Back contact cell string, series welding equipment and manufacturing method thereof, and photovoltaic module

Abstract

The invention relates to the photovoltaic field, and discloses a back contact cell string, a series welding device and a manufacturing method thereof, and a photovoltaic module. The back contact battery string comprises a plurality of battery pieces, a welding rod and a skin film. And the skin membrane comprises closed areas and opening areas which are alternately distributed at intervals. The area where the skin film is attached to the welding rod is a closed area. The photovoltaic module comprises the back contact cell string. The series welding equipment is used for welding the back contact battery string and comprises a rack, a conveying mechanism, a substrate platform and a heating assembly. A plurality of slotted holes are formed in the conveying belt; the skin film is laid on the conveying belt, and corresponding groove holes are formed below the closed area and the hole opening area of the skin film. A plurality of air suction holes corresponding to the groove holes are formed in the base plate platform. The manufacturing method of the back contact battery string adopts the series welding equipment, and comprises the following steps: S1, placing a skin membrane and preheating the skin membrane; s2, placing a welding rod and laying a battery piece; and S3, welding a welding rod.

Description

Technical Field

[0001] The present invention relates to the photovoltaic field, and in particular to a back-contact battery string and a string welding device, a manufacturing method, and a photovoltaic module. Background Art

[0002] At present, the back contact solar cell string welding production equipment is generally divided into: infrared heat welding, film-coated string welding, both of which require the use of a press to position the cell and the welding rod. Among them, the existing infrared heat welding has a more obvious disadvantage, that is, the cell warps severely after welding. Although the film-coated string welding can solve the warping problem, it is easy to fail in the TC thermal cycle test and DH wet heat test of the component.

[0003] For example, the patent "CN 220553452 U" discloses a busbar-free back-contact battery string, photovoltaic module and string-making equipment. The patent provides a busbar-free back-contact battery string, in which the battery cells constituting the battery string only have positive and negative metal grid lines interlaced on the back of the battery cells, and the welding rods are alternately interlaced with the positive and negative metal grid lines in series, and the welding rods are fixed to the back of the battery cells through adhesive films, which simplifies the above-mentioned busbar-free battery cell series connection process. (Referred to as the back contact battery film coating solution).

[0004] Patent "CN220895518U" discloses a battery string preparation device, which further explains how patent "CN220553452 U" performs back contact battery string welding.

[0005] Patent "CN 221262412 U" discloses a press and film composite conveying device and battery string production equipment, which mainly aims to improve the problems existing in the press in the existing technical solution of patent "CN220895518U". The technical solution can solve the problem that the position of the press gripper grabbing the press is always changing due to multiple transfers of the press, and the relative position of the press and the film also changes. The film grabbing component of the string laying gripper needs to pass through the hole opened in the press to grab the film, which causes the string laying gripper to adjust its position before grabbing, thereby causing the grabbing accuracy of the string laying claw to decrease and affecting the grabbing rate.

[0006] Therefore, although the existing string welding technology can better fix the welding rod and the battery cell, it still has the following problems:

[0007] 1. Existing back-contact solar cell string welding equipment requires the use of a press to pre-position the photovoltaic welding rod. The use of a press is likely to increase scratches on the cell surface, resulting in reduced photovoltaic cell string welding efficiency. The presence of the press requires a robot and a conveyor track to grab the press, which makes the overall structure of the equipment more complicated, increasing the equipment cost and significantly increasing the equipment failure rate.

[0008] Second, the existing back contact battery coating scheme uses conventional skin film for packaging. Although it can fix the welding rod and the battery cell well, the skin film also creates a certain gap with the adhesive film of the bonding back plate, which leads to a decrease in the bonding ability between the back of the battery and the back plate, and there is a great hidden danger to the reliability of the component. It is particularly easy to cause the TC thermal cycle test experiment and the DH damp heat test experiment to fail. Summary of the invention

