Back contact battery assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a back contact cell module and a photovoltaic system. The back contact battery assembly comprises a battery string, a welding strip, a conductive connection structure and an insulation structure, a first battery piece and a second battery piece are distributed along a first direction, the first battery piece and the second battery piece are at least partially stacked together, a first grid line and a second grid line extend along a second direction and are alternately arranged along the first direction, and the first grid line and the second grid line are arranged alternately along the second direction. The welding strip is arranged on the back face of the first cell piece and extends in the first direction, a containing space is formed between the side, close to the second cell piece, of the first cell piece and the welding strip, and the conductive connecting structure is at least partially laid in the containing space and is connected with the first grid line in the containing space and the welding strip. Therefore, the welding strip can be connected with the first grid line in the accommodating space through the conductive connecting structure, so that the current in the accommodating space can be collected, and the power generation efficiency of the back contact battery assembly is further improved.

Description

Technical Field

[0001] This application belongs to the technical field of solar cells, and particularly relates to a back-contact battery module and a photovoltaic system. Background Art

[0002] Currently, a back-contact battery refers to a solar cell in which the light-facing surface of the battery cell has no electrodes, and the positive and negative electrodes are both arranged on the backlight side of the battery cell, so as to reduce the shielding of the battery cell by the electrodes, increase the short-circuit current of the battery cell, and improve the energy conversion efficiency of the battery cell. In the related art, multiple back-contact batteries are stacked edge to edge, which can increase the light-receiving area of the battery. However, the stacked back-contact batteries will cause the current at the edge position of one of the back-contact batteries to be unable to be collected, resulting in a decrease in the power generation efficiency of the battery. Summary of the Utility Model

[0003] The embodiments of this application provide a back-contact battery module and a photovoltaic system, aiming to solve the problem that the current at the edge position cannot be collected when a photovoltaic cell uses a stacked structure.

[0004] A back-contact battery module provided by an embodiment of this application includes a battery string, a solder ribbon, a conductive connection structure, and an insulating structure. The battery string includes adjacent first battery cells and second battery cells. The first battery cells and the second battery cells are arranged along a first direction. The first battery cells and the second battery cells are at least partially stacked together. First grid lines and second grid lines are formed on the back surfaces of the first battery cells and the second battery cells. The first grid lines and the second grid lines extend along a second direction and are alternately arranged along the first direction. The first grid lines and the second grid lines have opposite polarities. The solder ribbon is arranged on the back surface of the first battery cell and extends along the first direction. A receiving space is formed between the side of the first battery cell close to the second battery cell and the solder ribbon. The conductive connection structure is at least partially laid in the receiving space and connects the first grid lines and the solder ribbon in the receiving space. The insulating structure covers the second grid lines. The insulating structure is arranged in the receiving space and is located between the second grid lines and the solder ribbon.

[0005] Furthermore, the solder ribbon includes a first solder ribbon. The first solder ribbon extends along the first direction and connects the back surfaces of the first battery cell and the second battery cell. A receiving space is formed between the side of the first battery cell close to the second battery cell and the first solder ribbon.

[0006] Further, when at least a part of the back surface of the first solar cell and the front surface of the second solar cell are laminated together, the accommodating space is formed on one side of the back surface of the first solar cell close to the second solar cell. The solder ribbon further includes a second solder ribbon and a third solder ribbon. The second solder ribbon is disposed on the back surface of the first solar cell and at least partially extends into the back surface of the second solar cell, and the third solder ribbon is located on the back surface of the second solar cell.

[0007] Further, the back contact battery assembly further includes a bus bar, and the bus bar is disposed on the back surface of the second solar cell;

[0008] The bus bar is connected to the second solder ribbon and is located on a side of the second solder ribbon away from the second solar cell;

[0009] The bus bar is connected to the second solder ribbon and is located on a side of the second solder ribbon close to the second solar cell.

[0010] Further, when at least a part of the front surface of the first solar cell and the back surface of the second solar cell are laminated together, the accommodating space is formed on one side of the back surface of the first solar cell close to the second solar cell. The solder ribbon further includes a second solder ribbon and a third solder ribbon. The second solder ribbon is disposed on the back surface of the first solar cell and at least partially extends into the back surface of the second solar cell, and the third solder ribbon is located on the back surface of the second solar cell.

[0011] Further, the back contact battery assembly further includes a bus bar, and the bus bar is disposed on the back surface of the first solar cell;

[0012] The bus bar is connected to the second solder ribbon and is located on a side of the second solder ribbon away from the first solar cell;

[0013] The bus bar is connected to the second solder ribbon and is located on a side of the second solder ribbon close to the first solar cell.

[0014] Further, the insulating structure is prepared by laying or coating.

[0015] Further, the conductive connection structure is solder paste, conductive adhesive or other metal conductive materials.

[0016] Further, the length of the conductive connection structure along the first direction is greater than 6 mm.

[0017] Further, the thickness of the conductive connection structure along the third direction is 30 μm - 300 μm, wherein the third direction is perpendicular to the first direction and the second direction.

[0018] Further, in the second direction, the width of the solder ribbon is greater than the width of the conductive connection structure.

