Back contact solar photovoltaic module and preparation method thereof

Abstract

The invention provides a back contact solar photovoltaic module and a preparation method thereof, and belongs to the technical field of solar photovoltaic module manufacturing. The back contact solar photovoltaic module comprises a plurality of battery strings which are distributed side by side, each battery string comprises a plurality of battery pieces which are distributed at intervals, the back faces of the battery pieces are sequentially connected through a welding strip, in the extending direction of the battery strings, the welding strip comprises a non-confluence connecting area and a confluence connecting area located in the middle, the confluence connecting area is welded with a confluence strip, and the non-confluence connecting area is connected with the confluence strip. The bus bars are positioned on the back surfaces of the battery pieces, are in insulated connection with the back surfaces and are used for leading out current; in the extension direction of the battery string, the distance between any two adjacent battery pieces is 0.5-4 mm, and the tolerance is less than 0.2 mm. The back contact solar photovoltaic module has high product power.

Description

Technical Field

[0001] The present application relates to the technical field of solar photovoltaic module manufacturing, and in particular to a back-contact solar photovoltaic module and a preparation method thereof. Background Art

[0002] In the prior art, back-contact solar photovoltaic modules are usually connected using conventional half-cell circuits. Accordingly, a gap is usually reserved in the middle of the module for installing the busbar, so that the current of the module can be drawn out from here through the busbar. In order to prevent the module from short-circuiting, the busbar needs to be insulated from the two connected cells at the gap. In addition, the width of the busbar itself is also relatively large, so the gap in the busbar installation area is usually as high as 10 mm or more. This gap size is much larger than the gap between adjacent cells in the non-busbar installation area, resulting in the product power of the corresponding photovoltaic module being affected. Summary of the invention

[0003] The purpose of the present application is to provide a back-contact solar photovoltaic module and a preparation method thereof, wherein the back-contact solar photovoltaic module has a higher product power and also has the advantages of a better appearance and a more regular overall structure.

[0004] The embodiment of the present application is implemented as follows:

[0005] In the first aspect, an embodiment of the present application provides a back-contact solar photovoltaic module, comprising a plurality of battery strings arranged side by side, each battery string comprising a plurality of battery cells arranged at intervals, the back sides of the plurality of battery cells being connected in sequence by welding strips, and in the extension direction of the battery string, the welding strips comprising a non-bus connection area and a bus connection area located in the middle, the bus connection area being welded with a bus strip, the bus strip being located on the back side of the battery cell and being insulated from the back side, and the bus strip being used to lead out current; along the extension direction of the battery string, the spacing between any two adjacent battery cells is 0.5 to 4 mm, and the tolerance is less than 0.2 mm.

[0006] In the above technical solution, the bus connection area located in the middle of the battery string is welded to the bus strip located on the back of the battery cell and insulated from the corresponding battery cell. On the one hand, the basic function of the bus strip to lead out current can be normally exerted; on the other hand, by transferring the bus strip from the gap between two adjacent battery cells to the back of the battery cell, the size of the gap can be reduced, which is helpful for the reasonable layout of the battery cells, thereby improving the product power of the corresponding photovoltaic module; at the same time, the gap size between any two adjacent battery cells can be made basically the same, so that the photovoltaic module has the advantages of better appearance and more regular overall structure.

[0007] In some optional embodiments, in the extension direction of the battery string, the size of the busbar is 6 to 15 mm, and the distance between any two adjacent battery cells is 2 to 4 mm.

[0008] In the above technical scheme, when the outer frame size of the photovoltaic module remains unchanged, the distance between the two battery cells corresponding to the busbar setting area is reduced, and the distance can be evenly distributed between other two adjacent battery cells, so that the distance between any two adjacent battery cells is 2-4 mm. On the one hand, the original packaging size can be used to package the photovoltaic module without increasing the packaging cost; on the other hand, the distance between the two adjacent battery cells in other areas except the busbar setting area is more appropriate, so that the photovoltaic module has a higher cell spacing reflection power, and thus the photovoltaic module has a higher product power.

[0009] In some optional embodiments, in the extension direction of the battery string, the size of the busbar is 6-15 mm, and the spacing between any two adjacent battery cells is 0.5-1 mm.

[0010] In the above technical solution, the spacing between the two battery cells corresponding to the area where the busbar is set is reduced, and the spacing between the two battery cells at the busbar can be adjusted to be consistent with the spacing between the two battery cells in other areas, specifically 0.5 to 1 mm. Under the condition that the total power remains unchanged, the size of the photovoltaic module is reduced, thereby increasing the power per unit area (that is, the product conversion efficiency is improved); at the same time, the reduction in the overall size of the photovoltaic module also helps to reduce the preparation consumables of the module, thereby reducing the manufacturing cost of the module.

