Patent Description:
With the gradual aggravation of energy crisis and environmental pollution, human's demand for renewable energy is increasing. Solar energy has advantages of safety, pollution-free, and not being limited by geographical conditions, and is the most widely used and most promising renewable energy. In various technologies for effectively utilizing the solar energy, photovoltaic power generation is undoubtedly one of the most promising directions. Perovskite solar cell has advantages of high efficiency, solution preparation, low cost, and the like. The photoelectric conversion efficiency of the perovskite solar cell is close to that of a silicon-based solar cell. With the in-depth research on the silicon-based solar cell, photoelectric conversion efficiency of the silicon-based solar cell is close to maximum theoretical efficiency. Therefore, improving the photoelectric conversion efficiency of the solar cell has become the key to the development of this field.

A tandem cell technology is one of the most effective ways to improve the photoelectric conversion efficiency of the solar cell. The perovskite material have very strong absorption in a visible light region of <NUM> to <NUM>, while silicon absorbs near-infrared light of <NUM> to <NUM>, so a silicon-perovskite tandem solar cell composed of a perovskite cell and a silicon cell has been more and more researched, and has achieved higher efficiency than a monocrystalline silicon cell or a perovskite cell. However, due to poor conductivity of an existing silicon-perovskite tandem solar cell, improvement of the solar-energy efficiency of the solar cell is restricted.

Therefore, it is expected to further improve the conductivity of the silicon-perovskite tandem solar cell to improve the photoelectric conversion efficiency of the solar cell.

<NPL>, discloses a perovskite-silicon tandem solar cell including a front TCO and grid electrode. The grid electrode is made of Ag. <NPL>, discloses a planar perovskite solar cell including an ITO/Ag grid/AZO tri-layered electrode on an electron transport layer of ZnO nanoparticles.

In view of the above, the present disclosure provide a solar cell as defined in claim <NUM>, a manufacturing method thereof as defined in claim <NUM>, and a photovoltaic module as defined in claim <NUM>. Preferred features are defined in the dependent claims. The solar cell has an improved conversion efficiency and reduced manufacturing cost.

In one aspect, embodiments of the present disclosure provide a solar cell. The solar cell includes: a bottom cell including a front surface and a back surface opposite to each other, an inter layer located on the front surface of the bottom cell, a perovskite top cell located on the inter layer, and a back electrode located on the back surface of the bottom cell.

The perovskite top cell includes a hole transport layer, a perovskite layer, an electron transport layer, and a conductive structure stacked on a surface of the inter layer. The conductive structure includes at least one stack, each stack includes a first conductive layer and a second conductive layer stacked with the first conductive layer, and the second conductive layer is located between the first conductive layer and the electron transport layer. The first conductive layer includes a first transparent conductive film, and the second conductive layer includes a metal conductive film in a metallization region and a second transparent conductive film in a non-metallization region.

In another aspect, embodiments of the present disclosure provide a method for manufacturing a solar cell. The manufacturing method including the following steps:.

In yet another aspect, embodiments of the present disclosure provide a photovoltaic module. The photovoltaic module includes a plurality of solar cell strings, and each of the solar cell strings includes a plurality of solar cells electrically connected to one another. At least one solar cell each includes: a bottom cell including a front surface and a back surface opposite to each other, an inter layer located on the front surface of the bottom cell, a perovskite top cell located on the inter layer, and a back electrode located on the back surface of the bottom cell.

The perovskite top cell includes: a hole transport layer, a perovskite layer, an electron transport layer, and a conductive structure stacked on a surface of the inter layer. The conductive structure includes at least one stack, each stack includes a first conductive layer and a second conductive layer stacked with the first conductive layer, and the second conductive layer is located between the first conductive layer and the electron transport layer. The first conductive layer includes a first transparent conductive film, and the second conductive layer includes a metal conductive film in a metallization region and a second transparent conductive film in a non-metallization region.

According to the solar cell in the present disclosure, the metal conductive film corresponding to the metallization region in the conductive structure improves the conductivity of the conductive structure. Therefore, the solar cell can obtain higher conductivity without the front electrode, and charge collection efficiency of a tandem cell can be improved, thereby improving conversion efficiency. In addition, the second conductive layer is located between the first conductive layer and the electron transport layer, that is, the outermost layer of the solar cell is a first conductive layer, which can protect the metal conductive film and prevent the metal conductive film from being affected by the outside.

In order to more clearly illustrate the technical solutions in embodiments of the present disclosure, the accompanying drawings required to be used in the description of the embodiments or the related art will be briefly introduced below. It is apparent that, the accompanying drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those of ordinary skill in the art from the provided drawings without creative efforts.

In order to better understand the technical solutions of the present disclosure, embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

It is to be made clear that the described embodiments are only some rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts fall within the protection scope of the present disclosure.

