Laminated solar cell

Abstract

The invention relates to an optimized laminated solar cell structure which improves the stability and reliability of a cell while reducing the manufacturing cost. The solar cell is composed of a crystalline silicon cell layer, a perovskite cell layer and a middle layer, the crystalline silicon cell layer forms an efficient PN junction through doping, and the back face and the front face of the crystalline silicon cell layer comprise a multi-layer structure so as to optimize photon absorption and current transmission. The design of a strip-shaped area on the front face of the crystalline silicon cell layer effectively reduces interface recombination and improves photoelectric conversion efficiency, the middle layer is made of a high-light-transmittance transparent material, light reflection is reduced and light absorption is enhanced through the refractive index gradient design, the perovskite cell layer serves as a top layer, the perovskite cell layer and the crystalline silicon cell layer form complementation and jointly cover a wide spectrum, and the light energy utilization rate is improved. In addition, the silicon nitride layer is used as a passivation layer and an anti-reflection layer, and the grid-shaped design of the grid line electrode further improves the photoelectric performance and the stability of the cell. The invention further provides a solar cell module comprising the laminated solar cell, and the solar cell module has better module performance.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a stacked solar cell. Background Art

[0002] With the continuous growth of global energy demand and the enhancement of environmental protection awareness, the development of efficient, stable and cost-controlled solar cell technology has become a hot topic in scientific research and industry. As an important development direction in the field of solar cells, tandem solar cells have attracted widespread attention for their ability to significantly improve the efficiency of photoelectric conversion. Tandem solar cells achieve more effective use of sunlight by stacking multiple semiconductor materials with different bandgap widths together, each absorbing and utilizing energy in different bands of the solar spectrum.

[0003] Although tandem solar cells have made progress in photoelectric conversion efficiency, their further development still faces many challenges. First, how to form a passivation contact structure on the front is to improve the performance of tandem solar cells. Although a variety of passivation materials and technologies have been applied to the surface of solar cells, such as SiO2 / TiO2 / ZnO tandem structures, how to further optimize these structures to achieve better passivation effects and higher optical utilization still requires further research. Secondly, the preparation process of tandem solar cells is relatively complex and costly, which limits their large-scale commercial application. Therefore, the development of more efficient and low-cost preparation processes, such as the use of atomic layer deposition technology to prepare passivation films such as aluminum oxide, and the optimization of the deposition sequence and parameters of the tandem structure, has become the focus of current research. Finally, the long-term stability and reliability of tandem solar cells are also urgent issues to be solved. Due to the presence of multiple interfaces and interlayer connections in the tandem structure.

[0004] Therefore, how to reduce composite losses and improve battery stability and life through interface passivation technology is another important direction of current research. Summary of the invention

[0005] The purpose of the present application is to provide a laminated solar cell, which can improve the cell conversion efficiency and improve the stability and reliability of the cell by optimizing the structure and distribution of each layer. The laminated solar cell of the present application includes a crystalline silicon cell layer, a perovskite cell layer, and an intermediate layer arranged on the crystalline silicon cell layer and the perovskite cell layer;

[0006] The crystalline silicon cell layer includes a silicon substrate, a PN junction is formed in the silicon substrate by doping, a first tunneling layer, a first doped polysilicon layer and a first anti-reflection layer are included on the back side of the silicon substrate, and a second tunneling layer and a second doped polysilicon layer are formed in partitions on the front side of the silicon substrate;

[0007] The intermediate layer comprises a first insulating layer, a first connecting layer, a second insulating layer and a first conductive layer, the first insulating layer fills the area on the front side of the silicon substrate where the second tunneling layer and the second doped polysilicon layer are not formed, the upper surface of the first insulating layer is flush with the upper surface of the second doped polysilicon layer, the first connecting layer comprises conductive areas connecting different positions, the second insulating layer comprises through holes, the through holes are filled with conductive material, and the first conductive layer is electrically connected to the conductive areas in the first connecting layer through the through holes;

[0008] The perovskite cell layer is formed on the first conductive layer.