[0011] In some optional embodiments, the bus strap is located on the side of the bus connection area away from the battery cell, and an insulating film is installed between the bus connection area and the corresponding two adjacent battery cells. In the extension direction of the battery string, both ends of the insulating film extend to the back sides of the corresponding battery cells respectively, and in the thickness direction of the battery cells, the orthographic projection of the bus strap is located within the orthographic projection of the insulating film, so that the bus strap is insulated and connected to the back sides of the battery cells in the corresponding area.

[0012] In the above technical solution, the busbar is arranged on the side of the welding strip away from the battery cell, and an insulating film is arranged between the welding strip and the battery cell in the corresponding area. Specifically, in the extension direction of the battery string, the two ends of the insulating film respectively extend to the back side of the corresponding battery cell, and in the thickness direction of the battery cell, the orthographic projection of the busbar is located within the orthographic projection of the insulating film. The busbar is arranged in this way so that the busbar is located at the outermost side, so as to facilitate the current to be drawn out from there.

[0013] In some optional embodiments, the insulating film includes an insulating layer and a buffer layer which are stacked and distributed, the insulating layer is located on a side close to the bus connection area, and the buffer layer is located on a side close to the battery cell, and in the extension direction of the battery string, both ends of the buffer layer extend to the back sides of the corresponding battery cells respectively, and in the thickness direction of the battery cell, the orthographic projection of the bus strip is located within the orthographic projection of the insulating layer.

[0014] In the above technical solution, the insulating film is arranged in a form in which an insulating layer and a buffer layer cooperate with each other. Specifically, the insulating layer is located on the side close to the bus connection area, and the buffer layer is located on the side close to the battery cell. In the extension direction of the battery string, the two ends of the buffer layer extend to the back sides of the corresponding battery cells respectively. In the thickness direction of the battery cell, the orthographic projection of the bus strip is located within the orthographic projection of the insulating layer. This arrangement can play a buffering role in the subsequent component lamination process, thereby improving the problem of chip cracking.

[0015] In some optional embodiments, the width of the insulating layer is 8 to 30 mm, the thickness of the insulating layer is 0.05 to 0.15 mm; and / or the thickness of the buffer layer is 0.1 to 0.6 mm.

[0016] In the above technical scheme, the width of the insulating layer is limited within a specific range, which can be compatible with various commonly used width specifications of busbars at this stage; the thickness of the insulating layer is limited within a specific range, which can take into account both good insulation effect and low manufacturing cost; the thickness of the buffer layer is limited within a specific range, which can take into account both good buffering effect and low manufacturing cost.

[0017] In some optional embodiments, the bus strap includes a stacked bus strap body and an insulating film, the bus strap is located between the bus strap connection area and the battery cells in the corresponding area, the side of the bus strap connection area close to the battery cell is electrically connected to the side of the bus strap body facing away from the insulating film, in the extension direction of the battery string, the two ends of the insulating film respectively extend to the back side of the corresponding battery cell, and in the thickness direction of the battery cell, the orthographic projection of the bus strap body is located within the orthographic projection of the insulating film, so that the bus strap body is insulated and connected to the back side of the battery cell in the corresponding area.

[0018] In the above technical solution, the bus strip is arranged in the form of a bus strip body and an insulating film that are stacked and distributed, that is, the bus conductive function and the insulating function are integrated on the bus strip at the same time. Specifically, the bus strip body is used to electrically connect with the bus connection area of ​​the welding strip. In the extension direction of the battery string, the two ends of the insulating film extend to the back of the corresponding battery cell respectively, and in the thickness direction of the battery cell, the orthographic projection of the bus strip body is located within the orthographic projection of the insulating film to achieve insulation between the bus strip body and the battery cell. This type of setting of the bus strip has the advantage of fewer process steps in the process of component assembly, and can improve the preparation efficiency of the photovoltaic component itself.

[0019] In some optional embodiments, the insulating film includes a stacked insulating layer and a buffer layer, the insulating layer is located between the busbar body and the buffer layer, and in the extension direction of the battery string, both ends of the insulating layer extend to the back sides of the corresponding battery cells respectively, and in the thickness direction of the battery cell, the orthographic projection of the busbar body is located within the orthographic projection of the insulating layer.

[0020] In the above technical solution, the insulating film is arranged in a form in which an insulating layer and a buffer layer cooperate with each other. Specifically, the insulating layer is located between the busbar body and the buffer layer. In the extension direction of the battery string, the two ends of the buffer layer extend to the back sides of the corresponding battery cells respectively. In the thickness direction of the battery cell, the orthographic projection of the busbar is located within the orthographic projection of the insulating layer to achieve insulation between the busbar body and the battery cell. This arrangement can play a buffering role in the subsequent component lamination process, thereby improving the problem of chip cracking.

