Photovoltaic module and photovoltaic system

Abstract

The invention provides a photovoltaic module and a photovoltaic system, and relates to the technical field of photovoltaics. The photovoltaic module comprises a conductive backboard and a back contact battery piece arranged on the conductive backboard. The back contact battery piece comprises a plurality of current collection grid lines and a plurality of current collection grid lines. The conductive back plate comprises a conductive layer and an insulating layer located between the conductive layer and the back contact battery piece; a through hole is formed in the position, corresponding to the bus grid line, in the insulating layer, the through hole is filled with a bonding material, and the bus grid line is electrically connected with the conducting layer through the bonding material in the through hole; in a back contact battery piece area, the ratio of the total number of the through holes in the area, corresponding to one column of bus grid lines, in the insulating layer to the total column number of the bus grid lines in one back contact battery piece is 0.17-3. The photovoltaic module is low in hidden crack risk, high in current transmission efficiency, good in insulating performance of the insulating layer, good in reliability and simple in technological process.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a photovoltaic component and a photovoltaic system. Background Art

[0002] Back-contact cells can make full use of sunlight due to their structure without grid lines on the light-facing side, making them more efficient. However, a single back-contact cell has poor mechanical strength, is easily affected by the environment, and has low output voltage, current, and power. Therefore, it is usually necessary to package multiple back-contact cells into a photovoltaic module.

[0003] In existing photovoltaic modules, welding strips are welded to the busbars of the back contact cells to conduct current.

[0004] However, the thermal effects of the welding process can introduce risks of hidden cracks in the back-contact cells, affecting the quality and reliability of photovoltaic modules. Summary of the invention

[0005] The present invention provides a photovoltaic module and a photovoltaic system, aiming to solve the problem of hidden crack risk introduced by welding in the existing photovoltaic modules.

[0006] A first aspect of the present invention provides a photovoltaic module, comprising: a conductive back sheet, and a back contact cell sheet disposed on the conductive back sheet; The back contact cell comprises: a plurality of collector grid lines and a plurality of bus grid lines; the collector grid lines extend along a first direction, and the collector grid lines with different polarities are alternately and spaced along a second direction; the first direction is different from the second direction; the bus grid lines extend along the second direction, and the bus grid lines with different polarities are alternately and spaced along the first direction; the collector grid lines and the bus grid lines with the same polarity are electrically connected; The conductive backplane comprises: a conductive layer, and an insulating layer located between the conductive layer and the back contact cell; a through hole is opened in the insulating layer at a position corresponding to the busbar line, the through hole is filled with a bonding material, and the busbar line is electrically connected to the conductive layer through the bonding material in the through hole; In one back-contact cell region, the ratio of the total number of through holes in a region of the insulating layer corresponding to a column of busbar lines to the total number of columns of busbar lines in one back-contact cell is 0.17 to 3.

[0007] First, this application does not use the method of welding with welding strips, but uses a conductive backplane for current conduction. Since welding is basically unnecessary, there is basically no risk of introducing hidden cracks to the back contact cell, and the risk of hidden cracks in the photovoltaic module is low. The conductive backplane includes a conductive layer, and an insulating layer located between the conductive layer and the back contact cell. In the insulating layer, a through hole is opened at a position corresponding to the busbar line. The through hole of the insulating layer is filled with a bonding material. The busbar line is electrically connected to the conductive layer through the bonding material in the through hole to conduct current, and the insulating layer avoids the risk of short circuit.Secondly, in the present application, the electrical connection between a column of busbar lines and the conductive layer is achieved by means of the bonding material in the through-holes in the area corresponding to the column of busbar lines. Therefore, in a back-contact cell area, the total number of through-holes in the insulating layer in the area corresponding to a column of busbar lines, and the total number of columns of busbar lines in a back-contact cell, these two factors are closely related to the current conduction quality. Specifically, as the total number of columns of busbar lines in a back-contact cell increases, it is beneficial to increase the current collection capacity of the back-contact cell and reduce the resistance loss, thereby improving the power of the photovoltaic module. However, when the total number of columns increases to a certain extent, the effect of improving the current collection capacity and reducing the resistance loss will increase. The beneficial boundary effect is reduced, that is, too many busbar lines will lead to an increase in the amount of materials used, increase the amount of materials such as silver paste, and thus increase the material cost; secondly, too many busbar lines will also increase the difficulty of aligning the busbar lines and the conductive backplane, and increase the manufacturing precision requirements for the busbar lines and the conductive backplane, which increases the manufacturing difficulty; in addition, too many busbar lines will also cause an increase in stress on the back of the battery, especially at the junction of the busbar lines and the collector grid lines, which will form local stress and cause the phenomenon of broken grids, which will have a negative impact on the performance of photovoltaic modules; too many busbar lines will reduce the effective area of ​​the back contact cell surface for absorbing light, thereby reducing the photoelectric conversion efficiency. Therefore, choosing The appropriate total number of columns needs to find a balance between the current collection capacity, resistance loss, illumination area utilization, and cost and reliability of the back contact cell, so as to achieve the best performance and cost-effectiveness balance; at the same time, the more the total number of through holes in the area corresponding to a column of busbar lines in the insulating layer, the more current transmission channels there are for current to be transmitted from the back contact cell to the conductive backplane, the better the uniformity of current transmission, and the higher the current transmission efficiency. However, too many through holes will reduce the bonding area between the insulating layer and the back contact cell, and will also weaken the overall strength of the insulating layer, causing its plastic deformation. Plastic deformation may also cause the insulation of the insulating layer to decrease, causing the risk of short circuit. At the same time, it will also increase the difficulty of the process. Therefore, choosing an appropriate total number requires finding a balance between the current transmission efficiency of the back contact cell, the bonding strength and insulation performance between the insulating layer and the back contact cell, and the process. More specifically, if the ratio of the total number of through holes in the area corresponding to a column of bus bars in the insulating layer to the total number of bus bars in a back contact cell is too large, then the number of bus bars relative to the number of through holes will cause uneven current collection on the surface of the back contact cell and reduce the current collection capacity. Or, if the number of through holes is too large relative to the total number of bus bars, the overall strength of the insulating layer will be weakened, and the insulation and bonding properties will be reduced, resulting in reliability problems.If the ratio of the total number of through holes in the area corresponding to a column of busbar lines in the insulating layer to the total number of columns of busbar lines in a back-contact cell is too small, the number of busbar lines is relatively large, resulting in a reduction in the area of ​​the back-contact cell surface that absorbs light, which will reduce the power generation efficiency of the back-contact cell and increase the manufacturing cost and complexity; or if the number of through holes is too small relative to the number of busbar lines, the current transmission channel is insufficient, which will affect the transmission efficiency of the current from the back-contact cell to the conductive backplane. Therefore, in the present application, in a back-contact cell area, the ratio of the total number of through holes in the area corresponding to a column of busbar lines in the insulating layer to the total number of columns of busbar lines in a back-contact cell is 0. .17 to 3, this ratio range is a suitable ratio range selected when the current transmission efficiency of the back contact cell, the bonding strength and insulation performance of the insulating layer and the back contact cell, and the process are relatively balanced. Therefore, in this photovoltaic module, the current collection ability of the back contact cell is strong and the resistance loss is low, the utilization rate of the illuminated area is high, the power generation efficiency of the back contact cell is high, the manufacturing cost is low, and the preparation process is relatively simple. In addition, in this photovoltaic module, not only the current collection uniformity is good and the current transmission efficiency is high, but also the bonding strength between the insulating layer and the back contact cell is high, the insulation performance of the insulating layer is good, and the reliability of the photovoltaic module is better. At the same time, the process of the insulating layer is simple and the yield is high.

