Multilayer photovoltaic devices and manufacturing methods

Abstract

This invention provides a tandem photovoltaic device and its manufacturing method, relating to the field of photovoltaic technology. The tandem photovoltaic device includes: an upper battery cell, a lower battery cell, an insulating layer, and an intermediate series structure; the upper battery cell is a thin-film solar cell; the lower battery cell has a light-facing surface and a back-lighting surface arranged opposite each other, and a side surface connecting the light-facing surface and the back-lighting surface; the insulating layer is at least wrapped around the side surface of the lower battery cell. Wrapping the insulating layer around the side surface of the lower battery cell ensures that the coating or plating of the thin-film solar cell on its lower side is located on the insulating layer and does not contact the side surface of the lower battery cell. This avoids direct coating or plating of the thin-film solar cell on the side surface of the lower battery cell, significantly reducing short circuits between the upper and lower battery cells, and improving the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a multilayer photovoltaic device and its manufacturing method. Background Technology

[0002] Multilayer photovoltaic devices can divide sunlight into multiple bands. From the front to the back, solar cell units with gradually decreasing band gaps absorb sunlight of different energies to reduce energy loss in the visible light band and improve photoelectric conversion efficiency.

[0003] However, in tandem photovoltaic devices, those with thin-film solar cells as the upper cell unit typically have low power generation efficiency and poor production yield. Summary of the Invention

[0004] This invention provides a tandem photovoltaic device and its manufacturing method, aiming to solve the problems of low power generation efficiency and poor production yield of tandem photovoltaic devices where the upper battery unit is a thin-film solar cell. According to a first aspect of the invention, a tandem photovoltaic device is provided, comprising: an upper battery unit, a lower battery unit, and an intermediate series structure located between the upper battery unit and the lower battery unit;

[0005] The upper battery unit is a thin-film solar cell;

[0006] The lower battery cell has a light-facing surface and a back-light surface arranged opposite to each other, as well as a side surface connecting the light-facing surface and the back-light surface;

[0007] The tandem photovoltaic device also includes an insulating layer that wraps around at least the side of the lower battery cell.

[0008] In this application, an insulating layer is wrapped around the side of the lower battery cell, so that the coating or coating of the thin-film solar cell on its lower side is located on the insulating layer and does not come into contact with the side of the lower battery cell. This avoids direct coating or coating of the thin-film solar cell on the side of the lower battery cell, which greatly reduces the short circuit between the upper and lower battery cells and can improve the power generation efficiency and production yield of the tandem photovoltaic device. Moreover, the manufacturing process is simple and the production cost is low.

[0009] Optionally, the insulating layer further extends to at least a portion of the side surface of the first layer; the first layer is a layer with charge carrier conductivity in the intermediate series structure, or the first layer is a layer with charge carrier conductivity in the portion of the upper battery cell near the intermediate series structure.

[0010] Optionally, the insulating layer extends and covers the edge region of the light-facing surface of the lower battery cell;

[0011] And / or, the insulating layer extends and covers the edge region of the backlight surface of the lower battery cell.

[0012] Optionally, the insulating layer extends and covers the edge region of the light-facing surface of the first layer;

[0013] And / or, the insulating layer extends and covers the edge region of the backlight surface of the first layer.

[0014] Optionally, the first layer is a lower transmission layer close to the lower battery cell.

[0015] Optionally, the upper battery cell includes a buffer layer;

[0016] The insulating layer also extends to cover at least a portion of the sides of the buffer layer.

[0017] Optionally, the stacked photovoltaic device further includes a lower functional film located on the back surface of the lower battery cell, the lower functional film including a back transmission layer;

[0018] The insulating layer also extends to cover at least a portion of the sides of the back transmission layer.

[0019] Optionally, the thickness of the insulating layer is greater than or equal to 10 nm; the insulating layer is a single layer or multiple layers.

[0020] Optionally, the insulating layer is disposed on the light-facing surface of the lower battery cell;

[0021] An insulating layer disposed on the light-facing surface of the lower battery cell has at least one through-hole, and each through-hole is filled with a conductive material; the insulating layer disposed on the light-facing surface of the lower battery cell and the conductive material filled in the through-hole form the intermediate series structure.

