Photovoltaic module preparation method and photovoltaic module

Abstract

The invention provides a photovoltaic module preparation method and a photovoltaic module, and the method comprises the steps: providing a first battery string and a second battery string, and enabling a first end battery piece of the first battery string to be provided with a first end part welding strip; and the first end battery piece of the second battery string is provided with a second end part welding strip. A bus bar assembly is provided, the bus bar assembly comprises an insulating film strip, bus bars located on the two sides of the insulating film strip respectively and a plurality of metal sheets, and the metal sheets are welded to the bus bars at the first temperature through the hollowed-out parts on the insulating film strip; and placing the first battery string and the second battery string along the length direction of the battery strings, and overlapping the extending part of the second end welding strip on the first end battery piece of the first battery string. And arranging the bus bar assembly on the first end battery piece of the first battery string. Laminating at a second temperature, so that each metal sheet of the bus bar assembly is welded to the corresponding first end welding strip and second end welding strip; the second temperature is lower than the first temperature. According to the invention, the risk of cell cracking caused by a pressing welding mode can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic product production, in particular to a photovoltaic module preparation method and a photovoltaic module. BACKGROUND

[0002] In a conventional photovoltaic module, after the cell string is arranged, the bus bar is welded on the overlength solder strip at the end of the cell string. The overlength solder strip refers to the part of the solder strip on the end cell of the cell string that extends out of the end cell. During welding, the bus bar is carried on the loading platform, the overlength solder strip is placed above the bus bar, the pressing head presses the overlength solder strip against the bus bar, and the loading platform or the pressing head heats the bus bar and the overlength solder strip to realize the welding connection of the two.

[0003] However, since the bus bar is located outside the cell, the area where the bus bar is located cannot generate electricity, and the power generation efficiency per unit area of the photovoltaic module is low.

[0004] At present, a new type of photovoltaic module has appeared, which places the bus bar inside the back of the cell and welds it with the predetermined solder strip on the back of the cell, thereby saving the space occupied by the bus bar and improving the power generation efficiency per unit area of the photovoltaic module. However, since the bus bar and the solder strip are both located inside the back of the cell, directly using the above pressing and welding method to weld the bus bar is easy to cause the cell to crack. SUMMARY

[0005] In view of the above technical problems, the present application provides a photovoltaic module preparation method, and the detailed technical solutions are as follows:

[0006] A photovoltaic module preparation method comprises the following steps:

[0007] A first cell string and a second cell string are provided, and the first cell string and the second cell string are both formed by connecting cell pieces by solder strips. The cell piece is a back contact cell piece. The back surface of the first end cell piece of the first cell string has a first end portion solder strip. The back surface of the first end cell piece of the second cell string has a second end portion solder strip, and the second end portion solder strip extends out of the first end cell piece of the second cell string.

[0008] A bus bar assembly is provided, which comprises an insulating film strip, a bus bar located on the first side of the insulating film strip, and a plurality of metal pieces located on the second side of the insulating film strip. The metal pieces are arranged at intervals along the length direction of the insulating film strip. The insulating film strip is provided with a hollow part corresponding to each metal piece. The metal piece located in each hollow part is welded and connected with the bus bar at a first temperature.

[0009] The first cell string and the second cell string are placed along the length direction of the cell string, and the extended part of the second end portion solder strip is placed on the back surface of the first end cell piece of the first cell string and corresponds to the first end portion solder strip one by one.

[0010] The busbar assembly is placed on the back of the first end cell of the first battery string, so that each metal piece of the busbar assembly is placed on top of each first end solder strip, and each metal piece is bonded to a pair of first end solder strips and a second end solder strip by adhesive.

[0011] The lamination is performed at a second temperature, so that each metal sheet of the busbar assembly is welded to the corresponding first end solder strip and second end solder strip;

[0012] The second temperature is lower than the first temperature.

[0013] The photovoltaic module manufacturing method of this application involves first individually welding the busbar, insulating film strip, and several metal sheets at a first temperature to prepare a busbar module. This facilitates reliable welding between the busbar and the metal sheets at higher temperatures. The insulating film strip ensures that after the busbar module is placed on the back of the first end cell of the first cell string, the busbar is insulated from another set of solder strips on the back of the first end cell, excluding the first end solder strip. By adhesively bonding the metal sheets in the busbar module to a pair of first end solder strips and a second end solder strip, the connection between the busbar module and the solder strips is achieved, avoiding the need for compression welding. This method mitigates the risk of cell cracking and achieves precise positioning between the metal sheet and the solder ribbon, ensuring accurate welding during lamination. By laminating at a second temperature lower than the first temperature, secondary welding at the welding points between the busbar and the metal sheet during lamination is avoided, while simultaneously enabling welding connections between the metal sheet and the corresponding solder ribbon. The metal sheet, acting as the connection medium between the busbar and the solder ribbon, provides a large contact area with the first and second end solder ribbons during adhesive bonding, resulting in a stronger bond. Furthermore, it improves the reliability of the welding connection between the busbar and the solder ribbon, ultimately ensuring the reliability of the module.