[0008] Optionally, the total number is 5 to 25, the number of current transmission channels for transmitting current from the back contact battery cell to the conductive backplane is appropriate, the current transmission uniformity is better, the current transmission efficiency is higher, and the number of through holes is not too large, which will not reduce the bonding area between the insulating layer and the back contact battery cell. The overall strength of the insulating layer is higher and the insulation is better, the short circuit risk is lower, and the process is simple. In summary, the total number is within the above range, which finds a good balance between the current transmission efficiency of the back contact battery cell, the bonding strength and insulation performance of the insulating layer and the back contact battery cell, and the process.

[0009] Optionally, in the first direction, the through hole in the insulating layer extends at most to a position corresponding to a center line of an adjacent bus grid line. In the first direction, adjacent bus grid lines are bus grid lines with different polarities. The through hole in the insulating layer extends at most to a position corresponding to a center line of two adjacent bus grid lines. While being compatible with alignment errors, grid lines of two polarities are generally not exposed at the same time in the through hole, thereby reducing the risk of short circuit.

[0010] Optionally, one of the through holes only covers the collector grid lines and bus grid lines of the same polarity, and the collector grid lines and bus grid lines of the same polarity are electrically connected to the conductive layer through the bonding material. The collector grid lines and bus grid lines of the other polarity around the through hole are shielded by the insulating layer to avoid short circuits, thereby ensuring good electrical insulation. Therefore, there is no need to set insulating parts on the collector grid lines and bus grid lines of the other polarity around the through hole, and the process is simple with a low risk of short circuits.

[0011] Optionally, the distance between the through hole and the collector grid line of another polarity adjacent to the outside thereof is greater than or equal to 0.1 mm. Under the condition of compatible process errors, there is no need to set an insulating member on the collector grid line and bus grid line of another polarity, and the risk of short circuit is avoided.

[0012] Optionally, the back contact cell further comprises: a plurality of electrical connection parts electrically connected to the busbar lines; the electrical connection parts are located in the through holes.

[0013] Optionally, the distance between the edge of the through hole and the edge of the electrical connection part in the through hole is greater than or equal to 0.2 mm, so that the bonding material is located in the through hole as much as possible, the contact area between the bonding material and the conductive layer is as large as possible, and the power loss is small.

[0014] Optionally, in the first direction, the ratio of the size of the through hole to the size of the electrical connection part is 1.1 to 3; and / or, in the second direction, the ratio of the size of the through hole to the size of the electrical connection part is 1.1 to 3. In the first direction and / or the second direction, the through hole has sufficient redundant space to accommodate the position error of the arrangement of slices, which can ensure that the bonding material can pass through the through hole as completely as possible, the interconnection quality can be guaranteed, and the short-circuit efficiency is also low. The bonding material will basically not be offset, and the through hole will not be too large to avoid the risk of short circuit.

[0015] Optionally, the insulating layer includes: a first surface close to the back contact battery cell; the distance between the orthographic projection of the geometric center of the through hole on the first surface and the orthographic projection of the geometric center of the electrical connection part in the through hole on the first surface is less than or equal to 1 mm, so that the bonding material is located in the through hole as much as possible, the contact area between the bonding material and the conductive layer is as large as possible, the power loss is small, the through hole has enough redundant space to accommodate the position error of the chip arrangement, and can ensure that the bonding material can pass through the through hole as completely as possible, the interconnection quality can be guaranteed, and the short-circuit efficiency is also low, the bonding material will basically not shift, and the short-circuit risk is low.

[0016] Optionally, the insulating layer includes: a first surface close to the back contact battery cell; the orthographic projection of the electrical connection portion on the first surface is a first orthographic projection, and the orthographic projection of the through hole on the first surface is a second orthographic projection; the area of ​​the second orthographic projection is greater than or equal to 1.3 in ratio to the area of ​​the first orthographic projection, and the through hole has sufficient redundant space to accommodate the position error of the arrangement of the cells, so as to ensure that the bonding material can pass through the through hole as completely as possible, the interconnection quality can be guaranteed, the effective transmission of current can be guaranteed, and the short-circuit efficiency is also low, the bonding material will basically not shift, and the short-circuit risk is low.

[0017] Optionally, the bonding material is arranged on the second surface of the electrical connection part close to the insulating layer; the orthographic projection of the bonding material on the second surface and its extended surface is a third orthographic projection, and the third orthographic projection is located within the second surface. The bonding material does not exceed the second surface of the electrical connection part, thereby minimizing the risk of short circuit caused by the offset of the bonding material.

[0018] Optionally, the bonding material is arranged on the second surface of the electrical connection portion close to the insulating layer; the orthographic projection of the bonding material on the second surface and its extended surface is a third orthographic projection, the area of ​​the third orthographic projection is less than or equal to the area of ​​the second surface, and the area of ​​the orthographic projection of the bonding material is slightly smaller, thereby reducing the risk of short circuit caused by offset of the bonding material.

[0019] Optionally, the volume of the bonding material accounts for 9.8% to 80% of the volume of the through hole. The content of the bonding material is not too small, the electrical connection between the bus bar and the conductive layer is more reliable, which is conducive to the effective transmission of current. The content of the bonding material is not too much, avoiding the risk of short circuit caused by overflow of the bonding material.

[0020] A second aspect of the present invention provides a photovoltaic system, comprising: a plurality of any of the aforementioned photovoltaic modules.

