Solar cell module and voltage matching method and apparatus therefor

Abstract

Disclosed in the present invention are a solar cell module and a voltage matching method and apparatus therefor. The voltage matching method comprises: determining an output voltage of a top cell; determining a target output voltage of a bottom cell on the basis of the output voltage of the top cell; determining the bottom sub-cell width of each bottom sub-cell of the bottom cell on the basis of the target output voltage of the bottom cell, the cell width of the bottom cell, and a bottom sub-cell open-circuit voltage of each bottom sub-cell comprised in the bottom cell, wherein the bottom cell comprises a plurality of bottom sub-cells connected in series; and determining an actual output voltage of the bottom cell on the basis of the bottom sub-cell width of each bottom sub-cell, the cell width of the bottom cell, and the bottom sub-cell open-circuit voltage of each bottom sub-cell comprised in the bottom cell, so that a voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell is less than a preset value. The present invention can improve the photoelectric conversion efficiency of solar cell modules.

Description

A solar cell module and its voltage matching method and apparatus Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a solar cell module and its voltage matching method and apparatus. Background Technology

[0002] Currently, in the research and development of most stacked batteries on the market, this structure is equivalent to a series connection. The main issue to consider is the limited magnitude of the short-circuit current of the entire battery. To match the short-circuit current of the upper and lower batteries, it is necessary to match their band gaps to achieve balance. The process is quite complicated and the matching window is narrow.

[0003] Another approach is to use a stacked battery solution with two types of batteries mechanically stacked. Considering the open-circuit voltage of modules of the same area, to physically match the voltage of the top cell, the bottom cell needs to be made of 6- or 7-cell or smaller cells connected in series to achieve a voltage value similar to that of the top cell. This results in a significant loss of efficiency for the bottom cell during the cutting process. Summary of the Invention

[0004] This invention provides a solar cell module and its voltage matching method and apparatus, which can improve the photoelectric conversion efficiency of the solar cell module.

[0005] According to one aspect of the present invention, a voltage matching method for a solar cell module is provided, the solar cell module comprising: a bottom cell and a top cell stacked sequentially; the voltage matching method comprising:

[0006] Determine the output voltage of the top battery;

[0007] Determine the target output voltage of the bottom battery based on the output voltage of the top battery;

[0008] The base cell width of each base cell in the base battery is determined based on the target output voltage of the base battery, the base battery width, and the base cell opening voltage of each base cell included in the base battery; wherein, the base battery includes multiple base cells connected in series.

[0009] The actual output voltage of the bottom battery is determined based on the width of each bottom battery, the battery width of the bottom battery, and the opening voltage of each bottom battery included in the bottom battery, so that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

[0010] Optionally, the default value is 10% of the top battery's output voltage.

[0011] Optionally, the bottom and top batteries can have the same width.

[0012] Optionally, the base cell width of each base cell in the base battery is determined based on the target output voltage of the base battery, the cell width of the base battery, and the base cell opening voltage of each base cell included in the base battery, including:

[0013] The number of base cells is determined based on the target output voltage of the battery and the base cell opening voltage of each base cell included in the base cell;

[0014] The width of each base cell in the base battery is determined based on the number of base cells and the width of the base cells.

[0015] Optionally, the base cell includes a central region and a packaging region, with the packaging region surrounding the central region and the base cell located in the central region;

[0016] The width of each base cell in the base battery is determined based on the number of base cells and the width of the base cells, including:

[0017] The width of the base cell is determined based on the width of the base cell, the number of base cells, and the preset dimensions of the packaging area.

[0018] Optionally, determine the output voltage of the top battery, including:

[0019] The output voltage of the top battery is determined based on the width of the top battery, the width of each sub-battery of the top battery, and the opening voltage of each sub-battery; wherein, the top battery comprises multiple sub-batteries connected in series.

