, etc.

[0096] When the width dimension of the mark point 13 along the first direction x is too small (for example, b is less than 0.2 mm), the contact area between the mark point 13 and the substrate 11 and the insulating adhesive 15 is small, which not only easily affects the installation effect of the mark point 13, so that the mark point 13 has the possibility of deviation in the subsequent process, but also easily affects the recognition effect of the mark point 13 by the operator or the automatic visual system, so that there is the possibility of misrecognition or misjudgment in the recognition process, and then the error rate of the operator or the automatic visual system in judging the polarity of the edge main grid 12 is high.

[0097] When the width dimension of the mark point 13 along the first direction x is too large (for example, b is greater than 1 mm), the mark point 13 is close to the edge of the substrate 11 and close to the edge main grid 12, which easily affects the recognition effect of the mark point 13 by the operator or the automatic visual system, so that there is the possibility of misrecognition or misjudgment in the recognition process, and then the error rate of the operator or the automatic visual system in judging the polarity of the edge main grid 12 is high.

[0098] Therefore, when the width dimension of the mark point 13 along the first direction x satisfies 0.2 mm≤b≤1 mm, the distance between the mark point 13 and the edge of the substrate 11 is moderate, and the distance between the mark point 13 and the edge main grid 12 is moderate, so that even if the edge of the back contact battery 1 is contaminated or damaged in the subsequent process of processing or transporting the back contact battery 1, the mark point 13 is not easily affected, so as to protect the recognition effect of the mark point 13 by the operator or the automatic visual system, improve the recognition accuracy and the judgment accuracy.

[0099] In a specific embodiment, as shown in Figure 1 , Figure 3 and Figure 4 , the shape of the mark point 13 is one of a rectangle, a triangle and an ellipse.

[0100] In the embodiment of the application, since the first main grid 121 and the second main grid 122 are alternately arranged and spaced along the first direction x, the operator or the automatic visual system can judge the polarity of the main grid 12 adjacent to the mark point 13 through the shape of the mark point 13, so that the operator or the automatic visual system can directly recognize the polarity of the main grid 12 adjacent to the mark point 13 through the shape characteristics of the mark point 13, which has the characteristics of simple operation and easy recognition, and the polarity of the main grid 12 can be confirmed without the detection equipment or the fine features, so as to realize the rapid recognition effect of the polarity of the edge main grid 12, which is beneficial to simplify the recognition process, shorten the judgment time, not easily cause confusion, and improve the work efficiency during the production or maintenance of the back contact battery 1.

[0101] For example, when the number of the main grids 12 is odd, along the first direction x, the polarities of the edge main grid 12 at the first end and the edge main grid 12 at the last end are the same, thus a rectangular mark point 13 can be arranged on one side of the edge main grid 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative), so that the operator or the automatic visual system can directly determine that the polarity of the other edge main grid 12 is also positive (or negative) through the rectangular mark point 13 and the number of the main grids 12, thereby reducing the number of mark points 13, which is conducive to improving the judgment efficiency and reducing the production cost. Alternatively, rectangular mark points 13 can also be arranged on the sides of both edge main grids 12 close to the edge of the substrate 11, so that the operator or the automatic visual system can directly determine the polarities of the two edge main grids 12 through the shape features of the two mark points 13.

[0102] Alternatively, when the number of the main grids 12 is even, along the first direction x, the polarities of the edge main grid 12 at the first end and the edge main grid 12 at the last end are opposite, thus a rectangular mark point 13 can be arranged on one side of one edge main grid 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) mark point 13 can be arranged on one 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 automatic visual system can directly determine the polarities of the two edge main grids 12 through the shape features of the two mark points 13.

[0103] 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, the operator or the automatic visual system can also determine the polarity of the main grid 12 adjacent to the mark point 13 through the presence or absence of the mark point 13.

[0104] When the number of the main grids 12 is odd, along the first direction x, the polarities of the edge main grid 12 at the first end and the edge main grid 12 at the last end are the same, thus a mark point 13 can be arranged on one side of the edge main grid 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative), so that the operator or the automatic visual system can directly determine that the polarity of the other edge main grid 12 is also positive (or negative) through the mark point 13 and the number of the main grids 12, thereby reducing the number of mark points 13, which is conducive to improving the judgment efficiency and reducing the production cost. Alternatively, mark points 13 can also be arranged on the sides of both edge main grids 12 close to the edge of the substrate 11, so that the operator or the automatic visual system can directly determine the polarities of the two edge main grids 12 through the two mark points 13.

