A photovoltaic module and a method of manufacturing the same

Abstract

This invention discloses a photovoltaic module and its manufacturing method. The photovoltaic module may include: multiple grid-less solar cells and a conductive component for connecting the multiple grid-less solar cells in series. The conductive component includes: a conductive solder strip having at least one plane, a groove structure disposed on one plane of the conductive solder strip, and an adhesive conductive layer disposed within the groove structure. The extension direction of the conductive solder strip is perpendicular to the fine grid lines of the grid-less solar cells; the groove structure is opposite to the grid-less solar cells; and the adhesive conductive layer is fixedly connected to the fine grid lines of the grid-less solar cells. This photovoltaic module replaces the low-temperature solder strip with a conductive component to solve problems such as high contact resistance, poor soldering, poor contact, and EL blackening caused by the low-temperature solder strip, effectively improving the efficiency of the photovoltaic module.

Description

Technical Field

[0001] This invention relates to a photovoltaic module and its manufacturing method. Background Technology

[0002] In the process of manufacturing photovoltaic modules using solar cells, in order to pursue higher module output power, low-temperature solder ribbons are generally used to connect gridless solar cells in series. This is because low-temperature solder ribbons can weld fine grids at low temperatures. However, due to the poor stability of the connection between the low-temperature solder ribbon and the fine grid, the low-temperature solder ribbon is often used with adhesive / curing adhesive or film to connect them in series, which can easily cause large contact resistance, resulting in problems such as blackening of the EL (electroluminescence electrode) and poor contact between the low-temperature solder ribbon and the fine grid, which affect the efficiency and subsequent reliability of the photovoltaic module. Summary of the Invention

[0003] In view of this, the present invention provides a photovoltaic module and its manufacturing method. The photovoltaic module replaces the low-temperature solder ribbon with a conductive component to effectively reduce the contact resistance between the conductive component and the gridless cell, thereby solving the problems of EL blackening and poor contact with the fine grid caused by the series connection of the low-temperature solder ribbon, and effectively improving the efficiency and reliability of the photovoltaic module.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] In a first aspect, the present invention provides a photovoltaic module, comprising: a plurality of grid-less solar cells and a conductive element for connecting the plurality of grid-less solar cells in series, wherein,

[0006] The conductive component includes: a conductive solder strip comprising at least one plane, a groove structure disposed on one plane of the conductive solder strip, and an adhesive conductive layer disposed within the groove structure; wherein...

[0007] The extension direction of the conductive solder strip is perpendicular to the fine grid lines of the gridless solar cell;

[0008] The groove structure is opposite to the gridless solar cell;

[0009] The adhesive conductive layer is fixedly connected to the fine grid lines of the gridless solar cell.

[0010] Secondly, embodiments of the present invention provide a method for preparing a photovoltaic module according to the first aspect embodiment, comprising:

[0011] Repeat steps A and B until a pre-connected battery string is obtained:

[0012] Step A: Print and bond a conductive layer inside the pre-set groove on the flat surface of one end of the solder strip.

[0013] Step B: Place the solder ribbon with the printed adhesive conductive layer on the gridless solar cell, wherein the extension direction of the solder ribbon is perpendicular to the direction of the fine grid lines of the gridless solar cell. Then, continue to print the adhesive conductive layer in the groove at the other end of the solder ribbon and cover the gridless solar cell on the solder ribbon.

[0014] Step C: Heat the pre-connected battery string to cure the printed adhesive conductive layer, wherein the heating temperature is 140-170°C, to obtain the battery string formed by connecting the gridless battery cells.

[0015] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects:

[0016] In the photovoltaic module provided by this invention, the conductive component for connecting the gridless solar cells in series is fixedly connected and electrically connected to the fine grid lines by an adhesive conductive layer disposed in its groove structure. That is, the conductive component is fixed and electrically connected to the fine grid lines of the gridless solar cell by means of the adhesive conductive layer. Therefore, the main body of the conductive component - the conductive ribbon - can be a ribbon with a relatively high melting point temperature. That is, the adhesive connection between the adhesive conductive layer and the fine grid lines replaces the welding connection between the low-temperature ribbon and the fine grid lines. Compared with the welding connection, the adhesive connection between the adhesive conductive layer and the fine grid lines does not produce problems such as over-soldering or cold solder joints. Therefore, the conductive component replaces the low-temperature ribbon, which can reduce the contact resistance between the conductive component and the gridless solar cell and avoid problems such as poor contact with the fine grid caused by cold solder joints or over-soldering, thereby avoiding phenomena such as EL blackening, so as to ensure the efficiency and reliability of the photovoltaic module. Attached Figure Description

[0017] Figure 1 This is a plan view of a portion of the structure of a photovoltaic module according to an embodiment of the present invention;

[0018] Figure 2 This corresponds to the embodiments of the present invention. Figure 1 The cross-sectional structure diagram of the relative positions of the fine grid lines on the front side of the gridless solar cell (with dashed line aa), the conductive solder strips connected to the fine grid lines on the front side, and the adhesive conductive layer.

