Back contact battery assembly and photovoltaic system

Abstract

The utility model relates to the technical field of solar cells, and provides a back contact cell assembly and a photovoltaic system, a plurality of cell string units in the back contact cell assembly are connected in series through a bus bar, each cell string unit comprises a cell string, and a cell sheet in the cell string is a one-third slice cell. At least one of the plurality of bus bars is arranged on the back surface of a battery piece of the battery string, each battery string unit is provided with a bypass diode in parallel, and the bypass diodes are connected with the battery string units in parallel through connecting wires. Therefore, the power loss of the assembly can be reduced, the anti-subfissure capability can be enhanced, the subfissure risk can be reduced, meanwhile, the generated power of the unit area of the back contact battery assembly can be improved, and the attractiveness of the back contact battery assembly can be improved.

Description

Back contact battery modules and photovoltaic systems Technical Field

[0001] This application relates to the field of solar cell technology, and more particularly to a back-contact battery module and photovoltaic system. Background Technology

[0002] Back-contact solar modules typically consist of an array of back-contact cells, comprising several back-contact cell strings. In related technologies, as cell size increases, the short-circuit current of the cells and the module continuously rises. To reduce series resistance, the cells are often halved, with the half-cells connected in series to form a cell string. These cell strings are then connected in parallel to form a half-cell module. However, even with this design, there are still technical problems such as high module power loss and a high risk of hot spots, and the half-cells also have a higher risk of microcracks.

[0003] Meanwhile, in existing technologies, the installation of busbars in photovoltaic systems requires reserving a certain amount of space on the modules for placement. This reduces the power generation per unit area of ​​the modules and also affects their aesthetics. Summary of the Invention

[0004] This application provides a back-contact battery module and a photovoltaic system.

[0005] This application is implemented as follows: the back contact battery assembly in the embodiments of this application includes:

[0006] Multiple battery string units are connected in series with each other. Each battery string unit includes three battery strings connected in parallel. Each battery string includes multiple battery cells connected in series. The multiple battery cells are connected in series by positive electrode solder strips and negative electrode solder strips. The battery cells are sliced ​​batteries formed by cutting or splitting back contact battery cells into three equal parts.

[0007] Multiple busbars are provided at both ends of each battery string unit, and multiple battery string units are connected in series through the busbars. At least one busbar is located on the back of the battery cells of the battery string; and

[0008] Multiple bypass diodes are provided, with each battery string unit having a bypass diode connected in parallel. The bypass diodes are connected in parallel to the battery string unit via connecting lines.

[0009] In some embodiments, a plurality of battery string units are arranged in parallel along a first direction, and the battery strings in the battery string units are also arranged in parallel along the first direction. A plurality of battery cells in the battery string are connected in series along a second direction, and the second direction intersects the first direction.

[0010] In some embodiments, the busbar at one end of the battery string unit is connected to the positive terminal of the battery string unit, and the busbar at the other end is connected to the negative terminal of the battery string unit. In two adjacent battery string units, the busbar connected to the positive terminal of one battery string unit is connected to the busbar connected to the negative terminal of the other battery string unit, so as to connect the two adjacent battery string units in series.

[0011] In some embodiments, the busbar connected to the positive electrode on one of the battery string units is integrally formed with the busbar connected to the negative electrode on the other battery string unit.

[0012] In some embodiments, each battery string in the battery string unit includes a first battery cell located at both ends of the battery string, and the busbar is disposed on the back of the first battery cell;

[0013] On the battery string unit, one of the busbars is disposed on the back of one of the first battery cells and is connected to the positive electrode solder strip on the first battery cell and insulated from the negative electrode solder strip on the first battery cell; the other busbar is disposed on the back of the other first battery cell and is connected to the negative electrode solder strip on the first battery cell and insulated from the positive electrode solder strip on the first battery cell.

[0014] In some embodiments, on the battery string unit, a first insulating layer is provided between one of the busbars and the negative electrode solder strip on the first battery cell, and a second insulating layer is provided between the other busbar and the positive electrode solder strip on the first battery cell.

[0015] In some embodiments, the length of the first insulating layer in the second direction is greater than or equal to the length of the busbar in the second direction; and / or, the length of the second insulating layer in the second direction is greater than or equal to the length of the busbar in the second direction.

