Photovoltaic panels and photovoltaic systems

Abstract

The present invention provides a photovoltaic module and a photovoltaic system, and relates to the field of photovoltaic technology. The photovoltaic module includes an insulating member, a conductive back plate and a back contact cell; the back contact cell includes a collector grid line; a junction and a non-junction extending along a second direction and alternately distributed along a first direction, and the junction and the non-junction both include a part of the collector grid line; the conductive back plate includes: a conductive layer, and an insulating layer located between the conductive layer and the back contact cell; a through hole is provided at a position corresponding to at least one junction in the insulating layer; the through hole is filled with a bonding material; a collector grid line of one polarity in the junction is electrically connected to the conductive layer through the bonding material, and an insulating member is provided on the collector grid line of another polarity, and is insulated from the conductive layer through the insulating member; for a through hole, the ratio of the width of the insulating member to the width of the through hole is greater than 1, and less than or equal to 50. The photovoltaic module has a low risk of hidden cracking, is easy to mass produce, has a long service life and a good current collection effect.

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 grid lines of back contact solar 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 that the risk of hidden cracks in existing photovoltaic modules is high and affects the quality and reliability of the photovoltaic modules.

[0006] A first aspect of the present invention provides a photovoltaic module, comprising: an insulating member, a conductive back sheet, and a back contact cell sheet disposed on the conductive back sheet;

[0007] The back contact cell comprises: a plurality of collector grid lines extending along a first direction; the collector grid lines of different polarities are spaced and alternately distributed along a second direction; a junction and a non-junction portion extending along the second direction and alternately distributed along the first direction, the junction and the non-junction portion both comprising a portion of the collector grid lines; the first direction is different from the second direction;

[0008] 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 at least one of the bonding parts; the through hole is filled with a bonding material; a collector grid line of one polarity in the bonding part is electrically connected to the conductive layer through the bonding material, and a collector grid line of another polarity is provided with the insulating member and is insulated from the conductive layer by the insulating member;

[0009] For one of the through holes, a ratio of a width of the insulating member to a width of the through hole is greater than 1 and less than or equal to 50; and a direction of the width is parallel to the first direction.

[0010] First, the present application does not adopt the method of welding with welding strips, but selects a conductive backplane for current conduction. Since welding is basically unnecessary, there is basically no risk of introducing hidden cracks into the back contact cell, and the risk of hidden cracks in the photovoltaic module is low. The back contact cell includes: a plurality of collector grid lines extending along a first direction, and a junction and a non-junction extending along a second direction and alternately distributed along the first direction, the junction and the non-junction both include a portion of the collector grid line, the conductive backplane includes a conductive layer, and an insulating layer located between the conductive layer and the back contact cell, the through holes of the insulating layer are filled with a bonding material, the collector grid line of one polarity in the junction is electrically connected to the conductive layer through the bonding material for current conduction, and the collector grid line of the other polarity is provided with an insulating member, and is insulated from the conductive layer by the insulating member, and the insulating member and the insulating layer avoid the risk of short circuit. Secondly, there is no need to set a bus grid line in the back contact cell of the present application, or the length of the bus grid line is short, and current can be collected mainly through the collector grid line, which reduces costs and simplifies the process. At the same time, in order to minimize the dead zone, the spacing between adjacent collector grid lines of different polarities is small, and the process precision required for opening a single collector grid line is high. Therefore, in the present application, a through hole directly covers multiple collector grid lines and the spacing between them, which can simplify the process. For a through hole, the width of the insulating member needs to be greater than the width of the through hole, which can largely avoid the risk of short circuit caused by the leakage of the collector grid line of the other polarity in the through hole. Therefore, for a through hole, the ratio of the width of the insulating member to the width of the through hole is greater than 1. For a through hole, the ratio of the width of the insulating member to the width of the through hole is greater than 1 and less than or equal to 50. The width of the insulating member is not too large relative to the width of the through hole, which can avoid the reliability problems caused by the reduction of aging resistance, moisture and heat resistance and adhesion due to the excessive size of the insulating member. In addition, because the size of the through hole needs to match the current transmission, it also affects the plastic deformation and bonding properties of the insulating layer. If the width of the through hole is too large, it will also reduce the bonding properties of the insulating layer. At the same time, it is necessary to increase the amount of insulating members used for insulation, thereby increasing the cost. In the present application, the width of the insulating member is not too small relative to the width of the through hole, so as to maintain the good mechanical properties and bonding properties of the insulating layer, which can not only ensure the effective transmission of current, but also effectively reduce the amount of insulating members used and reduce the difficulty of the process. In summary, the photovoltaic modules provided in the present application have achieved a good balance of various factors, with low risk of hidden cracks, low cost, simple process, high yield, and easy mass production. At the same time, they have low short circuit risk, good reliability, long life, and good current collection effect.

[0011] Optionally, for one of the through holes, the ratio of the width of the insulating member to the width of the through hole is greater than 1 and less than or equal to 25. On the basis of ensuring the insulation effect, the amount of the insulating member can be further reduced, and the reliability problems caused by the decrease in aging resistance, moisture and heat resistance and adhesion due to the excessive size of the insulating member can be further avoided, and costs can be further saved.

[0012] Optionally, for one of the through holes, at two opposite ends in the first direction, the insulating member both protrudes from the through hole by at least 0.2 mm, which can accommodate errors in the process and make the photovoltaic module basically free from the risk of short circuit. That is, it is not only easy to meet the process requirements, but also not too wide, thereby reducing the waste of insulating members.

[0013] Optionally, for one of the through holes, the total length of the insulating member accounts for 15% to 75% of the length of the through hole; the direction of the length is parallel to the second direction, which can not only reduce the risk of short circuit, but also the amount of insulating member used is not too much, which can avoid the reliability problems caused by the decline in anti-aging, moisture and heat resistance and adhesion due to the excessive size of the insulating member. In addition, because the size of the through hole needs to match the current transmission, it also affects the plastic deformation and bonding performance of the insulating layer. The excessive length of the through hole will also reduce the bonding performance of the insulating layer. At the same time, it is necessary to increase the amount of insulating members used for insulation, thereby increasing the cost. In the present application, the total length of the insulating member accounts for a proportion of the length of the through hole that is not too small, maintaining the good mechanical properties and bonding properties of the insulating layer. In summary, the photovoltaic module provided by the present application has a low risk of hidden cracks, low cost, simple process, high yield, and is easy to achieve mass production. At the same time, the risk of short circuit is low, the mechanical properties and bonding properties of the insulating layer are good, and the reliability is good and the service life is long.

[0014] Optionally, for one of the through holes, the total area of ​​the insulating member accounts for a proportion of the area of ​​the through hole that is greater than or equal to 12%, which can ensure efficient current extraction while avoiding short circuits. At the same time, the amount of insulating member used is not too much, which can avoid reliability problems caused by the decline in anti-aging, moisture and heat resistance, and adhesion due to the excessive size of the insulating member. In addition, the size of the through hole needs to match the current transmission, and also affects the plastic deformation and bonding performance of the insulating layer. If the area of ​​the through hole is too large, it will also reduce the bonding performance of the insulating layer. At the same time, it is necessary to increase the amount of insulating member used for insulation, thereby increasing the cost. In the present application, the total area of ​​the insulating member accounts for a proportion of the area of ​​the through hole that is not too small, maintaining the good mechanical properties and bonding properties of the insulating layer. At the same time, for one through hole, the total area of ​​the insulating member accounts for a proportion of the area of ​​the through hole that is greater than or equal to 12%, so that the insulating member has an operable process window.

[0015] Optionally, in the portion of the insulating layer corresponding to one of the back contact battery cells, the number of through holes is 9 to 28, and the number of through holes is not too large, thereby maintaining good mechanical properties and adhesion properties of the insulating layer and achieving better current conduction effects, thereby achieving a better balance between current transmission and power.

