Connection structure and method of solar cell string

Abstract

The invention provides a connecting structure and method of a solar cell string. The connecting structure comprises a cell piece, a welding strip, a glue point, an auxiliary grid and an electric connecting wire. The glue points and the auxiliary grids are respectively arranged on the surface of the battery piece, the welding strip is pre-fixed on the battery piece through the glue points, and the welding strip is electrically connected with the plurality of auxiliary grids; the electric connecting line is connected to the plurality of auxiliary grids. According to the battery pattern design of the gluing position provided by the scheme, in order to reduce the risk of poor contact caused by the overflow of glue to the secondary grid, a secondary grid electric connecting wire is designed on the secondary grid close to the gluing position; after glue application and before lamination, the welding strip enables welding flux to be melted to form good alloy contact with a battery grid line in a direct welding mode, the welding flux is not melted again during lamination, and the risk that a glue film permeates into a gap between the welding strip and a battery is reduced.

Description

[0001] This application is a divisional application of an invention patent application filed on October 28, 2022, with application number 202211335990.5 and invention name “A connection structure and method for a solar cell string”. Technical Field

[0002] The present invention relates to the field of photovoltaic technology, and in particular to a connection structure and method for a solar cell string. Background Art

[0003] As countries around the world accelerate their energy transition, the share of photovoltaics in clean energy continues to rise. Photovoltaic paste accounts for about 50% of the non-silicon cost of batteries, and reducing the unit consumption of silver paste will be an important direction for technological innovation.

[0004] At present, conventional photovoltaic cells all have a main grid design, which mainly serves to connect the welding strip electrically and mechanically, that is, the welding strip is fixed to the cell through the main grid, and the current is collected and transmitted to the welding strip. Generally, the main grid is printed with silver paste. With the popularization of multi-busbar batteries, the consumption of main grid silver paste is gradually increasing. It is necessary to adopt some new solutions to reduce the consumption of main grid. Summary of the invention

[0005] In view of this, the present invention provides a connection structure and method for a solar cell string, which reduces the silver paste consumption of the cell, reduces the battery cost, and improves the reliability of the connection between the soldering ribbon and the battery.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A connection structure of a solar cell string, comprising: a cell sheet, a welding ribbon, glue dots, a secondary grid and an electrical connection line; the glue dots and the secondary grid are respectively arranged on the surface of the cell sheet, the welding ribbon is pre-fixed to the cell sheet through the glue dots, and the welding ribbon is electrically connected to multiple secondary grids; the electrical connection line is connected to multiple secondary grids.

[0008] Preferably, the glue dots are conductive glue dots; the glue dots are located on the auxiliary grid, and the auxiliary grid provided with the glue dots is connected to the electrical connection line.

[0009] Preferably, at least one of the glue spots is a conductive glue spot; the glue spot is located between two adjacent sub-grids, and at least one of the sub-grids on both sides of the glue spot is connected to the electrical connection line.

[0010] Preferably, the glue dots are insulating glue dots; the glue dots are located on the auxiliary grid, and the auxiliary grid provided with the glue dots is connected to the electrical connection line.

[0011] Preferably, the glue dot is an insulating glue dot; the glue dot is located between two adjacent sub-grids, and at least one of the sub-grids on both sides of the glue dot is connected to the electrical connection line.

[0012] Preferably, two ends of the electrical connection line are respectively connected to the auxiliary grids on both sides of the glue point.

[0013] Preferably, a single one of the auxiliary grids on both sides of the glue point is connected to the adjacent auxiliary grid on the outer side of the same side through the electrical connection line.

[0014] Preferably, the sub-grids on both sides of the glue point are respectively connected to the sub-grids adjacent to the outer side of the same side through the electrical connection lines.

[0015] Preferably, the sub-grids on both sides of the glue spot are connected by the electrical connection line, and a single one of the sub-grids on both sides of the glue spot is connected to the adjacent sub-grid on the outside of the same side by the electrical connection line.

[0016] Preferably, the sub-grids on both sides of the glue spot are connected by the electrical connection line, and the sub-grids on both sides of the glue spot are respectively connected to the sub-grids adjacent to the outer side of the same side by the electrical connection line.