[0016] In some embodiments, each battery string in the battery string unit includes a first battery cell located at both ends of the battery string and a second battery cell adjacent to the first battery cell;

[0017] The busbar is disposed on the back of the second battery cell, and a first insulating strip is provided between the busbar and the second battery cell; or

[0018] The busbar overlaps with both the first and second battery cells, and a first insulating strip is provided between the busbar and the first and second battery cells.

[0019] In some embodiments, the length of the first insulating strip in the second direction is greater than or equal to the length of the busbar in the second direction.

[0020] In some embodiments, at least one of the connecting wires is located on the back side of the battery string, and a second insulating strip is provided between the connecting wire and the battery cell.

[0021] In some embodiments, the length of the second insulating strip in the first direction is greater than or equal to the length of the connecting wire in the first direction.

[0022] In some embodiments, the resistance per unit length of the connecting wire is less than or equal to the resistance per unit length of the busbar.

[0023] In some embodiments, in the battery string, two adjacent battery cells partially overlap; and / or

[0024] Two adjacent battery strings in the battery string unit partially overlap; and / or

[0025] In two adjacent battery string cells, the two adjacent battery strings partially overlap.

[0026] In some embodiments, the connecting line and the bypass diode connected in parallel with the battery string unit are located between two adjacent battery strings.

[0027] In some embodiments, among the plurality of bypass diodes, at least two of the bypass diodes share the same connection line.

[0028] In some embodiments, the resistance per unit length of the connection line shared by the two bypass diodes is less than or equal to the resistance per unit length of the other connection lines.

[0029] This application also provides a photovoltaic system, which includes the back contact battery assembly described in any of the above claims.

[0030] In the back-contact solar module and photovoltaic system of this application embodiment, multiple cell string units are connected in series via busbars. Each cell string unit includes a cell string, and the cells in the cell string are one-third sliced ​​cells. At least one of the busbars is located on the back of the cells in the cell string. Each cell string unit has a bypass diode connected in parallel, which is connected in parallel to the cell string unit via a connecting wire. Thus, by using one-third sliced ​​cells in the cell string, and through the parallel connection of the cell strings within the cell string unit and the series connection between cell string units, the power loss of the module can be reduced while maintaining a final output voltage and current that is essentially the same as that of a conventional module. Furthermore, since the cell strings in the cell string unit are connected in parallel, the risk of hot spots can be effectively reduced. Also, the relatively small size of the one-third sliced ​​cells enhances resistance to microcracks and reduces the risk of microcracks. Simultaneously, the fact that at least one of the busbars is located on the back of the cell allows for the concealment of the busbar, thereby increasing the power generation per unit area of ​​the back-contact solar module and improving its aesthetics.

[0031] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0032] Figure 1 is a schematic diagram of the photovoltaic system provided in an embodiment of this application;

[0033] Figure 2 is a schematic diagram of the back contact battery assembly provided in an embodiment of this application;

[0034] Figure 3 is a schematic diagram of the battery string and busbar arrangement of the back contact battery assembly in Figure 2;

[0035] Figure 4 is another structural schematic diagram of the back contact battery assembly provided in an embodiment of this application;

[0036] Figure 5 is a schematic diagram of the battery string and busbar arrangement of the back contact battery assembly in Figure 4.

[0037] Figure 6 is another structural schematic diagram of the back contact battery assembly provided in an embodiment of this application;

[0038] Figure 7 is another structural schematic diagram of the back contact battery assembly provided in an embodiment of this application;

[0039] Figure 8 is another structural schematic diagram of the back contact battery assembly provided in an embodiment of this application;

[0040] Figure 9 is another structural schematic diagram of the back contact battery assembly provided in the embodiment of this application.

[0041] Explanation of key component symbols:

[0042] Photovoltaic system 1000, back contact battery module 100, battery string unit 10, battery string 11, battery cell 111, positive electrode solder strip 112, negative electrode solder strip 113, busbar 20, bypass diode 30, connecting wire 40, first insulating layer 50, second insulating layer 60, first insulating strip 70, second insulating strip 80. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0044] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0047] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0049] Referring to Figure 1, the photovoltaic system 1000 in this embodiment may include at least one back-contact battery module 100 as described in this embodiment. In the photovoltaic system 1000, the back-contact battery modules 100 may be electrically connected in parallel or in series, depending on actual needs.

