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

Abstract

The utility model is suitable for the technical field of main-grid-free back contact cells, and provides a main-grid-free back contact cell, a cell 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 utility model relates to the technical field of photovoltaic, in particular to a main-grid-free back-contact battery, a battery module and a photovoltaic system. Background Art

[0002] The main-grid-free back-contact battery is a device that converts sunlight into electrical energy by using the photovoltaic effect. It is mainly made of photovoltaic materials (such as silicon), and electrons are excited by absorbing photons to form an electric current. The battery includes a front electrode, a photovoltaic layer and a back electrode, and can generate electricity under sunlight irradiation, 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-batteries, a cutting area will be left in the middle part of the whole battery. In the cutting area, grid lines are usually not provided for convenient cutting. Therefore, the pulling force of the soldering tape on this part is insufficient, which is likely to cause poor connection. Summary of the Utility Model

[0004] The utility model provides a main-grid-free back-contact battery, a battery module and a photovoltaic system to solve the technical problem of poor connection easily caused in the prior art. The embodiments of the utility model are implemented as follows. The utility model provides a main-grid-free back-contact battery, a battery module and a photovoltaic system.

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

[0006] Furthermore, the grid-line area further includes a second edge area, the second edge area is located on the side of the main-grid-free back-contact battery far from the cutting area, and a plurality of third connection structures are provided on the fine grids in the second edge area, and the area of the third connection structure is larger than the area of the first connection structure.

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

[0008] Furthermore, the number of the second connection structures is plural, and along the first direction, the area of the second connection structures increases or gradually decreases; and / or, the number of the third connection structures is plural, and along the first direction, the area of the third connection structures gradually increases or gradually decreases.

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

[0010] Furthermore, along the first direction, the length of the back-contact cell without main grid is equal to 24 times the total length of several of the second connection structures or several of the third connection structures.

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

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

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

[0014] Furthermore, the length range of the second connection structures and / or the third connection structures is 500 μm to 1800 μm.

[0015] Furthermore, the length range of the first connection structures is 500 μm to 700 μm.

[0016] Furthermore, the second connection structures and / or the third connection structures are made of non-burn-through paste.

[0017] Furthermore, the second connection structures and / or the third connection structures are made of burn-through paste.

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

[0019] Further, it further includes a fourth edge region, and the second edge region is located between the fourth edge region and the intermediate region; a plurality of second conductive structures are provided in the fourth edge region, and the plurality of second conductive structures are arranged at intervals along the second direction and all extend along the first direction, and the second conductive structures are located on the side of the fine grid facing the silicon substrate.

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

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

[0022] For a main-grid-free back-contact battery, a battery assembly, and a photovoltaic system provided by an embodiment of the present invention. Since the first edge region is located on the side of the intermediate region close to the cutting region, and the first edge regions are provided on both sides of the cutting region, by increasing the area of the second connection structure in the first edge region, the area of the second connection structure close to the cutting region is made 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 solder strip is increased, achieving the effect of increasing the pulling force of the cutting region on the solder strip to reduce the poor connection of the solder strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

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

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

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

[0027] Figure 4 is Figure 3 a structural schematic diagram of the main-grid-free back-contact battery described in [reference] when it is provided with a first conductive structure and a second conductive structure.

[0028] Description of main component symbols: 1000, photovoltaic system; 1001, battery module; 100, main-gridless 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 implementation manners

[0029] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present utility model, and should not be construed as a limitation to the present utility model. In addition, it should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0030] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model 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 thus should not be construed as a limitation to the present utility model.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "a plurality of" means two or more, unless otherwise specifically defined.

[0032] In the description of the present utility model, 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 may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a communication connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] In the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is less than that of the second feature.

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

[0035] Please refer to Figure 1 and Figure 2 , the photovoltaic system 1000 in the embodiment of the present utility model may include the battery module 1001 in the embodiment of the present utility model. The battery module 1001 in the embodiment of the present utility model may include a plurality of battery strings, and the battery string may include a plurality of main-gridless back-contact batteries 100 in the embodiment of the present utility model. In the present utility model, a plurality of main-gridless back-contact batteries 100 in the battery module 1001 may be sequentially connected in series through solder tapes to form a battery string. Each battery string in the battery module 1001 may be connected in series, in parallel, or in a series-parallel combination to achieve the current collection and output. For example, the connection between each battery string may be achieved through a bus bar. The main-gridless back-contact battery 100 of the present utility model may specifically be a back-contact battery.

