Space-free photovoltaic cell

Abstract

The utility model discloses a spacing-free photovoltaic cell, main grids are respectively printed on the front surface and the back surface of the cell, and fine grids are printed between the main grids; the number of the fine grids on the front surface of the battery piece is smaller than that of the fine grids on the back surface of the battery piece; the battery piece comprises an electrode piece with the positive electrode as the front face and an electrode piece with the negative electrode as the front face, the two kinds of electrode pieces are sequentially overlaid, and the positive electrodes and the negative electrodes are arranged alternately, through the battery piece, the welding strip does not need to be connected with the front face and the back face of the battery piece at the same time, and therefore gaps between the battery pieces do not need to be reserved. And the effect of reducing the welding strip consumption is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic components, in particular to a photovoltaic cell sheet without spacing. Background Art

[0002] Photovoltaic power generation has become increasingly popular due to its minimal environmental and site requirements, coupled with rapid technological development. Currently, silicon solar cells are the most widely used on the market. Their high power generation efficiency and mature production processes have narrowed the gap in power generation costs with traditional energy sources.

[0003] PERC cells, or Passivated Emitter Rear Contact solar cells, have received widespread attention. Currently, there are two main types of PERC cells: monofacial PERC cells, whose back surface is fully covered with aluminum paste, and bifacial PERC cells, whose back surface is covered with aluminum grids. Monofacial PERC cells have a fully aluminum back surface, making them opaque, while bifacial PERC cells have aluminum grids on the back, allowing light to pass through a limited range of wavelengths. As a result, bifacial cells exhibit a certain efficiency difference compared to monofacial cells, primarily due to the loss of long-wavelength light.

[0004] The structure of a bifacial solar cell includes a textured topography on both the front and back sides, a PN structure emitter, a passivated anti-reflective dielectric layer, and front and back electrodes. The relative positioning of the front and back gridlines affects light reflection on the back side. Existing bifacial PERC cells have fine gridlines on the front and back sides that are essentially arranged face-to-face. Light enters from the front side, transmits through the silicon substrate, then to the back side, and finally escapes the cell, resulting in light loss. Therefore, utilizing this loss is a key approach to improving the efficiency of bifacial PERC cells.

[0005] Chinese patent document CN107671414A discloses a "double-sided battery structure." This structure includes a battery cell body, front main grid lines and front fine grid lines arranged on the front of the battery cell body, and back main grid lines and back fine grid lines arranged on the back of the battery cell body. The front main grid lines and the front fine grid lines intersect, and the back main grid lines and the back fine grid lines intersect. The back fine grid lines project onto the front of the battery cell body between the front fine grid lines. This technical solution wastes space and consumes a large amount of solder ribbon. Summary of the Invention

[0006] The utility model mainly solves the technical problems of space waste and large amount of welding ribbon used in the original technical solution, and provides a photovoltaic cell without spacing. The positive and negative poles can be on the same plane by staggered printing of grid lines, and finally the adjacent cells can be attached to each other without spacing at the end of the component manufacturing. At the same time, by reducing the width of the cell and placing the photovoltaic components of the cells alternately with the positive and negative cells, the welding ribbon does not need to connect the front and back of the cell at the same time, so that the gap between the cell cells does not need to be retained, thereby achieving the effect of reducing the amount of welding ribbon used.

[0007] The above technical problems of the present invention are mainly solved by the following technical solutions: the present invention includes a cell, wherein the front and back of the cell are respectively printed with main grids, and fine grids are printed between the main grids; the number of fine grids on the front of the cell (1) is less than the number of fine grids on the back of the cell; the cell includes a positive electrode as the front electrode and a negative electrode as the front electrode, the two electrode sheets are stacked in sequence and the positive and negative electrodes are placed alternately. On this basis, a photovoltaic module with positive and negative cells placed alternately is designed and invented, which can make it unnecessary to connect the welding strip to the front and back of the cell at the same time, so that the gap between the cell cells can be omitted. The cell includes two types, namely, a positive electrode as the front electrode and a negative electrode as the front electrode. The number of fine grid lines on the front and back patterns of the printed screen is inconsistent to facilitate the distinction between the front and back. The front fine grid lines are fewer, which can ensure that the current inside the cell can be collected by the current while ensuring that the light receiving area of ​​the cell is less affected. The back fine grid lines are more, which can fully ensure the current collection capacity.