[0050] In the embodiments of this application, the photovoltaic system 1000 can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system 1000 are not limited to these; that is to say, the photovoltaic system 1000 can be applied in all fields that require the use of solar energy to generate electricity.

[0051] Taking a photovoltaic power generation system network as an example, the photovoltaic system 1000 may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules. For example, multiple battery modules may form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can combine the current generated by the photovoltaic array. The combined current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to realize solar power supply.

[0052] Please refer to Figures 2-5. The back contact battery in this embodiment may include multiple battery string units 10, multiple busbars 20, and multiple bypass diodes 30.

[0053] Multiple battery string units 10 are connected in series. Each battery string unit 10 includes three battery strings 11 connected in parallel. Inside each battery string unit 10, the three battery strings 11 can be arranged in parallel. Each battery string 11 includes multiple battery cells 111 connected in series. The number of battery cells 111 in each battery string 11 can be equal. In each battery string 11, the multiple battery cells 111 are connected in series via positive electrode solder strips 112 and negative electrode solder strips 113. The battery cells 111 in the battery string 11 are sliced ​​batteries formed by cutting or splitting back-contact battery cells into thirds. That is to say, the battery cells 111 in the battery string 11 are all one-third sliced ​​batteries.

[0054] Each battery string unit 10 has a busbar 20 at both ends. Multiple battery string units 10 are connected in series through the busbars 20. At least one busbar 20 is located on the back of the battery cells 111 of the battery string 11 to achieve back-side concealment of at least one busbar 20. Each battery string unit 10 is connected in parallel with a bypass diode 30. The bypass diode 30 is connected in parallel with the corresponding battery string unit 10 through a connecting wire 40. The number of bypass diodes 30 corresponds to the number of battery string units 10.

[0055] In the back-contact battery module 100 and photovoltaic system 1000 of this application embodiment, multiple battery string units 10 are connected in series via busbars 20. Each battery string unit 10 includes three battery strings 11, and the cells 111 in the battery strings 11 are one-third sliced ​​cells. At least one of the multiple busbars 20 is disposed on the back side of the cells 111 in the battery strings 11. Each battery string unit 10 is provided with a bypass diode 30 in parallel, and the bypass diode 30 is connected in parallel to the battery string unit 10 via a connecting line 40. In this way, the cells 111 in the battery strings 11 are one-third sliced ​​cells. By connecting the battery strings 11 in parallel within the battery string unit 10 and connecting the battery string units 10 in series with each other, the power loss of the module can be reduced while keeping the final output voltage and current of the module essentially the same as that of a conventional module. In addition, since the battery strings 11 in the battery string unit 10 are connected in parallel, the risk of hot spots can be effectively reduced. Furthermore, since the cells 111 are one-third sliced ​​cells, their size is relatively small, which can enhance the resistance to microcracks and reduce the risk of microcracks. Meanwhile, at least one of the multiple busbars 20 is disposed on the back of the battery cell 111, which can hide the busbar 20, thereby increasing the power generation per unit area of ​​the back contact battery module 100 and also improving the aesthetics of the back contact battery module 100.

[0056] Specifically, in this application, the back contact battery assembly 100 further includes a front panel, a front adhesive film, a rear adhesive film, and a back side. The back contact battery assembly 100 can be formed by encapsulating the front panel, the front adhesive film, the rear adhesive film, and the back side together. In the embodiments of this application, the battery cell 111 can be a back contact battery cell with a main grid or a back contact battery cell without a main grid; no specific limitation is made here.

[0057] Please refer to Figures 2 and 4. In some embodiments of this application, multiple battery string units 10 are arranged in parallel along a first direction, and battery strings 11 in battery string units 10 are also arranged in parallel along the first direction. Multiple battery cells 111 in battery strings 11 are connected in series along a second direction, and the second direction intersects the first direction.

[0058] Specifically, as shown in Figures 2 and 4, in some embodiments, the number of battery string units 10 can be three. These three battery string units 10 are arranged in parallel along a first direction and connected in series via a busbar 20. The battery strings 11 within each battery string unit 10 are also arranged in parallel along the first direction. Multiple battery cells 111 within each battery string 11 are connected in series sequentially along a second direction, which intersects the first direction. Thus, the back-contact battery assembly 100 includes three battery string units 10, each battery string unit 10 comprising three parallel battery strings 11. The battery cells 111 within each battery string 11 are one-third sliced ​​batteries, ensuring that the final output voltage and current of the back-contact battery assembly 100 are essentially the same as those of a conventional assembly.