[0022] Optionally, the insulation strength of the insulating layer is greater than or equal to 3MV / cm.

[0023] Optionally, when the lower battery cell is a crystalline silicon solar cell, the insulating layer is at least one of the following: silicon oxide layer, silicon nitride layer, silicon oxyfluoride layer, silicon oxycarbonate layer, aluminum oxide layer, aluminum fluoride layer, aluminum oxynitride layer, and magnesium fluoride layer.

[0024] Optionally, the side insulating layer includes a silicon oxide layer, an aluminum oxide layer, and a silicon nitride layer stacked sequentially, wherein the silicon oxide layer is in contact with the lower battery cell.

[0025] According to a second aspect of the present invention, a method for manufacturing a tandem photovoltaic device is provided, comprising the following steps:

[0026] A lower battery cell is provided; the lower battery cell has a light-facing surface and a back-lighting surface disposed opposite to each other, and a side surface connecting the light-facing surface and the back-lighting surface;

[0027] An insulating layer is obtained at least on the sides of the lower battery cell by deposition or growth.

[0028] An intermediate series structure is fabricated on the light-facing surface of the lower battery cell;

[0029] The upper battery cell is deposited on the light-facing surface of the intermediate series structure; the lower battery cell is a thin-film solar cell.

[0030] The production method of the above-mentioned tandem photovoltaic device has the same or similar beneficial effects as the aforementioned tandem photovoltaic device. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A schematic diagram of the structure of the first type of stacked photovoltaic device in an embodiment of the present invention is shown;

[0033] Figure 2 A schematic diagram of the structure of a second type of stacked photovoltaic device according to an embodiment of the present invention is shown;

[0034] Figure 3 A schematic diagram of the structure of the third type of stacked photovoltaic device in an embodiment of the present invention is shown;

[0035] Figure 4 A schematic diagram of the structure of the fourth type of stacked photovoltaic device in an embodiment of the present invention is shown;

[0036] Figure 5 A schematic diagram of the structure of the fifth type of stacked photovoltaic device in an embodiment of the present invention is shown;

[0037] Figure 6 A schematic diagram of the structure of the sixth type of stacked photovoltaic device according to an embodiment of the present invention is shown.

[0038] Explanation of the attached drawing numbers:

[0039] 1-Lower battery cell, 2-Insulating layer, 3-Upper battery cell, 31-Lower transport layer, 32-Upper transport layer, 33-Substrate of upper battery cell, 4-Intermediate series structure, 5-Upper functional film, 6-Lower functional film, 7-Top electrode, 8-Bottom electrode. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The inventors of this application have discovered that the main reason for the low power generation efficiency and poor production yield of stacked photovoltaic devices with thin-film solar cells as the upper battery unit is that thin-film solar cells are prone to being coated or coated on the side of the lower battery unit, which can lead to short circuits between the upper and lower battery units.

[0042] In an embodiment of the present invention, reference is made to Figure 1 As shown, Figure 1 A schematic diagram of the structure of a first type of stacked photovoltaic device according to an embodiment of the present invention is shown. The stacked photovoltaic device includes: a lower battery cell 1, an upper battery cell 3, an insulating layer 2, and an intermediate series structure 4 located between the upper battery cell 3 and the lower battery cell 1. This intermediate series structure 4 is used to connect the upper battery cell 3 and the lower battery cell 1 in series to form the stacked photovoltaic device. The upper battery cell 3 is a thin-film solar cell, which may include amorphous silicon thin-film solar cells, amorphous silicon carbide thin-film solar cells, copper indium gallium selenide sulfur thin-film solar cells, cadmium telluride thin-film solar cells, gallium arsenide solar cells, perovskite solar cells, organic thin-film solar cells, quantum dot thin-film solar cells, group III-V solar cells, etc., and the present invention does not specifically limit the types of cells.

[0043] It is understood that the upper battery cell 3 and the lower battery cell 1 have different bandgap widths, and the bandgap of the upper battery cell 3 is larger than that of the lower battery cell 1. For example, the bandgap width of the upper battery cell 3 is 1.5-2.3 eV. In this embodiment of the invention, the number of upper battery cells, lower battery cells, and intermediate series structures included in the tandem photovoltaic device are not specifically limited. The upper and lower battery cells can be electrically and optically adapted to achieve the best effect.

