Back contact battery module and photovoltaic system

Abstract

The present application is applicable to the field of solar cell technology, and provides a back-contact cell assembly and a photovoltaic system. The back-contact cell assembly includes a cell string, a welding strip, a conductive connection structure and an insulating structure. The first cell sheet and the second cell sheet are distributed and arranged along the first direction. The first cell sheet and the second cell sheet are at least partially stacked together. An accommodation space is formed between the side of the first cell sheet close to the second cell sheet and the welding strip. The conductive connection structure is at least partially laid in the accommodation space. The length L of the conductive connection structure along the first direction satisfies the following relationship: 0<L≤D / tanα, α is the angle between the direction in which the welding strip is lifted and the first direction, and D is the thickness of the second cell sheet along the third direction. In this way, the welding strip can be connected to the first grid line in the accommodation space through the conductive connection structure, so that the current in the accommodation space can be collected, thereby improving the power generation efficiency of the back-contact cell assembly.

Description

Technical Field

[0001] The present application belongs to the technical field of solar cells, and in particular to a back-contact cell assembly and a photovoltaic system. Background Art

[0002] At present, a back-contact cell refers to a solar cell with no electrode on the light-facing side of the cell, and both the positive and negative electrodes are arranged on the back-light side of the cell, thereby reducing the shading of the electrode to the cell, increasing the short-circuit current of the cell, and improving the energy conversion efficiency of the cell. In the related art, the edges of multiple back-contact cells are stacked together to increase the light-receiving area of ​​the cell. However, stacked back-contact cells will prevent the current at the edge of one of the back-contact cells from being collected, resulting in a decrease in the power generation efficiency of the cell. Summary of the invention

[0003] The embodiments of the present application provide a back-contact cell assembly and a photovoltaic system, which are intended to solve the problem that the current at the edge of the photovoltaic cell cannot be collected when the photovoltaic cell uses a stacked structure.

[0004] A back-contact battery assembly provided in an embodiment of the present application includes a battery string, a welding strip, a conductive connection structure and an insulating structure, the battery string includes a first battery sheet and a second battery sheet adjacent to each other, the first battery sheet and the second battery sheet are distributed and arranged along a first direction, the first battery sheet and the second battery sheet are at least partially stacked together, a first grid line and a second grid line are formed on the back of the first battery sheet and the second battery sheet, the first grid line and the second grid line extend along a second direction and are alternately arranged along the first direction, the first grid line and the second grid line have opposite polarities, the welding strip is arranged on the back of the first battery sheet and extends along the first direction, An accommodating space is formed between a side of the first battery cell close to the second battery cell and the welding strip, the conductive connection structure is at least partially laid in the accommodating space, and connects the first gate line and the welding strip in the accommodating space, the insulating structure covers the second gate line, and the insulating structure is arranged in the accommodating space and is located between the second gate line and the welding strip; the length L of the conductive connection structure along the first direction satisfies the following relationship: 0<L≤D / tanα; wherein α is the angle between the direction in which the welding strip is lifted and the first direction, and D is the thickness of the second battery cell along a third direction, and the third direction is perpendicular to the second direction and the first direction.

[0005] In the back-contact battery assembly of the embodiment of the present application, the back-contact battery assembly includes a battery string, a welding strip, 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 distributed and arranged along a first direction, the first battery cells and the second battery cells are at least partially stacked together, the backs of the first battery cells and the second battery cells are formed with first grid lines and second grid lines, the first grid lines and the second grid lines extend along the second direction and are alternately arranged along the first direction, the first grid lines and the second grid lines have opposite polarities, the welding strip is arranged on the back of the first battery cell and along the first The first battery cell is extended in a direction, and a receiving space is formed between the side of the first battery cell close to the second battery cell and the welding strip. The conductive connection structure is at least partially laid in the receiving space and connects the first grid line and the welding strip in the receiving space. The insulating structure covers the second grid line. The insulating structure is arranged in the receiving space and is located between the second grid line and the welding strip. The length L of the conductive connection structure along the first direction satisfies the following relationship: 0<L≤D / tanα; wherein α is the angle between the direction in which the welding strip is lifted and the first direction, and D is the thickness of the second battery cell along the third direction, and the third direction is perpendicular to the second direction and the first direction. In this way, the welding strip 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 battery assembly. At the same time, the insulating structure can be arranged between the second grid line and the conductive connection structure to avoid the problem of short circuit.

[0006] Furthermore, the welding strip includes a first welding strip, which extends along the first direction and connects the back side of the first battery cell and the back side of the second battery cell, and an accommodating space is formed between the side of the first battery cell close to the second battery cell and the first welding strip.

[0007] Furthermore, 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.

[0008] Furthermore, the back contact battery assembly further comprises a bus bar, and the bus bar is arranged on the back side of the second battery sheet;

[0009] 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;

[0010] 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.

