Perovskite tandem photovoltaic cell module and method of manufacturing the same

Abstract

The application provides a perovskite laminated photovoltaic cell module and a preparation method thereof. The module comprises a plurality of first cell groups connected in parallel, each first cell group comprises a plurality of laminated cell pieces connected in series, and each laminated cell piece comprises a perovskite cell and a crystalline silicon cell stacked together. The first light-absorbing layer and the first hole transport layer of the perovskite cell are subjected to P2 laser scribing to form a plurality of perovskite sub-cells connected in parallel, and the perovskite cell is used for absorbing short-wavelength light in front sunlight. The second hole transport layer and the intermediate electrode layer of the crystalline silicon cell are subjected to P1 laser scribing to form a plurality of crystalline silicon sub-cells connected in parallel, the perovskite cell is used for absorbing long-wavelength light in front sunlight, and the absolute value of the difference between the current densities of the perovskite cell and the crystalline silicon cell is less than or equal to a first preset value. In the application, the current density consistency of the perovskite cell and the crystalline silicon cell in the laminated cell piece is high, which is conducive to reducing electrical loss and improving power generation efficiency.

Description

Technical Field

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

[0002] The efficiency of single-crystal silicon solar cells is gradually approaching the theoretical limit of 29.4%, limiting the potential for further reductions in the cost per kilowatt-hour. Combining the chemical, physical, and mechanical properties of semiconductor materials with different band gaps can overcome the limitations of the properties and efficiency of a single component. Consequently, tandem cells have rapidly developed as a new technological approach. Perovskite / crystalline silicon tandems are currently a very important industrialization direction in the photovoltaic solar cell field and are currently the preferred solution for achieving breakthrough structural upgrades in crystalline silicon solar cells.

[0003] Striving to obtain a more matched cell structure is key to ensuring good performance of tandem solar cells. Currently, the most commonly used tandem technology is perovskite and crystalline silicon tandems. The transparent conductive oxide (TCO) film on the surface acts as a natural intermediate tunneling layer, effectively enabling the upper and lower series connection of the cells. This unique advantage makes it the optimal bottom cell choice in the perovskite / crystalline silicon tandem route. The original design intention of perovskite / crystalline silicon tandem solar cells is to stack perovskite materials to improve the efficiency of solar cells in the ultraviolet band. Through the rational distribution of the absorption spectrum of each layer structure, the PCE of the solar cell can theoretically be increased to over 40%, which is expected to further reduce the photovoltaic cost per kilowatt-hour over a longer period of time. However, in existing perovskite tandem cell solutions, the current density gap between the top cell and the bottom cell is large, resulting in excessive current loss and heating of the cell components. Meeting the current matching between the sub-cells is the primary challenge in manufacturing 2T tandem solar cells. Summary of the Invention

[0004] The present application provides a perovskite stacked photovoltaic cell assembly and a preparation method thereof. The top perovskite cell is suitable for wide bandgap materials, the bandgap width is controlled at 1.65-2.5eV, and it absorbs short-wavelength light; the bottom crystalline silicon cell is suitable for narrow bandgap materials, which absorbs long-wavelength light. At the same time, the thickness of the top cell is adjusted to control the light intensity and wavelength reaching the top and bottom cells respectively, thereby making the current density tend to be consistent, and after P1 and P2 engraving, the current consistency can be ensured to reduce loss.

[0005] In a first aspect, the present application provides a perovskite tandem photovoltaic cell assembly, comprising a plurality of first cell groups connected in parallel, wherein a single first cell group comprises a plurality of tandem cell sheets connected in series, wherein a single tandem cell sheet comprises a stacked perovskite cell and a crystalline silicon cell, wherein the perovskite cell is located on top of the tandem cell sheet, and the crystalline silicon cell is located at the bottom of the tandem cell sheet; wherein,

[0006] The perovskite cell comprises a first top electrode, a first electron transport layer, a first light absorption layer, a first hole transport layer and a first bottom electrode arranged in sequence, the first electron transport layer, the first light absorption layer and the first hole transport layer are formed by P2 laser scribing to form a plurality of parallel connected perovskite sub-cells, and the perovskite cell is used to absorb short-wavelength light in the front-side sunlight.

[0007] The crystalline silicon cell comprises a second top electrode, a second hole transport layer, a second light absorption layer, a second electron transport layer and a second bottom electrode arranged in sequence, the second hole transport layer and the intermediate electrode layer are formed by P1 laser scribing to form a plurality of parallel connected crystalline silicon sub-cells, the intermediate electrode layer comprises the first bottom electrode and the second top electrode, the plurality of perovskite sub-cells and the plurality of crystalline silicon sub-cells are in one-to-one series connection, the perovskite cell is used to absorb long-wavelength light in the front-side sunlight, and the absolute value of the current density difference between the perovskite cell and the crystalline silicon cell is less than or equal to a first preset value.

[0008] In some embodiments, the band gap width of the perovskite cell is 1.65-2.5eV, and is used to absorb sunlight with a wavelength of 760nm or less in the front-side sunlight; and the crystalline silicon cell is used to absorb sunlight with a wavelength of 760-1033nm in the front-side sunlight.

[0009] In some embodiments, the first thickness of the first light absorption layer is 150-450nm, the second thickness of the perovskite cell is 750-1150nm, and the first thickness and the second thickness are used to determine the light absorption rate of the perovskite cell for sunlight with a wavelength of 760nm or less in the front-side sunlight; wherein the light absorption rate includes a first light absorption rate for sunlight in a first wavelength band and a second light absorption rate for sunlight in a second wavelength band, the first light absorption rate is greater than the second light absorption rate, the first wavelength band is 320-460nm, and the second wavelength band is 460-760nm.

