Perovskite laminated photovoltaic cell module and preparation method thereof

Abstract

The invention provides a perovskite laminated photovoltaic cell assembly and a preparation method thereof, the perovskite laminated photovoltaic cell assembly comprises a plurality of first battery packs connected in parallel, each first battery pack comprises a plurality of laminated cells connected in series, and each laminated cell comprises a perovskite cell and a crystalline silicon cell which are stacked; a first light absorption layer and a first hole transport layer of the perovskite cell are etched by P2 laser to form a plurality of perovskite sub-cells which are 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 etched by P1 laser to form a plurality of crystalline silicon sub-cells which are 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 density of the perovskite cell and the current density of the crystalline silicon cell is smaller than or equal to a first preset value. According to the laminated battery piece, the current density consistency of the perovskite battery and the crystalline silicon battery in the laminated battery piece is high, the electrical loss can be reduced, and the power generation efficiency can be improved.

Description

Technical Field

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

[0002] The efficiency of single-crystal silicon solar cells has gradually approached the theoretical limit of 29.4%, limiting the potential for further reduction in the cost per kilowatt-hour. Combining the chemical, physical and mechanical properties of semiconductor materials with different band gaps can break through the limitations of single component properties and efficiency. Therefore, stacked cells have developed rapidly as a new technical route. Perovskite / crystalline silicon stacking is currently a very important industrialization direction in the field of photovoltaic solar cells, and is also the preferred solution for achieving structural breakthrough upgrades of crystalline silicon solar cells at this stage.

[0003] Trying to obtain a more matched cell structure is the key to ensure that the tandem solar cells have good performance. Perovskite and crystalline silicon tandem is currently the most commonly used tandem technology. The transparent conductive oxide (TCO) film on the surface acts as a natural intermediate tunneling layer, effectively realizing the upper and lower series connection of the cell. This unique advantage makes it the optimal bottom cell choice in the perovskite / crystalline silicon tandem route. The original intention of the design of perovskite / crystalline silicon tandem solar cells is to stack perovskite materials to improve the utilization rate of solar cells in the ultraviolet band. Through the reasonable distribution of the absorption spectrum of each layer structure, the PCE of the solar cell can be theoretically increased to more than 40%, which is expected to further reduce the photovoltaic cost per kilowatt-hour over a longer period of time. However, in the existing perovskite tandem cell solution, the current density difference between the top cell and the bottom cell is large, resulting in excessive current loss and heating of the battery 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. A top perovskite cell is suitable for a wide bandgap material, the bandgap width is controlled at 1.65-2.5eV, and short-wavelength light is absorbed; a bottom crystalline silicon cell is suitable for a narrow bandgap material, the bandgap width is controlled at 1.2-1.7eV, and long-wavelength light is absorbed. 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 the current consistency can be ensured after P1 and P2 marking to reduce loss.

[0005] In a first aspect, the present application provides a perovskite laminated photovoltaic cell assembly, comprising a plurality of first battery groups connected in parallel, wherein a single first battery group comprises a plurality of laminated cell sheets connected in series, wherein a single laminated cell sheet comprises a stacked perovskite cell and a crystalline silicon cell, wherein the perovskite cell is located at the top of the laminated cell sheet, and the crystalline silicon cell is located at the bottom of the laminated 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 into a plurality of perovskite sub-cells connected in parallel by P2 laser scribing, and the perovskite cell is used to absorb short-wavelength light in front sunlight;

[0007] 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 which are 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 through P1 laser engraving. 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 in current density 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 1.65-2.5 eV, which is used to absorb the solar light with a wavelength below 760 nm in the front sunlight; and the band gap width of the crystalline silicon cell is 1.2-1.7 eV, which is used to absorb the solar light with a wavelength between 760-1033 nm in the front sunlight.

[0009] In some embodiments, a first thickness of the first light absorbing layer is 150-450nm, and a 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 the solar light with a wavelength below 760nm in the front sunlight; wherein the light absorption rate includes a first light absorption rate for the solar light in the first band and a second light absorption rate for the solar light in the second band, the first light absorption rate is greater than the second light absorption rate, the first band is 320-460nm, and the second band is 460-760nm.