[0036] The main-gridless back-contact battery 100 may be a whole battery cell, or may be a half cell, a one-third cell or other proportion of battery cells divided from a whole battery cell. It should be noted that the drawings provided in this application are schematic diagrams, and some elements are not shown in the figures. The purpose is to clearly describe the technical solution and highlight the key points of the utility model. It is not intended to limit the technical solution and does not include these elements not shown. For example, Figure 3 , Figure 4Only some electrodes are shown (e.g., the fine grid 20, the first conductive structure 30, the second conductive structure 40, etc.), and not all electrodes are shown. In fact, the electrodes may include more parts. That is to say, the drawings are only examples and do not represent a limitation on the specific form of the main-gridless back-contact cell 100.

[0037] Further, the silicon substrate includes a front side facing the back 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 module 1001 and mainly receives the sunlight reflected by the mounting surface. The mounting surface is, for example, the ground, the roof, etc. Or rather, the back side is the side of the main-gridless back-contact cell 100 where the grid lines are provided. And, the silicon substrate is provided with a doped layer and a passivation layer arranged in a stacked manner, and the doped layer can be connected to the grid lines to establish an ohmic contact.

[0038] A plurality of fine grids 20 are provided on the back side of the silicon substrate. The plurality of fine grids 20 are all arranged at intervals along a first direction and all extend along a second direction, and the second direction intersects the first direction. The plurality of fine grids 20 specifically include a positive fine grid 20 and a negative fine grid 20. The first direction may specifically be the width direction of the fine grid 20, that is, Figure 3 and Figure 4 the vertical direction in Figure 3 and Figure 4 ; the second direction may specifically be the length direction of the fine grid 20, that is,

[0039] the horizontal direction in

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

[0041] Specifically, the first edge area 122 is located on the side of the intermediate area 121 close to the cutting area 110. The cutting area 110 is located between two grid line areas 120, that is, the first edge area 122 is provided on both sides of the cutting area 110. A number of first connection structures 21 are provided on the fine grids 20 in the intermediate area 121, and a number of second connection structures 22 are provided on the fine grids 20 in the first edge area 122. The fine grids 20 in the intermediate area 121 are connected to the solder tape through the first connection structures 21, and the fine grids 20 in the first edge area 122 are connected to the solder tape through the second connection structures 22. The connection method of the solder tape can be specifically carried out by welding or dispensing. The area of the second connection structure 22 is larger than the area of the first connection structure 21. The widths of both the first connection structure 21 and the second connection structure 22 are larger than that of the fine grid 20, that is, both the first connection structure 21 and the second connection structure 22 are set thicker than the fine grid 20.

[0042] Each of the first connection structures 21 and each of the second connection structures 22 are specifically arranged at intervals on the fine grid 20. The first connection structure 21 and the second connection structure 22 can specifically be composed of a plurality of solder joints (which can also be called pad points); or the first connection structure 21 and the second connection structure 22 can specifically be composed of a plurality of solder joints or can be composed of a larger solder joint. Optionally, the outer contours of each of the first connection structures 21 and the second connection structures 22 can be set as trapezoidal, circular, rectangular or octagonal, etc.

[0043] Because in the cutting area 110, a position for cutting the main-gridless back-contact battery 100 needs to be reserved, and no grid lines are provided in the cutting area 110. Therefore, when the solder tape is provided in the main-gridless back-contact battery 100, no fine grid 20 grid lines are provided in the cutting area 110 to provide tension for the solder tape. Compared with the solder tape located in the grid line area 120, the tension of the part of the solder tape located in the cutting area 110 is insufficient, and poor connection is likely to occur.

[0044] Therefore, in the present utility model, since the first edge region 122 is located on the side of the middle region 121 close to the cutting region 110, and the first edge regions 122 are provided on both sides of the cutting region 110, by increasing the area of the second connection structure 22 in the first edge region 122, the area of the second connection structure 22 close to the cutting region 110 is made larger than the area of the first connection structure 21 far from the cutting region 110, that is, the contact area between the second connection structure 22 near the cutting region 110 and the solder strip is increased, achieving the effect of increasing the pulling force of the cutting region 110 on the solder strip to reduce the poor connection of the solder strip. And 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] Further, in the main-gridless back-contact battery 100, in addition to the first edge region 122, in a possible implementation manner, the grid line region 120 further includes a second edge region 123. The second edge region 123 is located on the other side of the middle region 121 close to the cutting region 110. The second edge region 123 is provided with a plurality of third connection structures 23, and the area of the third connection structure 23 is larger than the area of the first connection structure 21.