[0021] In the second aspect, the embodiment of the present application provides a method for preparing a back-contact solar photovoltaic module as provided in the embodiment of the first aspect, comprising the following steps: assembling in the order of placing a lower glass plate or a lower back plate, an adhesive film, a power generation unit, an adhesive film, and an upper glass plate from bottom to top, and finally laminating to obtain a back-contact solar photovoltaic module; comprising a plurality of battery strings distributed side by side, each battery string comprising a plurality of spaced-apart battery cells, the spacing between any two adjacent battery cells being 0.5 to 4 mm, and the tolerance being less than 0.01 mm, the back sides of the plurality of battery cells being connected in sequence by welding strips, and in the extension direction of the battery string, the welding strips comprising a non-bus connection area and a bus connection area located in the middle, the bus connection area being welded with a bus strip, the bus strip being located on the back side of the battery cell and being insulated from the back side, and the bus strip being used to lead out current.

[0022] By using a power generation unit with a specific structure and preparing it according to the above process, a back-contact solar photovoltaic module with higher product power, better appearance and more regular overall structure can be produced.

[0023] In some optional embodiments, the method of forming the spaced battery cells includes arranging a plurality of battery cells evenly at intervals while keeping the outer circumferential size of the power generation unit unchanged, so that the spacing between any two adjacent battery cells is 2 to 4 mm; or, setting the spacing between two adjacent battery cells at the busbar to be consistent with the spacing between other two adjacent battery cells, and both are 0.5 to 1 mm.

[0024] In the above technical solution, the two different ways of forming the battery cells have the corresponding photovoltaic modules having the advantages of relatively excellent product power and relatively excellent product conversion efficiency respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the installation structure of the existing busbar in the middle gap of the battery string;

[0027] Figure 2 A schematic structural diagram of the front side of a power generation unit of a back-contact solar photovoltaic module provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of the installation structure of the first busbar provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of the installation structure of the second busbar provided in an embodiment of the present application.

[0030] Icon: 10-back contact solar photovoltaic module; 100-cell string; 110-cell; 111-back side; 120-solder strip; 121-bus connection area; 122-non-bus connection area; 130-bus strip; 131-bus strip body; 140-insulating film; 141-insulating layer; 142-buffer layer; a-extension direction of the cell string. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0034] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0035] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" 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 direct connection, or an indirect connection through an intermediate medium, or it can be a connection between the 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.

[0036] In the prior art, in the back contact solar photovoltaic module, the arrangement of the busbar in the middle of the module can be referred to Figure 1 Specifically, there is a gap of more than 10 mm between two adjacent battery cells 110 located in the middle of the battery string. The busbar 130 is located in the gap and welded to the welding strip 120 in this area but is insulated from the two adjacent battery cells 110 so as to lead the current out from there. The gap size is much larger than the gap between adjacent battery cells 110 in the non-busbar 130 installation area, thereby affecting the reasonable arrangement of the battery cells and affecting the product power of the corresponding photovoltaic module.

[0037] The inventors have found that without changing the existing circuit structure and main frame structure of the back-contact solar photovoltaic module, only by optimizing the setting of the middle busbar 130 (i.e., adjusting the busbar 130 from the gap to the back of the battery cell 110), the size of the middle gap can be greatly reduced while ensuring the normal operation of the module, which helps to reasonably arrange the battery cell 110 so that the photovoltaic module has a higher product power.

[0038] The following is a detailed description of a back-contact solar photovoltaic module and a preparation method thereof provided in the present application.

[0039] See also Figure 2 and Figure 3 (It should be noted that Figure 3In the embodiment, there is a gap between the welding ribbon 120 and the back side 111 of the battery cell 110 because there is a protruding welding point of the welding ribbon 120 in the non-central area). The embodiment of the present application provides a back-contact solar photovoltaic module 10, including a plurality of battery strings 100 arranged side by side, each battery string 100 includes a plurality of battery cells 110 arranged at intervals, and the back sides 111 of the plurality of battery cells 110 are connected in sequence through the welding ribbon 120. In the extension direction a of the battery string, the welding ribbon 120 includes a non-bus connection area 122 and a bus connection area 121 located in the middle, and the bus connection area 121 is welded with a bus ribbon 130, which is located on the back side 111 of the battery cell 110 and is insulated from the back side 111, and the bus ribbon 130 is used to lead out current; along the extension direction a of the battery string, the spacing between any two adjacent battery cells 110 is 0.5-4 mm, and the tolerance is less than 0.2 mm.

