Manufacturing method of battery string, manufacturing method of photovoltaic module and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a manufacturing method of a battery string, a manufacturing method of a photovoltaic module and the photovoltaic module, and the manufacturing method of the battery string comprises the steps: providing an initial battery piece; segmenting the initial battery piece to form at least three segmented battery pieces; a buffer adhesive film is laid on the surface of the end part, close to the adjacent split battery piece, of each split battery piece; carrying out thermal fixation treatment, which comprises the following steps: heating the buffer adhesive film so as to enable the buffer adhesive film to be adhered to the surface of the fragmented battery piece; a welding strip is provided, the welding strip is electrically connected with the at least two fragmented battery pieces so as to connect the adjacent fragmented battery pieces in series, the adjacent fragmented battery pieces are partially overlapped, and the welding strip covers the buffer adhesive film on the surfaces of the fragmented battery pieces; and laser welding is carried out, and the laser welding comprises the steps that laser is controlled to irradiate the surface of the welding strip, so that the welding strip is welded to the surface of the fragmented battery piece. The reliability of the formed battery string can be improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the photovoltaic field, and in particular to a method for manufacturing a battery string, a method for manufacturing a photovoltaic module, and a photovoltaic module. Background Art

[0002] A battery string is a structure that connects multiple battery cells in series to output greater power. The battery string can avoid the situation where the voltage and current provided by a single battery cell cannot meet the power demand.

[0003] For battery strings, laminated battery strings are a type of battery string. After the battery sheets are cut, the front edge of the previous battery is connected to the back edge of the next battery. This design allows the battery sheets to be connected to each other in a more compact manner, and the gap between the batteries is reduced, which can increase the power of the battery string per unit area, so it is widely used.

[0004] However, for the laminated battery string, there is a problem that the overlapping parts of the laminated battery string are easily damaged. Summary of the invention

[0005] The embodiments of the present disclosure provide a method for manufacturing a battery string, a method for manufacturing a photovoltaic module, and a photovoltaic module, which can at least improve the reliability of the battery string.

[0006] According to some embodiments of the present disclosure, on the one hand, the embodiments of the present disclosure provide a method for manufacturing a battery string, comprising: providing an initial battery cell; slicing the initial battery cell to form at least 3 sliced ​​battery cells; laying a buffer adhesive film on the end surface of the sliced ​​battery cell close to the adjacent sliced ​​battery cell; performing a heat fixing treatment, the heat fixing treatment comprising: heating the buffer adhesive film to make the buffer adhesive film adhere to the surface of the sliced ​​battery cell; providing a welding strip, the welding strip is electrically connected to at least two of the sliced ​​battery cells to connect adjacent sliced ​​battery cells in series, wherein adjacent sliced ​​battery cells partially overlap, and the welding strip covers the buffer adhesive film on the surface of the sliced ​​battery cell; performing laser welding, the laser welding comprising: controlling the laser to irradiate the surface of the welding strip to weld the welding strip to the surface of the sliced ​​battery cell.

[0007] In some embodiments, the process parameters of the thermal fixing treatment include: a heating temperature of 60 to 70° C. and a heating time of 0.5 to 1.5 s.

[0008] In some embodiments, the sliced ​​cell sheets include edge cell sheets having a cutting surface, and before connecting adjacent sliced ​​cell sheets in series, the further step includes: adjusting the orientation of the cutting surfaces of the edge cell sheets so that the cutting surfaces of the edge cell sheets are oriented in the same direction.

[0009] In some embodiments, the method of laying the buffer film includes: providing an initial buffer film after adjusting the orientation of the cut surface of the edge battery cell; cutting the initial buffer film to form the buffer film, and moving the buffer film to the end surface of the sliced ​​battery cell.

[0010] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a method for manufacturing a photovoltaic module, including: providing a plurality of battery strings, each battery string including a plurality of sliced ​​battery cells, and a first welding strip connecting the plurality of sliced ​​battery cells in series; laying a second buffer adhesive film on the surfaces of the sliced ​​battery cells on both sides of the battery string, the second buffer adhesive film being located at the ends of the sliced ​​battery cells; providing a second welding strip, the second welding strip being electrically connected to the sliced ​​battery cells on both sides of the battery string, and the second welding strip covering the surface of the second buffer adhesive film; providing a bus bar, the bus bar being electrically connected to the second welding strip, so as to be electrically connected to the plurality of battery strings through the second welding strip; forming a packaging adhesive film, the packaging adhesive film being used to cover the surface of the battery string; forming a cover plate, the cover plate being used to cover the surface of the packaging adhesive film away from the battery string.

[0011] According to some embodiments of the present disclosure, the embodiments of the present disclosure further provide a photovoltaic module on the other hand, including: a battery string, the battery string including: a plurality of sliced ​​battery cells; a buffer film, the buffer film is located at the end surface of the sliced ​​battery cell close to the adjacent sliced ​​battery cell; a welding strip, the welding strip is electrically connected to at least two of the sliced ​​battery cells to connect adjacent sliced ​​battery cells in series, the adjacent sliced ​​battery cells partially overlap, and the welding strip covers the buffer film on the surface of the sliced ​​battery cells; an encapsulation film, the encapsulation film is used to cover the surface of the battery string; a cover plate, the cover plate is used to cover the surface of the encapsulation film away from the battery string.

