Silicon-based heterojunction back contact solar cell and photovoltaic module
By using an alternating electrode design and insulating adhesive for isolation, combined with low-temperature welding wire, the high cost and high-temperature welding problems of back-contact heterojunction solar cells have been solved, achieving a low-cost, low-difficulty production process and a high yield.
Patent Information
- Application Number
- CN202422945467.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Existing back-contact heterojunction solar cells suffer from problems such as large metal paste usage, high production costs, complex processes, and cell breakage due to high-temperature welding.
The design employs alternating first and second electrodes, separated by insulating adhesive, and combined with low-temperature welding wire welding, simplifying the production process and avoiding breakage during high-temperature welding.
This achieves lower electrode slurry usage, reduces production costs, simplifies the process, increases yield, and avoids cell breakage.
Smart Images
Figure CN223503326U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of solar cell module technology, specifically relating to a silicon-based heterojunction back contact solar cell and photovoltaic module. Background Technology
[0002] Traditional solar cells interconnect the front and rear electrodes using welding wires. This results in significant gaps between adjacent cells, reducing the effective area. Furthermore, the edges of the cells and the junctions with the welding wires are prone to physical damage, increasing the risk of product defects. Therefore, with the continuous development of solar cell technology, back-contact heterojunction solar cells are receiving increasing attention from the industry. Back-contact heterojunction solar cells have no metal electrodes blocking the front, eliminating the problem of light loss due to front electrode shading and allowing for the reception of more sunlight. The back requires printed metal electrodes to meet the requirements of interconnecting crystalline silicon solar cells during subsequent photovoltaic module manufacturing. Moreover, the silicon substrate surface is passivated with intrinsic amorphous silicon, reducing surface recombination and improving open-circuit voltage, making it a highly efficient solar cell technology.
[0003] The electrodes of existing back-contact heterojunction solar cells are usually composed of mutually perpendicular main grids and sub-grids, which results in problems such as large metal paste consumption and high production costs.
[0004] Furthermore, back-contact heterojunction solar cells use conductive backsheets or solder strips to interconnect electrodes on one side. The conductive backsheet connection method requires a custom backsheet and conductive adhesive, which increases material costs and makes the process more difficult. The solder strip welding method used for back contacts cannot be performed using traditional string welding machines, and it requires the laying of some insulating layers. Moreover, the stress generated during high-temperature welding causes the cell to bend, affecting the process breakage rate and increasing the process difficulty and cost. Utility Model Content
[0005] The purpose of this invention is to provide a silicon-based heterojunction back-contact solar cell and photovoltaic module with low production cost and simple manufacturing process.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0007] This invention provides a silicon-based heterojunction back-contact solar cell, comprising multiple silicon-based heterojunction back-contact solar cell wafers and multiple welding wires connecting the multiple silicon-based heterojunction back-contact solar cell wafers; wherein each silicon-based heterojunction back-contact solar cell wafer comprises a cell body, multiple first electrodes and multiple second electrodes arranged side-by-side and alternately distributed on the back surface of the cell body, multiple first insulating adhesives disposed on the multiple first electrodes, and multiple second insulating adhesives disposed on the multiple second electrodes; wherein the first electrodes and the second electrodes extend along the length direction of the cell body; multiple first insulating adhesives are disposed along the length direction of each first electrode, and multiple second insulating adhesives are disposed along the length direction of each second electrode, and the first insulating adhesives and the second insulating adhesives are alternately distributed along the length direction of the cell body; the multiple welding wires are respectively welded to the first electrodes or the second electrodes, and the multiple welding wires are respectively in contact with the first insulating adhesives or the second insulating adhesives.
[0008] According to one specific embodiment, the solar cell body includes an N-type silicon wafer substrate, a first amorphous silicon passivation film formed on the front side of the N-type silicon wafer substrate, a silicon nitride antireflection film formed on the first amorphous silicon passivation film, a second amorphous silicon passivation film formed on the back side of the N-type silicon wafer substrate, a doped microcrystalline silicon film formed on the second amorphous silicon passivation film, and a transparent conductive film formed on the doped microcrystalline silicon film; the doped microcrystalline silicon film includes n-type doped layers and p-type doped layers alternately distributed along the width direction of the solar cell body; the plurality of first electrodes and the plurality of second electrodes are respectively formed on the transparent conductive film, and each n-type doped layer corresponds to one first electrode, and each p-type doped layer corresponds to one second electrode.