[0019] Figure 3 This is a cross-sectional structural schematic diagram showing another relative positional relationship between the fine grid lines on the back side of the gridless solar cell according to an embodiment of the present invention, the conductive solder strips connected to the fine grid lines on the back side, and the adhesive conductive layer.

[0020] Figure 4 This is a cross-sectional schematic diagram of the conductive solder strip of the first structure connecting adjacent gridless solar cells according to an embodiment of the present invention.

[0021] Figure 5This is a cross-sectional structural schematic diagram of a first conductive component based on a first-type conductive solder strip according to an embodiment of the present invention.

[0022] Figure 6 This is a cross-sectional schematic diagram of the conductive solder strip of the second structure connecting adjacent gridless solar cells according to an embodiment of the present invention.

[0023] Figure 7 This is a cross-sectional structural schematic diagram of a second conductive component based on a conductive solder strip of the second structure according to an embodiment of the present invention.

[0024] Figure 8 This is a cross-sectional structural diagram showing the relationship between a third type of conductive component and a gridless solar cell according to an embodiment of the present invention.

[0025] Figure 9 According to the embodiments of the present invention, along Figure 2 A schematic diagram of the cross-section of the first structure of the conductive component, cut out by the dashed line AA in the figure;

[0026] Figure 10 This is a cross-sectional schematic diagram of a second structure of a conductive element according to an embodiment of the present invention;

[0027] Figure 11 This is a cross-sectional schematic diagram of a third structure of a conductive element according to an embodiment of the present invention;

[0028] Figure 12 This is a cross-sectional schematic diagram of the fourth structure of the conductive element according to an embodiment of the present invention.

[0029] The attached figures are labeled as follows:

[0030] 10-Gridless solar cell; 11-Fine grid line; 12-Second fine grid line; 20-Conductive component; 21-Conductive solder strip; 22-Groove structure; 23-Adhesive conductive layer; 24-Secondary grid line; 25-Adhesive layer. Detailed Implementation

[0031] The cross-section involved in the embodiments of this invention refers to the section along the extension direction of the conductive component or conductive solder strip (e.g., Figure 1 The dashed line aa) shown represents a portion of the cut surface obtained by cutting the photovoltaic module.

[0032] The cross section involved in the embodiments of this invention refers to the section along the direction perpendicular to the extension of the conductive component or the conductive solder strip (e.g., Figure 2 The dashed line AA shows the partial cut surface obtained by cutting a photovoltaic module or conductive component.

[0033] In the embodiments of this invention, the terms "first," "second," etc., are used to distinguish different structures or components or different positions of the same structure, and are not intended to limit the number or order of structures or components. For example, the first and second sub-fine grid lines in the embodiments of this invention are generally used to distinguish sub-fine grid lines located in different positions and with different connection structures. For instance, the first sub-fine grid line is located on the conductive solder strip, while the second sub-fine grid line is directly connected to the adjacent fine grid line.

[0034] To address the issues of high positioning accuracy requirements, easy deviation of the low-temperature solder ribbon, and poor contact with fine grid lines in existing photovoltaic modules where the connection between the gridless solar cells and the low-temperature solder ribbon is achieved via adhesive dots, this invention provides a photovoltaic module and its manufacturing method to solve the aforementioned problems of photovoltaic modules composed of gridless solar cells. Figure 1 This diagram shows a planar structural schematic of a photovoltaic module provided in an embodiment of the present invention. Figure 2 This illustrates the embodiments of the present invention corresponding to... Figure 1 The diagram shows a cross-sectional view of the relative positions of the fine grid lines on the front side of the gridless solar cell (denoted by dashed line aa), the conductive solder strips connected to the fine grid lines, and the adhesive conductive layer. Figure 3 This is a cross-sectional structural diagram showing another relative positional relationship between the fine grid lines on the back side of the gridless solar cell according to an embodiment of the present invention, the conductive solder strips connected to the fine grid lines on the back side, and the adhesive conductive layer. Figure 4 and Figure 6 Schematic diagrams showing cross-sectional structures of conductive solder strips with different structures;

[0035] Figure 5 and Figure 7 Schematic diagrams of cross-sectional structures of conductive components with different structures are shown; Figure 8 A cross-sectional structural diagram showing the relationship between the third type of conductive component and the gridless solar cell is shown. Figures 9 to 12 The diagram shows different cross-sectional structures of the conductive component.