[0016] Optionally, a first electrical connection portion is provided on the collector grid line in the combining portion that is electrically connected to the conductive layer, and the first electrical connection portion is located in the through hole. By providing the first electrical connection portion, the interconnection effect can be enhanced and the reliability of the electrical connection can be improved.

[0017] Optionally, in the second direction, the first electrical connection portion located in the same through hole is spaced greater than or equal to 0.1 mm from the adjacent insulating member. On the one hand, a larger operating space is reserved for the setting of the insulating member, facilitating the setting of the insulating member; on the other hand, the risk of short circuit can be further reduced.

[0018] Optionally, the first electrical connection portion includes: a first surface close to the conductive layer, the total area of ​​all the first surfaces in one of the through holes accounts for less than or equal to 20% of the area of ​​the through hole, which can not only ensure effective current transmission, but also effectively reduce the use of insulating parts and reduce the difficulty of the process, while also reducing the risk of short circuit.

[0019] Optionally, the first electrical connection portion includes: a first surface close to the conductive layer, the bonding material is arranged on the first surface; the orthographic projection of the bonding material on the first surface and its extended surface is the first orthographic projection, the first orthographic projection is located within the first surface, and the bonding material does not exceed the first surface of the first electrical connection portion, which can minimize the risk of short circuit caused by the offset of the bonding material. Specifically, once the bonding material exceeds the first electrical connection portion, the risk of short circuit will increase. The portion of the bonding material that exceeds the first electrical connection portion 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 portion will directly contact the silicon substrate. This portion 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 first electrical connection portion 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 the best for the area of ​​the first surface close to the first electrical connection portion, so that the bonding material and the first electrical connection portion can have the largest contact area to provide the lowest contact loss.

[0020] Optionally, the first electrical connection portion includes: a first surface close to the conductive layer, the bonding material is arranged on the first surface; the orthographic projection of the bonding material on the first surface and its extended surface is a first orthographic projection, and the area of ​​the first orthographic projection is less than or equal to the area of ​​the first surface, which can reduce the risk of short circuit caused by offset of the bonding material.

[0021] Optionally, the ratio of the width of the through hole to the length of the first electrical connection part in the through hole is (1.1 to 10): 1; the direction of the length of the first electrical connection part is parallel to the first direction. On the one hand, while being compatible with the alignment error, it can still be ensured that the first electrical connection part is covered in the through hole as much as possible to improve the current collection effect; on the other hand, the width of the through hole is not too large, so as to avoid problems such as decreased adhesion due to the excessive size of the through hole, because an overly large through hole will reduce the bonding area between the insulating layer and the back contact battery 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, and at the same time increase the difficulty of the process.

[0022] Optionally, the collector grid line includes: a first collector grid line continuously arranged from one end of the back contact battery cell to the other end along the first direction, the first collector grid line does not need to be disconnected in the middle, there is basically no dead zone in its extension direction, and the setting efficiency of the first collector grid line is higher.

[0023] Optionally, the back contact cell further comprises: a plurality of busbar lines extending along the second direction; busbar lines of different polarities are alternately and spaced apart along the first direction; the collector grid line comprises: a second collector grid line electrically connected to the busbar line of the same polarity; the busbar line extends to a position where the second collector grid line is arranged;

[0024] In the second direction, the through hole extends to the area corresponding to the bus grid line; the bus grid line in the through hole and the second collector grid line with the same polarity as the bus grid line are electrically connected to the conductive layer through the bonding material, and the second collector grid line with a different polarity from the bus grid line is provided with the insulating member and is insulated from the conductive layer by the insulating member. The present application is compatible with the technical solution with the bus grid line, and the setting method of the collector grid line is flexible and diverse.

[0025] Optionally, in the second direction, the plurality of collector grid lines are divided into at least two collector grid line groups by the bus grid line;

[0026] One of the through holes only covers one of the collector grid lines and extends to the area corresponding to the bus grid line adjacent to the collector grid line group. For the insulating layer, the area of ​​a single through hole becomes smaller, which is more conducive to maintaining the supporting strength of the insulating layer and also helps to reduce the occurrence of deformation drift of each structure in a single through hole.

[0027] Optionally, in the first direction, the insulating member at most extends to a position corresponding to a center line of an adjacent busbar line, which can reduce waste of insulating members, prevent excessive use of insulating members, and avoid reliability problems caused by decreased aging resistance, moisture and heat resistance, and adhesion due to excessive size of the insulating member; and / or,

[0028] In the first direction, the through hole at most extends to a position corresponding to a center line of an adjacent busbar line, further reducing the risk of short circuit.

[0029] Optionally, in the portion of the insulating layer corresponding to one of the back-contact battery cells, the number of the through holes along the first direction is less than or equal to the total number of columns of bus bars in one of the back-contact battery cells, and greater than or equal to half of the total number of columns of bus bars in one of the back-contact battery cells. This is the result of a good balance among the production efficiency of the insulating layer, the cost of insulating material, and the difficulty of the process.

[0030] Optionally, the back contact cell further comprises: a plurality of second electrical connection portions, electrically connected to the busbar lines and located in the through holes;

[0031] In the second direction, the second electrical connection portion located in the same through hole is spaced greater than or equal to 0.1 mm from the adjacent insulating member. On the one hand, a larger operating space is reserved for the setting of the insulating member, which facilitates the setting of the insulating member. On the other hand, the risk of short circuit can be further reduced.

[0032] Optionally, the plurality of second electrical connection portions include: an edge second electrical connection portion close to an edge of the back contact cell in the second direction;

[0033] In the second direction, the through hole extends to the outside of the area corresponding to the edge second electrical connection part, and on the side close to the edge of the back contact battery cell, the distance between the through hole and the edge second electrical connection part is greater than or equal to 0.3 mm. While tolerating the alignment error, it can be ensured that the edge second electrical connection part is located in the through hole, thereby improving the current collection effect.

[0034] Optionally, the ratio of the width of the through hole to the length of the second electrical connection portion in the through hole is (1.1 to 10): 1; the direction of the length of the second electrical connection portion is parallel to the first direction. On the one hand, while being compatible with the alignment error, it can still be ensured that the second electrical connection portion is covered in the through hole as much as possible to improve the current collection effect; on the other hand, the width of the through hole is not too large to avoid problems such as decreased adhesion due to the excessive size of the through hole. Because an oversized through hole will reduce the bonding area between the insulating layer and the back contact battery cell, it will also weaken the overall strength of the insulating layer and cause its plastic deformation. Plastic deformation may also cause the insulation of the insulating layer to decrease, causing the risk of short circuit, and at the same time increase the difficulty of the process.

[0035] Optionally, the second electrical connection portion includes: a second surface close to the conductive layer, the bonding material is arranged on the second surface; the orthographic projection of the bonding material on the second surface and the extended surface thereof is a second orthographic projection;

[0036] The second orthographic projection is located within the second surface, and the bonding material does not exceed the second surface of the second electrical connection part, which can minimize the risk of short circuit caused by the offset of the bonding material. Specifically, once the bonding material exceeds the second electrical connection part, the risk of short circuit will increase. The portion of the bonding material that exceeds the second electrical connection part will reduce the distance from the opposite-sex grid line, increasing the risk of contact with the opposite-sex grid line to form a short circuit. At the same time, the exceeding portion will directly contact the silicon substrate. This portion 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 second electrical connection part may run around during the curing process, causing a more serious short circuit risk; and / or,

[0037] The area of ​​the second orthographic projection is smaller than or equal to the area of ​​the second surface, which can reduce the risk of short circuit caused by the offset of bonding materials.

[0038] A second aspect of the present invention provides a photovoltaic system, comprising: a plurality of any of the aforementioned photovoltaic modules.

[0039] The above-mentioned photovoltaic modules and photovoltaic systems have the same or similar beneficial effects, and will not be described in detail here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] 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.

