Solar modules

Abstract

Embodiments of this application relate to a solar module, comprising: a substrate and a plurality of solar cells connected in series on the substrate, wherein each of the plurality of solar cells includes a back electrode layer, an absorber layer, a window and a buffer layer, a laminate layer, a front glass plate, and structured lines P1, P2, and P3; structured line P1 extends through the back electrode layer and is filled with the material of the absorber layer; structured line P2 extends through the absorber layer and is filled with the material of the window and the buffer layer; and structured line P3 extends through the window, the buffer layer, and the absorber layer; characterized in that: the solar module further includes an opaque and reflective linear structure disposed in a dead zone formed by structured lines P1, P2, and P3, and disposed on the side of the window and the buffer layer near the front glass plate; the linear structure extends in a lateral direction from the edge of structured line P1 away from structured line P2 through structured line P2 to the edge of structured line P3 near structured line P2, the lateral direction being perpendicular to the direction in which the layers are stacked in the solar module.

Description

Technical Field

[0001] This disclosure relates to the field of solar energy technology, and more particularly to solar modules. Background Technology

[0002] Typically, thin-film solar modules are monolithic circuits formed by connecting multiple individual solar cells in series. These individual solar cells are interconnected through structured regions formed by structured lines P1, P2, and P3 (e.g., ...). Figure 1 (As shown). Thin-film solar modules typically include a back electrode layer, an absorber layer, a window and buffer layer, a laminate layer, and a front glass panel. The back electrode layer, absorber layer, and window and buffer layer are separated by structured lines P1, P2, and P3, respectively. No electricity is generated in the structured region formed by structured lines P1, P2, and P3. Therefore, the structured region is often referred to as the "dead zone," see [reference]. Figure 1 .

[0003] Improving the structuring process to reduce dead zones is crucial for improving short-circuit current density, and therefore essential for gradually increasing the efficiency of solar modules. However, the reduction of dead zones is technically limited and cannot be designed without losses.

[0004] Furthermore, the structuring process introduces structural and electrical defects into the solar modules, resulting in additional losses. These losses increase as the structuring distance and structuring linewidth (the sum of which equals the width of the dead zone) decrease, further limiting improvements in solar module efficiency.

[0005] To date, attempts have been made to reduce electrical and structural defects by controlling the structuring process; however, this is difficult to achieve due to the extensive interactions between the various layers during structuring and is limited by process technology. Irradiation of the solar module leads to increased losses in the dead zone due to the shunt path in the structured line P1. Compared to the techniques mentioned above, the dielectric within the structured line P1 helps enhance the P1 shunt path but does not benefit the photon yield and light management of the solar module.

[0006] Therefore, there is a need for a solar module that can increase photon yield while improving shunting in dead zones. Summary of the Invention

[0007] The purpose of this application is to provide a solar module that can reflect photons entering the dead zone onto the semiconductor stack, improve the shunting in the dead zone, and thus improve the efficiency of the solar module.

[0008] Embodiments of this application provide a solar module comprising: a substrate and a plurality of solar cells connected in series on the substrate, wherein each of the plurality of solar cells includes a back electrode layer, an absorber layer, a window and a buffer layer, a laminate layer, a front glass plate, and structured lines P1, P2, and P3; structured line P1 extends through the back electrode layer and is filled with the material of the absorber layer; structured line P2 extends through the absorber layer and is filled with the material of the window and the buffer layer; structured line P3 extends through the window, the buffer layer, and the absorber layer; wherein the solar module further includes an opaque and reflective linear structure disposed in a dead zone formed by structured lines P1, P2, and P3, and located on the side of the window and the buffer layer near the front glass plate; the linear structure extends in a lateral direction from the edge of structured line P1 away from structured line P2 to the edge of structured line P3 near structured line P2, the lateral direction being perpendicular to the direction in which the layers are stacked in the solar module.

