Main-grid-free back contact battery, battery assembly and photovoltaic system

Abstract

The invention is suitable for the technical field of main-grid-free back contact batteries, and provides a main-grid-free back contact battery, a battery assembly and a photovoltaic system. The main-grid-free back contact battery comprises a cutting area and a plurality of grid line areas, the cutting area is located between two grid line areas, each grid line area comprises a middle area and a first edge area, the first edge area is located on the side, away from the cutting area, of the main-grid-free back contact battery, and a fine grid of the middle area is provided with a plurality of first connecting structures; the fine grid of the first edge region is provided with a plurality of second connecting structures, and the area of the second connecting structures is larger than that of the first connecting structures. By increasing the area of the second connecting structure in the first edge area, the area of the second connecting structure close to the cutting area is larger than the area of the first connecting structure away from the cutting area, and the effect that the pulling force of the cutting area on the welding strip is increased so as to reduce poor connection of the welding strip is achieved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a main grid-free back contact battery, a battery assembly and a photovoltaic system. Background Art

[0002] The busbar-free back-contact cell is a device that converts sunlight into electrical energy using the photoelectric effect. It is mainly made of photovoltaic materials (such as silicon) and excites electrons by absorbing photons to form an electric current. The cell includes a front electrode, a photovoltaic layer, and a back electrode, which can generate electricity under sunlight and is widely used in power generation systems and various electronic devices.

[0003] In the prior art, since a whole battery usually needs to be cut into half layers, a cutting area is left in the middle of the whole battery. In the cutting area, grid lines are usually not provided for the convenience of cutting. Therefore, the pulling force on the welding strip in this part is insufficient, which can easily cause poor connection. Summary of the invention

[0004] The present invention provides a busbar-free back contact battery, battery assembly and photovoltaic system to solve the technical problem of poor connection in the prior art. The embodiment of the present invention is implemented as follows: the present invention provides a busbar-free back contact battery, battery assembly and photovoltaic system.

[0005] The busbar-free back-contact battery includes: a silicon substrate and a plurality of fine grids arranged on the silicon substrate; the plurality of fine grids are arranged at intervals along a first direction and extend along a second direction, and the first direction intersects with the second direction; the busbar-free back-contact battery includes a cutting area and a plurality of grid line areas, and the cutting area is located between two grid line areas; the grid line area includes a middle area and a first edge area, and the first edge area is located close to the side of the busbar-free back-contact battery away from the cutting area, the fine grids in the middle area are provided with a plurality of first connection structures, and the fine grids in the first edge area are provided with a plurality of second connection structures, and the area of ​​the second connection structure is larger than the area of ​​the first connection structure.

[0006] Furthermore, the gate line area also includes a second edge area, which is located on the side of the main grid-free back contact battery away from the cutting area, and the fine grid in the second edge area is provided with a plurality of third connection structures, and the area of ​​the third connection structure is larger than that of the first connection structure.

[0007] Furthermore, there are multiple second connection structures, and the areas of the second connection structures are equal along the second direction; and / or there are multiple third connection structures, and the areas of the third connection structures are equal along the second direction.

[0008] Furthermore, there are multiple second connection structures, and along the first direction, the area of ​​the second connection structure increases or gradually decreases; and / or, there are multiple third connection structures, and along the first direction, the area of ​​the third connection structure gradually increases or gradually decreases.

[0009] Furthermore, there are multiple first connection structures, and areas of the first connection structures are equal along the first direction and / or the second direction.

[0010] Furthermore, along the first direction, the length of the busbar-free back contact cell is equal to 24 times the total length of a plurality of the second connection structures or a plurality of the third connection structures.

[0011] Furthermore, the area range of the second connection structure and / or the third connection structure is 46000 μm 2 Up to 190000μm 2 .

[0012] Furthermore, the length of the second connection structure and / or the third connection structure is greater than the length of the first connection structure.

[0013] Furthermore, the width of the second connection structure and / or the third connection structure is in a range of 95 μm to 105 μm.

[0014] Furthermore, the second connection structure and / or the third connection structure has a length ranging from 500 μm to 1800 μm.

[0015] Furthermore, the length of the first connection structure ranges from 500 μm to 700 μm.

[0016] Furthermore, the second connection structure and / or the third connection structure is made of non-burn-through slurry.

[0017] Furthermore, the second connection structure and / or the third connection structure is made of burn-through slurry.

[0018] Furthermore, it also includes a third edge area, which is located between the first edge area and the cutting area; the third edge area is provided with a plurality of first conductive structures, and the plurality of first conductive structures are arranged at intervals along the second direction and extend along the first direction, and the first conductive structures are located on the side of the fine gate facing the silicon substrate.

