阅读说明：本技术 一种背接触电池组件生产方法及系统 (Production method and system of back contact battery assembly ) 是由 蒋仙 陈军 李华 刘继宇 于 2020-05-27 设计创作，主要内容包括：本发明提供了一种背接触电池组件生产方法及系统,涉及太阳能光伏技术领域。生产方法包括：采用粘合剂,将焊带粘接在一个背接触太阳电池的第一主栅,以及相邻背接触太阳电池的第二主栅上,得到电池串前体；所述第一主栅和所述第二主栅的极性相反；对包括有所述电池串前体的层叠件进行层压,得到背接触电池组件；在层压过程中,所述焊带与所述第一主栅、所述第二主栅导电互连。在层压过程中焊带与第一主栅和第二主栅才进行导电互连,电池串前体的两侧的封装胶膜等材料具有较好的柔韧性,可以充分吸收导电互连过程中的热应力,同时,电池串前体两侧的封装胶膜、封装材料,对电池串前体可以进行适当的位置限定,减小了热应力引起的翘曲。(The invention provides a method and a system for producing a back contact battery pack, and relates to the technical field of solar photovoltaics. The production method comprises the following steps: bonding the solder strips on a first main grid of one back contact solar cell and a second main grid of an adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid; laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination. The solder strip, the first main grid and the second main grid are conductively interconnected in the laminating process, the packaging films and other materials on the two sides of the battery string precursor have good flexibility and can fully absorb the thermal stress in the conductive interconnection process, meanwhile, the packaging films and the packaging materials on the two sides of the battery string precursor can limit the position of the battery string precursor appropriately, and the warping caused by the thermal stress is reduced.)

1. A method of producing a back contact battery assembly, the method comprising:

bonding the solder strips on a first main grid of one back contact solar cell and a second main grid of an adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid;

laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination.

2. The method of producing a back contact battery assembly of claim 1, wherein the adhesive comprises: adhesive tape and/or thermosetting type adhesive.

3. The method for producing a back contact battery pack according to claim 2, wherein the thermosetting adhesive is selected from the group consisting of: at least one of acrylic resin, rubber resin, silicone resin, epoxy resin, polyvinyl ether, polyvinyl butyral, ethylene-vinyl acetate, polymethyl methacrylate, methyl methacrylate copolymer, methacrylic acid copolymer, and acrylic acid copolymer;

the adhesive tape comprises a base material and glue arranged on the surface of the base material; the material of the substrate is selected from: polyethylene terephthalate and/or polyimide; the glue is at least one selected from silica gel glue, rubber glue and acrylic glue.

4. The method for producing a back contact cell assembly according to claim 2 or 3, wherein, in the case where the adhesive is a thermosetting adhesive, before the step of laminating the stack including the cell string precursor, further comprising:

curing the cell string precursor; the curing temperature is less than or equal to 150 ℃, the curing time is less than or equal to 3 minutes, and the heating speed in the curing process is less than or equal to 10 ℃/s.

5. The method for manufacturing a back contact cell assembly according to claim 1, wherein the step of adhering the solder ribbon to the first main grid of one back contact solar cell and the second main grid of an adjacent back contact solar cell by using an adhesive to obtain the cell string precursor comprises:

disposing the adhesive on each of the bonding points of the first main grid of one back-contact solar cell and each of the bonding points of the second main grid of an adjacent back-contact solar cell;

placing the solder strips on a first main grid of a back contact solar cell provided with the adhesive and a second main grid of an adjacent back contact solar cell;

and applying force to the surface of the solder strip away from the first main grid, so that the solder strip is bonded to each bonding point of the first main grid of one back contact solar cell and each bonding point of the second main grid of the adjacent back contact solar cell through the adhesive.

6. The method for producing a back contact battery pack according to claim 5, wherein the number of the adhesion points on each of the first main grids is 2 to 10; the number of the bonding points on each second main grid is 2-10;

the size of the adhesive on each of the bonding points in a direction parallel to the first main grid or the second main grid is: 0.5-5 mm.

7. The method for producing a back contact battery pack according to claim 1, wherein the first main grid and/or the second main grid is composed of a pad and a thin grid line connecting adjacent pads;

in the cell string precursor, the adhesive is located within the projection of the fine grid line;

during lamination, the solder strips are conductively interconnected with respective pads of the first main gate and respective pads of the second main gate.