[0021] The above-mentioned photovoltaic modules and photovoltaic systems have the same or similar beneficial effects, which will not be described again here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0023] Figure 1 A schematic front cross-sectional view of a photovoltaic module in an embodiment of the present invention is shown; Figure 2 A partial structural schematic diagram of a back contact cell in an embodiment of the present invention is shown; Figure 3 A schematic structural diagram of an insulating layer in an embodiment of the present invention is shown; Figure 4 A schematic diagram of the structure of a back contact battery cell and an insulating layer in an embodiment of the present invention is shown; Figure 5 A schematic structural diagram of a conductive layer in an embodiment of the present invention is shown; Figure 6 A schematic diagram of the structure of the conductive layer and the insulating layer in the embodiment of the present invention is shown; Figure 7 A partial structural schematic diagram of another back contact cell in an embodiment of the present invention is shown; Figure 8 A schematic diagram showing the coordination of the insulating layer, the back contact cell sheet and the conductive layer in an embodiment of the present invention is shown; Fig. 9 A partial enlarged structural schematic diagram of a back contact battery cell and an insulating layer in an embodiment of the present invention is shown; Fig.10 A schematic diagram of a partially enlarged structure of the cooperation between a conductive layer and an insulating layer in an embodiment of the present invention is shown.

[0024] Description of the accompanying drawings: 1-conductive backplane, 11-insulating layer, 111-through hole, 112-bonding material, 12-conductive layer, 13-rear packaging film, 14-backplane, 2-back contact cell sheet, 3-front packaging film, 4-glass, 21-collecting grid line, 22-bus grid line, 23-electrical connection part. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a photovoltaic module, referring to Figure 1 The photovoltaic module comprises: a conductive back sheet 1, and a back contact cell sheet 2 arranged on the conductive back sheet 1. Figure 1 The photovoltaic module may also include: a front packaging film 3 and a glass 4 which are sequentially located on the side of the back contact cell sheet 2 away from the conductive back sheet 1 .

[0027] Reference Figure 2, the back contact cell 2 includes: a plurality of collector grid lines 21 and a plurality of bus grid lines 22. The plurality of collector grid lines 21 include: collector grid lines 21 with different polarities, where the collector grid lines 21 with different polarities refer to N-type collector grid lines and P-type collector grid lines. The collector grid lines extend along the first direction L1, and the collector grid lines 21 with different polarities are alternately and spaced along the second direction L2. The spacing here can avoid short circuits. The alternation here means that in the second direction L2, an N-type collector grid line is followed by a P-type collector grid line and then by an N-type collector grid line. The first direction L1 is different from the second direction L2, and the angle between the two is not limited. For example, they can be perpendicular or nearly perpendicular to each other. The plurality of bus grid lines 22 include: bus grid lines 22 of different polarities, where the bus grid lines 22 of different polarities refer to N-type bus grid lines and P-type bus grid lines, where the N-type bus grid lines and the N-type collector grid lines have the same polarity, and the P-type bus grid lines and the P-type collector grid lines have the same polarity. The bus grid lines extend along the second direction L2. The bus grid lines 22 of different polarities are alternately and spaced along the first direction L1, where the spacing can avoid short circuits, where the alternation means that in the first direction L1, one or a row of N-type bus grid lines are followed by one or a row of P-type bus grid lines, followed by one or a row of N-type bus grid lines. The collector grid lines and bus grid lines of the same polarity are electrically connected, and the two can be electrically connected by intersecting. The back contact cell here can be a whole cell, or can be a half cell, a three-cell cell, a four-cell cell, etc., without specific limitation.

[0028] Reference Figure 1 The conductive backplane 1 includes: a conductive layer 12, and an insulating layer 11 between the conductive layer 12 and the back contact cell 2. The conductive layer 12 is formed of a conductive material, such as a metal foil, etc., which is not specifically limited. The insulating layer 11 can be a single-layer structure or a multi-layer structure, for example, the insulating layer 11 can be a PO (polypropylene oxide)\PE (polyethylene)\PF (phenolic resin)\PET (polyethylene terephthalate) laminated structure.

[0029] Reference Figure 1 and Figure 3 In the insulating layer 11, a through hole 111 is provided at a position corresponding to the busbar line. Figure 4 , through hole 111 can expose part of the busbar line, refer to Figure 5 The conductive layer 12 is a finger-shaped alternating distribution structure, which can ensure the accumulation relationship during the current transmission process and improve the current collection efficiency. The conductive layer 12 is provided with isolation to avoid short circuit. Figure 6 , the through hole 111 can allow part of the conductive layer to be exposed. Figure 1The through hole 111 is filled with a bonding material 112, and the bonding material 112 can be arranged on a partially exposed busbar line, and the bonding material 112 extends into the through hole 111, referring to Figure 1 The partially exposed busbar lines are electrically connected to the partially exposed conductive layer 12 through the bonding material 112 in the through hole 111 to conduct the current. Other areas of the back contact cell 2 are in contact with the insulating layer 11 to avoid short circuits and power losses. At the same time, some areas of the insulating layer 11 that are close to the back contact cell in the thickness direction will be bonded to the corresponding positions of the back contact cell. In this application, the welding method of welding strips is not used, but a conductive backplane 1 is selected for current conduction. Because this application does not require welding, there is basically no risk of introducing hidden cracks to the back contact cell and photovoltaic module. Refer to Figure 1 The conductive backplane 1 may further include: a rear encapsulation film 13 and a backplane 14 sequentially stacked on the side of the conductive layer 12 away from the back contact cell 2. The bonding material 112 may be a conductive adhesive, solder paste, etc., or the bonding material 112 may contain metal components such as silver, copper, lead, bismuth, zinc, nickel, etc., and the specific components of the bonding material 112 are not specifically limited.

[0030] Reference Figure 4 and Figure 8 , in a back contact cell region, the total number of through holes 111 in the insulating layer 11 corresponding to a column of busbars is the number of through holes 111 in the insulating layer 11 at least partially collinear along the second direction L2. A column of busbars refers to at least one busbar that is at least partially collinear in the second direction L2. If the busbars are continuously arranged in the second direction L2, then one busbar is a column of busbars. If the busbars are discontinuously arranged in the second direction, then a plurality of busbars that are at least partially collinear in the second direction L2 is a column of busbars. For example, Figure 4 In the embodiment, the busbar lines 22 are arranged continuously in the second direction L2, and one busbar line is a column of busbar lines. Figure 4 The total number of busbar lines in the back contact cell 2 shown is 10. Figure 4 and Figure 8 In a back contact cell region, the ratio of the total number of through holes 111 in the insulating layer 11 corresponding to a column of busbar lines to the total number of columns of busbar lines in a back contact cell 2 is 0.17 to 3. The electrical connection between a column of busbar lines and the conductive layer 12 is achieved by means of the bonding material 112 in the through holes 111 in the region corresponding to the column of busbar lines, so the total number of through holes 111 in the insulating layer 12 corresponding to a column of busbar lines and the total number of columns of busbar lines in a back contact cell 2 are both closely related to the current conduction quality.