[0010] In some embodiments, a first channel is provided between any two adjacent crystalline silicon sub-cells among the multiple crystalline silicon sub-cells, a distance between any two adjacent first channels is a first preset distance, and an insulation resistance between any two first channels is greater than or equal to 20 MΩ; a second channel is provided between any two adjacent perovskite sub-cells among the multiple perovskite sub-cells, and a distance between any second channel and an 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, and the transparent conductive oxide includes at least one of ITO, AZO, FTO, and ZnO; the perovskite cell is a thin film cell, 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.

[0012] In some embodiments, the perovskite stacked photovoltaic cell assembly further includes a first packaging film and a first packaging substrate, wherein the first end face of the first packaging film is bonded to the first end face of the first top electrode, and the second end face of the first packaging film is bonded to the first end face of the first packaging substrate; the perovskite stacked photovoltaic cell assembly further includes a second packaging film and a second packaging substrate, wherein the first end face of the second packaging film is bonded to the first end face of the second bottom electrode, and the second end face of the second packaging film is bonded to the first end face of the second packaging substrate, and the first packaging substrate and the second packaging substrate are glass substrates, and the thicknesses of the first packaging substrate and the second packaging substrate are different.

[0013] In some embodiments, the current density of the perovskite cell and the crystalline silicon cell are calculated by the following formulas: i=J×S(1); J=e×α×h×β(2); wherein i is the current density, J is the photocurrent density, S is the cell area, e is the electron charge, α is the absorption coefficient of the material, h is the thickness of the light-absorbing layer, and β is the incident light irradiance.

[0014] In a second aspect, the present application embodiment provides a method for preparing a perovskite laminated photovoltaic cell assembly, which is applied to the perovskite laminated photovoltaic cell assembly as described in the first aspect of the present application embodiment, the method comprising: 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;

[0015] Determine a plurality of first combinations and a plurality of reference electrical parameters according to the plurality of electrical parameters and the 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;

[0016] Perform the following operations for each of the first combinations to obtain a plurality of stacked cell sheets: determine the first preset distance according to the reference electrical parameters corresponding to the first combination currently being processed, and perform the P1 laser scribing on each crystalline silicon cell in the first combination according to the first preset distance; and determine the first thickness and the second thickness according to the reference electrical parameters, and configure 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; and perform the P2 laser scribing on the plurality of perovskite cells according to the second preset distance; and stack the plurality of perovskite cells one-to-one with the plurality of crystalline silicon cells to obtain a plurality of stacked cell sheets corresponding to the first combination;

[0017] Determine the plurality of first battery groups according to the plurality of stacked battery sheets and a second preset condition;

[0018] The plurality of first battery groups are respectively circuit-connected and packaged to obtain the perovskite laminated photovoltaic cell assembly.

[0019] In some embodiments, determining the multiple first battery groups based on the multiple stacked battery cells and the second preset condition includes: performing the electrical test on the multiple stacked battery cells to obtain multiple test results corresponding to the multiple stacked battery cells; determining multiple reference battery groups based on the multiple test results and the second preset condition, a single reference battery group including multiple stacked battery cells for series connection; determining the multiple first battery groups based on a third preset condition and the multiple reference battery groups, the multiple first battery groups being multiple reference battery groups among the multiple reference battery groups that meet the third preset condition.

[0020] In some embodiments, before performing the P2 laser scribing on the multiple perovskite cells respectively according to the second preset distance, the method also includes: determining a second reference distance or a second distance interval according to the reference electrical parameters corresponding to the first combination currently being processed, the second distance interval including multiple values ​​corresponding to the second preset distance; 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.

[0021] It can be seen that in the embodiment of the present application, the perovskite laminated photovoltaic cell assembly includes a plurality of first battery groups connected in parallel, and a single first battery group includes a plurality of laminated battery sheets connected in series, wherein a single laminated battery sheet includes a stacked perovskite cell and a crystalline silicon cell, the perovskite cell is located at the top of the laminated battery sheet, and the crystalline silicon cell is located at the bottom of the laminated battery sheet; 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, and the first electron transport layer, the first light absorption layer and the first hole transport layer are formed into a plurality of perovskite cells connected in parallel by P2 laser engraving. The battery, the perovskite battery is used to absorb short-wavelength light in the front sunlight; the crystalline silicon battery 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-batteries in parallel through P1 laser scribing, the intermediate electrode layer includes a first bottom electrode and a second top electrode, the plurality of perovskite sub-batteries and the plurality of crystalline silicon sub-batteries are in a one-to-one series relationship, the perovskite battery is used to absorb long-wavelength light in the front sunlight, and the absolute value of the difference between the current density of the perovskite battery and the crystalline silicon battery is less than or equal to a first preset value. In this way, relative to the problems of low current density consistency and excessive electrical loss faced in the existing perovskite stacked battery solution, the present application can control the wavelength, transmittance, irradiance and other parameters of the light passing through the top battery based on the regulation of the thickness and band gap of the top battery, and laser scribing, thereby controlling the actual current density of the bottom battery, so that the current density of the top battery and the bottom battery remain consistent, thereby achieving the best series effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a simplified structural diagram of a perovskite tandem photovoltaic cell assembly provided in an embodiment of the present application;