[0040] In the present application, the bus connection area 121 of the welding strip 120 located in the middle of the battery string 100 is welded to the bus strip 130 located on the back side 111 of the battery cell 110 and insulated from the corresponding battery cell 110. On the one hand, the basic function of the bus strip 130 for current extraction can be normally exerted; on the other hand, by transferring the bus strip 130 from the gap between two adjacent battery cells 110 to the back side 111 of the battery cell 110, the size of the gap can be reduced, which is helpful for the reasonable layout of the battery cells 110, thereby improving the product power of the corresponding photovoltaic module; at the same time, the gap size between any two adjacent battery cells 110 can be made basically the same, so that the photovoltaic module has the advantages of better appearance and more regular overall structure.

[0041] It should be noted that a plurality of battery strings 100 arranged side by side usually act as a power generation unit as a whole in a photovoltaic module. Accordingly, the photovoltaic module also has basic functional units such as a lower glass plate or a lower back plate, a back film, a front film and an upper glass plate.

[0042] It should be noted that the insulating connection method between the busbar 130 and the back surface 111 of the battery cell 110 is not limited and can be adaptively adjusted according to actual needs. Two insulating connection methods of the busbar 130 are introduced below as examples for auxiliary explanation.

[0043] The first busbar connection method, see Figure 3The bus strip 130 is located on the side of the bus connection area 121 away from the battery cell 110, and an insulating film 140 is installed between the bus connection area 121 and the corresponding two adjacent battery cells 110. In the extension direction a of the battery string, the two ends of the insulating film 140 extend to the back side 111 of the corresponding battery cell 110 respectively, and in the thickness direction of the battery cell 110, the orthographic projection of the bus strip 130 is located within the orthographic projection of the insulating film 140, so that the bus strip 130 is insulated and connected to the back side 111 of the battery cell 110 in the corresponding area.

[0044] It should be noted that “the orthographic projection of the busbar 130 is located within the orthographic projection of the insulating film 140 ”, so that the busbar and the back surface 111 of the battery cell 110 are completely separated by the insulating film 140 , thereby preventing a short circuit.

[0045] In this embodiment, the busbar 130 is arranged on the side of the welding strip 120 away from the battery cell 110, and an insulating film 140 is arranged between the welding strip 120 and the battery cell 110 in the corresponding area. Specifically, in the extension direction a of the battery string, the two ends of the insulating film 140 respectively extend to the back side 111 of the corresponding battery cell 110, and in the thickness direction of the battery cell 110, the orthographic projection of the busbar 130 is located within the orthographic projection of the insulating film 140. The busbar 130 is arranged in this way so that the busbar 130 is located at the outermost side, thereby facilitating the current to be drawn out therefrom.

[0046] See also Figure 3 As an example, the insulating film 140 includes an insulating layer 141 and a buffer layer 142 which are stacked and distributed. The insulating layer 141 is located on a side close to the bus connection area 121, and the buffer layer 142 is located on a side close to the battery cell 110. In the extension direction a of the battery string, both ends of the buffer layer 142 extend to the back side 111 of the corresponding battery cell 110 respectively, and in the thickness direction of the battery cell 110, the orthographic projection of the bus strip 130 is located within the orthographic projection of the insulating layer 141.

[0047] In this embodiment, the insulating film 140 is configured in the form of an insulating layer 141 and a buffer layer 142 that cooperate with each other. Specifically, the insulating layer 141 is located on the side close to the bus connection area 121, and the buffer layer 142 is located on the side close to the battery cell 110. In the extension direction a of the battery string, both ends of the buffer layer 142 extend to the back side 111 of the corresponding battery cell 110 respectively. In the thickness direction of the battery cell 110, the orthographic projection of the bus strip 130 is located within the orthographic projection of the insulating layer 141. This configuration can play a buffering role in the subsequent component lamination process, thereby improving the problem of chip splitting.

[0048] As an example, the width of the insulating layer 141 is 8 to 30 mm, for example but not limited to a width of any point value of 8 mm, 10 mm, 15 mm, 20 mm, 25 mm and 30 mm, or a range value between any two of them; and / or, the thickness of the insulating layer 141 is 0.05 to 0.15 mm, for example but not limited to a thickness of any point value of 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.10 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm and 0.15 mm, or a range value between any two of them.

[0049] In this embodiment, the width of the insulating layer 141 is limited within a specific range, which can be compatible with various commonly used busbars 130 of width specifications at this stage; the thickness of the insulating layer 141 is limited within a specific range, which can take into account both good insulation effect and low manufacturing cost.

[0050] As an example, the thickness of the buffer layer 142 is 0.1-0.6 mm, for example but not limited to any one of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm and 0.6 mm or a range between any two of the thicknesses.