[0008] Photovoltaic cells are made using printed meshes. The front and back patterns of the printed screen can print the positive and negative electrodes of the photovoltaic cell at the same time. The number of fine grid lines on the front and back patterns of the printed screen is inconsistent to facilitate the distinction between the front and back. The front side has fewer fine grid lines, which can ensure that the current inside the cell can be collected while also ensuring that the light-receiving area of ​​the cell is less affected. The back side has more fine grid lines, which can fully guarantee the current collection capability.

[0009] The printing screen prints the main grid on the battery cell with the positive electrode facing upwards. After printing is completed, it enters the next process and prints the fine grid (a smaller number) on the battery cell. The battery cell is then sucked by a robotic arm and flipped over. The flipped battery cell faces the negative electrode upwards, and then the main grid is printed on the battery cell. After printing is completed, it enters the next process and prints the fine grid (a larger number) on the battery cell. After completion, the battery undergoes subsequent processes until the complete battery cell production process is completed.

[0010] Afterwards, the main grid is printed on the battery cells with the negative pole facing upwards in another placement mode. After printing, it enters the next process and prints fine grids (a smaller number) on the battery cells. The battery cells are then sucked up by a robotic arm and flipped over. The flipped battery cells face the positive pole upwards, and the main grid is then printed on the battery cells. After printing, it enters the next process and prints fine grids (a larger number) on the battery cells. After completion, the battery undergoes subsequent processes until the complete battery cell production process is completed.

[0011] At this point, the production of two types of battery cells is completed: positive electrode facing up (fewer fine grids), negative electrode facing down (more fine grids), and negative electrode facing up (fewer fine grids), positive electrode facing down (more fine grids).

[0012] Preferably, test electrodes are also included, and the test electrodes are respectively located on the surface of the cell located at the bottom and the surface of the cell located in the middle after placement. After the photovoltaic electrode sheets are placed according to the photovoltaic module structure, a test electrode is set on the surface of the cell located at the bottom and the surface of the cell located in the middle, respectively. The excess carrier concentration and the average photoluminescence value of the bottom area and the middle area are tested and obtained, and the proportionality coefficient is obtained according to the excess carrier concentration and the average photoluminescence value; the average reflectivity of the test electrode setting area to the test light is tested, and the photoluminescence value of the test electrode under a specific luminous flux is tested. The effective carrier lifetime of the bottom area and the middle area can be obtained according to the luminous flux, reflectivity, body doping concentration, photoluminescence value of the test electrode and the proportionality coefficient; at the same time, the bottom area and the middle area are tested and obtained. The composite current density and material body life of the bottom area; that is, according to the thickness of the photoelectric conversion unit, the body doping concentration obtained by the resistivity test of the photoelectric conversion unit, the effective carrier life of the bottom area and the middle area, the surface composite current density of the bottom area and the middle area, the material body life of the bottom area and the middle area, and the photoluminescence value of the test electrode, the composite current density of the metal semiconductor contact between the test electrode and the photoelectric conversion unit can be calculated. The process is simple and does not require metal corrosion, so that a simple and fast metal-semiconductor interface composite current density test is realized, and the test results are true and accurate, which helps to judge the working status of the photovoltaic module.

[0013] Preferably, the outermost layer of the fine grid forms an outer frame of the grid line. A PAD point is designed at one end of each main grid line, and the PAD point is located outside the outer frame of the grid line.

[0014] Preferably, a PAD point is provided at one end of the busbar, and the other end extends directly outward from the outer frame of the grid lines. The PAD point is located outside the outer frame of the grid lines, with the edge of the PAD point 0.3-1 mm from the edge of the cell. The other end of the busbar line extends directly outward from the outer frame of the grid lines, 0.2-0.5 mm from the edge of the cell.

[0015] Preferably, the PAD points on the front and back of the cell are in opposite directions. The front and back main grid PAD positions are staggered, and the main grid extends beyond the outer frame of the thin grid, which can achieve the purpose of better current collection.

[0016] Preferably, the other end of the main grid is directly 0.2mm-0.5mm away from the edge of the battery cell.

[0017] Preferably, the edge of the PAD point is 0.3 mm to 1 mm away from the edge of the battery cell.

[0018] Preferably, solder ribbon is provided between the PAD points of adjacent cells. This effectively utilizes the gap area between cells, while reducing the amount of solder ribbon used, thus achieving cost reduction and efficiency improvement. By reducing the cell width, only a small section of solder ribbon is required to complete the circuit.