[0014] In some embodiments, the first end solder strip extends outward from the first end of the first battery cell of the first battery string. After the first battery string and the second battery string are placed along the length of the battery string, the first end solder strip overlaps the back of the first end of the second battery cell. Alternatively, the first end solder strip does not extend outward from the first end of the first battery cell of the first battery string.

[0015] The first end solder strip extends outward to the first end of the first battery cell of the first battery string. The first battery string and the second battery string are battery strings with the same structure. That is to say, only a single structure of battery string needs to be prepared according to a unified production process to obtain the final photovoltaic module, thereby reducing the complexity of battery string preparation and improving production efficiency.

[0016] In some embodiments, the metal sheet is copper foil.

[0017] Copper foil possesses excellent electrical conductivity and ductility. During the first-temperature soldering process, the copper foil forms a strong, low-resistance solder joint with the busbar, achieving stable and reliable welding. When adhesively bonding the first and second end solder strips, the copper foil's excellent ductility encapsulates the solder strip, increasing the contact area and strengthening the bond. During the second-temperature lamination process, the copper foil forms a reliable welded connection with both the first and second end solder strips, ultimately ensuring an unobstructed current conduction path from the solder strip to the copper foil and then to the busbar.

[0018] In some embodiments, both the first battery string and the second battery string are formed by connecting battery cells in series with solder strips, including: connecting the battery cells and solder strips in series by adhesive bonding to obtain the first battery string or the second battery string.

[0019] The solar cells and solder ribbons are connected in series by adhesive bonding, which avoids thermal damage to the solar cells caused by high-temperature welding. This series connection method is especially suitable for solar cells that are not resistant to high temperatures and solar cells without main grids.

[0020] In some embodiments, the battery cells and solder ribbons are connected in series by adhesive bonding, including:

[0021] Adhesive is applied to the solder ribbon laying path on the battery cell; the solder ribbon and the glued battery cell are laid and stacked according to a predetermined stringing rule, and the adhesive is cured so that the solder ribbon is bonded to the battery cell through the adhesive on the corresponding battery cell; or, the solder ribbon and battery cell are laid and stacked according to a predetermined stringing rule; adhesive is applied to the stacked solder ribbon, and the adhesive is cured so that the solder ribbon is bonded to the corresponding battery cell through the adhesive; or, the solder ribbon and battery cell are laid and stacked according to a predetermined stringing rule; an adhesive film is laid on the stacked solder ribbon, and the adhesive film is heated to bond the solder ribbon to the corresponding battery cell using the adhesive film.

[0022] Several easy-to-implement adhesive bonding series connection methods are provided, all of which can quickly bond the cells and solder ribbons into strings while ensuring the quality of the cell string connection.

[0023] In some embodiments, before placing the busbar assembly onto the back of the first end cell of the first cell string, the photovoltaic module manufacturing method further includes: applying adhesive to the metal sheet of the busbar assembly, or applying adhesive to the first end solder strip and the second end solder strip.

[0024] Two adhesive application methods are provided, both of which allow the paired first-end solder strips and second-end solder strips to be bonded to the corresponding metal sheets.

[0025] In some embodiments, the first temperature is above 200°C and the second temperature is below 160°C.

[0026] Setting the first temperature above 200°C ensures a reliable weld between the busbar and the metal sheet. Setting the second temperature below 160°C allows for a welded connection between the metal sheet and the corresponding solder strip, while also preventing secondary welding at the weld points between the busbar and the metal sheet.

[0027] In some embodiments, providing a busbar assembly includes: opening a plurality of through holes at intervals along the length of an insulating film strip to form a plurality of hollow portions; placing the busbar on a first side of the insulating film strip such that the busbar covers each through hole; providing metal sheets corresponding to the through hole positions on a second side of the insulating film strip; and welding each metal sheet to the busbar using a first temperature.

[0028] A convenient method for fabricating a busbar assembly is provided, which enables rapid fabrication of the busbar assembly and ensures that each metal sheet can be stably welded to the busbar through the corresponding through holes.