[0017] Preferably, the sub-grid provided with the glue dots is connected to the sub-grid adjacent to one side through the electrical connection line.

[0018] Preferably, the sub-grid provided with the glue dots is respectively connected to the sub-grids adjacent to the two sides through the electrical connection lines.

[0019] Preferably, the distance d1 from the glue point to the auxiliary grids on both sides is not less than 0.1 mm.

[0020] Preferably, the straight line where the electrical connection line is located intersects with the glue point and is completely covered by the welding tape.

[0021] Preferably, the straight line where the electrical connection line is located is staggered from the glue point, and the distance d2 between the electrical connection line and the glue point is less than or equal to 1 / 2 of the projection distance d3 of two adjacent glue points along the extension direction of the secondary grid.

[0022] Preferably, the width W1 of the glue dot is greater than or equal to the width W2 of the secondary grid, and the length L1 of the glue dot is greater than or equal to the width W3 of the welding strip.

[0023] Preferably, a projection length L4 of the electrical connection line in a direction perpendicular to the auxiliary grid is greater than or equal to a minimum distance between two adjacent auxiliary grids, and the projection length L4 is less than or equal to a maximum distance L3 between two outermost auxiliary grids.

[0024] A method for connecting a solar cell string adopts the connection structure of the solar cell string as described above, and after applying glue points and before lamination, comprises the following steps: pre-bonding the welding strip to the battery cell through the glue points; curing the glue points; welding a connector formed by the battery cell, the welding strip and the glue points, so that the welding strip forms an alloy contact with the auxiliary grid.

[0025] Preferably, the curing method includes: light irradiation and heat pressing.

[0026] Preferably, the welding methods include: infrared welding, hot air welding and induction heating, and the welding temperature is 130°C to 300°C.

[0027] Preferably, the curing is completed during the welding, or is performed during the welding preheating stage.

[0028] It can be seen from the above technical scheme that the connection structure and method of the solar cell string provided by the present invention, after gluing and before lamination, the solder strip is directly welded to make the solder melt and form a good alloy contact with the battery grid line, and the solder will not melt again during lamination, reducing the risk of the glue film penetrating into the gap between the solder strip and the battery; the present scheme also provides a battery graphic design at the gluing position, in order to reduce the risk of poor contact caused by overflow of glue onto the sub-grid, a sub-grid electrical connecting wire is designed on the sub-grid adjacent to the glue application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the structure of a solar cell string provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of the distance between the glue point and the auxiliary grid provided in an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the structures of various forms of electrical connecting wires provided by an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of a structure in which an electrical connection line provided in an embodiment of the present invention is far away from a glue point;

[0034] Figure 5 A schematic diagram of the structure of the connection structure of a solar cell string provided by an embodiment of the present invention;

[0035] Figure 6 A schematic diagram of the length of the electrical connection line provided in an embodiment of the present invention;

[0036] Figure 7 A flow chart of a method for connecting a solar cell string provided by an embodiment of the present invention;

[0037] Among them, 1 is the battery cell, 2 is the welding strip, 3 is the glue point, 4 is the auxiliary grid, and 5 is the electrical connection line. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The connection structure of the solar cell string provided in the embodiment of the present invention comprises: a solar cell 1, a welding ribbon 2, a glue point 3, a secondary grid 4 and an electrical connection line 5. The structure can refer to Figure 1 , Figure 5 and Figure 6 As shown;

[0040] The glue point 3 and the auxiliary grid 4 are respectively arranged on the surface of the battery cell 1, the welding tape 2 is pre-fixed to the battery cell 1 through the glue point 3, and the welding tape 2 is electrically connected to multiple auxiliary grids 4; it can be understood that the glue point 3 needs to be cured after pre-fixation;

[0041] The electrical connection wires 5 are connected to the plurality of sub-grids 4 .