[0041] Figure 1A schematic front cross-sectional view of a photovoltaic module in an embodiment of the present invention is shown;

[0042] Figure 2 A partial structural schematic diagram of a back contact cell in an embodiment of the present invention is shown;

[0043] Figure 3 A schematic diagram of the coordination structure of a back contact cell and an insulating layer in an embodiment of the present invention is shown;

[0044] Figure 4 A schematic structural diagram of an insulating layer in an embodiment of the present invention is shown;

[0045] Figure 5 A schematic structural diagram of a conductive layer in an embodiment of the present invention is shown;

[0046] Figure 6 A schematic diagram of the coordination structure of a conductive layer and an insulating layer in an embodiment of the present invention is shown;

[0047] Figure 7 A schematic diagram showing a matching structure of a back contact battery sheet and an insulating member in an embodiment of the present invention is shown;

[0048] Figure 8 A schematic diagram showing the matching of an insulating layer and an insulating member in an embodiment of the present invention is shown;

[0049] Fig. 9 A schematic diagram showing the coordination of the insulating layer, the insulating member, the back contact cell and the conductive layer in an embodiment of the present invention is shown;

[0050] Fig.10 A schematic diagram showing the structure of another insulating layer in an embodiment of the present invention is shown;

[0051] Fig.11 A schematic diagram of the matching structure of another insulating layer and insulating member in an embodiment of the present invention is shown;

[0052] Fig.12 Another schematic diagram of the matching structure of the back contact battery sheet and the insulating member in the embodiment of the present invention is shown;

[0053] Fig.13 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.

[0054] Description of the accompanying drawings:

[0055] 1-conductive backplane, 11-insulating layer, 111-through hole, 112-bonding material, 12-conductive layer, 13-rear packaging film, 14-backplane, 2-back contact battery cell, 3-front packaging film, 4-glass, 5-insulating member, 21-first electrical connection portion, 22-first collector grid line, 23-bus grid line, 24-second collector grid line, 25-collector grid line group, 26-second electrical connection portion. DETAILED DESCRIPTION

[0056] 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.

[0057] 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 further include: a front encapsulation 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. The photovoltaic module may further include an insulating member 5 which may function as an electrical barrier.

[0058] Reference Figure 2 , Figure 3 , Figure 7 , Fig. 9 and Fig.12 The back contact cell 2 includes: a plurality of collector grid lines extending along the first direction L1. The collector grid lines of different polarities are spaced and alternately distributed along the second direction L2. One of the collector grid lines of different polarities is an N-type collector grid line and the other is a P-type collector grid line. 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.

[0059] The back contact cell sheet 2 may also include: a bonding portion and a non-bonding portion extending along the second direction L2 and alternately distributed along the first direction L1, wherein both the bonding portion and the non-bonding portion include a portion of the collector grid line, and for the same collector grid line, the bonding portion and the non-bonding portion include different portions of the collector grid line. The bonding portion and the non-bonding portion here also both include the intervals between adjacent collector grid lines. The bonding portion here will be located in the through hole of the insulating layer, and the non-bonding portion will be located at a position where no through hole is provided in the insulating layer. The alternation here means that in the first direction L1, a bonding portion is followed by a non-bonding portion and then by a bonding portion. For example, Figure 3 In the figure, the back contact cell sheet 2 includes 10 bonding parts and 11 non-bonding parts, and in the first direction L1, the bonding parts and the non-bonding parts are alternately distributed. The back contact cell sheet here can be a whole cell, or a half cell, a three-piece cell, a four-piece cell, etc., without specific limitation.

[0060] 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.

[0061] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 6 , Figure 8 , Figures 9 to 11 In the insulating layer 11, a through hole 111 is provided at a position corresponding to at least one of the aforementioned joints, and there is no limitation on how many joints a through hole corresponds to. Figure 3 , Fig. 9 In the insulating layer 11, a through hole 111 is provided at a position corresponding to one of the aforementioned joints. The relative size of the length of the through hole 111 along the second direction L2 and the width thereof along the first direction L1 is not specifically limited. For example, in the case where a through hole 111 is provided at a position corresponding to one of the aforementioned joints in the insulating layer 11, the length of the through hole 111 along the second direction L2 may be greater than the width thereof along the first direction L1. Figure 3 The through hole 111 can expose a portion of the collector grid line in at least one of the combined parts. 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.

[0062] Reference Figure 1 The through hole 111 is filled with a bonding material 112, which has a good conductive effect. The bonding material 112 can be solder paste, conductive glue, etc. The composition of the bonding material 112 can be selected from: silver, copper, lead, bismuth, zinc, nickel and other metal parts. The specific material of the bonding material 112 is not limited. The collector grid line of one polarity in the bonding part in the through hole is electrically connected to the conductive layer 12 through the bonding material 112 to conduct the current. The collector grid line of another polarity in the bonding part is provided with an insulating member 5 and is insulated from the conductive layer 12 by the insulating member 5. That is, the collector grid line of another polarity in the bonding part is shielded by the insulating member 5, avoiding the risk of short circuit, and the other areas of the back contact battery cell 2 are in contact with the insulating layer 11 to avoid short circuit and power loss. At the same time, the portion of the insulating layer 11 close to the back contact cell in the thickness direction will be bonded to the corresponding position of the back contact cell. In this application, the welding method of the welding strip is not adopted, but the conductive back plate 1 is selected for current conduction. Because this application basically does not require welding, there is basically no risk of introducing hidden cracks to the back contact cell and the photovoltaic module. 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 insulating member here has a good insulating effect and may be an insulating glue, etc., and its specific composition is not limited.

[0063] For example, refer to Fig. 9 , from left to right, in the first joint, the collector grid line of one polarity is electrically connected to the conductive layer through the bonding material, and in the first joint, the collector grid line of the other polarity is provided with an insulating member 5 to be insulated from the conductive layer. If the collector grid line provided with the insulating member 5 in the first joint is an N-type collector grid line, then the collector grid line electrically connected to the conductive layer in the first joint is a P-type collector grid line. Fig. 9 In the figure, from left to right, in the second joint, the collector grid line of one polarity is electrically connected to the conductive layer through the bonding material, and in the second joint, the collector grid line of the other polarity is provided with an insulating member 5 to be insulated from the conductive layer. Then, the collector grid line provided with the insulating member 5 in the second joint is a P-type collector grid line, and the collector grid line electrically connected to the conductive layer in the second joint is an N-type collector grid line. Fig. 9 , from left to right, in the third joint, the collector grid line of one polarity is electrically connected to the conductive layer through the bonding material, and in the third joint, the collector grid line of the other polarity is provided with an insulating member 5 to be insulated from the conductive layer. If the collector grid line provided with the insulating member 5 in the third joint is an N-type collector grid line, then the collector grid line electrically connected to the conductive layer in the third joint is a P-type collector grid line. Fig. 9The 10 combining parts are further arranged according to the arrangement of the first combining part to the third combining part here, so as to realize current conduction.

[0064] In the present application, in order to minimize the dead zone, the interval between adjacent collector grid lines is small, such as less than 1 mm. The process precision required for opening a single collector grid line is high. Therefore, in the present application, a through hole 111 directly covers multiple collector grid lines and the intervals between them, which can simplify the process.

[0065] The width of the insulating member 5 and the width of the through hole 111 are both parallel to the first direction L1. For a through hole, the width of the insulating member 5 needs to be greater than the width of the through hole 111, which can largely avoid the risk of short circuit caused by the collector grid line of the other polarity leaking out of the through hole, so for a through hole, the ratio of the width of the insulating member to the width of the through hole is greater than 1. More specifically, if the insulating member 5 is too small relative to the width of the through hole 111, since the through hole 111 will expose the underlying conductive layer, and the collector grid line of the back contact battery cell is above the insulating layer, the exposed conductive layer will directly contact the collector grid line of the back contact battery cell. In addition, when an offset occurs during the process, the opposite collector grid line not covered by the insulating member will contact the underlying conductive layer, forming a hard contact and causing a short circuit. Therefore, in the present application, for a through hole, the ratio of the width of the insulating member 5 to the width of the through hole 111 is greater than 1, which can reduce the short circuit phenomenon.