[0029] In some embodiments, the back of the second-end cells of the first battery string has a third end solder strip; the back of the second-end cells of the second battery string has a fourth end solder strip; the photovoltaic module manufacturing method further includes: placing a busbar assembly on the back of the second-end cells of at least two first battery strings, such that each metal piece of the busbar assembly is placed on top of each third end solder strip, and each metal piece is bonded to a corresponding third end solder strip by adhesive, and each first battery string is placed side by side along the width direction of the battery string; placing the busbar assembly on the back of the second-end cells of at least two second battery strings, such that each metal piece of the busbar assembly is placed on top of each fourth end solder strip, and each metal piece is bonded to a corresponding fourth end solder strip by adhesive, and each second battery string is placed side by side along the width direction of the battery string; heating with a second temperature, such that each metal piece of the busbar assembly is welded to the corresponding third end solder strip or fourth end solder strip.

[0030] Welding of the busbars at both ends of the photovoltaic module is achieved. Similarly, by adhesively bonding the metal sheet in the busbar assembly to the solder strip at the third or fourth end, the connection between the busbar assembly and the solder strip is realized. This avoids the risk of cell cracking caused by compression welding and ensures the positioning of the metal sheet and solder strip, guaranteeing precise welding between them during lamination. Furthermore, lamination at a second temperature lower than the first temperature avoids secondary welding at the weld points between the busbar and the metal sheet during lamination. It also enables welding connections between the metal sheet and the corresponding solder strip. The metal sheet, acting as the connection medium between the busbar and the solder strip, improves the reliability of the connection, ultimately ensuring the reliability of the module.

[0031] A second aspect of this application provides a photovoltaic module manufactured by any of the photovoltaic module manufacturing methods described above.

[0032] The photovoltaic module provided in this application uses a metal sheet as the connection medium between the busbar and the solder strip, which improves the connection reliability between the busbar and the solder strip and ultimately ensures the reliability of the photovoltaic module. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the first battery string;

[0034] Figure 2 This is a schematic diagram of the second battery string;

[0035] Figure 3 This is a schematic diagram showing the connection of a pair of first and second battery strings in a photovoltaic module according to one embodiment of this application.

[0036] Figure 4 for Figure 3 A magnified view of a portion of region A in the middle;

[0037] Figure 5 This is a schematic diagram of the connection between a pair of first battery strings and a second battery string in an optoelectronic assembly in another embodiment of this application, wherein only the first end battery cells of the first battery string and the second battery string that are close to each other are shown;

[0038] Figure 6 This is a schematic diagram of the structure of one side surface of the busbar assembly;

[0039] Figure 7 This is a schematic diagram of the structure of the other side surface of the busbar assembly;

[0040] Figure 8 This is a schematic diagram of the back of the photovoltaic module in the embodiments of this application;

[0041] Figure 9 This is a partially enlarged view of the back side of the photovoltaic module in the embodiments of this application;

[0042] Figure 10 This is a partial perspective magnified view of the front of the photovoltaic module in the embodiments of this application;

[0043] Figures 1 to 10 Includes:

[0044] First battery string 100:

[0045] First end weld strip 101, first intermediate weld strip 102, third end weld strip 103, third intermediate weld strip 104;

[0046] Second battery string 200:

[0047] Second end weld strip 201, second intermediate weld strip 202, fourth end weld strip 203, fourth intermediate weld strip 204;

[0048] Busbar assembly 300:

[0049] Insulating film strip 301, busbar 302, metal sheet 303, hollow part 304. Detailed Implementation

[0050] To make the above-mentioned objects, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0051] As described in the background section, the new photovoltaic modules that have emerged recently are prone to cell cracking because the busbars and solder strips are located on the inner side of the back of the solar cell when the busbars are directly welded using a pressure welding method.

[0052] To address this issue, this application provides a method for manufacturing photovoltaic modules that avoids the risk of cell cracking caused by compression welding.

[0053] Please refer to the reference. Figures 1 to 10 As shown, the method for manufacturing photovoltaic modules provided in this application includes:

[0054] S1. A first battery string 100 and a second battery string 200 are provided. Both the first battery string 100 and the second battery string 200 are formed by connecting battery cells in series via solder strips. The battery cells are back-contact battery cells. The first end battery cell of the first battery string 100 (e.g., Figure 1 The battery cell shown at the right end has a first end solder strip 101 on its back side. The first end battery cell of the second battery string 200 (e.g., Figure 2 The battery cell shown on the left end has a second end solder strip 201 on its back side, and the second end solder strip 201 extends outward from the first end of the second battery cell.

[0055] like Figure 1As shown, the first end cell of the first battery string 100 has multiple first end solder strips 101 and multiple first intermediate solder strips 102, and the first end solder strips 101 and the first intermediate solder strips 102 are arranged alternately in the width direction of the battery string. All first end solder strips 101 are connected to one of the positive and negative terminals of the first end cell, and all first intermediate solder strips 102 are connected to the other of the positive and negative terminals of the first end cell. Furthermore, the first end solder strips 101 are only connected to the first end cell, while the first intermediate solder strips 102 are connected in series with the first end cell and adjacent cells.