[0059] Of course, in some possible embodiments, the number of battery string units 10 in the back contact battery assembly 100 may be greater than three, and no specific limitation is made here. In the following description, the number of battery string units 10 shall be three.

[0060] Specifically, in this application, the first direction may be the longitudinal direction of the back contact battery assembly 100, and the second direction may be the transverse direction of the back contact battery assembly 100, and the two are perpendicular to each other.

[0061] In the battery string unit 10, the three battery strings 11 have the same polarity orientation; that is, the positive terminals of the three battery strings 11 are located on one side of the second direction, and the negative terminals of the three battery strings 11 are located on the other side of the second direction. The positive terminals of the three battery strings 11 are connected to the busbar 20 at one end of the battery string unit 10, and the negative terminals of the three battery strings 11 are connected to the busbar 20 at the other end of the battery string unit 10. All busbars 20 extend along the first direction.

[0062] Referring to Figures 2 and 4, in the back-contact battery assembly 100, the positive and negative terminals of two adjacent battery string units 10 are opposite. That is, in this application, in the second direction, the busbar 20 at one end of the battery string unit 10 is connected to the positive terminal of the battery string unit 10 (i.e., the positive terminal of all battery strings 11 in the battery string unit 10), and the busbar 20 at the other end of the battery string unit 10 is connected to the negative terminal of the battery string unit 10 (i.e., the negative terminal of all battery strings 11 in the battery string unit 10), with the positive and negative terminals of two adjacent battery string units 10 being opposite. In two adjacent battery string units 10, the positive terminal of one battery string unit 10 and the negative terminal of the other battery string unit 10 are located on the same side, and the busbar 20 connected to the positive terminal of one battery string unit 10 is connected to the busbar 20 connected to the negative terminal of the other battery string unit 10 to connect the two adjacent battery string units 10 in series.

[0063] As shown in Figures 2 and 4, in some embodiments, among the three battery string units 10 arranged from top to bottom in the first direction, the left side of the first battery string unit 10 in the second direction can be the positive terminal and the right side can be the negative terminal; the left side of the second battery string unit 10 can be the negative terminal and the right side can be the positive terminal; and the left side of the third battery string unit 10 in the second direction can be the positive terminal and the right side can be the negative terminal. In this case, the busbar 20 on the left side of the first battery string unit 10 in the second direction is the positive output terminal of the back-contact battery assembly 100, and the busbar 20 on the right side of the third battery string unit 10 in the second direction is the negative output terminal of the back-contact battery assembly 100. The busbar 20 on the right side of the first battery string unit 10 in the second direction is connected to the busbar 20 on the right side of the second battery string unit 10 in the second direction to realize the series connection of the two. The busbar 20 on the left side of the second battery string unit 10 in the second direction is connected to the busbar 20 on the left side of the third battery string unit 10 in the second direction to realize the series connection of the two. In this way, the three battery string units 10 in the back contact battery assembly 100 can be connected in series sequentially.

[0064] Of course, in some embodiments, among the three battery string units 10 from top to bottom in the first direction, the first battery string unit 10 may have its left side as the negative terminal and its right side as the positive terminal in the second direction, the second battery string unit 10 may have its left side as the positive terminal and its right side as the negative terminal in the second direction, and the third battery string unit 10 may have its left side as the negative terminal and its right side as the positive terminal in the second direction. In this case, the busbar 20 on the left side of the first battery string unit 10 in the second direction is the negative output terminal of the back contact battery assembly 100, and the busbar 20 on the right side of the third battery string unit 10 in the second direction is the positive output terminal of the back contact battery assembly 100.

[0065] Please refer to Figures 2 and 4. In some embodiments, in two adjacent battery strings 11, the busbar 20 connected to the positive electrode on one battery string unit 10 is integrally formed with the busbar 20 connected to the negative electrode on the other battery string unit 10.

[0066] In this way, a longer busbar 20 can be used to connect two adjacent battery string units 10 in series, without the need to set up two separate busbars 20 and then weld them together, which makes the structure simpler.

