Large solar cells, heterojunction solar cells, shingled modules and manufacturing methods

Abstract

This invention relates to a large solar cell sheet, a heterojunction solar cell, a shingled module, and a manufacturing method. The top surface of the junction of each unit in the large solar cell sheet is divided into a cutting area, a top surface bonding area, and a top surface conductive contact area. The cutting area is configured to allow the large solar cell sheet to be cut along it; the top surface bonding area and the top surface conductive contact area are alternately arranged, forming an overlapping edge of the solar cell. After the large solar cell sheet is split, the top surface conductive contact area can directly contact the bottom surface of another heterojunction solar cell to achieve conductive connection. The large solar cell sheet provided by this invention facilitates the splitting operation and provides dedicated bonding and conductive contact areas for each individual solar cell. This design optimizes the production process and performance of heterojunction solar cells.

Description

Technical Field

[0001] This invention relates to the field of energy, and more particularly to a large solar cell, a heterojunction solar cell, a shingled module, and a manufacturing method thereof. Background Technology

[0002] With the accelerating depletion of conventional fossil fuels such as coal, oil, and natural gas globally, the ecological environment is deteriorating, particularly due to increasingly severe global climate change caused by greenhouse gas emissions, posing a serious threat to the sustainable development of human society. Countries around the world have formulated their own energy development strategies to address the finite nature of conventional fossil fuel resources and the environmental problems arising from their development and utilization. Solar energy, with its reliability, safety, widespread availability, longevity, environmental friendliness, and abundant resources, has become one of the most important renewable energy sources and is expected to become a major pillar of future global electricity supply.

[0003] In the new round of energy transformation, my country's photovoltaic (PV) industry has grown into a strategic emerging industry with international competitive advantages. However, the development of the PV industry still faces many problems and challenges. Conversion efficiency and reliability are the biggest technical obstacles restricting the development of the PV industry, while cost control and economies of scale pose economic constraints. As the core component of PV power generation, improving the conversion efficiency of PV modules and developing high-efficiency modules is an inevitable trend. Currently, various high-efficiency modules are emerging on the market, such as shingled, half-cell, multi-busbar, and bifacial modules. As the application sites and regions of PV modules become more and more widespread, the requirements for their reliability are becoming increasingly stringent, especially in areas with severe or extreme weather conditions where high-efficiency and high-reliability PV modules are needed.

[0004] Against the backdrop of vigorously promoting and using solar green energy, shingled modules utilize the electrical principle of low current and low loss (the power loss of a photovoltaic module is directly proportional to the square of the operating current), thus significantly reducing module power loss. Secondly, by fully utilizing the spacing between cells within the module for power generation, it achieves high energy density per unit area. Furthermore, it uses a conductive adhesive with elastomer properties to replace the conventional photovoltaic metal solder ribbon. Because photovoltaic metal solder ribbon exhibits higher series resistance within the entire cell, while the current loop of the conductive adhesive is much shorter than that of the solder ribbon method, shingled modules ultimately become high-efficiency modules. At the same time, their reliability in outdoor applications is superior to conventional photovoltaic modules because shingled modules avoid stress damage to cell-to-cell interconnection points and other current-carrying areas caused by metal solder ribbon. Especially in dynamic environments with alternating high and low temperatures (due to natural loads such as wind and snow), the failure probability of conventional modules using metal solder ribbon interconnection is far higher than that of shingled modules using elastomer-based conductive adhesive interconnection of small crystalline silicon cell wafers.

[0005] The current mainstream process for shingled solar modules uses conductive adhesives to interconnect the cut solar cells. The conductive adhesive mainly consists of a conductive phase and a binder phase. The conductive phase is primarily composed of precious metals, such as pure silver particles or silver-coated copper, nickel, or glass particles, used to conduct electricity between the solar cells. The particle shape and distribution are designed to optimize electrical conductivity; currently, sheet-like or near-spherical combinations of silver powder with a D50 < 10µm are most commonly used. The binder phase mainly consists of weather-resistant polymer resins, typically selected based on bonding strength and weather resistance stability, such as acrylic resin, silicone resin, epoxy resin, or polyurethane. To achieve low contact resistance, low volume resistivity, high adhesion, and long-term excellent weather resistance, conductive adhesive manufacturers design specific formulations for both the conductive and binder phases. This ensures the stability of the shingled module's performance during initial environmental corrosion testing and long-term outdoor applications.

[0006] For battery components connected via conductive adhesive, after encapsulation, they are subject to environmental corrosion during outdoor use. For example, alternating high and low temperatures and thermal expansion and contraction cause relative displacement between the conductive adhesive particles. The most serious consequence is intermittent current connection or even open circuit, primarily due to weak inter-material bonding. This weak bonding is mainly manifested in the fact that the conductive adhesive application process requires a specific operational window, which is relatively narrow in actual production and highly susceptible to environmental factors. These factors, such as the temperature and humidity of the work environment and the duration of exposure to air after application, can cause the conductive adhesive to lose its activity. Furthermore, uneven application and missing parts are easily caused by variations in the adhesive's properties during dispensing, spraying, or printing processes, posing a significant threat to product reliability. Secondly, conductive adhesives are mainly composed of polymer resins and a large amount of precious metal powder, resulting in high costs and some environmental damage (the production and processing of precious metals cause significant pollution). Thirdly, conductive adhesives are paste-like substances with a certain degree of fluidity during application or stacking, making them prone to overflow and causing short circuits between the positive and negative terminals of the shingled interconnect battery strings.

[0007] In other words, most shingled modules made using conductive adhesive bonding have problems such as weak interconnection strength, high environmental requirements for the manufacturing process, easy glue overflow and short circuits during the process, high cost, and low production efficiency.

[0008] Furthermore, in order to achieve conductive connections between individual heterojunction solar cells, electrodes are usually required on the surface of the heterojunction solar cells. These electrodes are made of expensive metals, which is why heterojunction solar cells are typically expensive.