[0056] Similarly, such as Figure 2 As shown, the first end cell of the second battery string 200 has multiple second end solder strips 201 and multiple second intermediate solder strips 202, and the second end solder strips 201 and second intermediate solder strips 202 are arranged alternately in the width direction of the battery string. All second end solder strips 201 are connected to one of the positive and negative terminals of the first end cell, and all second intermediate solder strips 202 are connected to the other of the positive and negative terminals of the first end cell. Furthermore, the second end solder strips 201 are only connected to the first end cell, while the second intermediate solder strips 202 are connected in series with the first end cell and adjacent cells.

[0057] S2. Provide busbar assembly 300, such as Figure 6 and Figure 7 As shown, the busbar assembly 300 includes an insulating film strip 301, a busbar 302 located on a first side of the insulating film strip 301, and a plurality of metal sheets 303 located on a second side of the insulating film strip 301. The metal sheets 303 are arranged at intervals along the length of the insulating film strip 301. The insulating film strip 301 is provided with hollow portions 304 corresponding to each metal sheet 303. The metal sheets 303 located in each hollow portion 304 are welded to the busbar 302 at a first temperature.

[0058] S3. Place the first battery string 100 and the second battery string 200 along the length direction of the battery strings (e.g., the X direction), as follows: Figures 3 to 5 As shown, the protruding portion of the second end solder strip 201 is placed on the back of the first end battery cell of the first battery string 100, and corresponds one-to-one with the first end solder strip 101.

[0059] Figure 8 In the illustrated embodiment, six pairs of first battery strings 100 and second battery strings 200 are arranged along the width direction of the battery strings (e.g., the Y direction). Of course, in other embodiments, other numbers of pairs of first battery strings 100 and second battery strings 200 may be arranged depending on the specific structure of the photovoltaic module to be fabricated.

[0060] S4, such as Figures 8 to 10As shown, the busbar assembly 300 is placed on the back of the first end battery cell of the first battery string 100, so that each metal piece 303 of the busbar assembly 300 is placed on top of each first end solder strip 101 in a one-to-one correspondence, and each metal piece 303 is bonded to a pair of first end solder strips 101 and a second end solder strip 201 by adhesive.

[0061] The insulating film 301 of the busbar assembly 300 provides insulation between the busbar 302 and other solder strips (i.e., each first intermediate solder 102) on the first end of the first battery cell of the first battery string 100, thereby preventing short circuits.

[0062] Figure 8 In the illustrated embodiment, four busbar assemblies 300 are placed along the width direction (e.g., the Y direction) of the battery string. Counting from top to bottom along the width direction (e.g., the Y direction) of the battery string, the first busbar assembly 300 is placed on the back of the first end battery cell of the first battery string 100, and is used to connect the solder strips of the first pair of first battery strings 100 and the second battery string 200. The second busbar assembly 300 is placed on the back of the first end battery cells of the second and third battery strings 100, and is used to connect the solder strips of the second and third pairs of first battery strings 100 and the second battery string 200. The third busbar assembly 300 is placed on the back of the first end battery cells of the fourth and fifth battery strings 100, and is used to connect the solder strips of the fourth and fifth pairs of first battery strings 100 and the second battery string 200. The fourth busbar assembly 300 is placed on the back of the first end cell of the sixth first battery string 100 and is used to connect the solder strips of the sixth pair of first battery strings 100 and second battery strings 200.

[0063] In other embodiments, depending on the specific structure of the photovoltaic module to be prepared, other numbers of busbar modules 300 may be placed in the middle.

[0064] S5. Lamination is performed at a second temperature, so that each metal sheet 303 of the busbar assembly 300 is welded to the corresponding first end solder strip 101 and second end solder strip 201; the second temperature is lower than the first temperature.

[0065] It should be noted that there is no strict execution order between steps S1 and S2. Step S1 may be performed before step S2, or step S2 may be performed before step S1, or steps S1 and S2 may be performed simultaneously.

[0066] The photovoltaic module manufacturing method provided in this application first welds the busbar 302, insulating film strip 301, and several metal sheets 303 separately at a first temperature to prepare a busbar module 300. This helps to achieve reliable welding between the busbar 302 and the metal sheets 303 at a higher temperature. The insulating film strip 301 ensures that after the busbar module 300 is placed on the back of the first end cell of the first cell string 100, the busbar 302 is insulated from another set of solder strips (i.e., each first intermediate solder strip 102) on the back of the first end cell, excluding the first end solder strip 101.