[0031] Specifically, as the total number of busbar lines in a back-contact cell 2 increases, it is beneficial to increase the current collection capacity of the back-contact cell 2 and reduce resistance loss, thereby increasing the power of the photovoltaic module. However, when the total number of columns increases to a certain extent, the boundary effect of improving the current collection capacity and reducing resistance loss gain decreases, that is, too many busbar lines will lead to an increase in the amount of materials used, increase the amount of materials such as silver paste, and then increase the material cost; secondly, too many busbar lines will also increase the difficulty of aligning the busbar lines and the conductive backplane, increase the manufacturing precision requirements for the busbar lines and the conductive backplane, and increase the manufacturing difficulty; In addition, too many busbar lines will also increase the stress on the back of the battery, especially at the intersection of the busbar lines and the collector lines, which will form local stress and cause the phenomenon of broken grid, which will have a negative impact on the performance of the photovoltaic module; too many busbar lines will reduce the effective area of ​​the back contact cell 2 surface for absorbing light, thereby reducing the photoelectric conversion efficiency. Therefore, choosing a suitable total number of columns requires finding a balance between the current collection capacity of the back contact cell 2, resistance loss, light area utilization, and cost and reliability, so as to achieve the best performance and cost-effectiveness balance; at the same time, the insulation layer 11 and the The more the total number of through holes 111 in the area corresponding to a column of busbar lines, the more current transmission channels there are for current to be transmitted from the back contact battery cell 2 to the conductive back plate 1, the better the uniformity of current transmission, and the higher the current transmission efficiency. However, too many through holes 111 will reduce the bonding area between the insulating layer 11 and the back contact battery cell 2, and will also weaken the overall strength of the insulating layer 11, causing its plastic deformation. Plastic deformation may also cause the insulation of the insulating layer 11 to decrease, causing the risk of short circuit, and also increase the difficulty of the process. Therefore, choosing an appropriate total number requires a certain amount of through holes 111 in the current transmission of the back contact battery cell 2. A balance is sought between efficiency, the bonding strength and insulation performance of the insulating layer 11 and the back contact cell 2, and the process flow; more specifically, if the ratio of the total number of through holes 111 in the area corresponding to a column of bus bars in the insulating layer 11 to the total number of columns of bus bars in a back contact cell 2 is too large, the number of bus bars is relatively small relative to the number of through holes 111, which will cause uneven current collection on the surface of the back contact cell 2 and reduce the current collection capacity; or if the number of through holes 111 is too large relative to the number of bus bars, the overall strength of the insulating layer 11 will be weakened, the insulation performance and bonding performance will be reduced, and reliability problems will be caused.If the ratio of the total number of through holes 111 in the insulating layer 11 corresponding to a column of busbar lines to the total number of busbar lines in a back-contact cell 2 is too small, the number of busbar lines is relatively large relative to the through holes 111, resulting in a reduction in the area of ​​the back-contact cell 2 that absorbs light, which will reduce the power generation efficiency of the back-contact cell 2 and increase the manufacturing cost and complexity; or if the number of through holes 111 is too small relative to the number of busbar lines, the current transmission channel is insufficient, which will affect the transmission efficiency of the current from the back-contact cell 2 to the conductive backplane 1. Therefore, in the present application, in a back-contact cell area, the ratio of the total number of through holes 111 in the insulating layer 11 corresponding to a column of busbar lines to the total number of busbar lines in a back-contact cell 2 is The ratio is 0.17 to 3, which is a suitable ratio range selected under the condition that the current transmission efficiency of the back contact cell 2, the bonding strength and insulation performance of the insulating layer 11 and the back contact cell 2, and the process are relatively balanced. Therefore, in the photovoltaic module, the current collection ability of the back contact cell 2 is strong and the resistance loss is low, the utilization rate of the illuminated area is high, the power generation efficiency of the back contact cell 2 is high, the manufacturing cost is low, and the preparation process is relatively simple. In addition, the photovoltaic module not only has good current collection uniformity and high current transmission efficiency, but also has high bonding strength between the insulating layer 11 and the back contact cell 2, good insulation performance of the insulating layer 11, and better reliability of the photovoltaic module. At the same time, the process of the insulating layer 11 is simple, the yield is high, and it is easy to mass produce.

[0032] For example, Figure 4 and Figure 8 In the example, the total number of through holes 111 in the region corresponding to a column of busbar lines in the insulating layer 11 is 5, the total number of columns of busbar lines in a back contact cell 2 is 10, and the ratio of the total number to the total number of columns is: 5 / 10=0.5. For another example, in a photovoltaic module, the ratio of the total number to the total number of columns can be 0.17, 0.25, 0.39, 0.42, 0.45, 0.5, 0.56, 1.11, 2.78, 3, etc.