[0009] In the manufacture of heterojunction solar cells, there are currently no large-scale solar cell sheets that can form heterojunction solar cells as described above and are easy to cleave.

[0010] Therefore, there is a need to provide a large solar cell, a heterojunction solar cell, a shingled module, and a manufacturing method to at least partially solve the above problems. Summary of the Invention

[0011] The purpose of this invention is to provide a large solar cell sheet, a heterojunction solar cell, a shingled module, and a manufacturing method. The large solar cell sheet provided by this invention facilitates the dicing process, and is provided with conductive contact areas for achieving conductive connections between the diced heterojunction solar cells and bonding areas for applying adhesives. This design optimizes the production process and performance of the heterojunction solar cell.

[0012] Furthermore, the heterojunction solar cells formed by splitting can achieve conductive connection through direct contact between the light-transmitting conductive film and the sub-grid lines, thus allowing the use of non-conductive adhesives for fixation. This has at least the following advantages:

[0013] First, the good conductivity of the light-transmitting conductive film can optimize the performance of shingled modules and also eliminate the need for electrodes to reduce costs.

[0014] Second, the adhesive may be non-conductive, so factors that easily damage the conductive adhesive, such as environmental corrosion, high and low temperature alternation, and thermal expansion and contraction, will not affect the shingled assembly of the present invention. The shingled assembly is less prone to current connection failure and open circuit, and problems such as open circuit of positive and negative terminals of battery string caused by conductive adhesive overflow will not occur.

[0015] According to one aspect of the present invention, a large solar cell sheet is provided for splitting to form multiple heterojunction solar cells, wherein the multiple heterojunction solar cells can be arranged in a shingled manner to form a cell string.

[0016] The large battery cell includes a substrate sheet, which comprises a central layer and light-transmitting conductive films disposed on the top and bottom surfaces of the central layer. The large battery cell is divided into multiple units arranged along a first direction, with any two adjacent units forming a first unit and a second unit. When the large battery cell is split into smaller pieces, the first unit forms a first battery cell, and the second unit forms a second battery cell.

[0017] The top surface of the boundary between the first unit and the second unit is divided into:

[0018] A cutting region extending in a direction perpendicular to the first direction, the cutting region being configured to allow the large battery cell to be cut along it; and

[0019] The top surface bonding area and the top surface conductive contact area are disposed on one side of the cutting area, and the top surface bonding area and the top surface conductive contact area are alternately arranged in a direction perpendicular to the first direction. The cutting area and the top surface conductive contact area form an overlapping edge of the second battery cell.

[0020] The top surface bonding area and the top surface conductive contact area are configured such that when the second cell is located in the cell string, an adhesive can be applied to the top surface of the top surface bonding area to fix it to the bottom surface of the adjacent heterojunction solar cell, and the top surface conductive contact area can directly contact the bottom surface of the adjacent heterojunction solar cell to achieve conductive connection.

[0021] In one embodiment, sub-grid lines are provided on the top and / or bottom surfaces of the substrate sheet of the large battery cell. When multiple heterojunction solar cells formed by splitting the large battery cell are arranged into a battery string, the sub-grid lines of one of any two adjacent heterojunction solar cells can directly contact the transparent conductive film of the other to achieve conductive connection.

[0022] In one embodiment, a sub-grid line is provided on the top surface of the substrate sheet of the large battery cell, and the sub-grid line extends into the conductive contact area of ​​the top surface.

[0023] In one embodiment, a sub-grid line is provided on the top surface of the substrate sheet of the large battery cell, and there is no sub-grid line in the conductive contact area of ​​the top surface.

[0024] In one embodiment, sub-grid lines are provided on both the top and bottom surfaces of the substrate sheet of the large solar cell, and the sub-grid lines are configured such that in a cell string composed of heterojunction solar cells formed by splitting the cells, the sub-grid lines on the areas facing each other of any two heterojunction solar cells are staggered so as not to contact each other.

[0025] In one embodiment, a bottom surface bonding area and a bottom surface conductive contact area are further provided on the bottom surface of the junction of the first unit and the second unit. The bottom surface bonding area and the bottom surface conductive contact area are located on the other side of the cutting area in the first direction and are alternately arranged in a direction perpendicular to the first direction. The bottom surface bonding area and the bottom surface conductive contact area form an overlapping edge of the first battery cell.

[0026] In one embodiment, each of the subgate lines extends along the first direction, but each subgate line in the bottom surface conductive contact area is not collinear with any other subgate lines on the bottom surface of the substrate.

[0027] In one embodiment, each of the units has a conductive strip on its bottom surface that separates the bottom surface bonding area, the bottom surface conductive contact area, and other areas of the bottom surface, wherein the sub-gate lines on the other areas of the bottom surface and the sub-gate lines on the bottom surface conductive contact area are in contact.

[0028] In one embodiment, the light-transmitting conductive film extends across the entire top and bottom surfaces of the central layer.

[0029] In one embodiment, the transparent conductive film is not present at the top surface bonding area and the bottom surface bonding area.

[0030] In one embodiment, the top surface of the junction between the first unit and the second unit at the foremost end of the large battery cell is further provided with another set of top surface bonding areas and top surface conductive contact areas. The other set of top surface bonding areas and top surface conductive contact areas are located on the other side of the cutting area, and the other set of top surface bonding areas and top surface conductive contact areas form an overlapping edge of the first battery cell.

[0031] In one embodiment, the substrate sheet of the large battery cell does not have main busbars.

[0032] In one embodiment, the central layer includes a silicon wafer, a top-side intrinsic amorphous silicon film disposed on the top surface of the silicon wafer, a P-type amorphous silicon film disposed on the top surface of the top-side intrinsic amorphous silicon film, a bottom-side intrinsic amorphous silicon film disposed on the bottom surface of the silicon wafer, and an N-type amorphous silicon film disposed on the bottom surface of the bottom-side intrinsic amorphous silicon film.

