Stacked battery, method of making same, and photovoltaic module

Abstract

The embodiment of the present application relates to the photovoltaic field, and provides a laminated cell, a preparation method thereof and a photovoltaic module, wherein the laminated cell comprises: a first cell; a second cell arranged on the first cell and electrically connected with the first cell; a first electrode arranged on a side of the first cell away from the second cell and electrically connected with the first cell; and a second electrode arranged on a side of the second cell away from the first cell and electrically connected with the second cell; wherein at least one of the first electrode and the second electrode is a flexible electrode, the flexible electrode comprises a plurality of first arc-shaped parts and a plurality of second arc-shaped parts, the first arc-shaped parts are convex in a direction away from the first cell, and the second arc-shaped parts are concave in a direction close to the first cell. The embodiment of the present application can at least improve the bending performance of the laminated cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a tandem cell, its preparation method and photovoltaic module. Background Technology

[0002] Flexible solar cells are a new type of photovoltaic device constructed using lightweight, bendable photovoltaic materials supported by a flexible substrate. Compared with traditional rigid crystalline silicon solar cells, flexible solar cells have significant advantages such as being lightweight, bendable, rollable, impact-resistant, and easy to integrate. They can conform to curved surfaces, breaking through the application scenarios of traditional fixed-installation photovoltaic flat panels and meeting more diverse user needs.

[0003] To overcome the efficiency bottleneck of single-junction photovoltaic cells, tandem cell structures have become a reliable path to improve photoelectric conversion efficiency. Tandem cells vertically stack two or more light-absorbing materials with different band gaps, allowing sunlight of different wavelengths to be absorbed in layers, thereby breaking through the efficiency limit of single-junction cells.

[0004] Combining tandem solar cell technology with flexible solar cell technology to form flexible tandem cells can achieve higher photoelectric conversion efficiency while maintaining high flexibility.

[0005] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0006] This application provides a tandem battery, its preparation method, and a photovoltaic module, which at least helps to improve the bending performance of the tandem battery.

[0007] According to some embodiments of this application, one aspect of this application provides a stacked battery, including: a first battery; a second battery disposed on the first battery and electrically connected to the first battery; a first electrode disposed on the side of the first battery away from the second battery and electrically connected to the first battery; and a second electrode disposed on the side of the second battery away from the first battery and electrically connected to the second battery; wherein at least one of the first electrode and the second electrode is a flexible electrode, the flexible electrode including a plurality of first arcuate portions and a plurality of second arcuate portions, the first arcuate portions protruding in a direction away from the first battery, and the second arcuate portions recessed in a direction closer to the first battery.

[0008] In some embodiments, the plurality of first arcuate portions and the plurality of second arcuate portions are arranged periodically, wherein each periodic unit includes an adjacent first arcuate portion and a second arcuate portion.

[0009] In some embodiments, in a cross-section along the stacking direction of the first and second batteries, the surface of the flexible electrode away from the first battery has a sinusoidal shape.

[0010] In some embodiments, the material of the first arcuate portion includes at least a flexible material, the second arcuate portion includes a first conductive portion and a second conductive portion, the second conductive portion is disposed at least on the surface of the first conductive portion away from the second battery, and the materials of the first conductive portion and the second conductive portion are different.

[0011] In some embodiments, the flexible material includes polyimide, the material of the first conductive portion includes graphene, and the material of the second conductive portion includes metal.

[0012] In some embodiments, the stacked battery further includes a buffer layer disposed between the first battery and the second battery, the buffer layer including a support structure and a plurality of elastic particles embedded within the support structure.

[0013] In some embodiments, the materials of the elastic particles include silicon oxide and polydimethylsiloxane.

[0014] In some embodiments, the plurality of elastic particles are arranged in a hexagonal close-packed array.

[0015] In some embodiments, the stacked battery further includes a first prism array disposed on the side of the second electrode away from the second battery.

[0016] In some embodiments, the first prism array includes a plurality of square pyramidal prisms arranged in an array, the square pyramidal prisms protruding in a direction away from the second battery.

[0017] In some embodiments, the stacked battery further includes a second prism array disposed between the first battery and the first electrode and electrically connected to the first electrode and the first battery, or the second prism array is disposed on the side of the first electrode away from the first battery.

[0018] In some embodiments, the stacked battery satisfies at least one of the following: the first battery includes a first substrate, a first doped layer, and a second doped layer, wherein the first doped layer is disposed on the side of the first substrate near the first electrode and electrically connected to the first electrode, and the second doped layer is disposed on the side of the first substrate near the second battery, and the first doped layer and the second doped layer have different doping types; the second battery includes a second substrate, a first carrier transport layer, and a second carrier transport layer, wherein the first carrier transport layer is disposed on the side of the second substrate near the first battery, and the second carrier transport layer is disposed on the side of the second substrate near the second electrode and electrically connected to the second electrode, and the first carrier transport layer and the second carrier transport layer are used to transport different types of carriers.

[0019] In some embodiments, the thickness of the first substrate is 10~30 μm.

[0020] In some embodiments, the first substrate is a crystalline silicon substrate, and the first substrate further includes graphene and / or helium.

[0021] In some embodiments, the second substrate is a perovskite substrate, and the second substrate further includes a covalently bonded polymer.