[0010] In some embodiments, any two adjacent crystalline silicon sub-cells in the plurality of crystalline silicon sub-cells are spaced apart by a first channel, the distance between any two adjacent first channels is a first preset distance, and the insulation resistance between any two first channels is greater than or equal to 20MΩ; any two adjacent perovskite sub-cells in the plurality of perovskite sub-cells are spaced apart by a second channel, and the distance between any one second channel and the adjacent first channel is a second preset distance.

[0011] In some embodiments, the first top electrode, the middle electrode layer and the second bottom electrode are transparent conductive oxides, the transparent conductive oxides at least include one of ITO, AZO, FTO and ZnO; the perovskite cell is a thin film cell, the first light-absorbing layer is a perovskite thin film, the first electron transport layer is an inorganic oxide or an organic semiconductor substance, and the first hole transport layer is an organic small molecule substance or a polymer substance; the crystalline silicon cell is a thin film cell, the second light-absorbing layer is a silicon wafer, the second hole transport layer includes P-type amorphous silicon and intrinsic hydrogenated amorphous silicon, and the second electron transport layer includes the intrinsic hydrogenated amorphous silicon and N-type amorphous silicon.

[0012] In some embodiments, the perovskite stacked photovoltaic cell assembly further includes a first encapsulation adhesive film and a first encapsulation substrate, a first end surface of the first encapsulation adhesive film is attached to a first end surface of the first top electrode, and a second end surface of the first encapsulation adhesive film is attached to a first end surface of the first encapsulation substrate; the perovskite stacked photovoltaic cell assembly further includes a second encapsulation adhesive film and a second encapsulation substrate, a first end surface of the second encapsulation adhesive film is attached to a first end surface of the second bottom electrode, and a second end surface of the second encapsulation adhesive film is attached to a first end surface of the second encapsulation substrate, the first encapsulation substrate and the second encapsulation substrate are glass substrates, and the first encapsulation substrate and the second encapsulation substrate have different thicknesses.

[0013] In a second aspect, the embodiments of the present application provide a preparation method of a perovskite stacked photovoltaic cell assembly, applied to the perovskite stacked photovoltaic cell assembly of the first aspect of the embodiments of the present application, and the method includes: performing electrical testing on a plurality of crystalline silicon cells to obtain a plurality of electrical parameters corresponding to the plurality of crystalline silicon cells one by one.

[0014] According to the plurality of electrical parameters and a first preset condition, a plurality of first combinations and a plurality of reference electrical parameters are determined, a single first combination includes a plurality of crystalline silicon cells, and the plurality of first combinations correspond to the plurality of reference electrical parameters one by one.

[0015] performing the following operations for each of the first combinations to obtain a plurality of stacked battery pieces: determining the first preset distance according to the reference electrical parameter corresponding to the first combination currently processed, and performing the P1 laser scribing on each of the crystalline silicon cells in the first combination according to the first preset distance; and determining the first thickness and the second thickness according to the reference electrical parameter, and configuring a plurality of perovskite cells according to the first thickness and the second thickness, the plurality of perovskite cells being the same in number as the plurality of crystalline silicon cells in the first combination; and performing the P2 laser scribing on the plurality of perovskite cells according to the second preset distance; and stacking the plurality of perovskite cells and the plurality of crystalline silicon cells one by one to obtain a plurality of stacked battery pieces corresponding to the first combination;

[0016] determining the plurality of first battery groups according to the plurality of stacked battery pieces and a second preset condition;

[0017] performing circuit connection and packaging on the plurality of first battery groups respectively to obtain the perovskite stacked photovoltaic battery module.

[0018] In some embodiments, the determining the plurality of first battery groups according to the plurality of stacked battery pieces and a second preset condition comprises: performing the electrical test on the plurality of stacked battery pieces to obtain a plurality of test results corresponding one by one to the plurality of stacked battery pieces; determining a plurality of reference battery groups according to the plurality of test results and the second preset condition, a single reference battery group including a plurality of stacked battery pieces for series connection; and determining the plurality of first battery groups according to a third preset condition and the plurality of reference battery groups, the plurality of first battery groups being a plurality of reference battery groups in the plurality of reference battery groups that satisfy the third preset condition.

[0019] In some embodiments, before the performing the P2 laser scribing on the plurality of perovskite cells according to the second preset distance, the method further comprises: determining a second reference distance or a second distance interval according to the reference electrical parameter corresponding to the first combination currently processed, the second distance interval including a plurality of values corresponding to the second preset distance; and determining the second preset distance according to the first thickness, the second thickness and the second reference distance, or determining the second preset distance according to the first thickness, the second thickness and the second distance interval.

[0020] It can be seen that in the embodiment of the present application, the perovskite laminated photovoltaic cell assembly includes a plurality of first cell groups in parallel, a single first cell group includes a plurality of laminated cell pieces in series, and a single laminated cell piece includes a stacked perovskite cell and a crystalline silicon cell, the perovskite cell is located at the top of the laminated cell piece, and the crystalline silicon cell is located at the bottom of the laminated cell piece; wherein the perovskite cell includes a first top electrode, a first electron transport layer, a first light absorption layer, a first hole transport layer and a first bottom electrode arranged in sequence, the first electron transport layer, the first light absorption layer and the first hole transport layer are formed into a plurality of perovskite sub-cells in parallel by P2 laser scribing, and the perovskite cell is used to absorb short-wavelength light in front-sunlight; the crystalline silicon cell includes a second top electrode, a second hole transport layer, a second light absorption layer, a second electron transport layer and a second bottom electrode arranged in sequence, the second hole transport layer and the intermediate electrode layer are formed into a plurality of crystalline silicon sub-cells in parallel by P1 laser scribing, the intermediate electrode layer includes the first bottom electrode and the second top electrode, the plurality of perovskite sub-cells and the plurality of crystalline silicon sub-cells have a one-to-one series connection relationship, the perovskite cell is used to absorb long-wavelength light in front-sunlight, and the absolute value of the difference between the current densities of the perovskite cell and the crystalline silicon cell is less than or equal to a first preset value. In this way, compared with the problem of low current density consistency and large electrical loss in the existing perovskite laminated cell scheme, the present application can control the wavelength, transmittance, irradiance and other parameters of the light transmitted through the top cell based on the regulation of the thickness and band gap of the top cell and laser scribing, thereby controlling the actual current density of the bottom cell, keeping the current densities of the top cell and the bottom cell consistent, and achieving the best series connection effect. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is a structure diagram of a perovskite laminated photovoltaic cell assembly provided by an embodiment of the present application;