[0046] Specifically, the grid line region 120 further includes a second edge region 123. The first edge region 122 and the second edge region 123 are oppositely arranged. 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 far from the cutting region 110. The second edge region 123 can be an edge region of the main-gridless back-contact battery 100. Of course, in other embodiments, the second edge region 123 can also be a grid line region close to the cutting region.

[0047] In the present utility model, the fine grid 20 of the second edge region 123 is provided with a plurality of third connection structures 23. The fine grid 20 of the second edge region 123 is connected to the solder strip through the third connection structures 23. The connection manner of the solder strip can specifically be carried out 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. And, the width of each third connection structure 23 is greater than that of the fine grid 20, that is, the third connection structure 23 is set to be thicker than the fine grid 20.

[0048] Each of the third connection structures 23 is specifically arranged on the fine grid 20 at intervals. The third connection structure 23 can specifically be composed of a plurality of solder joints (which can also be called pad points); or, the third connection structure 23 can specifically be composed of a plurality of solder joints or can be composed of a larger solder joint. Optionally, the outer contour of each of the third connection structures 23 can be set to be trapezoidal, circular, rectangular or octagonal, etc.

[0049] In the main-gridless back-contact battery 100, the second edge region 123 is an edge portion of the main-gridless back-contact battery 100. In the main-gridless back-contact battery 100, due to the relatively concentrated stress and tension in the edge portion, the tensile force for soldering tape welding in this part is insufficient, and problems such as poor connection are likely to occur.

[0050] Therefore, in the present utility model, the second edge region 123 is an edge portion of the main-gridless back-contact battery 100. 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 soldering tape, the tensile force of the second edge region 123 on the soldering tape is increased, so as to increase the connection tensile force between the soldering tape and the fine grid 20 in the edge portion of the main-gridless back-contact battery 100, to disperse and resist the stress and tension closer to the edge of the main-gridless back-contact battery 100, achieving the effect of improving the tensile force of the soldering tape in the edge portion, improving the firmness of the soldering tape welding, stabilizing the soldering tape connection, and reducing the risk of poor soldering tape connection. And for the third connection structure 23, the number of the third connection structures 23 can be set to one or more.

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

[0052] Because when setting the soldering tape on the fine grid 20, the soldering tape is set along the width direction of the fine grid 20. For the tensile force of the main-gridless back-contact battery 100 on the soldering tape, along the second direction, for the main-gridless back-contact battery 100, the tensile force of the main-gridless back-contact battery 100 on the soldering tape is the same. Therefore, by setting the areas of the second connection structures 22 in the second direction in the main-gridless back-contact battery 100 to be equal, the tensile force of the soldering tape can be evenly distributed, reducing the risk of poor soldering tape connection caused by uneven tensile force, and achieving the effect of improving the stability of the soldering tape connection. Similarly, by setting the areas of the third connection structures 23 in the second direction in the main-gridless back-contact battery 100 to be equal, the tensile force of the soldering tape can be evenly distributed, reducing the risk of poor soldering tape connection caused by uneven tensile force, and achieving the effect of improving the stability of the soldering tape connection.

[0053] Furthermore, in a possible implementation manner, as Figures 3 to 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 tape connection in this part is insufficient, and problems such as poor solder tape connection are likely to occur. 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 tape to be stably connected, and the more likely it is to cause problems of 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 tape closer to the edge of the main-gridless back-contact battery 100 and the fine grid 20, disperse and resist the gradually increasing stress and tension closer to the edge of the main-gridless back-contact battery 100, achieve the effect of improving the tensile force of the solder tape in the edge part, improving the firmness of the solder tape connection, and reducing the risk of poor solder tape 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 to make the area of the first connection structure 21 gradually increase, or it can also be the situation of X1 = X2 < X3 = X4 < X5 = X6 to make the area of the first connection structure 21 gradually increase, which is not limited here. The situation 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 part 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 main-gridless 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 solder tape closer to the edge of the main-gridless back-contact battery 100 and the fine grid 20, disperse and resist the gradually increasing stress and tension closer to the edge of the main-gridless back-contact battery 100, achieve the effect of improving the solder tape tension of the edge part, enhancing the firmness of the solder tape connection, and reducing the risk of poor solder tape connection.