[0011] Furthermore, 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 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.

[0012] Furthermore, the back contact battery assembly further comprises a bus bar, and the bus bar is arranged on the back side of the first battery sheet;

[0013] 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;

[0014] 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.

[0015] Furthermore, the insulating structure is prepared by laying or coating.

[0016] Furthermore, the conductive connection structure is solder paste or conductive glue or other metallic conductive materials.

[0017] Furthermore, the length of the conductive connection structure along the first direction is greater than 6 mm.

[0018] Furthermore, 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.

[0019] Furthermore, in the second direction, the width of the soldering strip is greater than the width of the conductive connection structure.

[0020] Furthermore, in the second direction, the width of the insulating structure is greater than the width of the conductive connection structure.

[0021] Furthermore, the thickness of the insulating structure is 25 μm-40 μm.

[0022] Furthermore, 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.

[0023] Furthermore, the back contact battery assembly further includes an insulating layer, and the insulating layer is arranged between the bus bar and the third welding ribbon.

[0024] Furthermore, the angle α between the lifting direction of the welding strip and the first direction is adjusted according to the yield degree of the welding strip.

[0025] Furthermore, the yield strength of the welding strip is adjusted to be less than or equal to 75Mpa.

[0026] Furthermore, a thickness D of the second battery cell along the third direction is 90 μm-200 μm.

[0027] The photovoltaic system provided in the embodiments of the present application includes the back-contact cell assembly described in any one of the embodiments above.

[0028] In the back-contact battery assembly and photovoltaic system of the embodiment of the present application, the back-contact battery assembly includes a battery string, a welding strip, 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 distributed and arranged along a first direction, the first battery cells and the second battery cells are at least partially stacked together, the backs of the first battery cells and the second battery cells are formed with first grid lines and second grid lines, 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 welding strip is arranged on the back of the first battery cell and Extending along the first direction, a accommodating space is formed between the side of the first battery cell close to the second battery cell and the welding strip, the conductive connection structure is at least partially laid in the accommodating space, and connects the first grid line and the welding strip in the accommodating space, the insulating structure covers the second grid line, and the insulating structure is arranged in the accommodating space and is located between the second grid line and the welding strip; the length L of the conductive connection structure along the first direction satisfies the following relationship: 0<L≤D / tanα; wherein α is the angle between the direction in which the welding strip is lifted and the first direction, and D is the thickness of the second battery cell along the third direction, and the third direction is perpendicular to the second direction and the first direction. In this way, the welding strip can be connected to the first grid line in the accommodating space through the conductive connection structure, so that the current in the accommodating space can be collected, thereby improving the power generation efficiency of the back contact battery assembly, and at the same time, the insulating structure can be arranged between the second grid line and the conductive connection structure to avoid the problem of short circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a partial planar structural schematic diagram of a back contact battery according to an embodiment of the present application;

[0030] Figure 2 is a schematic diagram of a partial cross-sectional structure of a back contact battery according to an embodiment of the present application;

[0031] Figure 3 is another partial cross-sectional schematic diagram of a back contact battery according to an embodiment of the present application;

[0032] Figure 4 This is an embodiment of the present application Figure 3 A is an enlarged schematic diagram;

[0033] Figure 5is another partial cross-sectional schematic diagram of a back contact battery according to an embodiment of the present application;

[0034] Figure 6 is another partial cross-sectional schematic diagram of a back contact battery according to an embodiment of the present application;

[0035] Figure 7 is another partial cross-sectional schematic diagram of a back contact battery according to an embodiment of the present application;

[0036] Figure 8 is another partial cross-sectional schematic diagram of a back contact battery according to an embodiment of the present application;

[0037] Fig. 9 is a schematic diagram of the module structure of a back contact battery according to an embodiment of the present application;

[0038] Fig.10 It is a schematic diagram of the module structure of a photovoltaic system according to an embodiment of the present application.

[0039] Description of main component symbols:

[0040] Back contact battery assembly 100, first battery cell 10, front side 11, back side 12, first grid line 121, second grid line 122, second battery cell 20, welding strip 30, accommodating space 31, first welding strip 32, second welding strip 33, third welding strip 34, conductive connection structure 40, inclined surface 41, insulating structure 50, bus bar 60, insulating layer 70, battery string 200, photovoltaic system 300. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below 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 throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limiting 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 intended to limit the present application.

[0042] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are 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, and therefore should not be understood as a limitation on the present application.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0044] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0045] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0046] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, 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.