[0019] Furthermore, it also includes a fourth edge region, the second edge region is located between the fourth edge region and the middle region; the fourth edge region is provided with a plurality of second conductive structures, the plurality of second conductive structures are arranged at intervals along the second direction and extend along the first direction, and the second conductive structure is located on the side of the fine gate facing the silicon substrate.

[0020] An embodiment of the present invention further provides a battery assembly, which includes the busbar-free back contact battery as described above.

[0021] An embodiment of the present invention further provides a photovoltaic system, which includes the battery assembly as described above.

[0022] The embodiment of the present invention provides a busbar-free back contact cell, cell assembly and photovoltaic system. Since the first edge region is located on one side of the middle region close to the cutting region, the first edge region is arranged on both sides of the cutting region, and thus the area of ​​the second connection structure in the first edge region is increased so that the area of ​​the second connection structure close to the cutting region is larger than the area of ​​the first connection structure far from the cutting region, that is, the contact area between the second connection structure near the cutting region and the welding strip is increased, so as to increase the pulling force of the cutting region on the welding strip, so as to reduce the effect of poor welding strip connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 is a schematic diagram of a module of a photovoltaic system provided by an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of a module of a battery assembly provided by an embodiment of the present invention;

[0026] Figure 3 A schematic structural diagram of a busbar-free back contact battery provided by an embodiment of the present invention;

[0027] Figure 4 for Figure 3 A schematic structural diagram of a main-grid-free back-contact battery described in the embodiment of the present invention when a first conductive structure and a second conductive structure are provided.

[0028] Explanation of main component symbols: 1000, photovoltaic system; 1001, battery module; 100, main grid-free back contact battery; 10, silicon substrate; 20, fine grid; 30, first conductive structure; 40, second conductive structure; 21, first connection structure; 22, second connection structure; 23, third connection structure; 110, cutting area; 120, grid line area; 121, middle area; 122, first edge area; 123, second edge area; 124, third edge area; 125, fourth edge area. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "top", "bottom", "lateral", "longitudinal" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use scenarios of other materials.

[0035] See also Figure 1 and Figure 2 , the photovoltaic system 1000 in the embodiment of the present invention may include the battery assembly 1001 in the embodiment of the present invention, the battery assembly 1001 in the embodiment of the present invention may include a plurality of battery strings, and the battery string may include a plurality of busbar-free back-contact batteries 100 in the embodiment of the present invention. In the present invention, a plurality of busbar-free back-contact batteries 100 in the battery assembly 1001 may be connected in series in sequence through welding strips to form a battery string. The battery strings in the battery assembly 1001 may be connected in series, in parallel, or in series-parallel combination to realize the bus output of current. For example, the connection between the battery strings may be realized through a bus bar. The busbar-free back-contact battery 100 of the present invention may specifically be a back-contact battery.

[0036] The busbar-free back contact cell 100 can be a whole cell, or a half cell, a third cell, or a cell of other proportions divided from a whole cell. It should be noted that the drawings provided in this application are schematic diagrams, and some elements are not shown in the drawings. The purpose is to clearly describe the technical solution and highlight the key points of the invention. It is not intended to limit the technical solution to not include these unshown elements. For example, Figure 3 , Figure 4Only part of the electrodes (e.g., the fine grid 20, the first conductive structure 30, the second conductive structure 40, etc.) are shown, and not all of the electrodes are shown. In fact, the electrodes may include more parts. In other words, the drawings are only examples and do not limit the specific form of the busbar-free back contact battery 100.

[0037] Furthermore, the silicon substrate includes a front side and a back side, the front side faces the sun and mainly receives direct sunlight, and the back side faces the mounting surface of the battery assembly 1001 and mainly receives sunlight reflected by the mounting surface, and the mounting surface is, for example, the ground, a roof, etc. In other words, the back side is the side where the main grid back contact battery 100 is provided with a grid line. In addition, the silicon substrate is provided with a doping layer and a passivation layer arranged in a stacked manner, and the doping layer can be connected to the grid line to establish an ohmic contact.

[0038] A plurality of fine gates 20 are arranged on the back of the silicon substrate. The plurality of fine gates 20 are arranged in a first direction and extend in a second direction. The second direction intersects the first direction. The plurality of fine gates 20 specifically include positive fine gates 20 and negative fine gates 20. The first direction may specifically be the width direction of the fine gates 20, i.e. Figure 3 and Figure 4 The second direction may be specifically the length direction of the fine grid 20, that is, Figure 3 and Figure 4 Of course, in other embodiments, the first direction and the second direction may also be other directions, such as diagonal directions, etc., which are not specifically limited here. The plurality of fine grids 20 may be positive fine grids 20 or negative fine grids 20, which are not specifically limited here.