[0033] According to a second aspect of the present invention, a heterojunction solar cell is provided, the heterojunction solar cell being formed by splitting a large sheet of solar cell according to any one of the above embodiments.

[0034] In one embodiment, the light-transmitting conductive film extends across the entire top and bottom surfaces of the central layer, and the light-transmitting conductive film has the same thickness everywhere, such that when an adhesive is applied to the bonding area on the top surface, the adhesive protrudes beyond the light-transmitting conductive film, thereby allowing the light-transmitting conductive film on the opposing surfaces of the two heterojunction solar cells to be separated by the adhesive at the adhesive when the heterojunction solar cell is connected to another heterojunction solar cell.

[0035] In one embodiment, a notch is provided on the top surface bonding area of ​​the light-transmitting conductive film, and when an adhesive is applied to the heterojunction solar cell, the adhesive is located within the notch and does not protrude from the light-transmitting conductive film.

[0036] In one embodiment, sub-grid lines are provided on the top and / or bottom surfaces of the substrate, such that the light-transmitting conductive film of one of the two heterojunction solar cells connected in a shingled manner is in direct contact with the sub-grid lines of the other.

[0037] In one embodiment, the overlapping edge of the heterojunction solar cell that contacts another heterojunction solar cell is provided with a top surface bonding area and a top surface conductive contact area that extend along the overlapping edge and are alternately arranged on the overlapping edge, and a sub-grid line is also present in the top surface conductive contact area, or a sub-grid line is not present in the top surface conductive contact area.

[0038] In one embodiment, a sub-gate line is also present within the top surface conductive contact area, and each sub-gate line in the top surface conductive contact area is not collinear with any sub-gate lines in other areas on the surface where the top surface conductive contact area is located, excluding the top surface conductive contact area itself.

[0039] The heterojunction solar cell has a conductive strip on the surface where the top surface conductive contact area is located, which separates the top surface conductive contact area, the top surface bonding area, and other parts of the surface. The sub-grid lines of the top surface conductive contact area and the sub-grid lines of other parts of the surface are all conductively connected to the conductive strip.

[0040] According to a third aspect of the present invention, a shingled assembly is provided, comprising a battery string, characterized in that the battery string is formed by sequentially connecting multiple heterojunction solar cells according to any one of the above claims in a shingled manner, each of the heterojunction solar cells being fixed to each other by an adhesive, and sub-grid lines being provided on the top surface and / or bottom surface of the heterojunction solar cells, wherein a light-transmitting conductive film of one of two adjacent heterojunction solar cells can directly contact the sub-grid line of the other of the two heterojunction solar cells to achieve a conductive connection between the two adjacent heterojunction solar cells.

[0041] In one embodiment, the adhesive is a non-conductive adhesive.

[0042] In one embodiment, the adhesive is a dot-structured adhesive made of acrylic resin, silicone resin, epoxy resin, or polyurethane.

[0043] In one embodiment, the adhesive is a dotted structure comprising a curing agent, a crosslinking agent, a coupling agent, or rubber balls.

[0044] According to a fourth aspect of the present invention, a manufacturing method is provided for manufacturing shingled components, characterized in that the method comprises the following steps:

[0045] Manufacture a large solar cell sheet according to any one of the above, wherein the large solar cell sheet has sub-busbars;

[0046] Cut along each cutting area of ​​the large solar cell sheet, thereby splitting the large solar cell sheet into multiple heterojunction solar cells;

[0047] Multiple heterojunction solar cells are connected in a shingled manner using a non-conductive adhesive, so that the transparent conductive film of one of two adjacent heterojunction solar cells and the sub-grid line of the other are in direct contact, thereby achieving a conductive connection.

[0048] In one embodiment, the method further includes the step of applying an adhesive to the heterojunction solar cell in one of the following ways: spraying, dripping, rolling, printing, or brushing.

[0049] In one embodiment, the method for manufacturing large solar cells does not include the step of setting main busbars.

[0050] According to the present invention, a large sheet of solar cell for manufacturing heterojunction solar cells can be provided. The connection area of ​​each unit of the large sheet of solar cell has a cutting area, a top surface bonding area, and a top surface conductive contact area. The cutting area facilitates the splitting of the large sheet of solar cell. The top surface bonding area and the top surface conductive contact area form the overlapping edge of a heterojunction solar cell. Multiple heterojunction solar cells formed after the large sheet of solar cell is split can be arranged into a cell string in a shingled manner. In the cell string, the top surface conductive contact area of ​​any two adjacent heterojunction solar cells can contact the other heterojunction solar cell, thereby realizing the contact between the light-transmitting conductive film of one heterojunction solar cell and the sub-grid line of the other to achieve conductive connection. An adhesive for bonding adjacent heterojunction solar cells together can be applied to the top surface bonding area.

[0051] This setup allows for the easy splitting of large solar cells, and the resulting heterojunction solar cells achieve conductive connections through direct contact between the transparent conductive film and the sub-grid lines. This also allows for the use of non-conductive adhesives for fixation, offering at least the following advantages:

[0052] First, the good conductivity of the light-transmitting conductive film can optimize the performance of shingled modules and also eliminate the need for electrodes to reduce costs.

[0053] Second, the adhesive may be non-conductive, so factors that easily damage the conductive adhesive, such as environmental corrosion, high and low temperature alternation, and thermal expansion and contraction, will not affect the shingled assembly of the present invention. The shingled assembly is less prone to current connection failure and open circuit, and problems such as open circuit of positive and negative terminals of battery string caused by conductive adhesive overflow will not occur. Attached Figure Description

[0054] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale.

