Method for fixing battery string in photovoltaic module

Abstract

The invention discloses a method for fixing a battery string in a photovoltaic module, which comprises back glass and front glass, a battery string layer is positioned between the front glass and the back glass, a sealing layer is used for bonding and fixing the battery string layer with the front glass and the back glass, a first sealing layer is formed between the back glass and the battery string layer, and a second sealing layer is formed between the front glass and the battery string layer. A second sealing layer is formed between the front glass and the battery string layer, the periphery between the front glass and the back glass is sealed and packaged by the packaging layer, a sealing strip is arranged between the back glass and the first sealing layer, the sealing strip extends in the direction of the short edge of the back glass, and the sealing strip is separated from the edge of the short edge of the back glass. According to the invention, the surface of the adhesive tape is very smooth, the adhesive tape does not have any bonding force with the EVA in the area fixed by the adhesive tape, and the part can quickly appear complete in the area along with the use of the assembly, and the product quality is good.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic modules, and particularly to a method for fixing battery strings in a photovoltaic module. Background Art

[0002] In the production process of existing photovoltaic modules, high-temperature resistant transparent tape is used to paste and fix two adjacent battery strings in the module; After the existing technology uses tape for fixing, the tape that is not firmly pasted will be sucked on the front surface of the module during the lamination process, affecting the appearance beauty of the module; in addition, as the module is used outdoors, the tape will turn yellow and affect the appearance. Finally, the surface of the tape is very smooth, and in the area fixed by the tape, there is no adhesion between the tape and the EVA. With the use of the module, bulges and delamination will quickly appear in this area, seriously affecting the product quality. Therefore, a method for fixing battery strings in a photovoltaic module is needed. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems of bulges and delamination in the existing technology that seriously affect the product quality, and thus propose a method for fixing battery strings in a photovoltaic module.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: including a back glass and a front glass, a battery string layer, the battery string layer is located between the front glass and the back glass, a sealing layer, the sealing layer is used to bond and fix the battery string layer with the front glass and the back glass, a first sealing layer is formed between the back glass and the battery string layer, a second sealing layer is formed between the front glass and the battery string layer, an encapsulation layer, the encapsulation layer seals and encapsulates the periphery between the front glass and the back glass. Among them, a sealing strip is provided between the back glass and the first sealing layer, the sealing strip extends along the short side direction of the back glass, and the sealing strip is spaced apart from the edge of the short side of the back glass; a method for fixing battery strings in a photovoltaic module, step one, first lay a layer of EVA on the glass surface; step two, lay the battery strings according to the component design requirements, and the distance between the battery strings is 1 mm - 5 mm; step three, lay another layer of EVA on the surface of the battery cells; step four, then use a soldering iron to heat the upper layer of EVA to make the EVA bond with the underlying battery strings, and through the bonding of the EVA, the position fixation between the battery strings is achieved.

[0005] Further preferably, the temperature used for heating the EVA is 100 degrees Celsius - 400 degrees Celsius; the heating time is set to a corresponding time according to different temperatures, and the time is 1 s - 10 s.

[0006] Further preferably, the area of the EVA heated on the surface of a single cell is between 1 square millimeter and 100 square centimeters.

[0007] Further preferably, the soldering iron tip can be a single one, and the heating and fixing are carried out one by one in sequence; or multiple heads can be used to heat different positions of the EVA simultaneously to achieve heating and fixing at multiple locations at one time.

[0008] Further preferably, the cell has a front side and a back side, there is no main grid on the front side and the back side, and fine grid lines are provided on both the front side and the back side; the conductive strip is at least one, and the conductive strip is used to connect multiple pieces of the cells, wherein the conductive strip is in contact with the fine grid lines on the front side and the back side of the cell by means of a conductive material in a manner capable of collecting current; more than 75% of the outer peripheral surface of the conductive strip is covered by the conductive material, and in the axial direction of the conductive strip, the conductive material continuously covers the outer peripheral surface of the conductive strip; the connection between the conductive material and the outer peripheral surface of the conductive strip is carried out by a process of heating and melting metal. The beneficial effect of the present invention is that: the surface of the tape is very smooth, in the area fixed by the tape, there is no adhesion force between the tape and the EVA, and with the use of the component, a complete area will soon appear in this area, and the product has good quality and other advantages; By locally heating and fixing the EVA and the battery string before lamination, the use of tape for fixing is avoided, and problems such as later blistering and bulging caused by the tape are avoided, improving the product quality. Specific embodiments

[0009] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0010] A method for fixing a battery string in a photovoltaic module. Step 1: First, lay a layer of EVA on the glass surface; Step 2: Lay the battery string according to the component design requirements, and the distance between the battery strings is 1 mm - 5 mm; Step 3: Lay another layer of EVA on the surface of the cell; Step 4: Then use a soldering iron to heat the upper layer of EVA so that the EVA is bonded to the following battery string, and through the bonding of the EVA, the position fixation between the battery strings is achieved.