8. The method of claim 7, wherein the step of using an adhesive to bond the solder strip to the first main grid of one back-contact solar cell and the second main grid of an adjacent back-contact solar cell is preceded by the step of using an adhesive to bond the solder strip to the first main grid of the one back-contact solar cell and the second main grid of the adjacent back-contact solar cell, further comprising:

applying solder paste on each pad of the first main gate;

and/or applying solder paste on each pad of the second main grid; the melting point of the soldering paste is less than or equal to 150 ℃.

9. The method for producing a back contact battery pack according to claim 1 or 2, wherein the solder ribbon is composed of a base and a low melting point conductive coating coated on the surface of the base; the low-melting point conductive coating is made of a material selected from the group consisting of: low melting point metals and/or low melting point alloys.

10. The method for producing a back contact battery assembly according to claim 9, wherein the material of the low melting point conductive coating is selected from the group consisting of: at least one of silver element, bismuth element, cadmium element, gallium element, indium element, lead element, tin element, titanium element and zinc element.

11. A back contact battery assembly production system, comprising:

the bonding mechanism is used for bonding the welding strips on the first main grid of one back contact solar cell and the second main grid of the adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid;

a lamination mechanism for laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination.

12. The production system of claim 11, wherein the bonding mechanism comprises: the welding device comprises a gluing part, a welding strip placing part and a pressing part;

the gluing part is used for arranging the adhesive on each gluing point of the first main grid of one back contact solar cell and each gluing point of the second main grid of the adjacent back contact solar cell;

the solder strip placing part is used for placing the solder strips on the first main grid of the back contact solar cell provided with the adhesive and the second main grid of the adjacent back contact solar cell;

and the pressing part is used for applying acting force on the surface of the welding strip away from the first main grid, so that the welding strip is adhered to each adhering point of the first main grid of one back contact solar cell and each adhering point of the second main grid of the adjacent back contact solar cell through the adhesive.

13. The production system of claim 12, wherein the location of the force exerted by the nip on the bonding tape is offset from the location of the bond.

14. The production system of claim 12 or 13, wherein the stitching is a pogo pin.

15. The production system according to claim 11, further comprising, in the case where the binder is a thermosetting adhesive:

a curing mechanism for curing the cell string precursor; the curing temperature is less than or equal to 150 ℃, the curing time is less than or equal to 3 minutes, and the heating speed in the curing process is less than or equal to 10 ℃/s.

Technical Field

The invention relates to the technical field of solar photovoltaics, in particular to a method and a system for producing a back contact battery assembly.

Background

The back contact solar cell has the advantages that the front side of the back contact solar cell is not provided with the main grid line, the positive electrode and the negative electrode are arranged on the back side of the cell, shading is reduced, short-circuit current of the cell is effectively increased, energy conversion efficiency is improved, the back contact solar cell is more attractive, and further the application prospect is wide.

Currently, in order to reduce the cost, solder strips are mainly used to conductively interconnect the back contact solar cells.

The inventor discovers in the process of researching the prior art as follows: because welding only occurs on the backlight surface of the battery, the warping caused by welding thermal stress is serious, and the assembly fragments and hidden cracks are serious.

Disclosure of Invention

The invention provides a method and a system for producing a back contact battery pack, and aims to solve the problems of serious fragments and hidden cracks caused by welding conductive interconnection in the back contact battery pack.

In a first aspect of the present invention, there is provided a method of producing a back contact battery assembly, the method comprising:

bonding the solder strips on a first main grid of one back contact solar cell and a second main grid of an adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid;

laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination.

In the embodiment of the invention, the welding strips are adhered to the first main grid of one back contact solar cell and the second main grid of the adjacent back contact solar cell by using an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid; and laminating the laminated body comprising the cell string precursor, wherein in the laminating process, the welding strips are conductively interconnected with the first main grid and the second main grid to obtain the back contact cell assembly. In the embodiment of the invention, the welding strips are not welded on the first main grid and the second main grid before lamination, but are bonded before lamination, so that no thermal stress is generated in the bonding process, the welding strips, the first main grid and the second main grid are conductively interconnected in the lamination process, and packaging adhesive films and other materials on two sides of the cell string precursor in the lamination process have good flexibility, so that the thermal stress in the conductive interconnection process can be fully absorbed, and the warping is reduced; meanwhile, in the laminating process, the packaging adhesive films and the packaging materials on the two sides of the battery string precursor can limit the position of the battery string precursor properly, and the warping caused by thermal stress can be reduced properly. Meanwhile, welding of welding strips before lamination is reduced, welding cost is saved, and production cost is reduced.