[0055] Figure 1 A schematic diagram of the top surface of a large battery cell according to a first embodiment of the present invention is shown;

[0056] Figure 2 for Figure 1 A magnified view of part A in the image;

[0057] Figure 3 for Figure 1 A magnified view of part B in the image;

[0058] Figure 4 This is a schematic diagram of the bottom surface of the large battery cell in this embodiment;

[0059] Figure 5 for Figure 4 A magnified view of part C in the image;

[0060] Figure 6A , Figure 6B They are respectively Figure 1 A schematic diagram of the top and bottom surfaces of a single heterojunction solar cell formed by splitting large pieces of solar cells.

[0061] Figure 7 This is a schematic diagram of the top surface of two heterojunction solar cells as shown in Figure 6, arranged in a shingled manner.

[0062] Figure 8 For along Figure 7 A cross-sectional view taken from line AA in the diagram;

[0063] Figure 9 A schematic diagram of the top surface of a large battery cell according to a second embodiment of the present invention;

[0064] Figure 10 for Figure 9 A magnified view of part D in the image;

[0065] Figure 11 for Figure 9 A schematic diagram of the bottom surface of the large solar cell in the image;

[0066] Figure 12 for Figure 11 A magnified view of part E in the image;

[0067] Figure 13 for Figure 9 A schematic diagram of the top surface of two shingled solar cells in a heterojunction solar cell formed by large-scale splitting of the solar cells.

[0068] Figure 14 for Figure 13 A schematic diagram taken along line BB;

[0069] Figure 15 This is a schematic diagram of the top surface of two heterojunction solar cells formed by splitting large pieces of the solar cell according to the third embodiment of the present invention, after they are arranged in a shingled manner.

[0070] Figure 16 For along Figure 15 The cross-sectional view taken from the CC line. Detailed Implementation

[0071] Now, with reference to the accompanying drawings, specific embodiments of the present invention will be described in detail. The embodiments described herein are merely preferred embodiments of the invention; those skilled in the art can conceive of other ways to implement the invention based on these preferred embodiments, and such other ways also fall within the scope of the invention.

[0072] This invention provides a large solar cell, a heterojunction solar cell, and a manufacturing method thereof. Figures 1 to 16 Several preferred embodiments of the large-scale solar cell and heterojunction solar cell of the present invention are shown.

[0073] Figures 1-8 A first embodiment according to the present invention is shown. Figure 1The diagram illustrates a large solar cell 100 in this embodiment, which can be split to form multiple heterojunction solar cells. The large solar cell 100 includes a substrate 11, which includes a central layer and light-transmitting conductive films 13 disposed on the top and bottom surfaces of the central layer. The central layer, for example, includes a silicon wafer, a top-side intrinsic amorphous silicon thin film disposed on the top surface of the silicon wafer, a P-type amorphous silicon thin film disposed on the top surface of the top-side intrinsic amorphous silicon thin film, a bottom-side intrinsic amorphous silicon thin film disposed on the bottom surface of the silicon wafer, and an N-type amorphous silicon thin film disposed on the bottom surface of the bottom-side intrinsic amorphous silicon thin film.

[0074] The large solar cell 100 is divided into multiple units 1 arranged along a straight line. Any two adjacent units 1 are the first unit and the second unit, where the first unit 1a forms the first solar cell and the second unit 1b forms the second solar cell.

[0075] refer to Figure 2 The top surface of the junction 2 between the first unit 1a and the second unit 1b is divided into a cutting area 21, a top surface bonding area 22, and a top surface conductive contact area 23. The cutting area 21 extends in a direction perpendicular to the arrangement direction of the solar cells, and the large solar cell 100 can be split along the cutting area 21. After splitting, the top surface bonding area 22 and the top surface conductive contact area 23 can be formed as the overlapping edge of the second solar cell. The top surface bonding area 22 and the top surface conductive contact area 23 are disposed on one side of the cutting area 21 on the large solar cell 100 and are alternately disposed in a direction parallel to the cutting area 21.

[0076] After the solar cell is split into 100 pieces, the second solar cell can be arranged in a shingled manner with another solar cell (e.g., the first solar cell). The bottom surface of the other solar cell can directly contact the conductive contact area 23 on the top surface of the second solar cell to achieve a conductive connection. Furthermore, the adhesive 9 used to fix the two heterojunction solar cells can be applied to the bonding area 22 on the top surface.

[0077] Sub-grid lines 12 are provided on the top and / or bottom surfaces of the large solar cell 100. In this embodiment, sub-grid lines 12 are provided on both the top and bottom surfaces of the large solar cell 100. When two heterojunction solar cells are arranged in a shingled manner after the solar cell is split, they are electrically connected through direct contact between the sub-grid lines 12 and the light-transmitting conductive film 13.

[0078] Preferably, refer to Figure 2 The sub-grid lines 12 on the top surface of the large cell 100 extend into the conductive contact area 23 on the top surface.

[0079] At the same time, refer to Figure 4 and Figure 5 On the large battery cell 100, a bottom surface bonding area 22a and a bottom surface conductive contact area 23a are further provided on the bottom surface of the junction portion 2 between the first unit 1a and the second unit 1b. The bottom surface bonding area 22a and the bottom surface conductive contact area 23a are located on one side of the cutting area 21, and are alternately arranged in a direction parallel to the cutting area 21. The bottom surface conductive contact area 23a and the bottom surface bonding area 22a together constitute an overlapping edge of the first battery cell. In this embodiment, no sub-grid line 12 is provided in the bottom surface conductive contact area 23a.

[0080] from Figure 2 and Figure 5 As can be seen, the large solar cell 100 is constructed such that: the top surface conductive contact area 23 of the overlapping edge of the top surface of the first solar cell formed by the first unit 1a is provided with a sub-grid line 12, while the bottom surface conductive contact area 23a of the overlapping edge of the bottom surface is not provided with a sub-grid line 12. In this way, when two heterojunction solar cells are arranged in a shingled manner, the top surface conductive contact areas 23 and the bottom surface conductive contact areas 23a of the two heterojunction solar cells facing each other are in contact with each other. At this time, the light-transmitting conductive film 13 of the heterojunction solar cell located on the top side can directly contact the sub-grid line 12 of the heterojunction solar cell located on the bottom side to achieve conductive connection.