[0044] The light-facing surface of the upper battery cell 3 can have one or more functional layers such as a transmission layer, passivation layer, window layer, antireflection layer, and light-trapping layer. The light-facing surface of the upper battery cell 3 can be a planar surface, a textured surface, a nano-light-trapping structure, or other structures.

[0045] The lower-layer cell 1 can be a crystalline silicon cell. The doping type of the silicon substrate material in the lower-layer cell 1 is not limited; it can be a front-side pn junction or a back-side pn junction structure, and it can be a single-sided or double-sided structure. The light-facing surface of the lower-layer cell 1 can be a planar structure or have a light-trapping structure. The light-facing surface of the lower-layer cell 1 can have one or more functional structures such as transport layers, passivation layers, and buffer layers. The back-lighting surface of the lower-layer cell 1 can also have one or more functional structures such as transport layers, passivation layers, and buffer layers. For example, the lower-layer cell 1 can have a TOPCon (Tunnel Oxide Passivated Contact) structure, a PERC (Passivated Emitter and Rear Contact) structure, a PERT (Passivated Emitter and Rear Totally-diffused) structure, a PERL (Passivated Emitter and Rear Locally-diffused) structure, an Al-BSF structure, a SHJ structure, a POLO structure, a DASH structure, etc. The lower-layer cell 1 can employ deep junction or shallow junction processes.

[0046] Understandably, the intermediate series structure 4 is transparent, allowing light to pass through the wavelengths remaining after absorption by the upper battery cells. This transparent wavelength range can be determined based on the wavelengths remaining after absorption by the adjacent upper battery cells. For example, the transparent wavelength range can be the wavelengths remaining after absorption by the adjacent upper battery cells. The intermediate series structure 4 serves to connect the upper and lower battery cells in series and can be a single or multiple structure, employing structures such as metal series connection, transparent transport layer, composite layer, or tunnel junction. For instance, the intermediate series structure 4 can be a transparent conductive film.

[0047] The lower battery unit 1 has a light-facing surface and a back-light-facing surface arranged opposite each other, as well as a side surface connecting the light-facing surface and the back-light-facing surface. The light-facing surface of the lower battery unit 1 is the surface of the lower battery unit 1 closest to the upper battery unit 3. The number of side surfaces included in the lower battery unit 1 is not specifically limited. For example, if the lower battery unit 1 is a cuboid, then the lower battery unit 1 includes 4 side surfaces.

[0048] Without the insulating layer 2, the coating or wrapping of the thin-film solar cell on its lower side has a significant impact on the side of the lower cell unit 1, easily leading to a short circuit between the upper cell unit 3 and the lower cell unit 1, resulting in low power generation efficiency and poor production yield of the tandem photovoltaic device. (Refer to...) Figure 1As shown, the insulating layer 2 is wrapped around all sides of the lower battery cell 1, so that the coating or coating of the thin-film solar cell on its lower side is located on the insulating layer 2 and does not contact the side of the lower battery cell 1. This avoids direct coating or coating of the thin-film solar cell on the side of the lower battery cell 1, which greatly reduces the short circuit between the upper battery cell 3 and the lower battery cell 1, and can improve the power generation efficiency and production yield of the tandem photovoltaic device. Moreover, in the production process of this tandem photovoltaic device, only the insulating layer needs to be set on the side of the lower battery cell before depositing the upper battery cell on the light-facing surface of the intermediate series structure. Other processes do not need to be changed. There is no need to perform operations such as scribing isolation, edge cutting or cleaning on the side of the tandem photovoltaic device, and no dead zones are created at the edge of the tandem photovoltaic device. The production process is simple and the production cost is low.

[0049] Figure 1 The tandem photovoltaic device shown can have an insulating layer 2 placed on the side of the lower battery cell 1 after the lower battery cell 1 is fabricated and before the upper battery cell 3 is deposited. The thin-film solar cell is coated or coated on the lower side of the cell on the insulating layer 2 without contacting the side of the lower battery cell 1.