[0011] Preferably, the temperature for heating EVA is 100 °C - 400 °C; the heating time is set according to the temperature, and the time is 1 s - 10 s. The area of the EVA heated on the surface of a single solar cell is 1 square millimeter - 100 square centimeters. The soldering iron tip can be a single one, and the heating and fixing are carried out one by one in sequence; or multiple heads can be used to heat different positions of the EVA simultaneously to achieve heating and fixing at multiple locations at one time. During specific implementation, a layer of EVA is laid on the glass surface, and then the solar cell string is laid according to the requirements of the design drawing. Finally, another layer of EVA is laid flat. Since EVA is in a semi-transparent state, the position of the solar cell string can be easily seen with the naked eye. Multiple soldering iron tips are used to fix adjacent solar cell strings. The area of a single soldering iron tip is 4 square centimeters, with 6 in the horizontal direction and 12 in the vertical direction, a total of 72. The temperature is set at 150 °C and the time is 1 s. Then the soldering iron tip group is moved above the back EVA and slowly pressed onto the back EVA to melt the EVA and paste the solar cells. After the position of the solar cell string is fixed, the back glass or backplane is laid, and the lamination of the component and the production of subsequent processes are carried out.

[0012] Back glass and front glass, solar cell string layer, the solar cell string layer is located between the front glass and the back glass, sealing layer, The sealing layer is used to bond and fix the solar cell string layer to the front glass and the back glass, forming a first sealing layer between the back glass and the solar cell string layer, and a second sealing layer between the front glass and the solar cell string layer. Encapsulation layer, the encapsulation layer seals and encapsulates the periphery between the front glass and the back glass. Among them, a sealing strip is provided between the back glass and the first sealing layer, and the sealing strip extends along the short side direction of the back glass, and the sealing strip is spaced apart from the edge of the short side of the back glass; During implementation, the width of the sealing strip 2 is 10 mm - 50 mm, such as 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, and the distance between the sealing strip 2 and the short side edge of the back glass is 2 mm - 5 mm, such as 2 mm, 3 mm, 4 mm, 5 mm. If the width of the sealing strip 2 is too wide, glue leakage will occur due to excessive glue flow. If the width of the sealing strip is too narrow, it will affect the formed thickness, and thus affect the pressure buffering. The distance between the sealing strip 2 and the short side edge of the back glass 1 is between 2 mm and 5 mm. The pressure from itself or the lamination pressure will be transmitted to the first sealing layer along the sealing strip, and the pressure distribution transmitted to the first sealing layer is relatively uniform, reducing the fragment rate; According to a specific embodiment of the present invention, a sealing block is provided at the lead-out position between the first sealing layer 3 and the back glass 1. Setting the sealing block here can make up for the insufficient sealing caused by the opening of the back glass at the lead-out position, thereby causing the problem of empty glue. Moreover, the sealing block is placed between the first sealing layer and the back glass. During the lamination process, the pressure of the sealing block will be first transmitted to the entire first sealing layer, and then to the battery string layer, and the battery string layer will not be locally overstressed and cracked; According to a specific embodiment of the present invention, both sides of the encapsulation layer are respectively pasted on the edges of the outer sides of the front glass and the back glass to form an arc convex surface around the periphery between the front glass and the back glass. This makes the encapsulation layer 7 spaced apart from the outer sides of the front glass 6 and the back glass 1 to form a certain space, avoiding the sealing material from overflowing from the edge during the lamination process and polluting the laminator and the surrounding environment, and the air bubbles formed in the sealing material can also be discharged from the component in time.

[0013] On the other hand, the present invention proposes a method for manufacturing a double-glass photovoltaic module. According to the embodiments of the present invention, the manufacturing method includes: Laminating step: sequentially lay a second sealing layer 5, a battery string layer 4, a first sealing layer 3, a sealing strip 2, and a back glass 1 on the front glass 6 to form a laminate; In some specific embodiments, during the lamination process of the double-glass photovoltaic module, first lay a second sealing layer on the front glass 6, then place the battery string, perform series and parallel welding on the battery string according to the design drawing, then place a sealing strip 2 with a width of 10 - 50 mm in the short side direction of the front glass 6, place it inside 2 - 5 mm away from the short side edge of the front glass 6, continue to lay the back first sealing layer 3, and finally place the back glass 1 to complete the lamination work. Then, whether it is the pressure from the back glass 1 itself or the pressure during lamination, after the buffering of the sealing strip 2 and the surface equalizing pressure effect of the first sealing layer 3, the pressure finally transmitted to the battery string layer 4 is small and evenly distributed, avoiding the situation of fragmentation caused by large and uneven pressure, and effectively reducing the fragmentation rate of the double-glass photovoltaic module. In addition, the sealing strip 2 can effectively reduce the bubble problem around the component after lamination due to lack of glue.

[0014] In some specific embodiments, a sealing block is placed at the lead-out position between the first sealing layer 3 and the back glass 1. The sealing block is placed above the back glass 1. During the lamination process, the pressure of the sealing block will be first transmitted to the entire first sealing layer and then to the battery string, and the battery string will not be locally overstressed and cracked.