[0024] Figure 2 This is one of the structural schematic diagrams of a perovskite laminated photovoltaic cell assembly provided in an embodiment of the present application;

[0025] Figure 3 This is the second structural schematic diagram of a perovskite laminated photovoltaic cell assembly provided in an embodiment of the present application;

[0026] Figure 4 This is a schematic diagram of a front illumination light path provided in an embodiment of the present application;

[0027] Figure 5 This is a schematic diagram of electron transmission under frontal illumination provided in an embodiment of the present application;

[0028] Figure 6 is a schematic diagram of a laminated battery cell provided in an embodiment of the present application;

[0029] Figure 7 It is a flow chart of a method for preparing a perovskite laminated photovoltaic cell assembly provided in an embodiment of the present application;

[0030] Figure 8 It is a circuit diagram of a perovskite stacked cell provided in an embodiment of the present application.

[0031] Description of reference numerals:

[0032] 1-stacked cell, 10-perovskite cell, 20-crystalline silicon cell, 30-middle electrode layer, 101-first top electrode, 102-first electron transport layer, 103-first light absorption layer, 104-first hole transport layer, 105-first bottom electrode, 110-first packaging substrate, 120-first packaging film, 201-second top electrode, 202-second hole transport layer, 203-second light absorption layer, 204-second electron transport layer, 205-second bottom electrode, 210-first packaging substrate, 220-first packaging film. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. 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 optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] In the embodiments of the present application, "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists alone; A and B exist at the same time; B exists alone. Among them, A and B can be singular or plural.

[0037] In the embodiment of the present application, the symbol " / " can indicate that the objects associated with each other are in an "or" relationship. In addition, the symbol " / " can also indicate a division sign, that is, performing a division operation. For example, A / B can indicate A divided by B.

[0038] In the embodiments of the present application, "at least one item" or similar expressions refer to any combination of these items, including any combination of single items or plural items, and refer to one or more, and multiple refers to two or more. For example, at least one item of a, b, or c can represent the following seven situations: a, b, c, a and b, a and c, b and c, a, b, and c. Among them, each of a, b, and c can be an element or a set containing one or more elements.

[0039] In the embodiments of the present application, "equal to" can be used in conjunction with greater than, and is applicable to the technical solution adopted when greater than, and can also be used in conjunction with less than, and is applicable to the technical solution adopted when less than. When equal to is used in conjunction with greater than, it is not used in conjunction with less than; when equal to is used in conjunction with less than, it is not used in conjunction with greater than.

[0040] Tandem solar cell technology usually consists of two main parts: a perovskite cell on the top and a crystalline silicon cell on the bottom. The wider bandgap light-absorbing layer is located on the top of the cell, collecting most of the high-energy photons, while the narrower bandgap material at the bottom can absorb the remaining low-energy photons. The basic working principle of the tandem cell is to achieve efficient use of the solar spectrum by stacking structural layers with different bandgaps (Eg) in an optical sequence. When photons are absorbed, the excited electrons and holes are transmitted to the two electrodes respectively under the action of the built-in electric field, and finally a voltage is generated at both ends of the cell.