[0039] The busbar-free back contact cell 100 specifically includes a cutting area 110 and a plurality of grid line areas 120, wherein the cutting area 110 is located between two grid line areas 120. The cutting area 110 refers to a position reserved for cutting and slicing in the busbar-free back contact cell 100, and the busbar-free back contact cell 100 can be cut into multiple pieces from the cutting area 110. That is, the busbar-free back contact cell 100 can be cut along the cutting area 110 to divide the busbar-free back contact cell 100 into multiple busbar-free back contact cells 100.

[0040] The cutting area 110 is located between the two gate line areas 120, that is, the cutting area 110 can separate the two gate line areas 120, and a plurality of fine gates 20 are arranged in the gate line area 120. The gate line area 120 includes a middle area 121 and a first edge area 122, the first edge area 122 is located on the side of the middle area 121 close to the cutting area 110, the fine gates 20 in the middle area 121 are provided with a plurality of first connection structures 21, and the fine gates 20 in the first edge area 122 are provided with a plurality of second connection structures 22, and the area of ​​the second connection structure 22 is larger than the area of ​​the first connection structure 21. Therefore, a plurality of second connection structures 22 are arranged on both sides of the cutting area 110.

[0041] Specifically, the first edge region 122 is located on one side of the middle region 121 close to the cutting region 110, and the cutting region 110 is located between the two gate line regions 120, that is, the first edge region 122 is provided on both sides of the cutting region 110. The fine grid 20 of the middle region 121 is provided with a plurality of first connection structures 21, and the fine grid 20 of the first edge region 122 is provided with a plurality of second connection structures 22. The fine grid 20 of the middle region 121 is connected to the welding strip through the first connection structure 21, and the fine grid 20 of the first edge region 122 is connected to the welding strip through the second connection structure 22. The connection method of the welding strip can be specifically connected by welding or dispensing. The area of ​​the second connection structure 22 is larger than the area of ​​the first connection structure 21, and the widths of the first connection structure 21 and the second connection structure 22 are both larger than the fine grid 20, that is, the first connection structure 21 and the second connection structure 22 are both arranged to be thicker than the fine grid 20.

[0042] Each first connection structure 21 and each second connection structure 22 are specifically arranged on the fine grid 20 at intervals, and the first connection structure 21 and the second connection structure 22 can be specifically composed of multiple welding points (also called pad points); or the first connection structure 21 and the second connection structure 22 can be specifically composed of multiple welding points or a larger welding point. Optionally, the outer contour of each first connection structure 21 and the second connection structure 22 can be set to a trapezoid, a circle, a rectangle or an octagon, etc.

[0043] Because a position for cutting the busbar-free back contact battery 100 needs to be reserved in the cutting area 110, no grid line is set in the cutting area 110. Therefore, when setting a welding strip in the busbar-free back contact battery 100, there is no fine grid 20 grid line set in the cutting area 110 to provide tension to the welding strip. Compared with the welding strip located in the grid line area 120, the tension of the portion of the welding strip located in the cutting area 110 is insufficient, and poor connection is likely to occur.

[0044] Therefore, in the present invention, because the first edge area 122 is located on one side of the middle area 121 close to the cutting area 110, the first edge area 122 is set on both sides of the cutting area 110, so by increasing the area of ​​the second connection structure 22 in the first edge area 122, the area of ​​the second connection structure 22 close to the cutting area 110 is larger than the area of ​​the first connection structure 21 far from the cutting area 110, that is, the contact area between the second connection structure 22 near the cutting area 110 and the welding strip is increased, so as to increase the pulling force of the cutting area 110 on the welding strip to reduce the poor connection of the welding strip. And as for the number of the first connection structure 21 and the second connection structure 22, the first connection structure 21 can be set to one or more, and the second connection structure 22 can be set to one or more.

[0045] Furthermore, in the maingate-free back contact battery 100, in addition to the first edge area 122, in a possible embodiment, the gate line area 120 also includes a second edge area 123, and the second edge area 123 is located on the other side of the middle area 121 close to the cutting area 110. The second edge area 123 is provided with a plurality of third connection structures 23, and the area of ​​the third connection structure 23 is greater than the area of ​​the first connection structure 21.

[0046] Specifically, the gate line region 120 further includes a second edge region 123, the first edge region 122 and the second edge region 123 are arranged opposite to each other, and the second edge region 123 is located on the other side of the middle region 121 close to the cutting region 110, that is, the second edge region 123 is located on the side of the middle region 121 away from the cutting region 110. The second edge region 123 may be an edge region of the busbar-free back contact battery 100, and of course in other embodiments, the second edge region 123 may also be a gate line region close to the cutting region.

[0047] In the present invention, the fine grid 20 of the second edge region 123 is provided with a plurality of third connection structures 23, and the fine grid 20 of the second edge region 123 is connected to the welding strip through the third connection structure 23, and the connection method of the welding strip can be specifically connected by welding or dispensing. The area of ​​the third connection structure 23 is also set to be larger than the area of ​​the first connection structure 21. In addition, the width of the third connection structure 23 is larger than the fine grid 20, that is, the third connection structure 23 is set to be thicker than the fine grid 20.