[0009] The solar modules provided in this application, particularly thin-film solar modules (CdTe, CIGS, etc.), can be stably used in monolithic interconnect substrates and top-mass structures. Specifically, this application relates to CIGS thin-film solar modules. The solar modules of this application can increase the number of photons absorbed in the absorption layer by reflecting photons entering the dead zone back to the absorption layer. Furthermore, the solar modules of this application can increase the shunt resistance by darkening the dead zone, particularly the area in the structured line P1, thereby increasing the short-circuit current density. A voltage difference exists across the trenches of the structured line P1. This voltage difference causes current to flow through the material of the absorption layer located in the trenches, which can be affected by various factors, such as the width of the trenches of the structured line P1, the conductivity of the absorption layer material in the trenches, and the light dependence of the absorption layer material. By darkening the dead zone (especially the trenches), the solar modules of this application reduce the conductivity of the absorption layer material in the trenches of the structured line P1, thereby increasing the shunt resistance, i.e., reducing the shunt path. (Per square centimeter (cm)) 2 The shunt resistance can be increased by several hundred ohms, and the efficiency of the solar module can be relatively improved by 0.5% to 2%. Therefore, the short-circuit current density also increases relatively by about 0.5% to 2%.

[0010] By reflecting photons entering the dead zone to the absorption layer, the linear structure of this application increases the number of photons absorbed by the absorption layer of the solar module. Furthermore, the linear structure reduces shunt paths in the structured region, thereby improving the efficiency of the solar module. Compared to conventional grids that require good conductivity, the linear structure of this application only requires opacity and reflection, without requiring conductivity. Moreover, a grid parallel to the structured lines that is conductive but almost non-reflective contributes little to the efficiency improvement. Attached Figure Description

[0011] To more clearly describe the embodiments of this disclosure or the technical solutions of the prior art, the accompanying drawings used in the embodiments and the prior art will be briefly described below. Obviously, the drawings provided below are only for some embodiments of this disclosure. The same reference numerals in the drawings represent the same or similar elements.

[0012] Figure 1 A cross-sectional view of a solar module according to an embodiment of this application is shown. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this application clearer and easier to understand, this application will be described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure fall within the protection scope defined by this disclosure.

[0014] Generally, solar modules manufactured using thin-film PV technology are referred to as thin-film solar modules. Thin-film solar modules can include, for example, copper indium gallium selenide (CIGS) thin-film solar modules, cadmium telluride (CdTe) thin-film solar modules, organic photovoltaic (OPV) thin-film solar modules, perovskite thin-film solar modules, dye-sensitized solar cell (DSSC) modules, and heterojunction with intrinsic thin film (HJT) solar cell modules. The specific structures and manufacturing methods of various thin-film solar modules are known in the solar energy field and will not be described in detail here.

[0015] Figure 1 This is a cross-section of a thin-film solar module 1 according to an embodiment of this application. The thin-film solar module 1 includes a front glass panel 11, a laminate layer 12, a window and buffer layer 13, an absorption layer 14, a back electrode layer 15, and an opaque and reflective linear structure 16.

[0016] The window and buffer layer 13, the absorber layer 14, and the back electrode layer 15 forming the semiconductor stack are separated by structured lines P1, P2, and P3. Structured line P1 extends through the back electrode layer 15 and is filled with the material of the absorber layer 14. Structured line P2 extends through the absorber layer 14 and is filled with the material of the window and buffer layer 13. Structured line P3 extends through the window and buffer layer 13 and the absorber layer 14.

[0017] The front glass panel 11 is located on the front side of the solar module 1, i.e., the side from which sunlight enters the solar module 1. The front glass panel 11 can be made of soda-lime glass, silicate glass, special silicate glass (low-iron glass), borosilicate glass, aluminosilicate glass, or chemically strengthened glass (potassium glass). The front glass panel 11 can be transparent or translucent, and can be colored or colorless. The front glass panel 11 can be formed using float glass or rolled glass processes. The surface of the front glass panel 11 can be flat or textured (acid-etched, sandblasted, or rolled).

[0018] A substrate (not shown) is located on the back side of the solar module 1, opposite the front side of the solar module 1. The substrate may be made of a material such as glass, polymer, or metal.