Optionally, the adhesive comprises: adhesive tape and/or thermosetting type adhesive.

Optionally, the material of the thermosetting adhesive is selected from: at least one of acrylic resin, rubber resin, silicone resin, epoxy resin, polyvinyl ether, polyvinyl butyral, ethylene-vinyl acetate, polymethyl methacrylate, methyl methacrylate copolymer, methacrylic acid copolymer, and acrylic acid copolymer;

the adhesive tape comprises a base material and glue arranged on the surface of the base material; the material of the substrate is selected from: polyethylene terephthalate and/or polyimide; the glue is at least one selected from silica gel glue, rubber glue and acrylic glue.

Optionally, in a case where the adhesive is a thermosetting adhesive, before the step of laminating the stack including the battery string precursor, the method further includes:

curing the cell string precursor; the curing temperature is less than or equal to 150 ℃, the curing time is less than or equal to 3 minutes, and the heating speed in the curing process is less than or equal to 10 ℃/s.

Optionally, the step of adhering the solder strip to the first main grid of one back-contact solar cell and the second main grid of an adjacent back-contact solar cell by using an adhesive to obtain the cell string precursor includes:

disposing the adhesive on each of the bonding points of the first main grid of one back-contact solar cell and each of the bonding points of the second main grid of an adjacent back-contact solar cell;

placing the solder strips on a first main grid of a back contact solar cell provided with the adhesive and a second main grid of an adjacent back contact solar cell;

and applying force to the surface of the solder strip away from the first main grid, so that the solder strip is bonded to each bonding point of the first main grid of one back contact solar cell and each bonding point of the second main grid of the adjacent back contact solar cell through the adhesive.

Optionally, the number of the bonding points on each first main grid is 2-10; the number of the bonding points on each second main grid is 2-10;

the size of the adhesive on each of the bonding points in a direction parallel to the first main grid or the second main grid is: 0.5-5 mm.

Optionally, the first main gate and/or the second main gate are/is composed of a pad and a thin gate line connecting adjacent pads;

in the cell string precursor, the adhesive is located within the projection of the fine grid line;

during lamination, the solder strips are conductively interconnected with respective pads of the first main gate and respective pads of the second main gate.

Optionally, before the step of adhering the solder strip to the first main grid of one back-contact solar cell and the second main grid of an adjacent back-contact solar cell by using an adhesive, the method further includes:

applying solder paste on each pad of the first main gate;

and/or applying solder paste on each pad of the second main grid; the melting point of the soldering paste is less than or equal to 150 ℃.

Optionally, the solder strip consists of a substrate and a low-melting-point conductive coating coated on the surface of the substrate; the low-melting point conductive coating is made of a material selected from the group consisting of: low melting point metals and/or low melting point alloys.

Optionally, the material of the low melting point conductive coating is selected from: at least one of silver element, bismuth element, cadmium element, gallium element, indium element, lead element, tin element, titanium element and zinc element.

In a second aspect of the present invention, there is provided a back contact battery assembly production system comprising:

the bonding mechanism is used for bonding the welding strips on the first main grid of one back contact solar cell and the second main grid of the adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid;

a lamination mechanism for laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination.

Optionally, the bonding mechanism includes: the welding device comprises a gluing part, a welding strip placing part and a pressing part;

the gluing part is used for arranging the adhesive on each gluing point of the first main grid of one back contact solar cell and each gluing point of the second main grid of the adjacent back contact solar cell;

the solder strip placing part is used for placing the solder strips on the first main grid of the back contact solar cell provided with the adhesive and the second main grid of the adjacent back contact solar cell;

and the pressing part is used for applying acting force on the surface of the welding strip away from the first main grid, so that the welding strip is adhered to each adhering point of the first main grid of one back contact solar cell and each adhering point of the second main grid of the adjacent back contact solar cell through the adhesive.

Optionally, a position of the pressing portion, which applies an acting force on the solder strip, is staggered from a position of the adhesive point.

Optionally, the pressing part is a spring pressing pin.

Optionally, in the case that the adhesive is a thermosetting adhesive, the production system further includes:

a curing mechanism for curing the cell string precursor; the curing temperature is less than or equal to 150 ℃, the curing time is less than or equal to 3 minutes, and the heating speed in the curing process is less than or equal to 10 ℃/s.