[0041] According to the existing current collection method, the stacked cell structure can be divided into two types: two-terminal (2T) and four-terminal (4T). The TCO layer on the front surface of the heterojunction cell is used as a tunneling layer to directly realize the effective series connection of crystalline silicon and perovskite cells. However, in order to form more uniform perovskite crystals, the velvet surface of the front surface of the heterojunction bottom cell is generally polished or micro-velvet treated, which will partially affect the light capture of the bottom cell. In addition, due to the electrical coupling of the top cell and the bottom cell in the integrated configuration, the short-circuit current density (JSC) of the series device is limited by the lowest sub-cell JSC. When the current density difference between the cells on both sides is large, there will be large current losses and heating problems of the battery components. Therefore, strictly meeting the current matching between the sub-cells is the primary challenge in manufacturing 2T stacked solar cells. 4T is composed of two completely independent sub-cells in the circuit structure, and the process is simple, but the 4T stacked structure requires additional transparent electrodes and glass layers, which consumes more in terms of packaging and manufacturing costs, and there is a voltage matching problem that needs to be solved urgently. At present, large-area 2T stacked solar cells have higher preparation difficulty and process control requirements due to problems such as transmission and loss caused by electrical coupling and heterogeneous interfaces.

[0042] In view of the above problems, the embodiment of the present application provides a perovskite laminated photovoltaic cell assembly and a preparation method thereof. The embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0043] See also Figure 1 , Figure 1 This is a simplified structural diagram of a perovskite laminated photovoltaic cell assembly provided in an embodiment of the present application. The perovskite laminated photovoltaic cell assembly includes multiple first battery groups connected in parallel, and a single first battery group includes multiple laminated cell sheets connected in series, wherein a single laminated cell sheet 1 includes stacked perovskite cells 10 and crystalline silicon cells 20, the perovskite cell 10 is located at the top of the laminated cell sheet 1, and the crystalline silicon cell 20 is located at the bottom of the laminated cell sheet 1, the perovskite cell 10 is connected to the first packaging film 120, and the first packaging film 120 is connected to the first packaging substrate 110; the crystalline silicon cell 20 is connected to the second packaging film 220, and the second packaging film 220 is connected to the second packaging substrate 210.

[0044] 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 to absorb 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 a first bottom electrode 105 and a second top electrode 201, and the perovskite cell 10 is used to absorb long-wavelength light in the front sunlight.

[0045] In some embodiments, the first end surface of the first packaging film 120 is bonded to the first end surface of the first top electrode 101, and the second end surface of the first packaging film 120 is bonded to the first end surface of the first packaging substrate 110; the first end surface of the second packaging film 220 is bonded to the first end surface of the second bottom electrode 205, and the second end surface of the second packaging film 220 is bonded to the first end surface of the second packaging substrate 210. The first packaging substrate 110 and the second packaging substrate 210 are glass substrates, and the thicknesses of the first packaging substrate 110 and the second packaging substrate 210 are different.

[0046] 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 oxide includes at least one of ITO, AZO, FTO, and ZnO; the perovskite cell 10 is a thin film cell, the first light absorption layer 103 is a perovskite thin film, the first electron transport layer 102 is an inorganic oxide or an organic semiconductor material, and the first hole transport layer 104 is an organic small molecule material or a polymer material; the crystalline silicon cell 20 is a thin film cell, the second light absorption 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.

[0047] Further, see Figure 3 The first electron transport layer 102, the first light absorption layer 103 and the first hole transport layer 104 are formed into a plurality of parallel perovskite sub-cells through P2 laser scribing, and 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 a one-to-one corresponding series relationship.

[0048] In some embodiments, a first channel is spaced between any two adjacent crystalline silicon sub-cells in the plurality of crystalline silicon sub-cells, a distance between any two adjacent first channels is a first preset distance, and an insulation resistance between any two first channels is greater than or equal to 20 MΩ;

[0049] A second channel is provided between any two adjacent perovskite sub-cells among the plurality of perovskite sub-cells, and a distance between any second channel and an adjacent first channel is a second preset distance.

[0050] In some embodiments, the band gap width of the perovskite cell is 1.65-2.5 eV, which is used to absorb the solar light with a wavelength below 760 nm in the front sunlight; and the band gap width of the crystalline silicon cell is 1.2-1.7 eV, which is used to absorb the solar light with a wavelength between 760-1033 nm in the front sunlight.

[0051] In some embodiments, a first thickness of the first light absorbing layer is 150-450nm, and a 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 the solar light with a wavelength below 760nm in the front sunlight; wherein the light absorption rate includes a first light absorption rate for the solar light in the first band and a second light absorption rate for the solar light in the second band, the first light absorption rate is greater than the second light absorption rate, the first band is 320-460nm, and the second band is 460-760nm.