[0042] It can be seen from the above technical scheme that the connection structure of the solar cell string provided by the embodiment of the present invention is designed with an electrical connection line 5 at the auxiliary grid 4, providing other channels between the auxiliary grids 4 to transmit current to the welding strip 2; when the auxiliary grid 4 and the welding strip 2 cannot effectively contact each other, the current can be transmitted to the auxiliary grid 4 connected thereto through the electrical connection line 5, and then transmitted to the welding strip 2, or directly transmitted to the welding strip 2 by the electrical connection line 5, thereby reducing the risk of poor contact caused by the overflow of the glue point 3 to the auxiliary grid 4; this scheme does not require a main grid, reduces the silver paste consumption of the battery cell, and reduces the battery cost; after applying the glue and before lamination, the welding strip is directly welded to melt the solder and form a good alloy contact with the battery grid line, and the solder will no longer melt again during lamination, thereby reducing the risk of the glue film penetrating into the gap between the welding strip and the battery.

[0043] The glue used for the glue point 3 can be either a conductive glue or an insulating glue without conductive ability. For the conductive glue, since it can conduct current, the glue application position is relative to the position of the secondary grid 4 on the surface of the battery cell 1, preferably on the secondary grid 4 line, and the current on this secondary grid 4 can be directly transmitted to the welding ribbon 2 through the conductive glue point 3. Its structure can be referred to Figure 2 As shown, the conductive first glue dot 31 is located on the auxiliary grid 4 , and the auxiliary grid 4 provided with the first glue dot 31 is connected to the electrical connection line 5 .

[0044] The conductive glue point 3 can also be located between two adjacent auxiliary grids 4. The structure can refer to Figure 2 As shown in the second glue point 32, the glue at this time mainly plays a connecting role; at least one of the sub-grids 4 on both sides of the second glue point 32 is connected to the electrical connection line 5, reducing the risk of poor contact caused by the second glue point 32 overflowing onto the sub-grid 4.

[0045] Non-conductive glue can also be applied to the auxiliary grid 4 line, but this auxiliary grid 4 needs to be processed to conduct the electrical connection line 5 so that the current on this auxiliary grid 4 can be normally conducted. Figure 2 As shown, the insulating first glue point 31 is located on the auxiliary grid 4 , and the auxiliary grid 4 provided with the first glue point 31 is connected to the electrical connection line 5 .

[0046] For the non-conductive glue point 3, it is preferably located between two adjacent auxiliary grids 4. Figure 2 As shown in the second glue dot 32 , at least one of the grids 4 on both sides of the second glue dot 32 is connected to the electrical connection line 5 .

[0047] Specifically, in one case, the two ends of the first electrical connection line 51 are respectively connected to the second sub-grid 42 and the third sub-grid 43 on both sides of the third glue point 33, such as Figure 3 As shown in the form of a.

[0048] In another case, a single one of the second sub-grid 42 and the third sub-grid 43 on both sides of the fourth glue point 34 (here, the second sub-grid 42) is connected to the first sub-grid 441 adjacent to the outside of the same side through the second electrical connection line 52, as shown in FIG. Figure 3 As shown in the b form.

[0049] In another case, the second sub-grid 42 and the third sub-grid 43 on both sides of the fifth glue point 35 are connected to the first sub-grid 41 and the fourth sub-grid 44 adjacent to the outside of the same side through the third electrical connection line 53 and the fourth electrical connection line 54, respectively. Figure 3 As shown in the c form.

[0050] In another case, the second sub-grid 42 and the third sub-grid 43 on both sides of the sixth glue point 36 are connected by the fifth electrical connection line 55, and a single one of the second sub-grid 42 and the third sub-grid 43 on both sides of the sixth glue point 36 (here, the second sub-grid 42) is connected to the first sub-grid 41 adjacent to the outside of the same side by the fifth electrical connection line 55. Figure 3 As shown in the d form.

[0051] And / or in another case, the second sub-grid 42 and the third sub-grid 43 on both sides of the seventh glue spot 37 are connected through the sixth electrical connection line 56, and the second sub-grid 42 and the third sub-grid 43 on both sides of the seventh glue spot 37 are respectively connected to the first sub-grid 41 and the fourth sub-grid 44 adjacent to the outside of the same side through the sixth electrical connection line 56, such as Figure 3 As shown in the e form.