[0048] Each third connection structure 23 is specifically arranged on the fine grid 20 at intervals, and the third connection structure 23 can be specifically composed of multiple welding points (also called pad points); or, the third connection structure 23 can be specifically composed of multiple welding points or a larger welding point. Optionally, the outer contour of each third connection structure 23 can be set to be a trapezoid, a circle, a rectangle or an octagon, etc.

[0049] Because in the busbar-less back contact battery 100, the second edge region 123 is the edge portion of the busbar-less back contact battery 100, and because in the busbar-less back contact battery 100, the stress tension at the edge portion is more concentrated, so the tension of the welding ribbon in this portion is insufficient, which is prone to poor connection problems.

[0050] Therefore, in the present invention, the second edge region 123 is the edge portion of the busbar-free back contact battery 100, and thus by increasing the area of ​​the third connection structure 23 in the second edge region 123, that is, increasing the contact area between the third connection structure 23 in the second edge region 123 and the welding strip, the tension of the second edge region 123 on the welding strip is increased, so as to increase the connection tension between the welding strip and the fine grid 20 at the edge portion of the busbar-free back contact battery 100, so as to disperse and resist the stress and tension closer to the edge of the busbar-free back contact battery 100, so as to increase the tension of the welding strip at the edge portion, improve the firmness of the welding strip, stabilize the welding strip connection, and reduce the risk of poor welding strip connection. And for the third connection structure 23, the number of the third connection structure 23 can be set to one or more.

[0051] Furthermore, in a possible implementation, there are multiple first connection structures 21, and the areas of the second connection structures 22 are equal along the second direction; and / or there are multiple third connection structures 23, and the areas of the third connection structures 23 are equal along the second direction. That is, in the first edge region 122, there are multiple second connection structures 22, and the areas of the second connection structures 22 are the same along the length direction of the fine grid 20; in the second edge region 123, there are multiple third connection structures 23, and the areas of the third connection structures 23 are the same along the length direction of the fine grid 20.

[0052] Because, when the welding strip is set on the fine grid 20, the welding strip is set along the width direction of the fine grid 20, because for the tension of the mainbar-less back contact battery 100 on the welding strip, along the second direction, for the mainbar-less back contact battery 100, the tension of the mainbar-less back contact battery 100 on the welding strip is the same. Therefore, by setting the second connection structure 22 in the second direction of the mainbar-less back contact battery 100 to be equal in area, the tension of the welding strip can be evenly distributed, the risk of poor connection of the welding strip due to uneven tension can be reduced, and the stability of the welding strip connection can be improved. Similarly, by setting the third connection structure 23 in the second direction of the mainbar-less back contact battery 100 to be equal in area, the tension of the welding strip can be evenly distributed, the risk of poor connection of the welding strip due to uneven tension can be reduced, and the stability of the welding strip connection can be improved.

[0053] Furthermore, in a possible implementation, Figure 3 to Figure 4As shown, the number of the second connection structures 22 is multiple, and along the first direction, the area of the second connection structures 22 gradually increases or gradually decreases; and / or, the number of the third connection structures 23 is multiple, and along the first direction, the area of the third connection structures 23 gradually increases or gradually decreases.

[0054] In the main-gridless back-contact battery 100, since the stress and tension are relatively concentrated in the edge part, the tensile force of the solder ribbon connection in this part is insufficient, and it is easy to have problems with poor solder ribbon connection. Moreover, the closer to the edge of the main-gridless back-contact battery 100, the stronger the stress and tension, the more difficult it is for the solder ribbon to be stably connected, and the more likely it is to cause problems with poor connection. Therefore, for the first edge area 122, after the cutting area 110 is cut, the first edge area 122 becomes the edge part of a newly formed back-contact battery. Therefore, by setting the area of the second connection structures 22 to gradually increase or gradually decrease, that is, the closer to the edge of the main-gridless back-contact battery 100, the larger the area of the second connection structures 22 is set, so as to gradually increase the connection tensile force between the solder ribbon closer to the edge of the main-gridless back-contact battery 100 and the fine grid 20, to disperse and resist the gradually increasing stress and tension closer to the edge of the main-gridless back-contact battery 100, so as to achieve the effect of improving the tensile force of the solder ribbon in the edge part, improving the firmness of the solder ribbon connection, and reducing the risk of poor solder ribbon connection.