[0009] The purpose of the present invention is to solve the problems of the prior art string welding rods and the problems of component packaging, and to provide a back-contact battery string and its string welding equipment, manufacturing method, and photovoltaic component. The traditional skin membrane is replaced by a skin membrane with holes in specific areas to reduce the problems of battery surface scratches, low string welding efficiency, and complex equipment structure caused by the use of pressing blocks. At the same time, the perforated skin membrane can also enhance the adhesion inside the component and improve the failure problem of the component TC thermal cycle test experiment and DH wet heat test experiment.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] The present invention discloses a back contact battery string, which includes a plurality of battery cells, welding rods and skin membranes. The welding rods are attached to the main grid regions of two adjacent battery cells. The skin membrane is arranged below the welding rods and is used to fix the welding rods on the battery cells. The skin membrane includes closed areas and open areas that are alternately distributed at intervals; the area where the skin membrane and the welding rods are attached is the closed area.

[0012] Furthermore, the opening area is provided with a plurality of small pores or large round holes or slots or other irregular gaps.

[0013] Furthermore, the skin membrane is an EVA film that has been irradiated and has a gram weight between 95 g / ㎡ and 105 g / ㎡.

[0014] The present invention also discloses a back-contact cell photovoltaic module, comprising a photovoltaic front panel, a first adhesive film, a cell string, a second adhesive film, and a photovoltaic back panel laminated in sequence; the cell string is the above-mentioned back-contact cell string; the photovoltaic front panel is bonded to the front side of the cell string through the first adhesive film, and the photovoltaic back panel is bonded to the skin membrane and the back side of the cell string respectively through the second adhesive film penetrating through the opening area of ​​the skin membrane.

[0015] Furthermore, the photovoltaic front panel is glass or ETFE, the first adhesive film and the second adhesive film are one of EVA, POE, and EPE, and the photovoltaic back panel is glass or KPF.

[0016] The present invention also discloses a string welding device for welding the above-mentioned back contact battery string, which comprises a frame, a conveying mechanism, a substrate platform, and a heating component.

[0017] The conveying mechanism includes a conveying wheel and a conveyor belt; the conveyor belt includes an upper conveyor belt and a lower conveyor belt; the conveying mechanism is arranged on a frame, the upper conveyor belt is located above the frame operating table, and the lower conveyor belt is located below the frame operating table; a plurality of slots are arranged on the conveyor belt; a skin membrane is laid on the conveyor belt, and the corresponding slots are arranged below the closed area and the open area of ​​the skin membrane.

[0018] The substrate platform includes a plurality of substrates, which are arranged on the conveying mechanism and located inside the conveyor belt; each substrate platform is provided with a plurality of air suction holes, which correspond to the slot holes; and the heating component is arranged inside the substrate.

[0019] Furthermore, the substrate on which the upper conveyor belt is arranged is a first substrate, and the substrate on which the lower conveyor belt is arranged is a second substrate. The suction holes of the first substrate are arranged in areas corresponding to the closed area and the open area for laying the skin membrane, and the suction holes of the second substrate are arranged in areas corresponding to the closed area for laying the skin membrane, and the suction holes of each substrate are arranged in a separate circuit.

[0020] Furthermore, the heating component includes a heater and a temperature sensor.

[0021] Furthermore, a welding rod conveying and cutting mechanism is arranged above the upper conveyor belt, a skin membrane conveying and cutting mechanism is arranged below the lower conveyor belt, and a cooling device is also arranged at the end of the upper conveyor belt.

[0022] The present invention also discloses a method for manufacturing a back-contact battery string, which uses the above-mentioned string welding equipment and includes the following steps:

[0023] S1. Placing the skin membrane and preheating: placing the segmented skin membrane on a conveyor belt, and adsorbing the skin membrane on the conveyor belt through a substrate platform and preheating and shrinking it, wherein the preheating temperature is 80°C-100°C;

[0024] S2. Place welding rods and lay out cells: The skin membrane is conveyed to the operating table by a conveyor belt, and the segmented welding rods are placed on the skin membrane, and several cells are placed on the welding rods. The cells are adsorbed and fixed on the conveyor belt through the substrate platform, and the main grid area on the back of the cell fits with the welding rods;

[0025] S3, welding electrode: heat the skin membrane, and bond and fix the laid welding rod to the back of the battery through the skin membrane.

