Back contact battery assembly and photovoltaic system

Abstract

The invention is suitable for the field of photovoltaic technology, and provides a back contact battery assembly and a photovoltaic system, and the back contact battery assembly comprises a first battery string, a welding strip, and a bus bar. The first battery string comprises a plurality of back contact solar battery pieces which are alternately arranged along a first direction, the adjacent back contact solar battery pieces are connected in series through welding strips, and the back contact solar battery pieces comprise first battery pieces and second battery pieces which are arranged along the first direction; the back contact solar cell piece is provided with a first edge and a second edge which are oppositely arranged, and edge lines are arranged at the positions close to the first edge and the second edge at intervals. The bus bar is arranged on the second battery piece, the orthographic projection of the bus bar is completely overlapped with the connecting point close to the first edge of the second battery piece and is at least partially overlapped with the connecting line, and the covered length of the connecting line accounts for 20%-90% of the total length of the connecting line, so that short circuit and subfissure caused by lap joint of the welding strip are avoided, and the reject ratio is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaic, and particularly relates to a back contact cell module and a photovoltaic system. BACKGROUND

[0002] The hidden busbar photovoltaic module improves the front light receiving area of the module and the power of the module by placing the busbar at the back of the cell. However, after placing the busbar at the back of the cell, the height of the busbar placement area is obviously higher than that of the non-busbar area, and the busbar area and the non-busbar area form an obvious height difference. The height difference causes a low pressure area near the edge of the busbar during the lamination process, and the PAD points located in the area are insufficiently stressed during the lamination process, which easily causes the welding strip to deviate and the virtual welding to be poor, affecting the power of the module and the long-term reliability during outdoor operation. SUMMARY

[0003] The application provides a back contact cell module, and aims to solve the problem that the PAD points are insufficiently stressed during the lamination process, which easily causes the welding strip to deviate and the virtual welding to be poor.

[0004] The application is implemented as follows: a back contact cell module, comprising: a first cell string, a welding strip, and a busbar. The first cell string comprises a plurality of back contact solar cell pieces arranged alternately along a first direction, and adjacent back contact solar cell pieces are connected in series by the welding strip, and the back contact solar cell piece comprises a first cell piece and a second cell piece arranged along the first direction. The back contact solar cell piece has a first edge and a second edge arranged oppositely, and an edge line is arranged at a position close to the first edge and the second edge, respectively, and the edge line close to the first edge is arranged oppositely to the edge line close to the second edge. The edge line comprises a connection point and a connection line, one end of the connection line is connected to the connection point, and the other end extends to the closest first edge or second edge. The first edge of the second cell piece is close to the second edge of the first cell piece, the busbar is arranged on the second cell piece and extends along a second direction, the orthographic projection of the busbar completely overlaps the connection point close to the first edge of the second cell piece, and at least partially overlaps the connection line, the length of the connection line covered accounts for 20% to 90% of the total length of the connection line, and the first direction intersects the second direction.

[0005] Optionally, the solder strip extends along the first direction and is arranged to electrically connect the back surface of the back contact solar cell group and the edge line, and comprises a first solder strip on the first cell and a second solder strip on the second cell, the first solder strip has an extension segment near one end of the bus bar to electrically connect with the bus bar, and the second solder strip has an end near the bus bar to electrically connect with the connecting point.

[0006] Optionally, the end of the first solder strip connected with the bus bar is arranged above the bus bar, and the second solder strip intersecting with the bus bar is arranged below the bus bar.

[0007] Optionally, the back contact solar cell group further comprises an isolation strip arranged along the second direction, and the isolation strip is arranged between the second solder strip and the bus bar.

[0008] Optionally, the width of the isolation strip is greater than or equal to the width of the bus bar.

[0009] Optionally, the axes of the orthographic projections of the first solder strip and the second solder strip along the first direction are collinear.

[0010] Optionally, the back contact solar cell group is arranged in an overlapping manner along the first direction.

[0011] Optionally, the bus bar has a spacing from the first edge of the second cell.

[0012] Optionally, the first cell is an end cell of the cell string.

[0013] Optionally, the back contact solar cell group further comprises a second cell string, and the first solder strip connects the first cell string and the second cell string.