[0022] According to some embodiments of this application, another aspect of this application provides a method for fabricating a stacked battery. The method is used to fabricate the stacked battery in any of the above embodiments. The method includes: forming a first electrode; forming a first battery on the first electrode; forming a second battery on the first battery, wherein the first battery and the second battery are electrically connected; and forming a second electrode on the second battery. The step of forming the first electrode and / or the step of forming the second electrode includes forming a flexible electrode. The step of forming the flexible electrode includes: forming a plurality of first arcuate portions and a plurality of second arcuate portions, wherein the first arcuate portions protrude in a direction away from the first battery and the second battery, and the second arcuate portions are recessed in a direction closer to the first battery and the second battery.

[0023] In some embodiments, the step of forming the first arcuate portion and the second arcuate portion includes: forming a flexible material layer on the first battery; performing laser removal and modification on at least a predetermined area of ​​the flexible material layer to obtain the first arcuate portion including a first conductive portion, and the second arcuate portion including the remaining flexible material layer.

[0024] In some embodiments, after laser removal and modification of the flexible material layer in the predetermined area to obtain the first conductive portion, the step of forming the first arc-shaped portion further includes: forming a second conductive portion on the first conductive portion, wherein the first arc-shaped portion includes the first conductive portion and the second conductive portion.

[0025] In some embodiments, after the step of forming the first battery and before the step of forming the second battery, the method for preparing the stacked battery further includes: forming a slurry comprising a plurality of elastic particles on the first battery; pressing the slurry comprising the plurality of elastic particles using a mold, such that the plurality of elastic particles are spaced apart, and any two adjacent elastic particles have the same spacing in the same direction; disposing a slurry comprising a support structure material on the plurality of elastic particles, wherein the slurry of the support structure material encapsulates the plurality of elastic particles; and curing the slurry of the support structure material to form a support structure.

[0026] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including a battery string, which is formed by connecting multiple stacked batteries prepared by any of the above embodiments or by any of the above embodiments' stacked battery preparation methods; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film facing away from the battery string.

[0027] The technical solution provided in this application has at least the following advantages:

[0028] This application relates to the field of photovoltaic technology, providing a tandem battery, its fabrication method, and a photovoltaic module. The tandem battery includes: a first battery; a second battery disposed on and electrically connected to the first battery; a first electrode disposed on the side of the first battery away from the second battery and electrically connected to the first battery; and a second electrode disposed on the side of the second battery away from the first battery and electrically connected to the second battery. At least one of the first electrode and the second electrode is a flexible electrode, which includes a plurality of first arcuate portions and a plurality of second arcuate portions. The first arcuate portions protrude in a direction away from the first battery, and the second arcuate portions are recessed in a direction closer to the first battery. This embodiment of the application sets at least a portion of the electrodes of the tandem battery as the aforementioned flexible electrodes. When the tandem battery is subjected to bending or tensile stress, the flexible electrodes, having a first arc-shaped portion and a second arc-shaped portion, can absorb and disperse local stress through their own deformation. This prevents stress concentration on a single plane or interface, effectively mitigating the risk of fracture due to the brittleness of the electrode material. Simultaneously, it reduces the interfacial stress between the electrode and adjacent functional layers, avoiding delamination or cracking caused by differences in thermal expansion coefficients or mechanical deformation. Therefore, this embodiment of the application, without altering the original film layer composition of the tandem battery, can improve the structural stability and durability of the tandem battery under dynamic bending or deformation by changing the electrode shape; that is, it enhances the bending capability of the tandem battery. Attached Figure Description

[0029] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is one of the structural schematic diagrams of a stacked battery provided according to an embodiment of this application;

[0031] Figure 2 This is a partial structural schematic diagram of a flexible electrode according to an embodiment of this application;

[0032] Figure 3 This is a second schematic diagram of the structure of a stacked battery provided according to an embodiment of this application;

[0033] Figure 4 This is a third schematic diagram of the structure of a stacked battery provided according to an embodiment of this application;

[0034] Figure 5 This is a fourth schematic diagram of the structure of a stacked battery provided according to an embodiment of this application;

[0035] Figure 6 This is a schematic diagram of the structure of a first battery according to an embodiment of this application;

[0036] Figure 7 This is a schematic diagram of the structure of a second battery according to an embodiment of this application;

[0037] Figure 8 This is the fifth schematic diagram of the structure of a stacked battery provided according to an embodiment of this application;

[0038] Figure 9 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of this application.

[0039] The above figures include the following reference numerals:

[0040] 1. First cell; 11. First substrate; 12. First doped layer; 13. Second doped layer; 2. Second cell; 21. Second substrate; 22. First carrier transport layer; 23. Second carrier transport layer; 3. First electrode; 4. Second electrode; 40. Periodic unit; 41. First arc-shaped portion; 42. Second arc-shaped portion; 5. Buffer layer; 51. Support structure; 52. Elastic particle; 6. First prism array; 7. Second prism array; 100. Cell string; 200. Encapsulating film; 300. Cover plate. Detailed Implementation

[0041] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0042] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0043] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0044] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0045] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0046] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0047] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0048] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0049] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0050] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0051] Figure 1 This is a schematic diagram of a stacked battery structure according to an embodiment of this application, as shown below. Figure 1 As shown, the stacked battery includes: a first battery 1, a second battery 2, a first electrode 3, and a second electrode 4. The second battery 2 is disposed on the first battery 1 and electrically connected to the first battery 1; the first electrode 3 is disposed on the side of the first battery 1 away from the second battery 2 and electrically connected to the first battery 1; the second electrode 4 is disposed on the side of the second battery 2 away from the first battery 1 and electrically connected to the second battery 2.