[0052] In another case, the second sub-grid 42 provided with the eighth glue point 38 is connected to the first sub-grid 41 adjacent to one side through the seventh electrical connection line 57, such as Figure 3 The f form is shown in .

[0053] In another case, the second sub-grid 42 provided with the ninth glue point 39 is respectively connected to the first sub-grid 41 and the third sub-grid 43 adjacent to both sides through the eighth electrical connection line 58. Figure 3 The g form is shown in .

[0054] To prevent the second glue dot 32 from overflowing onto the auxiliary grid 4, the distance d1 between the second glue dot 32 and the auxiliary grids 4 on both sides is not less than 0.1 mm. Figure 2 shown.

[0055] As a preferred case, the straight line 5 where the electrical connection line is located intersects with the glue point 3. The structure can be referred to as Figure 4 As shown in the intersecting glue point 301, and is completely covered by the solder strip 2, as shown in Figure 4 As shown; the intersecting electrical connection lines 501 at this time will not cause additional shading, and the output power of the component can be improved.

[0056] In another case, because the electrical connection line 5 is welded below the welding strip 2, there is a certain risk of welding falling off. The electrical connection line 5 can also be designed to be away from the glue point 3: the straight line where the staggered electrical connection line 502 is located is staggered with the staggered glue point 302, and the horizontal distance d2 between the staggered electrical connection line 502 and the staggered glue point 302 is less than or equal to 1 / 2 of the projection distance d3 of two adjacent glue points 3 (here, the intersecting glue point 301 and the staggered glue point 302) along the extension direction of the auxiliary grid 4. The structure can refer to Figure 4 shown.

[0057] Furthermore, the width W1 of the glue spot 3 is greater than or equal to the width W2 of the auxiliary grid 4, and the length L1 of the glue spot 3 is greater than or equal to the width W3 of the welding strip 2 to ensure the bonding strength. Figure 5 The center distance L2 of the two outermost glue application points does not exceed the distance L3 between the two outermost auxiliary grids, as shown in FIG. Figure 5 shown.

[0058] Preferably, the projection length L4 of the electrical connection line 5 in the direction perpendicular to the auxiliary grid 4 is greater than or equal to the minimum distance between two adjacent auxiliary grids 4, and the projection length L4 is less than or equal to the maximum distance L3 between the two outermost auxiliary grids 4. Figure 6 shown.

[0059] The embodiment of the present invention further provides a method for connecting a solar cell string, using the above-mentioned solar cell string connection structure, after the glue point is applied and before lamination, comprising the following steps:

[0060] Pre-bond the solder strip 2 to the battery cell 1 via the glue point 3;

[0061] Curing glue point 3;

[0062] The connecting body composed of the battery cell 1, the welding strip 2 and the glue point 3 is welded so that the welding strip 2 forms an alloy contact with the auxiliary grid 4. The process can be referred to as follows: Figure 7 shown.

[0063] It can be seen from the above technical scheme that the connection method of the solar cell string provided by the embodiment of the present invention designs an electrical connection line 5 at the auxiliary grid 4, and provides other channels between the auxiliary grids 4 to transmit current to the welding strip 2; when the auxiliary grid 4 and the welding strip 2 cannot effectively contact each other, the current can be transmitted to the auxiliary grid 4 connected thereto through the electrical connection line 5, and then transmitted to the welding strip 2, or directly transmitted to the welding strip 2 by the electrical connection line 5, thereby reducing the risk of poor contact caused by the overflow of the glue point 3 onto the auxiliary grid 4; this scheme does not require a main grid, reduces the silver paste consumption of the battery cell, and reduces the battery cost; after applying the glue and before lamination, the welding strip is directly welded to melt the solder and form a good alloy contact with the battery grid line, and the solder will no longer melt again during lamination, thereby reducing the risk of the glue film penetrating into the gap between the welding strip and the battery.

[0064] Preferably, the curing method includes: light irradiation and heat pressing. After the glue is cured, the soldering strip 2 and the battery cell 1 will form a relatively stable connection strength.

[0065] Specifically, the welding methods include: infrared welding, hot air welding and induction heating, and the welding temperature is 130° C. to 300° C. to form an electrical connection between the auxiliary grid and the welding strip.