[0019] Further, in the second direction, the width of the insulating structure is greater than the width of the conductive connection structure.

[0020] Further, the thickness of the insulating structure is 25 μm - 40 μm.

[0021] Further, an inclined surface is formed on a side of the conductive connection structure away from the first cell, and the inclined surface is connected to the solder ribbon.

[0022] Further, the back contact cell assembly further includes an insulating layer disposed between the bus bar and the third solder ribbon.

[0023] The photovoltaic system provided by the embodiment of the present application includes the back contact cell assembly described in any one of the above embodiments.

[0024] In the back contact cell assembly and the photovoltaic system according to the embodiment of the present application, the back contact cell assembly includes a cell string, a solder ribbon, a conductive connection structure, and an insulating structure. The cell string includes adjacent first and second cells. The first and second cells are arranged along a first direction, and at least partially overlap each other. First grid lines and second grid lines are formed on the back surfaces of the first and second cells. The first grid lines and the second grid lines extend along a second direction and are alternately arranged along the first direction. The first grid lines and the second grid lines have opposite polarities. The solder ribbon is disposed on the back surface of the first cell and extends along the first direction. A receiving space is formed between a side of the first cell close to the second cell and the solder ribbon. The conductive connection structure is at least partially laid in the receiving space and connects the first grid line and the solder ribbon in the receiving space. The insulating structure covers the second grid line and is disposed in the receiving space between the second grid line and the solder ribbon. In this way, the solder ribbon can be connected to the first grid line in the receiving space through the conductive connection structure, so that the current in the receiving space can be collected, thereby improving the power generation efficiency of the back contact cell assembly. At the same time, the insulating structure can be disposed between the second grid line and the conductive connection structure to avoid short - circuit problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a partial plan structure schematic diagram of a back contact cell according to an embodiment of the present application;

[0026] Figure 2 is a partial cross - section structure schematic diagram of a back contact cell according to an embodiment of the present application;

[0027] Figure 3 is another partial cross - section schematic diagram of a back contact cell according to an embodiment of the present application;

[0028] Figure 4 is an enlarged schematic diagram of A in one embodiment of the present application; Figure 3 in the middle;

[0029] Figure 5 is another partial cross-sectional schematic diagram of the back-contact battery in one embodiment of the present application;

[0030] Figure 6 is another partial cross-sectional schematic diagram of the back-contact battery in one embodiment of the present application;

[0031] Figure 7 is another partial cross-sectional schematic diagram of the back-contact battery in one embodiment of the present application;

[0032] Figure 8 is another partial cross-sectional schematic diagram of the back-contact battery in one embodiment of the present application;

[0033] Figure 9 is a schematic diagram of the module structure of the back-contact battery in one embodiment of the present application;

[0034] Figure 10 is a schematic diagram of the module structure of the photovoltaic system in one embodiment of the present application.

[0035] Description of main element symbols:

[0036] Back-contact battery assembly 100, first cell 10, front surface 11, back surface 12, first grid line 121, second grid line 122, second cell 20, solder strip 30, accommodation space 31, first solder strip 32, second solder strip 33, third solder strip 34, conductive connection structure 40, inclined surface 41, insulating structure 50, bus bar 60, insulating layer 70, cell string 200, photovoltaic system 300. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as a limitation to 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.

[0038] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application 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. Therefore, it should not be construed as a limitation to the present application.

[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying 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 application, "a plurality of" means two or more unless otherwise specifically defined.

[0040] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" 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 connection capable of mutual communication; 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 application can be understood according to specific circumstances.

[0041] In the present application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the 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 additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means 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 that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0042] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application 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.

[0043] In the related art, a solar cell is a semiconductor device that directly converts the energy of sunlight into electrical energy. The solar cell utilizes the photovoltaic effect to excite electrons by absorbing photons and exports these electrons through a built-in electric field to generate current. A back-contact cell refers to a solar cell in which the light-facing surface of the cell has no electrodes, and both the positive and negative electrodes are disposed on the backlight side of the cell, so that the shielding of the electrodes from the cell can be reduced, the short-circuit current of the cell can be increased, and the energy conversion efficiency of the cell can be improved. In the prior art, in order to obtain a larger light-receiving area and eliminate the gap between different cells, the edge portions of two adjacent cells are superimposed together. However, this will cause the fine grids located at the edge portions to be unable to be connected by the solder tape, and the current at the edge positions cannot be collected, resulting in a decrease in the power generation efficiency of the cell. In the embodiment of the present application, a conductive connection structure is provided at the edge portion to connect the solder tape and the corresponding fine grid, and then all the current of the cell is collected to improve the power generation efficiency.