[0081] It should be noted that the terms "first unit" and "second unit", "first cell" and "second cell" mentioned in this article are relative descriptions rather than absolute descriptions. For example, the "first unit" in a pair of adjacent units can also be the "second unit" in another pair of adjacent units.

[0082] Next, go to Figure 1 and Figure 3 As can be seen, the pair of first units 1a and second units 1b at the very front of the large battery cell 100 also include another set of top surface bonding areas 22 and top surface conductive contact areas 23. That is, there is a set of top surface bonding areas 22 and top surface conductive contact areas 23 on each side of the cutting area 21. These two sets of top surface bonding areas 22 and top surface conductive contact areas 23 are respectively formed on the top surface of the overlapping edge of the first battery cell and the second battery cell.

[0083] Figure 6A and Figure 6BThis diagram shows the top and bottom surfaces of a single heterojunction solar cell, which is formed by individual units 1 after the large cell sheet 100 is split into individual cells. It can be seen that the top surface of the heterojunction solar cell has alternating top surface bonding areas 22 and top surface conductive contact areas 23 at the edge for overlapping with another heterojunction solar cell, and the top surface conductive contact area 23 contains sub-grid lines 12; the bottom surface of the heterojunction solar cell has alternating bottom surface bonding areas 22a and bottom surface conductive contact areas 23a at the edge for overlapping with another heterojunction solar cell, and the bottom surface conductive contact area 23a does not contain sub-grid lines 12.

[0084] Figure 7 and Figure 8 The structure of two heterojunction solar cells composed of the above-described unit 1 connected in a shingled manner is shown. It can be seen that when the two heterojunction solar cells are connected in a shingled manner, in the area where they are in contact with each other, the sub-grid line 12 of the top surface conductive contact area 23 of one of them and the light-transmitting conductive film 13 of the bottom surface conductive contact area 23a of the other are in direct contact to achieve conductive connection.

[0085] In this embodiment, after the heterojunction solar cells formed by splitting the large cell 100 are arranged in a shingled manner, they are electrically connected by direct contact between the light-transmitting conductive film 13 and the sub-grid line 12. Therefore, the large cell 100 does not need to be provided with a main grid line. This arrangement can save silver paste, reduce costs, and reduce the weight of the heterojunction solar cell.

[0086] Figures 9 to 14 A heterojunction solar cell formed by splitting a large cell sheet 300 according to a second embodiment of the present invention is shown. The structure of each component in this embodiment is similar to that in the previous embodiment, and therefore, the parts that are the same as or similar to those in the previous embodiment will not be described again.

[0087] The large solar cell 300 has multiple units 31, and after splitting, each unit 31 forms a heterojunction solar cell. For example... Figure 10 As shown, the top surface of the junction 32 between two adjacent units 31 is divided into a cutting area 321, a top surface conductive contact area 323, and a top surface bonding area 322; as Figure 12As shown, the bottom surface of the junction portion 32 between two adjacent units 31 is further provided with a bottom surface conductive contact area 323a and a bottom surface bonding area 322a located on the other side of the cutting area 312. The top surface conductive contact area 323a and the top surface bonding area 322a can form a top surface of an overlapping edge of a heterojunction solar cell; the bottom surface conductive contact area 323a and the bottom surface bonding area 322a can form a bottom surface of an overlapping edge of a heterojunction solar cell.

[0088] In this embodiment, no sub-grid lines are provided in the top surface conductive contact area 323 on the top surface of the large battery cell 300, but sub-grid lines are provided in the bottom surface conductive contact area 323a on the bottom surface.

[0089] Furthermore, refer to Figure 12 The sub-gate lines in the bottom surface conductive contact area 323a are staggered from the sub-gate lines in other areas of the bottom surface, and each sub-gate line in the bottom surface conductive contact area 323a is not collinear with any other sub-gate lines on the bottom surface of the substrate. A conductive strip 319 is also provided on the bottom surface of the substrate to separate the sub-gate lines in the bottom surface conductive contact area from other sub-gate lines, thereby electrically connecting the sub-gate lines in the bottom surface conductive contact area 323a to other sub-gate lines.

[0090] In this embodiment, the state after two heterojunction solar cells formed by splitting are connected in a shingled manner is... Figure 13 and Figure 14 As shown in the figure, in the area where the two heterojunction solar cells face each other, the sub-grid lines of the bottom surface conductive contact area of ​​one of them and the light-transmitting conductive film 313 of the top surface conductive contact area of ​​the other are in direct contact to achieve conductive connection. The adhesive 9 is disposed between the top surface bonding area and the bottom surface bonding area of ​​the two heterojunction solar cells.

[0091] Figures 15-16 A third embodiment of the present invention is shown. In this embodiment, the structural diagram of the large solar cell sheet is omitted, and only a schematic diagram of the solar cells 41 formed after the large solar cell sheet is split is shown after they are arranged in a shingled manner.

[0092] In this embodiment, sub-grid lines are provided on both the top surface conductive contact area and the bottom surface conductive contact area of ​​the large solar cell. However, the sub-grid lines on the top and bottom surface conductive contact areas are constructed such that when two heterojunction solar cells are connected in a shingled manner, the sub-grid lines on the top and bottom surface conductive contact areas facing each other are staggered and do not contact each other.

[0093] like Figure 16As shown, when the two heterojunction solar cells 41 are connected in a shingled manner, the light-transmitting conductive film 413 of the top surface conductive contact area of ​​one of them is in contact with the bottom sub-grid line 412a of the bottom surface conductive contact area of ​​the other; and the top sub-grid line 412b of the top surface conductive contact area is in direct contact with the light-transmitting conductive film 413 of the bottom surface conductive contact area.

[0094] In the three embodiments described above, each component may have other preferred configurations in addition to those already described.