[0009] In one embodiment, the region where the second tunneling layer and the second doped polysilicon layer are formed on the front surface of the silicon substrate is a strip-shaped region.

[0010] In one of the embodiments, the strip-shaped regions are distributed in parallel and are parallel to the scribing direction of the perovskite cell layer.

[0011] In one embodiment, the intermediate layer is a transparent material layer.

[0012] In one embodiment, the perovskite cell layer includes an electron transport layer, a photoelectric conversion layer, a hole transport layer and a front electrode layer, and the perovskite cell layer is divided into a plurality of regions by scribing.

[0013] In one of the embodiments, a silicon nitride layer is formed on the surface of the crystalline silicon cell layer and the perovskite cell layer as a whole.

[0014] In one of the embodiments, the area of ​​the region where the second tunneling layer and the second doped polysilicon layer are formed is 20%-25% of the front surface area.

[0015] In one embodiment, the refractive indexes of the first insulating layer, the first connecting layer, the second insulating layer and the first conductive layer increase sequentially from top to bottom.

[0016] In one of the embodiments, the back side of the crystalline silicon cell layer and the front side of the perovskite cell layer further include gate line electrodes.

[0017] In addition, the present application also provides a solar cell assembly, which includes the aforementioned stacked solar cell.

[0018] Compared with the prior art, the present application has the following beneficial effects: The stacked design of the present application fully utilizes the respective advantages of crystalline silicon cells and perovskite cells in spectral absorption, and realizes efficient photoelectric conversion in a wide spectral range. The crystalline silicon cell layer effectively absorbs infrared spectrum energy, while the perovskite cell layer efficiently utilizes visible light and near-infrared spectrum. The synergistic effect of the two significantly improves the photoelectric conversion efficiency of the overall cell. On the front side of the crystalline silicon cell layer, the second tunneling layer and the second doped polysilicon layer formed by partitioning realize a local passivation contact structure, effectively reducing interface recombination losses and improving the collection efficiency of photogenerated carriers. It not only enhances the electrical performance of the battery, but also optimizes the propagation path of light inside the battery, further improving the photoelectric conversion efficiency.

[0019] The middle layer includes a combination of a first insulating layer, a first connecting layer, a second insulating layer and a first conductive layer, which not only ensures the effective transmission of interlayer current, but also isolates direct contact between different materials to prevent the adverse effects of interface reactions on battery performance. In addition, the selection of transparent materials and the gradient design of the refractive index reduce the reflection and scattering of light between layers, improve the utilization rate of light, and thus enhance the stability and reliability of the battery. The stacked solar cell provided in the present application has a flexible and changeable structural design, and the area ratio of the crystalline silicon cell layer and the perovskite cell layer, the layout of the strip area, etc. can be adjusted according to actual needs to adapt to different lighting conditions and application scenarios. This flexibility makes the stacked solar cell of the present application have a wider application prospect. The stacked solar cell of the present application has been optimized in improving the photoelectric conversion efficiency, stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a stacked solar cell in one embodiment of the present application;

[0021] Figure 2 It is a schematic diagram of the structure of the middle layer of a stacked solar cell in one embodiment of the present application.