[0052] It can be seen that in this embodiment, the top cell is mainly 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 band gap width of the bottom cell crystalline silicon cell material is 1.2-1.7eV, which mainly absorbs sunlight with a wavelength below 750-1150nm. In this way, 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.

[0053] 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 the 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. The light E4 is absorbed by the top perovskite cell 10. Among them, the top cell is mainly selected with a band gap width of 1.65-2.5eV. Under standard conditions, the current density is about 23-27mA / cm 2 The perovskite cell 10 mainly absorbs sunlight with a wavelength below 760nm, the thickness of the perovskite layer light absorption layer is 150-450nm, the thickness of the entire top cell film is controlled at 750-1150nm, and the comprehensive absorption rate of the entire top cell to sunlight with a wavelength of 320-460nm is about 80%, the comprehensive absorption rate to sunlight with a wavelength of 460-760nm is about 65%, and the comprehensive absorption rate to sunlight with a wavelength above 760nm is less than 60%.

[0054] Furthermore, the remaining light E3 passes through the top cell into the bottom cell. The band gap width of the bottom cell material is 1.2-1.7 eV. Under standard conditions, the current density is 35-45 mA / cm 2 , can absorb sunlight E5 with a longer wavelength of 760-1033nm, so that they can be optically matched. The top battery mainly absorbs short waves in the sunlight, and the bottom battery mainly absorbs sunlight with a wavelength in the range of 760-1033nm. E6 and E7 represent the light reflected from different batteries. Among them, the lower end of the bottom battery is the positive electrode of the laminated battery cell, represented by the symbol "+", and the upper end of the top battery is the negative electrode of the laminated battery cell, represented by the symbol "-". Structurally, the top battery is equivalent to being irradiated under standard irradiance, and the current density is relatively large. Because of the existence of the top battery, the irradiance received by the bottom battery is lower, and the current density of the battery is not fully stimulated. The overall current density is about 21-24mA / cm 2 .

[0055] It is understandable that under solar irradiance, when a solar cell is irradiated by sunlight, the light absorption layer material of the cell absorbs photons, and the energy of the photons excites the electrons originally bound around the nucleus from the top of the valence band to the bottom of the conduction band, forming free electrons (e-) and holes (h+), i.e., carriers. The carrier concentration is the number of carriers per unit volume, while the current density is the current passing through a cross section perpendicular to the current direction per unit time. In 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 per 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 photogenerated current. The stronger the light, the greater the current generated.

[0056] See also Figure 5 , Figure 5 This is a schematic diagram of electron transmission under front illumination provided in an embodiment of the present application. When P1 is being scratched, the width a of P1 is controlled, and the widths of P1 and P2 are b, and the error is maintained at ±10um.

[0057] Among them, under natural light, the top perovskite cell 10 and the bottom crystalline silicon cell 20 will generate free-moving electrons e -. Because the second top electrode 201 (TCO) and the second hole transport layer 202 (including P-type amorphous silicon and intrinsic hydrogenated amorphous silicon layer) of the bottom battery have been disconnected in the horizontal direction when P1 is scribed, the electrons can only be transmitted in the Z-axis direction. When the electrons of the bottom battery reach the intermediate electrode layer 30, they are combined with the electrons generated by the top battery and continuously transmitted in the top battery to form a current loop. After being collected by the second bottom electrode 205 of the bottom battery, they return to the bottom battery. Therefore, the lower end of the bottom battery is the positive electrode of the laminated battery sheet, represented by the symbol "+", and the upper end of the top battery is the negative electrode of the laminated battery sheet, represented by the symbol "-". At this time, the width of the bottom battery electron transmission in the Z-axis is a, and the width of the top battery electron transmission in the Z-axis is also a. The number of perovskite sub-cells and crystalline silicon sub-cells is a one-to-one series relationship.

[0058] 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 needs to be ≥20MΩ, so that it can be ensured that the electrons can only be transmitted in the Z-axis direction during subsequent electron transmission, 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 battery cell 1, one of metal wires, carbon paste, and silver paste is prepared on the first top electrode 101 and the second bottom electrode 205, and the charges generated by the laminated battery cell 1 are collected by using the excellent conductive properties of the metal wire, carbon paste, and silver paste, and then multiple laminated battery cells 1 are connected together in series or in parallel through bus bars, and finally multiple laminated battery cells 1 are packaged together through upper and lower layers of packaging films to form a perovskite laminated photovoltaic cell module.