[0067] By adhesively bonding the metal sheet 303 in the busbar assembly 300 to a pair of first end welding strips 101 and second end welding strips 201, the connection between the busbar assembly 300 and the welding strips is achieved, avoiding the risk of cell cracking caused by the compression welding method, and realizing the positioning between the metal sheet 303 and the welding strips, ensuring that the metal sheet and the welding strips can be accurately welded during lamination.

[0068] Furthermore, by laminating at a second temperature lower than the first temperature, on the one hand, secondary welding can be avoided at the welding points between the busbar 302 and the metal strip 303 during lamination; on the other hand, welding connection between the metal strip 303 and the corresponding solder strip can be achieved. Moreover, the metal strip 303, as the connection medium between the busbar and the solder strip, can improve the connection reliability between the busbar 302 and the solder strip, ultimately ensuring the reliability of the component.

[0069] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the first end solder strip 101 of the first battery string 100 does not extend outward from the first end battery sheet of the first battery string 100. That is, when arranging the first battery string 100 and the second battery string 200 in pairs, it is only necessary to place the protruding part of the second end solder strip 201 on the back of the first end battery sheet of the first battery string 100.

[0070] like Figure 5 As shown, in some other embodiments, the first end solder strip 101 of the first battery string 100 also extends outwards from the first end battery cell of the first battery string 100. When arranging the paired first battery strings 100 and second battery strings 200, the first end solder strip 101 also needs to be placed on the back of the first end battery cell of the second battery string 200. This arrangement enables the first battery string 100 and the second battery string 200 to be battery strings of the same structure. That is, only a single-structure battery string needs to be prepared according to a unified production process to obtain the final photovoltaic module, thereby reducing the complexity of battery string preparation and improving production efficiency.

[0071] In some embodiments, in step S2, copper foil is used as the metal sheet 303 of the busbar assembly 300. Copper foil has excellent conductivity and ductility. When soldering at the first temperature, the copper foil can form a strong, low-resistance solder joint with the busbar 302, thereby achieving stable and reliable soldering. When laminating at the second temperature, the copper foil can form a reliable solder connection with the first end solder strip and the second end solder strip, ultimately ensuring an unobstructed current conduction path from the solder strip to the copper foil and then to the busbar.

[0072] In some embodiments, the first temperature in step S2 is higher than 200°C, and the second temperature in step S5 is lower than 160°C. Using a first temperature higher than 200°C to weld the busbar 302 and the metal sheet 303 ensures a reliable weld connection between them. Using a second temperature lower than 160°C for laminating the battery string allows for a weld connection between the metal sheet 303 and the corresponding solder strip, and also prevents secondary welding at the weld points between the busbar 302 and the metal sheet 303.

[0073] In some embodiments, in step S1, the first battery string 100 and the second battery string 200 are both formed by connecting battery cells in series with solder ribbons, specifically including: connecting the battery cells and solder ribbons in series by adhesive bonding to obtain the first battery string 100 or the second battery string 200.

[0074] The solar cells and solder ribbons are connected in series by adhesive bonding, which avoids thermal damage to the solar cells caused by high-temperature welding. This series connection method is especially suitable for solar cells that are not resistant to high temperatures and solar cells without main grids.

[0075] To achieve series connection of the battery cells and solder strips using adhesive bonding, any of the following three methods can be used:

[0076] The first implementation involves pre-applying adhesive to the solder ribbon laying path on the battery cell. Then, the solder ribbon and the glued battery cells are laid and stacked according to a predetermined stringing rule, and the adhesive is cured, so that the solder ribbon is bonded to the battery cell through the adhesive on the corresponding battery cell to form a battery string.

[0077] The second implementation method involves first laying and stacking the solder ribbons and battery cells according to a predetermined stringing rule. Then, adhesive is applied to the stacked solder ribbons and the adhesive is cured, thereby bonding the solder ribbons to the corresponding battery cells to form a battery string.

[0078] The third implementation method involves first laying and stacking the solder ribbons and battery cells according to a predetermined stringing rule. Then, an adhesive film is laid on the stacked solder ribbons and heated to bond the solder ribbons to the corresponding battery cells, forming a battery string.

[0079] All three implementation methods described above can achieve rapid bonding of battery cells and solder ribbons into strings, while ensuring the quality of the battery cell stringing. In the first and second implementation methods, the adhesive can be applied via a dispensing head, screen printing, or spraying; the applied adhesive can be in the form of dots or strips; the adhesive can be UV adhesive or thermosetting adhesive; when using UV adhesive, curing can be achieved by UV light exposure; when using thermosetting adhesive, curing can be achieved by heating in a light box.