[0052] It should be understood that the above-mentioned electrical connection refers to the fact that the components such as the first battery 1, the second battery 2, the first electrode 3, and the second electrode 4 are conductive. When the stacked battery is in the state of generating or supplying power, the above-mentioned interconnected components can conduct current to achieve electrical connection. In other cases, the above-mentioned electrically connected components may only be in contact with each other without current passing through them.

[0053] It should also be understood that the side where the first battery 1 is located is the side closest to the back of the stacked battery, and the side where the second battery 2 is located is the side closest to the front of the stacked battery. The front of the stacked battery is the side facing the light source (sun) in actual applications. The first electrode 3 is located on the side of the first battery 1 away from the second battery 2, and the second electrode 4 is located on the side of the second battery 2 away from the first battery 1. That is, the first electrode 3 and the second electrode 4 are the electrodes at both ends of the stacked electrode. For example, the first electrode 3 is the top electrode of the stacked battery, and the second battery 2 is the bottom electrode of the stacked battery.

[0054] In the embodiments of this application, at least one of the first electrode 3 and the second electrode 4 is a flexible electrode. This can be either the first electrode 3 or the second electrode 4, or both the first electrode 3 and the second electrode 4 can be flexible electrodes. When only one of the first electrode 3 and the second electrode 4 is a flexible electrode, the other can be a conventional electrode structure, such as a strip electrode. Figure 1 The illustrated embodiment shows the case where the second electrode 4 is a flexible electrode. In the following embodiments, the case where the second electrode 4 is a flexible electrode will be used as an example for explanation.

[0055] Figure 2 This is a partial structural schematic diagram of a flexible electrode according to an embodiment of this application, as shown below. Figure 2 As shown, the flexible electrode includes a plurality of first arc-shaped portions 41 and a plurality of second arc-shaped portions 42. The first arc-shaped portions 41 protrude in a direction away from the first battery 1, and the second arc-shaped portions 42 are recessed in a direction closer to the first battery 1.

[0056] This embodiment of the application sets at least a portion of the electrodes of the tandem battery as the aforementioned flexible electrodes. When the tandem battery is subjected to bending or tensile stress, the flexible electrodes, having a first arc-shaped portion 41 and a second arc-shaped portion 42, can absorb and disperse local stress through their own deformation. This prevents stress concentration on a single plane or interface, effectively mitigating the risk of fracture due to the brittleness of the electrode material. Simultaneously, it reduces the interfacial stress between the electrode and adjacent functional layers, avoiding delamination or cracking caused by differences in thermal expansion coefficients or mechanical deformation. Therefore, this embodiment of the application, without altering the original film layer composition of the tandem battery, can improve the structural stability and durability of the tandem battery under dynamic bending or deformation by changing the electrode shape; that is, it enhances the bending capability of the tandem battery.

[0057] It should be understood that the flexible electrode has a first arc-shaped portion 41 and a second arc-shaped portion 42. The surface of the flexible electrode away from the first battery 1 or the second battery 2 is a curved surface, but the surface of the flexible electrode close to the first battery 1 or the second battery 2 can have a complementary shape to the surface it contacts. For example, when the surface of the battery in contact with the flexible electrode is flat, the surface of the flexible electrode close to the first battery 1 or the second battery 2 is also flat. When the surface of the battery in contact with the flexible electrode is textured, the surface of the flexible electrode close to the first battery 1 or the second battery 2 is also textured, and the two shapes are complementary. Thus, the flexible electrode can achieve continuous and uniform contact with the battery.

[0058] In some embodiments, a plurality of first arcuate portions 41 and a plurality of second arcuate portions 42 are arranged periodically, wherein each periodic unit 40 includes an adjacent first arcuate portion 41 and a second arcuate portion 42. Compared to non-periodic or randomly bent structures, periodic arrangement allows stress to be evenly distributed within each repeating unit, resulting in a more uniform stress distribution rather than concentration at a single weak point. This avoids electrode breakage caused by localized strain concentration. Furthermore, the periodic arrangement structure has high geometric consistency, reducing uncertainties in the electrode fabrication process, which helps to reduce production difficulty and improve yield.

[0059] Reference Figure 2 In some embodiments, in a cross-section along the stacking direction of the first battery 1 and the second battery 2, the surface of the flexible electrode away from the first battery 1 has a sinusoidal shape. The outer surface of the sinusoidal waveform has continuous, non-sharp-cornered, and smoothly curved geometric characteristics. When the battery is subjected to bending, stretching, or cyclic deformation, the stress is uniformly distributed along the surface, avoiding local stress concentration caused by abrupt changes in geometric shape.

[0060] In this embodiment, the period length of the sinusoidal flexible electrode is on the micrometer scale. For example, the period length of the flexible electrode is 200 μm, but it is not limited to this. It is understood that the period length of the flexible electrode can be defined with reference to the period length of a sine wave, that is, the minimum distance at which the waveform repeats in space. For example, Figure 2 The distance D1 between point A and point B in the diagram is the period length of the flexible electrode in the shape of a sine wave.