The back contact battery pack production system and the back contact battery pack production method can achieve the same or similar beneficial effects, and are not repeated herein to avoid repetition.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 shows a flow chart of the steps of a method of producing a back contact battery assembly in an embodiment of the invention;

fig. 2 shows a schematic structural diagram of a back contact solar cell in an embodiment of the invention;

fig. 3 shows a schematic structural diagram of a cell string precursor in an embodiment of the invention;

fig. 4 is a schematic view showing a partial structure of a system for producing a back contact battery pack according to an embodiment of the present invention.

Description of the figure numbering:

11-solder strip, 2-back contact solar cell, 21-first main grid, 22-second main grid, 211-solder pad, 212-thin grid line, L1-scribing line, 3-bonding mechanism, 31-gluing part, 32-pressing part, 4-curing mechanism and 5-transmission mechanism.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a flow chart illustrating steps of a method for producing a back contact battery assembly in an embodiment of the present invention. The production method of the back contact battery component comprises the following steps:

step S1, bonding the solder strips on the first main grid of one back contact solar cell and the second main grid of the adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the first main gate and the second main gate have opposite polarities.

In the embodiment of the invention, the backlight surface of each back contact solar cell is parallel and is alternately provided with the first main grid and the second main grid, and the polarities of the first main grid and the second main grid are opposite. For example, if the first main grid is a positive main grid, the second main grid is a negative main grid.

For example, referring to fig. 2, fig. 2 shows a schematic structural diagram of a back contact solar cell in an embodiment of the present invention. Fig. 2 may be a bottom view of the back contact solar cell, mainly showing a backlight surface of the back contact solar cell. The back contact solar cell is provided with a scribing line L1, and 2 half cells are obtained after being divided along the scribing line L1. In fig. 2, the first main gate 21 and the second main gate 22 are alternately arranged in parallel in the half on the left side of the scribe line L1, and the polarities of the first main gate 21 and the second main gate 22 are opposite.

The number of the first main grids and the second main grids of the backlight surface of each back contact solar cell is equal, and the sum of the number of the first main grids and the number of the second main grids of the backlight surface of each back contact solar cell can be 10-30. In the embodiment of the present invention, this is not particularly limited.

It should be noted that the back contact solar cell forming the back contact cell module may be a whole cell, or may be a divided cell obtained by dividing the whole cell, and this is not particularly limited in the embodiment of the present invention. If the whole battery is sliced, the size of each sliced battery is approximately the same. By dividing the whole cell into pieces, the area of the divided cell is smaller, and the warping degree of the cell string precursor after lamination can be further reduced. However, when the whole battery is divided into pieces, there are many cutting damages, which may adversely affect the battery performance, and therefore, it is necessary to determine whether or not the whole battery is divided into pieces or divided into several pieces after a comprehensive balance is made.

The adhesive has adhesiveness, and the solder strips are adhered to the first main grid of one back-contact solar cell and the second main grid of the adjacent back-contact solar cell by using the adhesive to obtain the cell string precursor. The first main gate and the second main gate have opposite polarities. For example, the solder strips are bonded to the positive main grid of one back-contact solar cell and the negative main grid of an adjacent back-contact solar cell using an adhesive to form a cell string precursor. In the cell string precursor, the solder strip and the first main grid of the back contact solar cell and the second main grid of the adjacent back contact solar cell are not yet formed with conductive interconnection, and have no thermal stress and no warpage.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a battery string precursor in an embodiment of the present invention. Fig. 3 may be a bottom view of the battery string precursor. In fig. 3, a solder strip 1 is bonded to a first main grid of one back contact solar cell 2 and a second main grid of an adjacent back contact solar cell 2, the polarities of the first main grid and the second main grid being opposite.

Whether or not the above adhesive is conductive is not particularly limited, and in the case where the adhesive is not conductive, the production cost can be reduced.

It should be noted that the adhesive may be provided only on the first main grid of the back-contact solar cell and the second main grid of the adjacent back-contact solar cell, or the adhesive may be provided only on one surface of the solder ribbon. Or the adhesive is disposed on the first main grid of the back contact solar cell, the second main grid of the adjacent back contact solar cell, and one surface of the solder strip, which are not particularly limited. The adhesive may be automatically set by an adhesive applying mechanism, which is not particularly limited in the embodiment of the present invention.