[0080] In some embodiments, in step S4, before placing the busbar assembly 300 onto the back of the first end cell of the first cell string 100, the photovoltaic module manufacturing method of this application further includes: applying adhesive to the metal sheet 303 of the busbar assembly 300, or applying adhesive to the first end solder strip 101 and the second end solder strip 201. Both of these adhesive application methods can bond the paired first end solder strips 101 and second end solder strips 201 to the corresponding metal sheets.

[0081] The adhesive applied to the metal sheet 303, or to the first end solder strip 101 and the second end solder strip 201, can be a conductive adhesive. After the busbar assembly 300 is placed on the back of the first end battery cell of the first battery string 100, the adhesive not only achieves pre-fixation of the metal sheet to the corresponding first end solder strip 101 and second end solder strip 201, but also achieves conductive connection between the metal sheet and the corresponding first end solder strip 101 and second end solder strip 201. When lamination is performed at a second temperature, the metal sheet and the corresponding first end solder strip 101 and second end solder strip 201 are then welded together.

[0082] Of course, the adhesive applied to the metal sheet 303, or to the first end solder strip 101 and the second end solder strip 201, can also be a non-conductive adhesive. After the busbar assembly 300 is placed on the back of the first end battery cell of the first battery string 100, the adhesive is used to pre-fix the metal sheet to the corresponding first end solder strip 101 and second end solder strip 201, thereby ensuring that a high-quality welded connection is formed between the metal sheet and the corresponding first end solder strip 101 and second end solder strip 201 when lamination is performed at the second temperature, avoiding poor soldering.

[0083] The adhesive can be applied to the metal sheet 303, or to the first end solder strip 101 and the second end solder strip 201 using a dispensing head.

[0084] like Figure 6 and Figure 7 As shown, in some embodiments, providing the busbar assembly in step S2 includes:

[0085] Several through holes are made at intervals along the length of the insulating film strip 301 to form several hollow parts 304.

[0086] The busbar 302 is placed on the first side of the insulating film strip 301, such that the busbar 302 covers each through hole.

[0087] Metal sheets 303 are provided one-to-one at the through-hole positions on the second side of the insulating film strip 301.

[0088] The metal sheets 303 are welded to the busbar 302 at the first temperature.

[0089] In some embodiments, such as Figure 1 and Figure 2 As shown, the second end of the first battery string 100 has a battery cell (e.g., Figure 1 The leftmost cell shown in the diagram has a third end solder strip 103 on its back side, and the second cell of the second battery string 200 has a fourth end solder strip 203 on its back side.

[0090] like Figure 1 As shown, the second-end battery cell of the first battery string 100 has multiple third end solder strips 103 and multiple third intermediate solder strips 104, which are arranged alternately in the width direction of the battery string. All third end solder strips 103 are connected to either the positive or negative terminal of the second-end battery cell, and all third intermediate solder strips 104 are connected to the other terminal of the second-end battery cell. Furthermore, the third end solder strips 103 are only connected to the second-end battery cell, while the third intermediate solder strips 104 are connected in series with the second-end battery cell and adjacent battery cells.

[0091] Similarly, such as Figure 2 As shown, the second end cell of the second battery string 200 has multiple fourth end solder strips 203 and multiple fourth intermediate solder strips 204, and the fourth end solder strips 203 and fourth intermediate solder strips 204 are arranged alternately in the width direction of the battery string. All fourth end solder strips 203 are connected to one of the positive and negative terminals of the second end cell, and all fourth end solder strips 203 are connected to the other of the positive and negative terminals of the second end cell. Furthermore, the fourth end solder strips 203 are only connected to the first end cell, while the fourth intermediate solder strips 204 are connected in series with the second end cell and its adjacent cells.

[0092] The photovoltaic module manufacturing method of this application also includes:

[0093] S6. The busbar assembly is placed on the back of the second end battery cells of at least two first battery strings 100, so that each metal piece 303 of the busbar assembly 300 is placed on top of each third end solder strip 103 in a one-to-one correspondence, and each metal piece 303 is bonded to a corresponding third end solder strip 103 by adhesive. Each first battery string 100 is placed side by side along the width direction of the battery string.

[0094] The busbar assembly 300 is placed on the back of the second end battery cells of at least two second battery strings 200, such that each metal piece 303 of the busbar assembly 300 is placed on top of each fourth end solder strip 203, and each metal piece 303 is bonded to a corresponding fourth end solder strip 203 by adhesive. Each second battery string 200 is placed side by side along the width direction of the battery string.

[0095] Among them, the busbar assembly 300, which is placed on the back of the second end battery cell of the first battery string 100, has an insulating film strip 301 that insulates the busbar 302 from other solder strips (i.e. each third intermediate solder strip 104) on the second end battery cell of the first battery string 100, thereby avoiding short circuits.