[0020] Optionally, the top cell includes a central region and a packaging region, with the packaging region surrounding the central region, and all top cells located in the central region;

[0021] The output voltage of the top battery is determined based on the width of the top battery, the width of each sub-cell of the top battery, and the opening voltage of each sub-cell, including:

[0022] The number of top cells is determined based on the width of the top cell, the preset size of the encapsulation area, and the width of the top cell.

[0023] The output voltage of the top battery is determined based on the number of top batteries and the opening voltage of the top batteries.

[0024] Optionally, the bottom cell is a copper indium gallium selenide (CIGS) cell; the CIGS cell includes a first substrate, a back electrode, a CIGS absorber layer, a buffer layer and a third conductive layer stacked sequentially.

[0025] The top cell is a perovskite cell; the perovskite cell includes a second substrate, a first conductive layer, a first carrier transport layer, a perovskite absorber layer, a second carrier transport layer and a second conductive layer stacked in sequence; the second substrate is located on the side of the first conductive layer away from the first substrate.

[0026] According to another aspect of the present invention, a voltage matching device for a solar cell module is provided. The solar cell module includes: a bottom cell and a top cell stacked sequentially; the voltage matching device includes:

[0027] The first voltage determination module is used to determine the output voltage of the top battery;

[0028] The second voltage determination module is used to determine the target output voltage of the bottom battery based on the output voltage of the top battery.

[0029] A width determination module is used to determine the width of each base cell of the bottom battery based on the target output voltage of the bottom battery, the width of the bottom battery, and the base cell opening voltage of each base cell included in the bottom battery; wherein, the bottom battery includes multiple base cells connected in series.

[0030] The third voltage determination module is used to determine the actual output voltage of the bottom battery based on the width of each bottom battery, the battery width of the bottom battery, and the open voltage of each bottom battery included in the bottom battery, so that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

[0031] According to another aspect of the present invention, a solar cell module is provided, which is formed using the voltage matching method and / or the voltage matching device described in any embodiment of the present invention.

[0032] The present invention provides a voltage matching method for a solar cell module, wherein the solar cell module includes a bottom cell and a top cell stacked sequentially; the voltage matching method includes: determining the output voltage of the top cell; determining the target output voltage of the bottom cell based on the output voltage of the top cell; determining the width of each bottom cell of the bottom cell based on the target output voltage of the bottom cell, the width of the bottom cell, and the open voltage of each bottom cell included in the bottom cell; wherein the bottom cell includes multiple bottom cells connected in series; determining the actual output voltage of the bottom cell based on the width of each bottom cell, the width of the bottom cell, and the open voltage of each bottom cell included in the bottom cell, such that the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell is less than a preset value. This invention can control the actual output voltage of the bottom cell by adjusting the width of each bottom cell, so that the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell is less than a preset value. This makes the voltages of the bottom cell and the top cell match, thereby improving the photoelectric conversion efficiency of the solar cell module. Because the voltage difference between the bottom cell and the top cell is not large, the photoelectric conversion efficiency will not decrease due to a large voltage difference between the bottom cell and the top cell, thus improving the photoelectric conversion efficiency of the solar cell module.

[0033] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 is a flowchart of a voltage matching method for a solar cell module provided in an embodiment of the present invention.

[0036] Figure 2 is a schematic diagram of the structure of a top battery provided in an embodiment of the present invention.

[0037] Figure 3 is a detailed flowchart of S130 in Figure 1.

[0038] Figure 4 is a flowchart of another voltage matching method for a solar cell module provided by an embodiment of the present invention.

[0039] Figure 5 is a schematic diagram of a solar cell module provided in an embodiment of the present invention.

[0040] Figure 6 is a detailed flowchart of S210 in Figure 4.

[0041] Figure 7 is a schematic diagram of the structure of a solar cell module provided in an embodiment of the present invention.

[0042] Figure 8 is a schematic diagram of a voltage matching device for a solar cell module provided in an embodiment of the present invention.

[0043] Figure 9 is a schematic diagram of the width determination module provided in an embodiment of the present invention.

[0044] Figure 10 is a schematic diagram of the width determination submodule provided in an embodiment of the present invention.