[0022] Explanation of reference numerals: 100, crystalline silicon cell layer; 200, perovskite cell layer; 300, intermediate layer; 310, first insulating layer; 320, first connecting layer; 330, second insulating layer; 340, first conductive layer. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] With their unique advantages, tandem solar cells have shown great potential in improving photoelectric conversion efficiency and enhancing cell stability and reliability. Tandem solar cells achieve more effective use of energy in different bands of the solar spectrum by stacking semiconductor materials with different bandgap widths, thus breaking through the limitations of single-material solar cells in conversion efficiency. This application revolves around the core technical features of tandem solar cells and deeply explores its improvements in material selection, structural design, process optimization, etc. From the synergistic effect of the crystalline silicon cell layer 100 and the perovskite cell layer 200, to the fine design of the multi-layer structure in the intermediate layer 300, to the innovative application of the local passivation contact structure, the technical solution of this application will be introduced in detail below. Please refer to Figure 1 to Figure 2As shown, a stacked solar cell in a preferred embodiment of the present application optimizes the structure of the stacked solar cell, can reduce the manufacturing cost, and also improves the stability and reliability of the battery. Specifically, it includes a crystalline silicon cell layer 100, a perovskite cell layer 200, and an intermediate layer 300 arranged on the crystalline silicon cell layer 100 and the perovskite cell layer 200. The crystalline silicon cell layer 100 includes a silicon substrate, a PN junction is formed in the silicon substrate by doping, a first tunneling layer, a first doped polycrystalline silicon layer and a first anti-reflection layer are included on the back side of the silicon substrate, and a second tunneling layer and a second doped polycrystalline silicon layer formed by partitions are included on the front side of the silicon substrate.

[0027] The intermediate layer 300 includes a first insulating layer 310, a first connecting layer 320, a second insulating layer 330 and a first conductive layer 340. The first insulating layer 310 fills the area on the front side of the silicon substrate where the second tunneling layer and the second doped polysilicon layer are not formed. The upper surface of the first insulating layer 310 is flush with the upper surface of the second doped polysilicon layer. The first connecting layer 320 includes conductive areas connecting different positions. The second insulating layer 330 includes through holes filled with conductive material. The first conductive layer 340 is electrically connected to the conductive areas in the first connecting layer 320 through the through holes. The perovskite battery layer 200 is formed on the first conductive layer 340.

[0028] The crystalline silicon cell layer 100 is used as the bottom layer, and its structure is complex and efficient. The silicon substrate is used as the basis, and a PN junction is formed through a doping process. The first tunneling layer, the first doped polysilicon layer and the first anti-reflection layer are arranged on the back of the silicon substrate to optimize the absorption and utilization of photons, reduce the reflection loss of light, and improve the photoelectric conversion efficiency. The front of the silicon substrate adopts a partitioned second tunneling layer and a second doped polysilicon layer. This local passivation contact structure effectively reduces the interface recombination and further improves the battery performance. The first insulating layer 310 accurately fills the area where the second tunneling layer and the second doped polysilicon layer are not formed on the front of the silicon substrate, ensuring the insulation between the layers. At the same time, the upper surface of the first insulating layer 310 is flush with the upper surface of the second doped polysilicon layer, providing an interface for subsequent stacking. The first connecting layer 320 is embedded with conductive areas connecting different positions, realizing effective current transmission. The through-hole design in the second insulating layer 330 enables the first conductive layer 340 to seamlessly connect with the conductive area in the first connecting layer 320 by filling the conductive material, ensuring the reliability and stability of the electrical connection between the layers.

[0029] The perovskite cell layer 200, as the top layer, fully utilizes its excellent light absorption ability and high conversion efficiency characteristics, and is directly formed on the first conductive layer 340, complementing the crystalline silicon cell layer 100, and together covering a wider range of the solar spectrum to maximize the use of light energy.

[0030] Specifically, the area where the second tunneling layer and the second doped polysilicon layer are formed on the front side of the silicon substrate is a strip area. The strip area can not only guide the path of photons more effectively and reduce the reflection and scattering of light on the interface, but also control the flow path of current in the silicon substrate through its shape, thereby optimizing the current distribution and reducing the resistance loss. The arrangement and spacing of the strip area are also calculated to ensure the maximum utilization of the incident light and minimize the loss of light inside the battery. The design of the strip area can more effectively capture and absorb the incident light, especially for light of a specific wavelength. This design can guide the light to be reflected and scattered multiple times in the strip area, thereby increasing the optical path and improving the light absorption efficiency. The strip area serves as a transmission channel for the current, and its shape and arrangement can guide the current to be evenly distributed in the silicon substrate, reduce current congestion and hot spot effects, and improve the current output capacity of the battery. The design of the strip area also helps to reduce the carrier loss caused by interface recombination and improve the stability of the battery. The design of the strip area has a certain flexibility and can be adjusted according to different lighting conditions and battery sizes.