[0059] See also Figure 6 , Figure 6 It 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.

[0060] In some embodiments, the current density of the perovskite cell and the crystalline silicon cell are calculated by the following formulas:

[0061] i = J × S (1);

[0062] J = e × α × h × β (2);

[0063] Among them, i is the current density, J is the photocurrent density, S is the battery area, e is the electron charge, α is the absorption coefficient of the material, h is the thickness of the light-absorbing layer, and β is the incident light irradiance.

[0064] Exemplarily, the width of the stacked battery cell is W and the length is L. After P1 and P2 laser scribing, there are M sub-battery groups connected in parallel vertically and N sub-batteries connected in series horizontally. The length of the battery 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 is sbottom=a×d=WL / NM, the area of ​​the top crystalline silicon sub-cell is stop=a×d=WL / NM, the current density of the top perovskite cell is itop=Jtop×stop=Jtop×(LW / NM)=, ibottom=Jbottom×sbottom=Jbottom×(LW / NM).

[0065] Furthermore, combined with the above formula for photocurrent density, it can be seen 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 of the top battery, the irradiance, wavelength, and other parameters of the light passing through the top battery can be controlled, thereby controlling the actual current density of the bottom battery, so that the current of the bottom battery is as equal to or slightly less than the current of the top battery as possible. In this way, the current of the top battery and the bottom battery can be basically consistent under the condition of series connection, achieving the maximum current output.

[0066] See also Figure 7 , Figure 7 1 is a flow chart of a method for preparing a perovskite laminated photovoltaic cell assembly provided in an embodiment of the present application, the method comprising:

[0067] 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.

[0068] Among them, electrical parameters may include voltage, current and fill factor. Specifically, it can be achieved by using professional battery testing equipment to apply a certain voltage or current to the bottom battery, measuring the output voltage, current and other data, and calculating the fill factor and other parameters. 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.

[0069] 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 one-to-one to the plurality of reference electrical parameters.

[0070] Exemplarily, the first preset condition may be that the currents with a difference of less than 0.1 mA are divided into a group, then the reference electrical parameters corresponding to combination A may be: current of approximately 10.0 mA, voltage of 0.6 V, and fill factor of 0.75; the reference electrical parameters corresponding to combination B may be: current of approximately 10.1 mA, voltage of 0.61 V, and fill factor of 0.76; the reference electrical parameters corresponding to combination C may be: current of approximately 10.2 mA, voltage of 0.62 V, and fill factor of 0.77.

[0071] S703, performing the following operations for each of the first combinations 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; and 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; 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 one-to-one with the plurality of crystalline silicon cells to obtain a plurality of stacked cell sheets corresponding to the first combination.

[0072] Among them, the width of P1-P2 laser scribing is mainly 100-200um.

[0073] In some embodiments, before performing the P2 laser scribing on the plurality of perovskite cells respectively according to the second preset distance, the method further includes:

[0074] Determine a second reference distance or a second distance interval according to the reference electrical parameter corresponding to the first combination currently being processed, wherein the second distance interval includes a plurality of values ​​corresponding to the second preset distance;

[0075] 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.

[0076] It is understandable that the width of the P2 laser scribing is not only determined based on the reference electrical parameters, but also related to the thickness of the perovskite battery. The determination of the width of the P1 scribing will affect the position of the P2 scribing, thereby indirectly affecting the width of P1-P2 after the P2 scribing; changes in the thickness of the perovskite battery film layer 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, changes in the thickness of the perovskite light-absorbing layer will affect the generation and transmission of photogenerated carriers, and then affect the electrical characteristics such as the electric field distribution and current density inside the battery. In order to adapt to this performance impact caused by changes in 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.

[0077] For example, for the top-layer battery corresponding to combination A, since the current of the bottom battery is small, in order to achieve current matching, the thickness of the perovskite absorption layer is adjusted to 300nm, the thickness 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-layer battery corresponding to combination B, the thickness of the perovskite absorption layer is adjusted to 320nm, and the thickness of the first electron transport layer and the first hole transport layer changes accordingly. After P2 scratching, the P1-P2 width is 160um; for the top-layer battery corresponding to combination C, the thickness of the perovskite absorption layer is adjusted to 340nm, the thickness of the first electron transport layer and the first hole transport layer are adjusted accordingly, and the P1-P2 width is 170um after P2 scratching.