[0061] In some embodiments, the material of the first arcuate portion 41 includes at least a flexible material, and the second arcuate portion 42 includes a first conductive portion and a second conductive portion. The second conductive portion is at least disposed on the surface of the first conductive portion away from the second battery 2, and the materials of the first conductive portion and the second conductive portion are different. The first arcuate portion 41 uses a flexible material, which can improve the overall bendability and stretchability of the electrode. The second arcuate portion 42 serves as a current conduction channel. The first conductive portion is located on the side closer to the battery and can contact the functional layer in the battery. Its material can be a conductive material that matches the semiconductor interface energy level and has low contact resistance. Part or all of the second conductive portion is located on the surface of the first conductive portion away from the second battery 2, and its material can be a conductive material with high conductivity and low contact resistance, thereby ensuring that the electrode with the above structure has both good flexibility and conductivity. Furthermore, the first conductive portion can use a flexible conductive material, thereby further improving the bending capability of the electrode.

[0062] In some embodiments, the first conductive portion can be formed by modifying the material used for the first arc-shaped portion 41. In this way, the first conductive portions in the first arc-shaped portion 41 and the second arc-shaped portion 42 are arranged in the same layer and continuously, and both are flexible. This can improve the flexibility of the electrode and reduce the risk of interlayer structure separation due to insufficient interfacial bonding force.

[0063] In some embodiments, the first conductive portion can be a porous structure, so that the second conductive portion can extend into the holes in the first conductive portion. The high conductivity of the second conductive portion can further improve the current transmission capability of the electrode. Furthermore, a portion of the structure of the second conductive portion is embedded in the first conductive portion. The interlacing of the first and second conductive portions can achieve a more reliable connection, further improving the reliability of the stacked battery when bent.

[0064] In some embodiments, the portion of the second conductive part located in the hole of the first conductive part can be embedded in the hole in the form of a nanowire. In this way, when the electrode is stretched or bent, the flexible and porous first conductive part can deform, and the portion of the second conductive part embedded in the hole can also be extended, straightened or slightly bent. Because it is a dispersed linear structure, it is not easy to form a through-break, thereby further improving the bending capability of the stacked battery.

[0065] In some embodiments, the flexible material includes polyimide (PI), the material of the first conductive portion includes graphene, and the material of the second conductive portion includes metal.

[0066] In the above embodiments, the graphene in the first conductive part can be formed by laser-induced PI modification. By irradiating a portion of the PI surface with a laser, a depression is formed on the PI surface. At the same time, the remaining PI in this area is modified into conductive graphene, which has both flexibility and conductivity. Furthermore, during the laser modification process, a porous structure can be formed inside the graphene. Thus, when a second conductive part of metal is formed on the first conductive part, the metal can enter the porous structure of the graphene to form a linear structure. The cured metal is interwoven with the graphene framework and can also deform when the electrode is bent, avoiding problems such as electrode breakage.

[0067] In the above embodiments, the metal may exemplary be copper or silver.

[0068] Figure 3 This is a schematic diagram of another stacked battery structure provided according to an embodiment of this application, as shown below. Figure 3 As shown, the stacked battery also includes a buffer layer 5, which is disposed between the first battery 1 and the second battery 2. The buffer layer 5 includes a support structure 51 and a plurality of elastic particles 52 embedded in the support structure 51. In this embodiment, by providing a buffer layer 5 with elastic particles 52 between the first battery 1 and the second battery 2, the elastic particles 52 act as local stress relief units, undergoing controllable compression and deformation under bending stress, thereby achieving spatial redistribution of stress and energy dissipation, and thus improving the bending resistance of the stacked structure.

[0069] In some embodiments, the elastic particles 52 described above may include a shell and a filling portion filled within the shell. The hardness of the shell is greater than that of the filling portion, thereby providing protection for the filling portion, while the filling portion can disperse stress when the stacked battery deforms. Furthermore, the thickness of the shell may be less than the thickness of the filling portion to prevent the overall hardness of the elastic particles 52 from being too high, which could lead to failure when the stacked battery bends.

[0070] In some embodiments, the material of the elastic particles 52 includes silicon oxide (SiOx) and polydimethylsiloxane (PDMS). Silicon oxide serves as the outer shell of the elastic particles 52, acting as a protective layer to improve the reliability of the elastic particles 52 during preparation or use. PDMS is disposed inside the silicon oxide shell, possessing better resilience and capable of reversible compression when the stacked battery is bent. Thus, in the above embodiments, the silicon oxide shell prevents the particles from being crushed or stuck together, while the PDMS core ensures that they can recover their original shape under repeated deformation.

[0071] In some embodiments, the elastic particle 52 may have a cavity inside, meaning the filling portion can be air. When the elastic particle 52 is subjected to an external force, the volume of the cavity is compressed to absorb energy and release stress. Compared to a solid particle of the same outer diameter, the hollow portion has a lower elastic modulus. Therefore, during the bending process of the stacked battery, the hollow elastic particle 52 preferentially deforms, achieving the transfer and dissipation of localized stress.

[0072] In some embodiments, the multiple elastic particles 52 are arranged in a hexagonal close-packed (HCP) array. The multiple elastic particles 52 arranged in the hexagonal close-packed array include multiple layers of stacked elastic particles 52, with the center point of each elastic particle 52 forming a regular hexagonal arrangement with the center points of the six nearest surrounding particles. This arrangement can maximize the use of space, allowing a sufficient number of elastic particles 52 to be placed in the buffer layer 5, thereby greatly improving the bending capability of the stacked battery.