[0050] The material of insulating layer 2 is selected from insulating or dielectric materials, which have good electrical insulation properties, and is made by deposition or growth processes.

[0051] Optionally, the edge region of the light-facing side of the lower battery cell 1 is the area near the side of the light-facing side of the lower battery cell 1. The edge region of the backlight side of the lower battery cell 1 is the area near the side of the backlight side of the lower battery cell 1. The insulating layer 2 extends and covers the edge region of the light-facing side of the lower battery cell 1, and / or the insulating layer 2 extends and covers the edge region of the backlight side of the lower battery cell 1, thereby improving the coverage effect of the insulating layer 2 on the lower battery cell 1 and further reducing the risk of short circuit between the upper battery cell 3 and the lower battery cell 1. It should be noted that the size of the edge region of the light-facing side of the lower battery cell 1 covered by the insulating layer 2 is determined according to actual needs. Similarly, the size of the edge region of the backlight side of the lower battery cell 1 covered by the insulating layer 2 is determined according to actual needs.

[0052] Optionally, in the tandem photovoltaic device, the insulating layer 2 further extends and wraps around at least a portion of the side surface of the first layer; this first layer is a layer with charge carrier conductivity in the intermediate series structure 4, or, the first layer is a layer with charge carrier conductivity in the portion of the upper battery cell 3 closest to the intermediate series structure 4. Charge carriers include electrons and holes. The layer with charge carrier conductivity can be: a layer with electron conductivity, and / or a layer with hole conductivity. The coating or wrapping of the thin-film solar cell on its lower side surface is located on the insulating layer and does not contact the side surface of the layer with charge carrier conductivity, avoiding direct coating or wrapping of the thin-film solar cell on the side surface of the layer with charge carrier conductivity, which greatly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

[0053] The insulating layer extends and covers at least a portion of the sides of the first layer, which can be: the insulating layer 2 extends and covers all sides of the entire first layer having charge carrier conductivity. Alternatively, the insulating layer 2 extends and covers all sides of a portion of the first layer having charge carrier conductivity, while the insulating layer 2 is not covered on the remaining portions of the first layer having charge carrier conductivity. Or, the insulating layer 2 can be: the insulating layer 2 covers a portion of the sides of the first layer having charge carrier conductivity, while the insulating layer 2 is not covered on the remaining portions of the first layer having charge carrier conductivity.

[0054] Optionally, the edge region of the light-facing side of the first layer is the region near the side of the light-facing side of the first layer. The edge region of the back-facing side of the first layer is the region near the side of the back-facing side of the first layer. The insulating layer 2 extends and covers the edge region of the light-facing side of the first layer, and / or, the insulating layer 2 extends and covers the edge region of the back-facing side of the first layer. That is, the insulating layer 2 also covers the edge regions of the upper and lower surfaces of the first layer or the edge regions of the interlayer interface. Therefore, the insulating layer 2 has a better coating effect on the layer with charge carrier conduction capability, further improving the power generation efficiency and production yield of the tandem photovoltaic device. It should be noted that the size of the edge region of the insulating layer 2 extending to the light-facing side of the first layer is determined according to actual needs. Similarly, the size of the edge region of the insulating layer 2 extending to the back-facing side of the first layer is determined according to actual needs.

[0055] For example, refer to Figure 2 As shown, Figure 2 A schematic diagram of the structure of a second type of stacked photovoltaic device according to an embodiment of the present invention is shown. Figure 2In this structure, the first layer can be the lower transmission layer 31 of the upper battery cell 3. The insulating layer 2 is provided to cover all sides of the lower battery cell 1, and extends to cover the intermediate series structure 4 and all sides of the lower transmission layer 31 of the upper battery cell 3. The insulating layer 2 also extends to cover all sides of the lower functional film 6, and extends to cover the edge areas of the light-facing side and the back-light-facing side of the lower transmission layer 31. At the same time, the insulating layer 2 also extends to cover the edge areas of the light-facing side and the back-light-facing side of the lower functional film 6.