[0045] Figure 11 is a schematic diagram of the first voltage determination module provided in an embodiment of the present invention.

[0046] Figure 12 is a schematic diagram of the first voltage determination submodule provided in an embodiment of the present invention. Embodiments of the present invention

[0047] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms "first," "second," etc., used in this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] This invention provides a voltage matching method for a solar cell module, the solar cell module comprising: a bottom cell and a top cell stacked sequentially; Figure 1 is a flowchart of a voltage matching method for a solar cell module provided by this invention. Referring to Figure 1, the voltage matching method includes:

[0050] S110, Determine the output voltage of the top battery.

[0051] The top cell can be a perovskite cell. Figure 2 is a schematic diagram of the structure of a top cell provided in an embodiment of the present invention. Referring to Figure 2, the top cell includes multiple top cells 10 connected in series. The arrow indicates a current flow direction in the top cell. The number of top cells included in the top cell can be determined according to the width of the top cell and the width Wp of the top cell of each top cell. The output voltage of the top cell can be determined by multiplying the opening voltage of each top cell by the number of top cells.

[0052] S120. Determine the target output voltage of the bottom battery based on the output voltage of the top battery.

[0053] The target output voltage of the bottom cell is the expected output voltage of the bottom cell, which is determined based on the output voltage of the top cell. Since the voltages of the top and bottom cells need to be matched to improve the photoelectric conversion efficiency of the solar cell module, the output voltage of the top cell can be set to be the same as the target output voltage of the bottom cell. However, due to subsequent packaging errors, the output voltage of the top cell may be different from the actual output voltage of the bottom cell. Therefore, it is necessary to adjust the error between the actual output voltage of the bottom cell and the output voltage of the top cell to be less than the preset value.

[0054] S130. Determine the width of each base cell of the base battery based on the target output voltage of the base battery, the width of the base battery, and the base cell opening voltage of each base cell included in the base battery; wherein, the base battery includes multiple base cells connected in series.

[0055] Among them, the width of the bottom cell is the total width of the bottom cells, the open voltage of each bottom cell is the open circuit voltage of a single bottom cell, and the width of each bottom cell is the width of a single cell in a single bottom cell.

[0056] Specifically, the width of the bottom battery can be set to W mm, the width of each sub-battery of the bottom battery can be Wc mm, and the opening voltage of each sub-battery can be Vc. The number of bottom batteries can be determined based on the target output voltage of the battery and the opening voltage Vc of each bottom battery. The number of bottom batteries can be obtained by dividing the target output voltage by the opening voltage Vc. The width Wc of each bottom battery can be determined by dividing the battery width W by the number of bottom batteries. The width Wc of each bottom battery can be determined by dividing the output voltage of the top battery by the opening voltage Vc of each bottom battery.

[0057] S140. Determine the actual output voltage of the bottom battery based on the width of each bottom battery, the width of the bottom battery, and the opening voltage of each bottom battery included in the bottom battery, so that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

[0058] The actual output voltage of the bottom battery is the actual output voltage of the bottom battery under the current bottom battery width. The number of bottom batteries can be determined by the bottom battery width W / the bottom battery width Wc of each bottom battery, and the number of bottom batteries is a positive integer. Then, by multiplying the bottom battery opening voltage Vc of each bottom battery by the number of bottom batteries, the actual output voltage of the bottom battery can be obtained as Vc * (W / Wc). Therefore, the actual output voltage of the bottom battery can be controlled by adjusting the bottom battery width of each bottom battery, so that the actual output voltage of the bottom battery is electrically similar to the output voltage of the top battery. The voltage difference is less than the preset value, thus matching the voltage of the bottom cell and the top cell. Because the voltage difference between the bottom cell and the top cell is not large, the photoelectric conversion efficiency will not decrease due to the large voltage difference between the bottom cell and the top cell, thereby improving the photoelectric conversion efficiency of the solar cell module. This avoids the need to use cell segments of 6 or 7 sizes or smaller to achieve a voltage value similar to the top cell in series, and avoids the loss of efficiency of the bottom cell during the cutting process, which would cause problems such as poor welding, microcracks and low yield of subsequent cell segments. The operation is simple and can reduce manufacturing costs.