[0009] Furthermore, the transparent conductive film is made of indium tin oxide.
[0010] Furthermore, the thickness of the N-type silicon substrate is 90 micrometers to 130 micrometers; the thickness of the first amorphous silicon passivation film is 3 nanometers to 10 nanometers; the thickness of the silicon nitride antireflective film is 80 nanometers to 100 nanometers; the thickness of the second amorphous silicon passivation film is 3 nanometers to 10 nanometers; the thickness of the doped microcrystalline silicon film is 15 nanometers to 25 nanometers; and the thickness of the transparent conductive film is 15 nanometers to 25 nanometers.
[0011] Furthermore, the widths of the n-type doped layer and the p-type doped layer are 0.7 mm to 1.5 mm, respectively.
[0012] According to some specific embodiments, both the first electrode and the second electrode are formed by curing low-temperature silver paste or low-temperature silver-coated copper paste.
[0013] According to some specific embodiments, the width of the first electrode and the second electrode is 15 micrometers to 30 micrometers, and the two ends of the first electrode and the two ends of the second electrode are respectively 0.3 mm to 1 mm away from the edge of the battery cell body.
[0014] According to some specific embodiments, the total number of first and second electrodes on each silicon-based heterojunction back contact solar cell is 50 to 120, and the first and second electrodes are distributed at equal intervals on the cell body.
[0015] According to some specific embodiments, the length of each first insulating adhesive and each second insulating adhesive is 0.8 mm to 1.2 mm, and the width is 0.5 mm to 0.7 mm; in the length direction of the battery cell body, the distance between any two adjacent first insulating adhesives and second insulating adhesives is equal; arranged in a column perpendicular to the first electrode and the second electrode, there are a total of 10 to 32 columns of first insulating adhesives and second insulating adhesives.
[0016] This invention also provides a photovoltaic module, which includes the aforementioned silicon-based heterojunction back-contact solar cell.
[0017] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:
[0018] The electrode design of this invention eliminates the main grid lines perpendicular to the fine grid and differs from the finger-shaped electrode morphology of traditional back-contact batteries, enabling lower electrode paste usage and better current collection. The use of insulating adhesive in this invention effectively isolates the positive and negative electrodes, allowing for separate welding of the positive and negative electrodes during module assembly, preventing short circuits and simplifying the production process. This invention utilizes welding wire, a simple, low-cost, and low-process welding method that also avoids cell breakage caused by high-temperature welding, thus improving yield. Attached Figure Description
[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the cross-section of a monolithic silicon-based heterojunction back-contact solar cell.
[0021] Figure 2 This is a front view of a monolithic silicon-based heterojunction back-contact solar cell.
[0022] Figure 3 This is a back view of a monolithic silicon-based heterojunction back contact solar cell with only the first electrode 2 and the second electrode 3 printed on it.
[0023] Figure 4 This is a back view of the monolithic silicon-based heterojunction back-contact solar cell of this utility model.
[0024] In the above figures, 1 is the battery cell body; 2 is the first electrode; 3 is the second electrode; 4 is the first insulating adhesive; 5 is the second insulating adhesive; 11 is the N-type silicon wafer substrate; 12 is the first amorphous silicon passivation film; 13 is the silicon nitride antireflection film; 14 is the second amorphous silicon passivation film; 15 is the doped microcrystalline silicon film; and 16 is the transparent conductive film. Detailed Implementation
[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0026] In the description of this utility model, it should be understood that the front side refers to the side of the solar cell facing the sun, and the back side refers to the side of the solar cell facing away from the sun, that is, the side opposite to the front side; wherein, the attached... Figure 1 The top is the front, and the bottom is the back. The above description of directional terms is only for the convenience of describing the embodiments of this utility model and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this utility model.
[0027] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model according to the specific circumstances.
[0028] Unless otherwise specified, all components of this invention can be manufactured using materials conventionally used in the field. All raw materials used in this invention are existing materials and can be provided by suppliers.