[0026] Furthermore, the method further comprises step S4, cooling and removing materials: cooling the fixed product and removing the welded battery string.

[0027] The benefits of the present invention are:

[0028] The present invention replaces the traditional skin membrane with a skin membrane with holes in specific areas, fixes it through adsorption, eliminates the positioning of the pressing block, and reduces the problems of battery surface scratches, low string welding efficiency, complex equipment structure, etc. caused by the use of pressing blocks. At the same time, the perforated skin membrane can also enhance the adhesion inside the component and improve the failure problem of the component TC thermal cycle test experiment and DH wet heat test experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 It is a structural schematic diagram of a battery string in Example 1.

[0031] Figure 2 yes Figure 1 A partial enlarged view of point A in the middle.

[0032] Figure 3 It is a schematic diagram of the local planar structure of the skin membrane of the present invention.

[0033] Figure 4 It is a schematic diagram of the planar structure in which the welding rod is set on the skin membrane.

[0034] Figure 5 It is a structural schematic diagram of the welding equipment of Example 3.

[0035] Figure 6 It is a schematic diagram of the local planar structure of the second substrate in the welding equipment.

[0036] Figure 7 It is a schematic diagram of the partial planar structure of the conveyor belt in the welding equipment.

[0037] Figure 8 It is a positional relationship diagram between the second substrate and the conveyor belt in the welding equipment.

[0038] Fig. 9 It is a positional relationship diagram among the second substrate, conveyor belt, and skin membrane in the welding equipment.

[0039] Fig.10 It is a schematic diagram of the local planar structure of the first substrate in the welding equipment.

[0040] Fig.11 It is a positional relationship diagram among the first substrate, the conveyor belt, and the skin membrane in the welding equipment.

[0041] Main component symbols:

[0042] 1. Battery cells;

[0043] 2. Welding rod;

[0044] 3. Skin membrane, 31. Closed area, 32. Open area;

[0045] 4. Skin membrane conveying and cutting mechanism;

[0046] 5. conveyor belt, 51. upper conveyor belt, 52. lower conveyor belt, 53. slot;

[0047] 6. Substrate platform, 61. First substrate, 62. Second substrate, 63. Air suction hole. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the specification. Obviously, the described embodiments are 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.

[0049] In the present invention, unless otherwise specified, directional words such as "upper, lower, left, right" are generally understood in conjunction with the directions shown in the drawings and actual applications.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0052] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. Among them, the terms "optional" and "optional" all mean that they may be included or not included (or may be present or not).

[0053] like Figures 1 to 4 As shown, the present invention discloses a back-contact battery string, which includes a plurality of battery cells 1, welding rods 2 and skin membranes 3. The welding rods 2 are in contact with the main grid regions of two adjacent battery cells 1. The skin membrane 3 is arranged below the welding rods 2, and is used to fix the welding rods 2 on the battery cells 1. The skin membrane 3 includes closed areas 31 and open areas 32 that are alternately distributed. During string welding, the closed area 31 serves as an adsorption and fixing area for the skin membrane 3, and is used to adsorb and fix the skin membrane 3 on a conveyor belt. The open area 32 serves as an adsorption and fixing area for the battery cell 1, and the battery cell 1 can be adsorbed and fixed on a conveyor belt through the open area 32.

[0054] In this embodiment, a skin membrane 3 with holes opened in specific areas replaces the traditional skin membrane, and fixes the skin membrane 3 and the battery cell 1 by adsorption, eliminates the positioning of the pressing block, and reduces the problems of battery surface scratches, low string welding efficiency, and complex equipment structure caused by the use of the pressing block.

[0055] The area where the skin film 3 and the welding rod 2 are attached is a closed area 31. This can prevent the adhesive film from melting and penetrating between the photovoltaic welding rod 2 and the back contact cell.