[0067] Specifically, as shown in Figures 2 and 4, in the first direction, the busbar 20 on the right side of the first battery string unit 10 and the busbar 20 on the right side of the second battery string unit 10 are integrally formed as a single busbar, and the busbar 20 on the left side of the second battery string unit 10 and the busbar 20 on the left side of the third battery string unit 10 are integrally formed as a single busbar. In this way, the series connection between each battery string unit 10 in the back contact battery assembly 100 can be realized.

[0068] Please refer to Figures 2 and 3. In some embodiments, the battery strings 11 in the battery string unit 10 all include first battery cells 1111 located at both ends of the battery string 11, and the busbar 20 is disposed on the back of the first battery cells 1111.

[0069] On the battery string unit 10, one busbar 20 is disposed on the back of one of the first battery cells 1111 and is connected to the positive electrode solder strip 112 on the first battery cell 1111 and is insulated from the negative electrode solder strip 113 on the first battery cell 1111. Another busbar 20 is disposed on the back of another first battery cell 1111 and is connected to the negative electrode solder strip 113 on the first battery cell 1111 and is insulated from the positive electrode solder strip 112 on the first battery cell 1111.

[0070] In this way, the busbars 20 at both ends of the battery string unit 10 can be hidden behind the first solar cells 1111 located at both ends of the battery string 11, thereby achieving the concealment of the busbars 20, increasing the power generation per unit area of ​​the module, improving the module efficiency, and reducing the module area while achieving the same power generation. At the same time, by insulating one busbar 20 with the negative electrode solder strip 113 of the first solar cell 1111 and the other busbar 20 with the positive electrode solder strip 112 of the first solar cell 1111, short circuits between the busbars 20 and solder strips of different polarities can be avoided.

[0071] Specifically, in such an embodiment, it is preferable that all the busbars 20 are disposed on the back side of the first battery cell 1111 of the back contact battery assembly 100, or only some of the busbars 20 are disposed on the back side of the first battery cell 1111, while the remaining busbars 20 are disposed on the outside side of the first battery cell 1111. No specific limitation is made here.

[0072] Further, referring to Figures 2 and 3, in some embodiments, on the battery string unit 10, a first insulating layer 50 is provided between one of the busbars 20 and the negative electrode solder strip 113 on the first battery cell 1111 (the first battery cell 1111 on the left side of the first battery string unit 10 in Figure 2), and a second insulating layer 60 is provided between the other busbar 20 and the positive electrode solder strip 112 on the first battery cell 1111 (the first battery cell 1111 on the right side of the first battery string unit 10 in Figure 2).

[0073] Thus, by setting the first insulating layer 50 and the second insulating layer 60, the insulation performance between the busbar 20 and the solder strip of opposite polarity can be guaranteed, thereby improving the reliability and stability of the back contact battery assembly 100.

[0074] Specifically, in such an embodiment, a first insulating layer 50 can be disposed below one of the busbars 20 of the battery string unit 10. A hole is made in the first insulating layer 50 to expose the positive electrode solder strip 112 on the first battery cell 1111, thereby enabling the welding of the positive electrode solder strip 112 on the first battery cell 1111 to the busbar 20. A second insulating layer 60 can be disposed below the other busbar 20 of the battery string unit 10. A hole is made in the second insulating layer 60 to expose the negative electrode solder strip 113 on the first battery cell 1111, thereby enabling the welding of the negative electrode solder strip 113 on the first battery cell 1111 to the busbar 20. Of course, in some embodiments, the first insulating layer 50 can also be composed of multiple discontinuous portions, each discontinuous portion corresponding to the negative electrode solder strip on the first battery cell 1111. The second insulating layer 60 can also be composed of multiple discontinuous portions, each discontinuous portion corresponding to the positive electrode solder strip on the first battery cell 1111.

[0075] In some embodiments, the length of the first insulating layer 50 in the second direction (i.e., the width of the first insulating layer 50) is greater than or equal to the length of the busbar 20 in the second direction (i.e., the width of the busbar 20).

[0076] In this way, the busbar 20 on the first insulating layer 50 will not come into electrical contact with the welding strip of opposite polarity, thus improving the electrical isolation effect and insulation performance.

[0077] In some embodiments, the length of the second insulating layer 60 in the second direction (i.e., the width of the second insulating layer 60) is greater than or equal to the length of the busbar 20 in the second direction (i.e., the width of the busbar 20).