[0057] Specifically, there are multiple third connection structures 23 in the second edge region 123. Each of the third connection structures 23 is specifically arranged at intervals along the first direction. Along the first direction, the area of the third connection structure 23 gradually increases or gradually decreases. For the way of gradually increasing or gradually decreasing the area of the third connection structure 23, reference can be made to the second connection structure 22, which will not be elaborated here.

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

[0059] Furthermore, in a possible implementation manner, the length range of the first connection structure 21 is 500 μm to 700 μm.

[0060] Specifically, because 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, increasing the challenges and complexity in the solder tape connection process; and when the length of the first connection structure 21 is too long, it may also short-circuit adjacent solder tapes, affecting the battery efficiency of the main-gridless back-contact battery 100, resulting in the problem of damage to the main-gridless back-contact battery 100, and there will also be a problem of cost waste. Therefore, by setting the length range of the first connection structure 21 between 500 μm and 700 μm, the effect of both reducing the complexity of the solder tape connection and ensuring the battery efficiency of the main-gridless back-contact battery 100 can be achieved.

[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, with regard to the area relationship between the first connection structure 21 and the second connection structure 22, in a possible implementation manner, along the first direction, the length of the main-gridless back-contact battery 100 is equal to 24 times the total length of a plurality of second connection structures 22 or a plurality of third connection structures 23.

[0063] Specifically, for the main-gridless back-contact battery 100, the part of the middle region 121 is larger than the part of the first edge region 122. Therefore, the area of the first connection structure 21 provided in the middle region 121 needs to be larger than the area of the second connection structure 22 provided in the first edge region 122 to meet the need for solder ribbon connection. By setting the length of the main-gridless back-contact battery 100 to be equal to 24 times the total length of a plurality of second connection structures 22 or a plurality of third connection structures 23, more space is reserved in the middle region 121 with a larger area for arranging the first connection structure 21, providing a more stable contact for the part of the solder ribbon connection in the middle region 121, and further achieving the effect of reducing the problem of poor solder ribbon connection.

[0064] Optionally, with regard to 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 to 190000 μm 2 ; the width range of the second connection structure 22 and / or the third connection structure 23 is 95 μm to 105 μm; the length range of the second connection structure 22 and / or the third connection structure 23 is 500 μm to 1800 μm.

[0065] Specifically, the area range of a single second connection structure 22 is set between 46000 μm 2 and 190000 μm 2 ; the area range of a single third connection structure 23 is set between 46000 μm 2 and 190000 μm 2between. Because 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 solder tape is insufficient, and the connection strength during connection of the solder tape will be insufficient, and problems such as poor connection of the solder tape are likely to occur; 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 of 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-gridless back-contact battery 100, causing problems of damage to the main-gridless back-contact battery 100, and also problems of cost waste. Therefore, by setting the area range of the second connection structure 22 and / or the third connection structure 23 to be set between 46000μm 2 and 190000μm 2 between, it is possible to achieve the effect of both maintaining the connection strength of the solder tape and ensuring the battery efficiency of the main-gridless back-contact battery 100.

[0066] In such an embodiment, the area of the second connection structure 22 and / or the third connection structure 23 can be, for example, 60000μm 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 any value within the range of 46000μm 2 to 190000μm 2 range.

[0067] Moreover, the width range of a single second connection structure 22 and / or third connection structure 23 is between 95 μm and 105 μm. Because when the width of the second connection structure 22 and / or third connection structure 23 is too small, the precision requirement for positioning the second connection structure 22 and / or 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 third connection structure 23, increasing the challenges and complexity in the solder strip connection process; and when the width of the second connection structure 22 and / or third connection structure 23 is too wide, it may also short-circuit adjacent fine grids 20, affecting the battery efficiency of the main-gridless back-contact battery 100, resulting in the problem of damage to the main-gridless back-contact battery 100, and there will also be a problem of cost waste. Therefore, by setting the width range of the second connection structure 22 and / or third connection structure 23 to be between 95 μm and 105 μm, it is possible to achieve the effect of both reducing the complexity of the solder strip connection and ensuring the battery efficiency of the main-gridless back-contact battery 100. Preferably, the width of the second connection structure 22 and / or third connection structure 23 can be set to 100 μm.