[0066] For a through hole, the ratio of the width of the insulating member 5 to the width of the through hole 111 is greater than 1 and less than or equal to 50. Specifically, since the insulating member can be a material such as organic glue, its moisture and heat resistance has a certain upper limit, so too much insulating member content will greatly reduce the long-term reliability of the component. In the present application, the width of the insulating member 5 is not too large relative to the width of the through hole 111, which can avoid the reliability problems caused by the reduction of aging resistance, moisture and heat resistance and adhesion due to the excessive size of the insulating member 5. In addition, because the size of the through hole 111 needs to match the current transmission, it also affects the plastic deformation and bonding properties of the insulating layer. If the width of the through hole is too large, it will also reduce the bonding properties of the insulating layer. At the same time, it is necessary to increase the amount of insulating members used for insulation, thereby increasing the cost. In the present application, the width of the insulating member 5 is not too small relative to the width of the through hole 111, so as to maintain the good mechanical properties and bonding properties of the insulating layer. In summary, the photovoltaic module provided by the present application has a low risk of hidden cracks, low cost, simple process, high yield, and is easy to mass produce. At the same time, it has a low risk of short circuits, good reliability and a long lifespan.

[0067] For example, for one through hole, the ratio of the width of the insulating member 5 to the width of the through hole 111 may be 1.001, 1.01, 1.02, 1.09, 1.1, 1.2, 1.33, 1.5, 1.4, 2, 5, 8, 10, 14, 20, 25, 30, 35, 40, 45, 50. For another example, for one through hole, the width of the through hole 111 may be 1.1 mm to 2.5 mm, and the width of the insulating member 5 may be 1.21 mm to 125 mm. For another example, for one through hole, the width of the through hole 111 may be 0.4 mm, 0.8 mm, etc.

[0068] Furthermore, for a through hole, the ratio of the width of the insulating member 5 to the width of the through hole 111 is greater than 1 and less than or equal to 25. On the basis of ensuring the insulation effect, the amount of the insulating member 5 is further reduced, and the reliability problems caused by the decrease in anti-aging, moisture and heat resistance and adhesion due to the excessive size of the insulating member 5 are further avoided, and costs can be further saved.

[0069] For example, for one through hole, the ratio of the width of the insulating member 5 to the width of the through hole 111 may be 1.01, 3, 9, 12, 18, 20, 21, 22, 23, 24, 25, 7, 8.5, 16, 18, 1.067, 1.071, 1.077, or 1.057.

[0070] It should be noted that the shape of the through hole 111 can be a regular shape or an irregular shape. For example, the through hole 111 can be a rectangular through hole, or an oblong hole, or a rectangular through hole with chamfers, and a through hole composed of multiple segments, wavy lines, and arc lines can also be used. For each through hole 111 in the insulating layer 11 of the photovoltaic module, the size and shape of different through holes 111 may be slightly different, and the width of the insulating member arranged on different collector grid lines may also be slightly different, but for the same through hole, the ratio of the width of the insulating member 5 to the width of the through hole 111 is within the above range. If the widths of the various insulating members for the same through hole are slightly different, the width of the insulating member 5 mentioned here can be the average of the widths of several insulating members for the same through hole. In the case where the widths of a through hole 111 are different at different positions, the width of the through hole 111 mentioned in this application can be the average of the widths of several positions in the through hole 111, and the selection of several positions is not limited here, and the number of several positions is not limited. For example, the number of positions here can be 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0071] It should be noted that the back contact cell 2 of the present application may be a back contact cell without busbars or with fewer busbars, which can reduce silver paste loss, improve battery efficiency and component power, and other advantages, and can enter the mass production stage more quickly. In the present application, the laying area of ​​the insulating member may be smaller than the coverage area of ​​the insulating layer, and the insulating layer and the insulating member can cooperate to play a good insulating role.

[0072] Optional, see Figure 8 , Fig. 9 and Fig.11 For a through hole, at two opposite ends in the first direction L1, the insulating member 5 exceeds the through hole 111 by at least 0.2 mm, that is, for the same through hole, the width of the insulating member 5 at the left and right ends is at least 0.2 mm larger than the width of the through hole 111, which can accommodate errors in the process, so that the photovoltaic module has basically no risk of short circuit, that is, it is not only easy to meet the process requirements, but also not too wide, which can reduce the waste of insulating members.

[0073] For example, for one through hole, at two opposite ends in the first direction L1, the insulating member 5 extends beyond the through hole 111 by, for example, 0.2 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.1 mm, 1.2 mm, 1.5 mm, 5 mm, 2 mm, 2.5 mm, or 4 mm.

[0074] Optional, see Figure 7 , Figure 8 and Fig. 9 For a through hole, the total length of the insulating member 5 accounts for 15% to 75% of the length of the through hole 111. The direction of the length is parallel to the second direction L2, that is, from the direction of the length. Not only can the short circuit risk be reduced, but also the amount of the insulating member is not too much, which can avoid the reliability problems caused by the decline in anti-aging, moisture and heat resistance and adhesion due to the excessive size of the insulating member 5. In addition, because the size of the through hole 111 needs to match the current transmission, it also affects the plastic deformation and bonding performance of the insulating layer. The excessive length of the through hole will also reduce the bonding performance of the insulating layer. At the same time, it is necessary to increase the amount of insulating members used for insulation, thereby increasing the cost. In this application, the total length of the insulating member 5 accounts for the length of the through hole 111. The proportion is not too small, maintaining the good mechanical properties and bonding properties of the insulating layer. In summary, the photovoltaic module provided by the present application has a low risk of hidden cracks, low cost, simple process, high yield, and is easy to achieve mass production. At the same time, the short circuit risk is low, the mechanical properties and bonding properties of the insulating layer are good, and the reliability is good and the service life is long. For a through hole, the total length of the insulating member 5 refers to the sum of the lengths of the insulating members 5 on all collector grid lines of the same polarity in a joint portion in the through hole. The length of the insulating member 5 is also parallel to the second direction L2.

[0075] Further, for one through hole, the total length of the insulating member 5 may account for 30% to 60% of the length of the through hole 111. For example, for one through hole, the total length of the insulating member 5 may account for 15%, 19%, 20%, 22.5%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% of the length of the through hole 111.

[0076] Optionally, for a through hole, the total area of ​​the insulating member 5 accounts for a proportion of the area of ​​the through hole 111 that is greater than or equal to 12%. Specifically, the design of the insulating member 5 is interrelated with the design of the through hole 111. The insulating member 5 is to insulate and isolate the opposite collector grid lines, and the through hole 111 is designed to allow the current on the collector grid lines to be extracted through the through hole 111 and to avoid short circuits in the through hole 111. Therefore, the areas of the two are within the above-mentioned ratio range, which can ensure that the current can be efficiently extracted while avoiding short circuits. At the same time, the amount of the insulating member is not too much, which can avoid the reliability problems caused by the decline in anti-aging, moisture and heat resistance and adhesion caused by the excessive size of the insulating member 5. In addition, the size of the through hole 111 needs to match the current transmission, and also affects the plastic deformation and bonding performance of the insulating layer. The excessive area of ​​the through hole will also reduce the bonding performance of the insulating layer, and at the same time, it is necessary to increase the amount of the insulating member used for insulation, thereby increasing the cost. In this application, the total area of ​​the insulating member 5 accounts for a proportion of the area of ​​the through hole 111 that is not too small, maintaining the good mechanical properties and bonding properties of the insulating layer. Meanwhile, for one through hole, the ratio of the total area of ​​the insulating member 5 to the area of ​​the through hole 111 is greater than or equal to 12%, so that the insulating member 5 has an operable process window.