[0073] In such Figure 3 In the illustrated embodiment, the support structure 51 of the buffer layer 5 can be made of a light-transmitting flexible material to further enhance the deformation capability of the buffer layer 5 while reducing the loss of incident light. For example, the support structure 51 of the buffer layer 5 can be made of acrylic resin.

[0074] Figure 4 This is a schematic diagram of another stacked battery structure provided according to an embodiment of this application, as shown below. Figure 4 As shown, the stacked battery may further include a first prism array 6, which is disposed on the side of the second electrode 4 away from the second battery 2. In this embodiment, by distributing the first prism array 6 on the front side of the stacked battery, light incident on the first prism array 6 undergoes multiple refractions and reflections on the prism surface, ultimately allowing more light to be guided into the first battery 1 for absorption and utilization, thereby improving the conversion efficiency of the stacked battery.

[0075] In some embodiments, the first prism array 6 includes a plurality of square pyramidal prisms arranged in an array, the square pyramidal prisms protruding away from the second battery 2. The square pyramidal prisms have a plurality of inclined surfaces with their apexes connected. When light is incident on the inclined surfaces, it may be directly transmitted to the first incident surface or reflected to other inclined surfaces. After at least one reflection, it enters the first battery 1, thereby allowing more light to enter the first battery 1 and be utilized.

[0076] In some embodiments, the first prism array 6 described above can be formed of PDMS material, so that the first prism array 6 can also help to bear stress, which is beneficial to further improve the bending ability of the stacked battery.

[0077] Figure 5 This is a schematic diagram of another stacked battery structure provided according to an embodiment of this application, as shown below. Figure 5 As shown, in some embodiments, the stacked battery further includes a second prism array 7, which is disposed between the first battery 1 and the first electrode 3 and electrically connected to both the first electrode 3 and the first battery 1. The second prism array 7 is located near the back side of the stacked battery and can reflect light incident from the second battery 2 side and exiting from the first battery 1 side back into the stacked battery for utilization, improving the utilization rate of incident light and increasing the probability of light entering from the back side of the stacked battery, thereby improving the photoelectric conversion efficiency of the stacked battery.

[0078] When the second prism array 7 is disposed between the first electrode 3 and the first battery 1, the second prism array 7 is electrically connected to both the first electrode 3 and the first battery 1. This can be achieved by forming the second prism array 7 using a conductive material. In some embodiments, the second prism array 7 includes a prism layer and an auxiliary conductive layer. The prism layer includes multiple prisms, such as a four-sided pyramidal prism. The auxiliary conductive layer covers the surface of the prism away from the first battery 1. The prism layer can be made of a conductive material, such as a semiconductor material, to ensure normal current transmission. The auxiliary conductive layer can be made of a metal to improve conductivity. Exemplarily, the material of the second prism array 7 can include zinc oxide (ZnO) and silver, with zinc oxide forming the prism layer and silver forming the auxiliary conductive layer.

[0079] In some other embodiments, the second prism array may also be disposed on the side of the first electrode away from the first battery (not shown in the figure) to improve the utilization rate of front incident light and the probability of back incident light, thereby improving the photoelectric conversion efficiency of the stacked battery.

[0080] Figure 6 This is a schematic diagram of the structure of a first battery according to an embodiment of this application, with reference to... Figure 1 and Figure 6 The first battery 1 includes a first substrate 11, a first doped layer 12 and a second doped layer 13. The first doped layer 12 is disposed on the side of the first substrate 11 near the first electrode 3 and is electrically connected to the first electrode 3. The second doped layer 13 is disposed on the side of the first substrate 11 near the second battery 2. The first doped layer 12 and the second doped layer 13 have different doping types.

[0081] The first substrate 11 mentioned above can be a silicon substrate. One of the first doped layer 12 and the second doped layer 13 is an N-type doped layer and the other is a P-type doped layer. The doping element of the N-type doped layer is at least one of nitrogen, phosphorus, arsenic, antimony, bismuth, etc., and the doping element of the P-type doped layer is at least one of boron, aluminum, gallium, indium, thallium, etc.

[0082] In some embodiments, the thickness of the first substrate 11 is 10~30μm, making the first substrate 11 thinner than the conventional silicon substrate of 100~300μm, which is more conducive to bending.

[0083] In some embodiments, the first substrate 11 is a crystalline silicon substrate, and the first substrate 11 further includes at least one of graphene and helium. By incorporating graphene into the crystalline silicon substrate, a stress-dispersing network can be formed, allowing the crystalline silicon substrate to remain effective even after more bends. Injecting helium ions into the crystalline silicon substrate can induce dislocation buffering of mechanical stress, improve the toughness of the crystalline silicon substrate, and thus improve the bending performance of the tandem solar cell.

[0084] In some embodiments, a tunneling oxide layer (not shown in the figure) may also be provided between the first substrate 11 and the first doped layer 12 to reduce carrier recombination loss.

[0085] Figure 7 This is a schematic diagram of the structure of a second battery according to an embodiment of this application, with reference to... Figure 1 and Figure 7 The second battery 2 includes a second substrate 21, a first carrier transport layer 22, and a second carrier transport layer 23. The first carrier transport layer 22 is disposed on the side of the second substrate 21 close to the first battery 1, and the second carrier transport layer 23 is disposed on the side of the second substrate 21 close to the second electrode 4 and is electrically connected to the second electrode 4. The first carrier transport layer 22 and the second carrier transport layer 23 are used to transport different types of carriers.