[0031] Specifically, the strip regions are distributed in parallel, parallel to the scribing direction of the perovskite cell layer 200. This design not only optimizes the collection efficiency of photogenerated carriers, but also significantly improves the overall photoelectric conversion performance of the cell. By precisely controlling the width, spacing and material properties of the strip regions, fine regulation of light absorption, charge separation and transmission processes is achieved, thereby maximizing the use of incident light energy and reducing energy loss. The parallel layout of the strip regions and the scribing direction ensures that photogenerated carriers can be effectively collected along the shortest path, reducing the recombination loss during the transmission process, thereby improving the photoelectric conversion efficiency, and helping to achieve higher open circuit voltage and short circuit current density. It is one of the methods to improve the performance of perovskite solar cells. The strip regions may serve as charge transfer channels or interface modification layers, and their layout parallel to the scribing direction helps to form an efficient charge transfer network, promote the separation and transmission of electrons and holes, reduce interface resistance, and improve charge collection efficiency. By rationally designing the material composition and optical properties of the strip regions, selective absorption or scattering of light of a specific wavelength can be achieved, further enhancing the perovskite layer's ability to capture light energy.

[0032] Specifically, the intermediate layer 300 is a transparent material layer. The intermediate layer 300 is made of a transparent material with high light transmittance, which ensures that sunlight can fully penetrate into the active layer of the perovskite cell, thereby improving the efficiency of the cell in capturing light energy. The low absorption loss characteristic of the transparent material layer means that it consumes almost no light energy during light transmission, thereby reducing unnecessary energy loss and improving the overall energy conversion efficiency of the cell.

[0033] Specifically, the perovskite battery layer 200 includes an electron transport layer, a photoelectric conversion layer, a hole transport layer and a front electrode layer, and the perovskite battery layer 200 is divided into multiple regions by scribing. The design of the multi-layer structure ensures that the perovskite battery layer 200 can efficiently absorb sunlight and convert it into electrical energy. The electron transport layer promotes the export of photogenerated electrons to the external circuit, while the hole transport layer accelerates the transmission and collection of holes. The two work together to reduce charge recombination losses, thereby improving the photoelectric conversion efficiency. By dividing the perovskite battery layer 200 into multiple regions by scribing, photogenerated carriers can be guided to transmit along a specific path, reducing their random diffusion and recombination inside the battery, which helps to shorten the charge transmission distance, improve the charge collection efficiency, and reduce energy loss. The scribing process not only optimizes the charge transmission path, but also helps to alleviate the thermal stress that may be generated by the battery during long-term operation. By dividing the battery layer into multiple regions, the risk of local overheating can be reduced and the overall stability and reliability of the battery can be improved. The divided sub-areas can be independently regulated according to lighting conditions, such as by adjusting the size, shape or position of the sub-areas to optimize light absorption and charge collection efficiency. This flexibility enables perovskite cells to better adapt to different lighting environments and improve their power generation performance under complex lighting conditions.

[0034] Specifically, a silicon nitride layer is formed on the surface of the crystalline silicon battery layer 100 and the perovskite battery layer 200 as a whole. In order to further improve the photoelectric conversion efficiency of the battery and protect the internal structure of the battery from the influence of the external environment, the surface of the crystalline silicon battery layer 100 and the perovskite battery layer 200 is carefully covered with a uniform and dense silicon nitride layer as a whole. This silicon nitride layer not only effectively reduces the interface state density and recombination center as a passivation layer, but also significantly improves the battery's ability to absorb light as an anti-reflection layer. By precisely controlling the thickness and refractive index of the silicon nitride layer, it is possible to achieve optimal absorption of light of different wavelengths, so that the battery can maintain a high light absorption efficiency in a wider spectral range.