[0056] Figure 2 The tandem photovoltaic device shown can be fabricated by depositing an insulating layer 2 on the entire side surface of the lower functional film 6, the lower battery cell 1, the intermediate series structure 4, and the lower transport layer 31, as well as the edge regions of the light-facing and back-facing surfaces of the lower transport layer 31, and the edge regions of the back-facing and light-facing surfaces of the lower functional film 6. Then, the substrate 33 of the upper battery cell is deposited on the light-facing surface of the lower transport layer 31. The thin-film solar cell is coated or wrapped around the insulating layer on its lower side surface and does not contact the side surface of the lower transport layer 31, the intermediate series structure 4, the lower battery cell 1, or the lower functional film 6.

[0057] All or part of the sides of the intermediate series structure 4 typically possess carrier conduction capability. (Refer to...) Figure 3 As shown, Figure 3 A schematic diagram of the structure of a third type of stacked photovoltaic device according to an embodiment of the present invention is shown. Optionally, the insulating layer 2 may also extend to cover all sides of the intermediate series structure 4, or the insulating layer 2 may also extend to cover part of the sides of the intermediate series structure 4. Figure 3 As shown, the insulating layer 2 extends beyond the lower battery cell 1, covering all sides, and further extends to cover all sides of the intermediate series structure 4. The thin-film solar cell's coating or wrapping on its lower side is located on the insulating layer, avoiding contact with the sides of the intermediate series structure 4, which has charge carrier conduction capabilities, or minimizing contact area. This significantly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

[0058] Figure 3 The tandem photovoltaic device shown can be fabricated by first placing an insulating layer 2 on the entire side of the lower battery cell 1 and the intermediate series structure 4 after fabricating the lower battery cell 1 and the intermediate series structure 4. Then, an upper battery cell 3 is deposited on the light-facing surface of the intermediate series structure 4. The thin-film solar cell is coated or wrapped around the insulating layer on its lower side, without contacting the side of the lower battery cell 1 and the intermediate series structure 4. This greatly improves the power generation efficiency and production yield of the tandem photovoltaic device. Moreover, the manufacturing process is simple and the production cost is low.

[0059] Figure 4 A schematic diagram of the structure of a fourth type of stacked photovoltaic device according to an embodiment of the present invention is shown. (Refer to...) Figure 4 As shown, the upper battery cell 3 includes a lower transport layer 31 near the lower battery cell 1. The lower transport layer 31 serves to separate and transport charge carriers from the upper battery cell. In this embodiment of the invention, the material of the lower transport layer 31 is not specifically limited. For example, the material of the lower transport layer 31 can be titanium oxide. The insulating layer 2 also extends and wraps around all sides of the lower transport layer 31. Alternatively, the insulating layer 2 also extends and wraps around a portion of the sides of the lower transport layer 31. The coating or wrapping of the thin-film solar cell on its lower side is located on the insulating layer, and does not contact the side of the lower transport layer 31, which has charge carrier conduction capabilities, or has a small contact area with it, thus greatly improving the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low. Figure 4 The tandem photovoltaic device shown has an insulating layer 2 that wraps all sides of the lower battery cell 1, as well as all sides of the intermediate series structure 4, and all sides of the upper battery cell 3 near the lower transmission layer 31 of the lower battery cell 1.

[0060] Figure 4 The tandem photovoltaic device shown can have an insulating layer 2 formed on the entire side of the lower battery cell 1, intermediate series structure 4, and lower transmission layer 31, after the lower battery cell 1, intermediate series structure 4, and lower transmission layer 31. Then, the substrate 33 of the upper battery cell is deposited on the light-facing surface of the lower transmission layer 31. The thin-film solar cell is coated or wrapped around the insulating layer on its lower side, without contacting the side of the lower battery cell 1, intermediate series structure 4, and lower transmission layer 31. This significantly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

[0061] It should be noted that, in addition to covering all sides of the lower battery unit 1, the insulating layer 2 may not cover the sides of the intermediate series structure 4, but may instead cover all or part of the sides of the lower transmission layer 31 of the upper battery unit 3 near the lower battery unit 1.