[0029] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0030] This utility model relates to a silicon-based heterojunction back-contact solar cell, and a photovoltaic module made using the silicon-based heterojunction back-contact solar cell.
[0031] A silicon-based heterojunction back-contact solar cell includes multiple silicon-based heterojunction back-contact solar cell sheets and multiple welding wires connecting the multiple silicon-based heterojunction back-contact solar cell sheets.
[0032] The structure of each silicon-based heterojunction back-contact solar cell is largely the same. The following is an introduction using a silicon-based heterojunction back-contact solar cell as an example.
[0033] Figure 1 The cross-section of a monolithic silicon-based heterojunction back-contact solar cell is shown. Figure 2 The front side of a monolithic silicon-based heterojunction back-contact solar cell is shown, from... Figure 2 It is evident that there are no metal electrodes on its front side. Figure 3 The back side of a monolithic silicon-based heterojunction back-contact solar cell with only the first electrode 2 and the second electrode 3 printed on it is shown. Figure 4 The back side of the monolithic silicon-based heterojunction back-contact solar cell of this invention is shown.
[0034] like Figure 4 As shown, a silicon-based heterojunction back-contact solar cell includes a cell body 1, a plurality of first electrodes 2 and a plurality of second electrodes 3 arranged side-by-side and alternately distributed on the back surface of the cell body 1, a plurality of first insulating adhesives 4 disposed on the plurality of first electrodes 2, and a plurality of second insulating adhesives 5 disposed on the plurality of second electrodes 3. The alternating distribution of the plurality of first electrodes 2 and the plurality of second electrodes 3 means that the first electrodes 2 and the second electrodes 3 are separated from each other and do not contact each other, and the first electrode 2 in the middle is flanked by the second electrodes 3, and the first electrodes 2 are flanked by the second electrodes 3. That is, as... Figure 3 and Figure 4 As shown, from top to bottom, the first electrode 2, the second electrode 3, the first electrode 2, the second electrode 3, the first electrode 2, the second electrode 3, and so on are distributed sequentially.
[0035] like Figure 3 As shown, both the first electrode 2 and the second electrode 3 extend along the length of the battery cell body 1. The first electrode 2 and the second electrode 3 are parallel to each other and equally spaced, meaning that the distance between any two adjacent first electrodes 2 and second electrodes 3 is equal. Both the first electrode 2 and the second electrode 3 are straight segments. The width of the first electrode 2 and the second electrode 3 is 15 micrometers to 30 micrometers. The two ends of the first electrode 2 (i.e., Figure 3 The left and right ends of the first electrode) and the two ends of the second electrode 3 (i.e. Figure 3The left and right ends of the electrode are respectively 0.3 mm to 1 mm away from the edge of the cell body 1 (specifically, the N-type silicon substrate 11). The total number of the first electrode 2 and the second electrode 3 on the silicon-based heterojunction back contact solar cell is 50 to 120.
[0036] According to one embodiment, both the first electrode 2 and the second electrode 3 are formed by curing low-temperature silver paste or low-temperature silver-coated copper paste. The curing method is a conventional method in the art, such as curing at 220°C for 5 to 10 minutes.
[0037] like Figure 4 As shown, multiple first insulating adhesives 4 are disposed along the length of each first electrode 2, and multiple second insulating adhesives 5 are disposed along the length of each second electrode 3. The length of each first insulating adhesive 4 and each second insulating adhesive 5 is 0.8 mm to 1.2 mm (e.g., 1 mm), and the width is 0.5 mm to 0.7 mm (e.g., 0.6 mm). Along the length of the cell body 1, the first insulating adhesives 4 and second insulating adhesives 5 are alternately distributed, and the distance between any two adjacent first insulating adhesives 4 and second insulating adhesives 5 is equal. Insulating adhesives aligned perpendicular to the direction of the first electrode 2 and the second electrode 3 (i.e., the width direction of the cell body 1) form a row, and there are a total of 10 to 32 rows of first insulating adhesives 4 and second insulating adhesives 5. That is, as shown... Figure 4 As shown, from left to right, there are rows of first insulating adhesive 4, rows of second insulating adhesive 5, rows of first insulating adhesive 4, rows of second insulating adhesive 5, rows of first insulating adhesive 4, rows of second insulating adhesive 5, and so on.