[0086] The second substrate 21 mentioned above can be a perovskite substrate, and one of the first carrier transport layer 22 and the second carrier transport layer 23 is used to transport electrons and the other is used to transport holes.

[0087] In some embodiments, the second substrate 21 is a perovskite substrate, and the second substrate 21 further includes a covalently bonded polymer. By embedding a covalently bonded polymer in the perovskite substrate, the polymer chain slippage disperses stress when the battery is bent, and the molecular bonds spontaneously recombine after bending to repair perovskite grain boundary cracks, thereby improving the recovery ability of the second battery 2 in multiple bends and further enhancing the bending capability of the stacked battery.

[0088] It should be understood that the flexible electrode, buffer layer 5, first prism array 6, and second prism array 7 in the above embodiments, or combinations thereof, can be simultaneously disposed in the stacked battery to enable the stacked battery to obtain their respective corresponding effect gains. These will not be listed one by one in this application. Figure 8 This is a schematic diagram of another stacked battery structure provided according to an embodiment of this application, as shown below. Figure 8As shown, in a specific embodiment of this application, the first battery 1 can be a TOPCon battery, and the second battery 2 can be a perovskite battery. The first battery 1 includes a first substrate 11, a first doped layer 12, and a second doped layer 13. The first substrate 11 is a crystalline silicon substrate, and the first and second doped layers 12 and 13 are nanocrystalline silicon doped layers. A tunneling oxide layer (not shown in the figure) is disposed between the first doped layer 12 and the first substrate 11, and between the second doped layer 13 and the first substrate 11. The second battery 2 includes a second substrate 21, a first carrier transport layer 22, and a second carrier transport layer 23. Furthermore, a buffer layer 5 is disposed between the first battery 1 and the second battery 2; a first electrode 3 is disposed on the side of the first battery 1 away from the second battery 2 and is a conventional strip electrode; a second electrode 4 is disposed on the side of the second battery 2 away from the first battery 1 and is a flexible electrode; a first prism array 6 is disposed on the side of the second electrode 4 away from the second battery 2; and a second prism array 7 is disposed between the first battery 1 and the first electrode 3. The stacked battery in the above embodiments can significantly improve the bending performance of the battery, while also increasing the battery's light utilization rate, thereby improving the battery's photoelectric conversion efficiency.

[0089] Based on the same concept, another aspect of this application provides a method for preparing a stacked battery. This method is used to prepare the stacked battery in any of the above embodiments, and the method includes the following steps S1 to S4:

[0090] Step S1: Form the first electrode 3;

[0091] Step S2: Form the first cell 1 on the first electrode 3;

[0092] Step S3: Form a second battery 2 on the first battery 1, and electrically connect the first battery 1 and the second battery 2.

[0093] Step S4: Form a second electrode 4 on the second battery 2.

[0094] The steps of forming the first electrode 3 and / or forming the second electrode 4 include forming a flexible electrode. The steps of forming the flexible electrode include forming a plurality of first arc-shaped portions 41 and a plurality of second arc-shaped portions 42, wherein the first arc-shaped portions 41 protrude in a direction away from the first battery 1 and the second battery 2, and the second arc-shaped portions 42 are recessed in a direction closer to the first battery 1 and the second battery 2.

[0095] In some embodiments, a first battery 1 and a second battery 2 may be formed first, and then the first battery 1 and the second battery 2 may be connected. Subsequently, a first electrode 3 may be formed on the side of the first battery 1 away from the second battery 2, and a second electrode 4 may be formed on the side of the second battery 2 away from the first battery 1. The following embodiments will be described using the case in which the preparation method includes the above steps S1 to S4 as an example.

[0096] In some embodiments, the step of forming the first arcuate portion 41 and the second arcuate portion 42 (i.e., the step of forming the flexible electrode) includes the following steps S11 and S12:

[0097] Step S11: Form a flexible material layer on the first battery 1;

[0098] Step S12: At least the flexible material layer in the predetermined area is laser removed and modified to obtain a first arc-shaped portion 41 including a first conductive portion, and a second arc-shaped portion 42 including the remaining flexible material layer.

[0099] In steps S11 and S12 above, the flexible material layer can be made of PI. PI itself is an insulating plastic. When the surface of the PI material layer is irradiated by a laser in step S12, the laser can remove the hydrogen and oxygen elements in the PI, leaving only carbon elements. These carbon atoms can be rearranged into honeycomb-shaped graphene to conduct electricity. Furthermore, only a portion of the flexible material layer that has been irradiated by the laser is removed, i.e., non-penetrating processing is performed using the laser. The remaining portion is the first conductive part mentioned above.

[0100] In some embodiments, after laser removal and modification of the flexible material layer within a predetermined area to obtain the first conductive portion, the step of forming the first arc-shaped portion 41 further includes:

[0101] Step S13: A second conductive portion is formed on the first conductive portion, and the first arc-shaped portion 41 includes the first conductive portion and the second conductive portion.

[0102] In step S13 above, the second conductive part can be made of metal. Since the carbon atoms in the first conductive part are rearranged into a sparse graphene structure, i.e., the first conductive part has a porous structure, the second conductive part can partially extend into the pores of the first conductive part and interweave with it, further improving the conductivity and anti-breakage properties of both. For example, AgNWs solution can be used to fill the laser-modified area (i.e., the first conductive part), followed by hot pressing to form silver nanowires as the second conductive part.