[0033] For another example, in a back contact cell region, the total number of through holes 111 in the region of the insulating layer 11 corresponding to a column of bus bars is 6, and the total number of columns of bus bars in a back contact cell 2 can be 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, and the ratio of the total number to the total number of columns is 0.38, 0.33, 0.3, 0.27, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17; for another example, in a back contact cell region, the total number of through holes 111 in the region of the insulating layer 11 corresponding to a column of bus bars can be 7, and the total number of columns of a back contact cell 2 can be 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, and the ratio of the total number to the total number of columns is 0.38, 0.33, 0.3, 0.27, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17. 2 can be 16, 18, 20, 22, 24, 26, 28, 30, and the ratio between the two can be 0.438, 0.389, 0.35, 0.318, 0.292, 0.269, 0.25, 0.233; for another example, in a back contact cell area, the total number of through holes 111 in the area corresponding to a column of bus bars in the insulating layer 11 is 8, and the total number of bus bars in a back contact cell 2 can be 14, 16, 18, 20, 22, 24, 26, 28, 30, and the ratio between the total number and the total number of columns is 0.57, 0.5, 0.44, 0.4, 0.36, 0.33, 0.31, 0.29, 0.27; for another example, in a back contact cell region, the total number of through holes 111 in the region of the insulating layer 11 corresponding to a column of bus bars may be 9, and the total number of columns of bus bars in a back contact cell 2 may be 16, 18, 20, 22, 24, 26, 28, 30, and the ratio between the two may be 0.56, 0.5, 0.45, 0.429, 0.375, 0.35, 0.32, 0.3; for another example, in a back contact cell region, the total number of through holes 111 in the region of the insulating layer 11 corresponding to a column of bus bars is 10, and the total number of columns of bus bars in a back contact cell 2 is 16, 18, 20, 22, 24, 26, 28, 30, and the ratio between the two may be 0.56, 0.5, 0.45, 0.429, 0.375, 0.35, 0.32, 0.3. The number of columns can be 12, 14, 16, 18, 20, 22, 24, 26, 28, and the ratio of the total number to the total number of columns is 0.83, 0.71, 0.63, 0.56, 0.5, 0.45, 0.42, 0.38, 0.36; for another example, in a back contact cell region, the total number of through holes 111 in the region corresponding to a column of busbar lines in the insulating layer 11 can be 11, and the total number of columns of busbar lines in a back contact cell 2 can be 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and the ratio of the two can be 0.92, 0.79, 0.69, 0.611, 0.55, 0.5, 0.46, 0.42, 0.39, 0.37; for another example, in a back contact cell region, the total number of through holes 111 in the insulating layer 11 corresponding to a column of bus bars can be 12, and the total number of columns of bus bars in a back contact cell 2 is 10, 12, 14, 16, 18, 20, 22, 24, 26, and the ratio of the total number to the total number of columns is 1.2, 1, 0.86, 0.75, 0.67, 0.6, 0.54, 0.5, 0.46; for another example, in a back contact cell region, the total number of through holes 111 in the insulating layer 11 corresponding to a column of bus bars can be 14, and the total number of columns of bus bars in a back contact cell 2 is 8 , 10, 12, 14, 16, 18, 20, 22, 24, and the ratio of the total number to the total number of columns is 1.75, 1.4, 1.17, 1, 0.88, 0.78, 0.7, 0.64, 0.58, 0.54; for another example, in a back contact cell area, the total number of through holes 111 in the area corresponding to a column of busbar lines in the insulating layer 11 can be 18, and the total number of busbar lines in a back contact cell 2 is 6, 8, 10, 12, 14, 16, 18, 20, 22, and the ratio of the total number to the total number of columns is 3, 2.25, 1.8, 1.5, 1.29, 1.13, 1, 0.9, 0.82. .

[0034] For another example, in a back contact cell area, the total number of columns of bus bars in a back contact cell 2 is 16, and the total number of through holes 111 in the area corresponding to a column of bus bars in the insulating layer 11 can be 7, 8, 9, 10, 11, 12, and the ratio of the total number of through holes 111 to the total number of columns of bus bars is 0.38, 0.44, 0.5, 0.56, 0.63, 0.69, 0.75; for another example, in a back contact cell area, the total number of columns of bus bars in a back contact cell 2 is 18, and the total number of through holes 111 in the area corresponding to a column of bus bars in the insulating layer 11 can be 7, 8, 9, 10, 11, 12, and the ratio of the total number of through holes 111 to the total number of columns of bus bars is 0.39, 0.44, 0.5, 0.56, 0.61, 0.67; other situations are analogous and will not be described here.

[0035] Specifically, in a photovoltaic module, the total number of busbar lines in a back-contact cell 2 has a certain lower limit of power transmission loss. The power transmission loss curve is similar to a U-shaped curve with the opening facing upward. When the power transmission loss is minimized, the total number of busbar lines in a back-contact cell 2 is between 12 and 30. At the same time, an increase in the total number of busbar lines in a back-contact cell 2 will increase the total number of openings, resulting in a decrease in the opening capacity, and equipment upgrades may be required. In addition, the number of busbar lines in a back-contact cell 2 is When the total number of columns increases to a certain extent, the efficiency of the back-contact cell gradually tends to be flat, and further increase will lead to an increase in the wet weight of the electrode slurry. In summary, the total number of columns of busbar lines in a back-contact cell 2 can be 16, 18, 20, 22, 24, 26, 28, which is the result of a balance of multiple factors such as power transmission loss, opening capacity, efficiency, and wet weight of the electrode slurry. Here, the total number of columns is an even number (that is, the total number of columns of N-type busbar lines and P-type busbar lines is equal), which is also beneficial to process technology and photovoltaic module design. In addition, in a back-contact cell area, an increase in the total number of through holes 111 in the insulating layer 11 corresponding to a column of bus bars is beneficial to power improvement, but each increase in the number of openings will reduce production capacity and require more equipment investment; and the more openings there are, the more electrical connection positions there are, and process risks such as electrical connection reliability also increase accordingly; at the same time, in a back-contact cell containing electrical connections, the more openings there are, the more electrical connections there are, and when the number of electrical connections increases to a certain extent, the efficiency improvement of the back-contact cell tends to be flat, but more electrical connections will bring a larger wet weight of the electrode slurry. Therefore, in a back-contact cell area, the total number of through holes 111 in the insulating layer 11 corresponding to a column of bus bars can be 7, 8, 9, 10, 11, or 12, which is the result of a balance between multiple factors such as production capacity, process risk, efficiency, and wet weight of electrode slurry.

[0036] It should be noted that whether the total number of through holes 111 in the region corresponding to each column of busbar lines in the portion corresponding to one back-contact cell in the insulating layer 11 is equal is not specifically limited. Whether the total number of through holes 111 in the region corresponding to a column of busbar lines of one back-contact cell in the insulating layer 11 is equal to the total number of through holes 111 in the region corresponding to a column of busbar lines of another back-contact cell in the insulating layer 11 is equal is not specifically limited. In the case where the total number of through holes 111 in the region corresponding to each column of busbar lines in the portion corresponding to one back-contact cell in the insulating layer 11 is not equal, the ratio of the total number of through holes 111 in the region corresponding to at least one column of busbar lines in the portion corresponding to one back-contact cell in the insulating layer 11 to the total number of columns of busbar lines in the back-contact cell may be 0.17 to 3.

[0037] It should be noted that the shape of the through hole 111 is not limited in the present application. For example, the through hole 111 may be a circular through hole, a square hole, etc. In the case where the through hole is formed by laser, the circular through hole has certain process advantages for the laser equipment, and can avoid corners like polygons to reduce production capacity and laser power loss. In addition, in the case where the through hole 111 is a circular through hole, the circular through hole can also exist as a positioning mark, thereby reducing the setting of the positioning mark.

[0038] Optionally, the total number of through holes 111 in the area corresponding to a column of busbar lines in the insulating layer 11 can be 5 to 25. When the total number is less than 5, it affects the collection of current. When the total number is greater than 25, the number of through holes is large, which will increase the processing time and difficulty. Moreover, if the through hole area is too large, the hollow area of ​​the insulating layer will increase. At this time, the plasticity of the insulating layer becomes poor and deformation is prone to occur, which will introduce process problems. In view of the above problems, in the present application, the total number is 5 to 25, the number of current transmission channels for transmitting current from the back contact battery cell 2 to the conductive back plate 1 is more appropriate, the uniformity of current transmission is better, the current transmission efficiency is higher, and the number of through holes 111 is not too large, which will not reduce the bonding area between the insulating layer 11 and the back contact battery cell 2. The overall strength of the insulating layer 11 is higher and the insulation is better, the short circuit risk is lower, and the process is simple. In summary, the total number is within the above range, which is a good balance between the current transmission efficiency of the back contact battery cell 2, the bonding strength and insulation performance of the insulating layer 11 and the back contact battery cell 2, and the process.