[0077] For example, for one through hole, the ratio of the total area of ​​the insulating member 5 to the area of ​​the through hole 111 may be 12%, 14%, 15%, 16.3%, 18%, 20%, 22%, 25%, 26.2%, 27%, 28%, or 30%.

[0078] Optionally, in the portion of the insulating layer 11 corresponding to a back-contact battery cell 2, the number of through holes 111 is 9 to 28. Specifically, in the portion of the insulating layer 11 corresponding to a back-contact battery cell 2, if the number of through holes 111 is too small, it is not conducive to the transmission of current. If the number is too large, it will affect the length of the collector grid line electrically connected to the conductive backplane, causing power loss. In addition to the need to match the current transmission, the through holes 111 also affect the plastic deformation and bonding properties of the insulating layer. Too many through holes will also reduce the bonding properties of the insulating layer, and at the same time, it is necessary to increase the amount of insulating parts used for insulation, thereby increasing costs. In the present application, the number of through holes 111 is not too large, maintaining the good mechanical properties and bonding properties of the insulating layer. Furthermore, in the portion of the insulating layer 11 corresponding to a back-contact battery cell 2, the number of through holes 111 is 16 to 22, so that current transmission and power are better balanced.

[0079] For example, in the portion of the insulating layer 11 corresponding to a back contact battery cell 2, the number of through holes 111 can be 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28.

[0080] Optional, see Figure 2 , Figure 3 , Figure 7 , Fig. 9 , Fig.12 The collector grid line electrically connected to the conductive layer in the joint may be provided with a first electrical connection portion 21, and the first electrical connection portion 21 may be a thickened section of the collector grid line itself, or a separately provided electrical connection portion. In the case where the first electrical connection portion 21 is a thickened section of the collector grid line itself, the line width of the remaining portion of the collector grid line is smaller than the line width of the first electrical connection portion 21. The first electrical connection portion 21 is located in the through hole 111, and the collector grid line may be connected to the conductive layer through the first electrical connection portion 21 to increase the current collection capability.

[0081] The widths of a through hole 111 at various positions may be equal or unequal. For through holes with equal widths at various positions, the minimum width is the width of the through hole itself. For through holes with unequal widths at some positions, the minimum width is the minimum size of the through hole in the first direction L1. The first electrical connection portion 21 located in the through hole 111 here may mean that the minimum width of the through hole 111 is greater than the maximum length of the first electrical connection portion 21 in the through hole 111, and the direction in which the length of the first electrical connection portion 21 is parallel to the first direction L1, so that the first electrical connection portion 21 is covered in the through hole 111 as much as possible to improve the current collection effect. Moreover, at the two opposite ends in the first direction L1, the insulating member 5 exceeds the adjacent first electrical connection portion 21, so that in the first direction L1, the insulating member 5 can well isolate the first electrical connection portion 21 and the adjacent collector grid line, which can largely avoid the short circuit problem caused by the contact between the first electrical connection portion 21 and the adjacent collector grid line.

[0082] Optionally, in the second direction L2, the first electrical connection portion 21 located in the same through hole 111 is spaced from the adjacent insulating part 5 by a distance greater than or equal to 0.1 mm. On the one hand, a larger operating space is reserved for the setting of the insulating part, which facilitates the setting of the insulating part. On the other hand, the risk of short circuit can be further reduced.

[0083] For example, in the second direction L2, the spacing between the first electrical connection portion 21 located in the same through hole 111 and the adjacent insulating member 5 may be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, or 0.5 mm.

[0084] Optionally, the first electrical connection portion 21 includes: a first surface close to the conductive layer, the total area of ​​all first surfaces in a through hole 111 accounts for less than or equal to 20% of the area of ​​the through hole 111. Specifically, the size of the first surface affects the amount of bonding material thereon. If the first surface is too large, the bonding material may be more, and the bonding material may have the risk of overflowing the through hole, which will increase the risk of short circuit. In addition, the area of ​​the through hole 111 needs to match the current transmission, and also affects the plastic deformation and bonding performance of the insulating layer 11. If the area of ​​the through hole is too large, it will also reduce the bonding performance of the insulating layer, and at the same time, it is necessary to increase the amount of insulating parts used for insulation, thereby increasing the cost. In the present application, the total area of ​​the first surface of the first electrical connection portion is less than or equal to 20% of the area of ​​the through hole, which can not only ensure the effective transmission of current, but also effectively reduce the amount of insulating parts used, and reduce the difficulty of the process, and at the same time reduce the risk of short circuit.

[0085] For example, the total area of ​​all first surfaces in a through hole 111 may account for 20%, 18%, 14%, 13%, 10%, 8%, 5%, 3%, 2%, 1%, 0.5%, 0.1%, or 0.01% of the area of ​​the through hole 111.

[0086] Optionally, the bonding material 112 is disposed on the first surface of the first electrical connection portion 21 close to the conductive layer, and the bonding material 112 can be disposed on the first surface of the first electrical connection portion 21 close to the conductive layer by printing, dispensing, etc. The orthographic projection of the bonding material 112 on the first surface and its extended surface is the first orthographic projection, and the orthographic projection of the bonding material 112 on the first surface and its extended surface refers to: the bonding material is irradiated with light perpendicular to the first surface and its extended surface, and the projection of the bonding material on the first surface and its extended surface. The first orthographic projection is located within the first surface, that is, the bonding material does not exceed the first surface of the first electrical connection portion 21, which can minimize the risk of short circuit caused by the offset of the bonding material. Specifically, once the bonding material exceeds the first electrical connection, the risk of short circuit will increase. The portion of the bonding material that exceeds the first electrical connection will reduce the distance from the opposite-sex grid line, increasing the risk of contact with the opposite-sex grid line and causing a short circuit. At the same time, the portion that exceeds will directly contact the silicon substrate. This portion 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 first electrical connection 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 the best area close to the first surface of the first electrical connection, so as to ensure that the bonding material and the first electrical connection can have the largest contact area to provide the lowest contact loss.

[0087] It should be noted that in the present application, the shape of the first surface is not specifically limited. For example, the shape of the first surface can be a rectangle, such as a rectangle with chamfers. The chamfers can save slurry. The two perpendicular sides of the rectangle here can be equal or unequal in size, and no specific limitation is made. The extended surface of the first surface mentioned in the present application refers to a surface that is substantially coplanar or completely coplanar with the first surface, but larger than the first surface.

[0088] Optionally, the bonding material 112 is disposed on the first surface of the first electrical connection portion 21 close to the conductive layer. The orthographic projection of the bonding material 112 on the first surface and its extended surface is the first orthographic projection, and the area of ​​the first orthographic projection is less than or equal to the area of ​​the first 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.

[0089] Optionally, the ratio of the width of the through hole to the length of the first electrical connection portion 21 in the through hole is (1.1 to 10): 1. The direction of the length of the first electrical connection portion 21 is parallel to the first direction L1. On the one hand, while being compatible with the alignment error, it can still be ensured that the first electrical connection portion 21 is covered in the through hole 111 as much as possible to improve the current collection effect. On the other hand, the width of the through hole 111 is not too large to avoid problems such as decreased adhesion due to the excessive size of the through hole 111. Because an oversized through hole 111 will reduce the bonding area between the insulating layer and the back contact cell, it will also weaken the overall strength of the insulating layer 11 and cause its plastic deformation. Plastic deformation may also cause the insulation of the insulating layer to decrease, causing the risk of short circuits, and increasing the difficulty of the process.

[0090] For example, the ratio of the width of the through hole 111 to the length of the first electrical connection portion 21 can be 1.1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 7:1, 8:1, 9:1, or 10:1.