[0019] The beneficial effects of the present invention are as follows: by staggered printing of grid lines, the positive and negative electrodes can be on the same plane, and finally at the end of the component manufacturing, adjacent battery cells can be attached to each other without spacing. At the same time, by reducing the width of the battery cells and placing the photovoltaic components of the battery cells alternately with the positive and negative electrodes, the welding ribbon does not need to connect the front and back of the battery cells at the same time, so that the gaps between the battery cells do not need to be retained, thereby achieving the effect of reducing the amount of welding ribbon used. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front structural schematic diagram of the utility model.

[0021] Figure 2 This is a schematic diagram of the back structure of the utility model.

[0022] Figure 3 This is a schematic diagram of a main grid structure of the present utility model.

[0023] Figure 4 This is a schematic diagram of a main grid three-dimensional structure of the present utility model.

[0024] In the figure, 1 is the electrode sheet, 2 is the main grid, 3 is the fine grid, 4 is the welding strip, and 5 is the PAD point. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions of the present invention are further described in detail below through embodiments and in combination with the accompanying drawings. It should be understood that the specific implementation method described here is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Photovoltaic modules play an important role as energy solutions in modernization. Their unique photovoltaic effect can convert light energy into electrical energy. However, with the extreme utilization of the built-in space of photovoltaic modules, the effective illumination area of ​​the gaps between strings and cells is wasted. In today's pursuit of cost reduction and efficiency improvement, in order to reasonably and effectively utilize the module space to maximize power generation, a photovoltaic module with positive and negative cells placed alternately is designed and invented. This allows the welding ribbon to be connected to the front and back of the cell at the same time, so that the gaps between the cell cells do not need to be retained.

[0027] The existing technology connects the positive and negative poles of the battery cell together through welding ribbons to form a path, but the connection method is that the welding ribbon connects the front side of the battery cell to the back side of the battery cell. The battery cells need to be placed in the same polarity and the same direction, so there needs to be a gap between the battery cells to ensure that the welding ribbon passes through, which leads to inevitable space waste in the photovoltaic module.

[0028] At the same time, the existing technology uses a large amount of solder ribbon for connecting battery strings, which is not conducive to cost reduction.

[0029] The purpose of the present invention is to innovate a photovoltaic cell, which can make the positive and negative electrodes on the same plane by staggered printing of grid lines, and finally show that adjacent cells can be attached to each other without any spacing at the end of the component manufacturing.

[0030] At the same time, by reducing the width of the cell, the amount of solder ribbon used can be reduced. Wide cell widths require the solder ribbon to be laid across the entire width of the cell. Otherwise, the current in the center area cannot be collected due to the cell's large area. By reducing the width of the cell, the distance electrons travel within the cell becomes shorter, allowing for better current collection even with a short section of solder ribbon.

[0031] The advantage of the present invention is that it acts on the photovoltaic module end, can better utilize the gap area between the battery cells based on the original technology, and at the same time reduce the amount of welding tape used, so as to achieve the effect of reducing costs and increasing efficiency.

[0032] 1. Reduce the width of the battery cell so that only a small section of solder ribbon is needed to conduct the circuit.

[0033] 2. The main grid PAD positions on the front and back sides are staggered, and the main grid extends beyond the outer frame of the thin grid, which can better collect current.

[0034] 3. The positive and negative electrodes are printed on the same screen at the same time to achieve the effect of a photovoltaic module with no gap.

[0035] Printing: Print the paste on the battery cell through a screen.

[0036] PAD point: an area that can fully form an alloy connection with the soldering ribbon, usually designed in the form of a square or trapezoid. Soldering ribbon: tin-coated copper ribbon, a soldering ribbon with a tin layer coated on the outer surface of the copper base ribbon.

[0037] Flexible carrier film: plays a sealing role, protecting the space between the solder ribbon and the battery cell from being penetrated by the encapsulation film.

[0038] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) therein can be performed in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operations are completed, but can also have additional steps not included in the figures; the process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0039] The technical solution of the present invention will be further specifically described below with reference to embodiments and in conjunction with the accompanying drawings.

[0040] Embodiment: A photovoltaic cell without spacing in this embodiment, such as Figure 1 、 Figure 2 As shown, it includes a cell 1, with main grids 2 printed on the front and back of each cell, and fine grids 3 printed between the main grids 2. The number of fine grids 3 on the front of the cell 1 is less than the number of fine grids 3 on the back. By staggering the grid lines, the positive and negative electrodes can be on the same plane. Finally, in the finished component, adjacent cells can be attached without any gaps. At the same time, by reducing the width of the cell, the soldering ribbon does not need to connect the front and back of the cell at the same time, so there is no need to maintain gaps between the cells, achieving the effect of reducing the amount of soldering ribbon used.