[0051] In this embodiment, the thickness of the buffer layer 142 is limited to a specific range, which can achieve both a good buffering effect and a low manufacturing cost.

[0052] It should be noted that the width of the buffer layer 142 is not limited, for example, the width may be 8 to 30 mm, which is the same as the width of the insulating layer 141 .

[0053] See also Figure 3 As an example, in the extension direction a of the battery string, the size of the insulating film 140 on the back sides 111 of two adjacent battery cells 110 is the same, that is, the insulating film 140 is symmetrically arranged about the corresponding gap.

[0054] The second busbar connection method, see Figure 4 The bus strip 130 includes a stacked bus strip body 131 and an insulating film 140. The bus strip 130 is located between the bus connection area 121 and the battery cell 110 in the corresponding area. The side of the bus connection area 121 close to the battery cell 110 is electrically connected to the side of the bus strip body 131 away from the insulating film 140. In the extension direction a of the battery string, the two ends of the insulating film 140 extend to the back side 111 of the corresponding battery cell 110 respectively, and in the thickness direction of the battery cell 110, the orthographic projection of the bus strip body 131 is located within the orthographic projection of the insulating film 140, so that the bus strip body 131 is insulated and connected to the back side 111 of the battery cell 110 in the corresponding area.

[0055] In this embodiment, the bus strip 130 is configured to be in the form of a bus strip body 131 and an insulating film 140 that are stacked and distributed, that is, the bus conductive function and the insulating function are integrated on the bus strip 130 at the same time. Specifically, the bus strip body 131 is used to electrically connect with the bus connection area 121 of the welding strip 120. In the extension direction a of the battery string, the two ends of the insulating film 140 extend to the back side 111 of the corresponding battery cell 110 respectively, and in the thickness direction of the battery cell 110, the orthographic projection of the bus strip body 131 is located within the orthographic projection of the insulating film 140 to achieve insulation between the bus strip body 131 and the battery cell 110. The bus strip 130 with this configuration has the advantage of fewer process steps during the component assembly process, and can improve the preparation efficiency of the photovoltaic component itself.

[0056] See also Figure 4 As an example, the insulating film 140 includes an insulating layer 141 and a buffer layer 142 which are stacked and distributed. The insulating layer 141 is located between the busbar body 131 and the buffer layer 142. In the extension direction a of the battery string, both ends of the insulating layer 141 extend to the back side 111 of the corresponding battery cell 110 respectively, and in the thickness direction of the battery cell 110, the orthographic projection of the busbar body 131 is located within the orthographic projection of the insulating layer 141.

[0057] In this embodiment, the insulating film 140 is configured in the form of an insulating layer 141 and a buffer layer 142 that cooperate with each other. Specifically, the insulating layer 141 is located between the busbar body 131 and the buffer layer 142. In the extension direction a of the battery string, both ends of the buffer layer 142 extend to the back side 111 of the corresponding battery cell 110 respectively. In the thickness direction of the battery cell 110, the orthographic projection of the busbar 130 is located within the orthographic projection of the insulating layer 141 to achieve insulation between the busbar body 131 and the battery cell 110. This configuration can play a buffering role in the subsequent component lamination process, thereby improving the problem of chip splitting.

[0058] It should be noted that the parameter dimensions of the insulating layer 141 and the buffer layer 142 may refer to the first insulation setting method of the busbar 130 .

[0059] Based on the aforementioned connection method of the busbar 130 , the present application further improves the arrangement of the battery cells 110 , and two arrangement methods are specifically described below.

[0060] The first type of photovoltaic module: The inventors have found that in the process of photovoltaic modules using solar energy to generate electricity, the product power of the photovoltaic modules depends to a certain extent on the reflected power of the inter-chip spacing, and the reflected power of the inter-chip spacing is closely related to the size of the inter-chip spacing. Based on this, the size of the inter-chip spacing can be optimized.

[0061] Specifically in the present application, the gap between the two battery cells 110 in the installation area of ​​the existing busbar 130 is usually more than 10 mm. The present application provides a new connection method for the busbar 130, which can reduce the gap. When the outer frame size of the power generation unit remains unchanged, the reduced gap is evenly distributed between other adjacent battery cells 110, so that the distance between any two adjacent battery cells 110 is 2 to 4 mm.

[0062] As an example, in the extension direction a of the battery string, the size of the busbar 130 is 6 to 15 mm, for example but not limited to any point value of 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm and 15 mm, or a range value between any two of them; the spacing between any two adjacent battery cells 110 is 2 to 4 mm, for example but not limited to any point value of 2 mm, 2.5 mm, 3 mm, 3.5 mm and 4 mm, or a range value between any two of them.