[0036] like Figures 1 to 3 and Figure 8 As shown, this embodiment of the invention provides a photovoltaic module. The photovoltaic module may include: a plurality of grid-less solar cells 10 and a conductive element 20 for connecting the plurality of grid-less solar cells 10 in series, wherein...

[0037] The conductive component 20 includes: a conductive solder strip 21 having at least one plane, a groove structure 22 disposed on one plane of the conductive solder strip 21, and an adhesive conductive layer 23 disposed within the groove structure 22; wherein,

[0038] The extension direction of the conductive solder strip 21 is perpendicular to the fine grid lines 11 of the gridless solar cell 10;

[0039] The groove structure 22 is opposite to the gridless solar cell 10;

[0040] The conductive adhesive layer 23 is fixedly connected to the fine grid lines 11 of the gridless solar cell 10.

[0041] Among them, such as Figures 2 to 12 As shown, the area where the conductive solder strip 21 contacts the gridless solar cell is a flat plane, not an arc shape, to ensure that the adhesive conductive layer 23 can fully adhere to the fine grid lines. Simultaneously, this allows the conductive component 20 to have a relatively large contact area with the gridless solar cell 10, and the bottom groove for setting the adhesive conductive layer 23 ensures sufficient amount of adhesive conductive layer 23 and proper adhesion between the conductive solder strip and the gridless solar cell 10, thus guaranteeing the electrical and mechanical reliability of the series connection.

[0042] Since the conductive component used for connecting gridless solar cells is fixedly and electrically connected to the fine grid lines through an adhesive conductive layer set in its groove structure, that is, the conductive component is fixed and electrically connected to the fine grid lines of the gridless solar cell by means of the adhesive conductive layer, the main body of the conductive component - the conductive ribbon - can be a ribbon with a relatively high melting point temperature. That is, the adhesive connection between the adhesive conductive layer and the fine grid lines replaces the welding connection between the low-temperature ribbon and the fine grid lines. Compared with the welding connection, the adhesive connection between the adhesive conductive layer and the fine grid lines does not produce problems such as over-soldering or cold solder joints. Therefore, this conductive component replaces the low-temperature ribbon, which can reduce the contact resistance between the conductive component and the gridless solar cell and avoid problems such as poor contact with the fine grid caused by cold solder joints or over-soldering, thereby avoiding phenomena such as EL blackening, so as to ensure the efficiency and reliability of photovoltaic modules.

[0043] In addition, compared to fixing the low-temperature solder strip with adhesive dots between adjacent fine grid lines, the conductive component provided in this application has lower requirements for the positioning accuracy of the production equipment because the adhesive conductive layer is located on the conductive component, which can effectively improve the production efficiency of photovoltaic modules.

[0044] In the photovoltaic module provided in the embodiments of the present invention, the width of the fine grid lines 11 on the gridless cells can be 20 to 40 μm.

[0045] The fine grid line 11 has a height of 6 to 12 μm to meet the connection requirements with the conductive component, while also being able to conduct and collect current relatively well.

[0046] It is worth noting that the aforementioned photovoltaic modules also include a cover plate, a backsheet, and a busbar for series-parallel connected cell strings.

[0047] Among them, such as Figure 9 , Figure 11 and Figure 12 As shown, the cross-section of the groove structure 22 can be arc-shaped to ensure that the adhesive conductive layer 23 can be tightly attached to the inner wall of the groove structure 22.

[0048] Among them, such as Figures 9 to 12 As shown, the cross-section of the conductive solder strip can be any regular shape. In a preferred embodiment, the conductive solder strip 21 is a triangular solder strip, which makes the conductive solder strip 21 easy to obtain.

[0049] Specifically, the aforementioned adhesive conductive layer 23 can be formed of a thermosetting conductive adhesive material. The curing temperature of the thermosetting conductive adhesive material does not exceed 170°C, and the curing time does not exceed 60 seconds. This ensures that the power and other performance characteristics of the gridless solar cell are not affected during the thermosetting connection process between the adhesive conductive layer 23 and the gridless solar cell.