[0041] Photovoltaic cells are made using printed meshes. The front and back patterns of the printed screen can print the positive and negative electrodes of the photovoltaic cell at the same time. The number of fine grid lines on the front and back patterns of the printed screen is inconsistent to facilitate the distinction between the front and back. The front side has fewer fine grid lines, which can ensure that the current inside the cell can be collected while also ensuring that the light-receiving area of ​​the cell is less affected. The back side has more fine grid lines, which can fully guarantee the current collection capability.

[0042] The printing screen prints the main grid on the battery cell with the positive electrode facing upwards. After printing is completed, it enters the next process and prints the fine grid (a smaller number) on the battery cell. The battery cell is then sucked by a robotic arm and flipped over. The flipped battery cell faces the negative electrode upwards, and then the main grid is printed on the battery cell. After printing is completed, it enters the next process and prints the fine grid (a larger number) on the battery cell. After completion, the battery undergoes subsequent processes until the complete battery cell production process is completed.

[0043] Afterwards, the main grid is printed on the battery cells with the negative pole facing upwards in another placement mode. After printing, it enters the next process and prints fine grids (a smaller number) on the battery cells. The battery cells are then sucked up by a robotic arm and flipped over. The flipped battery cells face the positive pole upwards, and the main grid is then printed on the battery cells. After printing, it enters the next process and prints fine grids (a larger number) on the battery cells. After completion, the battery undergoes subsequent processes until the complete battery cell production process is completed.

[0044] At this point, the production of two types of battery cells is completed: positive electrode facing up (fewer fine grids), negative electrode facing down (more fine grids), and negative electrode facing up (fewer fine grids), positive electrode facing down (more fine grids).

[0045] The battery cell 1 includes two types, namely, a positive electrode as the front electrode cell and a negative electrode as the front electrode cell. Figure 3 、 Figure 4 As shown in the figure, the number of fine grid lines on the front and back of the printed screen is inconsistent, which makes it easier to distinguish the front and back. There are fewer fine grid lines on the front side, which can ensure that the current inside the battery cell can be collected by the current while also ensuring that the light-receiving area of ​​the battery cell is less affected. There are more fine grid lines on the back side, which can fully guarantee the current collection capability.

[0046] The outermost fine grid 3 constitutes the outer frame of the grid line. A PAD point is designed at one end of each main grid line, and the PAD point is located outside the outer frame of the grid line. A PAD point 5 is provided at one end of the main grid 2, and the edge of the PAD point 5 is 0.3mm-1mm away from the edge of the battery cell 1, and the other end extends straight out of the outer frame of the grid line. The other end of the main grid 2 is 0.2mm-0.5mm away from the edge of the battery cell. The PAD point is located outside the outer frame of the grid line, and the edge of the PAD point is 0.3-1mm away from the edge of the battery cell. The other end of the main grid line extends straight out of the outer frame of the grid line, 0.2-0.5mm away from the edge of the battery cell. The PAD points 5 on the front and back of the battery cell 1 are in opposite directions. The staggered design of the main grid PAD positions on the front and back sides, and the main grid extending out of the fine grid outer frame, can achieve the purpose of better current collection.

[0047] Solder ribbons 4 are placed between the PAD points 5 of adjacent cells 1. This technology effectively utilizes the gaps between cells while reducing the amount of solder ribbon used, achieving cost savings and increased efficiency. By reducing the cell width, only a small section of solder ribbon is needed to complete the circuit.

[0048] Example

[0049] A uniquely designed printing screen and printing process creates a gapless photovoltaic cell. The front and back patterns of the screen can simultaneously print the positive and negative electrodes of the photovoltaic cell. First, the front and back patterns of the screen are designed with several busbars. Each busbar has a pad at one end, located outside the outer border of the busbar. The edge of the pad is 0.3-1mm from the edge of the cell. The other end of the busbar extends directly out of the outer border of the busbar, 0.2-0.5mm from the edge of the cell. The pads on the front and back face opposite directions.

[0050] By staggered printing of grid lines, the positive and negative electrodes can be on the same plane, and finally, at the end of the component manufacturing, adjacent battery cells can be attached to each other without any spacing. At the same time, by reducing the width of the battery cell, the soldering ribbon does not need to connect the front and back of the battery cell at the same time, so that the gap between the battery cells does not need to be retained, achieving the effect of reducing the amount of soldering ribbon used.