[0012] In some embodiments, it also includes: a second buffer adhesive film, the second buffer adhesive film is located on the end surfaces of the segmented battery cells on both sides of the battery string; a second welding strip, the second welding strip is electrically connected to the segmented battery cells on both sides of the battery string, and the second welding strip covers the surface of the second buffer adhesive film; a bus bar, the bus bar is electrically connected to the second welding strip, so as to be electrically connected to the plurality of battery strings through the second welding strip.

[0013] In some embodiments, the second buffer film protrudes from the end of the split battery sheet.

[0014] In some embodiments, welding points are provided on the sliced ​​battery cells, and the welding strips are in contact with and connected to the welding points. In the arrangement direction of the sliced ​​battery cells in any of the battery strings, the width of the buffer film is smaller than the distance between the two nearest welding points of the adjacent sliced ​​battery cells.

[0015] In some embodiments, in the arrangement direction of the segmented battery cells in any of the battery strings, the width of the buffer film is 3 to 10 mm, and in the arrangement direction perpendicular to the segmented battery cells, the length of the buffer film is 6 to 13 mm.

[0016] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: a method for manufacturing a battery string, a method for manufacturing a photovoltaic module, and a photovoltaic module are proposed, wherein in the method for manufacturing a battery string, before connecting two segmented battery cells in series, a buffer film is first laid on the end surface of the segmented battery cell, so that in the subsequent process of connecting the battery cells in series, the overlapping parts of adjacent segmented battery cells are provided with a buffer film, thereby reducing the interaction force on the overlapping parts of the segmented battery cells and avoiding abnormalities in the overlapping parts of the segmented battery cells. Secondly, the laser welding method can reduce the heat conducted to the buffer film. The laser welding method can also reduce the requirements for the performance of the buffer film material, thereby reducing the cost of the buffer film. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figures 1 to 5 A schematic structural diagram corresponding to each step of a method for manufacturing a battery string provided in an embodiment of the present disclosure;

[0019] Figures 6 to 11 A schematic structural diagram corresponding to each step of a method for manufacturing a photovoltaic module provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] As can be seen from the background art, currently when forming a battery string, overlapping adjacent battery cells is arranged as a means to increase the power of the battery string per unit area.

[0021] In the related art, in order to alleviate the mutual force between the overlapping parts of adjacent battery cells, the purpose of alleviating the mutual force between adjacent battery cells is usually achieved after the battery string is formed through processes such as breaking the cells, plugging the film and heating. However, through the above-mentioned methods, for the sliced ​​battery cells, the sliced ​​battery cells will have a certain opening angle, which will cause the adhesive film to fall off, especially for the sliced ​​battery cells that divide the initial battery cells into at least 3 pieces. The more the number of slices, the smaller the size of the formed sliced ​​battery cells. The small-sized sliced ​​battery cells are more seriously affected by the breaking of the slices, especially easily causing the solder strips in the sliced ​​battery cells to detach from the sliced ​​battery cells, resulting in poor welding.

[0022] The disclosed embodiment provides a method for manufacturing a battery string, by laying a buffer film on the end surface of a split battery cell before connecting two split battery cells in series. Thus, in the subsequent process of connecting the battery cells in series, the overlapping parts of adjacent split battery cells are provided with the buffer film, thereby reducing the interaction force on the overlapping parts of the split battery cells and avoiding abnormalities in the overlapping parts of the split battery cells. Secondly, laser welding can reduce the heat conducted to the buffer film. Laser welding can also reduce the requirements for the performance of the buffer film material, thereby reducing the cost of the buffer film.

[0023] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0026] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0027] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0028] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like 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 or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0029] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, a film, a region or a substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0030] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, a film, a region, or a plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0031] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0032] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can be implemented.

[0033] refer to Figures 1 to 5 , Figures 1 to 5 A schematic structural diagram corresponding to each step of a method for manufacturing a battery string provided in one embodiment of the present disclosure.

[0034] refer to Figure 1 , Figure 1 Schematic diagram of the structure of an initial battery cell; in some embodiments, a method for manufacturing a battery string may include: providing an initial battery cell 100.

[0035] The initial cell 100 includes, but is not limited to, one or any combination of PERC cells (Passivated Emitter Rear Cell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology), solar thin-film cells, and stacked cells. The solar thin-film cells include, but are not limited to, perovskite solar thin-film cells, copper indium selenide solar thin-film cells, gallium arsenide solar thin-film cells, and cadmium sulfide solar thin-film cells. The stacked cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0036] Taking TOPCon cells as an example, the initial cell 100 may have formed a front emitter 120 , a front passivation layer 130 , a front electrode 140 , a back oxide layer 150 , a back doped conductive layer 160 , a back passivation layer 170 and a back electrode 180 on the surface of a substrate 110 .

[0037] refer to Figure 2 , Figure 2For Figure 1 The structural schematic diagram of the sliced ​​battery cell is formed on the basis of the above, and the method for manufacturing the battery string may further include: slicing the initial battery cell 100 to form at least three sliced ​​battery cells 101.

[0038] It is understandable that, for the split cell 101 , the split cell 101 can also have a substrate 110 , a front emitter 120 , a front passivation layer 130 , a front electrode 140 , a back oxide layer 150 , a back doped conductive layer 160 , a back passivation layer 170 and a back electrode 180 .

[0039] In some embodiments, the cell slices 101 include edge cells having a cutting surface 111 , and before connecting adjacent cell slices 101 in series, the further step includes: adjusting the orientation of the cutting surface 111 of the edge cells so that the cutting surfaces 111 of the edge cells are oriented in the same direction.