[0078] In this way, the busbar 20 on the second insulation layer 60 will not come into electrical contact with the solder strip of opposite polarity, thus improving the electrical isolation effect and insulation performance.

[0079] Please refer to Figures 4 and 5. In some other embodiments, the battery string 11 in the battery string unit 10 may include a first battery cell 1111 located at both ends of the battery string 11 and a second battery cell 1112 adjacent to the first battery cell 1111. A busbar 20 is disposed on the second battery cell 1112 and a first insulating strip 70 is provided between the busbar 20 and the second battery cell 1112.

[0080] Thus, by setting the busbar 20 on the second battery cell 1112, and then using a whole first insulating strip 70 to achieve insulation between the busbar 20 and the positive electrode solder strip 112 and the negative electrode solder strip 113 on the second battery cell 1112, without the need to make holes in the first insulating strip 70, the manufacturing process can be simplified and the process difficulty reduced.

[0081] Specifically, as shown in Figures 4 and 5, in this embodiment, in the battery string unit 10, the busbar 20 located on one of the second battery cells 1112 is insulated from the positive electrode solder strip 112 and the negative electrode solder strip 113 on the second battery cell 1112 by a first insulating strip 70, and the busbar 20 is connected to the positive electrode solder strip 112 or the negative electrode solder strip 113 on the first battery cell 1111 adjacent to the second battery cell 1112, and the busbar 20 located on the other second battery cell 1112... Busbar 20 is insulated from the positive electrode solder strip 112 and negative electrode solder strip 113 on the second battery cell 1112 by a first insulating strip 70. Busbar 20 is connected to the positive electrode solder strip 112 or negative electrode solder strip 113 on the first battery cell 1111 adjacent to the second battery cell 1112. One of the two busbars 20 is connected to the positive electrode solder strip 112 on one of the first battery cells 1111, and the other is connected to the negative electrode solder strip 113 on the other first battery cell 1111.

[0082] Of course, in some embodiments, the busbar 20 may also span both the first battery cell 1111 and the second battery cell 1112. The busbar 20 is disposed between the first battery cell 1111 and the second battery cell 1112, with a portion located on the first battery cell 1111 and a portion located on the second battery cell 1112. That is, the busbar 20 has overlapping portions with both the first battery cell 1111 and the second battery cell 1112. In this case, a first insulating strip 70 is disposed between the busbar 20 and the first battery cell 1111 and the second battery cell 1112. In other words, in this case, a portion of the first insulating strip 70 is located on the first battery cell 1111 and a portion is located on the second battery cell 1112.

[0083] In some embodiments, the length of the first insulating strip 70 in the second direction (i.e., the width of the first insulating strip 70) is greater than or equal to the length of the busbar 20 in the second direction (i.e., the width of the busbar 20).

[0084] In this way, the busbar 20 on the first insulating strip 70 will not come into electrical contact with the welding strip of opposite polarity, thus improving the electrical isolation effect and insulation performance.

[0085] In some embodiments, the resistance per unit length of the connecting line 40 is less than or equal to the resistance per unit length of the busbar 20. That is, per unit length, the resistance of the connecting line 40 is less than or equal to the resistance of the busbar 20.

[0086] In this way, when the bypass diode is turned on, the transmission loss during the transmission process can be guaranteed to be not too large.

[0087] Please refer to Figure 6 (Figure 6 does not show the positive electrode solder strip 112, negative electrode solder strip 113, first insulating layer 50, and second insulating layer 60). In some embodiments, in the battery string 11, two adjacent battery cells 111 partially overlap. That is, in the battery string 11, two adjacent battery cells 111 arranged in series along the second direction have an overlapping portion in the second direction.

[0088] In this way, the spacing between the cells 111 within the battery string 11 can be eliminated, thereby increasing the unit light-receiving area of ​​the back-contact battery assembly 100.

[0089] In such an embodiment, the length of overlap between two adjacent battery cells 111 in the second direction is 0.2mm-0.5mm, for example, any value between 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm or 0.2mm-0.5mm.

[0090] Referring to Figure 7 (Figure 7 does not show the positive electrode solder strip 112, negative electrode solder strip 113, first insulating layer 50, and second insulating layer 60), in some embodiments, two adjacent battery strings 11 in the battery string unit 10 at least partially overlap. That is, in the battery string unit 10, two adjacent battery strings 11 arranged along the first direction have an overlapping portion in the first direction.