[0039] For example, the total number of through holes 111 in the region of the insulating layer 11 corresponding to a column of bus bars may be 7 to 12. For another example, the total number of through holes 111 in the region of the insulating layer 11 corresponding to a column of bus bars may be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25.

[0040] Optionally, in the first direction L1, the through hole 111 in the insulating layer 11 extends at most to a position corresponding to a center line of two adjacent bus grid lines, further reducing the risk of short circuit. Specifically, in the first direction L1, two adjacent bus grid lines are bus grid lines with different polarities, and the through hole 111 in the insulating layer 11 extends at most to a position corresponding to a center line of two adjacent bus grid lines. Under the condition of compatible alignment error, gate lines of two polarities are generally not exposed at the same time in the through hole 111, thereby reducing the risk of short circuit.

[0041] Fig. 9 yes Figure 4 Optional, see Fig. 9, a through hole 111 only covers the collector grid line and the bus grid line of the same polarity, where the collector grid line and the bus grid line of the same polarity refer to the N-type collector grid line and the N-type bus grid line, or the P-type collector grid line and the P-type bus grid line, that is, only the collector grid line and the bus grid line of the same polarity are exposed in the through hole 111, and the collector grid line and the bus grid line of the other polarity around the through hole will be blocked by the insulating layer, that is, for a through hole 111, only the collector grid line and the bus grid line of the same polarity will be electrically connected to the conductive layer 12 through the bonding material 112, and the collector grid line and the bus grid line of the other polarity around the through hole 111 are blocked by the insulating layer to avoid short circuit. The through hole 111 is a through hole 111, which ensures good electrical insulation. Therefore, there is no need to set insulating parts on the collector grid lines and bus grid lines of another polarity around the through hole 111. The process is simple. More specifically, due to its own characteristics, the insulating parts have poor resistance to moisture and heat durability. At the same time, the printing of insulating parts increases the difficulty of the process. For back-contact cells with multiple grid lines, it is difficult to control the accuracy of setting insulating parts. Therefore, in this application, a through hole 111 only covers the collector grid lines and bus grid lines of the same polarity. There is no need to set insulating parts on the collector grid lines and bus grid lines of another polarity. The life of the photovoltaic module can be improved, the process is simple, the yield is higher, and the investment in insulating equipment is reduced, which is more conducive to mass production. The insulating parts mentioned here have good insulating properties, such as insulating glue, etc., and their specific components are not limited.

[0042] For example, Fig. 9 In the figure, the through hole 111 only covers the collector grid lines and bus grid lines of the same polarity, and does not cover the collector grid lines and bus grid lines of another polarity. Therefore, there is no need to set insulating parts on the collector grid lines and bus grid lines of another polarity. The life of the photovoltaic module can be improved, the process is simple, the yield is higher, and the investment in insulating equipment is reduced, which is more conducive to mass production.

[0043] Optional, see Fig. 9 A through hole 111 only covers the collector grid lines and bus grid lines of the same polarity, and the distance d1 between the through hole 111 and the collector grid lines of the other polarity adjacent to the outside thereof is greater than or equal to 0.1 mm. While compatible with process errors, there is no need to set an insulating part on the collector grid lines and bus grid lines of the other polarity, and the risk of short circuit is avoided.

[0044] For example, a through hole 111 only covers the collector grid lines and bus grid lines of the same polarity, and the distance d1 between the through hole 111 and the collector grid lines of another polarity adjacent to its outer side can be 0.1mm, 0.11mm, 0.13mm, 0.15mm, 0.19mm, 0.2mm, 0.21mm, 0.23mm, or 0.25mm.

[0045] Optional, see Figure 2 , Figure 4 , Figure 7 , Figure 8 and Fig. 9 , the back contact cell also includes: a plurality of electrical connection parts 23, which are electrically connected to the busbar lines. Here, the electrical connection parts 23 can be directly arranged on the busbar lines 22 to achieve electrical connection, or in the first direction L1, there can be a certain distance between the electrical connection parts 23 and the busbar lines 22, and the electrical connection between the two is achieved by setting a connecting section, and the present invention does not make any specific limitations on this. For example, the busbar line is located at the edge of the back contact cell in the second direction, and the electrical connection parts 23 can be moved inward appropriately. The electrical connection parts 23 are located in the through hole, that is, the insulating layer 11 includes: a first surface close to the back contact cell 2. The orthographic projection of the electrical connection part on the first surface is the first orthographic projection, and the orthographic projection of the through hole 111 on the first surface is the second orthographic projection. The orthographic projection of the electrical connection part on the first surface refers to: the projection of the electrical connection part on the first surface when the electrical connection part is irradiated with light perpendicular to the first surface. The orthographic projection of the through hole 111 on the first surface may refer to the contour line of the first through hole 111 on the first surface. Refer to Fig. 9 , the first orthographic projection of the electrical connection portion falls within the second orthographic projection of the through hole 111. The distance between the edge of the through hole and the edge of the electrical connection portion in the through hole is greater than or equal to 0.2 mm, that is, the distance d2 between the edge of the first orthographic projection and the edge of the second orthographic projection is greater than or equal to 0.2 mm, that is, the closest distance between the edge of the first orthographic projection and the edge of the second orthographic projection also needs to be greater than or equal to 0.2 mm. Specifically, in the case where the back contact battery cell includes an electrical connection portion, refer to Figure 7 , the bonding material 112 is usually arranged on the electrical connection part, and the electrical connection part is located in the through hole or the first orthographic projection of the electrical connection part falls into the second orthographic projection of the through hole 111, which means that the through hole is larger than the electrical connection part, and there is still a gap greater than or equal to 0.2mm at the position where the two are closest, so that the bonding material 112 can be located in the through hole 111 as much as possible, and the contact area between the bonding material 112 and the conductive layer 12 is as large as possible, and the power loss is small. More specifically, once the through hole 111 is smaller than the size of the electrical connection part, it will inevitably cause a part of the electrical connection part area to be located outside the through hole after the electrical connection part and the through hole intersect, which means that this part of the area will not be able to form an interconnection with the conductive layer through the bonding material, which will lead to a reduction in the contact area and cause power loss. According to calculations, when the through hole of the insulating layer covers the area of ​​the electrical connection part, every 5% reduction in the area of ​​the electrical connection part may generate a power loss of 0.2W (watt) to 0.5W, so it is ensured that the through hole of the insulating layer contains the electrical connection part and the through hole is at least 0.2mm larger than the electrical connection part, which can reduce the power loss as much as possible. It should be noted that the electrical connection portion here can be an electrode disk, etc., and there is no specific limitation on this.