[0062] The lower transmission layer 31 included in the upper battery cell 3 can be one or more layers shared by the upper battery cell 3 and the intermediate series structure 4. In this embodiment of the invention, no specific limitation is made. An intermediate series structure 4 may not be specifically provided between the upper battery cell 3 and the lower battery cell 1; some layers of the upper battery cell 3 can simultaneously perform the function of the intermediate series structure 4. In this embodiment of the invention, no specific limitation is made.

[0063] Optionally, the upper battery cell includes a buffer layer that serves as a lattice fitter. An insulating layer is also wrapped around all sides of the buffer layer, or partially wrapped around its sides. The thin-film solar cell's coating or wrapping on its lower side is located on the insulating layer, avoiding contact with the sides of the buffer layer which has charge carrier conductivity, or minimizing contact area. This significantly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

[0064] Optional, refer to Figure 2 As shown, the tandem photovoltaic device also includes a lower functional film 6 located on the back surface of the lower battery cell. The lower functional film, located on the back surface of the lower battery cell, functions to collect and transport charge carriers, passivate the surface, and reduce reflection. The lower functional film 6 includes a back transport layer, which is located on the back surface of the lower battery cell and functions to transport charge carriers. The insulating layer 2 extends and wraps around all sides of the back transport layer, or the insulating layer 2 extends and wraps around part of the sides of the back transport layer. The thin-film solar cell's coating or wrapping on its lower side is located on the insulating layer and does not contact the sides of the back transport layer with charge carrier conduction capability, or the contact area with it is small, which greatly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low. The lower functional film 6 may also include a back passivation layer and a back anti-reflection layer, etc.

[0065] For example, refer to Figure 5 As shown, Figure 5 A schematic diagram of the structure of the fifth type of stacked photovoltaic device according to an embodiment of the present invention is shown. The lower functional film 6 includes a back transmission layer, and the insulating layer 2 extends to wrap around all sides of the back transmission layer. At the same time, the insulating layer 2 also extends to the back surface of the lower functional film 6 and extends to cover the light-facing surface of the intermediate series structure 4. Figure 5 In the tandem photovoltaic device shown, the light-facing and back-light-facing surfaces of the lower battery cell 1 are both light-trapping structures, and the remaining layers are adapted to the light-trapping structures of the light-facing and back-light-facing surfaces of the lower battery cell 1. Figure 5 The tandem photovoltaic device shown can be fabricated by depositing an insulating layer 2 on the entire side surface of the lower functional film 6, the lower battery cell 1, and the intermediate series structure 4, as well as the edge region of the light-facing side of the intermediate series structure 4 and the edge region of the backlight side of the lower functional film 6, after fabricating the lower functional film 6, the lower battery cell 1, and the intermediate series structure 4. Then, the upper battery cell 3 is deposited on the light-facing side of the intermediate series structure 4. The thin-film solar cell is coated or wrapped around the insulating layer on its lower side surface, without contacting the sides of the lower functional film 6, the lower battery cell 1, and the intermediate series structure 4. This significantly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

[0066] Optional, refer to Figure 1 As shown, the thickness d of the insulating layer 2 is the dimension parallel to the light-facing surface of the upper battery cell 1. The thickness d of the insulating layer 2 is greater than or equal to 10 nm. The insulating layer 2 is a single or multi-layer structure. The insulating layer 2 with the above-mentioned dimensions has good insulation effect. It only needs a thickness at the nm level to achieve excellent electrical insulation effect. In tandem photovoltaic devices, the insulating layer 2 occupies little space, which is conducive to making full use of the area within the tandem photovoltaic device.

[0067] Optional, refer to Figure 6 As shown, Figure 6 A schematic diagram of the sixth type of tandem photovoltaic device according to an embodiment of the present invention is shown. An insulating layer 2 is disposed on the light-facing surface of the lower battery cell 1. The insulating layer 2 on the light-facing surface of the lower battery cell 1 has at least one through-hole 41, each through-hole 41 being filled with conductive material. The insulating layer 2 on the light-facing surface of the lower battery cell 1 and the conductive material filled in the through-holes 41 form an intermediate series structure 4. The conductive material in the through-holes 41 is a metallic structure or a transparent conductive material. Therefore, the area of ​​the light-facing surface of the lower battery cell 1, excluding the through-holes 41, and the sides of the lower battery cell 1 are all covered with the insulating layer 2. The thin-film solar cell is coated or coated around its lower side surface on the insulating layer, which greatly improves the power generation efficiency and production yield of the tandem photovoltaic device. Furthermore, the manufacturing process is simple and the production cost is low.