The terms used in the embodiments of the present disclosure are intended only to describe particular embodiments and are not intended to limit the present disclosure. As used in the embodiments of the present disclosure and the appended claims, the singular forms of "a/an", "the", and "said" are intended to include plural forms, unless otherwise clearly specified by the context.

It is to be understood that the term "and/or" used herein is merely an association relationship describing associated objects, indicating that three relationships may exist. For example, A and/or B indicates that there are three cases of A alone, A and B together, and B alone. In addition, the character "/" herein generally means that associated objects before and after it are in an "or" relationship.

In most of conventional silicon-perovskite tandem solar cells, a transparent conductive layer is a thin film made of Indium Tin Oxide (ITO), Indium-Zinc-Oxide (IZO), Transparent Conductive Oxide (TCO), and the like, so conductivity of the transparent conductive layer is poor. In order to improve conductivity of the solar cell, there is a need to deposit a metal electrode on a surface of the transparent conductive layer to improve the conductivity. However, electrodes (generally made of gold, silver, and the like) are relatively expensive, which increases the cost of the solar cell.

Therefore, embodiments of the present disclosure provide a solar cell <NUM>. The solar cell <NUM> has high conductivity and a low cost.

<FIG> is a schematic structural diagram of a solar cell <NUM> according to the present disclosure. As shown in <FIG>, the solar cell <NUM> includes a bottom cell <NUM>, an inter layer <NUM>, a perovskite top cell <NUM>, and a back electrode <NUM>.

The bottom cell <NUM> includes a front surface and a back surface opposite to each other.

The inter layer <NUM> and the perovskite top cell <NUM> are located on the front surface of the bottom cell <NUM>. The perovskite top cell <NUM> includes a hole transport layer <NUM>, a perovskite layer <NUM>, an electron transport layer <NUM>, and a conductive structure <NUM> stacked on a surface of the inter layer <NUM>. The conductive structure <NUM> includes at least one stack, each stack includes a first conductive layer <NUM> and a second conductive layer <NUM> stacked with the first conductive layer <NUM>, and the second conductive layer <NUM> is located between the first conductive layer <NUM> and the electron transport layer <NUM>. The first conductive layer <NUM> includes a first transparent conductive film. The second conductive layer <NUM> includes a metal conductive film <NUM> in a metallization region and a second transparent conductive film <NUM> in a non-metallization region. As shown in <FIG>, the second conductive layer <NUM> includes a metallization region and a non-metallization region, the metal conductive film <NUM> is arranged in the metallization region, and the second transparent conductive film <NUM> is arranged in the non-metallization region. As shown in <FIG>, the metal conductive film <NUM> and the second transparent conductive film <NUM> are arranged in different regions of the second conductive layer <NUM>.

The back electrode <NUM> is located on the back surface of the bottom cell <NUM>.

In the solar cell provided by embodiments of in the present disclosure, the metal conductive film <NUM> corresponding to the metallization region in the conductive structure improves the conductivity of the conductive structure <NUM>, so that the solar cell <NUM> has a higher conductivity without being provided with the front electrode <NUM>, and charge collection efficiency of a tandem cell is improved, thereby improving conversion efficiency of the solar cell. In addition, the second conductive layer <NUM> is located between the first conductive layer <NUM> and the electron transport layer <NUM>, that is, the first conductive layer <NUM> is at the outermost layer of the solar cell, which can protect the metal conductive film <NUM> and prevent the metal conductive film <NUM> from being affected by the outside.

In the present disclosure, the metal conductive film <NUM> is arranged in the metallization region of the conductive structure. Compared with the arrangement that a metal layer is arranged on the entire surface, the metal conductive film <NUM> can improve the conductivity of the conductive structure without affecting absorption of sunlight by the solar cell, thereby improving photoelectric conversion efficiency of the solar cell.

In some embodiments of the present disclosure, the solar cell <NUM> does not include the front electrode <NUM>, the metallization region refers to a region in the second conductive layer <NUM> corresponding to the back electrode <NUM>, and the non-metallization region refers to a region in the second conductive layer <NUM> other than metallization region. For example, the metallization region overlaps the back electrode <NUM> in a plan view.

A type of the bottom cell <NUM> is not limited in the present disclosure. The bottom cell <NUM> is a silicon solar cell. For example, the bottom cell <NUM> may be a heterojunction cell (HIJ cell), a passivated emitter and rear contact (PERC) cell, a passivated emitter rear totally diffused (PERT) cell, a tunnel oxide passivated contact (TOPCon) cell, or the like.

For example, when the bottom cell <NUM> is the HIJ cell, the HIJ cell includes a crystalline silicon substrate, and the crystalline silicon substrate has a front surface and a back surface opposite to each other. The front surface of the crystalline silicon substrate is sequentially provided with an intrinsic hydrogenated amorphous silicon layer, a P-type hydrogenated amorphous silicon layer, and a front transparent conductive layer. The inter layer is located on a surface of the front transparent conductive layer. The back surface of the crystalline silicon substrate is provided with an intrinsic hydrogenated amorphous silicon layer, an n-type hydrogenated amorphous silicon layer, and a back transparent conductive layer. The back electrode <NUM> is located on the surface of the back transparent conductive layer. The front surface of the crystalline silicon substrate refers to a surface facing the sunlight, and a back surface of the semiconductor substrate refers to a surface facing away from the sunlight.