[0105] When the number of the main grids 12 is even, the polarities of the edge main grid 12 at the head end and the edge main grid 12 at the tail end are opposite along the first direction x, and therefore the marking points 13 can be arranged on one side of the edge main grid 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative), so that the operator or the automatic visual system can directly determine the polarity of the other edge main grid 12 as negative (or positive) through the marking points 13 and the number of the main grids 12, thereby reducing the number of the marking points 13 and improving the judgment efficiency and reducing the production cost.

[0106] In a specific embodiment, the first main grid 121 and the second main grid 122 are alternately arranged and spaced along the first direction x, so that the operator or the automatic visual system can also determine the polarity of the adjacent main grid 12 through the size of the marking point 13 coverage area.

[0107] When the number of the main grids 12 is odd, the polarities of the edge main grid 12 at the head end and the edge main grid 12 at the tail end are the same along the first direction x, and therefore the marking points 13 with the same coverage area can be arranged on one side of the two edge main grids 12 close to the edge of the substrate 11, so that the operator or the automatic visual system can directly determine the polarity of the two edge main grids 12 as positive (or negative) through the coverage area of the two marking points 13.

[0108] When the number of the main grids 12 is even, the polarities of the edge main grid 12 at the head end and the edge main grid 12 at the tail end are opposite along the first direction x, and therefore the marking points 13 with a larger coverage area can be arranged on one side of one edge main grid 12 close to the edge of the substrate 11 to mark the polarity of the edge main grid 12 as positive (or negative), and the marking points 13 with a smaller coverage area can be arranged on one 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 automatic visual system can directly determine the polarity of the two edge main grids 12 through the coverage area of the two marking points 13.

[0109] The embodiment of the present application also provides a back contact stacked cell, which comprises a back contact bottom cell and a perovskite top cell, the perovskite top cell is electrically connected with the front surface of the back contact bottom cell, and the back contact bottom cell is the back contact cell 1 described in any one of the above.

[0110] In the embodiments of the present application, when the perovskite top cell and the back contact bottom cell are electrically connected on the front surface to form a back contact stacked cell, the solar spectrum can be used in different wave bands to improve the overall photoelectric conversion efficiency, that is, the perovskite top cell can absorb high-energy short-wavelength photons with a wide bandgap to reduce light loss and improve open-circuit voltage, and the back contact bottom cell can absorb low-energy long-wavelength photons with a narrow bandgap to reduce light-heat loss and improve current density, so that the photoelectric conversion efficiency of the back contact stacked cell can be improved through the synergistic effect of the perovskite top cell and the back contact bottom cell.

[0111] Meanwhile, the back contact stacked cell further comprises an interconnection layer located between the perovskite top cell and the back contact bottom cell in the thickness direction of the back contact stacked cell, which serves to connect and transmit current, facilitates current matching between the two, and can reduce series resistance and improve fill factor to optimize charge transmission efficiency.

[0112] The embodiments of the present application also provide a photovoltaic module comprising the back contact cell 1 of any one of the above or the back contact stacked cell of the above.

[0113] In the embodiments of the present application, the photovoltaic module comprises a first cover plate, a first adhesive film, a cell piece layer, a second adhesive film and a second cover plate stacked in the thickness direction thereof, and the cell piece layer comprises a plurality of cell strings, each of which can comprise a plurality of back contact cells 1 or a plurality of back contact stacked cells. By such a design, the photovoltaic module using the back contact cell 1 or the back contact stacked cell can maximize the use of incident light to improve the photoelectric conversion efficiency, and a wider and thicker metal electrode can be used on the back surface of the cell piece layer, and by optimizing the electrode layout and interconnection mode, the series resistance can be reduced and the fill factor can be improved, thereby facilitating the improvement of the electrical performance of the photovoltaic module and the improvement of the safety and reliability of the photovoltaic module during operation.

[0114] The back contact cell 1 can be electrically connected in the form of a whole piece or a plurality of split pieces to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or parallel to form a cell piece layer. The back contact cell 1 includes but is not limited to an IBC cell (Interdigitated Back Contact Battery), an HBC cell (Heterojunction Back Contact Battery), a TBC cell (TOPCon Back Contact Battery) or an HPBC cell (Hybrid Passivated Back Contact Battery).