[0023] Figure 2 is one of the structure schematic diagrams of a perovskite laminated photovoltaic cell assembly provided by an embodiment of the present application;

[0024] Figure 3 is the second of the structure schematic diagrams of a perovskite laminated photovoltaic cell assembly provided by an embodiment of the present application;

[0025] Figure 4 is a front irradiation light path schematic diagram provided by an embodiment of the present application;

[0026] Figure 5 is a schematic diagram of electron transport under front illumination provided by an embodiment of the present application;

[0027] Figure 6 is a schematic diagram of a stacked cell provided by an embodiment of the present application;

[0028] Figure 7 is a flowchart of a preparation method of a perovskite stacked photovoltaic cell module provided by an embodiment of the present application;

[0029] Figure 8 is a circuit schematic diagram of a perovskite stacked cell provided by an embodiment of the present application.

[0030] Legend of reference signs:

[0031] 1-stacked cell, 10-perovskite cell, 20-crystalline silicon cell, 30-intermediate electrode layer, 101-first top electrode, 102-first electron transport layer, 103-first light absorbing layer, 104-first hole transport layer, 105-first bottom electrode, 110-first encapsulation substrate, 120-first encapsulation adhesive film, 201-second top electrode, 202-second hole transport layer, 203-second light absorbing layer, 204-second electron transport layer, 205-second bottom electrode, 210-first encapsulation substrate, 220-first encapsulation adhesive film. DETAILED DESCRIPTION

[0032] In order to enable persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] The terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0034] Reference to“an embodiment” herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase“in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be incorporated in a combination of embodiments.

[0035] In embodiments of the present application, “and / or” describes an association relationship between associated objects, which means that there can be three relationships. For example, A and / or B can represent the following three cases: A exists alone; A and B exist simultaneously; and B exists alone. A and B can be singular or plural.

[0036] In embodiments of the present application, the symbol“ / ” can represent an“or” relationship between the associated objects before and after it. In addition, the symbol“ / ” can also represent the division sign, that is, performing division operation. For example, A / B can represent A divided by B.

[0037] In embodiments of the present application, “at least one” or similar expressions mean any combination of these items, including any combination of single item or multiple items, means one or more, and multiple means two or more. For example, at least one of a, b or c can represent the following seven cases: a, b, c, a and b, a and c, b and c, and a, b and c. Each of a, b and c can be an element or a set containing one or more elements.

[0038] In embodiments of the present application, “equal to” can be combined with greater than, which is applicable to the technical solutions adopted when greater than; or can be combined with less than, which is applicable to the technical solutions adopted when less than. When equal to is combined with greater than, it is not combined with less than; when equal to is combined with less than, it is not combined with greater than.

[0039] The tandem solar cell technology is generally composed of two main parts: a perovskite cell on top and a crystalline silicon cell on the bottom. The wider bandgap light-absorbing layer is on top of the cell, which collects most of the high-energy photons, while the bottom narrower bandgap material can absorb the remaining low-energy photons. The basic working principle of the tandem cell is to achieve efficient utilization of the solar spectrum by stacking layers of structures with different bandgaps (Eg) in the optical sequence, and when the photons are absorbed, the excited electrons and holes are transported to the two electrodes under the action of the built-in electric field, and finally a voltage is generated at the two ends of the cell.

[0040] According to the existing current collection mode, the laminated battery structure can be divided into two types of two ends (2T) and four ends (4T), and the heterojunction battery front surface TCO layer is directly used as a tunneling layer to realize effective series connection of crystalline silicon and perovskite battery. However, in order to form more uniform perovskite crystals, the front surface of the heterojunction bottom battery is generally polished or micro-textured, which will partially affect the light capture of the bottom battery. In addition, due to the series electrical coupling of the integrated configuration of the top battery and the bottom battery, the short-circuit current density (JSC) of the series device is limited by the lowest sub-cell JSC, and when the current density difference between the two sides of the battery is large, there will be a large current loss and a battery component heating problem. Therefore, strictly meeting the current matching between the sub-cells is the primary challenge of manufacturing 2T laminated solar cells. The 4T is composed of two completely independent sub-cells in the circuit structure, and the process is simple, but the 4T laminated structure needs additional transparent electrodes and glass layers, which consumes more in terms of packaging and manufacturing cost, and there is a voltage matching problem to be solved. At present, due to the problems of transmission and loss caused by electrical coupling and heterojunction interface, the preparation difficulty and process control requirement of large-area 2T laminated solar cell are higher.