[0055] Specifically, there are multiple second connection structures 22 in the first edge area 122. Each of the second connection structures 22 is specifically arranged at intervals along the first direction. Along the first direction, the area of the second connection structures 22 gradually increases or gradually decreases. For the way of gradually increasing or gradually decreasing the area of the second connection structures 22, there can be various situations. For example, there are 6 first connection structures 21 along the first direction, and the areas of each of the second connection structures 22 are in turn: X1, X2, X3, X4, X5, X6. It can be X1 < X2 < X3 < X4 < X5 < X6 so that the area of the first connection structures 21 gradually increases, or it can also be the case of X1 = X2 < X3 = X4 < X5 = X6 so that the area of the first connection structures 21 gradually increases. There is no limit here. The case of gradually decreasing is similar and will not be elaborated here.

[0056] For the second edge region 123, the second edge region 123 is the edge portion of a back contact battery. Therefore, by setting the area of ​​the third connection structure 23 to gradually increase or gradually decrease, that is, the closer to the edge of the busbar-free back contact battery 100, the larger the area of ​​the third connection structure 23 is set, so as to gradually increase the connection tension between the welding strip and the fine grid 20 closer to the edge of the busbar-free back contact battery 100, so as to disperse and resist the stress and tension that gradually increase closer to the edge of the busbar-free back contact battery 100, so as to achieve the effect of increasing the tension of the welding strip at the edge, improving the firmness of the welding strip connection, and reducing the risk of poor welding strip connection.

[0057] Specifically, a plurality of third connection structures 23 are provided in the second edge region 123, and each third connection structure 23 is specifically arranged at intervals along the first direction, and the area of ​​the third connection structure 23 gradually increases or decreases along the first direction. For the manner in which the area of ​​the third connection structure 23 gradually increases or decreases, reference can be made to the second connection structure 22, and no further description will be given here.

[0058] Furthermore, regarding the area arrangement of the first connection structure 21, in a possible embodiment, the number of the first connection structures 21 is multiple, and the areas of the first connection structures 21 are equal along the first direction and / or the second direction. Specifically, in the busbar-free back contact battery 100, by setting the area of ​​the first connection structure 21 to be unchanged along the length direction of the fine grid 20 and / or along the width direction of the fine grid 20, a stable welding area is provided for the middle area 121 of the busbar-free back contact battery 100, ensuring that the welding part of the middle area 121 has uniform mechanical strength and stability, and also achieving the effect of optimizing the use of materials and reducing costs.

[0059] Moreover, in a possible implementation manner, the length of the first connection structure 21 ranges from 500 μm to 700 μm.

[0060] Specifically, when the length of the first connection structure 21 is too small, the accuracy requirement for positioning the first connection structure 21 is too high, that is, it is not easy to set welding materials or dispensing materials on the first connection structure 21, which increases the challenge and complexity of the welding strip connection process; and when the length of the first connection structure 21 is too long, it may also short-circuit adjacent welding strips, affecting the battery efficiency of the busbar-free back contact battery 100, causing damage to the busbar-free back contact battery 100, and also causing the problem of wasting costs. Therefore, by setting the length range of the first connection structure 21 to between 500μm and 700μm, it is possible to achieve the effect of reducing the complexity of the welding strip connection while ensuring the battery efficiency of the busbar-free back contact battery 100.

[0061] In such an embodiment, the length of the first connection structure 21 may be, for example, 550 μm, 600 μm, 610 μm, 620 μm, 630 μm, 640 μm, 650 μm, 700 μm, 750 μm, or any value within the range of 500 μm to 700 μm.

[0062] Further, regarding the area relationship between the first connection structure 21 and the second connection structure 22 , in a possible implementation, along the first direction, the length of the busbar-free back contact cell 100 is equal to 24 times the total length of the plurality of second connection structures 22 or the plurality of third connection structures 23 .

[0063] Specifically, for the busbar-free back contact cell 100, the portion of the middle area 121 is larger than the portion of the first edge area 122, so the area of ​​the first connection structure 21 in the middle area 121 needs to be larger than the area of ​​the second connection structure 22 in the first edge area 122 to meet the needs of the solder strip connection. By setting the length of the busbar-free back contact cell 100 equal to 24 times the total length of the plurality of second connection structures 22 or the plurality of third connection structures 23, more space is reserved in the middle area 121 with a larger area to set the first connection structure 21, so as to provide a more stable contact for the portion of the solder strip connected to the middle area 121, and further achieve the effect of reducing the problem of poor solder strip connection.

[0064] Optionally, for the area of ​​a single second connection structure 22 and the area of ​​a single third connection structure 23, in a possible implementation manner, the area range of the second connection structure 22 and / or the third connection structure 23 is 46000 μm 2 Up to 190000μm 2 The width of the second connection structure 22 and / or the third connection structure 23 is in the range of 95 μm to 105 μm; the length of the second connection structure 22 and / or the third connection structure 23 is in the range of 500 μm to 1800 μm.