Optionally, the width of the solder strip may be 0.3-1.0 mm, and the cross-sectional shape of the solder strip may be rectangular, triangular or circular. In the embodiment of the present invention, this is not particularly limited.

Step S2, laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination.

The light facing surface of the battery string precursor can be sequentially provided with a front packaging adhesive film and a cover plate, and the backlight surface of the battery string precursor can be sequentially provided with a rear packaging adhesive film and a back plate to form a laminated member. The front packaging adhesive film and the cover plate arranged on the light facing surface of the battery string precursor can have good light transmittance.

And laminating the laminated body comprising the cell string precursor, wherein in the laminating process, the solder strips are conductively interconnected with the first main grid of one back contact solar cell and the second main grid of the adjacent back contact solar cell which are adhered with the solder strips to obtain the back contact cell assembly. In other words, in the lamination process, the lamination temperature is usually higher than 150 ℃, the solder strip, the first main grid of the back contact solar cell and the second main grid of the adjacent back contact solar cell form conductive interconnection, and at this time, materials such as the front packaging adhesive film, the rear packaging adhesive film and the like on two sides of the cell string precursor in the laminated member have good flexibility, so that the thermal stress in the conductive interconnection process can be fully absorbed, and the warpage is reduced; meanwhile, in the laminating process, the packaging adhesive films and the packaging materials on the two sides of the battery string precursor can limit the position of the battery string precursor properly, and the warping caused by thermal stress can be reduced properly. For example, by adopting the production method of the embodiment of the invention, the warp of the back contact battery assembly produced is less than or equal to 0.5mm, the reliability of the assembly can be improved, and the requirement of mass production can be met. Meanwhile, welding of welding strips before lamination is reduced, welding cost is saved, and production cost is reduced.

Optionally, an adhesive comprising: the adhesive tape and/or the thermosetting adhesive have low cost and good bonding performance, do not bring impurities into a back contact battery assembly in the laminating process, and have simple bonding process.

Optionally, the material of the thermosetting adhesive is selected from: the thermosetting adhesive is at least one of acrylic resin, rubber resin, silicon resin, epoxy resin, polyvinyl ether, polyvinyl butyral, ethylene-vinyl acetate, polymethyl methacrylate, methyl methacrylate copolymer, methacrylic acid copolymer and acrylic acid copolymer, has low cost and good bonding performance, does not bring impurities into a back contact battery assembly in the laminating process, and has simple bonding process.

Optionally, the adhesive tape includes a substrate and glue disposed on a surface of the substrate. The material of the substrate is selected from: polyethylene terephthalate (PET) and/or polyimide, wherein the glue is at least one selected from silica gel glue, rubber glue and acrylic glue. The adhesive tape has the advantages of low cost, good adhesive property, no impurity brought into the back contact battery assembly in the laminating process, and simple adhesive process. In the environment lower than the laminating temperature, the adhesive tape of the material has good bonding performance all the time, in the environment reaching the laminating temperature, the adhesive tape of the material can be melted and is integrated with the front packaging adhesive film and the rear packaging adhesive film, and the height of the adhesive tape is usually low, so that the height difference does not exist in the battery string precursor basically, and the problem of unreliable conductive connection can be avoided.

Optionally, one side or both sides of sticky tape are provided with from the type layer, tear before using the sticky tape and leave from the type layer, be convenient for the save and the transportation etc. of sticky tape.

Optionally, in the case that the adhesive is a thermosetting adhesive, before step S2, the method further includes: curing the cell string precursor; the curing temperature is less than or equal to 150 ℃, the curing time is less than or equal to 3 minutes, the heating rate in the curing process can be less than or equal to 10 ℃/s, the heating rate is mild, and the curing process is stable, so that the bonding of the solder strip and the first main grid of the back contact solar cell and the bonding of the second main grid of the adjacent back contact solar cell are firmer. The curing temperature, the curing time and the heating speed can fully cure the thermosetting adhesive, the curing process is stable, in the curing process, in the cell string precursor, the solder strip, the first main grid of the back contact solar cell and the second main grid of the adjacent back contact solar cell are not connected with each other in a conductive manner, no thermal stress exists, and no warping is caused.

In the embodiment of the invention, a curing mechanism can be arranged, and the curing mechanism can be integrated with the sizing mechanism and is cured before lamination after bonding, so that the bonding force is improved.