[0068] Optionally, the insulation strength of insulation layer 2 is greater than or equal to 3MV / cm, and the insulation effect of insulation layer 2 is good.

[0069] Optionally, if the lower battery cell 1 is a crystalline silicon solar cell, the insulating layer 2 is silicon oxide (such as SiO2). x ) layer, silicon nitride (such as SiN) x ) layer, silicon oxyfluoride (such as SiOF) layer, silicon oxycarbonate (such as SiOC) layer, aluminum oxide (such as Al2O3) layer, aluminum fluoride (such as AlF) layer x The insulating layer 2 is selected from at least one of the following: an aluminum oxynitride (e.g., AlON) layer, and a magnesium fluoride (e.g., MgF2) layer. The above materials exhibit good electrical insulation properties, and the preparation process of the insulating layer 2 is similar to that of the passivation layer in a crystalline silicon solar cell. Existing production processes or equipment for the passivation layer of crystalline silicon solar cells can be directly used, without the need for additional equipment or processes, thus simplifying the process. It should be noted that the value of x in the chemical formula can be selected appropriately by those skilled in the art based on the actual situation.

[0070] For example, if the lower cell unit 1 is a crystalline silicon solar cell, the insulating layer 2 is a single layer of silicon nitride material with a thickness of 100 nm. As another example, if the lower cell unit 1 is a crystalline silicon solar cell, the insulating layer 2 is a single layer of aluminum oxide material with a thickness of 30 nm.

[0071] Optionally, when the lower battery cell 1 is a crystalline silicon solar cell, the insulating layer 2 includes a silicon oxide layer, an aluminum oxide layer, and a silicon nitride layer stacked sequentially. The silicon oxide layer is in contact with the lower battery cell. That is, during the fabrication of the insulating layer 2, the silicon oxide layer is first deposited on the side of the lower battery cell 1, then the aluminum oxide layer, and finally the silicon nitride layer. This insulating layer not only provides good electrical insulation but also utilizes existing crystalline silicon solar cell fabrication processes. Furthermore, the order of the three layers in the insulating layer conforms to the order of crystalline silicon solar cell fabrication, thus simplifying the fabrication process and increasing efficiency. The thickness of the three layers is not specifically limited; the total thickness of the three layers can be greater than or equal to 10 nm. For example, a silicon oxide layer of approximately 2 nm, an aluminum oxide layer of approximately 30 nm, and a silicon nitride layer of approximately 100 nm can all be fabricated using a deposition method.

[0072] The present invention also provides a method for manufacturing a multilayer photovoltaic device, which specifically includes the following steps:

[0073] Step S1, providing a lower battery cell; the lower battery cell has a light-facing surface and a back-light surface disposed opposite to each other, and a side surface connecting the light-facing surface and the back-light surface.

[0074] Step S2: Obtain an insulating layer at least covering the sides of the lower battery cell by deposition or growth.

[0075] Step S3: Prepare an intermediate series structure on the light-facing surface of the lower battery cell.

[0076] Step S4: Deposit the upper battery cell on the light-facing surface of the intermediate series structure; the lower battery cell is a thin-film solar cell.

[0077] The growth method can be epitaxial growth, and this is not specifically limited in this embodiment of the invention. The fabrication method of this tandem photovoltaic device can refer to the relevant description of the aforementioned tandem photovoltaic device, and has the same or similar beneficial effects as the aforementioned tandem photovoltaic device. To avoid repetition, it will not be described again here.