[0040] It can be understood that in the process of slicing the initial battery cell, at least one cutting surface 111 will be formed on the formed sliced ​​battery cell 101. Taking the example of dividing the initial battery cell into three sliced ​​battery cells 101, two of the sliced ​​battery cells 101 have one cutting surface 111, and the one with one cutting surface 111 is the edge battery cell, and the remaining sliced ​​battery cell 101 has two cutting surfaces 111.

[0041] After forming the sliced ​​battery cells 101, the orientation of the cut surfaces 111 of the sliced ​​battery cells 101 is adjusted so that the cut surfaces 111 of the edge battery cells are oriented in the same direction. Taking the formation of three sliced ​​battery cells 101 as an example, the cut surfaces 111 of two sliced ​​battery cells 101 with only one cut surface 111 need to be adjusted to face the same side, and the remaining sliced ​​battery cell 101 with two cut surfaces 111 can be adjusted to face the same side as any one of the cut surfaces 111 of the sliced ​​battery cell 101 and the above two sliced ​​battery cells 101 with only one cut surface 111. By adjusting the sliced ​​battery cells 101 after forming them, it is convenient to connect the sliced ​​battery cells 101 in series later.

[0042] refer to Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of a structure for laying a buffer film on a split battery sheet according to an embodiment of the present disclosure. Figure 4This is another structural schematic diagram of laying a buffer film on the sliced ​​battery cells according to an embodiment of the present disclosure. The method for making a battery string may also include: laying a buffer film 102 on the end surface of the sliced ​​battery cell 101 close to the adjacent sliced ​​battery cell 101; performing a heat fixing treatment, the heat fixing treatment including: heating the buffer film 102 so that the buffer film 102 is adhered to the surface of the sliced ​​battery cell 101. By performing a heat fixing treatment after laying the buffer film 102, a preliminary fixation can be made between the buffer film 102 and the sliced ​​battery cell 101, thereby avoiding the buffer film 102 from falling off during the subsequent series connection of the sliced ​​battery cells 101, or avoiding the movement of the buffer film 102 during the series connection of the sliced ​​battery cells 101, resulting in abnormalities in the welding process, thereby improving the reliability of the battery string manufacturing method, thereby improving the reliability of the formed battery string.

[0043] for Figure 3 , Figure 3 The schematic diagram of the structure of laying a buffer film on a split battery sheet provided in the embodiment is that a buffer film is laid on both opposite sides of the split battery sheet. Figure 4 The structural schematic diagram of laying a buffer film on a sliced ​​battery sheet provided in the embodiment shows that a buffer film is laid on one side of the sliced ​​battery sheet.

[0044] As for the buffer film 102, the buffer film 102 can be pre-cut according to the required size, so as to avoid the need to cut the buffer film 102 later, reduce the production process of the battery string, reduce the production cost of the battery string, and prepare all materials in advance to facilitate the laying process.

[0045] In some embodiments, the method of laying the buffer film 102 may include: providing an initial buffer film after adjusting the orientation of the cutting surface 111 of the edge battery cell; cutting the initial buffer film (not shown in the figure) to form the buffer film 102, and moving the buffer film 102 to the end surface of the sliced ​​battery cell 101. In other words, after adjusting the orientation of the sliced ​​battery cell 101, the initial buffer film is cut, so that the size of the required buffer film 102 can be adjusted in real time according to the size of the sliced ​​battery cell 101. Compared with the solution of cutting in advance, the size of the required buffer film 102 can be more accurately controlled to facilitate the cooperation between the buffer film 102 and the sliced ​​battery cell 101, so as to more accurately adapt the buffer film 102 and the sliced ​​battery cell 101.

[0046] In some embodiments, before cutting the initial buffer film, the sliced ​​battery cell 101 is scanned to obtain the size of the sliced ​​battery cell 101, and the size of the sliced ​​battery cell 101 is fed back to the machine for cutting the initial buffer film, thereby controlling the machine for cutting the initial buffer film to cut the buffer film 102 of the required size. In this way, when the sliced ​​battery cell 101 has size deviations, the buffer film 102 of the required size can still be cut well.

[0047] In some embodiments, the process of laying the buffer film 102 may be to transport the buffer film 102 to the top or bottom of the battery cell, and then fix the buffer film 102 on the surface of the battery cell by vacuum adsorption.

[0048] In some embodiments, before the initial battery cell is cut into slices, the buffer adhesive film 102 may be fixed on the initial battery cell first, and then the initial battery cell is cut into slices.

[0049] For the heat fixation treatment, the process parameters of the heat fixation treatment include: a heating temperature of 60 to 70°C, such as 61°C, 63°C, 65°C, 66°C, 68°C or 69°C, etc., and a heating time of 0.5 to 1.5s, such as 0.7s, 0.9s, 1s, 1.2s or 1.4s, etc. It can be understood that for the buffer film 102, the higher the heating temperature, the higher the tightness of the connection between the buffer film 102 and the split battery cell 101. However, the higher the heating temperature, the more likely it is to damage the buffer film 102. The lower the heating temperature, the lower the tightness of the connection between the buffer and the split battery cell 101, which may cause the buffer film 102 to fall off in the subsequent manufacturing process of the battery string. Therefore, the heating temperature is set to 60 to 70°C, while taking into account the heating effect, it also avoids affecting the buffer film 102.