[0063] In this embodiment, when the outer frame size of the photovoltaic module remains unchanged, the spacing between the two battery cells 110 corresponding to the area where the busbar 130 is set is reduced, and the spacing can be evenly distributed between other two adjacent battery cells 110, so that the spacing between any two adjacent battery cells 110 is 2-4 mm. On the one hand, the original packaging size can be used to package the photovoltaic module without increasing the packaging cost. On the other hand, the spacing between the two adjacent battery cells 110 in other areas except the area where the busbar 130 is set is more appropriate, so that the photovoltaic module has a higher cell spacing reflection power, and thus the photovoltaic module has a higher product power.

[0064] For the second type of photovoltaic module, in the prior art, the spacing between two battery cells 110 in the installation area of ​​the busbar 130 is usually more than 10 mm. The present application provides a new connection method for the busbar 130, which can reduce the gap and adjust the gap to be consistent with the spacing between other two adjacent battery cells 110, both of which are 0.5 to 1 mm. Under the condition of unchanged total power, the size of the photovoltaic module is reduced, thereby increasing the power per unit area (that is, the product transfer efficiency is improved).

[0065] As an example, in the extension direction a of the battery string, the size of the busbar 130 is 6 to 15 mm, for example but not limited to any point value of 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm and 15 mm, or a range value between any two of them; the spacing between any two adjacent battery cells 110 is 0.5 to 1 mm, for example but not limited to any point value of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1 mm, or a range value between any two of them.

[0066] In this embodiment, the spacing between the two battery cells 110 corresponding to the area where the busbar 130 is set is reduced, and the spacing between the two battery cells 110 at the busbar 130 can be adjusted to be consistent with the spacing between the two battery cells 110 in other areas, specifically 0.5 to 1 mm. Under the condition of unchanged total power, the size of the photovoltaic module is reduced, thereby increasing the power per unit area (i.e., improving the product conversion efficiency); at the same time, the reduction in the overall size of the photovoltaic module also helps to reduce the preparation consumables of the module, thereby reducing the manufacturing cost of the module.

[0067] It should be noted that any structure or functional unit not specifically described in the back-contact solar photovoltaic module 10 may be configured according to conventional selections in the art. The preparation method of the photovoltaic module provided above is described below.

[0068] The embodiment of the present application provides a method for preparing a back-contact solar photovoltaic module, comprising the following steps: assembling by placing a lower glass plate or a lower back plate, an adhesive film, a power generation unit, an adhesive film, and an upper glass plate in order from bottom to top, and finally laminating to obtain a back-contact solar photovoltaic module; comprising a plurality of battery strings arranged side by side, each battery string comprising a plurality of battery cells arranged at intervals, the spacing between any two adjacent battery cells being 0.5 to 4 mm, and the tolerance being less than 0.2 mm, the back sides of the plurality of battery cells being connected in sequence by welding strips, in the extension direction of the battery string, the welding strips comprising a non-bus connection area and a bus connection area located in the middle, the bus connection area being welded with a bus strip, the bus strip being located on the back side of the battery cell and being insulated from the back side, the bus strip being used to lead out current.

[0069] By using a power generation unit with a specific structure and preparing it according to the above process, a back-contact solar photovoltaic module with higher product power, better appearance and more regular overall structure can be produced.

[0070] It should be noted that when a lower glass plate is used in the component, the corresponding component is a double-glass component, that is, double-sided power generation; when a lower back plate is used in the component, the corresponding component is a single-glass component, that is, single-sided power generation.

[0071] As an example, the method of forming the spaced battery cells includes arranging a plurality of battery cells evenly at intervals while keeping the outer circumferential size of the power generation unit unchanged, so that the spacing between any two adjacent battery cells is 2 to 4 mm; or, setting the spacing between two adjacent battery cells at the busbar to be consistent with the spacing between other two adjacent battery cells, and both are 0.5 to 1 mm.

[0072] In this embodiment, two different ways of forming the battery cells correspond to forming photovoltaic modules with two different gap specifications.

[0073] It should be noted that the specific assembly process of the power generation unit is not limited, and any process method that can form the specific structure is applicable.

[0074] Specifically in the present application, two photovoltaic modules with different gap specifications are taken as an example.

[0075] The first type of photovoltaic module has a spacing between any two adjacent cells of 2 to 4 mm.

[0076] The spacing between any two adjacent cells of the second photovoltaic module is 0.5 to 1 mm.

[0077] In order to better understand the technical solution, several feasible processes are combined here to provide auxiliary explanations of the assembly processes of the first photovoltaic module and the second photovoltaic module.