[0044] Embodiment 1

[0045] Please refer to Figures 1 to 4, a back-contact battery assembly 100 provided by an embodiment of the present application, the back-contact battery assembly 100 includes a battery string 200, a solder ribbon 30, a conductive connection structure 40, and an insulating structure 50. The battery string 200 includes adjacent first battery cells 10 and second battery cells 20. The first battery cells 10 and the second battery cells 20 are arranged along a first direction. At least a part of the first battery cells 10 and the second battery cells 20 are stacked together. First grid lines 121 and second grid lines 122 are formed on the back surfaces 12 of the first battery cells 10 and the second battery cells 20. The first grid lines 121 and the second grid lines 122 extend along a second direction and are alternately arranged along the first direction. The first grid lines 121 and the second grid lines 122 have opposite polarities. The solder ribbon 30 is arranged on the back surface 12 of the first battery cell 10 and extends along the first direction. A receiving space 31 is formed between one side of the first battery cell 10 close to the second battery cell 20 and the solder ribbon 30. The conductive connection structure 40 is at least partially laid in the receiving space 31 and connects the first grid line 121 and the solder ribbon 30 in the receiving space 31. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is arranged in the receiving space 31 and is located between the second grid line 122 and the solder ribbon 30.

[0046] Further, the solder ribbon 30 includes a first solder ribbon 31. The first solder ribbon 31 extends along the first direction and connects the back surfaces 12 of the first battery cell 10 and the second battery cell 20. A receiving space 31 is formed between one side of the first battery cell 10 close to the second battery cell 20 and the first solder ribbon 32.

[0047] In the back-contact battery assembly 100 according to the embodiment of the present application, the back-contact battery assembly 100 includes a battery string 200, a solder strip 30, a conductive connection structure 40, and an insulating structure 50. The battery string 200 includes adjacent first battery cells 10 and second battery cells 20. The first battery cells 10 and the second battery cells 20 are arranged along a first direction. The first battery cells 10 and the second battery cells 20 are at least partially stacked together. First grid lines 121 and second grid lines 122 are formed on the back surfaces 12 of the first battery cells 10 and the second battery cells 20. The first grid lines 121 and the second grid lines 122 extend along a second direction and are alternately arranged along the first direction. The first grid lines 121 and the second grid lines 122 have opposite polarities. The solder strip 30 is arranged on the back surface 12 of the first battery cell 10 and extends along the first direction. A receiving space 31 is formed between one side of the first battery cell 10 close to the second battery cell 20 and the solder strip 30. The conductive connection structure 40 is at least partially laid in the receiving space 31 and connects the first grid line 121 in the receiving space 31 and the solder strip 30. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is arranged in the receiving space 31 and is located between the second grid line 122 and the solder strip 30. Thus, the solder strip 30 can be connected to the first grid line 121 in the receiving space 31 through the conductive connection structure 40, so that the current in the receiving space 31 can be collected, thereby improving the power generation efficiency of the back-contact battery assembly 100. At the same time, the insulating structure 50 can be arranged between the second grid line 122 and the conductive connection structure 40 to avoid the problem of short circuit.

[0048] In this embodiment, the front surface 11 of the battery cell is used to receive light. The back surface 12 of the battery cell includes a plurality of alternately arranged first doping layers and second doping layers (not shown in the figure). The first grid line 121 is arranged on the first doping layer, and the second grid line 122 is arranged on the second doping layer. The first grid lines 121 and the second grid lines 122 extend along the second direction and are alternately arranged along the first direction. At the same time, the first doping layers and the second doping layers also extend along the second direction and are alternately arranged along the first direction to form a photocurrent.

[0049] In the embodiment of the present application, there is no main grid on the back surface 12 of the battery cell. The first grid line 121 and the second grid line 122 can directly achieve current convergence through the welding tape 30. The welding tape 30 includes a first welding tape 32 and a second welding tape 33. The first welding tape 32 and the second welding tape 33 extend along the first direction and are alternately distributed along the second direction. At the same time, the first grid line 121 and the second grid line 122 have opposite polarities. The first welding tape 32 can connect the first grid line 121 of the first battery cell 10 and the second grid line 122 of the second battery cell 20 to connect the first battery cell 10 and the second battery cell 20 in series. At the same time, there is another second welding tape 33 that connects the first grid line 121 of the second battery cell 20 and the bus bar 60. In the embodiment of the present application, the relative position between the bus bar 60 and the second welding tape 33 is not limited to meet various requirements. At this time, an insulating structure 50 is provided between the first welding tape 32 and the second grid line 122 of the first battery cell 10 to achieve insulation, and an insulating structure 50 is provided between the first welding tape 32 and the first grid line 121 of the second battery cell 20 to achieve insulation.

[0050] In the embodiment of the present application, the first battery cell 10 and the second battery cell 20 are at least partially stacked together to avoid wasting the component space and increasing the cost caused by too large a spacing. A receiving space 31 is formed between the side of the first battery cell 10 close to the second battery cell 20 and the welding tape 30. The conductive connection structure 40 is at least partially laid in the receiving space 31 and connects the first grid line 121 and the welding tape 30 in the receiving space 31. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is provided in the receiving space 31 and is located between the second grid line 122 and the welding tape 30. In this way, the current generated by the first doping layer corresponding to the first grid line 121 inside the receiving space 31 can also be diverted by the welding tape 30 to enable all the doping layers of the battery cell to generate electric energy, thereby improving the power generation efficiency of the back-contact battery module 100. Of course, in some embodiments, the conductive connection structure 40 fills the entire receiving space 31, and thus can connect all the first grid lines 121 inside the receiving space 31 and conduct them out through the welding tape 30.