[0096] The busbar assembly 300, which is placed on the back of the second end cell of the second battery string 200, has an insulating film strip 301 that insulates the busbar 302 from other solder strips (i.e., each fourth intermediate solder strip 204) on the second end cell of the second battery string 200, thereby preventing short circuits.

[0097] Still with Figure 8 The photovoltaic module in the illustrated embodiment is used as an example. Along the width direction of the cell string (e.g., the Y direction), at the second end of each first cell string 100, the cell (e.g., ...) Figure 8 Three busbar assemblies 300 are placed on the back of the battery cell (located at the left end) shown in the figure. Counting from top to bottom along the width direction of the battery string (e.g., the Y direction), the first busbar assembly 300 is placed on the back of the second-end battery cells of the first and second battery strings 100. The second busbar assembly 300 is placed on the back of the second-end battery cells of the third and fourth battery strings 100. The third busbar assembly 300 is placed on the back of the second-end battery cells of the fifth and sixth battery strings 100.

[0098] Similarly, along the width direction of the battery string (e.g., the Y direction), at the second end of each second battery string 200, the battery cell (e.g., ...) Figure 7 Three busbar assemblies 300 are placed on the back of the battery cell (located at the right end) shown in the figure. Counting from top to bottom along the width direction of the battery string (e.g., the Y direction), the first busbar assembly 300 is placed on the back of the second-end battery cells of the first and second second battery strings 200. The second busbar assembly 300 is placed on the back of the second-end battery cells of the third and fourth second battery strings 200. The third busbar assembly 300 is placed on the back of the second-end battery cells of the fifth and sixth second battery strings 200.

[0099] In other embodiments, depending on the specific structure of the photovoltaic module to be prepared, other numbers of busbar components 300 may be placed at both ends.

[0100] S7. Heating is performed at a second temperature so that each metal piece 303 of the busbar assembly 300 is welded to the corresponding third end weld strip 203 or fourth end weld strip 204.

[0101] It should be noted that steps S6 and S4 can be performed simultaneously. Step S7 can be performed simultaneously with step S5. In fact, when laminating the arranged components, steps S5 and S7 are completed simultaneously.

[0102] By implementing steps S6 and S7, the busbars at both ends of the photovoltaic module are welded.

[0103] Similarly, by adhesively bonding the metal sheet 303 in the busbar assembly 300 to the third end solder strip 103 or the fourth end solder strip 203, the connection between the busbar assembly 300 and the solder strip is achieved, avoiding the risk of cell cracking caused by the compression welding method, and realizing the positioning between the metal sheet 303 and the solder strip, ensuring that the metal sheet and the solder strip can be accurately welded during lamination.

[0104] Furthermore, by laminating at a second temperature lower than the first temperature, on the one hand, secondary welding can be avoided at the welding points between the busbar 302 and the metal strip 303 during lamination; on the other hand, welding connection between the metal strip 303 and the corresponding solder strip can be achieved. Moreover, the metal strip 303, as the connection medium between the busbar and the solder strip, can improve the connection reliability between the busbar 302 and the solder strip, ultimately ensuring the reliability of the component.

[0105] This application also provides a photovoltaic module, which is manufactured by the photovoltaic module manufacturing method provided in any of the above embodiments. The photovoltaic module provided in this application uses a metal sheet as the connection medium between the busbar and the solder strip, which can improve the connection between the busbar and the solder strip via the metal sheet, improve the connection reliability between the busbar and the solder strip, and ultimately ensure the reliability of the photovoltaic module.

[0106] For further details on the specific structure of photovoltaic modules, please refer to the relevant descriptions in the previous embodiments of the photovoltaic module manufacturing method, which will not be repeated here.

[0107] This application provides a sufficiently detailed and specific description. Those skilled in the art should understand that the descriptions in the embodiments are merely exemplary, and all changes made without departing from the true spirit and scope of this application should fall within its protection scope. The scope of protection claimed in this application is defined by the claims, not by the above descriptions in the embodiments. Without contradiction, some optional components in one embodiment can also be used in another embodiment, and some preferred structures of the same component in one embodiment are also applicable to another embodiment. Furthermore, there may be slight differences in the wording of the names of certain components in different embodiments; these slight differences will not affect the understanding of the technical solution of the present invention by those skilled in the art.