Optionally, the step S1 may include: disposing the adhesive on each of the bonding points of the first main grid of one back-contact solar cell and each of the bonding points of the second main grid of an adjacent back-contact solar cell; placing the solder strips on a first main grid of a back contact solar cell provided with the adhesive and a second main grid of an adjacent back contact solar cell; and applying force to the surface of the solder strip away from the first main grid, so that the solder strip is bonded to each bonding point of the first main grid of one back contact solar cell and each bonding point of the second main grid of the adjacent back contact solar cell through the adhesive. That is, the adhesive is disposed on each of the adhesive points of the first main grid of the back-contact solar cell and each of the adhesive points of the second main grid of the adjacent back-contact solar cell, and then pressure is applied from the surface of the solder strip away from the first main grid.

Optionally, the number of the bonding points on each first main grid is 2-10; the number of the bonding points on each second main grid is 2-10; the size of the adhesive on each of the bonding points in a direction parallel to the first main grid or the second main grid is: 0.5-5 mm. The number of the bonding points and the size of the adhesive on the bonding points not only enable the bonding performance to be good, but also cannot influence the conductive interconnection of the solder strip and the first main grid and the second main grid in the laminating process.

Alternatively, as shown in fig. 2, the first main gate 21 and/or the second main gate 22 is composed of a pad 211 and a thin gate line 212 connecting adjacent pads 211. The number of the bonding pads 211 on each first main grid 21 or each second main grid 22 can be 6-20, and the width of the fine grid lines 212 can be smaller than that of the bonding pads 212 for the whole cell. The pads may be formed by printing and sintering a silver-containing paste or by plating a silver-containing metal or metal stack. The shape of the bonding pad can be any suitable shape such as a circle, a rectangle or an ellipse.

In the above-described cell string precursor, the adhesive is located within the projection of the fine gate lines, that is, in the cell string precursor, the adhesive is in contact with the fine gate lines of the first and second main gates, but is not in contact with the pads of the first and second main gates. And in the laminating process, the welding strips are conductively interconnected with each welding pad of the first main grid and each welding pad of the second main grid to obtain the back contact battery assembly. That is, the adhesive is not located in the location of the conductive interconnects and thus the adhesive does not affect the reliability of the conductive interconnects.

Optionally, before the step S1, the method may further include the steps of: applying solder paste on each pad of the first main gate; and/or applying solder paste on each pad of the second main grid; the melting point of the soldering paste is less than or equal to 150 ℃. The solder paste may be a low temperature solder paste containing SnBi, and if the back contact solar cell forming the string precursor is a monolithic cell, the solder paste may be applied on the first and/or second main grid at any time period before the adhesive is disposed. If the back contact solar cell forming the cell string precursor is a segmented cell, solder paste may be applied to the first and/or second master grids before the adhesive is applied, before the segmentation or after the segmentation. Applying solder paste after slicing can avoid the influence of laser slicing on the solder paste.

Solder paste can be applied to each pad of the first main grid in a printing mode; and/or applying solder paste on each pad of the second main gate. The printing mode can be screen printing or steel screen printing, the solder paste is aligned with the center of the bonding pad when being printed, and the printing size is smaller than the size of the bonding pad. The melting point of the solder paste is less than or equal to 150 ℃, and the melting point is less than the laminating temperature, and the solder paste is applied to each bonding pad of the first main grid; and/or applying solder paste to the respective pads of the second main grid, on the one hand, may further facilitate a stable and secure electrical connection of the solder ribbon to the pads of the first main grid and the pads of the second main grid during the lamination process. On the other hand, the solder paste is arranged on the bonding pad, the height of the bonding pad and the solder paste is basically equal to the height of the thin grid line and the adhesive, the height difference does not exist basically, and the problem that the conductive connection is unreliable can be avoided.

If the solder ribbon is a low-melting-point solder ribbon, it is not necessary to apply solder paste to each pad of the first main grid; and/or without applying solder paste to the respective pads of the second main gate. In the embodiment of the present invention, this is not particularly limited.

Optionally, the solder strip comprises a substrate and a low-melting-point conductive coating coated on the surface of the substrate, the melting point of the low-melting-point conductive coating may be less than or equal to the lamination temperature, and in the lamination process, the low-melting-point conductive coating is melted to realize stable and firm electrical connection with the first main grid and the second main grid, so that stable and firm electrical connection of the solder strip with the first main grid and the second main grid can be further promoted in the lamination process. The material of the low melting point conductive coating is selected from: low melting point metals and/or low melting point alloys.