[0050] Furthermore, such as Figures 2 to 5 and Figure 8 As shown, the groove structure 22 of the conductive component 20 can be a planar through groove of the conductive solder strip 21; the groove structure 22 can also be as follows: Figure 6 and Figure 7 As shown, this is a segmented setup.

[0051] For the case where the groove structure 22 of the conductive component 20 is a through groove on a plane of the conductive solder strip 21, such as Figures 2 to 5 As shown, the adhesive conductive layer 23 can fill the through groove completely, or it can be as follows: Figure 8 As shown, the adhesive conductive layer 23 is segmented in the through groove, wherein each segment of the adhesive conductive layer 23 corresponds to a fine grid line 11 of the gridless cell 10.

[0052] For cases where the groove structure 22 is segmented, such as Figure 6 and Figure 7 As shown, multiple groove structures 22 are arranged in a plane on the conductive solder strip 21;

[0053] Multiple groove structures 22 are not interconnected; each groove structure 22 corresponds to a fine grid line 11 of the gridless cell 10.

[0054] By filling the groove structure 22 with the adhesive conductive layer 23, the process of establishing the connection between the conductive element 20 and the fine grid line 11 can avoid the adhesive conductive layer 23 overflowing and blocking the surface of the gridless cell. This makes the effective usable area of ​​the light-receiving surface of the gridless cell larger, thereby effectively improving the photoelectric conversion performance and service life of the photovoltaic module, while maintaining the aesthetic appearance of the photovoltaic module.

[0055] Furthermore, regarding such Figure 7 As shown, in the case where the adhesive conductive layer 23 is segmented, the conductive solder strip 21 further includes a first set of fine grid lines 24 located between adjacent adhesive conductive layers 23, wherein the segmented adhesive conductive layers 23 and the segmented first set of fine grid lines 24 are arranged alternately.

[0056] The first fine grid line 24 is integrally formed with the conductive solder strip 21. The setting of the first fine grid line 24 can effectively improve the current collection capability of the conductive component 20.

[0057] Furthermore, regarding the case where the adhesive conductive layer 23 is segmented within the through groove, such as... Figure 8 As shown, the secondary fine grid lines can also be directly fixed to the fine grid lines. Specifically, for the case where the adhesive conductive layer 23 is segmented within the through groove, a second secondary fine grid line 12 is intermittently provided in the direction perpendicular to the fine grid line 11 to connect every two adjacent fine grid lines 11, wherein...

[0058] When the adhesive conductive layer 23 is bonded to its corresponding fine grid line 11, the second set of fine grid lines 12 fills the groove structure 22 and connects to its adjacent adhesive conductive layer 23. This effectively improves the current collection capability of the photovoltaic module.

[0059] Furthermore, such as Figure 5 and Figure 7 As shown, the conductive solder strip 21 further includes an adhesive layer 25 disposed at both ends of the groove structure 22, wherein the adhesive layer 25 corresponds to the area of ​​the edge of the gridless cell 10 that is not covered by the fine grid lines 11. This further stabilizes the conductive solder strip 21, ensuring a stable connection between the conductive solder strip 21 and the fine grid lines 11 of the gridless cell 10, and preventing displacement of the conductive solder strip 21.

[0060] In addition, embodiments of the present invention also provide a conductive element 20 for connecting battery cells in series. For example... Figures 2 to 12 As shown, the conductive component 20 may include at least one planar conductive solder strip 21, a groove structure 22 disposed on one planar surface of the conductive solder strip 21, and an adhesive conductive layer 23 disposed within the groove structure 22; wherein, the adhesive conductive layer 23 is used for fixed connection with the fine grid lines 11 of the gridless solar cell 10.

[0061] Furthermore, embodiments of the present invention provide a method for manufacturing a photovoltaic module. This method for manufacturing a photovoltaic module may include:

[0062] Repeat steps A and B until a pre-connected battery string is obtained:

[0063] Step A: Print and bond conductive layer 23 inside the pre-set groove on the plane at one end of the solder strip;

[0064] For example, targeting Figure 4 The solder strip shown undergoes a process where a conductive layer 23 is first printed and bonded into the groove on the left side of the solder strip. For example... Figure 6 The solder strip shown in the figure first has a conductive layer 23 printed and bonded in the downward-facing groove through this step.