[0014] The application further provides a photovoltaic system comprising the back contact cell assembly.

[0015] The application has the advantages that the edge line is arranged to collect the carriers generated by the cell edges, thereby avoiding waste of the carriers. The back contact solar cell is connected in series by the solder strip, and the current is collected by the bus bar. The orthographic projection of the bus bar completely overlaps the connecting point near the first edge of the second cell, thereby effectively reducing the generation of welding defects such as virtual welding and delamination, and greatly improving the welding strength. Meanwhile, the orthographic projection of the bus bar at least partially overlaps the connecting line, the length of the connecting line covered by the bus bar accounts for 20% to 90% of the total length of the connecting line, thereby avoiding short circuit and hidden cracks of the solder strip, and reducing the defective rate. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic diagram of the back contact solar cell provided by the application; Figure 2 is a structural schematic diagram of a back contact battery assembly provided by the present application; Figure 3 is another structural schematic diagram of a back contact battery assembly provided by the present application.

[0017] Explanation of reference signs: 100, back contact battery assembly; 110, first battery string; 111, back contact solar cell piece; 1111, first edge; 1112, second edge; 112, edge line; 1121, connection point; 1122, connection line; 101, first cell piece; 102, second cell piece; 120, solder strip; 121, first solder strip; 122, second solder strip; 130, bus bar; 140, second battery string. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the accompanying drawings and examples. The examples of the described embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The examples described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0020] In addition, the terms "first", "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0021] In the description of the present application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0023] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0024] The present application sets the edge line to collect the carriers generated by the battery edge, avoiding the waste of carriers. The back contact solar cell piece is connected in series through the solder strip, and the current is collected through the bus bar. The orthographic projection of the bus bar completely overlaps the connection point close to the first edge of the second solar cell piece, which can effectively reduce the generation of welding defects such as false welding and welding, thereby greatly improving the welding strength. At the same time, the orthographic projection of the bus bar at least partially overlaps the connecting line, and the length of the connecting line covered accounts for 20% to 90% of the total length of the connecting line, avoiding the lap joint short circuit and hidden crack of the solder strip, and reducing the defective rate.

[0025] Example One The embodiment provides a back contact battery assembly 100, characterized by comprising: a first battery string 110, a solder strip 120, and a bus bar 130. The first battery string 110 includes a plurality of back contact solar cell pieces 111 arranged alternately along a first direction, and adjacent back contact solar cell pieces 111 are connected in series by a solder strip 120. The back contact solar cell piece 111 includes a first cell piece 101 and a second cell piece 102 arranged along the first direction. The back contact solar cell piece 111 has a first edge 1111 and a second edge 1112 arranged oppositely, and an edge line 112 is arranged at a position close to the first edge 1111 and the second edge 1112, respectively. The edge line 112 includes a connection point 1121 and a connection line 1122, and one end of the connection line 1122 is connected to the connection point 1121, and the other end extends to the closest first edge 1111 or second edge 1112. The first edge 1111 of the second cell piece 102 is close to the second edge 1112 of the first cell piece 101, and a bus bar 130 is arranged on the second cell piece 102 and extends along a second direction. The bus bar 130 has a projection completely overlapping the connection point 1121 close to the first edge 1111 of the second cell piece 102 and at least partially overlapping the connection line 1122. The length of the connection line 1122 covered accounts for 20% to 90% of the total length of the connection line 1122. The first direction intersects the second direction.

[0026] The first battery string 110 includes a plurality of back contact solar cell pieces 111, and the positive electrode and the negative electrode of the back contact solar cell piece 111 are arranged on the back surface of the back contact solar cell piece 111. Compared with the conventional structure in which the positive electrode and the negative electrode are arranged on the front surface and the back surface of the back contact solar cell piece 111, respectively, the structure reduces the shading of the front electrode to light and improves the absorption efficiency of the solar cell piece to sunlight. In the back contact solar cell piece 111, the positive electrode and the negative electrode extend along a second direction and are arranged alternately along a first direction.

[0027] The second direction intersects the first direction, as shown in Figure 2 and Figure 3 The first direction can be the longitudinal direction of the back contact battery, and the second direction can be the transverse direction of the back contact battery, and the two directions are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, the two directions can be diagonal directions of the silicon substrate, and the specific embodiments are not limited herein.