Optionally, the material of the low melting point conductive coating is selected from: at least one of silver (Ag), bismuth (Bi), cadmium (Cd), gallium (Ga), indium (In), lead (Pb), tin (Sn), titanium (Ti) and zinc (Zn).

Under the condition that the solder strip consists of a base body and a low-melting-point conductive coating coated on the surface of the base body, solder paste does not need to be applied to each bonding pad of the first main grid; and/or without applying solder paste to the respective pads of the second main gate.

In the embodiment of the invention, the welding strips are adhered to the first main grid of one back contact solar cell and the second main grid of the adjacent back contact solar cell by using an adhesive to obtain a cell string precursor; the polarity of the first main grid is opposite to that of the second main grid; and laminating the laminated body comprising the cell string precursor, wherein in the laminating process, the welding strips are conductively interconnected with the first main grid and the second main grid to obtain the back contact cell assembly. In the embodiment of the invention, the welding strips are not welded on the first main grid and the second main grid before lamination, but are bonded before lamination, so that no thermal stress is generated in the bonding process, the welding strips, the first main grid and the second main grid are conductively interconnected in the lamination process, and packaging adhesive films and other materials on two sides of the cell string precursor in the lamination process have good flexibility, so that the thermal stress in the conductive interconnection process can be fully absorbed, and the warping is reduced; meanwhile, in the laminating process, the packaging adhesive films and the packaging materials on the two sides of the battery string precursor can limit the position of the battery string precursor properly, and the warping caused by thermal stress can be reduced properly. Meanwhile, welding of welding strips before lamination is reduced, welding cost is saved, and production cost is reduced.

It should be noted that, for simplicity of description, the method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the embodiments are not limited by the order of acts described, as some steps may occur in other orders or concurrently depending on the embodiments. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the embodiments of the application.

In an embodiment of the present invention, a system for producing a back contact battery assembly is also provided, which is used for performing the above-mentioned method for producing a back contact battery assembly. Referring to fig. 4, fig. 4 is a schematic view showing a partial structure of a system for producing a back contact battery pack according to an embodiment of the present invention. The back contact battery assembly production system includes: an adhesive mechanism 3 and a laminating mechanism (not shown in fig. 4).

The bonding mechanism 3 is used for bonding the solder strips to a first main grid of one back contact solar cell and a second main grid of an adjacent back contact solar cell by adopting an adhesive to obtain a cell string precursor; the first main gate and the second main gate have opposite polarities.

A lamination mechanism for laminating the stack including the cell string precursor to obtain a back contact cell assembly; the solder strip is conductively interconnected with the first and second main gates during lamination.

The adhesive, the back contact solar cell, the first main grid, the second main grid, the cell string precursor, the stack, and the like may be referred to the above description, and thus, the description thereof is omitted to avoid redundancy. The back contact battery pack production system can achieve the same beneficial effects as the back contact battery pack production method.

Alternatively, referring to fig. 4, the bonding mechanism 3 may include: an adhesive application section 31, a solder ribbon placement section (not shown in fig. 4), and a nip section 32.

An adhesive applying part 31 for applying the adhesive on each of the adhesive points of the first main grid of one back-contact solar cell and the adhesive points of the second main grid of the adjacent back-contact solar cell;

and a solder ribbon placement section for placing the solder ribbon on the first main grid of the back contact solar cell provided with the adhesive and the second main grid of the adjacent back contact solar cell. The solder strip placing portion may further perform operations such as straightening, cutting, and carrying the solder strip, which is not particularly limited in the embodiment of the present invention.

And the pressing part 32 is used for applying acting force on the surface of the welding strip away from the first main grid, so that the welding strip is adhered to each adhering point of the first main grid of one back contact solar cell and each adhering point of the second main grid of the adjacent back contact solar cell through the adhesive.

In the case that the adhesive is a thermosetting adhesive, the glue applying portion 31 may be specifically a glue dispensing gun in which the thermosetting adhesive is stored, and a glue head of the glue dispensing gun is used for dispensing glue on each bonding point of the first main grid of one back-contact solar cell and each bonding point of the second main grid of the adjacent back-contact solar cell. In the case where the adhesive is an adhesive tape, the glue applying portion 31 may cut the adhesive tape to an appropriate size and lay the adhesive tape on each of the bonding points of the first main grid of one back-contact solar cell and each of the bonding points of the second main grid of the adjacent back-contact solar cell. The laying may be in a lattice form.