[0059] The present invention provides a voltage matching method for a solar cell module, wherein the solar cell module includes a bottom cell and a top cell stacked sequentially; the voltage matching method includes: determining the output voltage of the top cell; determining the target output voltage of the bottom cell based on the output voltage of the top cell; determining the width of each bottom cell of the bottom cell based on the target output voltage of the bottom cell, the width of the bottom cell, and the open voltage of each bottom cell included in the bottom cell; wherein the bottom cell includes multiple bottom cells connected in series; determining the actual output voltage of the bottom cell based on the width of each bottom cell, the width of the bottom cell, and the open voltage of each bottom cell included in the bottom cell, such that the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell is less than a preset value. This invention can control the actual output voltage of the bottom cell by adjusting the width of each bottom cell, so that the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell is less than a preset value, thereby matching the voltages of the bottom and top cells. Since the voltage difference between the bottom and top cells is small, the photoelectric conversion efficiency will not decrease due to the large voltage difference between the bottom and top cells, thus improving the photoelectric conversion efficiency of the solar cell module.

[0060] Optionally, the default value is 10% of the top battery's output voltage.

[0061] Due to the precise selection of the encapsulated bottom and top cells, their voltages cannot be exactly the same. By adjusting the width of the bottom cell, the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell can be reduced to less than 10% of the output voltage of the top cell. This can maintain the stability of the solar cell module and improve its performance.

[0062] Optionally, the bottom and top batteries can have the same width.

[0063] Setting the bottom and top batteries to have the same width facilitates calculations and simplifies the calculation process.

[0064] Optionally, Figure 3 is a detailed flowchart of S130 in Figure 1. Referring to Figure 3, S130, determining the base cell width of each base cell in the base battery based on the target output voltage of the base battery, the battery width of the base battery, and the base cell opening voltage of each base cell included in the base battery, includes:

[0065] S131. Determine the number of base cells based on the target output voltage of the battery and the base cell opening voltage of each base cell included in the base cell.

[0066] Since the base cells are connected in series and each base cell has the same voltage, the number of base cells can be obtained by dividing the target output voltage by the base cell open voltage. The number of base cells is the number of base cells included in the target output voltage.

[0067] S132. Determine the base cell width of each base cell based on the number of base cells and the cell width of the base cells.

[0068] Specifically, the width of each base cell in the bottom cell is determined based on the cell width / number of base cells. Subsequently, the actual output voltage of the base cell is determined based on the obtained base cell width, so that the voltage difference between the actual output voltage of the base cell and the output voltage of the top cell is less than a preset value. Therefore, the voltage difference between the base cell and the top cell is not large, and the photoelectric conversion efficiency will not decrease due to the large voltage difference between the base cell and the top cell, thereby improving the photoelectric conversion efficiency of the solar cell module.

[0069] Optionally, the base battery includes a central region and a packaging region, the packaging region surrounds the central region, and the base battery is located in the central region; the base battery width of each base battery of the base battery is determined according to the number of base batteries and the battery width of the base battery, including: determining the base battery width according to the battery width of the base battery, the number of base batteries, and the preset size of the packaging region.

[0070] The width of the bottom battery is the total width of the bottom battery, which includes the total width of multiple bottom batteries and the width of the encapsulation area. The bottom battery adopts an internal series structure, which includes multiple bottom batteries connected in series. For example, a 10mm allowance is reserved around the encapsulation area, which is the size of the outer edge of the encapsulation area away from the center area towards the center area. Let the open voltage of a single bottom battery be Vc and the width of a single bottom battery be Wc millimeters. Since the bottom battery is located in the center area and the encapsulation area surrounds the center area, the total width of the bottom batteries in the center area is W-10*2. Therefore, the number of bottom batteries = (W-10*2) / Wc. Substituting the battery width, the number of bottom batteries, and the preset size of the encapsulation area, the width of the bottom battery Wc can be obtained. Subsequently, the actual output voltage of the bottom battery can be determined as Vc*(W-10*2) / Wc.