[0065] Specifically, the area range of a single second connection structure 22 is set to 46000 μm 2 Up to 190000μm 2 The area range of a single third connection structure 23 is set at 46000μm 2 Up to 190000μm 2Because when the area of ​​the second connection structure 22 and / or the third connection structure 23 is too small, the contact area between the second connection structure 22 and / or the third connection structure 23 and the welding strip is insufficient, and the welding strip will have insufficient connection strength when connected, which is prone to poor welding strip connection; and when the area of ​​the second connection structure 22 and / or the third connection structure 23 is too large, the second connection structure 22 and / or the third connection structure 23 may be too large, resulting in a short circuit with the fine grid 20 adjacent to the second connection structure 22 and / or the third connection structure 23, affecting the battery efficiency of the main grid back contact-free battery 100, causing damage to the main grid back contact-free battery 100, and also causing a waste of cost. Therefore, by setting the area range of the second connection structure 22 and / or the third connection structure 23 to 46000μm 2 Up to 190000μm 2 In this way, the connection strength of the welding strip can be maintained while ensuring the battery efficiency of the main grid-free back contact battery 100.

[0066] In such an embodiment, the area of ​​the second connection structure 22 and / or the third connection structure 23 may be, for example, 60,000 μm. 2 、65000μm 2 、70000μm 2 、75000μm 2 、80000μm 2 、85000μm 2 , 90000μm 2 、95000μm 2 , 100000μm 2 、110000μm 2 , 120000μm 2 、130000μm 2 、140000μm 2 、150000μm 2 or 46000 μm 2 Up to 190000μm 2 Any value in the range.

[0067] Moreover, the width of a single second connection structure 22 and / or third connection structure 23 ranges from 95 μm to 105 μm. Because, when the width of the second connection structure 22 and / or the third connection structure 23 is too small, the accuracy requirement for positioning the second connection structure 22 and / or the third connection structure 23 is too high, that is, it is not easy to set welding materials or dispensing materials on the second connection structure 22 and / or the third connection structure 23, which increases the challenge and complexity in the welding strip connection process; and when the width of the second connection structure 22 and / or the third connection structure 23 is too wide, the adjacent fine grids 20 may also be short-circuited, affecting the battery efficiency of the busbar-free back contact battery 100, causing the problem of damage to the busbar-free back contact battery 100, and there will also be a problem of wasting costs. Therefore, by setting the width of the second connection structure 22 and / or the third connection structure 23 to range from 95 μm to 105 μm, it is possible to achieve the effect of keeping the complexity of the welding strip connection reduced while ensuring the battery efficiency of the busbar-free back contact battery 100. Preferably, the width of the second connection structure 22 and / or the third connection structure 23 may be set to 100 μm.

[0068] In addition, the length of a single second connection structure 22 and / or third connection structure 23 ranges from 500 μm to 1800 μm. Because, when the length of the second connection structure 22 and / or the third connection structure 23 is too small, the accuracy requirement for positioning the second connection structure 22 and / or the third connection structure 23 is too high, that is, it is not easy to set welding materials or dispensing materials on the second connection structure 22 and / or the third connection structure 23, which increases the challenge and complexity in the welding strip connection process; and when the length of the second connection structure 22 and / or the third connection structure 23 is too long, the adjacent welding strips may also be short-circuited, affecting the battery efficiency of the busbar-free back contact battery 100, causing the problem of damage to the busbar-free back contact battery 100, and there will also be a problem of wasting costs. Therefore, by setting the length of the second connection structure 22 and / or the third connection structure 23 to range from 500 μm to 1800 μm, it is possible to achieve the effect of keeping the complexity of the welding strip connection reduced while ensuring the battery efficiency of the busbar-free back contact battery 100.

[0069] In such an embodiment, the length of the second connecting structure 22 and / or the third connecting structure 23 may be, for example, 600μm, 650μm, 700μm, 750μm, 800μm, 850μm, 900μm, 950μm, 1000μm, 1100μm, 1200μm, 1300μm, 1400μm, 1500μm or any value in the range of 500μm to 1800μm.

[0070] Furthermore, in a possible implementation manner, the length of the second connection structure 22 and / or the third connection structure 23 is greater than the length of the first connection structure 21 .

[0071] Specifically, the first connection structure 21, the second connection structure 22, and the third connection structure 23 can all be set to be rectangular. And the widths of the first connection structure 21, the second connection structure 22, and the third connection structure are the same, but the lengths are different. By setting the length of the second connection structure 22 and / or the third connection structure 23 to be greater than the length of the first connection structure 21, it can be ensured that the area of ​​the second connection structure 22 and / or the third connection structure 23 is greater than the area of ​​the first connection structure 21.

[0072] Furthermore, regarding the material of the second connection structure 22 and / or the third connection structure 23, in a possible implementation manner, the second connection structure 22 and / or the third connection structure 23 is made of a non-burn-through slurry.