[0078] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A stacked photovoltaic device, characterized by, The laminated photovoltaic device comprises: an upper layer cell unit, a lower layer cell unit, and an intermediate series structure between the upper layer cell unit and the lower layer cell unit; The upper layer cell unit is a thin film solar cell; The lower layer cell unit has a light-receiving surface and a back surface arranged oppositely, and a side surface connecting the light-receiving surface and the back surface; The laminated photovoltaic device further comprises an insulating layer wrapped at least on the side surface of the lower layer cell unit; The lower layer cell unit is a crystalline silicon solar cell; The upper layer cell unit is located on the light-receiving side of the lower layer cell unit; At least part of the structure of the upper layer cell unit is wrapped outside the insulating layer; The laminated photovoltaic device further comprises a lower functional film on the back surface of the lower layer cell unit, and the lower functional film comprises a back surface transport layer; The insulating layer further extends and wraps at least part of the side surface of the back surface transport layer; The insulating layer is at least one of a silicon oxide layer, a silicon nitride layer, a silicon oxyfluoride layer, a silicon oxyfluoride layer, an aluminum oxide layer, an aluminum fluoride layer, an aluminum oxynitride layer, and a magnesium fluoride layer.

2. The tandem photovoltaic device of claim 1, wherein, The insulating layer further extends and wraps at least part of the side surface of a first layer; the first layer is a layer having carrier conduction capability in the intermediate series structure, or the first layer is a layer having carrier conduction capability in the part of the upper layer cell unit close to the intermediate series structure.

3. The tandem photovoltaic device according to claim 1 or 2, characterized in that, The insulating layer extends and covers the edge region of the light-receiving surface of the lower layer cell unit; And / or, the insulating layer extends and covers the edge region of the back surface of the lower layer cell unit.

4. The tandem photovoltaic device of claim 2, wherein, The insulating layer extends and covers the edge region of the light-receiving surface of the first layer; And / or, the insulating layer extends and covers the edge region of the back surface of the first layer.

5. The tandem photovoltaic device of claim 2, wherein, The first layer is a lower transport layer close to the lower layer cell unit.

6. The tandem photovoltaic device of claim 2, wherein, The upper layer cell unit comprises a buffer layer; The insulating layer further extends and wraps at least part of the side surface of the buffer layer.

7. The tandem photovoltaic device of claim 1 or 2, wherein, The thickness of the insulating layer is greater than or equal to 10 nm; the insulating layer is a single layer or a multi-layer structure.

8. The tandem photovoltaic device of claim 1 or 2, wherein, The insulating layer is wrapped on the light-receiving surface of the lower layer cell unit; The insulating layer wrapped on the light-receiving surface of the lower layer cell unit has at least one through hole, and each through hole is filled with a conductive material; the insulating layer wrapped on the light-receiving surface of the lower layer cell unit and the conductive material filled in the through hole form the intermediate series structure.

9. The tandem photovoltaic device of claim 1 or 2, wherein, The insulating strength of the insulating layer is greater than or equal to 3 MV / cm.

10. The layered photovoltaic device of claim 1, wherein, The side surface insulating layer comprises a silicon oxide layer, an aluminum oxide layer, and a silicon nitride layer stacked in sequence, wherein the silicon oxide layer is in contact with the lower layer cell unit.

11. A method for producing a stacked photovoltaic device, characterized by, The method comprises the following steps: providing a lower layer cell unit; the lower layer cell unit has a light-receiving surface and a back surface arranged oppositely, and a side surface connecting the light-receiving surface and the back surface; the lower layer cell unit is a crystalline silicon solar cell; obtaining an insulating layer wrapped at least on the side surface of the lower layer cell unit by deposition or growth; preparing an intermediate series structure on the light-receiving surface of the lower layer cell unit; depositing an upper layer cell unit on the light-receiving surface of the intermediate series structure; the upper layer cell unit is a thin film solar cell; At least part of a structure of the upper cell is wrapped outside the insulating layer; The stacked photovoltaic device further comprises a lower functional film on a back light surface of the lower cell, and the lower functional film comprises a back transport layer; The insulating layer further extends to wrap at least part of a side surface of the back transport layer; The insulating layer is at least one of a silicon oxide layer, a silicon nitride layer, a silicon oxyfluoride layer, a silicon oxy-carbon layer, an aluminum oxide layer, an aluminum fluoride layer, an aluminum oxynitride layer, and a magnesium fluoride layer.

Images