[0050] Similarly, for the heating time, the longer the heating time, the tighter the connection between the buffer film 102 and the sliced ​​battery cell 101 is. However, the longer the heating time, the more likely it is that the buffer film 102 will be damaged. The shorter the heating time, the lower the tightness of the connection between the buffer and the sliced ​​battery cell 101, which may cause the buffer film 102 to fall off in the subsequent manufacturing process of the battery string. Therefore, the heating time is set to 0.5-1.5s. While taking the heating effect into consideration, it also avoids affecting the buffer film 102 and controls the process duration of the heat fixing treatment, thereby controlling the manufacturing cost of the battery string.

[0051] In some embodiments, the material of the buffer film 102 can be a pre-cross-linked film such as EVA (Ethylene Vinyl Acetate Copolymer), POE (Polyolefin Elastomer), EPE (EVA-POE-EVA co-extruded material), etc. By controlling the buffer film 102 to be a pre-cross-linked film, the high temperature resistance of the buffer film 102 can be improved, thereby further avoiding being affected by the entire process, thereby further improving the reliability of the formed battery string.

[0052] refer to Figure 3 In some embodiments, the slice battery cell 101 includes a relative front side and a relative back side, and the buffer film 102 is located at opposite ends of the slice battery cell 101, wherein the buffer film 102 at one end is located at the front side of the slice battery cell 101, and the buffer film 102 at the other end is located at the back side of the slice battery cell 101. It can be understood that, for the overlapping portion of two adjacent slice battery cells 101, one of the slice battery cells 101 is located on the top surface of the other slice battery cell 101. Therefore, for the two adjacent slice battery cells 101, one of the slice battery cells 101 is subjected to force on the front side, and the other slice battery cell 101 is subjected to force on the back side. Therefore, setting the buffer films on both sides of the slice battery cell 101 on the front side and the back side respectively can better protect the slice battery cells.

[0053] refer to Figure 4 In some embodiments, the buffer film 102 may be located only on one side of the split battery cell 101 and on the front side of the split battery cell. It can be understood that, compared with the solution of locating the buffer film 102 at the opposite ends of the split battery cell 101, the solution of only arranging the buffer film 102 on one side of the split battery cell 101 and on the front side of the split battery cell has simpler process steps, and there is no need to consider how to fix the buffer film 102 on the back side of the split battery cell 101, which can reduce the process difficulty of the battery string manufacturing method.

[0054] refer to Figure 5 , Figure 5 For Figure 4In some embodiments, the method for making a battery string may further include: providing a welding strip 103, the welding strip 103 is electrically connected to at least two segmented battery cells 101 to connect adjacent segmented battery cells 101 in series, wherein adjacent segmented battery cells 101 partially overlap, and the welding strip 103 covers the buffer film 102 on the surface of the segmented battery cells 101; performing laser welding, the laser welding includes: controlling the laser to irradiate the surface of the welding strip 103 to weld the welding strip 103 to the surface of the segmented battery cells 101. It can be understood that, for laser welding, laser welding forms an instantaneous high temperature at the contact interface between the soldering ribbon 103 and the segmented battery cell 101 by laser bombardment, so as to fix the soldering ribbon 103 on the segmented battery cell 101. Moreover, the laser welding method does not cause too much impact on the buffer film 102 due to the instantaneous high temperature. Therefore, the laser welding method can reduce the impact on the buffer film 102, thereby reducing the requirements for the material of the buffer film 102, and reducing the difficulty and cost of the entire manufacturing method.

[0055] In some embodiments, the welding strip 103 may include two main parts and a connecting part connecting the two main parts, wherein the thickness of the main part is greater than the thickness of the connecting part, and the connecting part is directly opposite to the overlapping part of the sliced ​​battery cell 101. In other words, the welding strip 103 has a structure that is thick at both ends and thin in the middle, so as to adapt to the connection condition of the sliced ​​battery cell 101 and avoid excessive warping of the overlapping part of the sliced ​​battery cell 101, thereby reducing the possibility of abnormalities in the formed battery string.

[0056] Understandably, Figure 5 Only the buffer film 102 is shown to be located on one side of the split solar cell 101. The corresponding solder strip morphology includes two main parts and a connecting part. Figure 5 and Figure 3 The structure shown is adjusted accordingly.

[0057] The disclosed embodiment provides a method for manufacturing a battery string, by laying a buffer film 102 on the end surface of a slice battery cell 101 before connecting two slice battery cells 101 in series. In this way, in the subsequent process of connecting the battery cells in series, the overlapping parts of adjacent slice battery cells 101 are provided with the buffer film 102, thereby reducing the interaction force on the overlapping parts of the slice battery cells 101 and avoiding abnormalities in the overlapping parts of the slice battery cells 101. Secondly, the laser welding method can reduce the heat conducted to the buffer film 102. The laser welding method can also reduce the requirements for the material properties of the buffer film 102, thereby reducing the cost of the buffer film 102.

[0058] Another embodiment of the present disclosure further provides a method for manufacturing a photovoltaic module, which may include the above-mentioned method for manufacturing a battery string. The method for manufacturing a photovoltaic module provided by another embodiment of the present disclosure will be described below in conjunction with the accompanying drawings. It should be noted that the same or corresponding parts of the aforementioned embodiments can refer to the corresponding description of the aforementioned embodiments and will not be repeated below.