For example, when the bottom cell <NUM> is the PERT cell, the PERT cell includes a first passivation layer, a second passivation layer, an n-type silicon substrate, a p-type doped emitter, a tunneling layer, and a doped polysilicon layer arranged in sequence from bottom to top. The back electrode <NUM> may include finger lines and busbar lines, and the finger lines of the back electrode <NUM> are embedded in and penetrate through the first passivation layer and the second passivation layer, and are in contact with the n-type silicon substrate. The P-type doped emitter, the tunneling layer, and the doped polysilicon layer form a tunnel junction. The first passivation layer includes a silicon nitride layer, a silicon oxide layer, or a stacked structure of silicon nitride and silicon oxide. The second passivation layer includes a phosphorous diffusion layer. The tunneling layer includes at least one of a silicon oxide layer, an aluminum oxide layer, and a silicon carbide layer. The doped polysilicon layer may be formed by doping a polycrystalline and then performing a high-temperature treatment on the polycrystalline.

For example, when the bottom cell is the TOPCon cell, the TOPCon cell includes a passivation layer, an n-type silicon substrate, a tunneling layer, and a doped polysilicon layer arranged in sequence from bottom to top. The back electrode <NUM> is embedded in the passivation layer, penetrates through the passivation layer, and is in contact with the n-type silicon substrate. The doped polysilicon layer is in contact with the inter layer. The passivation layer includes a silicon nitride layer, a silicon oxide layer, or a stacked structure formed by silicon nitride and silicon oxide. The tunneling layer includes at least one of a silicon oxide layer, an aluminum oxide layer, and a silicon carbide layer. The doped polysilicon layer may be formed by doping a polycrystalline and then performing a high-temperature treatment on the polycrystalline. The tunneling layer and the doped polysilicon layer jointly form a passivated contact structure.

In the present disclosure, the inter layer <NUM> includes a tunnel junction or a transparent conductive layer. Photo-induced electrons generated by the perovskite top cell <NUM> and photo-induced holes generated by the bottom cell <NUM> are recombined in the tunnel junction. For example, the transparent conductive layer may be made of TCOs, indium-doped zinc oxide (IZO), ITO, transparent electrode Ag, or the like. The inter layer <NUM> has a good light transmitting property and a good conductivity. The inter layer <NUM> connects the bottom cell <NUM> and the perovskite top cell <NUM> to achieve ohmic contact, thereby ensuring recombination of the electrons and the holes inside the cell and improving bandgap matching between the bottom cell <NUM> and the top cell.

In some embodiments, not all of them forming part of the claimed invention, a material of the metal conductive film <NUM> includes at least one of Ni, Cu, Al, Ni, Sn, Zn, Ag, and Au. The conductivity of the metal conductive film <NUM> made of the above material is greater than that of the transparent conductive film (generally made of ITO, IZO, or TCO), and lateral transport of electrons in the conductive structure <NUM> can be improved, so that the conductivity of the conductive structure <NUM> is improved. In this way, the series resistance of the solar cell is reduced, charge transport capability is improved, the short-circuit current density of the solar cell <NUM> is increased, and a fill factor is increased, thereby effectively improving photoelectric conversion efficiency of the solar cell <NUM>. In the claimed invention, the material of the metal conductive film <NUM> includes at least one of Ni, Cu, Al, Sn, and Zn. The above materials are unstable in nature, but have lower costs. Since a surface of the metal conductive film <NUM> is covered by the first transparent conductive film, the Ni, Cu, Al, Sn, and Zn that are unstable in nature can still exhibit a higher conductivity.

In some embodiments, the conductive structure <NUM> includes at least one stack, and each stack includes the first conductive layer <NUM> and the second conductive layer <NUM> stacked together. That is, the first conductive layer <NUM> and the second conductive layer <NUM> constitute a multi-layer structure, and the conductive structure <NUM> may include one multi-layer structure, two stacked multi-layer structures, three stacked multi-layer structures, four stacked multi-layer structures, or the like. A number of multi-layer structures (each including the first conductive layer <NUM> and the second conductive layer <NUM>) in the conductive structure <NUM> is not limited in embodiments of the present disclosure, which may be designed according to a conductivity requirement of the solar cell <NUM>. <FIG> shows a solar cell <NUM> including a conductive structure <NUM> including one multi-layer structure, one layer of the multi-layer structure is a first transparent conductive layer, and the other layer of the multi-layer structure is the second conductive layer <NUM>. The first transparent conductive layer is the outermost layer of the solar cell <NUM>. <FIG> shows a solar cell <NUM> including a conductive structure <NUM> including two multi-layer structures. The conductive structure <NUM> includes two first conductive layers <NUM> and two second conductive layers <NUM>. When the conductive structure <NUM> of the solar cell <NUM> includes two or more stacks each constituted by the first conductive layer <NUM> and the second conductive layer <NUM>, the metal conductive films <NUM> in different stacks may be made of a same material or different materials. In some embodiments, the metal conductive films <NUM> in different stacks are made of different materials, instability of the metal conductive film <NUM> away from the electron transport layer <NUM> is less than that of the metal conductive film <NUM> close to the electron transport layer <NUM>, thereby improving electrical properties of the solar cell. For example, a metal conductive film <NUM> adjacent to the electron transport layer <NUM> is a Cu layer, and another conductive film <NUM> away from the electron transport layer <NUM> is an Al layer.