[0046] For example, the back contact cell also includes: a plurality of electrical connections electrically connected to the busbar lines. The electrical connection is located in the through hole, and the distance between the edge of the through hole and the edge of the electrical connection in the through hole is d2, or the first orthographic projection of the electrical connection falls within the second orthographic projection of the through hole 111, and the distance between the edge of the first orthographic projection and the edge of the second orthographic projection is d2. The d2 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.8mm, 1mm.

[0047] Optional, see Fig.10 The edge of the conductive layer 12 is a broken line or non-arc shape, which can ensure the cumulative relationship during current transmission and further improve the current transmission efficiency.

[0048] Optionally, in the first direction L1, the ratio of the size of the through hole 111 to the size of the electrical connection portion is 1.1 to 3; and / or, in the second direction L2, the ratio of the size of the through hole 111 to the size of the electrical connection portion is 1.1 to 3. That is to say, in the first direction L1 and the second direction L2, the size of the through hole 111 is larger than the size of the electrical connection portion, the electrical connection portion is located in the through hole, or the first orthographic projection of the electrical connection portion falls within the second orthographic projection of the through hole 111. In the first direction L1, the ratio of the size of the through hole 111 to the size of the electrical connection portion is 1.1 to 3; and / or, in the second direction L2, the ratio of the size of the through hole 111 to the size of the electrical connection portion is 1.1 to 3, the through hole 111 has enough redundant space to accommodate the position error of the arrangement, and can ensure that the bonding material 112 can pass through the through hole 111 as completely as possible, can ensure the quality of interconnection, and avoid the risk of short circuit. The bonding material 112 will basically not be offset, and the through hole 111 will not be too large to avoid the risk of short circuit. It should be noted that there is no specific limitation on whether the ratio of the size of the through hole 111 to the size of the electrical connection portion in the first direction L1 is equal to the ratio of the size of the through hole 111 to the size of the electrical connection portion in the second direction L2, and they may be equal or unequal.

[0049] For example, in the first direction L1, the ratio of the size of the through hole 111 to the size of the electrical connection portion may be 1.1, 1.2, 1.5, 1.7, 1.8, 1.9, 2, 2.2, 2.5, 2.7, 2.8, 2.93, 3. For example, in the second direction L2, the ratio of the size of the through hole 111 to the size of the electrical connection portion may be 1.1, 1.3, 1.4, 1.5, 1.6, 1.8, 2, 2.1, 2.3, 2.5, 2.6, 2.9, 3.

[0050] Optionally, the insulating layer includes: a first surface close to the back contact battery cell, the distance between the orthographic projection of the geometric center of the through hole on the first surface and the orthographic projection of the geometric center of the electrical connection part in the through hole on the first surface is less than or equal to 1 mm, that is, the first orthographic projection of the electrical connection part falls within the second orthographic projection of the through hole 111, and the distance between the geometric center of the first orthographic projection and the geometric center of the second orthographic projection is less than or equal to 1 mm, so that the bonding material 112 is located in the through hole 111 as much as possible, the contact area between the bonding material 112 and the conductive layer 12 is as large as possible, the power loss is small, the through hole 111 has enough redundant space to accommodate the position error of the arrangement, and can ensure that the bonding material 112 can pass through the through hole 111 as completely as possible, the interconnection quality can be guaranteed, and the short-circuit efficiency is also low. The bonding material 112 will basically not shift, and the short-circuit risk is low. More specifically, before lamination, the geometric center of the first orthographic projection and the geometric center of the second orthographic projection may be offset or not offset. For example, 95% of the area of ​​the first orthographic projection before lamination is located within the second orthographic projection. After lamination or in the photovoltaic module, the distance between the geometric center of the first orthographic projection and the geometric center of the second orthographic projection may be about 0.5 mm. For another example, the first orthographic projection of the electrical connection portion falls within the second orthographic projection of the through hole 111, and the distance between the geometric center of the first orthographic projection and the geometric center of the second orthographic projection may be 0, 0.05 mm, 0.1 mm, 0.2 mm, 0.mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 1 mm. Here, the distance between the geometric center of the first orthographic projection and the geometric center of the second orthographic projection is 0, which means that the geometric center of the first orthographic projection and the geometric center of the second orthographic projection coincide.

[0051] Optionally, the electrical connection portion is located in the through hole, and the first orthographic projection of the electrical connection portion falls within the second orthographic projection of the through hole 111, and the ratio of the area of ​​the second orthographic projection to the area of ​​the first orthographic projection is greater than or equal to 1.3. The through hole 111 has sufficient redundant space to accommodate the position error of the arrangement of the sheets, and can ensure that the bonding material 112 passes through the through hole 111 as completely as possible, the interconnection quality can be guaranteed, the effective transmission of the current can be guaranteed, and the short-circuit efficiency is also low. The bonding material 112 will basically not be offset, and the risk of short circuit is low. For example, the ratio of the area of ​​the second orthographic projection to the area of ​​the first orthographic projection can be 1.3, 1.5, 1.7, 1.8, 1.9, 2, 2.2, 2.5, 2.7, 2.8, 2.9, 3.

[0052] Optional, see Figure 7, the bonding material 112 is arranged on the second surface of the electrical connection part close to the insulating layer 11, and the bonding material 112 can be arranged on the second surface of the electrical connection part close to the insulating layer 11 by printing, dispensing, etc. The orthographic projection of the bonding material 112 on the second surface and its extended surface is the third orthographic projection, and the orthographic projection of the bonding material 112 on the second surface and its extended surface refers to: the bonding material is irradiated with light perpendicular to the second surface and its extended surface, and the projection of the bonding material on the second surface and its extended surface. The third orthographic projection is located within the second surface, that is, the bonding material does not exceed the second surface of the electrical connection part, and the risk of short circuit caused by the offset of the bonding material can be reduced as much as possible. Specifically, once the bonding material exceeds the electrical connection part, the risk of short circuit will be increased. The part of the bonding material that exceeds the electrical connection part will reduce the distance from the heterogeneous grid line, increase the risk of contact with the heterogeneous grid line to form a short circuit, and at the same time, the exceeding part will directly contact the silicon substrate. This part does not have the slurry metal of the back contact battery cell, and the bonding material cannot be welded or infiltrated with the silicon substrate. Therefore, the bonding material that exceeds the electrical connection part may run around during the curing process, causing a more serious short circuit risk. However, it is also required that the area of ​​the bonding material is close to the area of ​​the electrical connection portion for the best result, so as to ensure that the bonding material and the electrical connection portion can have the largest contact area to provide the lowest contact loss.