[0059] refer to Figures 6 to 11 , Figures 6 to 11 A schematic diagram of the structures corresponding to each step of the method for manufacturing a photovoltaic module provided in an embodiment of the present disclosure.

[0060] refer to Figure 6 and Figure 7 , Figure 6 A schematic diagram of the structure of a battery string provided in one embodiment of the present disclosure is shown in FIG. Figure 7 A schematic diagram of another battery string structure provided by an embodiment of the present disclosure. In some embodiments, a method for manufacturing a photovoltaic module may include: providing a plurality of battery strings 40, each battery string 40 including a plurality of sliced ​​battery cells 101, and a first welding strip 103 connecting the plurality of sliced ​​battery cells 101 in series.

[0061] The first welding strip 103 here is the same as the welding strip 103 in the above embodiment. The manufacturing method of the battery string 40 can be formed by the manufacturing method in all or part of the above embodiments, which will not be described in detail below.

[0062] refer to Figure 8 , Figure 8 for Figure 7 The enlarged schematic diagram of the structure in the dotted circle is Figure 7 The second buffer film is formed on the basis of. The method for manufacturing a photovoltaic module may also include: laying a second buffer film 104 on the surface of the sliced ​​battery cells 101 on both sides of the battery string 40, and the second buffer film 104 is located at the end of the sliced ​​battery cells 101. For the battery string 40, the battery string 40 needs to be electrically connected to the bus bar 106 through the second welding strip 105, and for the photovoltaic module, the edge of the photovoltaic module is actually the edge of the battery string 40, and the edge of the photovoltaic module may be deformed, causing the photovoltaic module to be abnormal. Therefore, laying the second buffer film 104 on the surface of the sliced ​​battery cells 101 on both sides of the battery string 40, on the one hand, when the battery string 40 and the battery string 40 are connected in series or in parallel, the force on the top of the sliced ​​battery cell 101 of the battery string 40 close to the adjacent battery string 40 is reduced, thereby improving the reliability of the formed photovoltaic module, and on the other hand, it can reduce the force on the sliced ​​battery cell 101 at the edge of the photovoltaic module, thereby reducing the possibility of damage to the edge of the photovoltaic module.

[0063] It is understandable that after the second buffer film 104 is laid on the surface of the sliced ​​battery cell 101, a heat fixing treatment can also be performed. The second buffer film 104 can be fixed on the sliced ​​battery cell 101 on both sides of the battery string 40 through the heat fixing treatment, thereby avoiding the second buffer film 104 from falling off in the subsequent manufacturing process, and the reliability of the photovoltaic module manufacturing process can be improved.

[0064] It should be noted that the heat fixing treatment applied to the second buffer adhesive film 104 may be the same as the heat fixing treatment applied in the above embodiment. For the corresponding description, reference may be made to the description of the heat fixing treatment in the above embodiment, which will not be described in detail below.

[0065] In some embodiments, during the process of laying the second buffer film 104, the second buffer film 104 can be formed on both the front and back sides of the same side of the segmented battery cell 101. For the battery string 40, some of the battery strings 40 are electrically connected to the second welding ribbon 105 on the front side, and some of the battery strings 40 are electrically connected to the second welding ribbon 105 on the back side. By forming the second buffer film 104 on both the front and back sides of the segmented battery cell 101 at the edge of the battery string 40, the process of manufacturing the photovoltaic module can be simplified, and there is no need to distinguish which battery strings are electrically connected to the second welding ribbon 105 on the front side and which battery strings are electrically connected to the second welding ribbon 105 on the back side.

[0066] refer to Fig. 9 and Fig.10 , Fig. 9 For Figure 8 The second welding strip is formed on the basis of Fig.10 For Fig. 9 The busbars are formed on the basis of Fig.10 The structure of the second buffer film is not shown in the figure.

[0067] In some embodiments, the method for manufacturing a photovoltaic module may further include: providing a second welding ribbon 105, the second welding ribbon 105 is electrically connected to the split battery cells 101 on both sides of the battery string 40, and the second welding ribbon 105 covers the surface of the second buffer film 104; providing a bus bar 106, the bus bar 106 is electrically connected to the second welding ribbon 105, so as to be electrically connected to multiple battery strings 40 through the second welding ribbon 105. The second welding ribbon 105 is used to lead out the connection port of the circuit of the battery string 40, so as to facilitate the connection between the battery string 40 and the bus bar 106, and the bus bar 106 is used to cooperate with the second welding ribbon 105 to connect different battery strings 40 in series or in parallel, so as to facilitate the control of the output voltage and output current of the photovoltaic module.

[0068] The second welding strip 105 can be electrically connected to the split battery cell 101 by laser welding, which can reduce the impact on the second buffer film 104, thereby reducing the requirements for the material of the second buffer film 104 and reducing the difficulty and cost of the entire manufacturing method.

[0069] It should be noted that the laser welding process for electrically connecting the second welding ribbon 105 and the split battery cell 101 can be the same as the laser welding process used in the above embodiment. The corresponding description can refer to the description of laser welding in the above embodiment, which will not be repeated below.

[0070] refer to Fig.11 , Fig.11 A cross-sectional view of a photovoltaic module provided in an embodiment of the present disclosure. In some embodiments, the method for manufacturing a photovoltaic module may further include: forming a packaging film 41, the packaging film 41 is used to cover the surface of the battery string 40; forming a cover plate 42, the cover plate 42 is used to cover the surface of the packaging film 41 away from the battery string 40.