[0047] In the related art, a solar cell is a semiconductor device that directly converts the energy of sunlight into electrical energy. Solar cells use the photovoltaic effect to excite electrons by absorbing photons, and conduct these electrons to generate current through a built-in electric field. A back-contact cell refers to a solar cell in which the light-facing side of the cell has no electrode, and the positive and negative electrodes are both arranged on the back-light side of the cell, thereby reducing the blocking of the cell by the electrode, increasing the short-circuit current of the cell, and improving the energy conversion efficiency of the cell. In the prior art, in order to obtain a larger light-receiving area and eliminate the gaps between different cells, the edge portions of two adjacent cells are superimposed together in the back-contact cell. However, this will cause the fine grid located at the edge portion to be unable to be connected by the welding strip, and the current at the edge position cannot be collected, resulting in a decrease in the power generation efficiency of the battery. In an embodiment of the present application, a conductive connection structure is provided at the edge portion to connect the welding strip and the corresponding fine grid, so that all the current of the cell is collected to improve the power generation efficiency.

[0048] Embodiment 1

[0049] See also Figures 1 to 4 The embodiment of the present application provides a back-contact battery assembly 100, the back-contact battery assembly 100 includes a battery string 200, a welding 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 distributed and arranged along a first direction, the first battery cells 10 and the second battery cells 20 are at least partially stacked together, the back sides 12 of the first battery cells 10 and the second battery cells 20 are both formed with first grid lines 121 and second grid lines 122, 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, and the welding strip 30 is arranged on the first battery cells. The back side 12 of the cell 10 extends along the first direction, and an accommodating space 31 is formed between the side of the first cell 10 close to the second cell 20 and the welding strip 30. The conductive connection structure 40 is at least partially laid in the accommodating space 31, and connects the first grid line 121 and the welding strip 30 in the accommodating space 31. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is arranged in the accommodating space 31 and is located between the second grid line 122 and the welding strip 30. The length L of the conductive connection structure 40 along the first direction satisfies the following relationship: 0<L≤D / tanα, wherein α is the angle between the direction in which the welding strip 30 is lifted and the first direction, and D is the thickness of the second cell 20 along the third direction, and the third direction is perpendicular to the second direction and the first direction.

[0050] Furthermore, the welding strip 30 includes a first welding strip 32, which extends along a first direction and connects the back side 12 of the first battery cell 10 and the back side 12 of the second battery cell 20, and an accommodating space 31 is formed between the side of the first battery cell 10 close to the second battery cell 20 and the first welding strip 32.

[0051] In the back contact battery assembly 100 of the embodiment of the present application, the back contact battery assembly 100 includes a battery string 200, a welding 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 distributed and arranged along a first direction, the first battery cells 10 and the second battery cells 20 are at least partially stacked together, the back sides 12 of the first battery cells 10 and the second battery cells 20 are both formed with first grid lines 121 and second grid lines 122, the first grid lines 121 and the second grid lines 122 extend along the second direction and are alternately arranged along the first direction, the first grid lines 121 and the second grid lines 122 have opposite polarities, and the welding strip 30 is arranged on the first battery cells. The back side 12 of 10 extends along the first direction, and an accommodating space 31 is formed between the side of the first battery cell 10 close to the second battery cell 20 and the welding strip 30. The conductive connection structure 40 is at least partially laid in the accommodating space 31, and connects the first grid line 121 and the welding strip 30 in the accommodating space 31. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is arranged in the accommodating space 31 and is located between the second grid line 122 and the welding strip 30. The length L of the conductive connection structure 40 along the first direction satisfies the following relationship: 0<L≤D / tanα, wherein α is the angle between the direction in which the welding strip 30 is lifted and the first direction, and D is the thickness of the second battery cell 20 along the third direction, and the third direction is perpendicular to the second direction and the first direction. In this way, the welding strip 30 can be connected to the first grid line 121 in the accommodating space 31 through the conductive connecting structure 40, so that the current in the accommodating 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 connecting structure 40 to avoid the problem of short circuit.

[0052] In this embodiment, the front side 11 of the cell is used to receive light, and the back side 12 of the cell includes a plurality of first doping layers and second doping layers (not shown in the figure) that are alternately arranged, and the first doping layers are provided with first gate lines 121, and the second doping layers are provided with second gate lines 122. The first gate lines 121 and the second gate lines 122 extend along the second direction and are alternately arranged along the first direction, and 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.

[0053] In the embodiment of the present application, the back side 12 of the battery cell has no main grid, and the first grid line 121 and the second grid line 122 can directly realize the convergence of current through the welding strip 30. The welding strip 30 includes a first welding strip 32 and a second welding strip 33, which 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, and the first welding strip 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 strip 33 to connect 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 strip 33 is not limited to meet various needs. At this time, an insulating structure 50 is provided between the first welding ribbon 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 ribbon 32 and the first grid line 121 of the second battery cell 20 to achieve insulation.