[0056] Among them, a number of small pores or large round holes or slots 53 or other irregular gaps are arranged on the opening area 32. The main purpose is to allow the battery cell 1 to be adsorbed on the pore film and accurately aligned with the photovoltaic welding rod, and to use the heating system of the substrate platform 6 to bond the pore film to the back of the battery to fix the photovoltaic welding rod.

[0057] Specifically, the skin film 3 is an EVA film with a gram weight of 95 g / ㎡ to 105 g / ㎡ after irradiation treatment.

[0058] Embodiment 2:

[0059] The present invention also discloses a back-contact cell photovoltaic module, comprising a photovoltaic front plate, a first adhesive film, a cell string, a second adhesive film, and a photovoltaic back plate laminated in sequence. The cell string is the back-contact cell string of Example 1. The photovoltaic front plate is bonded to the front side of the cell string through the first adhesive film, and the photovoltaic back plate is bonded to the skin film 3 and the back side of the cell string respectively through the second adhesive film penetrating through the opening area 32 of the skin film 3.

[0060] When conventional skin membrane 3 battery strings are laminated, in order to prevent the adhesive film from melting and seeping into the photovoltaic welding rod 2 and the back contact battery, the skin membrane 3 will be made of an isolation adhesive film material, so the relationship between them is: the backplane is bonded to the adhesive film, the adhesive film is bonded to the skin membrane 3, and the skin membrane 3 is bonded to the back of the battery. Because there is a layer of skin membrane 3 in between, it is easy to cause the adhesion between the backplane and the back of the battery to decrease. In this embodiment, when laminating, the adhesive film can penetrate the opening area 32 of the skin membrane 3 to form a stronger bond with the back of the battery cell 1, thereby improving the adhesion between the backplane and the battery cell 1, and further improving the reliability of the photovoltaic module. Improve the problem of failure of the component TC thermal cycle test experiment and DH wet heat test experiment.

[0061] Among them, the photovoltaic front panel is glass or ETFE, the first adhesive film and the second adhesive film are one of EVA, POE, and EPE, and the photovoltaic back panel is glass or KPF.

[0062] Embodiment three:

[0063] like Figures 1 to 11 As shown, the present invention also discloses a string welding device for welding the above-mentioned back contact battery string, which includes a frame, a conveying mechanism, a substrate platform 6, a heating component, a skin film 3 conveying and cutting mechanism 4, a welding rod conveying and cutting mechanism, and a cooling device. Among them, the conveying mechanism is fixed on the frame and is used to convey the skin film 3, the welding rod and the battery cell 1. The substrate platform 6 is arranged inside the conveying mechanism, and is used to adsorb and fix the skin film 3 and the battery cell 1. The heating component is arranged on the substrate platform 6, and is used to preheat the skin film 3 and subsequently heat the skin film 3 to weld the welding rod 2 to the battery cell 1. The rolled skin film 3 is arranged on the skin film 3 conveying and cutting mechanism 4, and the skin film 3 conveying and cutting mechanism 4 is arranged below the conveying mechanism. After the skin film 3 is cut to a set length, it is adsorbed and fixed on the conveying mechanism by the substrate platform 6, and preheated. The welding rod conveying and cutting mechanism is arranged above the conveying mechanism, and the welding rod 2 is placed on the skin film 3 after being cut to a set length by the welding rod conveying and cutting mechanism. The cooling device is arranged at the rear end of the conveying mechanism, and is used to cool the battery string after welding, so as to facilitate material collection.

[0064] Specifically, Figure 5 As shown, the conveying mechanism includes a conveying wheel and a conveyor belt 5. The conveyor belt 5 includes an upper conveyor belt 51 and a lower conveyor belt 52. The upper conveyor belt 51 is located above the rack operating table, and the lower conveyor belt 52 is located below the rack operating table. Figure 7 As shown, the conveyor belt 5 is provided with a plurality of slots 53. Fig. 9 As shown, the skin membrane 3 is laid on the conveyor belt, and corresponding slots 53 are provided below the closed area 31 and the open area 32 of the skin membrane 3 .