[0028] The back contact solar cell piece 111 has a first edge 1111 and a second edge 1112 oppositely arranged, and the first edge 1111 and the second edge 1112 extend along a second direction. A plurality of edge lines 112 are arranged at positions close to the first edge 1111 and the second edge 1112, respectively, for connecting the electrodes of the same polarity close to the edges of the cell. The edge lines 112 connecting the positive electrodes and the edge lines 112 connecting the negative electrodes are alternately arranged along the second direction at the first edge 1111 and the second edge 1112.

[0029] The edge line 112 includes a connection point 1121 and a connection line 1122, one end of the connection line 1122 being connected to the connection point 1121, and the other end extending to the closest first edge 1111 or second edge 1112. The connection line 1122 is electrically connected to a plurality of positive electrodes or negative electrodes close to the edges of the cell, collects the carriers transported on the electrodes close to the edges of the cell, and collects the collected carriers on the connection point 1121. Specifically, the edge line 112 includes a first polarity edge line 112 and a second polarity edge line 112, the first polarity edge line 112 being electrically connected to the positive electrode, and the second polarity edge line 112 being electrically connected to the negative electrode.

[0030] The back contact solar cell pieces 111 are arranged along a first direction, and the adjacent cell pieces can have a spacing or can overlap each other, which is not limited herein. The back contact solar cell pieces 111 include a first cell piece 101 and a second cell piece 102, and the first cell piece 101 and the second cell piece 102 are arranged along the first direction, that is, the second cell piece 102 is arranged after the arrangement of the first cell piece 101 is completed. Specifically, the first cell piece 101 and the second cell piece 102 do not represent the order of the cell pieces in the cell string, and the first cell piece 101 can be an end cell piece (the first cell piece in the cell string) or a cell piece of other order in the cell string (except the last cell piece).

[0031] The first edge 1111 of the second cell piece 102 is close to the second edge 1112 of the first cell piece 101, and the bus bar 130 extends along the second direction and is arranged at a position close to the first edge 1111 of the second cell piece 102, which can hide the bus bar 130 and make the surface of the cell module present a more uniform visual effect. Specifically, the orthographic projection of the bus bar 130 can completely fall on the second cell piece 102, or part of the orthographic projection of the bus bar 130 can fall on the second cell piece 102, which is not limited herein.

[0032] The bus bar 130 is used to collect the current carriers on the solder strip 120, the orthographic projection of the bus bar 130 completely overlaps the connecting point 1121 close to the first edge 1111 of the second cell 102, and the bus bar 130 can generate uniform and concentrated pressure on the connecting point 1121 during lamination. Since the connecting point 1121 is a key part of the electrical connection between the cells, sufficient pressure can make the solder better fill the gap of the connecting point 1121, enhance the bonding force between the solder and the cell and the bus bar 130, and effectively reduce the generation of welding defects such as false welding and soldering, thereby greatly improving the welding strength.

[0033] The orthographic projection of the bus bar 130 at least partially overlaps the connecting line 1122, the length of the connecting line 1122 covered accounts for 20% to 90% of the total length of the connecting line 1122, and the first direction intersects the second direction. When the length of the connecting line 1122 covered accounts for less than 20% of the total length of the connecting line 1122, the head area of the solder strip 120 at the bottom of the bus bar 130 cannot be completely covered and pressed by the bus bar 130, which is easy to cause the head of the solder strip 120 to be raised, the insulation strip to be pierced, and the short circuit caused by the lap joint of the solder strip 120 with the solder strip 120 of different polarity. When the length of the connecting line 1122 covered accounts for more than 90% of the total length of the connecting line 1122, the bus bar 130 is closer to the cell stack, and the edge of the bus bar 130 is easy to be chipped during the lamination process, causing the edge of the cell to be chipped.

[0034] Specifically, in the laboratory, a number of cells with different proportions of the length of the connecting line 1122 covered by the orthographic projection of the bus bar 130 to the total length of the connecting line 1122 are tested, and the following experimental data is obtained: From the above experimental results, it can be seen that when the length of the connecting line 1122 covered accounts for 20% to 90% of the total length of the connecting line 1122, the defective rate of the cell is relatively low and remains within 1%.