In some embodiments, a thickness of the metal conductive film <NUM> ranges from <NUM> to <NUM>. For example, the thickness of the metal conductive film <NUM> is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. In some embodiments, the thickness of the metal conductive film <NUM> is a thickness of the second conductive layer <NUM>.

In some embodiments, a thickness of the conductive structure <NUM> ranges from <NUM> to <NUM>. For example, the thickness of the conductive structure <NUM> may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. The thickness of the conductive structure <NUM> of the present disclosure is substantially equal to the thickness of the transparent conductive layer of the conventional silicon-perovskite tandem cell. That is, the conductivity of the solar cell can be improved without changing the thickness of the conductive layer. In some embodiments, the thickness of the conductive structure <NUM> ranges from <NUM> to <NUM>.

In some embodiments, the conductive structure <NUM> further includes a third conductive layer <NUM>, the third conductive layer <NUM> is located between the second conductive layer <NUM> and the electron transport layer <NUM>, and the third conductive layer <NUM> includes a third transparent conductive film. That is, in the conductive structure <NUM> of the solar cell <NUM> in the present disclosure, two surfaces of the second conductive layer <NUM> are each provided with a transparent conductive layer.

In some embodiments, the thickness of the second conductive layer <NUM> is greater than that of the first conductive layer <NUM>, and the second conductive layer <NUM> includes the metal conductive film <NUM>. In the present disclosure, the thickness of the second conductive layer <NUM> is greater than that of the first conductive layer <NUM>, the conductivity of the conductive structure <NUM> can be further improved, and efficiency of carrier collection can be improved.

In some embodiments, the solar cell <NUM> further includes a front electrode <NUM> located on the front surface of the conductive structure. The front surface of the conductive structure <NUM> is a surface of the outermost first conductive layer <NUM> in the conductive structure <NUM>. Through the cooperation of the metal conductive film <NUM> in the metallization region and the front electrode <NUM>, the conductivity of the solar cell <NUM> can be further improved.

It may be understood that, when the solar cell <NUM> includes the front electrode <NUM>, the metal conductive film <NUM> may correspond to a position of the front electrode <NUM> or correspond to a position of the back electrode <NUM>. In some embodiments, to enable the solar cell <NUM> to absorb more sunlight, the metal conductive film <NUM> may correspond to the position of the front electrode <NUM>.

In some embodiments, a material of the front electrode <NUM> includes at least one of Ag and Au.

In some embodiments, a material of the back electrode <NUM> includes at least one of Ag and Au.

In some embodiments, when the solar cell <NUM> of the present disclosure includes the front electrode <NUM>, the amount of the material used for forming the front electrode <NUM> may be reduced due to the presence of the conductive structure <NUM>. As shown in <FIG>, the front electrode <NUM> includes finger lines <NUM> extending in parallel, a gap G between adjacent finger lines of the finger lines of the front electrode <NUM> may be increased (expanded), so as to ensure the conductivity of the solar cell and reduce manufacturing costs.

In some embodiments, the finger lines <NUM> each extend in a longitudinal direction, and the gap G of the finger lines <NUM> of the front electrode <NUM> ranges from <NUM> to <NUM>. For example, the gap G of the finger lines <NUM> of the front electrode <NUM> is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. In some embodiments, the finger lines <NUM> each extend in a transverse direction, and the gap G of the finger lines <NUM> of the front electrode <NUM> ranges from <NUM> to <NUM>. For example, the gap G of the finger lines <NUM> of the front electrode <NUM> is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. Whereas, the gap G of adjacent finger lines of a conventional silicon-perovskite cell generally ranges from <NUM> to <NUM>. The gap G of the finger lines <NUM> of the front electrode <NUM> in the present disclosure is greater than that of a conventional tandem solar cell respectively, which can reduce the number of lines of the front electrode and save the cost without affecting the conductivity of the solar cell.

In some embodiments, the front electrode <NUM> includes first finger lines <NUM> and second finger lines (not shown in <FIG>). The first finger lines <NUM> extend in parallel along a first direction, and the second finger lines extend in parallel along a second direction crossing the first direction. For example, the second direction is perpendicular to the first direction. The gap between adjacent first finger lines <NUM> ranges from <NUM> to <NUM>. The gap between adjacent second finger lines is greater than the gap between adjacent first finger lines <NUM>.