[0054] 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 assembly space and increasing costs due to excessive spacing. An accommodating space 31 is formed between the side of the first battery cell 10 close to the second battery cell 20 and the welding strip 30, and the conductive connection structure 40 is at least partially laid in the accommodating space 31, and connects the first grid line 121 and the welding strip 30 in the accommodating space 31. The insulating structure 50 covers the second grid line 122, and the insulating structure 50 is arranged in the accommodating space 31 and is located between the second grid line 122 and the welding strip 30. In this way, the current generated by the first doping layer corresponding to the first grid line 121 inside the accommodating space 31 can also be guided out by the welding strip 30, so as to realize that all the doping layers of the battery cell generate electrical energy, thereby improving the power generation efficiency of the back contact battery assembly 100. Of course, in some embodiments, the conductive connection structure 40 is filled in the entire accommodating space 31, and then all the first grid lines 121 inside the accommodating space 31 can be connected and conducted out through the welding strip 30.

[0055] 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 strip 32 can span the first battery cell 10 and the second battery cell 20, and the first welding strip 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, the first welding strip 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 arranged 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.

[0056] 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.

[0057] Furthermore, the included angle α between the lifting direction of the solder tape 30 and the first direction is adjusted according to the yield strength of the solder tape 30. In this way, solder tapes 30 with different yield strengths can be selected to adjust the size of the included angle α, and then the specific dimension of the length L of the conductive connection structure 40 in the first direction can be calculated according to the thickness of the battery cell. In this way, the length of the conductive connection structure 40 in the accommodating space 31 in the first direction can be adjusted, and then the amount of the conductive connection structure 40 can be adjusted, which not only ensures that the conductive connection structure 40 can connect the solder tape 30 to the first grid line 121 in the accommodating space 31, but also avoids waste of the material of the conductive connection structure 40.

[0058] Furthermore, the yield strength adjustment of the solder tape 30 is less than or equal to 75 Mpa. In this way, the yield strength of the solder tape 30 is less than or equal to 75 Mpa, ensuring that the solder tape 30 can be bent and formed under a pressure of 75 Mpa and avoiding affecting other components.

[0059] Furthermore, the thickness D of the second battery cell 20 in the third direction is 90 μm - 200 μm. For example, the thickness D of the second battery cell 20 in the third direction may be 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm.

[0060] In this way, by setting the thickness D of the second battery cell 20 in the third direction within this range, it can ensure that various specifications of battery cells are covered and different requirements are met.

[0061] Specifically, the thickness D of the second battery cell 20 in the third direction is preferably 90 μm - 150 μm. In this way, the structure and operation of the battery cell can be ensured to be stable without increasing the thickness of the back-contact battery module 100.

[0062] Exemplarily, the thickness D of the second battery cell 20 along the third direction can be 120μm, and the yield strength of the welding strip 30 can be 70Mpa. This not only ensures the manufacturing stability in the process and will not affect other components, but also can compress the size of the accommodating space 31 and ensure the reasonable amount of material of the conductive connection structure 40, so that the conductive connection structure 40 can stably connect the welding strip 30 with the first gate line 121 in the accommodating space 31.

[0063] It should be noted that the yield strength of the soldering ribbon 30 refers to the magnitude of the pressure required to bend the soldering ribbon 30 into a desired shape.

[0064] It is understood that the "first" and "second" in the first battery cell 10 and the second battery cell 20 are relative concepts, referring to the two different back contact batteries. Figure 1 In the example, the battery cell on the left is marked as the second battery cell 20 , and the battery cell on the right is marked as the first battery cell 10 .

[0065] It is understandable 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 larger numbers of battery cells, and the number of battery cells to be connected in series may be determined based on actual usage. In addition, in the embodiment of the present application, the size and type of the battery cells are not limited, and the specifications and sizes of adjacent battery cells may be the same or different to meet different needs.

[0066] In the implementation manner 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 can be a P-type doping layer and an N-type doping layer, respectively; or the first doping layer can be an N-type doping layer, and the second doping layer can be a P-type doping layer, as long as the polarities of the two are opposite, so as to meet different needs. In some embodiments, the first doping layer can 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 can 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 gate line can also be provided on the corresponding first doping layer, and an N-type gate line can also be provided on the corresponding second doping layer, which is not specifically limited here.

[0067] In some embodiments, P-type doping refers to doping with Group III elements, including boron, aluminum, gallium, indium, thallium and other elements; N-type doping refers to doping with Group V elements, including nitrogen, phosphorus, arsenic, antimony, bismuth and other elements, which are not specifically limited here.

[0068] In addition, in some embodiments, the first doping layer and the second doping layer may also be composite doping, for example, N-type doping also includes a small amount of P-type doping elements. The content of the N-type doping element in the second doping layer is higher than 20% of the content of the P-type doping element to ensure that the polarity is opposite to that of the first doping layer.