[0035] In the embodiment, the present application collects the current carriers generated by the edge line 112 to the cell edge to avoid waste of the current carriers. The back contact solar cell 111 is connected in series by the solder strip 120, and the current is collected by the bus bar 130. The orthographic projection of the bus bar 130 completely overlaps the connecting point 1121 close to the first edge 1111 of the second cell 102, which can effectively reduce the generation of welding defects such as false welding and soldering, thereby greatly improving the welding strength. At the same time, the orthographic projection of the bus bar 130 at least partially overlaps the connecting line 1122, the length of the connecting line 1122 covered accounts for 20% to 90% of the total length of the connecting line 1122, which avoids the lap joint short circuit and hidden crack of the solder strip 120 and reduces the defective rate.

[0036] Example Two In some embodiments, the solder ribbons 120 extend along a first direction and are arranged to electrically connect the back surface of the group of back contact solar cell pieces 111 and the edge line 112, including a first solder ribbon 121 on the first cell piece 101 and a second solder ribbon 122 on the second cell piece 102, the first solder ribbon 121 has an extension section at one end close to the bus bar 130 to electrically connect with the bus bar 130, and the second solder ribbon 122 has an end close to the bus bar 130 to electrically connect with the connection point 1121.

[0037] The solder ribbons 120 are used to collect the carriers generated on the back contact solar cell pieces 111. Specifically, the solder ribbons 120 can be used to connect two adjacent back contact solar cell pieces 111, or can be arranged only on the end cell pieces to collect the carriers on the end cell pieces. The solder ribbons 120 include the first solder ribbon 121 and the second solder ribbon 122, wherein the first solder ribbon 121 is arranged on the first cell piece 101, one end of the first solder ribbon 121 has an extension section to electrically connect with the bus bar 130, and the second solder ribbon 122 is arranged on the second cell piece 102 and is not electrically connected with the bus bar 130. The second solder ribbon 122 connects the adjacent second cell piece 102 and other cell pieces (not the first cell piece 101), and there is a certain spacing between the second solder ribbon 122 and the bus bar 130, and the second solder ribbon 122 and the bus bar 130 are insulated. It can be understood that the solder ribbons 120 also include other connecting solder ribbons 120 to connect adjacent back contact solar cell pieces 111, for example, arranged across the first cell piece 101 and the second cell piece 102 to connect the first cell piece 101 and the second cell piece 102 in series.

[0038] The end of the second solder ribbon 122 close to the bus bar 130 is electrically connected with the connection point 1121, and the connection line 1122 is connected with the connection point 1121, that is, the second solder ribbon 122 can collect the carriers on the connection line 1122 through the connection point 1121. It should be noted that the connection line 1122 electrically connected with the second solder ribbon 122 is provided with an insulating medium between the bus bar 130 to avoid the bus bar 130 conducting through the connection line 1122 and the second solder ribbon 122.

[0039] Example Three In some embodiments, the end of the first solder ribbon 121 connected with the bus bar 130 is arranged above the bus bar 130, and the second solder ribbon 122 is arranged below the bus bar 130.

[0040] The extension section of the first solder ribbon 121 is overlapped on the bus bar 130 and contacts with the side of the bus bar 130 away from the back contact solar cell pieces 111. When the back surface of the contacted cell piece is placed upward, the first solder ribbon 121 and the bus bar 130 form a spatial positional relationship of top and bottom.

[0041] The second solder strip 122 is connected to the connection point 1121, and the positive projection of the bus bar 130 covers the connection point 1121, that is, the second solder strip 122 is partially covered by the positive projection of the bus bar 130. The second solder strip 122 is arranged on the side of the bus bar 130 facing the back of the back contact solar cell 111, but cannot be in direct contact with the bus bar 130, and an insulating medium is arranged between the two. When the back of the contacted cell is placed upward, the second solder strip 122 is arranged below the bus bar 130.