In some embodiments, a ratio of a height of the front electrode <NUM> to a height of the back electrode <NUM> is greater than or equal to <NUM>. For example, the ratio of the height of the front electrode <NUM> to the height of the back electrode <NUM> may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. It may be understood that the height of the back electrode <NUM> in the present disclosure is the same as heights of the back electrode <NUM> and the front electrode <NUM> in the conventional silicon-perovskite tandem cell. In the present disclosure, the material amount used for forming the front electrode <NUM> may be reduced by arranging the conductive structure <NUM>. For example, the height of the front electrode <NUM> may be reduced, so as to ensure the conductivity of the solar cell and reduce manufacturing costs. In some embodiments, the ratio of the height of the front electrode <NUM> to the height of the back electrode <NUM> ranges from <NUM> to <NUM>.

The present disclosure further provides a method for manufacturing the above solar cell <NUM>.

A bottom cell <NUM> is provided. The bottom cell <NUM> includes a front surface and a back surface opposite to each other.

An inter layer <NUM> and a perovskite top cell <NUM> are formed on the front surface of the bottom cell <NUM>. The perovskite top cell <NUM> includes a hole transport layer <NUM>, a perovskite layer <NUM>, an electron transport layer <NUM>, and a conductive structure <NUM> stacked on a surface of the composite layer <NUM>. The conductive structure <NUM> includes at least one stack. Each stack includes a first conductive layer <NUM> and a second conductive layer <NUM> stacked together, and the second conductive layer <NUM> is located between the first conductive layer <NUM> and the electron transport layer <NUM>. The first conductive layer <NUM> includes a first transparent conductive film, and the second conductive layer <NUM> includes a metal conductive film <NUM> corresponding to a metallization region and a second transparent conductive film <NUM> corresponding to a non-metallization region.

A back electrode <NUM> is formed on the back surface of the bottom cell <NUM>.

According to embodiments of the present disclosure, the conductive structure <NUM> is formed on a surface of the electron transport layer <NUM>, and the conductive structure <NUM> includes the first conductive layer <NUM> and the second conductive layer <NUM> stacked together. The second conductive layer <NUM> includes the metal conductive film <NUM> corresponding to the metallization region and the second transparent conductive film <NUM> corresponding to the non-metallization region. Due to the existence of the metal conductive film <NUM>, conductivity of the conductive structure <NUM> can be improved, so that the solar cell <NUM> can obtain a higher conductivity without being provided with the front electrode <NUM>, thereby improving charge collection efficiency of the tandem cell and finally improving conversion efficiency of the tandem cell. In addition, in the present disclosure, the second conductive layer <NUM> is located between the first conductive layer <NUM> and the electron transport layer <NUM>. The outermost layer of the tandem solar cell is a first conductive layer <NUM>. In this way, the metal conductive film <NUM> is protected, and the metal conductive film <NUM> is prevented from being affected by the outside.

In the present disclosure, the metal conductive film <NUM> is arranged in the metallization region of the conductive structure. Compared with a metal layer arranged on the entire surface, the present disclosure can improve the conductivity of the conductive structure without affecting absorption of sunlight by the solar cell, thereby improving photoelectric conversion efficiency of the solar cell.

It may be understood that the solar cell <NUM> of the present disclosure is a tandem cell composed of a silicon cell and a perovskite solar cell <NUM>. The scope of protection is defined by the appended set of claims.

The manufacturing method of the present disclosure is described below according to specific embodiments. The manufacturing method includes steps shown in <FIG>. Intermediate structures formed in various steps of the manufacturing method are shown in <FIG>.

In step S100, a bottom cell <NUM> is provided. The bottom cell <NUM> includes a front surface and a back surface opposite to each other. A structure of the bottom cell <NUM> is as shown in <FIG>.

A type and a manufacturing method of the bottom cell <NUM> are not limited in the present disclosure. For example, the bottom cell <NUM> may be a HIJ cell, a p-type cell (PERC cell), a TOPCon cell, or the like.

In step S200, an inter layer <NUM> is formed on the front surface of the bottom cell <NUM>, and a structure shown in <FIG> is obtained.

In this step, the inter layer <NUM> includes a tunnel junction or a transparent conductive layer. Photo-induced electrons generated by the perovskite top cell <NUM> and photo-induced holes generated by the bottom cell <NUM> are recombined in the tunnel junction. For example, the transparent conductive layer may be made of TCOs, IZO, ITO, transparent electrode Ag, or the like. The inter layer <NUM> has a good light transmitting property and a good conductivity. The inter layer <NUM> connects the bottom cell <NUM> and the perovskite top cell <NUM> to achieve ohmic contact, thereby ensuring recombination of the electrons and the holes inside the cell and improving bandgap matching between the bottom cell <NUM> and the top cell.