[0091] In this way, the spacing between battery strings 11 within the battery string unit 10 can be eliminated, thereby increasing the unit light-receiving area of ​​the back contact battery assembly 100.

[0092] In such an embodiment, the overlap length of two adjacent battery strings 11 in the first direction is 0.2mm-0.5mm, for example, any value between 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm or 0.2mm-0.5mm.

[0093] Referring to Figure 8 (Figure 8 does not show the positive electrode solder strip 112, negative electrode solder strip 113, first insulating layer 50, and second insulating layer 60), in some embodiments, in two adjacent battery string units 10, the two adjacent battery strings 11 at least partially overlap. That is, in two adjacent battery string units 10, the lowermost battery string 11 of one battery string unit 10 and the uppermost battery string 11 of the other battery string unit 10 partially overlap in a first direction.

[0094] In this way, the gap between two adjacent battery string units 10 can be eliminated, thereby increasing the unit light-receiving area of ​​the back contact battery assembly 100.

[0095] It is easy to understand that, as shown in Figure 8, when two adjacent battery strings 11 within the battery string unit 10 partially overlap and there is partial overlap between battery string units 10 and battery string units 10, the busbar 20 can be completely hidden when it is located on the back of the battery cell 111.

[0096] Referring to Figure 8, in some embodiments, at least one connecting wire 40 is located on the back of the battery string 11, and a second insulating strip 80 is provided between the connecting wire 40 and the battery string 11.

[0097] In this way, at least one connecting wire 40 can be hidden, further improving the power generation per unit area of ​​the back contact battery module 100. At the same time, the setting of the second insulating strip 80 can also prevent the connecting wire 40 from making conductive contact with the solder strip on the back of the battery cell 111 of the battery string 11, thus avoiding leakage and improving the reliability and stability of the module.

[0098] Specifically, as shown in Figure 8, in the embodiment shown in Figure 8, all connecting wires 40 are disposed on the back of the battery string 11, thereby concealing all connecting wires 40 and maximizing the power generation per unit area of ​​the module. Of course, it is understood that in some embodiments, only some connecting wires 40 may be disposed on the back of the battery string 11, and this is not a limitation here.

[0099] It is easy to understand that when the battery cells 111 in the battery string 11 partially overlap in the second direction to eliminate the spacing between cells in the string, the connecting line 40 can be completely hidden when it is located on the back of the battery cells 111.

[0100] In some embodiments, the length of the second insulating strip 80 in the first direction (i.e., the width of the second insulating strip 80) is less than or equal to the length of the connecting line 40 in the first direction (i.e., the width of the connecting line 40).

[0101] In this way, the connecting wire 40 on the second insulating strip 80 will not make electrical contact with the battery cell 111, thus improving the electrical isolation effect and insulation performance.

[0102] Referring to Figures 2, 4, 6, and 7, in some embodiments, the connecting line 40 and the diode connected in parallel with the battery string unit 10 may be located outside the battery string unit 10. This avoids the connecting line 40 and the diode interfering with the arrangement of the individual battery strings 11 in the battery string unit 10.

[0103] Of course, in some embodiments, the connecting line 40 and the bypass diode 30 connected in parallel with the battery string unit 10 may be located between two adjacent battery strings 11 in the battery string 11.

[0104] Please refer to Figure 9 (Figure 9 does not show the positive electrode solder strip 112, the negative electrode solder strip 113, the first insulating layer 50, and the second insulating layer 60). In some embodiments, among the plurality of bypass diodes 30, at least two bypass diodes 30 share the same connection line 40.

[0105] Thus, among the multiple bypass diodes 30, two bypass diodes 30 share a single connection line 40, which can save costs.

[0106] In some embodiments, the resistance per unit length of the connection line 40 shared by the two bypass diodes 30 is less than or equal to the resistance per unit length of the other connection lines 40.

[0107] Thus, when connecting two bypass diodes 30 to the connecting line 40, it can be ensured that the transmission loss of the bypass diodes 30 will not be too large when they are working.