[0091] Optional, see Figure 2 , Figure 3 , Figure 7 , Fig. 9 and Fig.12 The collector grid line includes: a first collector grid line 22 continuously arranged from one end of the back contact cell 2 to the other end thereof along the first direction L1, the first collector grid line 22 does not need to be disconnected in the middle, there is basically no dead zone in its extension direction, and the arrangement efficiency of the first collector grid line 22 is higher. It should be noted that the first collector grid line 22 here also includes an N-type collector grid line and a P-type collector grid line.

[0092] Optional, see Figure 2 , Figure 3 , Figure 7 , Fig. 9 and Fig.12The back contact cell also includes: a plurality of busbar lines 23 extending along the second direction L2. The busbar lines 23 with different polarities refer to N-type busbar lines and P-type busbar lines. The busbar lines 23 with different polarities are alternately and spaced along the first direction L1. The spacing here can avoid short circuits. The alternation here means that in the first direction L1, an N-type busbar line is followed by a P-type busbar line and then by an N-type busbar line. The collector grid line includes: a second collector grid line 24 electrically connected to the busbar line of the same polarity. The second collector grid line 24 here includes: an N-type second collector grid line and a P-type second collector grid line. The N-type second collector grid line is electrically connected to the N-type busbar line, and the P-type second collector grid line is electrically connected to the P-type busbar line. The busbar line extends to the position where the second collector grid line is set, and the busbar line basically does not extend to the position where the first collector grid line 22 is set. The second collector grid lines 24 are intermittently arranged along the first direction L1 from one end of the back contact cell 2 to the other end of the back contact cell 2 .

[0093] Reference Figure 3 , Fig. 9 In the second direction L2, the through hole 111 extends to the area corresponding to the bus grid line, the bus grid line 23 in the through hole and the second collector grid line 24 with the same polarity as the bus grid line 23 are electrically connected to the conductive layer through the bonding material, and the second collector grid line 24 with a different polarity from the bus grid line is provided with an insulating member and is insulated from the conductive layer by the insulating member. For example, Fig. 9 , there is only one column of bus lines in a through hole 111, and the column of bus lines has the same polarity, and the direction of the column is parallel to the second direction L2. Then, the column of bus lines in the through hole, the second collector grid line with the same polarity as the column of bus lines, and the first collector grid line with the same polarity as the column of bus lines are all electrically connected to the conductive layer through a bonding material, and the second collector grid line with a different polarity from the column of bus lines and the first collector grid line with a different polarity from the column of bus lines in the through hole are both provided with insulating parts, and are all insulated from the conductive layer by the insulating parts, thereby avoiding short circuits and ensuring compatibility between different collector grid lines and bus grid lines.

[0094] It should be noted that the line width of the bus grid line here may be greater than the line width of the collector grid line, because the current flowing through the bus grid line may be greater than the current flowing through the collector grid line. There is no specific limitation on the relative size of the line width of the collector grid line and the collector grid line.

[0095] Optional, see Figure 2In the second direction L2, a plurality of collector grid lines are divided into at least two collector grid line groups 25 by the bus grid line 23, and the collector grid line group 25 is composed of at least two collector grid lines that are closely distributed. A through hole 111 only covers one collector grid line group 25 and extends to the area corresponding to the bus grid line adjacent to the collector grid line group 25. Fig.10 and Fig.11 , and then in the second direction L2, the insulating layer 11 has at least two through holes 111, that is, one through hole in the second direction L2 is divided into at least two through holes, and then for the insulating layer 11, the area of ​​a single through hole 111 becomes smaller, which is more conducive to maintaining the support strength of the insulating layer 11, and is also conducive to reducing the occurrence of deformation drift of each structure in the single through hole 111. For example, Figure 2 , Fig.10 , Fig.11 and Fig.12 In the second direction L2, a plurality of collector grid lines are divided into two collector grid line groups 25 by the spaced collector grid lines, and the original single through hole in the second direction L2 is divided into two through holes.

[0096] Optional, see Figures 7 to 9 and Fig.12 In the first direction L1, the insulating member 5 extends at most to the position corresponding to the center line of two adjacent bus bars, which can reduce the waste of the insulating member 5 and prevent the use of too much insulating member, thereby avoiding reliability problems caused by the decrease in aging resistance, moisture and heat resistance, and adhesion due to the excessive size of the insulating member 5.

[0097] Optional, see Figure 3 and Fig. 9 In the first direction L1, the through hole 111 at most extends to the position corresponding to the center line of two adjacent bus grid lines, further reducing the risk of short circuit. Specifically, in the first direction L1, the two adjacent bus grid lines are the first bus grid line and the second bus grid line of different polarities. The through hole 111 in the insulating layer 11 at most extends to the position corresponding to the center line of the two adjacent bus grid lines. In the case of compatible alignment errors, the through hole 111 is usually basically not exposed at the same time. The grid lines of two polarities are reduced. In addition, in addition to matching the current transmission, the through hole 111 also affects the plastic deformation and bonding performance of the insulating layer. If the size of the through hole is too large, it will also reduce the bonding performance of the insulating layer. At the same time, it is necessary to increase the amount of insulating parts used for insulation, thereby increasing the cost. In the present application, the size of the through hole 111 is not too large, and the good mechanical properties and bonding properties of the insulating layer are maintained.

[0098] Optionally, in the portion of the insulating layer 11 corresponding to a back contact cell 2, along the first direction L1, the number of through holes 111 is less than or equal to the total number of columns of busbar lines in a back contact cell, and greater than or equal to half of the total number of columns of busbar lines in a back contact cell 2, the polarity of a column of busbar lines is the same, and the direction of the busbar line column is parallel to the second direction L2. Specifically, when the busbar lines are unevenly distributed or the number is too large, in order to reduce the number of through holes (the purpose is to increase production capacity), the through holes can be appropriately merged in the case of matching with the insulating member, for example, Figure 4 In the method, 10 through holes can be merged into 9 through holes, for example, the 1st and 2nd through holes on the far left can be merged into 1 through hole, so as to improve production capacity without using too many insulating parts. In addition, although appropriately reducing the number of through holes can improve the production efficiency of the insulating layer, this will double the hollow area and increase the coverage area of ​​the insulating parts, resulting in material waste and bringing about process difficulty. Therefore, in the portion of the insulating layer 11 corresponding to a back-contact battery cell 2, the number of through holes 111 along the first direction is less than or equal to the total number of columns of busbar lines in a back-contact battery cell, and greater than or equal to half of the total number of columns of busbar lines in a back-contact battery cell 2, which is the result of a good balance among the production efficiency of the insulating layer, the material cost of the insulating parts, and the process difficulty.

[0099] For example, if Figure 4 and Figure 3 The back contact cell shown corresponds to, Figure 4 In the example, 10 through holes can be merged into 9 through holes. For example, the first and second through holes on the far left can be merged into one through hole. Then, Figure 3 The first column of busbar lines from left to right and the second column of busbar lines can be combined in one through hole. For the leftmost column of busbar lines, the busbar line column and the first collector grid line and the second collector grid line with the same polarity as the busbar line column are electrically connected to the conductive layer for current conduction, and the first collector grid line and the second collector grid line with different polarity from the busbar line column are both provided with insulating members, and are both insulated from the conductive layer by the insulating members. Here, the insulating member can extend rightward to the position where the second busbar line column from left to right is electrically connected to the conductive layer to fully avoid short circuit. For the second busbar line column from left to right, the busbar line column and the first collector grid line and the second collector grid line with the same polarity as the busbar line column are both electrically connected to the conductive layer for current conduction, and the first collector grid line and the second collector grid line with different polarity from the busbar line column are both provided with insulating members, and are both insulated from the conductive layer by the insulating members.