[0071] In some embodiments, the packaging film 41 includes a first packaging film and a second packaging film, the first packaging film covers one of the front side or the back side of the battery string 40, and the second packaging film covers the other of the front side or the back side of the battery string 40. Specifically, at least one of the first packaging film or the second packaging film can be an organic packaging film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film or a polyethylene terephthalate (PET) film.

[0072] In some cases, there is a boundary line between the first encapsulation film and the second encapsulation film before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation film and the second encapsulation film, that is, the first encapsulation film and the second encapsulation film have formed an integral encapsulation film 41.

[0073] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the packaging film 41 may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first packaging film, and the second cover plate is opposite to the second packaging film.

[0074] The disclosed embodiment adopts a method for manufacturing a photovoltaic module, wherein a second buffer film 104 is laid on the surfaces of the sliced ​​battery cells 101 on both sides of a battery string 40, thereby reducing the stress on the sliced ​​battery cells 101 at the edges during the process of connecting the battery strings 40 in series or in parallel, thereby improving the reliability of the formed photovoltaic module. Furthermore, by laying the second buffer film 104 on the surfaces of the sliced ​​battery cells 101 on both sides of the battery string 40, after the photovoltaic module is formed, the sliced ​​battery cells 101 at the edge of the photovoltaic module are all laid with the second buffer film 104, thereby reducing the probability of damage to the edge of the photovoltaic module.

[0075] Another embodiment of the present disclosure further provides a photovoltaic module, which may include a battery string formed by the battery string manufacturing method in some or all of the above embodiments, or formed by the photovoltaic module manufacturing method in some or all of the above embodiments. The photovoltaic module provided by another embodiment of the present disclosure will be described below in conjunction with the accompanying drawings. It should be noted that the same or corresponding parts of the above embodiments can refer to the corresponding description of the above embodiments and will not be repeated below.

[0076] Combined with reference Figure 5 , Figure 7 , Fig. 9 , Fig.10 and Fig.11 In some embodiments, a photovoltaic module may include: a battery string 40, the battery string 40 includes: a plurality of sliced ​​battery cells 101; a buffer film 102, the buffer film 102 is located on the end surface of the sliced ​​battery cell 101 close to the adjacent sliced ​​battery cell 101; a welding strip 103, the welding strip 103 is electrically connected to at least two sliced ​​battery cells 101 to connect adjacent sliced ​​battery cells 101 in series, the adjacent sliced ​​battery cells 101 partially overlap, and the welding strip 103 covers the buffer film 102 on the surface of the sliced ​​battery cell 101.

[0077] The photovoltaic module may include: a packaging film 41 , and the packaging film 41 is used to cover the surface of the battery string 40 .

[0078] The photovoltaic module may include a cover plate 42 , which is used to cover the surface of the packaging film 41 away from the battery string 40 .

[0079] For photovoltaic modules, a buffer film 102 is provided at the overlapping portion of two adjacent segmented battery cells 101 of the battery string 40 to reduce the interaction force between the two adjacent segmented battery cells 101, thereby avoiding damage between the two adjacent segmented battery cells 101 due to the interaction force, thereby improving the reliability of the photovoltaic module.

[0080] In some embodiments, the sliced ​​battery cells 101 are formed by cutting the same initial battery cell, and the sliced ​​battery cells 101 can be at least 3 sliced ​​battery cells 101 formed by cutting the same initial battery cell at least twice. For the sliced ​​battery cells 101, the more the same initial battery cell is cut, the more likely the sliced ​​battery cells 101 are to be damaged due to the interaction force. Therefore, setting a buffer film 102 on the overlapping parts of the sliced ​​battery cells 101 can effectively improve this phenomenon.

[0081] In some embodiments, the width of the split battery cell 101 can be 40 to 86 mm, for example, 61 mm, 65 mm, 70 mm, 76 mm, 77 mm or 79 mm, etc., and the length can be 180 to 260 mm, for example, 182.3 mm, 191 mm, 200 mm, 210 mm, 223 mm, 230 mm or 240 mm, etc.

[0082] In some embodiments, welding points (not shown in the figure) are provided on the sliced ​​solar cells 101, and the welding strips 103 are in contact with the welding points. In the arrangement direction of the sliced ​​solar cells 101 in any battery string 40, the width of the buffer film 102 is less than the distance between the two nearest welding points of adjacent sliced ​​solar cells 101. Providing welding points on the sliced ​​solar cells 101 can facilitate the connection between the sliced ​​solar cells 101 and the welding strips 103. Providing the width of the buffer film 102 is less than the distance between the two nearest welding points of two adjacent sliced ​​solar cells 101 can avoid the buffer film 102 covering the welding points of the sliced ​​solar cells 101, and can avoid the buffer film 102 affecting the connection between the welding strip 103 and the welding points, thereby improving the reliability of the photovoltaic module.

[0083] In some embodiments, the distance between the two nearest welding points of adjacent segmented solar cells 101 can be 6 to 18 mm, for example, 7 mm, 8 mm, 12 mm, 16 mm or 17 mm, etc. It can be understood that the smaller the distance between the two nearest welding points of adjacent segmented solar cells 101 is, the smaller the size reserved for installing the buffer film 102 is, which will increase the difficulty of installing the buffer film 102, because the smaller the reserved space is, the greater the difficulty of positioning is, and setting the distance between the two nearest welding points of adjacent segmented solar cells 101 too large will reduce the reliability of the connection between the welding ribbon 103 and the segmented solar cell 101. Therefore, the distance between the two nearest welding points of adjacent segmented solar cells 101 is set to 6 to 18 mm. While considering the reliability of the connection between the welding ribbon 103 and the segmented solar cell 101, the installation space of the buffer film 102 is also taken into account.