[0035] Specifically, the area of ​​the second tunneling layer and the second doped polysilicon layer is 20%-25% of the front surface area. By limiting the area of ​​the second tunneling layer and the second doped polysilicon layer to 20%-25% of the front surface area, it is possible to maximize the absorption of light by the active layer of the battery (such as the perovskite layer or the crystalline silicon layer) while ensuring sufficient charge collection efficiency, reduce the shielding of light by the opaque electrode material, and improve the overall light capture ability of the battery. Due to the reduction in the area ratio of the electrode material, more light can be directly irradiated onto the photoelectric conversion layer and then converted into electrical energy. At the same time, the precisely controlled electrode area ensures that the charge can be efficiently transferred from the photoelectric conversion layer to the external circuit, reducing the charge recombination loss that may be caused by the excessive electrode area. By adjusting the area ratio of the electrode area, the design of the battery can be optimized according to specific application scenarios and needs. For example, in areas with good lighting conditions, the electrode area can be appropriately reduced to improve the photoelectric conversion efficiency; while in areas with poor lighting conditions, the electrode area may need to be increased to ensure sufficient charge collection efficiency.

[0036] Specifically, the refractive index of the first insulating layer 310, the first connecting layer 320, the second insulating layer 330 and the first conductive layer 340 increases from top to bottom. By increasing the refractive index of each layer of material from top to bottom, a refractive index gradient is created, which helps the light gradually adapt to the change of the refractive index when passing through each layer, reduces the reflection on the interface between the layers, and improves the penetration rate of the light inside the battery, so that more light energy can be absorbed and utilized by the photoelectric conversion layer. Due to the reduction of light reflection, more light can penetrate deep into the battery and interact with the photoelectric conversion layer, thereby increasing the amount of photogenerated carriers generated, which is crucial to improving the photoelectric conversion efficiency of the battery. Although the refractive index gradient design mainly focuses on the optimization of optical properties, it also indirectly promotes the transmission of charges inside the battery. By reducing light reflection and enhancing light absorption, more photogenerated carriers are generated and injected into the corresponding transmission layer, which helps to reduce charge recombination losses and improve charge collection efficiency. The refractive index gradient design also helps to reduce local overheating caused by light reflection and improve the performance stability of the battery in a high temperature environment. By optimizing the refractive index matching of each layer of material, the stress concentration problem caused by the difference in thermal expansion coefficient of the material can also be reduced.

[0037] Specifically, the back side of the crystalline silicon cell layer 100 and the front side of the perovskite cell layer 200 also include gate electrodes, which are made of highly conductive materials such as silver or copper and are distributed on the cell surface in a grid pattern, thereby ensuring maximum light transmittance and achieving efficient collection of photogenerated carriers. The grid design of the gate electrodes enables them to cover most areas of the cell surface, thereby effectively collecting photogenerated carriers generated by the photoelectric conversion layer. This high current collection mechanism reduces the recombination loss of charge inside the cell and improves the short-circuit current density and fill factor of the cell.

[0038] In addition, the present application also provides a solar cell module, which includes the aforementioned stacked solar cell. The module not only inherits the significant advantages of the stacked solar cell in terms of photoelectric conversion efficiency, energy density and stability, but also achieves higher power output through ingenious structural design and system integration.

[0039] As can be seen from the foregoing, the present application proposes a new laminated solar cell structure, which improves the stability and reliability of the battery while reducing the manufacturing cost. The laminated solar cell consists of a crystalline silicon cell layer, a perovskite cell layer and a carefully designed intermediate layer, forming an efficient and coordinated energy conversion system. The crystalline silicon cell layer is used as the bottom layer, and the PN junction doping process ensures efficient photoelectric conversion performance. The first tunneling layer, the first doped polysilicon layer and the first anti-reflection layer are arranged on the back, which effectively improves the absorption efficiency of photons and reduces light reflection losses. The partition design on the front introduces the second tunneling layer and the second doped polysilicon layer. This local passivation contact structure reduces the interface recombination and further improves the overall performance of the battery. In particular, the design of the front strip area not only optimizes the transmission path of the photogenerated carriers, but also controls the current distribution through its shape and arrangement, reduces resistance losses, and improves the current output capacity of the battery.