[0100] Optional, see Figure 2 , Figure 3 , Figure 7 , Fig. 9 and Fig.12, the back contact cell also includes: a plurality of second electrical connection parts 26, which are electrically connected to the busbar line 23. Here, the second electrical connection parts 26 can be directly arranged on the busbar line 23 to achieve electrical connection, or in the first direction L1, there can be a certain distance between the second electrical connection parts 26 and the busbar line 23, and the electrical connection between the two is achieved by setting a connecting section between the two. The present invention does not make any specific restrictions on this. For example, the busbar line is located at the edge of the back contact cell in the second direction, and the second electrical connection part 26 can be appropriately moved inward. The second electrical connection part 26 can be a thickened section of the busbar line 23 itself, or a separately arranged electrical connection part. When the second electrical connection part 26 is a thickened section of the busbar line 23 itself, the line width of the rest of the busbar line 23 is smaller than the line width of the second electrical connection part 26. The second electrical connection part 26 is located in the through hole 111 to achieve better current collection and conduction. In the second direction L2, the second electrical connection portion 26 located in the same through hole 111 is spaced greater than or equal to 0.1 mm from the adjacent insulating member 5. On the one hand, a larger operating space is reserved for the setting of the insulating member, which facilitates the setting of the insulating member. On the other hand, the risk of short circuit can be further reduced.

[0101] For example, in the second direction L2, the spacing between the second electrical connection portion 26 located in the same through hole 111 and the adjacent insulating member 5 may be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, or 0.5 mm.

[0102] The widths of a through hole 111 at various positions may be equal or unequal. For a through hole with equal widths at various positions, its minimum width is its own width. For a through hole with unequal widths at some positions, its minimum width is the minimum size of the through hole in the first direction L1. Here, the second electrical connection portion 26 is located in the through hole 111, and the minimum width of the through hole 111 is greater than the maximum length of the second electrical connection portion 26 in the through hole 111. The direction in which the length of the second electrical connection portion 26 is located is parallel to the first direction L1. The second electrical connection portion 26 is covered in the through hole 111 as much as possible to improve the current collection effect.

[0103] Optional, see Figure 2 , Figure 3 , Figure 7 , Fig. 9 and Fig.12 The plurality of second electrical connection portions 26 include: an edge second electrical connection portion close to the edge of the back contact battery cell 2 in the second direction L2, for example, Figure 7The second electrical connection part 26 at the top is the edge second electrical connection part. In the second direction L2, the through hole 111 extends to the outside of the corresponding area of ​​the edge second electrical connection part, and on the side close to the edge of the back contact battery cell 2, the distance between the through hole 111 and the edge second electrical connection part is greater than or equal to 0.3 mm. In the case of compatible alignment error, it can be ensured that the edge second electrical connection part is located in the through hole, thereby improving the current collection effect.

[0104] For example, in the second direction L2, the through hole 111 extends to the outside of the area corresponding to the second electrical connection part of the edge, and on the side close to the edge of the back contact battery cell 2, the distance between the through hole 111 and the second electrical connection part of the edge can be 0.3mm, 0.4mm, 0.35mm, 0.33mm, 0.39mm, 0.42mm, 0.45mm, 0.48mm, or 0.5mm.

[0105] It should be noted that the back-contact cell may also have a middle second electrical connection portion located on the inner side of the edge second electrical connection portion. The size of the edge second electrical connection portion may be larger than the size of the middle second electrical connection portion or the same as the size of the middle second electrical connection portion. Specifically, the range of current collected by the edge second electrical connection portion may generally be larger than the range of current collected by the middle second electrical connection portion, that is, the current passing through the edge second electrical connection portion may generally be larger than the current passing through the middle second electrical connection portion. Therefore, the size of the edge second electrical connection portion is larger to match the lower resistance loss when it bears a larger regional current.

[0106] It should be noted that the width of the second electrical connection portion may be greater than the width of the first electrical connection portion on the collector grid line, and the width of the second electrical connection portion and the width of the first electrical connection portion are both parallel to the second direction L2. Specifically, the current collection range of the second electrical connection portion may be greater than the current collection range of the first electrical connection portion, that is, the current passing through the second electrical connection portion may usually be greater than the current passing through the first electrical connection portion, so the width of the second electrical connection portion is larger to match the resistance and low loss when it bears a larger area current. In addition, the number of first electrical connections is large, and the amount of electrode slurry can be reduced by reducing its width.

[0107] Optionally, the ratio of the width of the through hole 111 to the length of the second electrical connection portion 26 is (1.1 to 10): 1. The direction of the length of the second electrical connection portion 26 is parallel to the first direction L1. On the one hand, while being compatible with the alignment error, it can still be ensured that the second electrical connection portion 26 is covered in the through hole 111 as much as possible to improve the current collection effect. On the other hand, the width of the through hole 111 is not too large to avoid problems such as decreased adhesion due to the excessive size of the through hole 111. Because an oversized through hole 111 will reduce the bonding area between the insulating layer and the back contact battery cell, it will also weaken the overall strength of the insulating layer 11 and cause its plastic deformation. Plastic deformation may also cause the insulation of the insulating layer to decrease, causing the risk of short circuit, and at the same time increase the difficulty of the process.

[0108] For example, the ratio of the width of the through hole 111 to the length of the second electrical connection portion 26 can be 1.1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 7:1, 8:1, 9:1, or 10:1.

[0109] Furthermore, the ratio of the width of the through hole 111 to the length of the second electrical connection portion 26 in the through hole is (1.1 to 5): 1. The direction of the length of the second electrical connection portion 26 is parallel to the first direction L1. On the one hand, while being compatible with the alignment error, it can still be ensured that the second electrical connection portion 26 is covered in the through hole 111 as much as possible to improve the current collection effect. On the other hand, the width of the through hole 111 is smaller to avoid problems such as decreased adhesion due to the excessive size of the through hole 111. Because an oversized through hole 111 will reduce the bonding area between the insulating layer and the back contact cell, it will also weaken the overall strength of the insulating layer 11 and cause its plastic deformation. Plastic deformation may also cause the insulation of the insulating layer to decrease, causing the risk of short circuit, and at the same time increase the difficulty of the process.

[0110] For example, the ratio of the width of the through hole 111 to the length of the second electrical connection portion 26 in the through hole can be 1.1:1, 1.5:1, 2:1, 2.3:1, 2.5:1, 1.9:1, 3.3:1, 3.7:1, 4.3:1, 4.8:1, or 5:1.

[0111] Optionally, the second electrical connection portion 26 includes: a second surface close to the conductive layer, and within a through hole 111, the total area of ​​all second surfaces accounts for less than or equal to 20% of the area of ​​the through hole 111. Specifically, the area of ​​the through hole 111 needs to match the current transmission, and also affects the plastic deformation and bonding performance of the insulating layer 11. If the area of ​​the through hole is too large, the bonding performance of the insulating layer will be reduced, and the amount of insulating parts used needs to be increased for insulation, thereby increasing the cost. The size of the second surface of the second electrical connection portion 26 affects the amount of bonding material thereon. In the present application, within a through hole, the total area of ​​the second surfaces of all second electrical connection portions accounts for less than or equal to 20% of the area of ​​the through hole, which can not only ensure the effective transmission of current, but also effectively reduce the amount of insulating parts used and reduce the difficulty of the process.

[0112] For example, in a through hole, the total area of ​​all second surfaces may account for 20%, 18%, 14%, 13%, 10%, 8%, 5%, 3%, 2%, 1%, 0.5%, 0.1%, or 0.01% of the area of ​​the through hole 111 .

[0113] The present application does not specifically limit the shape of the second electrical connection portion 26. For example, the second surface may be square, rectangular, etc., and its size may be close to 1mm×1mm, etc., which can meet the requirements of gripping point positioning in the back contact cell sheet, can omit the positioning points inside the back contact cell sheet, can cancel the positioning points inside the back contact cell sheet, and can reduce the dead zone of the back contact cell sheet. The size of the back contact cell sheet in one direction may be between 160mm and 230mm, etc., and this is not specifically limited.