[0041] In view of the above problems, the embodiments of the present application provide a perovskite laminated photovoltaic cell module and a preparation method thereof. The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0042] Please refer to Figure 1 , Figure 1 is a structure diagram of a perovskite laminated photovoltaic cell module provided by the embodiments of the present application. The perovskite laminated photovoltaic cell module includes a plurality of first battery groups connected in parallel, and each first battery group includes a plurality of laminated cell pieces connected in series. Each laminated cell piece 1 includes a perovskite cell 10 and a crystalline silicon cell 20 stacked together. The perovskite cell 10 is located at the top of the laminated cell piece 1, and the crystalline silicon cell 20 is located at the bottom of the laminated cell piece 1. The perovskite cell 10 is connected with a first encapsulation adhesive film 120, and the first encapsulation adhesive film 120 is connected with a first encapsulation substrate 110. The crystalline silicon cell 20 is connected with a second encapsulation adhesive film 220, and the second encapsulation adhesive film 220 is connected with a second encapsulation substrate 210.

[0043] Among them, see Figure 2 , the perovskite cell 10 includes a first top electrode 101, a first electron transport layer 102, a first light absorption layer 103, a first hole transport layer 104 and a first bottom electrode 105 arranged in sequence, and the perovskite cell 10 is used for absorbing short-wavelength light in the front sunlight. The crystalline silicon cell 20 includes a second top electrode 201, a second hole transport layer 202, a second light absorption layer 203, a second electron transport layer 204 and a second bottom electrode 205 arranged in sequence, and the intermediate electrode layer 30 includes the first bottom electrode 105 and the second top electrode 201. The perovskite cell 10 is used for absorbing long-wavelength light in the front sunlight.

[0044] In some embodiments, the first end surface of the first encapsulation adhesive film 120 is attached to the first end surface of the first top electrode 101, and the second end surface of the first encapsulation adhesive film 120 is attached to the first end surface of the first encapsulation substrate 110; the first end surface of the second encapsulation adhesive film 220 is attached to the first end surface of the second bottom electrode 205, and the second end surface of the second encapsulation adhesive film 220 is attached to the first end surface of the second encapsulation substrate 210; the first encapsulation substrate 110 and the second encapsulation substrate 210 are glass substrates, and the thicknesses of the first encapsulation substrate 110 and the second encapsulation substrate 210 are different.

[0045] In some embodiments, the first top electrode 101, the intermediate electrode layer 30, and the second bottom electrode 205 are transparent conductive oxides, and the transparent conductive oxides at least include one of ITO, AZO, FTO, and ZnO; the perovskite cell 10 is a thin-film cell, the first light-absorbing layer 103 is a perovskite thin film, the first electron transport layer 102 is an inorganic oxide or an organic semiconductor substance, and the first hole transport layer 104 is an organic small-molecule substance or a polymer substance; the crystalline silicon cell 20 is a thin-film cell, the second light-absorbing layer 203 is a silicon wafer, the second hole transport layer 202 includes P-type amorphous silicon and intrinsic hydrogenated amorphous silicon, and the second electron transport layer 204 includes the intrinsic hydrogenated amorphous silicon and N-type amorphous silicon.

[0046] Further, see Figure 3 , the first electron transport layer 102, the first light-absorbing layer 103, and the first hole transport layer 104 are formed into a plurality of parallel perovskite sub-cells through P2 laser scribing, the second hole transport layer 202 and the intermediate electrode layer 30 are formed into a plurality of parallel crystalline silicon sub-cells through P1 laser scribing, and the plurality of perovskite sub-cells and the plurality of crystalline silicon sub-cells are in one-to-one series connection.

[0047] In some embodiments, any two adjacent crystalline silicon sub-cells in the plurality of crystalline silicon sub-cells are separated by a first channel, the distance between any two adjacent first channels is a first preset distance, and the insulation resistance between any two first channels is greater than or equal to 20 MΩ.

[0048] Any two adjacent perovskite sub-cells in the plurality of perovskite sub-cells are separated by a second channel, and the distance between any one second channel and the adjacent first channel is a second preset distance.

[0049] In some embodiments, the band gap width of the perovskite cell is 1.65-2.5 eV, for absorbing sunlight with a wavelength of 760 nm or less in the front sunlight; and the crystalline silicon cell is for absorbing sunlight with a wavelength of 760-1033 nm in the front sunlight.

[0050] In some embodiments, a first thickness of the first light absorbing layer is 150-450 nm, and a second thickness of the perovskite cell is 750-1150 nm. The first thickness and the second thickness are used to determine the light absorptivity of the perovskite cell for solar light with a wavelength of less than 760 nm in the front sunlight; wherein the light absorptivity includes a first light absorptivity for solar light in a first wavelength band and a second light absorptivity for solar light in a second wavelength band, the first light absorptivity is greater than the second light absorptivity, the first wavelength band is 320-460 nm, and the second wavelength band is 460-760 nm.

[0051] It can be seen that in this embodiment, the top cell mainly uses a perovskite cell with a band gap width of 1.65-2.5eV, which mainly absorbs sunlight with a wavelength below 760nm. The thickness of the perovskite layer is 150-450nm, and the thickness of the entire top cell film is controlled at 750-1150nm. The comprehensive transmittance of the entire top cell to sunlight with a wavelength of 320-460nm is less than 20%, the comprehensive transmittance to sunlight with a wavelength of 460-760nm is less than 35%, and the comprehensive transmittance to sunlight with a wavelength above 760nm is greater than 40%. The bottom cell crystalline silicon cell material mainly absorbs sunlight with a wavelength below 750-1150nm, so that they can be optically matched, with the top cell mainly absorbing short waves in sunlight and the bottom cell mainly absorbing long waves in sunlight.