[0103] In some embodiments, a plurality of the first arcuate portions 41 and a plurality of the second arcuate portions 42 described above are interconnected to form a flexible electrode with a sinusoidal waveform, the sinusoidal waveform being achieved by setting the motion path of the laser.

[0104] In some embodiments, taking the case where only the second electrode 4 is the flexible electrode described above as an example, in step S1 above, the first electrode 3 can be formed on a flexible substrate (e.g., PI) using a roll-to-roll electrodeposition process with a highly conductive metal material (e.g., copper), thereby further improving the bending performance of the tandem battery.

[0105] In some embodiments, the step of forming the first battery 1 (i.e., step S2) may include forming a first doped layer 12, a first substrate 11, and a second doped layer 13. The formation process of the first substrate 11 may include a thinning process, and the first doped layer 12 and the second doped layer 13 may be formed by a deposition process. Exemplarily, the first substrate 11 may be formed using a reactive ion etching (RIE) thinning process, and the first doped layer 12 and the second doped layer 13 may be formed using a chemical vapor deposition (CVD) process.

[0106] After forming the first doped layer 12 and before forming the first substrate 11, and after forming the first substrate 11 and before forming the second doped layer 13, a tunneling oxide layer may also be formed, which may be formed using plasma oxidation.

[0107] In some embodiments, after the step of forming the first battery 1 and before the step of forming the second battery 2, the method for preparing the stacked battery further includes forming a buffer layer 5, and the step of forming the buffer layer 5 further includes the following steps S21 to S24:

[0108] Step S21: Form a slurry comprising a plurality of elastic particles 52 on the first battery 1;

[0109] Step S22: Use a mold to press a paste containing multiple elastic particles 52, so that the multiple elastic particles 52 are arranged at intervals, and the spacing between any two adjacent elastic particles 52 in the same direction is the same.

[0110] Step S23: Apply a slurry containing a supporting structural material to multiple elastic particles 52, wherein the slurry of the supporting structural material encapsulates the multiple elastic particles 52.

[0111] Step S24: The slurry of the solidified support structure material forms the support structure 51.

[0112] In step S21 above, a slurry including multiple elastic particles 52 can be formed on the first battery 1 by spin coating; in step S22 above, a mold can be used to imprint the slurry including multiple elastic particles 52, so that the elastic particles 52 are arranged in a hexagonal close-packed array; in step S23 above, the support structure material can be an acrylate precursor; in step S24, ultraviolet light (UV light) can be used to cure the slurry; after completing step S24 above, the cured support structure 51 can be polished to provide a smooth surface for the subsequent formation of the second battery 2.

[0113] In some embodiments, the step of forming the second battery 2 includes forming a first carrier transport layer 22, forming a second substrate 21, and forming a second carrier transport layer 23. Exemplarily, the first carrier transport layer 22 can be formed using NiO through a physical vapor deposition (PVD) process, the second substrate 21 can be formed using a perovskite material (e.g., CsPbI3) through a spin coating process, and the second carrier transport layer 23 can be formed using SnO2 through an atomic layer deposition (ALD) process.

[0114] In some embodiments, when forming the second perovskite substrate 21, graphene quantum dots may be doped therein, or helium atoms may be injected, to enhance the recovery ability of the second substrate 21 after being bent.

[0115] In some embodiments, after forming the second electrode 4, the above-described fabrication method may further include forming a first prism array 6. Exemplarily, the first prism array 6 may be fabricated using PDMS material via a soft photolithography transfer process.

[0116] Based on the same concept, this application embodiment further provides a photovoltaic module. Figure 9 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of this application, as shown below. Figure 9 As shown, the photovoltaic module includes a cell string 100, an encapsulating film 200, and a cover plate 300.

[0117] The battery string 100 described above is formed by connecting multiple stacked batteries from any of the above embodiments or stacked batteries prepared by the method of preparing stacked batteries from any of the above embodiments. The connection method can be series, parallel, or a combination of series and parallel, and is not limited here.

[0118] The encapsulating film 200 is used to cover the surface of the battery string 100, isolating the battery string 100 from the external environment and preventing moisture and oxygen from corroding the solar cells. This can improve the reliability of the photovoltaic module and extend its service life. The encapsulating film 200 can be made of, but is not limited to, ethylene-vinyl acetate copolymer (EVA) film, polyolefin elastomer (POE) film, etc.

[0119] The cover plate 300 is used to cover the surface of the encapsulating film 200 away from the cell string 100. It can be used to protect the internal structure of the photovoltaic module and improve the reliability of the photovoltaic module. The cover plate 300 can be made of materials with high hardness and good light transmittance, such as glass, so as to provide protection for the photovoltaic module while allowing as much light as possible to enter the cell string 100 and be utilized.

[0120] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A stacked battery, characterized in that, include: First battery; The second battery is disposed on the first battery and electrically connected to the first battery; The first electrode is disposed on the side of the first battery away from the second battery and is electrically connected to the first battery; The second electrode is disposed on the side of the second battery away from the first battery and is electrically connected to the second battery; Wherein, at least one of the first electrode and the second electrode is a flexible electrode, the flexible electrode includes a plurality of first arc-shaped portions and a plurality of second arc-shaped portions, the first arc-shaped portions protrude in a direction away from the first battery, the second arc-shaped portions are recessed in a direction closer to the first battery, the material of the first arc-shaped portions includes at least a flexible material, the second arc-shaped portions include a first conductive portion and a second conductive portion, the second conductive portion is at least disposed on the surface of the first conductive portion away from the second battery, and the materials of the first conductive portion and the second conductive portion are different.