[0108] In the description of this specification, the use of terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the embodiments or examples, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0109] Furthermore, the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-contact battery assembly, characterized in that, include: Multiple battery string units connected in series, each battery string unit including three battery strings connected in parallel, each battery string including multiple battery cells connected in series, the multiple battery cells being connected in series via positive and negative electrode solder strips, the battery cells being sliced ​​batteries formed by cutting or splitting back-contact battery cells into three equal parts; multiple busbars, each battery string unit having a busbar at both ends, the multiple battery string units being connected in series via the busbars, at least one of the busbars being located on the back side of the battery cells in the battery string; and multiple bypass diodes, each battery string unit having a bypass diode connected in parallel, the bypass diodes being connected in parallel to the battery string unit via connecting wires.

2. The back contact battery assembly according to claim 1, characterized in that, Multiple battery string units are arranged in parallel along a first direction, and the battery strings in the battery string units are also arranged in parallel along the first direction. Multiple battery cells in the battery string are connected in series along a second direction, which intersects with the first direction.

3. The back contact battery assembly according to claim 2, characterized in that, The busbar at one end of the battery string unit is connected to the positive terminal of the battery string unit, and the busbar at the other end is connected to the negative terminal of the battery string unit. In two adjacent battery string units, the busbar connected to the positive terminal of one battery string unit is connected to the busbar connected to the negative terminal of the other battery string unit, so as to connect the two adjacent battery string units in series.

4. The back contact battery assembly according to claim 2, characterized in that, The busbar connected to the positive terminal on one of the battery string units is integrally formed with the busbar connected to the negative terminal on the other battery string unit.

5. The back contact battery assembly according to claim 2, characterized in that, Each battery string in the battery string unit includes a first battery cell located at both ends of the battery string, and the busbar is disposed on the back of the first battery cell; on the battery string unit, one of the busbars is disposed on the back of one of the first battery cells and is connected to the positive electrode solder strip on the first battery cell and insulated from the negative electrode solder strip on the first battery cell, and the other busbar is disposed on the back of another first battery cell and is connected to the negative electrode solder strip on the first battery cell and insulated from the positive electrode solder strip on the first battery cell.

6. The back contact battery assembly according to claim 5, characterized in that, On the battery string unit, a first insulating layer is provided between one of the busbars and the negative electrode solder strip on the first battery cell, and a second insulating layer is provided between the other busbar and the positive electrode solder strip on the first battery cell.

7. The back contact battery assembly according to claim 6, characterized in that, The length of the first insulating layer in the second direction is greater than or equal to the length of the busbar in the second direction; and / or, the length of the second insulating layer in the second direction is greater than or equal to the length of the busbar in the second direction.

8. The back contact battery assembly according to claim 2, characterized in that, Each battery string in the battery string unit includes a first battery cell located at both ends of the battery string and a second battery cell adjacent to the first battery cell; the busbar is disposed on the back of the second battery cell, and a first insulating strip is provided between the busbar and the second battery cell; or the busbar has an overlapping portion with both the first battery cell and the second battery cell, and a first insulating strip is provided between the busbar and the first battery cell and the second battery cell.

9. The back contact battery assembly according to claim 8, characterized in that, The length of the first insulating strip in the second direction is greater than or equal to the length of the busbar in the second direction.

10. The back contact battery assembly according to claim 2, characterized in that, At least one of the connecting wires is located on the back of the battery string, and a second insulating strip is provided between the connecting wire and the battery cell.

11. The back contact battery assembly according to claim 10, characterized in that, The length of the second insulating strip in the first direction is greater than or equal to the length of the connecting wire in the first direction.

12. The back contact battery assembly according to claim 1, characterized in that, The resistance per unit length of the connecting wire is less than or equal to the resistance per unit length of the busbar.

13. The back contact battery assembly according to claim 1, characterized in that, In the battery string, two adjacent battery cells partially overlap; and / or two adjacent battery strings in the battery string unit partially overlap; and / or two adjacent battery strings in two adjacent battery string units partially overlap.

14. The back contact battery assembly according to claim 1, characterized in that, The connecting line and the bypass diode, which are connected in parallel with the battery string unit, are located between two adjacent battery strings.

15. The back contact battery assembly according to claim 1, characterized in that, In the plurality of bypass diodes, at least two of the bypass diodes share the same connection line.

16. The back contact battery assembly according to claim 15, characterized in that, The resistance per unit length of the connection line shared by the two bypass diodes is less than or equal to the resistance per unit length of the other connection lines.

17. A photovoltaic system, characterized in that, Includes the back contact battery assembly as described in any one of claims 1-16.

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