[0071] Optionally, Figure 4 is a flowchart of another voltage matching method for a solar cell module provided by an embodiment of the present invention. Referring to Figure 4, the voltage matching method includes:

[0072] S210. Determine the output voltage of the top battery based on the battery width of the top battery, the width of each sub-battery of the top battery, and the opening voltage of each sub-battery; wherein, the top battery includes multiple sub-batteries connected in series.

[0073] Among them, the width of the top battery is the total width of the top battery, the open voltage of each top sub-battery is the open circuit voltage of a single top battery, and the width of each top battery is the width of a single cell of a single top battery.

[0074] Specifically, Figure 5 is a schematic diagram of a solar cell module provided in an embodiment of the present invention. Referring to Figure 5, the arrow indicates that light enters from the top cell 10. If the bottom cell 20 and the top cell 10 are set to have the same width, the width of the top cell 10 can be set to W millimeters. The width of each top cell of the top cell 10 is Wp millimeters, and the opening voltage of each top cell is Vp. The number of top cells can be determined according to the width W of the top cell 10 / the width Wp of each top cell. The output voltage of the top cell 10 is obtained by multiplying the number of top cells by the opening voltage Vp.

[0075] S220. Determine the target output voltage of the bottom battery based on the output voltage of the top battery.

[0076] S230. Determine the width of each base cell of the base battery based on the target output voltage of the base battery, the width of the base battery, and the base cell opening voltage of each base cell included in the base battery; wherein, the base battery includes multiple base cells connected in series.

[0077] S240. Determine the actual output voltage of the bottom battery based on the width of each bottom battery, the battery width of the bottom battery, and the opening voltage of each bottom battery included in the bottom battery, so that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

[0078] S220-S240 are the same as S120-S140 and have the same beneficial effects.

[0079] Optionally, the top battery includes a central region and a packaging region, with the packaging region surrounding the central region, and all top sub-cells located in the central region; Figure 6 is a detailed flowchart of S210 in Figure 4. Referring to Figure 6, S210 determines the output voltage of the top battery based on the battery width of the top battery, the width of each top sub-cell of the top battery, and the opening voltage of each top sub-cell, including:

[0080] S211. Determine the number of top cells based on the width of the top cell, the preset size of the encapsulation area, and the width of the top cell.

[0081] The width of the top cell is the total width of the top cell, which includes the total width of multiple top cells and the width of the encapsulation area. The top cell adopts an internal series structure, which includes multiple top cells connected in series. For example, a 10mm allowance is reserved around the encapsulation area, which is the size of the outer edge of the encapsulation area away from the center area pointing towards the center area. Let the open voltage of a single top cell be Vp and the width of a single top cell be Wp millimeters. The laser etch lines are etched along the length of the cell, and the number of top cells = (W-10*2) / Wp.

[0082] S212. Determine the output voltage of the top battery based on the number of top batteries and the opening voltage of the top batteries.

[0083] The output voltage of the top battery is Vp*(W-10*2) / Wp; when the voltages of the bottom and top batteries are matched, Vp*(W-10*2) / Wp = Vc*(W-10*2) / Wc, i.e., Vp / Wp=Vc / Wc, means that for solar cell modules, voltage matching is the proportional relationship between the opening voltage and width of a single top cell and the opening voltage and width of a single bottom cell. Let's assume the top cell's opening voltage is 1.1V and its width is 5mm, while the bottom cell's opening voltage is 0.7V. Then the bottom cell width would be 0.7*5 / 1.1=3.18mm, approximately 3mm. The actual output voltage of the bottom cell is then obtained by multiplying the bottom cell width by the number of bottom cells and their opening voltage. This ensures that the actual output voltage of the bottom cell matches the output voltage of the top cell, making the voltage difference between them less than 10% of the top cell's output voltage. This maintains the stability of the solar cell module and improves its performance.