[0066] Furthermore, when the glue used can be cured by heat, the curing of the glue can be carried out in the same process as welding, that is, the curing is completed during welding or the curing of the glue is carried out during the preheating stage of welding.

[0067] The present invention is further described below in conjunction with specific embodiments:

[0068] The present application discloses a connection structure and method of a solar cell string, wherein the cell string comprises a plurality of cells connected in series, two adjacent cells are connected by a welding strip, and glue is used to fix the secondary grid and the cell. On the surface of the cell, the cell and the welding strip are pre-bonded together by applying glue at a specified position on the cell and / or the welding strip, such as Figure 1 .

[0069] In order to ensure that the soldering tape can be effectively bonded to the battery cell, the number of glue application points at the corresponding position of a single soldering tape of a single cell is not less than two and does not exceed the number of the battery's secondary grid lines. To ensure the bonding strength, the glue width W1 ≥ the secondary grid width W2, and the glue length L1 ≥ the soldering tape width W3. The center distance L2 of the two outermost glue application points does not exceed the distance L3 between the two outermost secondary grids, such as Figure 5 .

[0070] The glue used can be either a conductive glue or an insulating glue without conductive ability. For conductive glue, because it can lead to current, the glue application position is relative to the position of the secondary grid on the surface of the battery cell, preferably on the secondary grid line. The current on this secondary grid can be directly transmitted to the welding strip through the conductive glue; it can also be between two secondary grids, in which case the glue mainly plays a connecting role. For non-conductive glue, it is preferably between two secondary grids, and in order to prevent overflow to the secondary grid line, the distance from the edge of the glue to the secondary grid is not less than 0.3mm; non-conductive glue can also be applied to the secondary grid line, but this secondary grid needs to be processed as a connecting wire to allow the current on this secondary grid to be normally conducted, such as Figure 2 .

[0071] Since the glue has a certain height, the contact performance between the secondary grid and the soldering strip near the glue is weaker than that in the non-glue area. In addition, the glue has a certain fluidity and may overflow to the adjacent secondary grid line, which will also affect the contact between the adjacent secondary grid and the soldering strip. At this time, other channels are needed to transmit current to the soldering strip. One way is Figure 3 , set a secondary grid electrical connection line to electrically connect the secondary grid near the glue application point with other secondary grids. When the adjacent secondary grid cannot effectively contact the welding, the current can be transmitted to the secondary grid connected to it through the electrical connection line, and then transmitted to the welding strip, or directly transmitted to the welding strip by the electrical connection line. At least one secondary grid near it is connected to at least one other secondary grid line through the secondary grid connection line at least one glue application position. Figure 3 ae is some electrical connection examples between two auxiliary grids in the glue application area relative to the cell: Figure 3 The electrical connection line at a connects two auxiliary grids adjacent to the glue application position; Figure 3 At b, an adjacent auxiliary grid is connected to a non-adjacent auxiliary grid; Figure 3 At c, two adjacent auxiliary grids are connected to two non-adjacent auxiliary grids respectively; Figure 3 Connect two adjacent auxiliary grids to the same non-adjacent auxiliary grid at d; Figure 3 At e, two adjacent sub-grids are connected and two non-adjacent sub-grids are connected. Figure 3 fg is an example in which the glue application area is located on the battery secondary grid relative to the battery cell: Figure 3 Connect the sub-grid where the glue application position is located with an adjacent sub-grid at point f; Figure 3 Connect the sub-grid where the glue application position is located with the two adjacent sub-grids at g.

[0072] like Figure 6 In order to further reduce the risk of poor contact between the welding strip and the auxiliary grid, the adjacent auxiliary grid can be connected to more other auxiliary grids, and the projection line length L4 of the electrical connection line in the direction perpendicular to the auxiliary grid does not exceed the spacing L3 between the two auxiliary grids at the outer edge of the cell. The position of the auxiliary grid electrical connection line is preferably intersected with the glue application position and completely covered by the welding strip. At this time, the electrical connection line will not bring additional shading, which can improve the output power of the component. Because the electrical connection line participates in welding under the welding strip, there is a certain risk of welding falling off. The design of the electrical connection line away from the glue application position can also be adopted, and the distance d2 does not exceed 1 / 2 of the projection distance d3 of the two adjacent glue application positions in the direction parallel to the auxiliary grid.