[0084] In some embodiments, the buffer film 102 protrudes from the end of the sliced ​​cell 101. It can be understood that the sliced ​​cell 101 has some edges. Compared with the surface of the sliced ​​cell 101, the edges are more easily deformed and damaged when subjected to force. The buffer film 102 is arranged to protrude from the end of the sliced ​​cell 101. The buffer film 102 can also protect the edges of the sliced ​​cell 101, thereby further improving the reliability of the photovoltaic module.

[0085] In the arrangement direction of the segmented battery cells 101 in any battery string 40, the width of the buffer film 102 is 3 to 10 mm, for example, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or 9 mm, etc., and in the arrangement direction perpendicular to the segmented battery cells 101, the length of the buffer film 102 is 6 to 13 mm, for example, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm or 12 mm, etc. As for the width and length of the buffer film 102, the larger the width and length of the buffer film 102, the larger the size of the sliced ​​battery cell 101 that can be protected by the buffer film 102. Similarly, the larger the width and length of the buffer film 102, the higher the cost of the buffer film 102, and it may also affect the reliability of the connection between the sliced ​​battery cell 101 and the welding strip 103. Therefore, setting the width of the buffer film 102 to 3 to 10 mm and the length of the buffer film 102 to 6 to 13 mm can take into account the protective performance of the buffer film 102 while avoiding the buffer film 102 affecting the reliability of the battery string 40.

[0086] In some embodiments, the length of the buffer film 102 can be smaller than the spacing between two adjacent solder strips in the sliced ​​cell 101, thereby preventing the buffer film 102 from affecting the connection between the solder strip and the sliced ​​cell 101, thereby preventing the buffer film 102 from affecting the reliability of the photovoltaic module.

[0087] The length of the buffer film 102 can also be equal to the length of the sliced ​​battery cell 101. For the buffer film 102, the longer the length of the buffer film 102 is, the stronger the ability to protect the sliced ​​battery cell 101 is. The length of the buffer film 102 can also be equal to the length of the sliced ​​battery cell 101, and it can also protect the edges and corners of the sliced ​​battery cell 101, thereby reducing the probability of the sliced ​​battery cell 101 being damaged.

[0088] In some embodiments, the material of the buffer film 102 may include: EVA material with a cross-linking degree of 5% to 70%, POE material with a cross-linking degree of 5% to 70%, or EPE material with a cross-linking degree of 5% to 70%.

[0089] It should be noted that the higher the degree of cross-linking, the higher the cohesive strength of the buffer film 102 and the viscosity between the buffer film 102 and the split battery cell 101. However, the higher the degree of cross-linking, the harder the material of the buffer film 102 will be, which will reduce the buffering capacity of the buffer film 102. Therefore, setting the degree of cross-linking of the material to 5% to 70% can improve the reliability of the connection between the buffer film 102 and the split battery cell 101 while avoiding affecting the buffering capacity of the buffer material.

[0090] Moreover, as for the degree of cross-linking, the higher the degree of cross-linking, the stronger the material's ability to resist thermal aging. When high-temperature welding is used to connect the soldering ribbon 103 and the battery cell, the degree of cross-linking of the buffer film 102 material can be appropriately increased to avoid thermal aging of the buffer film 102 during the manufacturing process and to avoid excessive impact on the life of the buffer film 102.

[0091] In some embodiments, the photovoltaic module may also include: a second buffer film 104, the second buffer film 104 is located on the end surfaces of the segmented battery cells 101 on both sides of the battery string 40; a second welding strip 105, the second welding strip 105 is electrically connected to the segmented battery cells 101 on both sides of the battery string 40, and the second welding strip 105 covers the surface of the second buffer film 104; a bus bar 106, the bus bar 106 is electrically connected to the second welding strip 105, so as to be electrically connected to multiple battery strings 40 through the second welding strip 105. The second welding strip 105 is used to lead out the connection port of the circuit of the battery string 40, so as to facilitate the connection between the battery string 40 and the bus bar 106. The bus bar 106 is used to cooperate with the second welding strip 105 to connect different battery strings 40 in series or in parallel, so as to facilitate the control of the output voltage and output current of the photovoltaic module. The second buffer film 104 can reduce the interaction force between the second welding strip 105 and the battery string 40, and can reduce the impact on the sliced ​​battery cell 101 in the photovoltaic module manufacturing process. Moreover, the second buffer film 104 can also reduce the force on the sliced ​​battery cell 101 at the edge of the photovoltaic module, thereby reducing the possibility of damage to the edge of the photovoltaic module.

[0092] In some embodiments, the second buffer film 104 protrudes from the end of the sliced ​​battery cell 101. First, the second buffer film 104 is the end surface of the sliced ​​battery cell 101 located on both sides of the battery string 40. For the sliced ​​battery cells 101 on both sides of the battery string 40, they are either sliced ​​battery cells 101 connected to the adjacent battery string 40, or sliced ​​battery cells 101 as the edge of the photovoltaic module. The sliced ​​battery cells 101 at these two positions are also more prone to abnormalities such as deformation or breakage. Therefore, the second buffer film 104 is also provided to protrude from the end of the sliced ​​battery cell 101, which can further protect the sliced ​​battery cells 101 on both sides of the battery string 40, thereby improving the reliability of the photovoltaic module.