[0051] Subsequently: the number of fine grid lines on the front and back of the printed screen is inconsistent to facilitate the distinction between the front and back. There are fewer fine grid lines on the front, which can ensure that the current inside the battery cell can be collected while also ensuring less impact on the light-receiving area of ​​the battery cell. There are more fine grid lines on the back, which can fully guarantee the current collection capability.

[0052] Afterwards, the printing screen is used to print the main grid on the battery cell with the positive electrode facing upward. After printing is completed, the next process is entered to print the fine grid (a smaller number) on the battery cell. The battery cell is then sucked by a robotic arm and flipped over. The flipped battery cell faces the negative electrode upward, and the main grid is then printed on the battery cell. After printing is completed, the next process is entered to print the fine grid (a larger number) on the battery cell. After completion, the battery undergoes subsequent processes until the complete battery cell production process is completed.

[0053] Afterwards, the main grid is printed on the battery cells with the negative pole facing upwards in another placement mode. After printing, it enters the next process and prints fine grids (a smaller number) on the battery cells. The battery cells are then sucked up by a robotic arm and flipped over. The flipped battery cells face the positive pole upwards, and the main grid is then printed on the battery cells. After printing, it enters the next process and prints fine grids (a larger number) on the battery cells. After completion, the battery undergoes subsequent processes until the complete battery cell production process is completed.

[0054] At this point, the production of two types of battery cells is completed: positive electrode facing up (fewer fine grids), negative electrode facing down (more fine grids), and negative electrode facing up (fewer fine grids), positive electrode facing down (more fine grids).

[0055] The present invention uses staggered grid lines to allow the positive and negative electrodes to be on the same plane. This ultimately results in adjacent cells being placed side by side without any spacing. By reducing the cell width, the soldering ribbon no longer needs to connect both the front and back sides of the cells, eliminating the need for gaps between cells and reducing the amount of soldering ribbon used. This has the advantage of being able to better utilize the gaps between cells within the photovoltaic module, while also reducing the amount of soldering ribbon used, ultimately reducing costs and increasing efficiency.

[0056] 1. Reduce the width of the battery cell so that only a small section of solder ribbon is needed to conduct the circuit.

[0057] 2. The main grid PAD positions on the front and back sides are staggered, and the main grid extends beyond the outer frame of the thin grid, which can better collect current.

[0058] 3. The positive and negative electrodes are printed on the same screen at the same time to achieve the effect of a photovoltaic module with no gap.

[0059] The specific embodiments described herein are merely examples of the spirit of the present invention. The above embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that technicians in the technical field to which the present invention belongs can make various modifications or supplements to the described specific embodiments or replace them in a similar manner, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims. For ordinary technicians in this field, multiple variations and improvements can be made without departing from the concept of the present invention. Therefore, the scope of protection of the patent of the present invention should be based on the attached claims.

Claims

1. A photovoltaic cell with no spacing, comprising a cell (1), characterized in that: The front and back sides of the cell (1) are respectively printed with main grids (2), and fine grids (3) are printed between the main grids (2); The number of fine grids (3) on the front side of the cell (1) is lower than the number of fine grids (3) on the back side of the cell (1); The battery sheet (1) comprises an electrode sheet with a positive electrode as the front side and an electrode sheet with a negative electrode as the front side, wherein the two electrode sheets are stacked in sequence and the positive and negative electrodes are placed alternately.

2. The gapless photovoltaic cell according to claim 1, characterized in that: The outermost layer of the fine grid (3) forms the outer frame of the grid line.

3. The gapless photovoltaic cell according to claim 2, characterized in that: One end of the main grid (2) is provided with a PAD point (5), and the other end extends directly out of the outer frame of the grid line.

4. The gapless photovoltaic cell according to claim 3, characterized in that: The PAD points (5) on the front and back sides of the battery cell (1) are in opposite directions.

5. The gapless photovoltaic cell according to claim 1, characterized in that: The other end of the main grid (2) is directly connected to the edge of the battery cell by 0.2 mm to 0.5 mm.

6. The gapless photovoltaic cell according to claim 3 or 4, characterized in that: The edge of the PAD point (5) is 0.3 mm to 1 mm away from the edge of the battery cell (1).

7. The gapless photovoltaic cell according to claim 3 or 4, characterized in that: A welding strip (4) is provided between the PAD points (5) of adjacent battery cells (1).

8. The gapless photovoltaic cell according to claim 1, characterized in that: It also includes test electrodes, which are respectively located on the surface of the battery cell at the bottom and the surface of the battery cell at the middle after placement.

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