[0042] During the lamination process, the device will apply a large pressure to the battery assembly to ensure that the layers of materials are tightly combined. The extended section of the first solder strip 121 is arranged above the bus bar 130, and the extended section deforms along the outer contour of the bus bar 130 during lamination. The first solder strip 121 and the bus bar 130 are usually made of different materials and have different mechanical properties such as hardness and elastic modulus. In general, the solder strip 120 is relatively thin and soft, and the width of the solder strip 120 is also smaller than the width of the bus bar 130, so it is less likely to break during deformation.

[0043] Further, the back contact battery assembly 100 further comprises an isolation strip arranged along the second direction. The isolation strip is arranged between the second solder strip 122 and the bus bar 130.

[0044] The isolation strip and the bus bar 130 are arranged in layers, and the isolation strip is arranged on the side of the bus bar 130 facing the back of the back contact cell. The isolation strip is made of insulating material and plays a role of isolation and protection. The side of the isolation strip facing the back of the back contact cell acts as a safety barrier to isolate the bus bar 130 from the device below, avoiding the bus bar 130 from being in electrical connection with the device below (such as the cell, other circuits, etc.), thereby avoiding short circuit, damage to the battery, and even safety accidents.

[0045] Further, the width of the isolation strip is greater than or equal to the width of the bus bar 130.

[0046] The entire bottom and side of the bus bar 130 can be covered by the isolation strip, thereby minimizing the possibility of the bus bar 130 contacting the device below, thereby enhancing the insulation effect.

[0047] Example Four In some embodiments, the axes of the positive projections of the first solder strip 121 and the second solder strip 122 are collinear along the first direction. It can be understood that the center lines of the two solder strips 120 on the projection plane are on the same straight line, and the collinear arrangement reduces the resistance of current transmission, reduces the resistance, improves the conductivity efficiency of the battery, and at the same time, the first solder strip 121 and the second solder strip 122 are easier to arrange and process.

[0048] In some embodiments, the back contact solar cell 111 is arranged in an overlapping manner along the first direction.

[0049] That is, the back contact solar cell 111 is arranged along the first direction, and adjacent back contact solar cells 111 have an overlapping area. Specifically, the back contact solar cell 111 has a light-receiving surface and a back surface arranged oppositely, and the back surface of the front back contact solar cell 111 close to the second edge 1112 is in contact with the light-receiving surface of the rear back contact solar cell 111 close to the first edge, and the overlapping area of the two back contact solar cells 111 is the overlapping area.

[0050] The overlapping arrangement can increase the light-receiving area of the cell. In the same space, the overlapping arrangement can expose more cells to sunlight, thereby improving the utilization of sunlight. At the same time, this arrangement can also enhance the structural stability of the cell group. The overlapping parts between adjacent cells can support each other, reducing the possibility of displacement or damage of the cells when subjected to external forces.

[0051] In some embodiments, the bus bar 130 has a spacing from the first edge 1111 of the second cell 102.

[0052] The cell edge can have some burrs or uneven places. If the bus bar 130 directly contacts the edge, it is easy to cause short circuit, affecting the normal work of the cell group. In addition, the spacing also provides a certain expansion space for the cell when it expands and contracts due to heat, avoiding damage caused by the extrusion of the bus bar 130 and the cell edge due to thermal expansion and contraction.

[0053] In some embodiments, the distance between the bus bar 130 and the adjacent connection point 1121 is 0-5mm. Specifically, it can be 0mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or other values between 0-5mm, which are not limited herein. Within this range, the bus bar 130 is relatively close to the adjacent connection point 1121 but has a certain space. A suitable distance can ensure the efficiency and stability of current transmission. If the distance is greater than 5mm, the current transmission path becomes longer, the resistance increases, and the energy loss increases. When the bus bar 130 is tangent to the adjacent connection point 1121, the distance between them is 0.

[0054] Example Five In some embodiments, the first cell 101 is an end cell of the cell string.

[0055] The end cell is the first cell in the cell string, such as Figure 2As shown. The first cell piece 101 is an end cell piece, specifically, in the whole back contact cell module 100, the first cell string 110 is the first cell string in the cell string arrangement, that is, the first cell piece 101 is the cell piece closest to the edge of the back contact cell module 100. At this time, the first welding strip 121 is arranged on the first cell piece 101 to collect the carriers on the first cell piece 101 and is electrically connected with the bus bar 130.