In step S300, a perovskite top cell <NUM> is formed on a surface of the inter layer2.

In some embodiments, the perovskite top cell <NUM> is formed according to the method shown in <FIG>. As shown in <FIG>, in step S301, a hole transport layer <NUM>, a perovskite layer <NUM>, and an electron transport layer <NUM> are formed in sequence on the surface of the inter layer <NUM>, and a structure shown in <FIG> is obtained.

In some embodiments, the hole transport layer <NUM> refers to a layer that extracts and transports photo-induced holes generated in the perovskite layer <NUM>, including, but not limited to, an organic material and an inorganic material. For example, the organic material includes at least one of <NUM>,<NUM>',<NUM>,<NUM>'-tetra[N,N-bis(<NUM>-methoxyphenyl)amino]-<NUM>,<NUM>'-spirobifluorene (spiro-OMeTAD), poly[bis(<NUM>-phenyl)(<NUM>,<NUM>,<NUM>-trimethylphenyl)amine] (PTAA), and poly3-hexylthiophene (P3HT). The inorganic material includes at least one of Cul, CuSCN, TiO<NUM>, and SnO<NUM>.

In some embodiments, a thickness of the hole transport layer <NUM> ranges from <NUM> to <NUM>. The thickness of the hole transport layer <NUM> may be, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. If the thickness of the hole transport layer <NUM> is within the above range, it is conducive to improving an open-circuit voltage and a fill factor.

In some embodiments, the hole transport layer <NUM> is formed by at least one of magnetron sputtering, high-temperature spraying, and spin coating.

The perovskite cell refers to the solar cell including the perovskite layer <NUM>, and perovskite in the perovskite layer <NUM> refers to a crystal material with a structure of ABX<NUM> and similar structures.

A is a monovalent cation, including, but not limited to, at least one of Rb+, Na+, K+, Cs+, HN=CHNH<NUM>+ (abbreviated as FA), and CH<NUM>NH<NUM>+ (abbreviated as MA).

B is a divalent cation, including, but not limited to, at least one of Sn<NUM>+ and Pb<NUM>+.

X is selected from at least one of a halogen anion (F-, Cl-, Br, or the like), O<NUM>-, and S<NUM>-.

In the structure, B is located at a center of a cubic cell body, X is located at a center of a cube surface, and A is located at a vertex of a cube. The structure of the perovskite solar cell is more stable than a structure connected in a colloid or coplanar form, which is conducive to diffusion and migration of defects.

The perovskite layer <NUM> includes, but is not limited to, at least one of, for example, CH<NUM>NH<NUM>Pbl<NUM>, (CS)x(FA)<NUM>-xPbl<NUM>, (FA)x(MA)<NUM>-xPbl<NUM>, (FA)x(MA)<NUM>-x PblyCl<NUM>-y, and (FAPbl<NUM>)x(MAP-bBr<NUM>)<NUM>-x, where x ranges <NUM> to <NUM> and y ranges <NUM> to <NUM>.

When exposed to sunlight, the perovskite layer <NUM> first absorbs photons and generates electron-hole pairs. The carriers either become free carriers or form excitons according to a difference in binding energy of perovskite excitons. Moreover, the perovskite material generally has a lower carrier recombination probability and a higher carrier mobility, so the carriers have a longer diffusion distance and a longer lifetime. For example, a carrier diffusion length of CH<NUM>NH<NUM>Pbl<NUM> is at least <NUM>. A diffusion length of CH<NUM>NH<NUM>Pbl<NUM>-xClx is even greater than <NUM>, where x ranges <NUM> to <NUM>. The solar cell <NUM> including the perovskite layer <NUM> can obtain relatively excellent performance. In some embodiments, the perovskite layer is made of CH<NUM>NH<NUM>Pbl<NUM>.

In some embodiments, a thickness of the perovskite layer <NUM> ranges from <NUM> to <NUM>. The thickness of the perovskite layer <NUM> may be, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. If the thickness of the perovskite layer <NUM> is within the above range, it is conducive to absorption of light and inhibiting recombinations of carriers.

In some embodiments, the perovskite layer <NUM> is formed by at least one of spin coating, spraying, blade coating, and evaporation.

The perovskite layer <NUM> according to the present disclosure is inexpensive and can be manufactured using a solution, making it easier to manufacture than conventional silicon solar cells by using a roll-to-roll technology that does not require vacuum conditions.

The electron transport layer <NUM> (ETM) refers to a layer that extracts and transports photo-induced electrons generated in the perovskite layer <NUM>, including, but not limited to, an inorganic material or a polymer material. For example, the inorganic material includes at least one of ZnO and MoO<NUM>. The polymer material includes at least one of a fullerene derivative (PCBM) and C60.

In some embodiments, a thickness of the electron transport layer <NUM> ranges from <NUM> to <NUM>. The thickness of the electron transport layer <NUM> may be, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. If the thickness of the electron transport layer <NUM> is controlled within the above range, it is conducive to electron transport.