[0095] For example, a non-conductive adhesive is preferred. When selecting an adhesive material, various factors must be considered, such as its impact on electrical connectivity, mechanical strength, and product reliability, as well as application compatibility and cost. Preferably, a liquid or highly fluid non-conductive material is chosen to facilitate penetration into the overlap gaps between adjacent heterojunction solar cells. Optional adhesive materials can be made from acrylic resin, silicone resin, epoxy resin, or polyurethane. To achieve a certain thickness, additives such as curing agents, crosslinking agents, coupling agents, or rubber balls can be added.

[0096] Because the adhesive is non-conductive, factors that could easily damage the conductive adhesive, such as environmental corrosion, alternating high and low temperatures, and thermal expansion and contraction, will not affect the shingled modules and heterojunction solar cells of this invention. Shingled modules and heterojunction solar cells are less prone to current leakage and open circuits, and the requirements for adhesive coating precision are reduced. Furthermore, since conductive adhesive is not required, problems such as open circuits between the positive and negative terminals of the cell string caused by adhesive overflow will not occur. In addition, because the conductivity of the adhesive is not required, the production cost of shingled modules is also reduced.

[0097] The adhesive can also be arranged in various ways. For example, the adhesive can be in the form of dots, with multiple adhesives intermittently disposed on the overlapping edges of each pair of adjacent heterojunction solar cells; or, the adhesive can be in the form of strips extending along the overlapping edges of each pair of adjacent heterojunction solar cells; or, the adhesive can be applied to the top surface of multiple heterojunction solar cells so that the adhesive spans multiple heterojunction solar cells, in which case the adhesive is preferably multiple and the multiple adhesives are arranged parallel to each other on the top surface of the cell string; or, multiple adhesives can be applied to the top surface and / or bottom surface of the heterojunction solar cells, and the individual adhesives may not be parallel to each other.

[0098] Preferably, the adhesive can be applied to each heterojunction solar cell first, and then the individual solar cells can be interconnected.

[0099] For example, the transparent conductive film can be configured to extend across the entire top and bottom surfaces of the substrate, and to have a uniform thickness at all locations before the individual heterojunction solar cells are interconnected. Thus, for example, for the transparent conductive film on the top surface of the central layer, after applying adhesive to the transparent conductive film at the top surface bonding area, the adhesive protrudes upwards from the transparent conductive film; for the transparent conductive film on the bottom surface of the central layer, after applying adhesive to the transparent conductive film at the bottom surface bonding area, the adhesive protrudes downwards from the transparent conductive film.

[0100] In this way, when two solar cells are interconnected in a shingled manner, the light-transmitting conductive films on their opposing surfaces bend at the adhesive joint due to the pressure of the adhesive, creating a gap between the light-transmitting conductive films immediately adjacent to the adhesive. This setup is relatively simple, requiring no additional processing of the light-transmitting conductive films, thus resulting in high production efficiency and low cost.

[0101] As an alternative to the above solution, the transparent conductive film has a notch at the location where the adhesive is placed to at least partially accommodate the adhesive. This ensures that when two solar cells are interconnected in a shingled manner, their transparent conductive films are in close contact without bending or other issues at the contact surfaces. This design avoids problems caused by the transparent conductive film being squeezed and deformed, and the stable containment of the adhesive within the notch prevents adhesive detachment and failure.

[0102] Preferably, the light-transmitting and conductive films on the top and / or bottom sides of the heterojunction solar cell can be multilayered, and the light transmittance of each of the light-transmitting and conductive films increases progressively in the direction perpendicular to the central layer. This arrangement can improve the carrier shift rate, light transmittance, and conductivity of the heterojunction solar cell, avoiding problems such as low fill factor and low open-circuit current, thus enabling the heterojunction solar cell to have a high photoelectric conversion efficiency.

[0103] The present invention also provides a preferred example of a method for manufacturing the above-described shingled module. The manufacturing method includes the following steps: manufacturing a large solar cell sheet as described in the above embodiments; cutting along each cutting section of the large solar cell sheet to divide it into multiple solar cells; and connecting the multiple solar cells in a shingled manner using a non-conductive adhesive, such that the light-transmitting conductive film of one of two adjacent solar cells and the sub-grid line of the other are in direct contact to achieve a conductive connection.

[0104] In this process, an adhesive can be applied to the light-transmitting conductive film of each heterojunction solar cell first, and then the light-transmitting conductive films can be connected to each other. Specifically, for two adjacent solar cells (referred to as the first heterojunction solar cell and the second heterojunction solar cell), the step of connecting them in a shingled manner using an adhesive with non-conductive properties includes the following steps in sequence: applying an adhesive to the light-transmitting conductive film of the bonding area on the top surface of the first heterojunction solar cell; connecting the first heterojunction solar cell and the second heterojunction solar cell to each other in a shingled manner, and fixing the two heterojunction solar cells to each other with the adhesive.

[0105] Preferably, the method further includes the following step between the step of applying an adhesive to the first heterojunction solar cell and the step of interconnecting the first heterojunction solar cell and the second heterojunction solar cell: applying an adhesive to the light-transmitting conductive film in the bonding area on the bottom surface of the second heterojunction solar cell.

[0106] Alternatively, the individual heterojunction solar cells can be arranged in a shingled manner, and then an adhesive can be applied on top of them. This method can be implemented in several different ways.

[0107] The step of applying adhesive may include: intermittently applying adhesive along the overlapping edge of each pair of adjacent heterojunction solar cells, so that the adhesive is formed into a plurality of dot-like structures spaced apart along the overlapping edge.

[0108] Alternatively, the step of applying the adhesive may include: continuously applying the adhesive along the overlap edge of each pair of adjacent heterojunction solar cells, so that the adhesive forms a strip structure extending along the overlap edge.