[0056] In addition, in the whole back contact cell module 100, the first cell string 110 can not be the first cell string in the cell string arrangement, that is, the first cell piece 101 has other cell strings on the other side opposite to the second cell piece 102. For example, as shown, the first welding strip 121 connects the first cell string 110 and the second cell string 140, at this time, the first welding strip 121 is responsible for connecting the adjacent first cell piece 101 and the cell piece in the second cell string 140 in series to ensure smooth conduction of current in the cell string, and is electrically connected with the bus bar 130 to transmit the current generated by the cell string to the bus bar 130 for further output of electric energy. Figure 3

[0057] Example Six The embodiment provides a photovoltaic system comprising the back contact cell module 100.

[0058] The photovoltaic system has the same beneficial effects as the back contact cell module 100, and details are not repeated here.

[0059] The photovoltaic system can be applied in a photovoltaic power station, for example, a ground power station, a roof power station, a water surface power station and the like, and can also be applied in a device or apparatus using solar energy to generate electricity, for example, a user solar power source, a solar street lamp, a solar car, a solar building and the like. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields requiring solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system can comprise a photovoltaic array, a bus box and an inverter, the photovoltaic array can be an array combination of a plurality of cell modules, for example, a plurality of cell modules can form a plurality of photovoltaic arrays, the photovoltaic array is connected with the bus box, the bus box can converge the current generated by the photovoltaic array, the converged current flows through the inverter to be converted into alternating current required by a power grid, and then is connected with the power grid to realize solar power supply.

[0060] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. A back-contact battery assembly, characterized in that, include: First battery string, solder strip, busbar; The first battery string includes a plurality of back-contact solar cells arranged alternately along a first direction, and adjacent back-contact solar cells are connected in series by the solder strip. The back-contact solar cells include a first cell and a second cell arranged along the first direction. The back-contact solar cell has a first edge and a second edge that are disposed opposite to each other. Edge lines are disposed at intervals near the first edge and the second edge, respectively. The edge lines near the first edge are disposed opposite to the edge lines near the second edge. The edge line includes a connection point and a connecting line, one end of which is connected to the connection point and the other end extends toward the nearest first edge or second edge; The first edge of the second battery cell is close to the second edge of the first battery cell. The busbar is disposed on the second battery cell and extends along the second direction. The orthographic projection of the busbar completely overlaps with the connection point near the first edge of the second battery cell and at least partially overlaps with the connecting line. The length of the connecting line covered accounts for 20% to 90% of the total length of the connecting line. The first direction intersects the second direction.

2. The back contact battery assembly as described in claim 1, characterized in that, The solder strips extend along the first direction and are arranged on the back side of the back-contact solar cell array, electrically connected to the edge line. The solder strips include a first solder strip on the first cell and a second solder strip on the second cell. The first solder strip has an extension at one end near the busbar that is electrically connected to the busbar, and the second solder strip has an extension at one end near the busbar that is electrically connected to the connection point.

3. The back contact battery assembly as described in claim 2, characterized in that, The first solder strip is positioned above the busbar at one end, and the second solder strip, which intersects the busbar, is positioned below the busbar.

4. The back contact battery assembly as described in claim 3, characterized in that, It also includes a separator strip that extends along the second direction and is located between the second solder strip and the busbar.

5. The back contact battery assembly as described in claim 4, characterized in that, The width of the isolation strip is greater than or equal to the width of the busbar.

6. The back contact battery assembly as described in claim 2, characterized in that, The axes of the orthogonal projections of the first and second solder strips are collinear along the first direction.

7. The back contact battery assembly as claimed in claim 1, characterized in that, The back-contact solar cells are arranged in an overlapping pattern along the first direction.

8. The back contact battery assembly as claimed in claim 1, characterized in that, The busbar has a gap with the first edge of the second battery cell.

9. The back contact battery assembly as described in claim 2, characterized in that, The first battery cell is the end battery cell of the battery string.

10. The back contact battery assembly as claimed in claim 9, characterized in that, It also has a second battery string, and the first solder strip connects the first battery string and the second battery string.

11. A photovoltaic system, characterized in that, Includes the back contact battery assembly as described in any one of claims 1-10.

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