[0078] The first photovoltaic module assembly process is as follows:

[0079] The first assembly process: while keeping the outer circumferential size of the power generation unit unchanged, multiple battery cells are evenly spaced so that the spacing between any two adjacent battery cells is 2 to 4 mm, and multiple equally spaced battery cells are sequentially connected through welding strips to obtain a battery string; multiple battery strings are arranged side by side, and then the busbar area of ​​the welding strip located in the middle of the battery string is electrically connected to the busbar arranged on the back of the battery cell and insulated from the battery cell to obtain a power generation unit.

[0080] It should be noted that there are two methods for "electrically connecting the busbar area located in the middle of the battery string with the busbar disposed on the back of the battery cell and insulated from the battery cell". Figure 3 and Figure 4 First, see Figure 3 , corresponding to the form of separate setting of the insulating film and the busbar, first place the insulating film in the gap between the welding ribbon and the back of the battery cell, and then place the independent busbar on the side of the welding ribbon away from the battery cell; second, refer to Figure 4, corresponding to the single-sided insulated busbar form, the busbar is directly placed in the gap between the welding ribbon and the back of the battery cell, with the conductive side of the busbar facing the welding ribbon and the insulating side of the busbar facing the back of the battery cell.

[0081] The second assembly process: while keeping the outer circumferential size of the power generation unit unchanged, multiple cells are laid out in an array according to the specifications of the photovoltaic module (for example, six columns, with 40 cells in each column), and the spacing between any two adjacent cells in each column is 2 to 4 mm, to obtain a power generation unit precursor.

[0082] It should be noted that since there are two ways to connect the busbar insulation, there are also two ways to assemble the power generation unit from the power generation unit precursor. Figure 3 and Figure 4 First, see Figure 3 , according to the extension direction of each column, lay the insulating film to the middle of the power generation unit precursor, and then connect the multiple cells in each column in sequence through the welding tape, so that the insulating film is located between the cell and the welding tape of the corresponding area, and then place the busbar on the side of the welding tape away from the cell to obtain the power generation unit. Second, refer to Figure 4 , according to the extension direction of each column, a single-sided insulated busbar is laid to the middle of the power generation unit precursor, and then multiple battery cells in each column are connected in sequence through welding tapes, so that the insulating film is located between the battery cell and the welding tape of the corresponding area, wherein the conductive side of the busbar faces the welding tape, and the insulating side of the busbar faces the back of the battery cell, to obtain a power generation unit.

[0083] The second photovoltaic module assembly process is as follows:

[0084] The first assembly process: the spacing between two adjacent battery cells at the busbar is set to be consistent with the spacing between other two adjacent battery cells, and both are 0.5-1 mm, and multiple battery cells with equal spacing are connected in sequence through welding strips to obtain battery strings; multiple battery strings are arranged side by side, and then the busbar area where the welding strip is located in the middle of the battery string is electrically connected to the busbar arranged on the back of the battery cell and insulated from the battery cell to obtain a power generation unit.

[0085] It should be noted that there are two methods for "electrically connecting the busbar area located in the middle of the battery string with the busbar disposed on the back of the battery cell and insulated from the battery cell". Figure 3 and Figure 4 First, see Figure 3 , corresponding to the form of separate setting of the insulating film and the busbar, first place the insulating film in the gap between the welding ribbon and the back of the battery cell, and then place the independent busbar on the side of the welding ribbon away from the battery cell; second, refer to Figure 4, corresponding to the single-sided insulated busbar form, the busbar is directly placed in the gap between the welding ribbon and the back of the battery cell, with the conductive side of the busbar facing the welding ribbon and the insulating side of the busbar facing the back of the battery cell.

[0086] The second assembly process: laying out multiple cells in an array according to the specifications of the photovoltaic module (for example, six columns, with 40 cells in each column), and making the distance between any two adjacent cells 0.5 to 1 mm, to obtain a power generation unit precursor.

[0087] It should be noted that since there are two ways to connect the busbar insulation, there are also two ways to assemble the power generation unit from the power generation unit precursor. Figure 3 and Figure 4 First, see Figure 3 , according to the extension direction of each column, lay the insulating film to the middle of the power generation unit precursor, and then connect the multiple cells in each column in sequence through the welding tape, so that the insulating film is located between the cell and the welding tape of the corresponding area, and then place the busbar on the side of the welding tape away from the cell to obtain the power generation unit. Second, refer to Figure 4 , according to the extension direction of each column, a single-sided insulated busbar is laid to the middle of the power generation unit precursor, and then multiple battery cells in each column are connected in sequence through welding tapes, so that the insulating film is located between the battery cell and the welding tape of the corresponding area, wherein the conductive side of the busbar faces the welding tape, and the insulating side of the busbar faces the back of the battery cell, to obtain a power generation unit.