[0114] Optionally, the bonding material 112 is disposed on the second surface of the second electrical connection portion 26 close to the conductive layer, and the bonding material 112 can be disposed on the second surface of the second electrical connection portion 26 close to the conductive layer by printing, dispensing, etc. The orthographic projection of the bonding material 112 on the second surface and its extended surface is the second 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 second orthographic projection is located within the second surface, that is, the bonding material does not exceed the second surface of the second electrical connection portion, which can minimize the risk of short circuit caused by the offset of the bonding material. Specifically, once the bonding material exceeds the second electrical connection, the risk of short circuit will increase. The portion of the bonding material that exceeds the second electrical connection will reduce the distance from the opposite-sex grid line, increasing the risk of contact with the opposite-sex grid line and causing a short circuit. At the same time, the portion that exceeds will directly contact the silicon substrate. This portion 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 second electrical connection 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 the best for the area of ​​the second surface close to the second electrical connection, so as to ensure that the bonding material and the second electrical connection can have the largest contact area to provide the lowest contact loss.

[0115] 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 rectangle with chamfers 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. The extended surface of the second surface mentioned in the present application refers to a surface that is substantially coplanar or completely coplanar with the second surface, but larger than the second surface.

[0116] Optionally, the bonding material 112 is disposed on the second surface of the second electrical connection portion 26 close to the conductive layer. The orthographic projection of the bonding material 112 on the second surface and its extended surface is the second orthographic projection, and the area of ​​the second 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.

[0117] Optional, see Fig.13 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.

[0118] 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.

[0119] 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.

[0120] 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: An insulating member, a conductive back plate, and a back contact battery sheet disposed on the conductive back plate; The back contact cell comprises: a plurality of collector grid lines extending along a first direction; the collector grid lines of different polarities are spaced and alternately distributed along a second direction; a junction and a non-junction portion extending along the second direction and alternately distributed along the first direction, the junction and the non-junction portion both comprising a portion of the collector grid lines; the first direction is different from the second direction; 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 at least one of the bonding parts; the through hole is filled with a bonding material; a collector grid line of one polarity in the bonding part is electrically connected to the conductive layer through the bonding material, and a collector grid line of another polarity is provided with the insulating member and is insulated from the conductive layer by the insulating member; For one of the through holes, a ratio of a width of the insulating member to a width of the through hole is greater than 1 and less than or equal to 50; and a direction of the width is parallel to the first direction.

2. The photovoltaic module according to claim 1, characterized in that: For one of the through holes, a ratio of a width of the insulating member to a width of the through hole is greater than 1 and less than or equal to 25.

3. The photovoltaic module according to claim 1, characterized in that: For one of the through holes, at two opposite ends in the first direction, the insulating member extends beyond the through hole by at least 0.2 mm.

4. The photovoltaic module according to claim 1, characterized in that: For one of the through holes, the ratio of the total length of the insulating member to the length of the through hole is 15% to 75%; and the direction of the length is parallel to the second direction.

5. The photovoltaic module according to claim 1, characterized in that: For one of the through holes, a ratio of the total area of ​​the insulating members to the area of ​​the through hole is greater than or equal to 12%.

6. The photovoltaic module according to claim 1, characterized in that: In a portion of the insulating layer corresponding to one of the back contact solar cells, the number of the through holes is 9 to 28.

7. The photovoltaic module according to claim 1, characterized in that: A first electrical connection portion is provided on the collector grid line in the combining portion that is electrically connected to the conductive layer, and the first electrical connection portion is located in the through hole.

8. The photovoltaic module according to claim 7, characterized in that: In the second direction, a distance between the first electrical connection portion located in the same through hole and the adjacent insulating member is greater than or equal to 0.1 mm.

9. The photovoltaic module according to claim 7, characterized in that: The first electrical connection portion includes: a first surface close to the conductive layer, and the total area of ​​all the first surfaces in one through hole accounts for less than or equal to 20% of the area of ​​the through hole.

10. The photovoltaic module according to claim 7, characterized in that: The first electrical connection portion includes: a first surface close to the conductive layer, the bonding material is arranged on the first surface; the orthographic projection of the bonding material on the first surface and its extended surface is a first orthographic projection, and the first orthographic projection is located within the first surface.

11. The photovoltaic module according to claim 7, characterized in that: The first electrical connection portion includes: a first surface close to the conductive layer, the bonding material is arranged on the first surface; the orthographic projection of the bonding material on the first surface and its extended surface is a first orthographic projection, and the area of ​​the first orthographic projection is less than or equal to the area of ​​the first surface.

12. The photovoltaic module according to claim 7, characterized in that: The ratio of the width of the through hole to the length of the first electrical connection portion in the through hole is (1.1 to 10):1; the direction of the length of the first electrical connection portion is parallel to the first direction.

13. The photovoltaic module according to any one of claims 1 to 12, characterized in that: The collector grid lines include: a first collector grid line continuously arranged from one end of the back contact cell sheet to the other end thereof along the first direction.

14. The photovoltaic module according to claim 1, characterized in that: The back contact cell further comprises: a plurality of busbar lines extending along the second direction; busbar lines of different polarities are alternately and spaced apart along the first direction; the collector grid lines comprise: a second collector grid line electrically connected to the busbar line of the same polarity; the busbar line extends to a position where the second collector grid line is arranged; In the second direction, the through hole extends to the area corresponding to the bus grid line; the bus grid line in the through hole and the second bus grid line with the same polarity as the bus grid line are electrically connected to the conductive layer through the bonding material, and the second bus grid line with a different polarity from the bus grid line is provided with the insulating member and is insulated from the conductive layer by the insulating member.

15. The photovoltaic module according to claim 14, characterized in that: In the second direction, the plurality of collector grid lines are divided into at least two collector grid line groups by the bus grid line; One of the through holes only covers one of the collector grid lines and extends to a region corresponding to the bus grid lines adjacent to the collector grid line group.

16. The photovoltaic module according to claim 14, characterized in that: In the first direction, the insulating member at most extends to a position corresponding to a midline of an adjacent busbar line; and / or, In the first direction, the through hole at most extends to a position corresponding to a center line of an adjacent bus bar line.

17. The photovoltaic module according to claim 14, characterized in that: In a portion of the insulating layer corresponding to one of the back-contact cell sheets, the number of the through holes along the first direction is less than or equal to the total number of columns of busbar lines in one of the back-contact cell sheets, and greater than or equal to half of the total number of columns of busbar lines in one of the back-contact cell sheets.

18. The photovoltaic module according to claim 14, characterized in that: The back contact cell further comprises: a plurality of second electrical connection portions electrically connected to the busbar lines and located in the through holes; In the second direction, a distance between the second electrical connection portion located in the same through hole and the adjacent insulating member is greater than or equal to 0.1 mm.

19. The photovoltaic module according to claim 18, characterized in that: The plurality of second electrical connection portions include: an edge second electrical connection portion close to an edge of the back contact cell in the second direction; In the second direction, the through hole extends to the outside of the area corresponding to the edge second electrical connection portion; on the side close to the edge of the back contact battery cell, the distance between the through hole and the edge second electrical connection portion is greater than or equal to 0.3 mm.

20. The photovoltaic module according to claim 18, characterized in that: The ratio of the width of the through hole to the length of the second electrical connection portion in the through hole is (1.1 to 10):1; the direction of the length of the second electrical connection portion is parallel to the first direction.

21. The photovoltaic module according to claim 18, characterized in that: The second electrical connection portion includes: a second surface close to the conductive layer, the bonding material is arranged on the second surface; the orthographic projection of the bonding material on the second surface and the extended surface thereof is a second orthographic projection; The second orthographic projection is located within the second surface; and / or, An area of ​​the second orthographic projection is less than or equal to an area of ​​the second surface.

22. A photovoltaic system, characterized in that: include: A photovoltaic module as claimed in any one of claims 1 to 21.

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