[0073] Specifically, the fine grid 20 is made of a burn-through slurry, while the second connection structure 22 in the fine grid 20 of the first edge region 122 is made of a non-burn-through slurry; and / or, the third connection structure 23 in the fine grid 20 of the second edge region 123 is made of a non-burn-through slurry. Because the non-burn-through slurry is generally more stable than the burn-through slurry, and the non-burn-through slurry will not penetrate the passivation layer of the battery, thereby reducing the potential damage to other layers of the busbar-free back contact battery 100. Therefore, by setting the second connection structure 22 and / or the third connection structure 23 to be made of a non-burn-through slurry, damage to the first edge region 122 and / or the fine grid 20 of the first edge region 122 can be avoided, and the non-burn-through slurry can also provide sufficient adhesion to the solder strip, thereby achieving the effect of improving the stability of the solder strip connection and the electrical performance of the busbar-free back contact battery 100.

[0074] Of course, for the material of the second connection structure 22 and / or the third connection structure 23, in addition to being made of non-burn-through slurry, in a possible implementation manner, the second connection structure 22 and / or the third connection structure 23 is made of burn-through slurry.

[0075] Specifically, the second connection structure 22 and / or the third connection structure 23 can also be made of a burn-through slurry. Because the burn-through slurry can penetrate the protective layer at high temperature and directly contact the doping material of the busbar-free back contact battery 100, thereby forming a stronger electrical connection, thereby achieving the effect of improving the efficiency of the busbar-free back contact battery 100. In addition, the fine grid 20 is made of a burn-through slurry, that is, the fine grid 20 of the first edge area 122 and the second connection structure 22 in the fine grid 20 are both made of a burn-through slurry, and / or, the fine grid 20 of the second edge area 123 and the third connection structure 23 in the fine grid 20 are both made of a burn-through slurry. During the preparation, the consistency of the slurry of the fine grid 20 and the second connection structure 22 and / or the slurry of the fine grid 20 and the third connection structure 23 can be maintained, thereby achieving the effect of reducing costs.

[0076] For further information, see Figure 4 The busbar-free back contact cell 100 of the present invention further includes a third edge region 124, and the first edge region 122 is located between the third edge region 124 and the cutting region 110; the third edge region 124 is provided with a plurality of first conductive structures 30, and the plurality of first conductive structures 30 are arranged at intervals along the second direction and extend along the first direction, and the first conductive structures 30 are located on the side of the fine gate 20 facing the silicon substrate 10. The first conductive structure 30 is specifically connected to the fine gate 20 of the same polarity in the third edge region 124. Along the first direction, the first conductive structure 30 is also connected to a second connecting structure 22 closest to the third edge region 124, and the first conductive structure 30 can be a positive electrode or a negative electrode.

[0077] Specifically, since the stress and tension at the edge of the main-grid-free back-contact battery 100 is relatively concentrated, the soldering ribbon may be at risk of being pulled off and cracked in this area. Therefore, a third edge area 124 is provided in the main-grid-free back-contact battery 100. The first edge area 122 is located between the third edge area 124 and the cutting area 110. That is, compared with the first edge area 122, the third edge area 124 is closer to the cutting area 110. The third edge area 124 is provided with a plurality of first conductive structures 30, and the first conductive structures 30 are located on the side of the fine gate 20 facing the silicon substrate 10. That is, in the third edge area 124, the fine gate 20 is located between the first conductive structure 30 and the silicon substrate 10. Optionally, the first conductive structure 30 can specifically be a main gate or other conductive structure.

[0078] In the third edge area 124, by setting the first conductive structure 30, the pulling force on the welding strip of the edge portion of the mainbar-less back contact battery 100 formed by cutting from the cutting area 110 can be shared, thereby reducing the risk of the welding strip set at the edge portion of the mainbar-less back contact battery 100 being pulled off and cracked, ensuring the connection stability between the welding strip and the mainbar-less back contact battery 100, and improving the performance of the mainbar-less back contact battery 100.

[0079] For further information, see Figure 4 The busbar-free back contact cell 100 of the present invention further includes a fourth edge region 125, which is located between the second edge region 123 and the middle region 121; the fourth edge region 125 is provided with a plurality of second conductive structures 40, which are arranged at intervals along the second direction and extend along the first direction, and the second conductive structures 40 are located on the side of the fine gate 20 facing the silicon substrate 10. The second conductive structures 40 are specifically connected to the fine gates 20 of the same polarity in the fourth edge region 125. Along the first direction, the second conductive structure 40 is also connected to a third connecting structure 23 closest to the fourth edge region 125, and the second conductive structure 40 can be a positive electrode or a negative electrode.