2. The stacked battery according to claim 1, characterized in that, The plurality of first arc-shaped portions and the plurality of second arc-shaped portions are arranged periodically, wherein each periodic unit includes an adjacent first arc-shaped portion and a second arc-shaped portion.

3. The stacked battery according to claim 2, characterized in that, In a cross-section along the stacking direction of the first and second batteries, the surface of the flexible electrode away from the first battery has a sinusoidal shape.

4. The stacked battery according to claim 1, characterized in that, The flexible material includes polyimide, the material of the first conductive part includes graphene, and the material of the second conductive part includes metal.

5. The stacked battery according to claim 1, characterized in that, The stacked battery further includes a buffer layer disposed between the first battery and the second battery. The buffer layer includes a support structure and a plurality of elastic particles embedded in the support structure.

6. The stacked battery according to claim 5, characterized in that, The materials of the elastic particles include silicon dioxide and polydimethylsiloxane.

7. The stacked battery according to claim 5, characterized in that, The multiple elastic particles are arranged in a hexagonal close-packed array.

8. The stacked battery according to claim 1, characterized in that, The stacked battery also includes a first prism array, which is disposed on the side of the second electrode away from the second battery.

9. The stacked battery according to claim 8, characterized in that, The first prism array includes a plurality of square pyramidal prisms arranged in an array, the square pyramidal prisms protruding in a direction away from the second battery.

10. The stacked battery according to claim 1, characterized in that, The stacked battery further includes a second prism array, which is disposed between the first battery and the first electrode and electrically connected to the first electrode and the first battery, or the second prism array is disposed on the side of the first electrode away from the first battery.

11. The stacked battery according to claim 1, characterized in that, The stacked battery satisfies at least one of the following: The first battery includes a first substrate, a first doped layer, and a second doped layer. The first doped layer is disposed on the side of the first substrate near the first electrode and is electrically connected to the first electrode. The second doped layer is disposed on the side of the first substrate near the second battery. The first doped layer and the second doped layer have different doping types. The second battery includes a second substrate, a first carrier transport layer and a second carrier transport layer. The first carrier transport layer is disposed on the side of the second substrate close to the first battery, and the second carrier transport layer is disposed on the side of the second substrate close to the second electrode and electrically connected to the second electrode. The first carrier transport layer and the second carrier transport layer are used to transport different types of carriers.

12. The stacked battery according to claim 11, characterized in that, The thickness of the first substrate is 10~30μm.

13. The stacked battery according to claim 11, characterized in that, The first substrate is a crystalline silicon substrate, and the first substrate further includes graphene and / or helium.

14. The stacked battery according to claim 11, characterized in that, The second substrate is a perovskite substrate, and the second substrate also includes a covalently bonded polymer.

15. A method for preparing a stacked battery, characterized in that, The method for preparing the stacked battery is used to prepare the stacked battery as described in any one of claims 1 to 14, wherein the method for preparing the stacked battery includes: Form the first electrode; A first cell is formed on the first electrode; A second battery is formed on the first battery, and the first battery and the second battery are electrically connected; A second electrode is formed on the second battery; The step of forming the first electrode and / or the step of forming the second electrode includes forming a flexible electrode. The step of forming the flexible electrode includes forming a plurality of first arc-shaped portions and a plurality of second arc-shaped portions, wherein the first arc-shaped portions protrude in a direction away from the first battery and the second battery, and the second arc-shaped portions are recessed in a direction closer to the first battery and the second battery.

16. The method for preparing a stacked battery according to claim 15, characterized in that, The steps of forming the first arc-shaped portion and the second arc-shaped portion include: A flexible material layer is formed on the first battery; At least the flexible material layer within the predetermined area is laser-removed and modified to obtain the first arc-shaped portion including the first conductive portion, and the second arc-shaped portion including the remaining flexible material layer.

17. The method for preparing a stacked battery according to claim 16, characterized in that, After laser removal and modification of the flexible material layer within the predetermined area to obtain the first conductive portion, the step of forming the first arc-shaped portion further includes: A second conductive portion is formed on the first conductive portion, and the first arc-shaped portion includes the first conductive portion and the second conductive portion.

18. The method for preparing a stacked battery according to claim 15, characterized in that, The method for preparing the stacked battery, after the step of forming the first battery and before the step of forming the second battery, further includes: A slurry comprising multiple elastic particles is formed on the first battery; The paste comprising multiple elastic particles is pressed using a mold, such that the multiple elastic particles are arranged at intervals, and any two adjacent elastic particles have the same spacing in the same direction. A slurry comprising a supporting structural material is disposed on the plurality of elastic particles, the slurry of the supporting structural material encapsulating the plurality of elastic particles; The slurry that solidifies the supporting structure material forms the supporting structure.

19. A photovoltaic module, characterized in that, include: A battery string is formed by connecting multiple stacked batteries as described in any one of claims 1 to 14 or by the method of preparing stacked batteries as described in any one of claims 15 to 18. An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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