[0052] See also Figure 4 , Figure 4 This is a schematic diagram of a front illumination light path provided by an embodiment of the present application. When sunlight E0 is incident, there is reflected light E1 on the surface of the encapsulation glass, and the remaining sunlight E2 enters the interior of the laminated cell 1. Light E4 is absorbed by the top perovskite cell 10. Among them, the top cell mainly uses a band gap width of 1.65-2.5eV. Under standard conditions, the current density is about 23-27mA / The perovskite cell 10 mainly absorbs sunlight with a wavelength below 760nm. The thickness of the perovskite layer is 150-450nm, and the thickness of the entire top cell film is controlled at 750-1150nm. The comprehensive absorption rate of the entire top cell for sunlight with a wavelength of 320-460nm is about 80%, the comprehensive absorption rate for sunlight with a wavelength of 460-760nm is about 65%, and the comprehensive absorption rate for sunlight with a wavelength above 760nm is less than 60%.

[0053] Furthermore, the remaining light E3 passes through the top cell and enters the bottom cell. Under standard conditions, the current density is 35-45 mA / , the bottom cell can absorb the sunlight with the wavelength of 760-1033nm, so that the top cell and the bottom cell can be matched optically, the top cell mainly absorbs the short wave of the sunlight, the bottom cell mainly absorbs the sunlight with the wavelength of 760-1033nm, E6 and E7 represent the light reflected by the different cells. The lower end of the bottom cell is the positive electrode of the stacked cell sheet, which is represented by the symbol "+", and the upper end of the top cell is the negative electrode of the stacked cell sheet, which is represented by the symbol "-". From the structure, the top cell is equivalent to being irradiated under the standard irradiance, and the current density is large. Due to the existence of the top cell, the irradiance received by the bottom cell is low, and the current density of the cell is not fully excited. The overall current density is about 21-24mA .

[0054] It can be understood that under the solar irradiance, when the solar cell is irradiated by the sunlight, the light absorption layer material of the cell absorbs the photons, the energy of the photons excites the electrons originally bound around the atomic nucleus from the top of the valence band to the bottom of the conduction band, so as to form free electrons (e-) and holes (h+), that is, carriers. The carrier concentration is the number of carriers in a unit volume, and the current density is the current passing through the cross section perpendicular to the current direction per unit time. During the conduction process, the current density is proportional to the carrier concentration, because the current passing through a certain cross section per unit time is determined by the number of carriers in a unit volume. The greater the carrier concentration, the greater the current density; the smaller the carrier concentration, the smaller the current density. The light intensity directly affects the size of the photo-generated current, and the stronger the light, the greater the current.

[0055] Please refer to Figure 5 , Figure 5 is an electronic transport schematic diagram under front irradiation provided by the embodiment of the application. When P1 scribing is performed, the width a of P1 scribing is controlled, and the width of P1 and P2 is b, and the error is kept within ±10um.

[0056] Under natural light irradiation, the top perovskite cell 10 and the bottom crystalline silicon cell 20 will generate free moving electrons Because the second top electrode 201 (TCO) and second hole transport layer 202 (including P-type amorphous silicon and intrinsic hydrogenated amorphous silicon layers) of the bottom cell were horizontally disconnected during P1 scribing, electrons can only be transmitted in the Z-axis direction. When the electrons from the bottom cell reach the intermediate electrode layer 30, they merge with the electrons generated by the top cell and continue to transmit within the top cell, forming a current loop. After being collected by the second bottom electrode 205 of the bottom cell, they return to the bottom cell. Therefore, the lower end of the bottom cell is the positive electrode of the stacked cell, represented by the symbol "+", and the upper end of the top cell is the negative electrode of the stacked cell, represented by the symbol "-". At this time, the width of the electron transmission along the Z-axis of the bottom cell is a, and the width of the electron transmission along the Z-axis of the top cell is also a. The number of perovskite sub-cells and crystalline silicon sub-cells in series is one-to-one.

[0057] It is understandable that when performing P1 scribing, it is necessary to ensure that the P1 laser can completely scribe the intermediate electrode layer 30 and the second hole transport layer 202 (including P-type amorphous silicon and intrinsic hydrogenated amorphous silicon layer), and ensure that the insulation resistance between the channels is ≥20MΩ. This ensures that during subsequent electron transmission, electrons can only be transmitted in the Z-axis direction, and the intermediate electrode layer 30 is not affected when performing P2 scribing. After the scribing is completed, in order to improve the charge collection ability of the laminated cell 1, one of a metal wire, a carbon paste, and a silver paste is prepared on the first top electrode 101 and the second bottom electrode 205. The excellent conductive properties of the metal wire, carbon paste, and silver paste are used to collect the charge generated by the laminated cell 1. Then, multiple laminated cells 1 are connected together in series or in parallel through bus bars. Finally, the multiple laminated cells 1 are encapsulated together by two layers of encapsulation film to form a perovskite laminated photovoltaic cell module.

[0058] See also Figure 6 , Figure 6 1 is a schematic diagram of a laminated battery cell provided in an embodiment of the present application, and the schematic diagram of the laminated battery cell is a front view of the laminated battery cell.

[0059] Exemplarily, the width of the stacked cell is W and the length is L. After P1 and P2 laser scribing, there are M sub-cell groups connected in parallel vertically and N sub-cells connected in series horizontally. The length of the cell after scribing is d=L / M, the width of each crystalline silicon sub-cell in the bottom crystalline silicon cell is a=W / N, and the width of each perovskite sub-cell in the top perovskite cell is a=W / N. The lengths of each sub-cell in the top perovskite cell and the bottom crystalline silicon cell are the same, both d=L / M. Then the area of ​​the bottom crystalline silicon sub-cell sbottom=a×d=WL / NM, and the area of ​​the top crystalline silicon sub-cell stop=a×d=WL / NM.