[0080] Specifically, since the stress and tension at the edge of the main-grid-free back-contact battery 100 is relatively concentrated, the soldering ribbon may be at risk of being pulled off and cracked in this area. Therefore, a fourth edge area 125 is provided in the main-grid-free back-contact battery 100. The first edge area 122 is located between the fourth edge area 125 and the middle area 121. That is, compared with the second edge area 123, the fourth edge area 125 is closer to the edge of the main-grid-free back-contact battery 100. The fourth edge area 125 is provided with a plurality of second conductive structures 40, and the second conductive structures 40 are located on the side of the fine grid 20 facing the silicon substrate 10. That is, in the fourth edge area 125, the fine grid 20 is located between the second conductive structure 40 and the silicon substrate 10. Optionally, the second conductive structure 40 can specifically be a main grid or other conductive structure.

[0081] In the fourth edge area 125, by setting the second conductive structure 40, the pulling force on the welding strip at the edge part of the mainbar-less back contact battery 100 can be shared, thereby reducing the risk of the welding strip set at the edge part of the mainbar-less back contact battery 100 being pulled off and cracked, ensuring the connection stability between the welding strip and the mainbar-less back contact battery 100, and improving the performance of the mainbar-less back contact battery 100.

[0082] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0083] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A busbar-free back contact battery, characterized in that: include: A silicon substrate and a plurality of fine gates disposed on the silicon substrate; the plurality of fine gates are arranged at intervals along a first direction and extend along a second direction, and the first direction intersects the second direction; The busbar-free back contact battery comprises a cutting area and a plurality of grid line areas, wherein the cutting area is located between two of the grid line areas; The gate line area includes a middle area and a first edge area, the first edge area is located close to the side of the main grid-free back contact battery away from the cutting area, the fine grid in the middle area is provided with a plurality of first connection structures, and the fine grid in the first edge area is provided with a plurality of second connection structures, and the area of ​​the second connection structure is larger than the area of ​​the first connection structure.

2. The busbar-free back contact cell according to claim 1, characterized in that: The grid line area also includes a second edge area, which is located on a side of the main grid-free back contact battery away from the cutting area. The fine grid in the second edge area is provided with a plurality of third connection structures, and the area of ​​the third connection structure is larger than that of the first connection structure.

3. The busbar-free back contact cell according to claim 2, characterized in that: There are multiple second connection structures, and the areas of the second connection structures are equal along the second direction; and / or there are multiple third connection structures, and the areas of the third connection structures are equal along the second direction.

4. The busbar-free back contact cell according to claim 2, characterized in that: There are multiple second connection structures, and along the first direction, the area of ​​the second connection structure increases or decreases gradually; and / or there are multiple third connection structures, and along the first direction, the area of ​​the third connection structure increases or decreases gradually.

5. The busbar-free back contact cell according to claim 1, characterized in that: There are multiple first connection structures, and areas of the first connection structures are equal along the first direction and / or the second direction.

6. The busbar-free back contact cell according to claim 2, characterized in that: Along the first direction, the length of the busbar-free back contact cell is equal to 24 times the total length of a plurality of the second connection structures or a plurality of the third connection structures.

7. The busbar-free back contact cell according to claim 2, characterized in that: The area range of the second connection structure and / or the third connection structure is 46000 μm 2 Up to 190000μm 2 .

8. The busbar-free back contact cell according to claim 2, characterized in that: The length of the second connection structure and / or the third connection structure is greater than the length of the first connection structure.

9. The busbar-free back contact cell according to claim 2, characterized in that: The second connection structure and / or the third connection structure has a width ranging from 95 μm to 105 μm.

10. The busbar-free back contact cell according to claim 2, characterized in that: The second connection structure and / or the third connection structure has a length ranging from 500 μm to 1800 μm.

11. The busbar-free back contact cell according to claim 1, characterized in that: The length of the first connection structure ranges from 500 μm to 700 μm.

12. The busbar-free back contact cell according to claim 2, characterized in that: The second connection structure and / or the third connection structure is made of non-burn-through slurry.

13. The busbar-free back contact cell according to claim 2, characterized in that: The second connection structure and / or the third connection structure is made of a burn-through slurry.

14. The busbar-free back contact cell according to claim 1, characterized in that: Also comprising a third edge region, the third edge region being located between the first edge region and the cutting region; The third edge region is provided with a plurality of first conductive structures, which are arranged at intervals along the second direction and extend along the first direction, and are located on a side of the fine gate facing the silicon substrate.

15. The busbar-free back contact cell according to claim 2, characterized in that: Also comprising a fourth edge region, wherein the second edge region is located between the fourth edge region and the middle region; The fourth edge region is provided with a plurality of second conductive structures, which are arranged at intervals along the second direction and extend along the first direction, and are located on a side of the fine gate facing the silicon substrate.

16. A battery assembly, characterized in that: The invention comprises a busbar-free back contact cell according to any one of claims 1 to 15.

17. A photovoltaic system, characterized in that: Comprising the battery assembly as claimed in claim 16.

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