[0093] As for the second buffer film 104 , the size of the second buffer film 104 can be consistent with the size of the buffer film 102 , thereby reducing the difficulty of the photovoltaic module manufacturing process.

[0094] The size of the second buffer film 104 may also be larger than that of the buffer film 102. The second buffer film 104 is disposed between the battery strings. To ensure that the second buffer film 104 can provide sufficient buffering capacity, the size of the second buffer film 104 may be increased. Moreover, increasing the size of the second buffer film 104 may also separate the battery string from the edge of the photovoltaic module, thereby further protecting the battery string 40.

[0095] The width of the second buffer film 104 can be 4 to 15 mm, and the length of the second buffer film 104 can be 6 to 20 nm. By setting the width of the second buffer film 104 to 4 to 15 mm and the length to 6 to 20 nm, the protection performance of the second buffer film 104 can be taken into account while preventing the second buffer film 104 from affecting the reliability of the photovoltaic module.

[0096] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, so the protection scope of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A method for manufacturing a battery string, characterized in that: include: Providing initial battery cells; Slicing the initial battery cell to form at least three sliced ​​battery cells; Laying a buffer film on the end surface of the split battery sheet close to the adjacent split battery sheet; Performing a heat fixation process, the heat fixation process comprising: heating the buffer adhesive film so that the buffer adhesive film adheres to the surface of the split battery cell; Providing a welding strip, wherein the welding strip is electrically connected to at least two of the sliced ​​solar cells to connect adjacent sliced ​​solar cells in series, wherein the adjacent sliced ​​solar cells partially overlap, and the welding strip covers the buffer film on the surface of the sliced ​​solar cells; Laser welding is performed, and the laser welding includes: controlling the laser to irradiate the surface of the welding strip to weld the welding strip to the surface of the sliced ​​battery cell.

2. The method according to claim 1, characterized in that: The process parameters of the heat fixation treatment include: a heating temperature of 60 to 70° C. and a heating time of 0.5 to 1.5 s.

3. The method according to claim 1, characterized in that: The cell slices include an edge cell slice having a cutting surface, and before connecting adjacent cell slices in series, the further step includes: adjusting the orientation of the cutting surfaces of the edge cell slices so that the cutting surfaces of the edge cell slices are oriented in the same direction.

4. The method according to claim 3, characterized in that: The method for laying the buffer film comprises: Providing an initial buffer adhesive film after adjusting the orientation of the cut surface of the edge battery sheet; The initial buffer adhesive film is cut to form the buffer adhesive film, and the buffer adhesive film is moved to the end surface of the sliced ​​battery sheet.

5. A method for manufacturing a photovoltaic module, characterized in that: include: Providing a plurality of battery strings, each battery string comprising a plurality of sliced ​​battery sheets, and a first welding strip connecting the plurality of sliced ​​battery sheets in series; Laying a second buffer adhesive film on the surfaces of the split battery sheets on both sides of the battery string, wherein the second buffer adhesive film is located at the ends of the split battery sheets; Providing a second welding ribbon, wherein the second welding ribbon is electrically connected to the split battery sheets on both sides of the battery string, and the second welding ribbon covers the surface of the second buffer film; Providing a bus bar, wherein the bus bar is electrically connected to the second welding ribbon so as to be electrically connected to the plurality of battery strings through the second welding ribbon; forming a packaging film, wherein the packaging film is used to cover the surface of the battery string; A cover plate is formed, wherein the cover plate is used to cover the surface of the packaging film away from the battery string.

6. A photovoltaic module, characterized in that: include: A battery string, the battery string comprising: a plurality of sliced ​​battery sheets; a buffer film, the buffer film being located on the end surface of the sliced ​​battery sheet close to the adjacent sliced ​​battery sheet; a welding strip, the welding strip being electrically connected to at least two of the sliced ​​battery sheets to connect the adjacent sliced ​​battery sheets in series, the adjacent sliced ​​battery sheets partially overlapping, the welding strip covering the buffer film on the surface of the sliced ​​battery sheet; A packaging film, the packaging film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film away from the battery string.

7. The photovoltaic module according to claim 6, characterized in that: Also includes: A second buffer adhesive film, the second buffer adhesive film is located on end surfaces of the split battery sheets on both sides of the battery string; A second welding ribbon, wherein the second welding ribbon is electrically connected to the split battery sheets on both sides of the battery string, and the second welding ribbon covers a surface of the second buffer film; A bus bar is electrically connected to the second welding ribbon so as to be electrically connected to the plurality of battery strings through the second welding ribbon.

8. The photovoltaic module according to claim 7, characterized in that: The second buffer film protrudes from the end of the split battery sheet.

9. The photovoltaic module according to claim 6, characterized in that: The segmented battery cells are provided with welding spots, the welding strips are in contact with the welding spots, and in the arrangement direction of the segmented battery cells in any of the battery strings, the width of the buffer film is smaller than the distance between the two nearest welding spots of the adjacent segmented battery cells.

10. The photovoltaic module according to claim 6 or 9, characterized in that: In the arrangement direction of the segmented battery cells in any of the battery strings, the width of the buffer film is 3 to 10 mm, and in the arrangement direction perpendicular to the segmented battery cells, the length of the buffer film is 6 to 13 mm.

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