[0060] Further, in combination with the formula for the photocurrent density, it is known that the current density is related to the thickness of the light-absorbing layer of the material and the intensity of the incident light. By controlling the thickness, band gap, and film layer data of the top cell, the irradiance and wavelength of the light transmitted through the top cell can be controlled, thereby controlling the actual current density of the bottom cell, so that the current of the bottom cell is equal to or slightly less than that of the top cell. In this way, the top cell and the bottom cell can have substantially consistent current under series connection, achieving maximum current output.

[0061] Please refer to Figure 7 , Figure 7 is a flowchart of a preparation method of a perovskite stacked photovoltaic cell module provided by an embodiment of the present application. The method comprises:

[0062] S701, performing electrical testing on a plurality of crystalline silicon cells to obtain a plurality of electrical parameters corresponding to the plurality of crystalline silicon cells.

[0063] The electrical parameters can include voltage, current, and fill factor. Specifically, the fill factor and other parameters can be obtained by applying a certain voltage or current to the bottom cell using professional battery testing equipment, and measuring the output voltage, current, and other data. For example, the fill factor can be calculated by the formula FF=Pmax / (Voc×Isc), where Pmax is the maximum power, Voc is the open circuit voltage, and Isc is the short circuit current.

[0064] S702, determining a plurality of first combinations and a plurality of reference electrical parameters according to the plurality of electrical parameters and a first preset condition, wherein a single first combination includes a plurality of crystalline silicon cells, and the plurality of first combinations correspond to the plurality of reference electrical parameters one by one.

[0065] For example, the first preset condition can be that the current difference is within 0.1 mA, and then the reference electrical parameters corresponding to combination A can be: current about 10.0 mA, voltage 0.6 V, and fill factor 0.75; the reference electrical parameters corresponding to combination B can be: current about 10.1 mA, voltage 0.61 V, and fill factor 0.76; and the reference electrical parameters corresponding to combination C can be: current about 10.2 mA, voltage 0.62 V, and fill factor 0.77.

[0066] S703, for each of the first combination, the following operation is performed to obtain a plurality of stacked battery pieces: determining the first preset distance according to the reference electrical parameter corresponding to the first combination currently processed, and performing the P1 laser scribing on each crystalline silicon cell in the first combination respectively according to the first preset distance; and determining the first thickness and the second thickness according to the reference electrical parameter, and configuring a plurality of perovskite cells according to the first thickness and the second thickness, the number of the plurality of perovskite cells being the same as that of the plurality of crystalline silicon cells in the first combination; and performing the P2 laser scribing on the plurality of perovskite cells respectively according to the second preset distance; and stacking the plurality of perovskite cells and the plurality of crystalline silicon cells one by one to obtain a plurality of stacked battery pieces corresponding to the first combination.

[0067] The width of the P1-P2 laser scribing is mainly 100-200um.

[0068] In some embodiments, before the P2 laser scribing is performed on the plurality of perovskite cells respectively according to the second preset distance, the method further comprises:

[0069] determining a second reference distance or a second distance interval according to the reference electrical parameter corresponding to the first combination currently processed, the second distance interval including values corresponding to a plurality of the second preset distances;

[0070] determining the second preset distance according to the first thickness, the second thickness and the second reference distance, or determining the second preset distance according to the first thickness, the second thickness and the second distance interval.

[0071] It can be understood that the width of the P2 laser scribing is not only determined according to the reference electrical parameter, but also related to the thickness of the perovskite cell. The determination of the P1 scribing width will affect the position of the P2 scribing, thereby indirectly affecting the P1-P2 width after the P2 scribing. The change of the perovskite cell film thickness will affect the optical parameters such as light transmittance and absorption, and these optical parameters are closely related to the electrical performance of the battery. For example, the change of the perovskite light absorption layer thickness will affect the generation and transport of photo-generated carriers, and further affect the electrical characteristics such as the electric field distribution and current density inside the battery. In order to adapt to the performance influence caused by the change of the film thickness, the width of the P2 scribing also needs to be adjusted accordingly to ensure the overall performance of the battery is optimal.

[0072] For example, for the top cell corresponding to combination A, since the current of the bottom cell is small, in order to achieve current matching, the thickness of the perovskite absorption layer is adjusted to 300nm, and the thicknesses of the first electron transport layer and the first hole transport layer are also adjusted accordingly, and then P2 scratching is performed, and the P1-P2 width is maintained at 150um; for the top cell corresponding to combination B, the thickness of the perovskite absorption layer is adjusted to 320nm, and the thicknesses of the first electron transport layer and the first hole transport layer change accordingly, and the P1-P2 width after P2 scratching is 160um; for the top cell corresponding to combination C, the thickness of the perovskite absorption layer is adjusted to 340nm, and the thicknesses of the first electron transport layer and the first hole transport layer are adjusted accordingly, and the P1-P2 width after P2 scratching is 170um.

[0073] S704 , determining the plurality of first battery groups according to the plurality of stacked battery cells and a second preset condition.

[0074] In some embodiments, determining the plurality of first battery groups according to the plurality of stacked battery sheets and a second preset condition includes:

[0075] Performing the electrical test on the plurality of stacked battery cells to obtain a plurality of test results corresponding to the plurality of stacked battery cells;

[0076] Determine a plurality of reference battery packs according to the plurality of test results and the second preset condition, wherein a single reference battery pack includes a plurality of stacked battery cells connected in series;

[0077] The plurality of first battery groups are determined according to a third preset condition and the plurality of reference battery groups, and the plurality of first battery groups are a plurality of reference battery groups that meet the third preset condition among the plurality of reference battery groups.