[0019] Laminate 12 is a polymer laminate in solar module 1, used for glass bonding in practical applications. Laminate 12 can be made of EVA, POE, EVA-POE-EVA, PDMS / silicone, PVB, or TPU, etc. The laminate can be formed by foil or non-foil (hot melt) lamination.

[0020] A window and buffer layer 13 are disposed on the absorber layer 14. The window and buffer layer 13 includes a buffer layer and a conductive window layer. The buffer layer is an n-type semiconductor layer, which may be a silicon-based thin film such as amorphous silicon, germanium, monocrystalline silicon, and polycrystalline silicon, or a compound thin film such as copper indium gallium selenide, cadmium telluride, and gallium arsenide. The conductive window layer is located above the buffer layer. The conductive window layer is a transparent conductive oxide layer, which may be indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), or the like.

[0021] An absorption layer 14 is disposed on the back electrode layer 15. The absorption layer 14 is a p-type semiconductor layer, which can be a silicon-based thin film such as amorphous silicon, germanium, monocrystalline silicon, and polycrystalline silicon, or a compound thin film such as copper indium gallium selenide, cadmium telluride, and gallium arsenide. A pn ​​junction is formed between the absorption layer 14 and the buffer layer.

[0022] A back electrode layer 15 is disposed on a substrate (not shown). The back electrode layer 15 can be a metal electrode or a transparent conductive thin film electrode. For example, the metal electrode can be a highly conductive metal, such as copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, manganese, etc. The transparent conductive thin film electrode can be AZO, ITO, or the like.

[0023] The opaque and reflective linear structure 16 has low-light and dark-light management modes (LDMP). The opaque and reflective linear structure 16 is disposed in the dead zone formed by structured lines P1, P2, and P3 and is located on the side of the window and buffer layer 13 near the front glass panel 11. The linear structure 16 extends laterally from the edge of structured line P1 away from structured line P2, through structured line P2, to the edge of structured line P3 near structured line P2, this lateral direction being perpendicular to the direction of the stacked layers in the solar module, or in other words, parallel to the surfaces of the layers.

[0024] In embodiments of this application, in the dead zone, a linear structure 16 is disposed on the side of the window and buffer layer 13 near the front glass panel 11 and above the window and buffer layer 13. The linear structure 16 is substantially opaque and highly reflective.

[0025] The linear structure reflects incident photons. (Example) Figure 1 As shown, photons passing through the front glass panel 11 from the light incident side of the solar module are reflected back to the interface between the laminate layer 12 and the front glass panel 11 by the linear structure 16, particularly to the interface between the front glass panel 11 and the air. The photons reflected back to this interface can be reflected again into the absorption layer and absorbed by it to generate additional electrical energy. In other words, these lost photons are reabsorbed by backscattering / backreflecting photons lost in the dead zone, which is not present in existing technologies with the linear structure 16.

[0026] In this application, diffuse reflection of photons is advantageous. If the front glass plate has a structured surface, the number of back-reflected photons that can be reabsorbed by the absorption layer will increase. Furthermore, due to the opacity of the linear structure 16, the linear structure 16 will cause the structured region to darken, especially the region formed by the side of structured line P2 near structured line P1, structured line P2, and structured line P3. Therefore, in this region of the dead zone, the light-induced shunting path and loss mechanism are improved, thereby reducing light shunting and improving weak light. This additional linear structure is particularly effective for solar cell modules with a large number of cells, a high percentage of dead zones and structured lines, and severely damaged structured regions. Technically, this additional linear structure is achieved by applying a highly reflective material or a combination of materials to the dead zone.