[0051] Specifically, when the first grid line 121 is a positive grid line and the second grid line 122 is a negative grid line, the first welding tape 32 can straddle the first battery cell 10 and the second battery cell 20. The first welding tape 32 can connect the first grid line 121 of the first battery cell 10 and the second grid line 122 of the second battery cell 20. That is to say, the first welding tape 32 can connect the positive grid line of the first battery cell 10 and the negative grid line of the second battery cell 20. At this time, the insulating structure 50 can be provided on the second grid line 122 of the first battery cell 10 and on the first grid line 121 of the second battery cell 20, so as to realize the series connection of the first battery cell 10 and the second battery cell 20.

[0052] Further, the battery string 200 may further include a current collecting structure to collect the currents of multiple battery cells. The current collecting structure may be connected to the solder tapes 30 of the same polarity to form a loop with the battery string 200 to export the current energy. Multiple battery cells may be connected in series through the solder tapes 30 to form a battery string 200 distributed in the first direction. Of course, in some embodiments, the solder tape 30 at the end of the battery string 200 may be connected to only the grid line on one battery cell and extend relative to the battery cell to connect to structures such as the bus bar 60. In addition, in the embodiments of the present application, the form of the current collecting structure is not limited to meet different requirements. For example, the current collecting structure may be a conductive material such as a wire, a bus bar 60, or a conductive tape.

[0053] It can be understood that "first" and "second" in the first battery cell 10 and the second battery cell 20 are relative concepts, indicating that the two back-contact battery cells are different. For example, in Figure 1 the example, the battery cell marked on the left is the second battery cell 20, and the battery cell on the right is the first battery cell 10.

[0054] It can be understood that in the battery string 200, the battery string 200 may include two battery cells connected in series, three battery cells connected in series, or other more battery cells. Specifically, the number of battery cells to be connected in series may be determined according to actual usage. In addition, in the embodiments of the present application, the size and type of the battery cells are not limited either. The specifications and sizes of adjacent battery cells may be the same or different to meet different requirements.

[0055] In the embodiments of the present application, the doping types of the first doping layer and the second doping layer are not limited. For example, the first doping layer and the second doping layer may be a P-type doping layer and an N-type doping layer respectively; it may also be that the first doping layer is an N-type doping layer and the second doping layer may be a P-type doping layer, as long as the polarities of the two are opposite to meet different requirements. In some embodiments, the first doping layer may be a P-type polysilicon layer, a P-type amorphous silicon layer, or a P-type microcrystalline silicon layer, which is not specifically limited here. Similarly, the second doping layer may be an N-type polysilicon layer, an N-type amorphous silicon layer, or an N-type microcrystalline silicon layer, which is not specifically limited here. When the first doping layer is a P-type doping layer and the second doping layer is an N-type doping layer, a P-type grid line may be further provided corresponding to the first doping layer, and an N-type grid line may be further provided corresponding to the second doping layer, which is not specifically limited here.

[0056] In some embodiments, P-type doping refers to doping group III elements, including elements such as boron, aluminum, gallium, indium, and thallium; N-type doping refers to doping group V elements, including elements such as nitrogen, phosphorus, arsenic, antimony, and bismuth, which is not specifically limited here.

[0057] In addition, in some embodiments, the first doping layer and the second doping layer may also be of composite doping. For example, N-type doping also includes a small amount of P-type doping elements. Among them, the content of N-type doping elements in the second doping layer is higher than 20% of the content of P-type doping elements to ensure the opposite polarity to the first doping layer.

[0058] It can be understood that in such an embodiment, the back-contact battery assembly 100 may further include a frame, a backsheet, a photovoltaic glass, and an encapsulant film. The encapsulant film can be filled between the front side 11 and the back side 12 of the cell, between the photovoltaic glass, adjacent cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulant film can be an EVA encapsulant film or a POE encapsulant film, which can be specifically selected according to the actual situation and is not limited herein.

[0059] The photovoltaic glass can cover the encapsulant film on the front side 11 of the cell. The photovoltaic glass can be ultra-white glass, which has a high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, the light transmittance of the ultra-white glass can reach more than 92%, which can protect the cell without significantly affecting the efficiency of the cell as much as possible. At the same time, the encapsulant film can bond the photovoltaic glass and the cell together, and the presence of the encapsulant film can seal and insulate the cell as well as prevent water and moisture.

[0060] The backsheet can be attached to the encapsulant film on the back side 12 of the cell. The backsheet can protect and support the cell, and has reliable insulation, water resistance, and aging resistance. The backsheet can have multiple choices and is usually tempered glass, plexiglass, aluminum alloy TPT composite film, etc., which can be specifically set according to the specific situation and is not limited herein. The whole composed of the backsheet, the cell, the encapsulant film, and the photovoltaic glass can be set on the frame. The frame, as the main external support structure of the entire back-contact battery assembly 100, can stably support and install the back-contact battery assembly 100. For example, the back-contact battery assembly 100 can be installed at the required installation position through the frame.