Claims

1. A method for manufacturing a photovoltaic module, characterized in that, The photovoltaic module manufacturing method includes: A first battery string and a second battery string are provided. Both the first battery string and the second battery string are formed by connecting battery cells in series with solder strips. The battery cells are back-contact battery cells. The first battery cell of the first battery string has a first end solder strip on its back side. The first battery cell of the second battery string has a second end solder strip on its back side, and the second end solder strip extends outward from the first battery cell of the second battery string. A busbar assembly is provided, the busbar assembly including an insulating film strip, a busbar located on a first side of the insulating film strip, and a plurality of metal sheets located on a second side of the insulating film strip. The metal sheets are arranged at intervals along the length direction of the insulating film strip. The insulating film strip is provided with hollowed-out portions corresponding to each of the metal sheets. The metal sheets located at each of the hollowed-out portions are welded to the busbar at a first temperature. The first battery string and the second battery string are placed along the length of the battery string, and the protruding part of the second end solder strip is placed on the back of the first end battery piece of the first battery string, and corresponds one-to-one with the first end solder strip. The busbar assembly is placed on the back of the first end battery cell of the first battery string, such that each metal piece of the busbar assembly is placed on top of each first end solder strip, and each metal piece is bonded to a pair of first end solder strips and a second end solder strip by adhesive. A second temperature is used for lamination, so that each of the metal sheets of the busbar assembly is welded to the corresponding first end solder strip and second end solder strip; The second temperature is lower than the first temperature.

2. The photovoltaic module manufacturing method as described in claim 1, characterized in that, The first end solder strip extends outward from the first end of the first battery cell of the first battery string. After the first battery string and the second battery string are placed along the length of the battery string, the first end solder strip overlaps the back of the first end of the second battery cell; or, The first end solder strip does not extend outwards beyond the first end cell of the first battery string.

3. The photovoltaic module manufacturing method as described in claim 1, characterized in that, The metal sheet is copper foil.

4. The photovoltaic module manufacturing method as described in claim 1, characterized in that, Both the first battery string and the second battery string are formed by connecting battery cells in series with solder strips, including: connecting the battery cells and solder strips in series with adhesive to obtain the first battery string or the second battery string.

5. The photovoltaic module manufacturing method as described in claim 4, characterized in that, The step of bonding the battery cells and solder strips in series using adhesive includes: Adhesive is applied along the solder ribbon laying path on the battery cell; the solder ribbons and the glued battery cells are laid and stacked according to a predetermined stringing rule, and the adhesive is cured so that the solder ribbons are bonded to the battery cells by the adhesive on the corresponding battery cells; or, The solder ribbons and solar cells are laid and stacked according to a predetermined stringing pattern; adhesive is applied to the stacked solder ribbons, and the adhesive is cured, so that the solder ribbons are bonded to the corresponding solar cells by the adhesive; or, The solder ribbons and battery cells are laid and stacked according to a predetermined stringing rule; an adhesive film is laid on the stacked solder ribbons and heated to bond the solder ribbons to the corresponding battery cells.

6. The photovoltaic module manufacturing method according to claim 1, characterized in that, Before placing the busbar assembly onto the back of the first end cell of the first cell string, the photovoltaic module manufacturing method further includes: Apply adhesive to the metal sheet of the busbar assembly, or, Apply adhesive to the first end solder strip and the second end solder strip.

7. The photovoltaic module manufacturing method according to claim 1, characterized in that: The first temperature is above 200°C, and the second temperature is below 160°C.

8. The photovoltaic module manufacturing method as described in claim 1, characterized in that: The provided busbar assembly includes: A plurality of through holes are made at intervals along the length of the insulating film strip to form a plurality of the aforementioned hollowed-out portions; The busbar is placed on the first side of the insulating film strip, such that the busbar covers each of the through holes; The metal sheets are arranged one-to-one at the through holes on the second side of the insulating film strip; The metal sheets are welded to the busbar at a first temperature.

9. The photovoltaic module manufacturing method according to claim 1, characterized in that: The second end of the first battery string has a third end solder strip on the back side of the second end of the battery cell; the second end of the second battery string has a fourth end solder strip on the back side of the second end of the battery cell. The photovoltaic module manufacturing method further includes: The busbar assembly is placed on the back of the second end battery cells of at least two first battery strings, such that each metal piece of the busbar assembly is placed on top of each third end solder strip, and each metal piece is bonded to a corresponding third end solder strip by adhesive. Each first battery string is placed side by side along the width direction of the battery string. The busbar assembly is placed on the back of the second end battery cells of at least two second battery strings, such that each metal piece of the busbar assembly is placed on top of each fourth end solder strip, and each metal piece is bonded to a corresponding fourth end solder strip by adhesive. Each second battery string is placed side by side along the width direction of the battery string. A second temperature is used for heating, so that each of the metal sheets of the busbar assembly is welded to the corresponding third end solder strip or the fourth end solder strip.

10. A photovoltaic module, characterized in that, The photovoltaic module is manufactured by the photovoltaic module manufacturing method according to any one of claims 1 to 9.

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