[0027] In this application, the geometric pattern of the linear structure is designed to achieve effective backscattering / reflection of photons, and it is arranged in a region extending from the side of the structured line P1 to the side of the structured line P3 near the side of the structured line P2, to reliably prevent the effective photovoltaic region from being covered. Figure 1As shown, the linear structure 16 extends laterally from the outer edge of structured line P1 away from structured line P2, through structured line P2, to the inner edge of structured line P3 near structured line P2. In the lateral direction, the width of the linear structure 16 is equal to the distance from the edge of structured line P1 away from structured line P2 to the edge of structured line P3 near structured line P2. Furthermore, the linear structure 16 may have a slightly smaller width, which is the distance from a position in structured line P1 near the outer edge of structured line P1 to a position in the absorption layer near the inner edge of structured line P3. In one embodiment of this application, the width of the linear structure 16 may be from 50 μm to approximately 300 μm for mass production of full-size solar modules.

[0028] In this application, the surface of the linear structure for effective backscattering / reflection of photons can be a rough surface with a high proportion of diffuse backscattering / reflection. The linear structure can have a specific structured surface with a three-dimensional structure, which can be constructed from multiple pyramids, polyhedra, grooves or channels, or combinations thereof.

[0029] The linear structure is made of a highly reflective material. The reflectivity of the highly reflective material is greater than 90%. The highly reflective material can include metallic and non-metallic materials. For example, the metallic material can be at least one selected from silver, aluminum, copper, alloys, and the like. The non-metallic material can be at least one selected from TiO2, Al2O3, ZrO2, Si3N4, and the like. In addition, metallic or non-metallic materials can also be incorporated into glass or polymer slurries as reflective particles or pigments.

[0030] The linear structure exhibits high reflectivity (greater than 85%) over a wide wavelength range of spectral sensitivity in solar cells. The adjacent dielectric material to the linear structure is an encapsulation film in the case of a substrate structure, or a front glass plate in the case of a top substrate structure. The refractive index of both the encapsulation film and the front glass plate is 1.5.

[0031] In this application, the thickness of the linear structure is not critical as long as the optical properties are met. Although a larger thickness will affect the lamination process, its impact on the performance of the linear structure is relatively small compared to its width (50 μm to 300 μm).

[0032] Solar modules with a non-metallic reflective layer (linear structure) differ from solar modules produced using grid technology where conductivity plays a core role. Compared to solar modules without a linear structure, solar modules with a linear structure exhibit a relative increase in current density of 0.5% to 2%.

[0033] In this application, the linear structure can be manufactured by conventional printing processes such as inkjet, aerosol jetting, screen printing, or similar methods.

[0034] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are all included within the scope of protection of this application.

Claims

1. A solar module, comprising: A substrate and a plurality of solar cells connected in series on the substrate, wherein each of the plurality of solar cells includes a back electrode layer, an absorber layer, a window and a buffer layer, a laminate, a front glass plate, and structured lines P1, P2, and P3; structured line P1 extends through the back electrode layer and is filled with the material of the absorber layer; structured line P2 extends through the absorber layer and is filled with the material of the window and the buffer layer; structured line P3 extends through the window and the buffer layer and the absorber layer. Its features are: The solar module also includes an opaque and reflective linear structure disposed in the dead zone formed by structured lines P1, P2, and P3 and on the side of the window and buffer layer near the front glass panel. The linear structure extends laterally from the edge of structured line P1 away from structured line P2, through structured line P2, to the edge of structured line P3 near structured line P2, the lateral direction being perpendicular to the direction of the stacked layers in the solar module. The linear structure has a three-dimensional structured surface constructed from multiple pyramids, polyhedra, grooves or channels, or combinations thereof. Photons passing through the front glass panel from the light incident side of the solar module are reflected back to the interface between the laminate and the front glass panel by the linear structure, allowing the reflected photons to be reflected again into the absorption layer and absorbed to generate additional electrical energy. The linear structure is made of a highly reflective material with a reflectivity greater than 90%.

2. The solar module according to claim 1, wherein, The highly reflective material includes metallic or non-metallic materials.

3. The solar module according to claim 2, wherein, The metallic material is selected from at least one of silver, aluminum, copper and their alloys, and the non-metallic material is selected from at least one of TiO2, Al2O3, ZrO2 and Si3N4.

4. The solar module according to claim 1, wherein, The linear structure has a width of 50µm to 300µm.

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