[0078] It can be seen that after the production of the laminated solar cells is completed, the performance of the laminated solar cells will be retested and then classified to ensure the series and parallel connection of the subsequent laminated solar cells. Among them, in the selection of series and parallel connection methods, under the premise of ensuring maximum power output, series and parallel connection are selected according to different classifications. For example, if the second preset condition is set to a current difference of less than 0.1mA, this type of product will be used in series connection; if the third preset condition is set to a voltage difference of less than 0.2mV, this type of product will be used in parallel connection. After completing the series and parallel circuit connections of the laminated solar cells, the components are packaged, and the production process of the photovoltaic cell component is completed.

[0079] S705 , respectively performing circuit connection and packaging on the plurality of first battery groups to obtain the perovskite laminated photovoltaic cell assembly.

[0080] It can be seen that, in the embodiment, after the bottom layer battery is tested for electrical performance, classification is performed, and in the preparation of the top layer battery film layer, the electrical performance parameters are fully relied on to control the wavelength, transmittance, irradiance and other parameters of the light transmitted through the top layer battery, so as to control the actual current density of the bottom layer battery, so that the current densities of the top layer battery and the bottom layer battery are consistent (the currents are also consistent), thereby realizing the best series effect. In addition, in the embodiment, the redundant laser process is reduced, and the problem that the performance of the assembly is reduced due to the micro-short circuit of the film layer in the Z axis caused by excessive use of laser scribing can be avoided.

[0081] Please refer to Figure 8 , Figure 8 is a circuit schematic diagram of a perovskite stacked battery piece provided by the embodiment of the present application, the perovskite stacked battery piece is divided into a plurality of regions, and the plurality of regions are connected in parallel.

[0082] It can be understood that dividing the perovskite stacked battery piece into a plurality of parallel regions can ensure that when the unit region of the perovskite stacked battery piece is unstable, the power generation efficiency of the entire stacked battery piece will not be affected.

[0083] Among them, the perovskite stacked battery piece is divided into M regions.

[0084] Among them, in the I region, , respectively represent the voltage and internal resistance of the crystalline silicon sub-cell, v1 and r1 respectively represent the voltage and internal resistance of the perovskite sub-cell, and in the M region, , respectively represent the voltage and internal resistance of the crystalline silicon sub-cell, vm and rm respectively represent the voltage and internal resistance of the perovskite sub-cell. Among them, in the I region, the current of the perovskite sub-cell and the crystalline silicon sub-cell is consistent, which is i1, the voltage of each group of series-connected perovskite sub-cells and crystalline silicon sub-cells is consistent, that is, the external output voltage is +v1, the output current is i1, therefore, in the I region, the external output voltage is +v1, and the output current is N x i1.

[0085] Further, in the I region to the M region, the output voltage of each region is +v1, and the output current of the entire perovskite stacked battery piece can be approximately equal to M x N x i1, so the output power P of the perovskite stacked battery piece is uout x iout=( +v1) x M x N x i1, wherein uout represents the output voltage of the perovskite stacked battery piece, and iout represents the output current of the perovskite stacked battery piece.

[0086] It can be seen that in the embodiment, the maximum power generation efficiency is achieved by stacking the perovskite wide band gap material and the crystalline silicon material. The band gap of the perovskite material can be regulated by adjusting the material composition and the film thickness, thereby the absorption wavelength and intensity of the light by the light absorption layer of the perovskite battery can be controlled, and the light intensity and wavelength transmitted through the perovskite battery can be controlled, and the light intensity and wavelength reaching the crystalline silicon battery can be controlled. In this way, the density of the photo-generated carriers and the current density of the crystalline silicon battery can be adjusted, so that the current density of the top perovskite battery and the current density of the bottom crystalline silicon battery are consistent. In addition, the middle electrode layer and the second hole transport layer are cut off by the P1 and P2 laser scribing, so that the carrier transport is along the Z-axis direction, and the current consistency of the top and bottom batteries is ensured, thereby the problem of excessive loss of electrons in the interface transmission caused by the electrical coupling of the perovskite battery and the crystalline silicon battery in the two-terminal (2T) perovskite stack scheme can be solved, and the power generation efficiency of the perovskite stack photovoltaic battery assembly can be improved.

[0087] In the present application, the phrase "embodiment" or "embodiments" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments. In addition, it should be understood that the features, structures or characteristics described in the embodiments of the present application can be combined with each other without contradiction, to form another embodiment of the present application without departing from the spirit and scope of the present application.

[0088] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application.

Claims

1. A perovskite tandem photovoltaic cell assembly, characterized in that: The invention comprises a plurality of first battery groups connected in parallel, wherein a single first battery group comprises a plurality of laminated battery sheets connected in series, wherein a single laminated battery sheet comprises a stacked perovskite battery and a crystalline silicon battery, wherein the perovskite battery is located on the top of the laminated battery sheet, and the crystalline silicon battery is located on the bottom of the laminated battery sheet; wherein, The perovskite cell includes a first top electrode, a first electron transport layer, a first light absorbing layer, a first hole transport layer and a first bottom electrode arranged in sequence. The first electron transport layer, the first light absorbing layer and the first hole transport layer are scribed by a P2 laser to form a plurality of perovskite sub-cells connected in parallel. The perovskite cell is used to absorb short-wavelength light in front sunlight. The first thickness of the first light absorbing layer is 150-450 nm, and the second thickness of the perovskite cell is 750-1150 nm. The crystalline silicon cell includes a second top electrode, a second hole transport layer, a second light absorption layer, a second electron transport layer and a second bottom electrode arranged in sequence. The second hole transport layer and the intermediate electrode layer are formed into a plurality of crystalline silicon sub-cells in parallel by P1 laser scribing. The intermediate electrode layer includes the first bottom electrode and the second top electrode. The plurality of perovskite sub-cells and the plurality of crystalline silicon sub-cells are in a one-to-one series relationship. The perovskite cell is used to absorb long-wavelength light in front sunlight. The absolute value of the difference between the current density of the perovskite cell and the crystalline silicon cell is less than or equal to a first preset value, wherein, A first channel is provided between any two adjacent crystalline silicon sub-cells among the multiple crystalline silicon sub-cells, and the distance between any two adjacent first channels is a first preset distance; a second channel is provided between any two adjacent perovskite sub-cells among the multiple perovskite sub-cells, and the distance between any second channel and the adjacent first channel is a second preset distance.