[0073] After the battery cell and the soldering tape are pre-bonded with glue, the glue is cured by light irradiation, heat pressing, etc. After the glue is cured, the soldering tape and the battery cell will form a relatively stable connection strength.

[0074] After forming a stable connection, the battery cell, the soldering ribbon and the connector of the glue are welded by a welding machine, so that the soldering ribbon and the secondary grid of the battery form an alloy contact, forming an electrical connection between the secondary grid and the soldering ribbon. The welding methods include infrared welding, hot air welding, induction heating, etc. The welding temperature is 130℃~300℃.

[0075] When the glue used can be cured by heat, the curing of the glue can be carried out in the same process as welding, that is, the curing is completed during welding or the curing of the glue is carried out during the preheating stage of welding.

[0076] After welding, the battery cell and the welding ribbon form a stable mechanical connection through glue, and the welding ribbon and the auxiliary grid form an electrical connection through welding, thus forming a battery string with stable electrical and mechanical connections.

[0077] In this solution, after applying glue and before lamination, the solder strip is directly welded to make the solder melt and form a good alloy contact with the battery grid line, and the solder will not melt again during lamination, reducing the risk of the glue film penetrating into the gap between the solder strip and the battery.

[0078] In addition, this solution also provides a battery graphic design for the glue application position. In order to reduce the risk of poor contact caused by glue overflowing onto the secondary grid, a secondary grid electrical connection line is designed on the secondary grid adjacent to the glue application position.

[0079] In summary, the embodiment of the present invention discloses a connection structure and method of a solar cell string, wherein the cell sheet and the welding strip are pre-bonded by glue, and a plurality of glue application positions are arranged in parallel to the welding strip direction, and the number of glue application points at each welding strip of each cell sheet is ≥ 2, and ≤ the number of secondary grid lines on the battery unit; an electrical connection line is arranged on a secondary grid adjacent to at least one glue application point, and the secondary grid is connected to other secondary grids by the connection line, and the length of the connection line is not less than the vertical distance between the two secondary grids, and not greater than the distance between the two outermost secondary grids;

[0080] After the battery cell and the soldering strip are pre-bonded with glue, the glue is cured. After curing, the soldering strip forms a good mechanical connection with the battery cell. The connector is welded. After welding, the soldering strip forms an electrical connection with the secondary grid / electrical connection line of the battery cell to form the final battery string. The curing of the glue can also be carried out simultaneously with the welding, that is, the curing of the glue is completed simultaneously using the welding temperature.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] 1. Reduce the silver paste consumption of battery cells and reduce battery costs;

[0083] 2. Improve the reliability of the connection between the solder ribbon and the battery.

[0084] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A connection structure of a solar cell string, characterized in that: include: A battery cell (1), a welding strip (2), a glue point (3), a secondary grid (4) and an electrical connection line (5), wherein the glue point (3) and the secondary grid (4) are respectively arranged on the surface of the battery cell (1), the welding strip (2) is pre-fixed to the battery cell (1) through the glue point (3), and the welding strip (2) is electrically connected to a plurality of the secondary grids (4), and the electrical connection line (5) is connected to a plurality of the secondary grids (4).

2. The connection structure according to claim 1, characterized in that: The glue dots (3) are electrically conductive glue dots (3), the glue dots (3) are located on the auxiliary grid (4), and the auxiliary grid (4) provided with the glue dots (3) is connected to the electrical connection line (5).

3. The connection structure according to claim 1, characterized in that: At least one of the glue dots (3) is a conductive glue dot (3), the glue dot (3) is located between two adjacent sub-grids (4), and at least one of the sub-grids (4) on both sides of the glue dot (3) is connected to the electrical connection line (5).

4. The connection structure according to claim 1, characterized in that: The glue dots (3) are insulating glue dots (3), the glue dots (3) are located on the auxiliary grid (4), and the auxiliary grid (4) provided with the glue dots (3) is connected to the electrical connection line (5).