[0078] S704, determining the plurality of first battery groups according to the plurality of stacked battery cells and a second preset condition.

[0079] In some embodiments, determining the plurality of first battery groups according to the plurality of stacked battery sheets and a second preset condition includes:

[0080] 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;

[0081] 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 for series connection;

[0082] 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.

[0083] It can be seen that after the production of the laminated battery cells is completed, the laminated battery cells will be re-tested for performance and then classified to ensure the series and parallel mode of the subsequent laminated battery cells. Among them, in the selection of series and parallel modes, under the premise of ensuring the maximum power output, series connection and parallel connection are selected according to different classifications. For example, the second preset condition is set to a current difference of less than 0.1mA, and this type of product will be used for series connection later; for example, the third preset condition is set to a voltage difference of less than 0.2mV, and this type of product will be used for parallel connection later. After completing the series and parallel circuit connections of the laminated battery cells, the components are packaged to complete the production process of the photovoltaic cell components.

[0084] S705, respectively connect and package the plurality of first battery groups to obtain the perovskite laminated photovoltaic cell assembly.

[0085] It can be seen that in this embodiment, by first testing the electrical performance of the bottom battery and then classifying it, when preparing the top battery film layer, the electrical performance parameters will be fully relied on to scribe the top battery and adjust the film thickness to control the wavelength, transmittance, irradiance and other parameters of the light passing through the top battery, thereby controlling the actual current density of the bottom battery, so that the current density of the top battery and the bottom battery remain consistent (the current is also consistent), thereby achieving the best series effect. In addition, in this embodiment, reducing unnecessary laser processes can avoid the problem of excessive use of laser scribing, which leads to micro-short circuits in the film layer on the Z axis and reduces component performance.

[0086] See also Figure 8 , Figure 8 It is a circuit diagram of a perovskite stacked cell provided in an embodiment of the present application, wherein the perovskite stacked cell is divided into a plurality of regions, and the plurality of regions are connected in parallel.

[0087] It can be understood that dividing the perovskite stacked cell into multiple parallel regions can ensure that when there is instability in a unit area of ​​the perovskite stacked cell, it will not affect the power generation efficiency of the entire stacked cell.

[0088] Among them, the perovskite stacked cell is divided into M areas.

[0089] Wherein, in the first region, V1 and R1 represent the voltage and internal resistance of the crystalline silicon subcell, v1 and r1 represent the voltage and internal resistance of the perovskite subcell, and in the Mth region, V m , R mRespectively represent the voltage and internal resistance of the crystalline silicon sub-cell, vm, rm represent the voltage and internal resistance of the perovskite sub-cell. In the I region, the currents of the perovskite sub-cell and the crystalline silicon sub-cell are all i1, and the voltage of each group of perovskite sub-cells and crystalline silicon sub-cells connected in series is consistent, that is, the external output voltage is V1+v1, and the output current is i1. Therefore, in the I region, the external output voltage is V1+v1, and the output current is N×i1.

[0090] Furthermore, in areas I to M, the output voltage in each area is V1+v1, and the output current of the entire perovskite stack cell can be approximately equal to M×N×i1, so the output power of the perovskite stack cell P=uout×iout=(V1+v1)×M×N×i1, where uout represents the output voltage of the perovskite stack cell, and iout represents the output current of the perovskite stack cell.

[0091] It can be seen that in this embodiment, the maximum power generation efficiency is achieved by superimposing the perovskite wide bandgap material and the crystalline silicon material. The bandgap of the perovskite material can be regulated by adjusting the material composition and the film thickness, so as to control the absorption wavelength and intensity of the natural light by the light-absorbing layer of the perovskite cell, and control the light intensity and wavelength passing through the perovskite cell, and then control the light intensity and wavelength reaching the crystalline silicon cell. In this way, the density and current density of the photogenerated carriers of the crystalline silicon cell can be adjusted, so that the current density of the top perovskite cell and the current density of the bottom crystalline silicon cell are as consistent as possible; in addition, the intermediate electrode layer and the second hole transport layer are separated by P1 and P2 laser scribing, so that the carriers are transmitted along the Z-axis direction, ensuring the current consistency of the top and bottom cells, and thus solving the problem of excessive loss of electrons in interface transmission caused by the electrical coupling of the perovskite cell and the crystalline silicon cell in the two-terminal (2T) perovskite stacking scheme, which is conducive to improving the power generation efficiency of the perovskite stacked photovoltaic cell assembly.