[0061] Embodiment 2

[0062] Please refer to Figure 1 and Figure 2 In some alternative embodiments, at least some of the first grid lines 121 and the second grid lines 122 are disposed in the accommodation space 31, and all the first grid lines 121 disposed in the accommodation space 31 are connected to the solder strip 30 through the conductive connection structure 40.

[0063] In this way, the first grid lines 121 and the second grid lines 122 are alternately disposed along the first direction in the accommodation space 31, and the current of the first doping layer and the second doping layer in the accommodation space 31 can be conducted out, further improving the power generation efficiency of the cell.

[0064] Specifically, part of the first grid lines 121 and part of the second grid lines 122 are disposed within the accommodation space 31 and are connected to the welding tape 30 through the conductive connection structure 40. The first grid lines 121 and the second grid lines 122 are alternately arranged along the first direction within the accommodation space 31. At the same time, all the first grid lines 121 disposed within the accommodation space 31 are connected to the welding tape 30 through the conductive connection structure 40, which can effectively conduct the current of the first doping layer and the second doping layer within the accommodation space 31, further improving the power generation efficiency of the battery cell. In this way, by optimizing the connection design between the grid lines and the welding tape 30, the current of the doping layer can be more fully collected and conducted, improving the power generation efficiency of the battery cell. The conductive connection structure 40 within the accommodation space 31 reduces the impedance in the current conduction path, reduces the power loss, and improves the overall power generation performance. The existence of the conductive connection structure 40 not only ensures the efficient conduction of the current, but also improves the connection stability between the battery cell and the welding tape 30, preventing the problem of poor contact caused by mechanical stress or environmental changes.

[0065] Embodiment III

[0066] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the insulating structure 50 is prepared by laying or coating.

[0067] In this way, the insulating structure 50 can be prepared by laying or coating, so that the insulating structure 50 can be accurately disposed on the corresponding grid lines. In addition, the insulating structure 50 can be prepared on the battery cell by various preparation methods, and thus can meet the requirements of various scenarios.

[0068] It can be understood that the first grid lines 121 and the second grid lines 122 extend along the second direction and are alternately laid on the battery cell along the first direction. At both ends of the first grid lines 121 and the second grid lines 122 in the second direction, they can extend into positions close to the edge of the battery cell. At this time, a plurality of welding tapes 30 can be disposed on the battery cell to connect the grid lines of the same polarity on one battery cell together. Since the welding tape 30 extends along the first direction, it will continuously pass through a plurality of first grid lines 121 and second grid lines 122. At this time, the insulating structure 50 is disposed on the second grid lines 122 at the positions covered by the welding tape 30 to avoid connection with the second grid lines 122, thereby avoiding the problem of short circuit.

[0069] In the embodiments of the present application, the form and preparation method of the insulating structure 50 are not limited to meet different requirements. In one embodiment, the insulating structure 50 is an insulating glue layer provided on the corresponding gate line through a spraying process. In this way, the setting position of the insulating structure 50 is more accurate, the speed of setting the insulating structure 50 is faster, and the spraying equipment does not need to be in direct contact with the battery chip, which can reduce the pollution and damage to the battery chip. Further, the insulating glue layer can be subjected to at least one of photocuring and thermal curing, and the duration of photocuring is less than or equal to 2 s.

[0070] Embodiment 4

[0071] Please refer to Figure 1 and Figure 2 In some alternative embodiments, the conductive connection structure 40 is solder paste, conductive glue, or other metal conductive materials.

[0072] In this way, the conductive connection structure 40 uses materials such as solder paste or conductive glue that are easy to deform, which can cope with the irregular accommodation space 31 that appears during the process preparation to ensure that the conductive connection structure 40 can connect the first gate line 121 and the solder strip 30 together.

[0073] In the embodiments of the present application, the type of the conductive connection structure 40 is not limited to meet different requirements. In one example, when the conductive connection structure 40 is solder paste, the solder paste has good wettability and fluidity, which is suitable for filling irregular spaces to ensure the stability of electrical connection. In another example, when the conductive connection structure 40 is conductive glue, the conductive glue has softness and good adhesiveness, and can closely adhere between the gate line and the solder strip 30 to adapt to accommodation spaces 31 of different shapes and sizes. In yet another example, when the conductive connection structure 40 is other metal conductive materials, the metal materials have excellent electrical conductivity, which can ensure the efficient conduction of current. Using the flexibility and conductivity of these materials can ensure the smooth conduction of current and further improve the power generation efficiency of the back-contact battery module 100.

[0074] Further, since the solder strip 30 is stretched and arranged on the first battery chip 10 and the second battery chip 20 during the process preparation, irregular accommodation spaces 31 are likely to appear. When the conductive connection structure 40 adopts solder paste, conductive glue, or other metal conductive materials, the flexibility of the process preparation can be improved. The solder paste and conductive glue can be completed through simple coating or dispensing processes during use, with simple operation and low cost. At the same time, due to the fluidity and plasticity of the materials themselves, they can adapt to the irregular accommodation spaces 31 that appear during the preparation process to ensure the integrity and reliability of the conductive connection structure 40.