5. The connection structure according to claim 1, characterized in that: The glue point (3) is an insulating glue point (3), the glue point (3) is located between two adjacent sub-grids (4), and at least one of the sub-grids (4) on both sides of the glue point (3) is connected to the electrical connection line (5).

6. The connection structure according to claim 3 or 5, characterized in that: The two ends of the electrical connection line (5) are respectively connected to the auxiliary grids (4) on both sides of the glue point (3).

7. The connection structure according to claim 3 or 5, characterized in that: A single one of the auxiliary grids (4) on both sides of the glue point (3) is connected to the adjacent auxiliary grid (4) on the outside of the same side through the electrical connection line (5).

8. The connection structure according to claim 3 or 5, characterized in that: The auxiliary grids (4) on both sides of the glue point (3) are respectively connected to the auxiliary grids (4) adjacent to the outer side of the same side through the electrical connection lines (5).

9. The connection structure according to claim 3 or 5, characterized in that: The auxiliary grids (4) on both sides of the glue point (3) are connected via the electrical connection line (5), and a single one of the auxiliary grids (4) on both sides of the glue point (3) is connected to the adjacent auxiliary grid (4) on the outside of the same side via the electrical connection line (5).

10. The connection structure according to claim 3 or 5, characterized in that: The auxiliary grids (4) on both sides of the glue point (3) are connected via the electrical connection line (5), and the auxiliary grids (4) on both sides of the glue point (3) are respectively connected to the auxiliary grids (4) adjacent to the outer side of the same side via the electrical connection line (5).

11. The connection structure according to claim 2 or 4, characterized in that: The auxiliary grid (4) provided with the glue point (3) is connected to the auxiliary grid (4) adjacent to one side through the electrical connection line (5).

12. The connection structure according to claim 2 or 4, characterized in that: The auxiliary grid (4) provided with the glue point (3) is respectively connected to the auxiliary grids (4) adjacent to each other on both sides through the electrical connection lines (5).

13. The connection structure according to claim 3 or 5, characterized in that: The distance d1 from the glue point (3) to the auxiliary grids (4) on both sides is not less than 0.1 mm.

14. The connection structure according to claim 1, characterized in that: The straight line where the electrical connection line (5) is located intersects with the glue point (3) and is completely covered by the welding strip (2).

15. The connection structure according to claim 1, characterized in that: The straight line on which the electrical connection line (5) is located is staggered from the glue point (3), and the distance d2 between the electrical connection line (5) and the glue point (3) is less than or equal to 1 / 2 of the projection distance d3 of two adjacent glue points (3) along the extension direction of the auxiliary grid (4).

16. The connection structure according to claim 1, characterized in that: The width W1 of the glue dot (3) is greater than or equal to the width W2 of the auxiliary grid (4), and the length L1 of the glue dot (3) is greater than or equal to the width W3 of the welding strip (2).

17. The connection structure according to claim 1, characterized in that: The projection length L4 of the electrical connection line (5) in a direction perpendicular to the auxiliary grid (4) is greater than or equal to the minimum distance between two adjacent auxiliary grids (4), and the projection length L4 is less than or equal to the maximum distance L3 between the two outermost auxiliary grids (4).

18. A method for connecting a solar cell string, characterized in that: The connection structure of the solar cell string according to any one of claims 1 to 17 comprises the following steps after the glue application and before the lamination: Pre-bonding the solder strip (2) to the battery cell (1) via the glue point (3); Curing the glue dots (3); The connecting body formed by the battery cell (1), the welding strip (2) and the glue point (3) is welded so that the welding strip (2) forms alloy contact with the auxiliary grid (4).

19. The connection method according to claim 18, characterized in that: The curing methods include: light irradiation and heat pressing.

20. The connection method according to claim 18, characterized in that: The welding methods include infrared welding, hot air welding and induction heating, and the welding temperature is 130°C to 300°C.

21. The connection method according to claim 18, characterized in that: The curing is completed during the welding, or is performed during the welding preheating stage.

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