In some embodiments, the electron transport layer <NUM> is formed by at least one of spraying, blade coating, evaporation, and spin coating.

It may be understood that the hole transport layer <NUM>, the perovskite layer <NUM>, and the electron transport layer <NUM> may be manufactured by a same method or by different methods.

In step S302, a conductive structure is formed on a surface of the electron transport layer <NUM>.

In some embodiments, step S302 includes step S3021 and step S3022. In step S3021, a second conductive layer <NUM> is formed on the surface of the electron transport layer <NUM>. As shown in <FIG>, the second conductive layer <NUM> includes a metal conductive film <NUM> corresponding to a metallization region and a second transparent conductive film corresponding to a non-metallization region.

In some embodiments, before the second conductive layer <NUM> is formed on the surface of the electron transport layer <NUM>, a third conductive layer <NUM> is formed on the surface of the electron transport layer <NUM> first, and then the second conductive layer <NUM> is formed on a surface of the third conductive layer <NUM>, and a structure shown in <FIG> is obtained.

In some embodiments, the third conductive layer <NUM> includes a transparent conductive film, and the transparent conductive film includes at least one of an ITO film, an IZO film, and a TCO film.

In some embodiments, the third conductive layer <NUM> is manufactured by a physical vapor deposition process. For example, the physical vapor deposition process includes at least one of magnetron sputtering, thermal evaporation, and electron beam physical deposition.

In some embodiments, the metal conductive film <NUM> corresponding to the metallization region and the second transparent conductive film <NUM> corresponding to the non-metallization region may be formed using a screen printing process combined with a sintering process. In some other embodiments, a physical vapor deposition process may be adopted. For example, the physical vapor deposition process includes at least one of magnetron sputtering, thermal evaporation, and electron beam physical deposition.

In some embodiments, not all of them forming part of the claimed invention, the metal conductive film <NUM> is formed using at least one of an Ni source, a Cu source, an Al source, an Sn source, a Zn source, an Ag source, and an Au source. The conductivity of the metal conductive film <NUM> made of the above material is greater than that of the transparent conductive film (generally made of ITO, IZO, or TCO), and the price is low, so that the conductivity of the conductive structure <NUM> is improved and the cost is reduced, thereby reducing series resistance of the solar cell and improving charge transport capability, which can not only increase short-circuit current density of the solar cell <NUM>, but also increase a fill factor, thereby effectively improving photoelectric conversion efficiency of the solar cell <NUM>.

In some embodiments, the metal conductive film <NUM> corresponding to the metallization region and the second transparent conductive film corresponding to the non-metallization region may be formed using an etching process. That is, firstly, a transparent conductive film is formed on the surface of the electron transport layer <NUM>, then the transparent conductive film is removed by etching in the metallization region of the transparent conductive film, and then the metal conductive film <NUM> is formed by a deposition process or a screen printing process.

In some embodiments, the second transparent conductive film <NUM> includes at least one of an ITO film, an IZO film, and a TCO film.

In step S3022, a first conductive layer <NUM> is formed on a surface of the second conductive layer <NUM>, to obtain a structure as shown in <FIG>.

In some embodiments, the first conductive layer <NUM> is formed by at least one of a sputtering process and a deposition process.

In some embodiments, the first conductive layer <NUM> (i.e., the first transparent conductive film) includes at least one of an ITO film, an IZO film, and a TCO film. It may be understood that materials of the first transparent conductive film and the second transparent conductive film <NUM> may be the same or different.

In some embodiments, when the number of the stack including first conductive layer <NUM> and the second conductive layer <NUM> is greater than or equal to <NUM>, step S3021 and step S3022 are repeated.

In some embodiments, the solar cell <NUM> of the present disclosure further includes: step S500 of forming a front electrode <NUM> on a surface of the conductive structure, and a structure shown in <FIG> is obtained. The front surface of the conductive structure <NUM> may be a surface of the outermost first conductive layer <NUM> in the conductive structure <NUM>.

In some embodiments, the front electrode <NUM> is manufactured by at least one of vacuum evaporation, electron beam deposition, electroplating, and screen printing.

In some embodiments, a gap of the finger lines of the front electrode <NUM> ranges from <NUM> to <NUM>. For example, the gap of the finger lines of the front electrode <NUM> is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and a gap of the finger lines of a conventional silicon-perovskite cell generally ranges from <NUM> to <NUM>. The gap of the finger lines of the front electrode <NUM> in the present disclosure is greater than that of a conventional tandem solar cell, which can save the amount of the material for forming the front electrode and save the cost without affecting the conductivity of the solar cell.

In some embodiments, a ratio of a height of the front electrode <NUM> to a height of the back electrode <NUM> is greater than or equal to <NUM>%. For example, the ratio of the height of the front electrode <NUM> to the height of the back electrode <NUM> may be <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>%. If the height of the front electrode <NUM> is within the above range, it indicates that an amount of the material for forming the front electrode <NUM> of the present disclosure is reduced, thereby ensuring the conductivity of the solar cell and reducing manufacturing costs. In some embodiments, the ratio of the height of the front electrode <NUM> to the height of the back electrode <NUM> ranges from <NUM>% to <NUM>%.