2. The perovskite tandem photovoltaic cell assembly according to claim 1, characterized in that: The perovskite cell has a band gap width of 1.65-2.5 eV and is used to absorb sunlight with a wavelength of less than 760 nm in the front sunlight; and The crystalline silicon cell is used to absorb sunlight with a wavelength between 760 nm and 1033 nm in the front sunlight.

3. The perovskite tandem photovoltaic cell assembly according to claim 2, characterized in that: The first thickness and the second thickness are used to determine the light absorption rate of the perovskite cell for the sunlight with a wavelength of less than 760nm in the front sunlight; wherein, The light absorption rate includes a first light absorption rate for sunlight in a first wavelength band and a second light absorption rate for sunlight in a second wavelength band, the first light absorption rate is greater than the second light absorption rate, the first wavelength band is 320-460nm, and the second wavelength band is 460-760nm.

4. The perovskite tandem photovoltaic cell assembly according to claim 3, characterized in that: The insulation resistance between any two of the first channels is greater than or equal to 20 MΩ.

5. The perovskite tandem photovoltaic cell assembly according to any one of claims 1 to 4, characterized in that: The first top electrode, the middle electrode layer and the second bottom electrode are transparent conductive oxides, and the transparent conductive oxide includes at least one of ITO, AZO, FTO and ZnO; The perovskite battery is a thin film battery, the first light absorption layer is a perovskite thin film, the first electron transport layer is an inorganic oxide or an organic semiconductor material, and the first hole transport layer is an organic small molecule material or a polymer material; The crystalline silicon cell is a thin film cell, the second light absorption layer is a silicon wafer, the second hole transport layer includes P-type amorphous silicon and intrinsic hydrogenated amorphous silicon, and the second electron transport layer includes the intrinsic hydrogenated amorphous silicon and N-type amorphous silicon.

6. The perovskite tandem photovoltaic cell assembly according to claim 5, characterized in that: The perovskite laminated photovoltaic cell assembly further includes a first encapsulation film and a first encapsulation substrate, wherein the first end surface of the first encapsulation film is bonded to the first end surface of the first top electrode, and the second end surface of the first encapsulation film is bonded to the first end surface of the first encapsulation substrate; The perovskite stacked photovoltaic cell assembly also includes a second packaging film and a second packaging substrate, the first end face of the second packaging film is bonded to the first end face of the second bottom electrode, the second end face of the second packaging film is bonded to the first end face of the second packaging substrate, the first packaging substrate and the second packaging substrate are glass substrates, and the thickness of the first packaging substrate and the second packaging substrate are different.

7. A method for preparing a perovskite tandem photovoltaic cell assembly, applied to the perovskite tandem photovoltaic cell assembly according to any one of claims 1 to 6, characterized in that: The method comprises: Performing electrical testing on a plurality of crystalline silicon cells to obtain a plurality of electrical parameters corresponding to the plurality of crystalline silicon cells; Determine a plurality of first combinations and a plurality of reference electrical parameters according to the plurality of electrical parameters and a first preset condition, wherein a single first combination includes a plurality of crystalline silicon cells, and the plurality of first combinations correspond one-to-one to the plurality of reference electrical parameters; For each of the first combinations, the following operations are performed to obtain a plurality of stacked cell sheets: determining the first preset distance according to the reference electrical parameters corresponding to the first combination currently being processed, and performing the P1 laser scribing on each crystalline silicon cell in the first combination according to the first preset distance; determining the first thickness and the second thickness according to the reference electrical parameters, and configuring a plurality of perovskite cells according to the first thickness and the second thickness, wherein the number of the plurality of perovskite cells is the same as the number of the plurality of crystalline silicon cells in the first combination; performing the P2 laser scribing on the plurality of perovskite cells according to the second preset distance; and stacking the plurality of perovskite cells and the plurality of crystalline silicon cells one-to-one to obtain a plurality of stacked cell sheets corresponding to the first combination; Determining the plurality of first battery groups according to the plurality of stacked battery sheets and a second preset condition; The plurality of first battery groups are respectively subjected to circuit connection and packaging to obtain the perovskite laminated photovoltaic cell assembly.

8. The method according to claim 7, characterized in that The determining of the plurality of first battery groups according to the plurality of stacked battery sheets and a second preset condition comprises: Performing the electrical test on the plurality of stacked battery cells to obtain a plurality of test results corresponding to the plurality of stacked battery cells; Determine a plurality of reference battery packs according to the plurality of test results and the second preset condition, wherein a single reference battery pack includes a plurality of stacked battery cells connected in series; The plurality of first battery groups are determined according to a third preset condition and the plurality of reference battery groups, and the plurality of first battery groups are a plurality of reference battery groups that meet the third preset condition among the plurality of reference battery groups.

9. The method according to claim 8, characterized in that Before performing the P2 laser scribing on the plurality of perovskite cells according to the second preset distance, the method further includes: determining a second reference distance or a second distance interval according to the reference electrical parameter corresponding to the currently processed first combination, where the second distance interval includes a plurality of values ​​corresponding to the second preset distance; The second preset distance is determined according to the first thickness, the second thickness, and the second reference distance, or the second preset distance is determined according to the first thickness, the second thickness, and the second distance interval.

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