[0069] It is understandable that in such an embodiment, the back contact battery assembly 100 may also include a frame, a back plate, a photovoltaic glass and an adhesive film. The adhesive film may be filled between the front 11 and the back 12 of the battery cell and the photovoltaic glass, adjacent battery cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film, which may be selected according to actual conditions and is not limited here.

[0070] Photovoltaic glass can cover the adhesive film on the front side 11 of the cell. The photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the cell without affecting the efficiency of the cell as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the cell together, and the presence of the adhesive film can seal and insulate the cell and make it waterproof and moisture-proof.

[0071] The backplane can be attached to the adhesive film on the back side 12 of the cell. The backplane can protect and support the cell and has reliable insulation, water resistance and aging resistance. There are multiple options for the backplane, which can usually be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. It can be set according to the specific situation and is not limited here. The whole composed of the backplane, cell, adhesive film and photovoltaic glass can be set on the frame. The frame serves as the main external support structure of the entire back contact battery assembly 100 and can provide stable support and installation for 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.

[0072] Embodiment 2

[0073] See also Figure 1 and Figure 2 In some optional embodiments, at least some of the first gate lines 121 and the second gate lines 122 are arranged in the accommodating space 31 , and all the first gate lines 121 arranged in the accommodating space 31 are connected to the welding strip 30 through the conductive connection structure 40 .

[0074] Thus, the first gate lines 121 and the second gate lines 122 are alternately arranged along the first direction in the accommodating space 31 , so that the current of the first doping layer and the second doping layer in the accommodating space 31 can be conducted out, further improving the power generation efficiency of the cell.

[0075] Specifically, part of the first gate line 121 and part of the second gate line 122 are arranged in the accommodating space 31, and are connected to the welding strip 30 through the conductive connection structure 40. The first gate line 121 and the second gate line 122 are alternately arranged along the first direction in the accommodating space 31, and all the first gate lines 121 arranged in the accommodating space 31 are connected to the welding strip 30 through the conductive connection structure 40, which can effectively conduct the current of the first doped layer and the second doped layer in the accommodating space 31, and further improve the power generation efficiency of the battery cell. In this way, by optimizing the connection design of the gate line and the welding strip 30, the current of the doped layer can be more fully collected and conducted, and the power generation efficiency of the battery cell is improved. The conductive connection structure 40 in the accommodating space 31 reduces the impedance in the current conduction path, reduces the power loss, and improves the overall power generation performance. The presence 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 strip 30, and prevents the poor contact problem caused by mechanical stress or environmental changes.

[0076] Embodiment 3

[0077] See also Figure 1 and Figure 2 In some optional embodiments, the insulating structure 50 is prepared by laying or coating.

[0078] In this way, the insulating structure 50 can be prepared by laying or coating, so that the insulating structure 50 can be accurately arranged on the corresponding grid line. In addition, the insulating structure 50 can be prepared on the battery cell in a variety of preparation methods, thereby meeting the needs of various scenarios.

[0079] 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, and the two ends of the first grid lines 121 and the second grid lines 122 in the second direction can extend to a position close to the edge of the battery cell. At this time, a plurality of welding strips 30 can be provided on the battery cell to connect the grid lines of the same polarity on a battery cell together, and since the welding strips 30 extend along the first direction, they will continuously pass through a plurality of first grid lines 121 and second grid lines 122. At this time, the insulating structure 50 is provided at a position between the second grid line 122 and the welding strips 30 to prevent the welding strips 30 from being connected to the second grid line 122, thereby avoiding the problem of short circuit.

[0080] In the embodiment of the present application, the form and preparation method of the insulating structure 50 are not limited to meet different needs. In one embodiment, the insulating structure 50 is an insulating glue layer set on the corresponding gate line by 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 cell, which can reduce the pollution and damage to the battery cell. Furthermore, the insulating glue layer can be photocured and thermally cured, and the duration of the photocuring is less than or equal to 2s.

[0081] Embodiment 4

[0082] See also Figure 1 and Figure 2 In some optional embodiments, the conductive connection structure 40 is solder paste or conductive glue or other metal conductive materials.

[0083] Thus, the conductive connection structure 40 uses easily deformable materials such as solder paste or conductive glue, which can cope with irregular accommodating spaces 31 that appear during the process of manufacturing, so as to ensure that the conductive connection structure 40 can connect the first gate line 121 and the soldering ribbon 30 together.

[0084] In the embodiment of the present application, the type of the conductive connection structure 40 is not limited to meet different needs. In one example, when the conductive connection structure 40 is solder paste, the solder paste has good wettability and fluidity, is suitable for filling irregular spaces, and ensures the stability of the electrical connection. In another example, when the conductive connection structure 40 is a conductive adhesive, the conductive adhesive has softness and good adhesion, can fit tightly between the grid line and the solder strip 30, and adapt to the accommodating space 31 of different shapes and sizes. In another example, when the conductive connection structure 40 is other metal conductive materials, the metal material has excellent conductive properties and can ensure efficient conduction of current. By utilizing the flexibility and conductivity of these materials, the current can be smoothly conducted, further improving the power generation efficiency of the back contact battery assembly 100.

