Back contact solar cell and interconnection electrode fixing method

Abstract

The invention discloses a method for fixing a back contact solar cell and an interconnected electrode, which comprises the following steps of: printing positive and negative electrode auxiliary grid lines on an I BC solar cell to be fixed without a main grid, and printing insulating glue according to the positions of the grid lines; printing solder paste and UV glue points on the back electrode of the I BC solar cell; preparing a solder strip in advance according to the solder strip design, placing the solder strip in parallel according to a back electrode column of the IBC solar cell, and irradiating UV glue points by adopting a UV lamp for curing; the I BC solar cells are longitudinally placed into groups according to columns, welding strips are laid on the I BC solar cells, UV lamps are adopted to carry out irradiation on the welding strips and the I BC solar cells in a bonding mode, and a battery pack is manufactured; and carrying out a lamination process on the battery pack and the interconnected electrodes to prepare the assembly. By adopting the main-grid-free battery, the main grid silver paste is saved, the assembly cost is reduced, the narrow local widened welding strip is compatible, the shading loss caused by the welding strip is reduced, and the double-sided rate of the manufactured double-sided assembly is high.

Description

Technical Field

[0001] The invention relates to the field of battery electrode fixing, and in particular to a method for fixing a back contact solar cell and interconnecting electrodes. Background Art

[0002] As the global demand for renewable energy continues to grow, the importance of solar energy as a clean, renewable energy form is becoming increasingly prominent. As an important innovation in solar cell technology, back-contact solar cells effectively improve the photoelectric conversion efficiency of the cell by placing the electrode on the back of the cell and adopting an interdigitated structure, while reducing the front surface shading and parasitic resistance losses. However, the manufacturing of IBC cells and the electrode interconnection and fixing technology are still one of the key challenges in achieving efficient and reliable solar modules.

[0003] For example, patent number CN106001962A discloses a method and device for welding and heating solar cells and fixing welding strips, wherein the welding strip fixing device is provided with an iron block embedded with a pressing block, a pressing block, a pressure sensor, an infrared sensor and a cell conveying rack; the pressing block is embedded in the iron block, the pressure sensor and the infrared sensor are arranged at the lower part of the pressing block, the pressure sensor is used to detect the distance between the pressing block and the welding strip, and the infrared sensor is used to detect the contact pressure between the pressing block and the welding strip; the welding strip is arranged under the pressing block and laid on the grid line position of the cell, and the cell is arranged on the cell conveying rack; the cell welding and heating device is provided with five electromagnetic welding heads, and the five electromagnetic welding heads are respectively arranged on five iron blocks embedded with electromagnetic welding heads, and lifting rods are respectively arranged between the five iron blocks embedded with electromagnetic welding heads and the base.

[0004] However, the traditional string welding process requires infrared heating with high energy consumption, and a large amount of organic components in the flux will volatilize in the high temperature area, which is highly polluting; the traditional string welding process welds two cells at a time and cycles back and forth, which is inefficient; the traditional string welding process has a high temperature rise and rapid cooling of the cells and welding strips. On the IBC battery string, due to the large difference in thermal expansion coefficient between the welding strip metal material and the battery silicon substrate, the battery will be bulged after welding, the thermal stress in the battery string is large, and the risk of fragmentation is high during the assembly production process. Therefore, a method for fixing solar cells and interconnecting electrodes that solves the above problems is needed. Summary of the invention

[0005] The object of the present invention is to provide a method for fixing a back contact solar cell and an interconnecting electrode in view of the above problems.

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

[0007] The present invention comprises the following steps:

[0008] A. printing positive and negative auxiliary grid lines on the IBC solar cell without main grid to be fixed, and printing insulating glue according to the position of the grid lines;

[0009] B. Printing solder paste and UV glue dots on the back electrode of the IBC solar cell;

[0010] C. Pre-fabricate the solder strip according to the solder strip design, place the solder strip in parallel with the back electrode array of the IBC solar cell, and use a UV lamp to irradiate the UV glue point for curing;

[0011] D. Arranging the IBC solar cells in a row and in a longitudinal direction to form a group, laying a welding tape on the IBC solar cells, and using a UV lamp to bond the welding tape to the IBC solar cells and irradiate them to form a battery pack;

[0012] E. Performing a lamination process on the battery pack and interconnecting electrodes to form an assembly.

[0013] Furthermore, the solder paste is printed on the busbar-free IBC solar cell to be fixed to avoid the UV glue printing position. Furthermore, the printing method of the UV glue point includes single-sided bonding of wide solder strips, local widening of both sides of narrow solder strips or single-sided bonding.