[0065] The substrate platform 6 includes a plurality of substrates, which are arranged on the conveying mechanism and located on the inner side of the conveyor belt. Each substrate platform 6 is provided with a plurality of suction holes 63.

[0066] Specifically, the substrate disposed on the upper conveyor belt 51 is the first substrate 61, and the substrate disposed on the lower conveyor belt 52 is the second substrate 62. Figures 6 to 9 As shown, the suction holes 63 of the first substrate 61 are arranged in the area corresponding to the closed area 31 and the opening area 32 where the skin film 3 is laid, and are used to absorb and fix the skin film 3 and the battery cell 1. Fig.10 , 11 As shown, the suction holes 63 of the second substrate 62 are arranged in an area corresponding to the closed area 31 where the skin membrane 3 is laid, so as to absorb and fix the skin membrane 3 .

[0067] The suction hole 63 of each substrate is set as a separate circuit to ensure airtightness during suction.

[0068] Specifically, the heating assembly includes a heater and a temperature sensor. The heater and the temperature sensor form a thermocouple heating platform, and the temperature can be set through the control panel of the string welding equipment.

[0069] This embodiment also discloses a manufacturing method using the above-mentioned string welding device, which comprises the following steps:

[0070] S1. Placing the skin membrane 3 and preheating: placing the segmented skin membrane 3 on the conveyor belt 5, and adsorbing the skin membrane 3 on the conveyor belt through the substrate platform 6 and preheating it, wherein the preheating temperature is 80°C-100°C. Preheating the skin membrane 3 first can make the surface of the skin membrane 3 have a certain degree of adhesion, and after laying the photovoltaic welding rod, the photovoltaic welding rod will not run on the skin membrane 3, and the skin membrane 3 that has shrunk after preheating will not shrink and deform further.

[0071] S2, placing welding rod 2 and laying out battery cell 1: the skin film 3 is conveyed to the operating table along the conveyor belt 5, the segmented welding rod 2 is placed on the skin film 3, and a number of battery cells 1 are placed on the welding rod 2, and the battery cells 1 are adsorbed and fixed on the conveyor belt 5 through the substrate platform 6, wherein the main grid area on the back of the battery cell 1 is in contact with the welding rod 2;

[0072] S3, welding electrode 2: heating the skin membrane 3, and bonding and fixing the laid electrode 2 to the back of the battery through the skin membrane 3.

[0073] S4, cooling and material removal: cool down the fixed product and remove the welded battery string.

[0074] In the prior art, if the front side of the back-contact solar cell is welded with the front side facing upward, the laying sequence is the same as that of the present embodiment, but two problems will occur: First, if a pressing block is not used to press the cell 1, the cell 1 will move and be misplaced as the conveyor belt moves; Second, the skin membrane 3 will shrink during the welding process, causing the photovoltaic welding rod 2 to be misplaced with the main grid position on the back side of the cell. If the front side of the back-contact solar cell is welded with the front side facing downward, the cell 1 is laid first, and then the photovoltaic welding rod 2 is laid. At this time, the photovoltaic welding rod 2 needs to be pressed by a pressing block to prevent it from moving, and the pressing block also needs to be introduced. However, the present embodiment pre-sets the suction structure of the skin membrane 3, the substrate platform 6, and the conveyor belt, so that the skin membrane 3 can be adsorbed and the photovoltaic welding rod 2 can be fixed on the skin membrane 3. Furthermore, the cell 1 can be adsorbed, and the substrate platform 6 is heated for string welding, thereby achieving the goal of not using a string welding pressing block, which can reduce the use of equipment manipulators and the arrangement of the pressing block conveying platform, and greatly reduce equipment costs.

[0075] In summary, the present invention replaces the traditional skin membrane with a skin membrane with holes in a specific area, fixes by adsorption, eliminates the positioning of the pressing block, reduces the problems caused by the use of the pressing block, and improves product quality and production efficiency. At the same time, the perforated skin membrane can also improve the adhesion inside the component, and improve the failure of the component TC thermal cycle test experiment and DH wet heat test experiment.