[0085] Furthermore, since the solder strip 30 is stretched and set on the first battery cell 10 and the second battery cell 20 during the process preparation, irregular accommodation spaces 31 are likely to appear. When the conductive connection structure 40 uses solder paste or 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 by a simple coating or dispensing process during use, which is easy to operate and low in cost. At the same time, due to the fluidity and plasticity of the material itself, it can adapt to the irregular accommodation space 31 that appears during the preparation process, ensuring the integrity and reliability of the conductive connection structure 40.

[0086] Embodiment 5

[0087] See also Figure 1 and Figure 2 In some optional embodiments, the length of the conductive connection structure 40 along the first direction is greater than 6 mm. For example, the length of the conductive connection structure 40 along the first direction can 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, or 8 mm.

[0088] In this way, during the process preparation, the welding strip 30 can be connected to the first battery cell 10 and the second battery cell 20, and the size of the accommodating space 31 is 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.

[0089] Specifically, in the embodiment of the present application, there is no limitation on the type of the welding ribbon 30 to meet different needs. For example, the welding ribbon 30 can be a round welding ribbon 30, or a flat wide welding ribbon 30. It should be noted that when the welding ribbon 30 is arranged on the first battery cell 10 and the second battery cell 20, the length of the accommodating space 31 in the first direction will not be uniform due to process errors. The length of the accommodating space 31 in the first direction is 0.5mm-6mm, so it is only necessary that the length of the conductive connection structure 40 in the first direction is greater than 6mm. Exemplarily, the length of the conductive connection structure 40 along the first direction is 7mm, which can effectively connect the first gate line 121 and the welding ribbon 30 in the accommodating space 31 to ensure stable connection.

[0090] Embodiment 6

[0091] See also Figure 2 and Figure 3 In some optional embodiments, the thickness of the conductive connection structure 40 along the third direction is 30 μm-300 μm, wherein the third direction is perpendicular to the first direction and the second direction. For example, the thickness of the conductive connection structure 40 along the third direction can 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.

[0092] Thus, the thickness of the conductive connection structure 40 is set within this range. On the one hand, it can avoid the problem of cold solder joints and leaked solder joints caused by the conductive connection structure 40 being too thin. On the other hand, it can avoid the conductive connection structure 40 being too thick to affect the overall thickness of the back contact battery assembly 100.

[0093] Embodiment 7

[0094] See also Figure 1 and Figure 2 In some optional embodiments, in the second direction, the width of the soldering ribbon 30 is greater than the width of the conductive connection structure 40 .

[0095] In this way, the soldering tape 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 assembly 100. The exposed conductive connection structure 40 is easy to contact with other conductive components or lines, causing 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, the conductive connection structure 40 is shielded by the soldering tape 30 to prevent the conductive connection structure 40 from being pressed out and exposed when the soldering tape 30 is pressed on the conductive connection structure 40. In this way, not only the durability and reliability of the component are improved, but also the conductive connection structure 40 can be prevented from being mechanically damaged or oxidized, further improving the service life and performance stability of the back-contact battery assembly 100.

[0096] Embodiment 8

[0097] See also Figure 1 and Figure 2 In some optional embodiments, in the second direction, the width of the insulating structure 50 is greater than the width of the conductive connection structure 40 .

[0098] Thus, in the second direction, the width of the insulating structure 50 is greater than the width of the conductive connection structure 40 , so as to prevent the conductive connection structure 40 from being short-circuited with the second gate line 122 .

[0099] Specifically, the wider insulating structure 50 provides a larger physical isolation area, enhances the electrical insulation effect, and avoids possible electrical interference and current leakage. In the actual production process, process errors may cause slight deviations in the position of the conductive connection structure 40. The wider insulating structure 50 can compensate for these deviations to ensure that the insulation effect is not affected. At the same time, the wider insulating structure 50 can avoid insulation failures caused by process variation, aging, etc., and enhance the stability and reliability of the back contact battery assembly 100 during long-term use.

[0100] Embodiment 9

[0101] See also Figure 1 and Figure 2 In some optional 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, or 40 μm.

[0102] Thus, the thickness of the insulating structure 50 is set within this range, which can achieve physical isolation between the second gate line 122 and the conductive connection structure 40 , thereby ensuring insulation between the second gate line 122 and the conductive connection structure 40 .

[0103] 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 grid line 122 and the conductive connection structure 40 , and improve the overall electrical performance and reliability of the back contact battery assembly 100 .