[0075] Embodiment 5

[0076] Please refer to Figure 1 andFigure 2 In some alternative embodiments, the length of the conductive connection structure 40 in the first direction is greater than 6 mm. For example, the length of the conductive connection structure 40 in the first direction may be 6.1 mm, 6.2 mm, 6.3 mm, 6.4 mm, 6.5 mm, 6.6 mm, 6.7 mm, 6.8 mm, 6.9 mm, 7 mm, 7.5 mm, 8 mm.

[0077] In this way, during the process of process preparation, the solder strip 30 can be connected to the first solar cell 10 and the second solar cell 20, and the sizes of the accommodating spaces 31 are often different. Therefore, the conductive connection structure 40 is set to have a length greater than 6 mm in the first direction, so that under different process errors, the conductive connection structure 40 can connect all the first grid lines 121 in the accommodating structure.

[0078] Specifically, in the embodiment of the present application, the type of the solder strip 30 is not limited to meet different requirements. For example, the solder strip 30 can be a round solder strip 30 or a flat wide solder strip 30. It should be noted that when the solder strip 30 is disposed on the first solar cell 10 and the second solar cell 20, due to process errors, the length of the accommodating space 31 in the first direction is not uniform. The length of the accommodating space 31 in the first direction is 0.5 mm - 6 mm. Therefore, it is only necessary that the length of the conductive connection structure 40 in the first direction is greater than 6 mm. Exemplarily, the length of the conductive connection structure 40 in the first direction is 7 mm, which can effectively connect the first grid line 121 and the solder strip 30 in the accommodating space 31 and ensure stable connection.

[0079] Embodiment Six

[0080] Please refer to Figure 2 and Figure 3 In some alternative embodiments, the thickness of the conductive connection structure 40 in the third direction is 30 μm - 300 μm, where the third direction is perpendicular to the first direction and the second direction. For example, the thickness of the conductive connection structure 40 in the third direction may be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 260 μm, 280 μm, 300 μm.

[0081] In this way, by setting the thickness of the conductive connection structure 40 within this range, on the one hand, the problem of virtual soldering and missed soldering due to the too thin conductive connection structure 40 can be avoided, and on the other hand, the problem that the too thick conductive connection structure 40 affects the overall thickness of the back-contact battery module 100 can be avoided.

[0082] Embodiment Seven

[0083] Please refer toFigure 1 and Figure 2 , in some alternative embodiments, in the second direction, the width of the welding strip 30 is greater than the width of the conductive connection structure 40.

[0084] In this way, the welding strip 30 can shield the conductive connection structure 40, preventing the conductive connection structure 40 from being exposed and affecting the normal operation of the back-contact battery module 100. The exposed conductive connection structure 40 is likely to come into contact with other conductive components or circuits, resulting in a short circuit. At the same time, since the material used for the conductive connection structure 40 has a certain degree of softness and elasticity, by shielding the conductive connection structure 40 with the welding strip 30, it is possible to prevent the conductive connection structure 40 from being pressed out and exposed when the welding strip 30 is pressed on it. In this way, not only the durability and reliability of the module are improved, but also problems such as mechanical damage or oxidation of the conductive connection structure 40 can be prevented, further enhancing the service life and performance stability of the back-contact battery module 100.

[0085] Embodiment Eight

[0086] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, in the second direction, the width of the insulating structure 50 is greater than the width of the conductive connection structure 40.

[0087] In this way, in the second direction, the width of the insulating structure 50 is greater than the width of the conductive connection structure 40 to prevent the conductive connection structure 40 from being short-circuited with the second grid line 122.

[0088] Specifically, the wider insulating structure 50 provides a larger physical isolation area, enhancing the electrical insulation effect and avoiding possible electrical interference and current leakage. During the actual production process, process errors may cause slight deviations in the position of the conductive connection structure 40. The insulating structure 50 with a larger width can compensate for these deviations, ensuring that the insulation effect is not affected. At the same time, the wider insulating structure 50 can avoid insulation failure caused by process variations, aging, etc., enhancing the stability and reliability of the back-contact battery module 100 during long-term use.

[0089] Embodiment Nine

[0090] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the thickness of the insulating structure 50 is 25 μm - 40 μm. For example, the thickness of the insulating structure 50 can be 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm.

[0091] Thus, the thickness of the insulating structure 50 is set within this range. On the one hand, it can physically isolate the second gate line 122 and ensure insulation between the second gate line 122 and the conductive connection structure 40.

[0092] Exemplarily, the thickness of the insulating structure 50 can be set to 30 μm, which can ensure effective physical isolation, guarantee good insulation between the second gate line 122 and the conductive connection structure 40, and improve the overall electrical performance and reliability of the back-contact battery assembly 100.

[0093] Embodiment Ten

[0094] Please refer to Figure 5 and Figure 6 , in some alternative embodiments, when at least a part of the back surface 12 of the first cell 10 and the front surface 11 of the second cell 20 are stacked together, a receiving space 31 is formed on the side of the back surface 12 of the first cell 10 close to the second cell 20. The solder strip 30 further includes a second solder strip 33 and a third solder strip 34. The second solder strip 33 is disposed on the back surface 12 of the first cell 10 and at least partially extends into the back surface 12 of the second cell 20, and the third solder strip 34 is located on the back surface 12 of the second cell 20.