[0038] Multiple welding wires are used to connect two silicon-based heterojunction back-contact solar cells, respectively welding them to either the first electrode 2 or the second electrode 3. Furthermore, each welding wire is in contact with either the first insulating adhesive 4 or the second insulating adhesive 5. Specifically, the welding wires are arranged as follows: the welding wires welded to the first electrode 2 are laid vertically on the first electrode 2 and the second insulating adhesive 5, and laminated at a high temperature of approximately 140–150°C to achieve welding between the first electrode 2 and the welding wires; similarly, the welding wires welded to the second electrode 3 are laid vertically on the second electrode 3 and the first insulating adhesive 4, and laminated at approximately 140–150°C to achieve welding between the second electrode 3 and the welding wires. This welding method is simple, low-cost, and has low process difficulty. It also avoids cell breakage caused by high-temperature welding, thus improving the yield rate.
[0039] like Figure 1As shown, the solar cell body 1 includes an N-type silicon substrate 11, a first amorphous silicon passivation film 12 formed on the front side of the N-type silicon substrate 11, a silicon nitride antireflective film 13 formed on the first amorphous silicon passivation film 12, a second amorphous silicon passivation film 14 formed on the back side of the N-type silicon substrate 11, a doped microcrystalline silicon film 15 formed on the second amorphous silicon passivation film 14, and a transparent conductive film 16 formed on the doped microcrystalline silicon film 15. The transparent conductive film 16 is made of tin-doped indium oxide (TCO).
[0040] The doped microcrystalline silicon thin film 15 includes alternating n-type and p-type doped layers along the width direction of the cell body 1, i.e., n-type doped layers are flanked by p-type doped layers, and p-type doped layers are flanked by n-type doped layers. The total number of n-type and p-type doped layers is equal to the total number of first electrodes 2 and second electrodes 3, and the extension directions of the n-type and p-type doped layers are consistent with the extension directions of the first electrodes 2 and second electrodes 3. Multiple first electrodes 2 and multiple second electrodes 3 are respectively formed on a transparent conductive thin film 16, with one first electrode 2 corresponding to each n-type doped layer and one second electrode 3 corresponding to each p-type doped layer. That is, one first electrode 2 is in contact with a transparent conductive thin film 16 outside an n-type doped layer, and one second electrode 3 is in contact with a transparent conductive thin film 16 outside a p-type doped layer.
[0041] The length and width of the N-type silicon substrate 11 can be arbitrary, such as 210mm × 105mm or 182mm × 105mm. The thickness of the N-type silicon substrate 11 is 90 micrometers to 130 micrometers; the thickness of the first amorphous silicon passivation film 12 is 3 nanometers to 10 nanometers; the thickness of the silicon nitride antireflection film 13 is 80 nanometers to 100 nanometers; the thickness of the second amorphous silicon passivation film 14 is 3 nanometers to 10 nanometers; the thickness of the doped microcrystalline silicon film 15 is 15 nanometers to 25 nanometers; and the thickness of the transparent conductive film 16 is 15 nanometers to 25 nanometers. The n-type doped layer (in-TCO) and the p-type doped layer (ip-TCO) are straight segments with a width of 0.7 mm to 1.5 mm, and the two ends of the straight segments are 0 to 0.2 mm away from the edge of the N-type silicon substrate 11.
[0042] The electrode design of this invention eliminates the main grid lines perpendicular to the fine grid and differs from the finger-shaped electrode morphology of traditional back-contact batteries, enabling lower electrode paste usage and better current collection. The use of insulating adhesive in this invention effectively isolates the positive and negative electrodes, allowing for separate welding of the positive and negative electrodes during module assembly, preventing short circuits and simplifying the production process. This invention utilizes welding wire, a simple, low-cost, and low-process welding method that also avoids cell breakage caused by high-temperature welding, thus improving yield.