[0104] Embodiment 10

[0105] See also Figure 5 and Figure 6 In some optional embodiments, when the back side 12 of the first battery cell 10 and the front side 11 of the second battery cell 20 are at least partially stacked together, the accommodating space 31 is formed on the back side 12 of the first battery cell 10 close to the second battery cell 20, and the welding strip 30 also includes a second welding strip 33 and a third welding strip 34. The second welding strip 33 is arranged on the back side 12 of the first battery cell 10 and at least partially extends into the back side 12 of the second battery cell 20. The third welding strip 34 is located on the back side 12 of the second battery cell 20.

[0106] In this way, the back side 12 of the first battery cell 10 and the edge portion of the front side 11 of the second battery cell 20 are stacked together, which can effectively increase the light receiving area of ​​the back contact battery assembly 100 .

[0107] Embodiment 11

[0108] See also Figure 1 and Figure 3 In some optional embodiments, the conductive connection structure 40 is formed with an inclined surface 41 on a side away from the first battery cell 10 , and the inclined surface 41 is connected to the welding ribbon 30 .

[0109] In this way, the inclined surface 41 is consistent with the inclined direction of the soldering ribbon 30 , so that the conductive connection structure 40 can better fit the soldering ribbon 30 , ensuring a stable connection between the conductive connection structure 40 and the soldering ribbon 30 .

[0110] Embodiment 12

[0111] See also Figure 5 and Figure 6 In some optional embodiments, the back contact battery assembly 100 further includes a bus bar 60, and the bus bar 60 is disposed on the back side 12 of the second battery cell 20;

[0112] The bus bar 60 is connected to the second welding ribbon 33 and is located on a side of the second welding ribbon 33 away from the second battery cell 20 ;

[0113] The bus bar 60 is connected to the second welding ribbon 33 and is located on a side of the second welding ribbon 33 close to the second battery cell 20 .

[0114] Specifically, the bus bar 60 is arranged on the side of the second welding strip 33 away from the second battery cell 20, which can avoid affecting the accommodating space 31 and the components inside the accommodating space 31. The bus bar 60 is arranged on the side of the second welding strip 33 close to the second battery cell 20, which can increase the volume of the accommodating space 31, and then the size of the conductive connection structure 40 can be reasonably adjusted to ensure stable connection.

[0115] Embodiment 13

[0116] See also Figure 7 and Figure 8 In some optional embodiments, when the front side 11 of the first battery cell 10 and the back side 12 of the second battery cell 20 are at least partially stacked together, the accommodating space 31 is formed on the back side 12 of the first battery cell 10 close to the second battery cell 20, and the welding strip 30 also includes a second welding strip 33 and a third welding strip 34. The second welding strip 33 is arranged on the back side 12 of the first battery cell 10 and at least partially extends into the back side 12 of the second battery cell 20. The third welding strip 34 is located on the back side 12 of the second battery cell 20.

[0117] See also Figure 7 and Figure 8 In some optional embodiments, the back contact battery assembly 100 further includes a bus bar 60, and the bus bar 60 is disposed on the back side 12 of the first battery cell 10;

[0118] The bus bar 60 is connected to the second welding ribbon 33 and is located on a side of the second welding ribbon 33 away from the second battery cell 20 ;

[0119] The bus bar 60 is connected to the second welding ribbon 33 and is located on a side of the second welding ribbon 33 close to the second battery cell 20 .

[0120] Specifically, the bus bar 60 is arranged on the side of the second welding strip 33 away from the second battery cell 20, which can avoid affecting the accommodating space 31 and the components inside the accommodating space 31. The bus bar 60 is arranged on the side of the second welding strip 33 close to the second battery cell 20, which can eliminate the volume of the accommodating space 31 to a certain extent, and at the same time, it can also make the lifting arc of the second welding strip 33 smaller, ensuring stable connection.

[0121] It should be noted that when the bus bar 60 is disposed between the battery cell and the second welding strip 33 , the bus bar 60 and part of the grid lines need to be insulated to avoid a short circuit at the bus bar 60 .

[0122] In addition, in the embodiment of the present application, the specific position of the bus bar 60 is not limited to meet different requirements.

[0123] Furthermore, the back-contact battery assembly 100 further includes an insulating layer 70 , which is disposed between the bus bar 60 and the third welding ribbon 34 .

[0124] It should be noted that in such a manner, a bus bar 60 and an insulating layer 70 and other components can be provided on the end of the second battery cell 20 away from the first battery cell 10, and the welding strip 30 extending from the first battery cell 10 to the side of the second battery cell 20 will make the accommodation space 31 larger. At this time, the length L of the conductive connection structure 40 along the first direction satisfies the following relationship: 0<L≤(D+d) / tanα, where α is the angle between the direction in which the welding strip 30 is lifted and the first direction, D is the thickness of the second battery cell 20 along the third direction, d is the thickness of other components along the third direction, and the third direction is perpendicular to the second direction and the first direction. At this time, the calculation of the length L of the conductive connection structure 40 along the first direction can be obtained by the thickness of the second battery cell 20 and other components such as the third welding strip 34, the bus bar 60 and the insulating layer 70 along the third direction, thereby realizing the accurate calculation of the accommodation space 31.