[0095] Thus, the edge portions of the back surface 12 of the first cell 10 and the front surface 11 of the second cell 20 are stacked together, which can effectively increase the light-receiving area of the back-contact battery assembly 100.

[0096] Embodiment Eleven

[0097] Please refer to Figure 1 and Figure 3 , in some alternative embodiments, the conductive connection structure 40 is formed with an inclined surface 41 on the side away from the first cell 10, and the inclined surface 41 is connected to the solder strip 30.

[0098] Thus, the inclined surface 41 has the same inclined direction as the solder strip 30, so that the conductive connection structure 40 can better fit and connect with the solder strip 30, ensuring stable connection between the conductive connection structure 40 and the solder strip 30.

[0099] Embodiment Twelve

[0100] Please refer to Figure 5 and Figure 6 , in some alternative embodiments, the back-contact battery assembly 100 further includes a bus bar 60, and the bus bar 60 is disposed on the back surface 12 of the second cell 20;

[0101] The bus bar 60 is connected to the second solder strip 33 and is located on the side of the second solder strip 33 away from the second cell 20;

[0102] The bus bar 60 is connected to the second solder tape 33 and is located on the side of the second solder tape 33 close to the second solar cell 20.

[0103] Specifically, the bus bar 60 is arranged on the side of the second solder tape 33 facing away from the second solar cell 20, which can avoid affecting the accommodation space 31 and the components inside the accommodation space 31. The bus bar 60 is arranged on the side of the second solder tape 33 close to the second solar cell 20, which can increase the volume of the accommodation space 31, and then can reasonably adjust the size of the conductive connection structure 40 to ensure stable connection.

[0104] Embodiment Thirteen

[0105] Please refer to Figure 7 and Figure 8 , in some alternative embodiments, when the front surface 11 of the first solar cell 10 and the back surface 12 of the second solar cell 20 are at least partially stacked together, the accommodation space 31 is formed on the side of the back surface 12 of the first solar cell 10 close to the second solar cell 20. The solder tape 30 further includes a second solder tape 33 and a third solder tape 34. The second solder tape 33 is arranged on the back surface 12 of the first solar cell 10 and at least partially extends into the back surface 12 of the second solar cell 20. The third solder tape 34 is located on the back surface 12 of the second solar cell 20.

[0106] Please refer to Figure 7 and Figure 8 , in some alternative embodiments, the back-contact solar cell module 100 further includes a bus bar 60, and the bus bar 60 is arranged on the back surface 12 of the first solar cell 10;

[0107] The bus bar 60 is connected to the second solder tape 33 and is located on the side of the second solder tape 33 facing away from the second solar cell 20;

[0108] The bus bar 60 is connected to the second solder tape 33 and is located on the side of the second solder tape 33 close to the second solar cell 20.

[0109] Specifically, the bus bar 60 is arranged on the side of the second solder tape 33 facing away from the second solar cell 20, which can avoid affecting the accommodation space 31 and the components inside the accommodation space 31. The bus bar 60 is arranged on the side of the second solder tape 33 close to the second solar cell 20, which can, to a certain extent, eliminate the volume of the accommodation space 31, and at the same time, can make the lifting arc of the second solder tape 33 smaller to ensure stable connection.

[0110] It should be noted that when the bus bar 60 is arranged between the solar cell and the second solder tape 33, the bus bar 60 and part of the grid lines need to be insulated to avoid short circuit problems at the position of the bus bar 60.

[0111] In addition, in the embodiments of the present application, the specific position of the bus bar 60 is not limited to meet different requirements.

[0112] Further, the back contact battery assembly 100 further includes an insulating layer 70 disposed between the bus bar 60 and the third solder tape 34.

[0113] Embodiment Fourteen

[0114] Please refer to Figure 9 and Figure 10 The photovoltaic system 300 provided by the embodiment of the present application includes the back contact battery assembly 100 of any one of the above embodiments.

[0115] In the back contact battery assembly 100 and the photovoltaic system 300 of the embodiment of the present application, the back contact battery assembly 100 includes a battery string 200, a solder tape 30, a conductive connection structure 40, and an insulating structure 50. The battery string 200 includes adjacent first battery cells 10 and second battery cells 20. The first battery cells 10 and the second battery cells 20 are arranged along a first direction. The first battery cells 10 and the second battery cells 20 are at least partially stacked together. First grid lines 121 and second grid lines 122 are formed on the back surfaces 12 of the first battery cells 10 and the second battery cells 20. The first grid lines 121 and the second grid lines 122 extend along a second direction and are alternately arranged along the first direction. The first grid lines 121 and the second grid lines 122 have opposite polarities. The solder tape 30 is disposed on the back surface 12 of the first battery cell 10 and extends along the first direction. A receiving space 31 is formed between one side of the first battery cell 10 close to the second battery cell 20 and the solder tape 30. The conductive connection structure 40 is at least partially laid in the receiving space 31 and connects the first grid line 121 and the solder tape 30 in the receiving space 31. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is disposed in the receiving space 31 and between the second grid line 122 and the solder tape 30. In this way, the solder tape 30 can be connected to the first grid line 121 in the receiving space 31 through the conductive connection structure 40, so that the current in the receiving space 31 can be collected, thereby improving the power generation efficiency of the back contact battery assembly 100. At the same time, the insulating structure 50 can be disposed between the second grid line 122 and the conductive connection structure 40 to avoid a short - circuit problem.