Optionally, the position of the pressing part 32 applying the acting force on the solder strip is staggered with the position of the bonding point, so that in the process of applying the acting force on the pressing part 32, even if part of the adhesive is extruded, the adhesive is not bonded on the pressing part 32, the pressing part 32 is not polluted, and the service life of the pressing part 32 is long.

Optionally, the pressing portion 32 may be a spring pressing pin, and in the applying process, adverse pressure influence on the solder strip, the back contact solar cell, the first main grid or the second main grid may be avoided through elastic deformation.

Alternatively, in the case where the adhesive is a thermosetting adhesive, referring to fig. 4, the back contact battery assembly production system may further include: a curing mechanism 4 for curing the cell string precursor; the curing temperature is less than or equal to 150 ℃, the curing time is less than or equal to 3 minutes, and the heating speed in the curing process is less than or equal to 10 ℃/s. In fig. 4, the arrows above the bonding portion 32 and below the back contact solar cell 2 in the curing mechanism 4 may indicate heating during the curing process.

In fig. 4, 11 may be a solder strip and 2 may be a back contact solar cell. The position of the workpiece can be transferred between the various mechanisms or components by the transfer mechanism 5. In the embodiment of the present invention, this is not particularly limited.

The following may be a specific process for producing a back contact battery assembly by means of the above-described back contact battery assembly production system:

and printing solder paste on each pad of the first main grid and the second main grid of the back contact solar cell. And carrying out laser scribing on the back contact solar cell printed with the solder paste, taking a scribing half as an example, and scribing the whole cell into an A half and a B half, wherein the AB half is symmetrical in graph.

After the first A half piece is arranged and aligned, the first A half piece is placed on the transmission mechanism 5. In the case where the first a half is conveyed to a position where the glue applying portion 31 is suitable for applying glue, the glue applying portion 31 applies glue on the fine grid of the first main grid, the fine grid of the second main grid of the first a half. The solder strip placement part is used for straightening, cutting and aligning the first group of solder strips and then is placed on the P area (or N area) main grid line of the first A half piece, wherein half of the solder strips are arranged outside the battery conveying direction. The first press 32 presses the solder ribbon on the outside of the first a half cell in the conveying direction, and the transport mechanism 5 conveys the first a half cell forward by one station. After the second A half piece is arranged and aligned, the second A half piece is placed on the transmission mechanism 5 and rotated for 180 degrees. In the case where the second a half is conveyed to a position where the glue applying portion 31 is suitable for applying glue, the glue applying portion 31 applies glue to the fine grid of the first main grid, the fine grid of the second main grid of the second a half.

The solder strip placing part is used for straightening, cutting and aligning the second group of solder strips, and then placing the solder strips on the first A half N-area (or P-area) main grid line and the second A half P-area (or N-area) main grid line. The second press 32 presses the solder strip on the first a half cell. The step of conveying the next a half piece by the conveying mechanism 5 to move forward one station to the second pressing part 32 to press the solder strip on the next a half piece is circularly executed.

The curing mechanism 4 finishes glue curing and gradually cools the first A half piece. The curing mechanism 4 finishes glue curing on the second A half piece and gradually reduces the temperature. The back contact battery assembly production system may also include a nip recovery mechanism (not shown in fig. 4). The nip recovery mechanism recovers the first nip 32. The nip recovery mechanism may transport the nip 32 back to the position behind the glue application section 31 after the curing is completed. The nip recovery mechanism, without the curing mechanism or without performing the curing step, may transport the nip 32 back to a position after the application of the first force, to the glue application section 31. The curing process is performed for the different a half sheets, respectively, resulting in a string of cell string precursors.

And performing component typesetting on the multi-string battery string precursor, and laminating the front packaging adhesive film, the rear packaging adhesive film, the cover plate and the back plate to obtain the laminated member. And laminating the laminated piece by adopting a laminating mechanism to obtain the back contact battery assembly. The solder strip is conductively interconnected with the first and second main gates during lamination

Optionally, the operations of framing the assembly and attaching the wire box can be continued. In the embodiment of the present invention, this is not particularly limited.

It should be noted that the system embodiment can achieve the same or similar advantages as the method embodiment. And the method embodiment and the system embodiment can be referred to each other, and related parts are abbreviated to avoid repetition.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal (such as a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.