[0043] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A silicon-based heterojunction back-contact solar cell, characterized in that: The system includes multiple silicon-based heterojunction back-contact solar cells and multiple welding wires connecting the multiple silicon-based heterojunction back-contact solar cells; wherein each silicon-based heterojunction back-contact solar cell includes a cell body (1), multiple first electrodes (2) and multiple second electrodes (3) arranged side by side and alternately distributed on the back surface of the cell body (1), multiple first insulating adhesives (4) disposed on the multiple first electrodes (2), and multiple second insulating adhesives (5) disposed on the multiple second electrodes (3); wherein the first electrodes (2) and the second electrodes (3) All extend along the length direction of the battery cell body (1); multiple first insulating adhesives (4) are provided in the length direction of each first electrode (2), multiple second insulating adhesives (5) are provided in the length direction of each second electrode (3), and the first insulating adhesives (4) and the second insulating adhesives (5) are alternately distributed in the length direction of the battery cell body (1); multiple welding wires are respectively welded to the first electrode (2) or the second electrode (3), and multiple welding wires are respectively in contact with the first insulating adhesive (4) or the second insulating adhesive (5).
2. The silicon-based heterojunction back-contact solar cell according to claim 1, characterized in that: The cell body (1) includes an N-type silicon substrate (11), a first amorphous silicon passivation film (12) formed on the front side of the N-type silicon substrate (11), a silicon nitride antireflection film (13) formed on the first amorphous silicon passivation film (12), a second amorphous silicon passivation film (14) formed on the back side of the N-type silicon substrate (11), a doped microcrystalline silicon film (15) formed on the second amorphous silicon passivation film (14), and a transparent conductive film (16) formed on the doped microcrystalline silicon film (15). The doped microcrystalline silicon film (15) includes n-type doped layers and p-type doped layers that are alternately distributed along the width direction of the cell body (1). The plurality of first electrodes (2) and the plurality of second electrodes (3) are respectively formed on the transparent conductive film (16), and each n-type doped layer corresponds to one first electrode (2), and each p-type doped layer corresponds to one second electrode (3).
3. The silicon-based heterojunction back-contact solar cell according to claim 2, characterized in that: The transparent conductive film (16) is made of indium tin oxide.
4. The silicon-based heterojunction back-contact solar cell according to claim 2, characterized in that: The thickness of the N-type silicon substrate (11) is 90 micrometers to 130 micrometers; the thickness of the first amorphous silicon passivation film (12) is 3 nanometers to 10 nanometers; the thickness of the silicon nitride antireflection film (13) is 80 nanometers to 100 nanometers; the thickness of the second amorphous silicon passivation film (14) is 3 nanometers to 10 nanometers; the thickness of the doped microcrystalline silicon film (15) is 15 nanometers to 25 nanometers; and the thickness of the transparent conductive film (16) is 15 nanometers to 25 nanometers.
5. The silicon-based heterojunction back-contact solar cell according to claim 2, characterized in that: The widths of the n-type doped layer and the p-type doped layer are 0.7 mm to 1.5 mm, respectively.
6. The silicon-based heterojunction back-contact solar cell according to claim 1, characterized in that: Both the first electrode (2) and the second electrode (3) are formed by curing low-temperature silver paste or low-temperature silver-coated copper paste.
7. The silicon-based heterojunction back-contact solar cell according to claim 1, characterized in that: The width of the first electrode (2) and the second electrode (3) is 15 micrometers to 30 micrometers, and the two ends of the first electrode (2) and the two ends of the second electrode (3) are respectively 0.3 mm to 1 mm away from the edge of the battery cell body (1).
8. The silicon-based heterojunction back-contact solar cell according to claim 1, characterized in that: The total number of first electrodes (2) and second electrodes (3) on each silicon-based heterojunction back contact solar cell is 50 to 120, and the first electrodes (2) and second electrodes (3) are evenly distributed on the cell body (1).
9. The silicon-based heterojunction back-contact solar cell according to claim 1, characterized in that: The length of each first insulating adhesive (4) and each second insulating adhesive (5) is 0.8 mm to 1.2 mm, and the width is 0.5 mm to 0.7 mm, respectively; in the length direction of the battery cell body (1), the distance between any two adjacent first insulating adhesives (4) and second insulating adhesives (5) is equal; in the direction perpendicular to the first electrode (2) and the second electrode (3), there are a total of 10 to 32 rows of first insulating adhesives (4) and second insulating adhesives (5).
10. A photovoltaic module, characterized in that: It includes the silicon-based heterojunction back-contact solar cell according to any one of claims 1 to 9.