[0068] In addition, the length range of a single second connection structure 22 and / or third connection structure 23 is between 500 μm and 1800 μm. Because when the length of the second connection structure 22 and / or third connection structure 23 is too small, the precision requirement for positioning the second connection structure 22 and / or 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 third connection structure 23, increasing the challenges and complexity in the solder strip connection process; and when the length of the second connection structure 22 and / or third connection structure 23 is too long, it may also short-circuit adjacent solder strips, affecting the battery efficiency of the main-gridless back-contact battery 100, resulting in the problem of damage to the main-gridless back-contact battery 100, and there will also be a problem of cost waste. Therefore, by setting the length range of the second connection structure 22 and / or third connection structure 23 to be between 500 μm and 1800 μm, it is possible to achieve the effect of both reducing the complexity of the solder strip connection and ensuring the battery efficiency of the main-gridless back-contact battery 100.

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

[0070] Moreover, in a possible implementation, 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 as rectangles. 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, for the material of the second connection structure 22 and / or the third connection structure 23, in a possible implementation, the second connection structure 22 and / or the third connection structure 23 is made of non-burn-through paste.

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

[0075] Specifically, the second connection structure 22 and / or the third connection structure 23 can also be made of burn-through paste. Since the burn-through paste can penetrate the protective layer at high temperature and directly contact the doping material of the main-gridless back-contact cell 100, a stronger electrical connection is formed, thereby achieving the effect of improving the efficiency of the main-gridless back-contact cell 100. Moreover, the fine grid 20 is made of burn-through paste, that is, the fine grid 20 in the first edge region 122 and the second connection structure 22 in the fine grid 20 are both made of burn-through paste, and / or the fine grid 20 in the second edge region 123 and the third connection structure 23 in the fine grid 20 are both made of burn-through paste. During preparation, the consistency of the fine grid 20 and the second connection structure 22 paste and / or the fine grid 20 and the third connection structure 23 paste can be maintained, achieving the effect of reducing costs.

[0076] Further, please refer to Figure 4 , the main-gridless back-contact cell 100 in the present utility model further includes a third edge region 124. The first edge region 122 is located between the third edge region 124 and the cutting region 110. A plurality of first conductive structures 30 are provided in the third edge region 124. The plurality of first conductive structures 30 are all arranged at intervals along the second direction and all extend along the first direction. The first conductive structure 30 is located on the side of the fine grid 20 facing the silicon substrate 10. The first conductive structure 30 is specifically connected to the fine grid 20 with the same polarity in the third edge region 124. Along the first direction, the first conductive structure 30 is further connected to one second connection structure 22 closest to the third edge region 124. The first conductive structure 30 can be a positive electrode or a negative electrode.

[0077] Specifically, due to the relatively concentrated stress and tensile force in the edge part of the main-gridless back-contact cell 100, there may be a risk of the solder tape being pulled and cracked in this area. Therefore, a third edge region 124 is provided in the main-gridless back-contact cell 100. The first edge region 122 is located between the third edge region 124 and the cutting region 110. That is, compared with the first edge region 122, the third edge region 124 is closer to the cutting region 110. A plurality of first conductive structures 30 are provided in the third edge region 124. The first conductive structure 30 is located on the side of the fine grid 20 facing the silicon substrate 10. That is, in the third edge region 124, the fine grid 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 grid or other conductive structures.

[0078] In the third edge region 124, by arranging the first conductive structure 30, the tensile force of the welding ribbon at the edge portion of a main-gridless back-contact battery 100 formed by cutting from the cutting region 110 can be shared, thereby reducing the risk of the welding ribbon at the edge portion of the main-gridless back-contact battery 100 being broken and cracked due to tensile force, ensuring the connection stability between the welding ribbon and the main-gridless back-contact battery 100, and enhancing the performance of the main-gridless back-contact battery 100.

[0079] Furthermore, please refer to Figure 4 , the main-gridless back-contact battery 100 in the present utility model further includes a fourth edge region 125, and the fourth edge region 125 is located between the second edge region 123 and the middle region 121; a plurality of second conductive structures 40 are arranged in the fourth edge region 125, the plurality of second conductive structures 40 are all arranged at intervals along the second direction and all extend along the first direction, and the second conductive structure 40 is located on the side of the fine grid 20 facing the silicon substrate 10. The second conductive structure 40 is specifically connected to the fine grid 20 with the same polarity in the fourth edge region 125. Along the first direction, the second conductive structure 40 is further connected to a third connection 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 tensile force at the edge portion of the main-gridless back-contact battery 100 are relatively concentrated, there is a risk that the welding ribbon may be broken and cracked in this area. Therefore, the fourth edge region 125 is provided in the main-gridless back-contact battery 100. The first edge region 122 is located between the fourth edge region 125 and the middle region 121. That is, compared with the second edge region 123, the fourth edge region 125 is closer to the edge of the main-gridless back-contact battery 100. A plurality of second conductive structures 40 are arranged in the fourth edge region 125, and the second conductive structure 40 is located on the side of the fine grid 20 facing the silicon substrate 10. That is, in the fourth edge region 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 structures.