[0014] Furthermore, the solder strip design includes selecting a wide solder strip, printing UV glue dots on one edge of the solder strip to bond the battery cell, and adjusting the solder paste printing position to the other side of the solder strip.

[0015] Furthermore, the solder strip design includes selecting a circular solder strip for partial flattening or cutting into a widened strip, the UV adhesive joint is located at one or both side edges of the widened portion, and the solder paste is printed under the solder strip to avoid the UV adhesive point.

[0016] Furthermore, the solder strip placement includes placing solder paste on one side of the wide solder strip, placing solder paste on the other side, and placing solder paste in the middle of the widened position of the thin solder strip.

[0017] Furthermore, the laying of the solder strip includes aligning one side edge of the solder strip with the UV glue spot, and aligning one side or both side edges of the locally widened portion of the solder strip with the UV glue spot.

[0018] Furthermore, the lamination process: places the stacked battery pack on the support assembly, starts the heating plate to heat the photovoltaic assembly, quickly melts the high-transmittance EVA and ordinary EVA; simultaneously starts the vacuum pushing assembly and the vacuum generating assembly so that the sealing plate seals the feed port and the discharge port; forms a closed space in the vacuum chamber, and uses the vacuum generating assembly to extract the internal air and bubbles in the battery pack; after the temperature rise curve requirements of the high-transmittance EVA and ordinary EVA are met, the support assembly drives the battery pack to rise and detach from the heating plate; the vacuum pushing assembly inflates the sealed cavity, and the air pressure pushes the rubber plate to press the photovoltaic assembly under the action of the spring.

[0019] Compared with the prior art, the present invention provides a method for fixing a back contact solar cell and an interconnecting electrode, which has the following beneficial effects:

[0020] The present invention supports 0BB busbarless batteries, which can save busbar silver paste and reduce component costs. The 0BB solution supports multiple welding strips to reduce battery internal resistance, improve component power generation efficiency, and is compatible with narrower locally widened welding strips. The shading loss caused by the welding strips is low, and the bifacial rate of the bifacial component is high. At the same time, there is no need for string welding and heating, the battery string is flat and has no deformation, the risk of battery damage and internal stress are small, and the manufactured components have better reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a schematic flow chart of a method for fixing a back-contact solar cell and interconnecting electrodes. DETAILED DESCRIPTION

[0022] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0023] like Figure 1 As shown, the present invention comprises the following steps:

[0024] A. printing positive and negative auxiliary grid lines on the IBC solar cell without main grid to be fixed, and printing insulating glue according to the position of the grid lines;

[0025] B. Printing solder paste and UV glue dots on the back electrode of the IBC solar cell;

[0026] C. Pre-fabricate the solder strip according to the solder strip design, place the solder strip in parallel with the back electrode array of the IBC solar cell, and use a UV lamp to irradiate the UV glue point for curing;

[0027] D. Arranging the IBC solar cells in a row and in a longitudinal direction to form a group, laying a welding tape on the IBC solar cells, and using a UV lamp to bond the welding tape to the IBC solar cells and irradiate them to form a battery pack;

[0028] E. Performing a lamination process on the battery pack and interconnecting electrodes to form an assembly.

[0029] In this embodiment, the curing of the insulating adhesive includes thermal curing and UV curing.

[0030] In this embodiment, the solder paste is printed on the busbar-free IBC solar cell to be fixed to avoid the UV glue printing position. Further, the printing method of the UV glue point includes single-sided bonding of wide solder strips, local widening of both sides of narrow solder strips or single-sided bonding.

[0031] In this embodiment, the solder strip design includes selecting a wide solder strip, printing UV glue dots on one edge of the solder strip to bond the battery cell, and adjusting the solder paste printing position to the other side of the solder strip.

[0032] In this embodiment, the solder strip design includes selecting a circular solder strip for partial flattening or cutting into a widened strip, the UV adhesive joint is located at one or both side edges of the widened portion, and the solder paste is printed under the solder strip to avoid the UV adhesive point.

[0033] In this embodiment, the solder strip placement includes placing solder paste on one side of the wide solder strip, placing solder paste on the other side, and placing solder paste in the middle of the widened position of the thin solder strip.

[0034] In this embodiment, laying the solder tape includes aligning one side edge of the solder tape with the UV glue spot, and aligning one side or both side edges of a locally widened portion of the solder tape with the UV glue spot.