[0109] Alternatively, the steps of applying the adhesive may include: continuously applying the adhesive along the arrangement direction of each heterojunction solar cell, so that the adhesive spans multiple heterojunction solar cells.

[0110] Preferably, the above-mentioned methods of applying adhesive can be achieved by spraying, dripping, rolling, printing, or brushing.

[0111] Preferably, the adhesive can also be applied using a stencil with cutouts. The method of applying the adhesive includes the following steps: positioning the stencil on the top surface of each of the arranged heterojunction solar cells, and applying the adhesive to the stencil so that the adhesive is printed at the desired position through the cutouts.

[0112] As described above, since the central layer of a heterojunction solar cell also has a multilayer structure, the method for manufacturing a complete heterojunction solar cell includes: setting a silicon wafer; setting a top-side intrinsic amorphous silicon thin film on the top surface of the silicon wafer and a bottom-side intrinsic amorphous silicon thin film on the bottom surface of the silicon wafer; setting a light-transmitting conductive film on the top surface of the top-side intrinsic amorphous silicon thin film and the bottom surface of the bottom-side intrinsic amorphous silicon thin film; and setting sub-grid lines on the light-transmitting conductive film. Preferably, the method for manufacturing a complete heterojunction solar cell does not include the step of setting main grid lines.

[0113] The large solar cell provided by this invention facilitates the dicing process, and the large solar cell is provided with a conductive contact area for conductive connection of heterojunction solar cells and an adhesive area for applying adhesive. This configuration can optimize the production process and performance of heterojunction solar cells.

[0114] Furthermore, the heterojunction solar cells formed by splitting can achieve conductive connection through direct contact between the light-transmitting conductive film and the sub-grid lines, thus allowing the use of non-conductive adhesives for fixation. This has at least the following advantages:

[0115] First, the good conductivity of the light-transmitting conductive film can optimize the performance of shingled modules and also eliminate the need for electrodes to reduce costs.

[0116] Second, the adhesive may be non-conductive, so factors that easily damage the conductive adhesive, such as environmental corrosion, high and low temperature alternation, and thermal expansion and contraction, will not affect the shingled assembly of the present invention. The shingled assembly is less prone to current connection failure and open circuit, and problems such as open circuit of positive and negative terminals of battery string caused by conductive adhesive overflow will not occur.

[0117] The above description of various embodiments of the present invention is provided for illustrative purposes to a person of ordinary skill in the art. It is not intended to exclude or limit the invention to a single disclosed embodiment. As described above, those of ordinary skill in the art will understand various alternatives and variations of the invention. Therefore, although some alternative embodiments have been specifically described, those of ordinary skill in the art will understand or relatively easily develop other embodiments. The present invention is intended to include all alternatives, modifications, and variations of the invention described herein, as well as other embodiments falling within the spirit and scope of the invention described above.

[0118] Figure label:

[0119] Large battery cells, 100, 300

[0120] Unit 1, 31

[0121] Solar cell 41

[0122] Boundary section 2, 32

[0123] Cutting areas 21, 312

[0124] Top surface bonding areas 22, 322

[0125] Top surface conductive contact areas 23, 323

[0126] Matrix 11, 311

[0127] Sub-gate line 12

[0128] Top sub-gate line 412b

[0129] Bottom sub-gate line 412a

[0130] Bottom surface bonding areas 22a, 322a

[0131] Bottom surface conductive contact areas 23a, 323a

[0132] Transparent conductive films 13, 313, 413

[0133] Adhesive 9

[0134] Conductive strip 319

Claims

1. A large solar cell sheet, used for splitting to form multiple heterojunction solar cells, wherein the multiple heterojunction solar cells can be arranged in a shingled manner to form a cell string. in, The large battery cell includes a substrate sheet, which includes a central layer and light-transmitting conductive films disposed on the top and bottom surfaces of the central layer. The large battery cell is divided into multiple units arranged along a first direction, with any two adjacent units forming a first unit and a second unit. When the large battery cell is split into smaller pieces, the first unit forms a first battery cell, and the second unit forms a second battery cell. The feature is that the top surface of the boundary portion between the first unit and the second unit is divided into: A cutting region extending in a direction perpendicular to the first direction, the cutting region being configured to allow the large battery cell to be cut along it; and The top surface bonding area and the top surface conductive contact area are disposed on one side of the cutting area, and the top surface bonding area and the top surface conductive contact area are alternately arranged in a direction perpendicular to the first direction. The cutting area and the top surface conductive contact area form the top surface of an overlapping edge of the second battery cell. The top surface bonding area and the top surface conductive contact area are configured such that when the second solar cell is located in the solar cell string, an adhesive can be applied to the top surface of the top surface bonding area to fix it to the bottom surface of the adjacent heterojunction solar cell, and the top surface conductive contact area can directly contact the bottom surface of the adjacent heterojunction solar cell to achieve conductive connection. In this embodiment, sub-grid lines are provided on the top and / or bottom surfaces of the substrate sheet of the large solar cell. When multiple heterojunction solar cells formed by splitting the large solar cell sheet are arranged into a cell string, the sub-grid lines of one of any adjacent pair of heterojunction solar cells can directly contact the transparent conductive film of the other to achieve conductive connection. The substrate sheet of the large battery cell does not have main busbars.

2. The large battery cell according to claim 1, characterized in that, Sub-grid lines are provided on the top surface of the substrate sheet of the large battery cell, and the sub-grid lines extend into the conductive contact area of ​​the top surface.

3. The large battery cell according to claim 1, characterized in that, Sub-grid lines are provided on the top surface of the substrate sheet of the large battery cell, and there are no sub-grid lines in the conductive contact area of ​​the top surface.

4. The large battery cell according to claim 1, characterized in that, Sub-grid lines are provided on both the top and bottom surfaces of the substrate sheet of the large solar cell, and the sub-grid lines are configured such that in the cell string composed of heterojunction solar cells formed by splitting the cells, the sub-grid lines on the areas facing each other of any two heterojunction solar cells are staggered so as not to contact each other.