[0081] In the fourth edge region 125, by arranging the second conductive structure 40, the tensile force of the welding ribbon at the edge portion of the main-gridless back-contact battery 100 can be shared, thereby reducing the risk of the welding ribbon at the edge portion of the main-gridless back-contact battery 100 being broken and cracked due to tensile force, ensuring the connection stability between the welding ribbon and the main-gridless back-contact battery 100, and enhancing the performance of the main-gridless back-contact battery 100.

[0082] In the description of this specification, the descriptions with reference to terms such as "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. 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 are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A passivated emitter and rear contact (PERC) cell, characterized in that, Including: A silicon substrate and a plurality of fine grids disposed on the silicon substrate; the plurality of fine grids are arranged at intervals along a first direction and all extend along a second direction, and the first direction intersects the second direction. The main-gridless back-contact battery includes a cutting area and a plurality of grid-line areas, and the cutting area is located between two of the grid-line areas. The grid-line area includes an intermediate area and a first edge area, the first edge area is located on a side of the main-gridless back-contact battery away from the cutting area, a plurality of first connection structures are provided on the fine grids in the intermediate area, a plurality of second connection structures are provided on the fine grids in the first edge area, and the area of the second connection structure is larger than the area of the first connection structure.

2. The back-contact cell without main grid according to claim 1, characterized in that, The grid-line area further includes a second edge area, the second edge area is located on a side of the main-gridless back-contact battery away from the cutting area, and a plurality of third connection structures are provided on the fine grids in the second edge area, and the area of the third connection structure is larger than the area of the first connection structure.

3. The back-contact cell without main grid according to claim 2, wherein The number of the second connection structures is multiple, and along the second direction, the areas of the second connection structures are equal; and / or the number of the third connection structures is multiple, and along the second direction, the areas of the third connection structures are equal.

4. The back-contact cell without main grid according to claim 2, wherein The number of the second connection structures is multiple, and along the first direction, the area of the second connection structure increases or gradually decreases; and / or the number of the third connection structures is multiple, and along the first direction, the area of the third connection structure gradually increases or gradually decreases.

5. The back-contact cell without main grid according to claim 1, wherein The number of the first connection structures is multiple, and along the first direction and / or the second direction, the areas of the first connection structures are equal.

6. The back-contact cell without main grid according to claim 2, characterized in that, Along the first direction, the length of the main-gridless back-contact battery 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 back-contact cell without main grid according to claim 2, characterized in that, The area range of the second connection structure and / or the third connection structure is 46000μm 2 to 190000μm 2 .

8. The back-contact cell without main grid according to claim 2, wherein 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 back-contact cell without main grid according to claim 2, wherein The width range of the second connection structure and / or the third connection structure is from 95 μm to 105 μm.

10. The back-contact cell without main grid according to claim 2, wherein The length range of the second connection structure and / or the third connection structure is from 500 μm to 1800 μm.

11. The back-contact cell without main grid according to claim 1, characterized in that, The length range of the first connection structure is from 500 μm to 700 μm.

12. The back-contact cell without main grid according to claim 2, wherein The second connection structure and / or the third connection structure is made of non-burn-through paste.

13. The back-contact cell without main grid according to claim 2, wherein The second connection structure and / or the third connection structure is made of burn-through paste.

14. The back-contact cell without main grid according to claim 1, characterized in that, It further includes a third edge area, and the third edge area is located between the first edge area and the cutting area. A plurality of first conductive structures are provided in the third edge area, the plurality of first conductive structures are arranged at intervals along the second direction and all extend along the first direction, and the first conductive structures are located on a side of the fine grids facing the silicon substrate.

15. The back-contact cell without main grid according to claim 2, wherein It further includes a fourth edge area, and the second edge area is located between the fourth edge area and the intermediate area. A plurality of second conductive structures are provided in the fourth edge region. The plurality of second conductive structures are arranged at intervals along the second direction and extend along the first direction. The second conductive structures are located on a side of the fine grid facing the silicon substrate.

16. A battery component, characterized in that, It includes the main-gridless back-contact battery according to any one of claims 1 to 15.

17. A photovoltaic system, characterized in that, It includes the battery assembly according to claim 16.

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