[0065] Step B: Lay multiple solder strips printed with adhesive conductive layer 23 on the gridless solar cell, wherein the extension direction of the solder strips is perpendicular to the direction of the fine grid lines of the gridless solar cell. Then, continue to print adhesive conductive layer 23 in the groove at the other end of the laid solder strips, and cover the gridless solar cell on the solder strips.

[0066] For example, multiple lines Figure 4 The left-side solder strip segment of the printed conductive layer 23 in the groove is laid onto the gridless solar cell; then, the conductive layer 23 is printed in the groove with the right-side segment of the solder strip facing upwards, and the gridless solar cell is laid on the right-side segment of the printed solder strip. For example, multiple such... Figure 6 The downward-facing groove shown is printed with a section of solder ribbon containing the adhesive conductive layer 23, which is then laid on the gridless solar cell. The adhesive conductive layer 23 is then printed in the groove with the right side of the solder ribbon facing upward, and the gridless solar cell is laid on the right side of the printed solder ribbon.

[0067] Step C: Heat the pre-connected battery string to cure the printed adhesive conductive layer 23, wherein the heating temperature is 140-170°C to obtain the battery string formed by connecting the gridless battery cells.

[0068] The above steps are provided only to help understand the method, structure, and core ideas of this invention. Those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A photovoltaic module, characterized in that, include: Multiple gridless solar cells (10) and conductive elements (20) for connecting multiple gridless solar cells (10) in series, wherein, The conductive element (20) includes: a conductive solder strip (21) having at least one plane, a groove structure (22) disposed on one plane of the conductive solder strip (21), and an adhesive conductive layer (23) disposed within the groove structure (22); wherein, The extension direction of the conductive solder strip (21) is perpendicular to the fine grid lines (11) of the gridless solar cell (10); The groove structure (22) is opposite to the gridless solar cell (10); The adhesive conductive layer (23) is fixedly connected to the fine grid lines (11) of the gridless solar cell (10); The groove structure (22) is a through groove in a plane of the conductive solder strip (21); The adhesive conductive layer (23) is segmented in the through groove, wherein each segment of the adhesive conductive layer (23) corresponds to a fine grid line (11) of the gridless solar cell (10). In a direction perpendicular to the fine grid line (11), a second set of fine grid lines (12) is intermittently provided for connecting every two adjacent fine grid lines (11), wherein, When the adhesive conductive layer (23) is bonded to its corresponding fine grid line (11), the second fine grid line (12) fills the groove structure (22) and is connected to the adhesive conductive layer (23) adjacent to it.

2. The photovoltaic module according to claim 1, characterized in that, The conductive solder strip (21) further includes: an adhesive layer (25) disposed at both ends of the groove structure (22), wherein, The adhesive layer (25) corresponds to the area of ​​the edge of the gridless cell (10) that is not covered by the fine grid lines (11).

3. The photovoltaic module according to claim 1, characterized in that, The width of the fine grid line (11) is 20~40μm; And / or, The height of the fine grid line (11) is 6~12μm; And / or, The cross-section of the groove structure (22) is arc-shaped; And / or, The conductive solder strip (21) is a triangular solder strip.

4. The photovoltaic module according to claim 1, characterized in that, The adhesive conductive layer (23) is formed of a thermosetting conductive adhesive material.

5. The photovoltaic module according to claim 4, characterized in that, The curing temperature of the thermosetting conductive adhesive material is not higher than 170°C, and the curing time is not more than 60 seconds.

6. The method for preparing a photovoltaic module according to any one of claims 1 to 5, characterized in that, include: Repeat steps A and B until a pre-connected battery string is obtained: Step A: Print and bond a conductive layer (23) inside the groove pre-set on the plane at one end of the solder strip. Step B: Place the solder ribbon printed with the adhesive conductive layer (23) on the gridless solar cell, wherein the extension direction of the solder ribbon is perpendicular to the direction of the fine grid line of the gridless solar cell. Then, continue to print the adhesive conductive layer (23) in the groove at the other end of the solder ribbon and cover the gridless solar cell on the solder ribbon. In the direction of the gridless solar cell perpendicular to the fine grid line (11), a second set of fine grid lines (12) for connecting each two adjacent fine grid lines (11) are provided at intervals. Step C: Heat the pre-connected battery string to cure the printed adhesive conductive layer (23), wherein the heating temperature is 140~170℃, to obtain the battery string formed by the gridless battery cells connected in series, and the second fine grid line (12) fills the groove structure (22) and is connected to the adjacent adhesive conductive layer (23).

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