5. The large battery cell according to claim 4, characterized in that, A bottom surface bonding area and a bottom surface conductive contact area are further provided on the bottom surface of the junction of the first unit and the second unit. The bottom surface bonding area and the bottom surface conductive contact area are located on the other side of the cutting area in the first direction and are alternately arranged in a direction perpendicular to the first direction. The bottom surface bonding area and the bottom surface conductive contact area form the bottom surface of an overlapping edge of the first battery cell.

6. The large battery cell according to claim 5, characterized in that, Each of the subgate lines extends along the first direction, but each subgate line in the bottom surface conductive contact area is not collinear with any other subgate line on the bottom surface of the substrate.

7. The large battery cell according to claim 6, characterized in that, Each of the units has a conductive strip on its bottom surface that separates the bottom surface bonding area, the bottom surface conductive contact area, and other areas of the bottom surface. The sub-gate lines on the other areas of the bottom surface and the sub-gate lines on the bottom surface conductive contact area are in contact.

8. The large battery cell according to claim 5, characterized in that, The light-transmitting conductive film extends across the entire top and bottom surfaces of the central layer.

9. The large battery cell according to claim 5, characterized in that, The transparent conductive film is not present in the top surface bonding area and the bottom surface bonding area.

10. The large battery cell according to claim 1, characterized in that, The top surface of the junction between the first unit and the second unit at the foremost front end of the large battery cell is further provided with another set of top surface bonding areas and top surface conductive contact areas. The other set of top surface bonding areas and top surface conductive contact areas are located on the other side of the cutting area, and the other set of top surface bonding areas and top surface conductive contact areas form the top surface of an overlapping edge of the first battery cell.

11. The large battery cell according to claim 1, characterized in that, The central layer includes a silicon wafer, a top-side intrinsic amorphous silicon film disposed on the top surface of the silicon wafer, a P-type amorphous silicon film disposed on the top surface of the top-side intrinsic amorphous silicon film, a bottom-side intrinsic amorphous silicon film disposed on the bottom surface of the silicon wafer, and an N-type amorphous silicon film disposed on the bottom surface of the bottom-side intrinsic amorphous silicon film.

12. A heterojunction solar cell, wherein the heterojunction solar cell is formed by splitting a large sheet of solar cell according to any one of claims 1-11.

13. The heterojunction solar cell according to claim 12, characterized in that, The light-transmitting conductive film extends across the entire top and bottom surfaces of the central layer, and has the same thickness everywhere, such that when an adhesive is applied to the bonding area on the top surface, the adhesive protrudes beyond the light-transmitting conductive film, thereby separating the light-transmitting conductive films on the opposing surfaces of the two heterojunction solar cells at the adhesive when the heterojunction solar cell is connected to another heterojunction solar cell.

14. The heterojunction solar cell according to claim 12, characterized in that, The transparent conductive film has a notch in the bonding area on the top surface. When an adhesive is applied to the heterojunction solar cell, the adhesive is located within the notch and does not protrude from the transparent conductive film.

15. The heterojunction solar cell according to claim 12, characterized in that, The heterojunction solar cell has an overlap edge that contacts another heterojunction solar cell, which is provided with a top surface bonding area and a top surface conductive contact area that extend along the overlap edge and are alternately arranged on the overlap edge. The top surface conductive contact area also contains sub-grid lines, or the top surface conductive contact area does not contain sub-grid lines.

16. The heterojunction solar cell according to claim 15, characterized in that, Sub-gate lines also exist within the conductive contact area of ​​the top surface, and each sub-gate line in the conductive contact area of ​​the top surface is not collinear with any other sub-gate lines on the surface where the conductive contact area of ​​the top surface is located, except for the conductive contact area itself. The heterojunction solar cell has a conductive strip on the surface where the top surface conductive contact area is located, which separates the top surface conductive contact area, the top surface bonding area, and other parts of the surface. The sub-grid lines of the top surface conductive contact area and the sub-grid lines of other parts of the surface are all conductively connected to the conductive strip.

17. A shingled module comprising a battery string, characterized in that, The battery string is formed by sequentially connecting multiple heterojunction solar cells according to any one of claims 12-16 in a shingled manner. Each heterojunction solar cell is fixed to each other by an adhesive. Sub-grid lines are provided on the top surface and / or bottom surface of the heterojunction solar cells. The light-transmitting conductive film of one of two adjacent heterojunction solar cells can directly contact the sub-grid line of the other two heterojunction solar cells to achieve conductive connection between the two adjacent heterojunction solar cells.

18. The shingled assembly according to claim 17, characterized in that, The adhesive is a non-conductive adhesive.

19. The shingled assembly according to claim 17, characterized in that, The adhesive is a dot-structure adhesive made of acrylic resin, silicone resin, epoxy resin or polyurethane.

20. The shingled assembly according to claim 17, characterized in that, The adhesive is a dotted structure comprising a curing agent, a crosslinking agent, a coupling agent, or rubber balls.

21. A manufacturing method for manufacturing shingled modules, characterized in that, The method includes the following steps: Manufacture a large solar cell sheet according to any one of claims 1-11, wherein the large solar cell sheet has sub-busbars; Cut along each cutting area of ​​the large solar cell sheet, thereby splitting the large solar cell sheet into multiple heterojunction solar cells; Multiple heterojunction solar cells are connected in a shingled manner using a non-conductive adhesive, so that the transparent conductive film of one of two adjacent heterojunction solar cells and the sub-grid line of the other are in direct contact, thereby achieving a conductive connection.

22. The manufacturing method according to claim 21, characterized in that, The method further includes the step of applying an adhesive to the heterojunction solar cell in one of the following ways: spraying, dripping, rolling, printing, or brushing.

23. The manufacturing method according to claim 22, characterized in that, The method for manufacturing large solar cells does not include the step of setting up the main busbars.

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