[0035] In this embodiment, the lamination process is as follows: placing the stacked battery pack on the support component, starting the heating plate to heat the photovoltaic component, and quickly melting the high-transparency EVA and the ordinary EVA; simultaneously starting the vacuum push component and the vacuum generating component to make the sealing plate seal the feed port and the discharge port; forming a closed space in the vacuum chamber, and using the vacuum generating component to extract the internal air and the bubbles in the battery pack; after the temperature rise curve requirements of the high-transparency EVA and the ordinary EVA are met, the support component drives the battery pack to rise and detach from the heating plate; the vacuum push component inflates the sealed cavity, and the air pressure pushes the rubber plate to press the photovoltaic component under the action of the spring;

[0036] In actual evaluation, the maximum temperature of the film material is 140-160°C.

[0037] In this Example 1, a solder strip with a larger width is selected, UV glue is coated on one edge of the solder strip, the edge of the solder strip coated with UV glue is aligned with the specified position on the battery cell, and a UV light source is used to irradiate the solder strip to cure the UV glue, thereby fixing the solder strip on the battery cell, and solder paste is printed on the other side of the solder strip to ensure electrical connection with the battery cell.

[0038] In this Example 2, a circular solder strip is selected and a partially widened solder strip is formed through a local flattening or cutting process. UV glue is coated on one or both edges of the widened solder strip, and the solder strip coated with UV glue is placed on the battery cell to ensure that the UV glue is positioned correctly. A UV light source is also used to cure the UV glue and fix the solder strip. Solder paste or conductive glue is printed on the non-UV glue area of ​​the solder strip to achieve electrical connection.

[0039] The present invention is a method for fixing solar cells and interconnecting electrodes that abandons the improved string welding process for fixing solar cells and interconnecting electrodes. Two types of solder strips are used: wide solder strips for single-side bonding and narrow solder strips for partial widening of both sides or single-side bonding. Insulating glue and solder paste are printed on IBC cells. UV glue is used to bond the wider solder strip or the partially widened solder strip to the corresponding position of the IBC cell to be fixed, and a battery string is made by UV curing. The solder strip at the position in contact with the UV glue is on one side of the wider solder strip, and solder paste is set on the other side, or solder paste / conductive glue is set in the middle of the widened position of the thinner solder strip.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for fixing a back contact solar cell and an interconnect electrode, characterized in that: The following steps are involved: A. printing positive and negative auxiliary grid lines on the IBC solar cell without main grid to be fixed, and printing insulating glue according to the position of the grid lines; B. Printing solder paste and UV glue dots on the back electrode of the IBC solar cell; C. Pre-fabricate the solder strip according to the solder strip design, place the solder strip in parallel with the back electrode array of the IBC solar cell, and use a UV lamp to irradiate the UV glue point for curing; D. Arranging the IBC solar cells in a row and in a longitudinal direction to form a group, laying a welding tape on the IBC solar cells, and using a UV lamp to bond the welding tape to the IBC solar cells and irradiate them to form a battery pack; E. Performing a lamination process on the battery pack and interconnecting electrodes to form an assembly.

2. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The solder paste is printed on the busbar-free IBC solar cell to be fixed to avoid the UV glue printing position.

3. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The printing method of the UV glue dots includes one-side bonding of wide solder strips and two-side or one-side bonding of narrow solder strips with local widening.

4. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The solder strip design includes selecting a wide solder strip, printing UV glue dots on one edge of the solder strip to bond the battery cell, and adjusting the solder paste printing position to the other side of the solder strip.

5. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The solder strip design includes selecting a circular solder strip to be partially flattened or cut into a widened strip, the UV adhesive joint is located at one or both side edges of the widened portion, and the solder paste is printed under the solder strip to avoid the UV adhesive point.

6. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The solder strip placement includes placing solder paste on one side of the wide solder strip, placing solder paste on the other side, and placing solder paste in the middle of the widened position of the thin solder strip.

7. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The laying of the welding tape comprises aligning one side edge of the welding tape with the UV glue point, and aligning one side or both side edges of the locally widened portion of the welding tape with the UV glue point.

8. The method for fixing a back contact solar cell and an interconnecting electrode according to claim 1, characterized in that: The lamination process comprises the following steps: placing the stacked battery packs on the support assembly, starting the heating plate to heat the photovoltaic assembly, and quickly melting the high-transmittance EVA and the common EVA; simultaneously starting the vacuum pushing assembly and the vacuum generating assembly so that the sealing plate can seal the feed port and the discharge port; forming a closed space in the vacuum chamber, and using the vacuum generating assembly to extract the internal air and the bubbles in the battery pack; after the temperature rise curve requirements of the high-transmittance EVA and the common EVA are met, the support assembly drives the battery pack to rise and detach from the heating plate; the vacuum pushing assembly inflates the sealed cavity, and the air pressure drives the rubber plate to press the photovoltaic assembly under the action of the spring.

Images