[0088] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, 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 solar photovoltaic module, characterized in that: It comprises a plurality of battery strings arranged side by side, each of the battery strings comprises a plurality of battery cells arranged at intervals, the back sides of the plurality of battery cells are connected in sequence by welding strips, in the extension direction of the battery string, the welding strips comprise a non-bus connection area and a bus connection area located in the middle, the bus connection area is welded with a bus strip, the bus strip is located on the back side of the battery cell and is insulated from the back side, and the bus strip is used to lead out current; along the extension direction of the battery string, the spacing between any two adjacent battery cells is 0.5 to 4 mm, and the tolerance is less than 0.2 mm.

2. The back contact solar photovoltaic module according to claim 1, characterized in that: In the extension direction of the battery string, the size of the busbar is 6-15 mm, and the distance between any two adjacent battery cells is 2-4 mm.

3. The back contact solar photovoltaic module according to claim 1, characterized in that: In the extension direction of the battery string, the size of the busbar is 6-15 mm, and the distance between any two adjacent battery cells is 0.5-1 mm.

4. The back-contact solar photovoltaic module according to any one of claims 1 to 3, characterized in that: The bus strap is located on the side of the bus connection area away from the battery cell, and an insulating film is installed between the bus connection area and the corresponding two adjacent battery cells. In the extension direction of the battery string, the two ends of the insulating film respectively extend to the back sides of the corresponding battery cells, and in the thickness direction of the battery cells, the orthographic projection of the bus strap is located within the orthographic projection of the insulating film, so that the bus strap is insulated and connected to the back sides of the battery cells in the corresponding area.

5. The back contact solar photovoltaic module according to claim 4, characterized in that: The insulating film includes an insulating layer and a buffer layer which are stacked and distributed, the insulating layer is located on a side close to the bus connection area, and the buffer layer is located on a side close to the battery cell. In the extension direction of the battery string, both ends of the buffer layer extend to the back sides of the corresponding battery cells respectively, and in the thickness direction of the battery cell, the orthographic projection of the bus strip is located within the orthographic projection of the insulating layer.

6. The back contact solar photovoltaic module according to claim 5, characterized in that: The width of the insulating layer is 8 to 30 mm, and the thickness of the insulating layer is 0.05 to 0.15 mm; And / or, the thickness of the buffer layer is 0.1-0.6 mm.

7. The back-contact solar photovoltaic module according to any one of claims 1 to 3, characterized in that: The bus strip includes a stacked bus strip body and an insulating film, wherein the bus strip is located between the bus connection area and the battery cells in the corresponding area, and a side of the bus connection area close to the battery cells is electrically connected to a side of the bus strip body facing away from the insulating film. In the extension direction of the battery string, both ends of the insulating film extend to the back sides of the corresponding battery cells respectively, and in the thickness direction of the battery cells, the orthographic projection of the bus strip body is located within the orthographic projection of the insulating film, so that the bus strip body is insulated and connected to the back sides of the battery cells in the corresponding area.

8. The back contact solar photovoltaic module according to claim 7, characterized in that: The insulating film includes an insulating layer and a buffer layer which are stacked and distributed. The insulating layer is located between the busbar body and the buffer layer. In the extension direction of the battery string, both ends of the insulating layer extend to the back sides of the corresponding battery cells respectively, and in the thickness direction of the battery cell, the orthographic projection of the busbar body is located within the orthographic projection of the insulating layer.

9. A method for preparing a back-contact solar photovoltaic module according to any one of claims 1 to 8, characterized in that: The following steps are involved: The lower glass plate or lower back plate, the adhesive film, the power generation unit, the adhesive film, and the upper glass plate are assembled in the order of placing them from bottom to top, and finally laminating them to obtain the back contact solar photovoltaic module; Wherein, the power generation unit includes a plurality of battery strings arranged side by side, each of the battery strings includes a plurality of battery cells arranged at intervals, the spacing between any two adjacent battery cells is 0.5 to 4 mm, and the tolerance is less than 0.01 mm, the back sides of the plurality of battery cells are connected in sequence by welding strips, in the extension direction of the battery string, the welding strips include a non-bus connection area and a bus connection area located in the middle, the bus connection area is welded with a bus strip, the bus strip is located on the back side of the battery cell and is insulated from the back side, and the bus strip is used to lead out current.

10. The method for preparing a back contact solar photovoltaic module according to claim 9, characterized in that: The method for forming the spaced-apart battery cells includes: When the outer circumference size of the power generation unit remains unchanged, a plurality of battery cells are evenly spaced so that the spacing between any two adjacent battery cells is 2 to 4 mm; Alternatively, the spacing between two adjacent battery cells at the busbar is set to be consistent with the spacing between other two adjacent battery cells, and both are 0.5 to 1 mm.

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