[0040] The middle layer is made of transparent materials with high light transmittance, ensuring that sunlight can fully penetrate into the perovskite cell layer, improving the efficiency of light energy capture. At the same time, the fine structural design inside the middle layer, including the first insulating layer, the first connecting layer, the second insulating layer and the first conductive layer, reduces the reflection of light at the interface between the layers through the optimization of the refractive index gradient, enhances the penetration depth of light, and further improves the photoelectric conversion efficiency. The combination of through holes and conductive materials ensures the reliability and stability of the electrical connection between the layers.

[0041] As the top layer, the perovskite cell layer fully utilizes its excellent light absorption capacity and high conversion efficiency characteristics, complementing the crystalline silicon cell layer, and together covering a wider range of solar spectrum, achieving maximum utilization of light energy. Through multi-layer structure design and scribing process, the perovskite cell layer not only improves the photoelectric conversion efficiency, but also enhances the stability and reliability of the cell.

[0042] The above is only a specific implementation of the present application, and any other improvements made based on the concept of the present application are deemed to be within the protection scope of the present application.

Claims

1. A stacked solar cell, characterized in that: It comprises a crystalline silicon cell layer (100), a perovskite cell layer (200), and an intermediate layer (300) arranged on the crystalline silicon cell layer (100) and the perovskite cell layer (200); The crystalline silicon cell layer (100) comprises a silicon substrate, a PN junction is formed in the silicon substrate by doping, a first tunneling layer, a first doped polysilicon layer and a first anti-reflection layer are included on the back side of the silicon substrate, and a second tunneling layer and a second doped polysilicon layer are formed in partitions on the front side of the silicon substrate; The intermediate layer (300) comprises a first insulating layer (310), a first connecting layer (320), a second insulating layer (330) and a first conductive layer (340); the first insulating layer (310) fills a region on the front side of the silicon substrate where the second tunneling layer and the second doped polysilicon layer are not formed; the upper surface of the first insulating layer (310) is flush with the upper surface of the second doped polysilicon layer; the first connecting layer (320) comprises conductive regions connecting different positions; the second insulating layer (330) comprises a through hole, the through hole is filled with a conductive material; the first conductive layer (340) is electrically connected to the conductive region in the first connecting layer (320) through the through hole; The perovskite cell layer (200) is formed on the first conductive layer (340).

2. The tandem solar cell according to claim 1, characterized in that: The area where the second tunneling layer and the second doped polysilicon layer are formed on the front surface of the silicon substrate is a strip-shaped area.

3. The tandem solar cell according to claim 2, characterized in that: The strip-shaped regions are distributed in parallel and are parallel to the scribing direction of the perovskite cell layer (200).

4. The tandem solar cell according to claim 1, characterized in that: The intermediate layer (300) is a transparent material layer.

5. The tandem solar cell according to claim 1, characterized in that: The perovskite cell layer (200) comprises an electron transport layer, a photoelectric conversion layer, a hole transport layer and a front electrode layer, and the perovskite cell layer (200) is divided into a plurality of regions by scribing.

6. The tandem solar cell according to claim 5, characterized in that: A silicon nitride layer is also formed on the entire surface of the crystalline silicon cell layer (100) and the perovskite cell layer (200).

7. The tandem solar cell according to claim 1, characterized in that: The area of ​​the region where the second tunneling layer and the second doped polysilicon layer are formed is 20%-25% of the front surface area.

8. The tandem solar cell according to claim 1, characterized in that: The refractive indexes of the first insulating layer (310), the first connecting layer (320), the second insulating layer (330) and the first conductive layer (340) increase sequentially from top to bottom.

9. The tandem solar cell according to claim 1, characterized in that: The back side of the crystalline silicon cell layer (100) and the front side of the perovskite cell layer (200) also include gate line electrodes.

10. A solar cell module, characterized in that: The invention comprises a stacked solar cell as claimed in any one of claims 1 to 9.

Images