[0092] Mentioning "embodiment" and "implementation method" in this application means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrases in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments. In addition, it should also be understood that the features, structures or characteristics described in the various embodiments of the present application can be arbitrarily combined to form another embodiment that does not deviate from the spirit and scope of the technical solution of the present application, provided that there is no contradiction between them.

[0093] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the above preferred implementation modes, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A perovskite laminated 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 at the top of the laminated battery sheet, and the crystalline silicon battery is located at the bottom of the laminated battery sheet; wherein, 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 into a plurality of perovskite sub-cells connected 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 which are 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 through 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 in current density between the perovskite cell and the crystalline silicon cell is less than or equal to a first preset value.

2. The perovskite laminated photovoltaic cell assembly according to claim 1, characterized in that: The band gap width of the perovskite cell is 1.65-2.5 eV, and is used to absorb the sunlight with a wavelength below 760 nm in the front sunlight; and The band gap width of the crystalline silicon cell is 1.2-1.7 eV, and is used to absorb the solar light with a wavelength between 760-1033 nm in the front sunlight.

3. The perovskite laminated photovoltaic cell assembly according to claim 2, characterized in that: The first thickness of the first light-absorbing 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 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 band and a second light absorption rate for sunlight in a second band, the first light absorption rate is greater than the second light absorption rate, the first band is 320-460nm, and the second band is 460-760nm.

4. The perovskite laminated photovoltaic cell assembly according to claim 3, characterized in that: A first channel is provided between any two adjacent crystalline silicon sub-cells among the plurality of crystalline silicon sub-cells, a distance between any two adjacent first channels is a first preset distance, and an insulation resistance between any two first channels is greater than or equal to 20 MΩ; A second channel is provided between any two adjacent perovskite sub-cells among the plurality of perovskite sub-cells, and a distance between any second channel and an adjacent first channel is a second preset distance.

5. The perovskite laminated 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 oxides include 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 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.

6. The perovskite laminated photovoltaic cell assembly according to claim 5, characterized in that: The perovskite laminated photovoltaic cell assembly further includes a first packaging film and a first packaging substrate, wherein a first end surface of the first packaging film is bonded to a first end surface of the first top electrode, and a second end surface of the first packaging film is bonded to a first end surface of the first packaging 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. The perovskite laminated photovoltaic cell assembly according to claim 6, characterized in that: The current density of the perovskite cell and the crystalline silicon cell are calculated by the following formulas: i = J × S (1); J = e × α × h × β (2); Among them, i is the current density, J is the photocurrent density, S is the battery area, e is the electron charge, α is the absorption coefficient of the material, h is the thickness of the light-absorbing layer, and β is the incident light irradiance.

8. A method for preparing a perovskite laminated photovoltaic cell assembly, applied to the perovskite laminated photovoltaic cell assembly as claimed in any one of claims 1 to 7, characterized in that: The method comprises: Conducting 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 the 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; Perform the following operations for each of the first combinations to obtain a plurality of stacked cell sheets: determine the first preset distance according to the reference electrical parameters corresponding to the first combination currently being processed, and perform the P1 laser scribing on each crystalline silicon cell in the first combination according to the first preset distance; and determine the first thickness and the second thickness according to the reference electrical parameters, and configure 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; and perform the P2 laser scribing on the plurality of perovskite cells according to the second preset distance; and stack the plurality of perovskite cells one-to-one with the plurality of crystalline silicon cells to obtain a plurality of stacked cell sheets corresponding to the first combination; Determine 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 circuit-connected and packaged to obtain the perovskite laminated photovoltaic cell assembly.

9. The method according to claim 8, characterized in that The step of determining 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 for series connection; 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.

10. The method according to claim 9, characterized in that Before performing the P2 laser scribing on the plurality of perovskite cells respectively according to the second preset distance, the method further includes: Determine a second reference distance or a second distance interval according to the reference electrical parameter corresponding to the first combination currently being processed, wherein 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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