In step S400, a back electrode <NUM> is formed on the back surface of the bottom cell <NUM>, and the solar cell <NUM> is obtained.

It may be understood that the front electrode <NUM> may be optionally formed in the present disclosure. That is, a solar cell <NUM>, as shown in <FIG>, not including the front electrode <NUM> but only including the back electrode <NUM> may be manufactured in the present disclosure. In some other embodiments, a solar cell, as shown in <FIG>, including both the front electrode <NUM> and the back electrode <NUM> may be manufactured in the present disclosure.

In some embodiments, the back electrode <NUM> is formed by at least one of vacuum evaporation, electron beam deposition, electroplating, and screen printing.

In some embodiments, a gap of the finger lines of the back electrode <NUM> ranges from <NUM> to <NUM>. For example, the gap of the finger lines of the back electrode <NUM> may be <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

In some embodiments, a height of the back electrode ranges from <NUM> to <NUM>. For example, the height of the back electrode may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

Embodiments of the present disclosure provide a photovoltaic module <NUM>. The photovoltaic module <NUM> includes a solar cell string. The solar cell string includes a plurality of solar cells electrically connected to each other. The solar cell is the tandem solar cell including a silicon bottom cell and a perovskite top cell as descried in any above embodiment.

For example, referring to <FIG>, the photovoltaic module <NUM> includes a first cover plate <NUM>, a first encapsulation adhesive layer <NUM>, a solar cell string, a second encapsulation adhesive layer <NUM>, and a second cover plate <NUM>.

In some embodiments, the solar cell string includes a plurality of solar cells <NUM> as described above that are connected by conductive leads. The solar cells <NUM> may be connected by partial stack or by splicing.

In some embodiments, the first cover plate <NUM> and the second cover plate <NUM> may be transparent or opaque cover plates, such as glass cover plates or plastic cover plates.

Two sides of the first encapsulation adhesive layer <NUM> are in contact with and attached to the first cover plate <NUM> and the solar cell string respectively, and two sides of the second encapsulation adhesive layer <NUM> are in contact with and attached to the second cover plate <NUM> and the solar cell string respectively. The first encapsulation adhesive layer <NUM> and the second encapsulation adhesive layer <NUM> each may be an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene co-elastomer (POE) adhesive film or a polyethylene terephthalate (PET) adhesive film.

Side edges of the photovoltaic module <NUM> may also be completely encapsulated. That is, the side edges of the photovoltaic module <NUM> are fully encapsulated with an encapsulation adhesive tape to prevent position deviation during the lamination of the photovoltaic module <NUM>.

The photovoltaic module <NUM> further includes an edge sealing member. The edge sealing member is fixedly packaged to a partial edge of the photovoltaic module <NUM>. The edge sealing member may be fixedly packaged to an edge near a corner of the photovoltaic module <NUM>. The edge sealing member may be a high-temperature resistant tape. The high-temperature resistant tape has excellent high-temperature resistance and may not decompose or fall off during the lamination, which can ensure the reliable packaging of the photovoltaic module <NUM>. Two ends of the high-temperature resistant tape are fixed to the second cover plate <NUM> and the first cover plate <NUM> respectively. The two ends of the high-temperature resistant tape may be bonded to the second cover plate <NUM> and the first cover plate <NUM> respectively, and the middle thereof can limit a side edge of the photovoltaic module <NUM> to prevent a lamination deviation of the photovoltaic module <NUM> during the lamination.

Claim 1:
A solar cell comprising:
a bottom cell (<NUM>), comprising a front surface and a back surface opposite to each other;
a perovskite top cell (<NUM>);
an inter layer (<NUM>) between the front surface of the bottom cell (<NUM>) and the perovskite top cell (<NUM>); and
a back electrode (<NUM>) located on the back surface of the bottom cell (<NUM>),
wherein the perovskite top cell (<NUM>) comprises a hole transport layer (<NUM>), a perovskite layer (<NUM>), an electron transport layer (<NUM>), and a conductive structure (<NUM>) stacked on the inter layer,
wherein the conductive structure (<NUM>) comprises at least one stack, each stack comprises a first conductive layer (<NUM>) and a second conductive layer (<NUM>), the second conductive layer (<NUM>) is located between the first conductive layer (<NUM>) and the electron transport layer (<NUM>), the first conductive layer (<NUM>) comprises a first transparent conductive film, and the second conductive layer (<NUM>) comprises a metal conductive film (<NUM>) in a metallization region of the second conductive layer and a second transparent conductive film (<NUM>) in a non-metallization region of the second conductive layer,
wherein a material of the metal conductive film (<NUM>) comprises at least one of Ni, Cu, Al, Sn, and Zn.