[0125] Embodiment 14

[0126] See also Fig. 9 and Fig.10 The photovoltaic system 300 provided in the embodiment of the present application includes the back contact battery assembly 100 of any one of the above embodiments.

[0127] 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 welding 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 distributed and arranged along a first direction, the first battery cells 10 and the second battery cells 20 are at least partially stacked together, the back sides 12 of the first battery cells 10 and the second battery cells 20 are both formed with first grid lines 121 and second grid lines 122, the first grid lines 121 and the second grid lines 122 extend along the second direction and are alternately arranged along the first direction, the first grid lines 121 and the second grid lines 122 have opposite polarities, and the welding strip 30 is arranged on the first direction. The back side 12 of a battery cell 10 extends along a first direction, and an accommodating space 31 is formed between a side of the first battery cell 10 close to the second battery cell 20 and the welding strip 30. The conductive connection structure 40 is at least partially laid in the accommodating space 31 and connects the first grid line 121 and the welding strip 30 in the accommodating space 31. The insulating structure 50 covers the second grid line 122. The insulating structure 50 is arranged in the accommodating space 31 and is located between the second grid line 122 and the welding strip 30. The length L of the conductive connection structure 40 along the first direction satisfies the following relationship: 0<L≤D / tanα, wherein α is the angle between the direction in which the welding strip 30 is lifted and the first direction, and D is the thickness of the second battery cell 20 along the third direction, and the third direction is perpendicular to the second direction and the first direction. In this way, the welding strip 30 can be connected to the first grid line 121 in the accommodating space 31 through the conductive connecting structure 40, so that the current in the accommodating 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 connecting structure 40 to avoid the problem of short circuit.

[0128] In this embodiment, the photovoltaic system 300 can be applied to photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system 300 are not limited to this, that is, the photovoltaic system 300 can be applied to all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system 300 may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple back-contact battery assemblies 100. For example, multiple back-contact battery assemblies 100 may form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter to convert it into the alternating current required by the mains power grid and then connected to the mains network to achieve solar power supply.

[0129] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0130] In addition, the above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A 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, the insulating structure covering the second gate line, the insulating structure being arranged in the accommodating space and between the second gate line and the welding strip; The length L of the conductive connection structure along the first direction satisfies the following relationship: 0<L≤D / tanα; Wherein, α is the angle between the direction in which the welding strip is lifted and the first direction, and D is the thickness of the second battery cell along the third direction, and the third direction is perpendicular to the second direction and the first direction; 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.

2. 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.

3. The back contact battery assembly according to claim 2, 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.

4. 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.

5. The back contact battery assembly according to claim 4, 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; Alternatively, 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.

6. The back contact battery assembly according to any one of claims 1 to 5, characterized in that: The insulating structure is prepared by laying or coating.

7. The back contact battery assembly according to any one of claims 1 to 5, characterized in that: The conductive connection structure is solder paste or conductive glue or other metallic conductive materials.

8. The back contact battery assembly according to any one of claims 1 to 5, characterized in that: The length of the conductive connection structure along the first direction is greater than 6 mm.

9. The back contact battery assembly according to any one of claims 1 to 5, 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.

10. The back contact battery assembly according to any one of claims 1 to 5, characterized in that: In the second direction, the width of the soldering strip is greater than the width of the conductive connection structure.

11. The back contact battery assembly according to any one of claims 1 to 5, characterized in that: In the second direction, the width of the insulating structure is greater than the width of the conductive connection structure.

12. The back contact battery assembly according to any one of claims 1 to 5, characterized in that: The thickness of the insulating structure is 25 μm-40 μm.

13. The back contact battery assembly according to any one of claims 1 to 5, 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.

14. The back contact battery assembly according to any one of claims 3 or 5, characterized in that: The back-contact battery assembly further includes an insulating layer disposed between the bus bar and the third welding ribbon.

15. The back contact battery assembly according to claim 1, characterized in that: The angle α between the lifting direction of the welding strip and the first direction is adjusted according to the yield degree of the welding strip.

16. The back contact battery assembly according to claim 15, characterized in that: The yield strength of the welding strip is adjusted to be less than or equal to 75Mpa.

17. The back contact battery assembly according to claim 1, characterized in that: The thickness D of the second battery cell along the third direction is 90 μm-200 μm.

18. A photovoltaic system, characterized in that: Comprising a back contact battery assembly as described in any one of claims 1-17.

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