[0115] Meanwhile, the first cover plate is located at the light-receiving side of the cell layer, so that it can be super-white photovoltaic embossed glass or super-white processed float glass, etc., so as to have good light transmittance, so as to guarantee the photoelectric conversion efficiency of the photovoltaic module; the second cover plate is located at the back side of the cell layer, so that it can be calendaring glass or super-white calendaring glass, etc., so as to have good weather resistance, so as to guarantee the impact strength of the photovoltaic module.

[0116] In addition, the first adhesive film is located between the first cover plate and the light-receiving side of the cell layer, and the second adhesive film is located between the second cover plate and the back side of the cell layer, so as to fixedly connect the cover plate and the cell layer, and isolate the cell layer from the external environment, so as to reduce the possibility of mechanical damage or chemical corrosion of the cell layer, guarantee the reliability of the photovoltaic module during operation, thereby being conducive to prolonging the service life. At least one of the first adhesive film and the second adhesive film can be ethylene-vinyl acetate copolymer adhesive film (EVA adhesive film), polyolefin elastomer adhesive film (POE adhesive film), polyvinyl butyral adhesive film (PVB adhesive film), or polyethylene terephthalate (PET) adhesive film, etc. At least one of the first adhesive film and the second adhesive film can also be EP adhesive film (co-extrusion adhesive film composed of EVA adhesive film and POE adhesive film arranged in layers), EPE adhesive film (co-extrusion adhesive film composed of EVA adhesive film, POE adhesive film and EVA adhesive film arranged in layers), or PVP adhesive film (co-extrusion adhesive film composed of POE adhesive film, EVA adhesive film and POE adhesive film arranged in layers), etc.

[0117] The above describes the structure, features and effects of the application in detail according to the embodiments shown in the drawings. The above description is only the preferred embodiments of the application, but the application is not limited by the drawings. Any changes or modifications made in accordance with the concept of the application, or equivalent embodiments with equivalent changes, are still within the scope of the application.

Claims

1. A back contact cell, characterized in that, The back contact battery includes: Base; The main gate is disposed on the back side of the substrate; Marker points are disposed on the back side of the substrate and located on at least one side of the main gate near the edge of the substrate; The main grid includes a first main grid and a second main grid arranged alternately along a first direction x. Along the first direction x, the marking point is located on the side of the outermost main grid near the edge of the substrate, and is used to mark the polarity of the main grid adjacent to the marking point. The back contact battery also includes a fine grid, which includes a first fine grid and a second fine grid arranged alternately 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 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. 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.

2. The back contact cell of claim 1, wherein, Along the second direction y, a marking area is formed between the two outermost first insulating adhesives, and the marking point covers at least two adjacent first insulating adhesives within the marking area; or, a marking area is formed between the two outermost second insulating adhesives, and the marking point covers at least two adjacent second insulating adhesives within the marking area.

3. The back contact cell of claim 1, wherein, Along the second direction y, the length of the marked point is a, the width of the insulating adhesive is d, and the ratio of a to d satisfies 3≤a / d≤15.

4. The back contact cell of claim 1, wherein, The marking points are made of the same material as the first insulating adhesive and the second insulating adhesive.

5. The back contact cell according to any of claims 1-4, wherein, Along the first direction x, the distance between the marker point and the edge of the base is L1, and L1 satisfies 0.2mm≤L1≤3mm.

6. The back contact battery according to any one of claims 1-4, characterized in that, Along the second direction y, the length of the marker point is a, and a satisfies 0.8mm≤a≤3mm; along the first direction x, the width of the marker point is b, and b satisfies 0.2mm≤b≤1mm.

7. The back contact battery according to any one of claims 1-4, characterized in that, The shape of the marker point is one of rectangle, triangle, and ellipse.

8. A back-contact stacked battery, characterized in that, The back-contact stacked battery includes a back-contact bottom battery and a perovskite top battery, wherein the perovskite top battery is electrically connected to the front side of the back-contact bottom battery, and the back-contact bottom battery is the back-contact battery according to any one of claims 1-7.

9. A photovoltaic module, characterized in that, The photovoltaic module includes the back-contact battery as described in any one of claims 1-7 or the back-contact tandem battery as described in claim 8.

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