[0116] In this embodiment, the photovoltaic system 300 can be applied in a photovoltaic power station, such as a ground power station, a rooftop power station, a water surface power station, etc., or can also be applied to devices or apparatuses that use solar energy for power generation, such as a user solar power supply, a solar street lamp, a solar vehicle, a solar building, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system 300 are not limited thereto, that is to say, the photovoltaic system 300 can be applied in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system 300 can include a photovoltaic array, a busbar box, and an inverter. The photovoltaic array can be an array combination of multiple back-contact battery components 100. For example, multiple back-contact battery components 100 can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the busbar box, and the busbar box can collect the current generated by the photovoltaic arrays. The collected current flows through the inverter and is converted into alternating current required by the mains power grid and then connected to the mains network to achieve solar power supply.

[0117] In the description of this specification, the description with reference to terms such as "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means 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 can be combined in a suitable manner in any one or more embodiments or examples.

[0118] 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 back contact battery assembly, characterized in that: include: A battery string, comprising adjacent first battery sheets and second battery sheets, wherein the first battery sheets and the second battery sheets are distributed and arranged along a first direction, the first battery sheets and the second battery sheets are at least partially stacked together, a first grid line and a second grid line are formed on the back of the first battery sheets and the second battery sheets, the first grid line and the second grid line extend along a second direction and are alternately arranged along the first direction, and the first grid line and the second grid line have opposite polarities; A solder strip, the solder strip being arranged on the back side of the first battery cell and extending along the first direction, an accommodating space being formed between a side of the first battery cell close to the second battery cell and the solder strip; A conductive connection structure, which is at least partially laid in the accommodating space and connects the first gate line and the welding strip in the accommodating space; An insulating structure covers the second gate line, and the insulating structure is arranged in the accommodating space and between the second gate line and the welding strip.

2. The back contact battery assembly according to claim 1, characterized in that: The welding strip includes a first welding strip extending along the first direction and connecting the back side of the first battery cell and the back side of the second battery cell, and an accommodating space is formed between a side of the first battery cell close to the second battery cell and the first welding strip.

3. The back contact battery assembly according to claim 1, characterized in that: When the back side of the first battery cell and the front side of the second battery cell are at least partially stacked together, the accommodating space is formed on the side of the back side of the first battery cell close to the second battery cell, and the welding strip also includes a second welding strip and a third welding strip, the second welding strip is arranged on the back side of the first battery cell and at least partially extends into the back side of the second battery cell, and the third welding strip is located on the back side of the second battery cell.

4. The back contact battery assembly according to claim 3, characterized in that: The back contact battery assembly further includes a bus bar, and the bus bar is arranged on the back side of the second battery sheet; The bus bar is connected to the second welding strip and is located on a side of the second welding strip away from the second battery cell; The bus bar is connected to the second welding ribbon and is located on a side of the second welding ribbon close to the second battery cell.

5. The back contact battery assembly according to claim 1, characterized in that: When the front side of the first battery cell and the back side of the second battery cell are at least partially stacked together, the accommodating space is formed on the back side of the first battery cell close to the second battery cell, and the welding strip also includes a second welding strip and a third welding strip, the second welding strip is arranged on the back side of the first battery cell and at least partially extends into the back side of the second battery cell, and the third welding strip is located on the back side of the second battery cell.

6. The back contact battery assembly according to claim 5, characterized in that: The back contact battery assembly further includes a bus bar, and the bus bar is arranged on the back side of the first battery sheet; The bus bar is connected to the second welding strip and is located on a side of the second welding strip facing away from the first battery cell; The bus bar is connected to the second welding ribbon and is located on a side of the second welding ribbon close to the first battery cell.

7. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: The insulating structure is prepared by laying or coating.

8. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: The conductive connection structure is solder paste or conductive glue or other metallic conductive materials.

9. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: The length of the conductive connection structure along the first direction is greater than 6 mm.

10. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: The thickness of the conductive connection structure along the third direction is 30 μm-300 μm, wherein the third direction is perpendicular to the first direction and the second direction.

11. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: In the second direction, the width of the soldering strip is greater than the width of the conductive connection structure.

12. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: In the second direction, the width of the insulating structure is greater than the width of the conductive connection structure.

13. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: The thickness of the insulating structure is 25 μm-40 μm.

14. The back contact battery assembly according to any one of claims 1 to 6, characterized in that: The conductive connection structure is formed with an inclined surface on a side away from the first battery cell, and the inclined surface is connected to the welding strip.

15. The back contact battery assembly according to claim 4 or 6, characterized in that: The back-contact battery assembly further includes an insulating layer disposed between the bus bar and the third welding ribbon.

16. A photovoltaic system, characterized in that: Comprising a back contact battery assembly as described in any one of claims 1-15.

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