[0053] It should be noted that in the present application, the shape of the second surface is not specifically limited. For example, the shape of the second surface can be a rectangle, such as a rectangle with chamfers. The chamfers of the rectangle can save slurry. The two perpendicular sides of the rectangle here can be equal or unequal in size, and there is no specific limitation on this. If the aforementioned through hole 111 is a circular hole, its diameter is φ, φ needs to be larger than the perpendicular long sides of the rectangle, and φ needs to be larger than the diagonal of the rectangle. The extended surface of the second surface mentioned in the present application refers to a surface that is roughly coplanar or completely coplanar with the second surface, but larger than the second surface.

[0054] Optional, see Figure 7 , the bonding material 112 is arranged on the second surface of the electrical connection portion close to the insulating layer 11. The orthographic projection of the bonding material 112 on the second surface and its extended surface is the third orthographic projection, and the area of ​​the third orthographic projection is less than or equal to the area of ​​the second surface, that is, the area of ​​the orthographic projection of the bonding material 112 is slightly smaller, reducing the risk of short circuit caused by the offset of the bonding material.

[0055] Optionally, the volume of the bonding material 112 accounts for 9.8% to 80% of the volume of the through hole 111. The content of the bonding material 112 is not too small, and the electrical connection between the busbar line and the conductive layer is more reliable, which is conducive to the effective transmission of current. The content of the bonding material is not too much, avoiding the risk of short circuit caused by the overflow of the bonding material. More specifically, once the volume of the bonding material 112 accounts for more than 80% of the volume of the through hole 111, the bonding material is likely to overflow the through hole. Since the insulating layer cannot form an electrical connection with the bonding material, it may break during the lamination process to form a movable bonding material (forming a movable metal component), which is likely to cause a short circuit. Once the volume of the bonding material 112 accounts for less than 9.8% of the volume of the through hole 111, it will result in insufficient electrical connection area, resulting in greater resistance loss.

[0056] Furthermore, the volume of the bonding material 112 can account for 28% to 78% of the volume of the through hole 111. For example, the volume of the bonding material 112 can account for 9.8%, 10%, 12%, 15%, 20%, %, 28%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 78% of the volume of the through hole 111.

[0057] The present application also provides a photovoltaic system, which may include: a plurality of any of the aforementioned photovoltaic modules, in which the photovoltaic modules may be distributed in an array. For example, the photovoltaic system may be arranged on a building roof, or directly exist as a building roof, etc., and the specific form of the photovoltaic system is not limited. The photovoltaic system has the same or similar beneficial effects as any of the aforementioned photovoltaic modules, and the relevant parts may be referred to each other. In order to avoid repetition, it will not be described here.

[0058] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0059] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A photovoltaic module, characterized in that: include: A conductive back plate, and a back contact cell sheet disposed on the conductive back plate; The back contact cell comprises: a plurality of collector grid lines and a plurality of bus grid lines; the collector grid lines extend along a first direction, and the collector grid lines with different polarities are alternately and spaced along a second direction; the first direction is different from the second direction; the bus grid lines extend along the second direction, and the bus grid lines with different polarities are alternately and spaced along the first direction; the collector grid lines and the bus grid lines with the same polarity are electrically connected; The conductive backplane comprises: a conductive layer, and an insulating layer located between the conductive layer and the back contact cell; a through hole is opened in the insulating layer at a position corresponding to the busbar line, the through hole is filled with a bonding material, and the busbar line is electrically connected to the conductive layer through the bonding material in the through hole; In one back-contact cell region, the ratio of the total number of through holes in a region of the insulating layer corresponding to a column of busbar lines to the total number of columns of busbar lines in one back-contact cell is 0.17 to 3.

2. The photovoltaic module according to claim 1, characterized in that: The total number is 5 to 25.

3. The photovoltaic module according to claim 1, characterized in that: In the first direction, the through hole in the insulating layer at most extends to a position corresponding to a center line of an adjacent bus bar line.

4. The photovoltaic module according to claim 1, characterized in that: One through hole only covers the collector grid lines and the bus grid lines of the same polarity.

5. The photovoltaic module according to claim 4, characterized in that: The distance between the through hole and the collector grid line of another polarity adjacent to the outer side thereof is greater than or equal to 0.1 mm.

6. The photovoltaic module according to claim 1, characterized in that: The back contact cell sheet further comprises: a plurality of electrical connection parts electrically connected to the busbar lines; the electrical connection parts are located in the through holes.

7. The photovoltaic module according to claim 6, characterized in that: A distance between an edge of the through hole and an edge of the electrical connection portion in the through hole is greater than or equal to 0.2 mm.

8. The photovoltaic module according to claim 6, characterized in that: In the first direction, a ratio of a size of the through hole to a size of the electrical connection portion is 1.1 to 3; and / or, In the second direction, a ratio of a size of the through hole to a size of the electrical connection portion is 1.1 to 3.

9. The photovoltaic module according to claim 6, characterized in that: The insulating layer includes: a first surface close to the back contact cell; a distance between an orthographic projection of the geometric center of the through hole on the first surface and an orthographic projection of the geometric center of the electrical connection portion in the through hole on the first surface is less than or equal to 1 mm.

10. The photovoltaic module according to claim 6, characterized in that: The insulating layer includes: a first surface close to the back contact cell; the orthographic projection of the electrical connection portion on the first surface is a first orthographic projection, and the orthographic projection of the through hole on the first surface is a second orthographic projection; the area of ​​the second orthographic projection is greater than or equal to 1.3 in ratio to the area of ​​the first orthographic projection.

11. The photovoltaic module according to claim 6, characterized in that: The bonding material is disposed on the second surface of the electrical connection portion close to the insulating layer; the orthographic projection of the bonding material on the second surface and its extended surface is a third orthographic projection, and the third orthographic projection is located within the second surface.

12. The photovoltaic module according to claim 6, characterized in that: The bonding material is arranged on the second surface of the electrical connection portion close to the insulating layer; the orthographic projection of the bonding material on the second surface and its extended surface is a third orthographic projection, and the area of ​​the third orthographic projection is less than or equal to the area of ​​the second surface.

13. The photovoltaic module according to claim 1, characterized in that: The volume of the bonding material accounts for 9.8% to 80% of the volume of the through hole.

14. A photovoltaic system, characterized in that: include: The photovoltaic module according to any one of claims 1 to 13.

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