[0076] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A back contact battery string, characterized in that: It includes several battery cells, welding rods and skin membranes; the welding rods are attached to the main grid areas of two adjacent battery cells; the skin membrane is arranged under the welding rods to fix the welding rods on the battery cells; the skin membrane includes closed areas and open areas that are alternately distributed; the area where the skin membrane and the welding rods are attached is the closed area.

2. The back contact battery string according to claim 1, characterized in that: The opening area is provided with a plurality of small pores or large round holes or slots or other irregular gaps.

3. The back contact battery string according to claim 1, characterized in that: The skin membrane is an irradiated EVA film with a gram weight between 95g / ㎡ and 105g / ㎡.

4. A back-contact cell photovoltaic module, comprising a photovoltaic front sheet, a first adhesive film, a cell string, a second adhesive film, and a photovoltaic back sheet laminated in sequence; characterized in that: The battery string is a back-contact battery string as described in any one of claims 1 to 3; the photovoltaic front panel is bonded to the front side of the battery string through a first adhesive film, and the photovoltaic back panel is bonded to the skin membrane and the back side of the battery string respectively through a second adhesive film penetrating through the opening area of ​​the skin membrane.

5. The back contact cell photovoltaic module according to claim 4, characterized in that: The photovoltaic front plate is glass or ETFE, the first adhesive film and the second adhesive film are one of EVA, POE, and EPE, and the photovoltaic back plate is glass or KPF.

6. A string welding device for welding the back contact battery string according to any one of claims 1 to 3, characterized in that: It includes a frame, a conveying mechanism, a substrate platform, and a heating component; The conveying mechanism includes a conveying wheel and a conveying belt; the conveying belt includes an upper conveying belt and a lower conveying belt; the conveying mechanism is arranged on a frame, the upper conveying belt is located above the frame operating table, and the lower conveying belt is located below the frame operating table; a plurality of slots are arranged on the conveying belt; the skin membrane is laid on the conveying belt, and the corresponding slots are arranged below the closed area and the open area of ​​the skin membrane; The substrate platform comprises a plurality of substrates, which are arranged on the conveying mechanism and located on the inner side of the conveying belt; each substrate platform is provided with a plurality of air suction holes, which correspond to the slot holes, and the heating component is arranged inside the substrate.

7. The string welding equipment according to claim 6, characterized in that: The substrate on which the upper conveyor belt is arranged is the first substrate, and the substrate on which the lower conveyor belt is arranged is the second substrate. The suction holes of the first substrate are arranged in areas corresponding to the closed area and the open area where the skin membrane is laid, and the suction holes of the second substrate are arranged in areas corresponding to the closed area where the skin membrane is laid, and the suction holes of each substrate are arranged in a separate circuit.

8. The string soldering equipment according to claim 6, characterized in that: The heating assembly includes a heater and a temperature sensor.

9. The string welding equipment according to claim 6, characterized in that: A welding rod conveying and cutting mechanism is arranged above the upper conveyor belt, a skin membrane conveying and cutting mechanism is arranged below the lower conveyor belt, and a cooling device is also arranged at the end of the upper conveyor belt.

10. A method for manufacturing a back contact battery string, characterized in that: The string welding device according to claim 6 comprises the following steps: S1. Placing the skin membrane and preheating: placing the segmented skin membrane on a conveyor belt, and adsorbing the skin membrane on the conveyor belt through a substrate platform and preheating and shrinking it, wherein the preheating temperature is 80°C-100°C; S2. Place welding rods and lay out cells: The skin membrane is conveyed to the operating table by a conveyor belt, and the segmented welding rods are placed on the skin membrane, and several cells are placed on the welding rods. The cells are adsorbed and fixed on the conveyor belt through the substrate platform, and the main grid area on the back of the cell fits with the welding rods; S3, welding electrode: heat the skin membrane, and bond and fix the laid welding rod to the back of the battery through the skin membrane.

11. The method for manufacturing a back contact battery string according to claim 10, characterized in that: The method also includes step S4, cooling and removing materials: cooling the fixed product and removing the welded battery string.

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