[0015] The solar cell has a front side and a back side, without main grids on the front and back sides, and fine grid lines are provided on both the front and back sides. There is at least one conductive strip, and the conductive strip is used to connect multiple solar cells. Among them, the conductive strip contacts the fine grid lines on the front side and the back side of the solar cell in a manner that can collect current by means of a conductive material; more than 75% of the outer peripheral surface area of the conductive strip is covered by the conductive material, and in the direction along the axis of the conductive strip, the conductive material continuously covers the outer peripheral surface of the conductive strip; the connection between the conductive material and the outer peripheral surface of the conductive strip is achieved through a process of heating and melting metal. The conductive strip 5 covered by the conductive material electrically connects multiple solar cells, outputs the electrical energy of the solar cells, and realizes the series connection of the solar cells, etc. Among them, the conductive strip is connected to the front side and the back side of the solar cell 1 by means of a conductive material. In a specific embodiment, five conductive strips 5 are respectively provided on the front side and the back side of each solar cell. However, other numbers of conductive strips, such as 1, 2, 3, 4, 6, 7, 9, 10, 11, 12, 13, 14, 15 conductive strips are also allowed.

[0016] The conductive strip 5 covered by the conductive material is in the form of a continuous strip and transversely traverses each fine grid line 2 along the longitudinal direction and is fixed on the front side and the back side of the solar cell. In this way, multiple solar cells are connected in series through the corresponding conductive strips to form a battery string. The following uses two specific embodiments to illustrate the welding process between the conductive strip and the solar cell. It should be noted that generally, the polarities of the front side and the back side of the solar cell are opposite. During the process of connecting the solar cells in series in a solar module, generally, different polar sides of the previous solar cell and the next solar cell need to be connected together. It should be understood that the following description is only an exemplary illustration and not a specific limitation of the invention.

[0017] Example 1: In this module, the front side of the previous solar cell 4 and the front side of the next solar cell 4 are on the same surface. The front side of the previous solar cell 4 needs to be welded to the back side of the next solar cell 4. At this time, the conductive strip 5 covered by the conductive material needs to be welded to the solar cell 4 one by one to realize the series connection between the front side of the previous solar cell 4 and the back side of the next solar cell 4.

[0018] Example 2: In this module, the front side and the back side of the solar cell 4 are arranged alternately, that is, the front side of the previous solar cell 4 and the back side of the next solar cell 4 are on the same surface. At this time, the conductive strip 5 covered by the conductive material can be welded to multiple solar cells in one piece to realize the series connection between the front side of the previous solar cell 4 and the back side of the next solar cell 4.

[0019] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, making equivalent replacements or changes should be covered within the protection scope of the present invention.

Claims

1. A method for fixing a battery string in a photovoltaic module, comprising: The battery string layer comprises a back glass and a front glass, wherein the battery string layer is located between the front glass and the back glass, the sealing layer is used to bond and fix the battery string layer to the front glass and the back glass, a first sealing layer is formed between the back glass and the battery string layer, a second sealing layer is formed between the front glass and the battery string layer, and the encapsulation layer seals the front glass and the back glass on all sides, wherein a sealing strip is arranged between the back glass and the first sealing layer, the sealing strip extends along the short side direction of the back glass, and the sealing strip is spaced apart from the edge of the short side of the back glass; Step 1: First, lay a layer of EVA on the glass surface; Step 2: Lay out battery strings according to component design requirements, with a distance of 1mm-5mm between battery strings; Step 3: Lay another layer of EVA on the surface of the battery cell; Step 4: Use a soldering iron to heat the upper layer of EVA so that the EVA is bonded to the battery string below. The position of the battery strings is fixed by bonding the EVA.

2. The method for fixing a battery string in a photovoltaic module according to claim 1, characterized in that: The temperature used for EVA heating is 100 degrees Celsius-400 degrees Celsius; the heating time is set according to the temperature, and the time is 1s-10s;.

3. The method for fixing a battery string in a photovoltaic module according to claim 1, characterized in that: The area of ​​EVA heated on the surface of a single cell is between 1 square millimeter and 100 square centimeters.

4. The method for fixing a battery string in a photovoltaic module according to claim 1, characterized in that: The soldering iron tip can be an independent one, which is heated and fixed one by one in sequence; or multiple tips can be used to heat EVA at different positions at the same time, so that heating and fixing of multiple places can be achieved at one time.

5. The method for fixing a battery string in a photovoltaic module according to claim 1, characterized in that: The battery cell has a front side and a back side, the front side and the back side have no main grid, the front side and the back side are both provided with fine grid lines, there is at least one conductive tape, and the conductive tape is used to connect multiple battery cells, wherein the conductive tape is in contact with the fine grid lines on the front side and the fine grid lines on the back side of the battery cell by means of conductive material in a manner capable of collecting current; the outer peripheral surface of the conductive tape is covered by the conductive material with a coverage area greater than 75%, and the conductive material is continuously covered on the outer peripheral surface of the conductive tape in the axial direction of the conductive tape; the conductive material and the outer peripheral surface of the conductive tape are connected by a process of heating molten metal.