[0084] Optionally, Figure 7 is a schematic diagram of a solar cell module provided in an embodiment of the present invention. Referring to Figure 7, the bottom cell 20 is a copper indium gallium selenide (CIGS) cell; the CIGS cell includes a first substrate 21, a back electrode 22, a CIGS absorber layer 23, a buffer layer 24, and a third conductive layer 25 stacked sequentially; the top cell 10 is a perovskite cell; the perovskite cell includes a second substrate 11, a first conductive layer 12, a first carrier transport layer 13, a perovskite absorber layer 14, a second carrier transport layer 15, and a second conductive layer 16 stacked sequentially; the second substrate 11 is located on the side of the first conductive layer 12 away from the first substrate 21.

[0085] In this module, the top cell 10 and the bottom cell 20 are encapsulated together by an adhesive layer 30. The bottom cell 20 is a copper indium gallium selenide (CIGS) cell with a maximum efficiency of nearly 24%, while the top cell 10 is a perovskite cell with a maximum efficiency of 26.1%. Both the perovskite and CIGS cells are thin-film cells, encapsulated over the same large area. The perovskite cell acts as the incident light receiving layer, while the CIGS cell is used as the bottom encapsulation layer. Only one layer of adhesive film 30 is used in between, and the two types of cells complement each other in the encapsulation of the module. This solar cell module is a two-terminal tandem solar cell module using a CIGS cell as the bottom cell and a perovskite cell as the top cell. It maintains a stacked structure of two solar cell layers with different characteristics, improving the photoelectric conversion efficiency of the solar cell module. Furthermore, the fabrication method is simple, reducing manufacturing costs.

[0086] Based on the above embodiments, this invention provides a voltage matching device for a solar cell module, the solar cell module comprising: a bottom cell and a top cell stacked sequentially.

[0087] Figure 8 is a schematic diagram of a voltage matching device for a solar cell module provided in an embodiment of the present invention. Referring to Figure 8, the voltage matching device includes a first voltage determination module 310, a second voltage determination module 320, a width determination module 330, and a third voltage determination module 340.

[0088] The first voltage determination module 310 is used to determine the output voltage of the top battery;

[0089] The top cell can be a perovskite cell. Referring to Figure 2, the top cell includes multiple top cells 10 connected in series. The arrow indicates a current flow direction in the top cell. The first voltage determination module 310 can determine the number of top cells in the top cell based on the cell width of the top cell and the width Wp of the top cell of each top cell. The first voltage determination module 310 can then determine the output voltage of the top cell by multiplying the opening voltage of the top cell of each top cell by the number of top cells.

[0090] The second voltage determination module 320 is used to determine the target output voltage of the bottom battery based on the output voltage of the top battery;

[0091] The target output voltage of the bottom battery is the expected output voltage of the bottom battery determined based on the output voltage of the top battery. Because the voltages of the top battery and the bottom battery need to be matched to improve the photoelectric conversion efficiency of the solar cell module, the second voltage determination module 320 can set the output voltage of the top battery to be the same as the target output voltage of the bottom battery. However, due to subsequent packaging errors, the output voltage of the top battery may be different from the actual output voltage of the bottom battery. Therefore, it is necessary to adjust the error between the actual output voltage of the bottom battery and the output voltage of the top battery to be less than the preset value.

[0092] The width determination module 330 is used to determine the width of each base cell of the bottom battery based on the target output voltage of the bottom battery, the width of the bottom battery, and the base cell opening voltage of each base cell included in the bottom battery; wherein, the bottom battery includes multiple base cells connected in series with each other;

[0093] Among them, the width of the bottom cell is the total width of the bottom cells, the open voltage of each bottom cell is the open circuit voltage of a single bottom cell, and the width of each bottom cell is the width of a single cell in a single bottom cell.

[0094] Specifically, the width of the bottom battery can be set to W mm, the width of each sub-battery of the bottom battery can be Wc mm, and the opening voltage of each sub-battery can be Vc. The width determination module 330 can determine the number of bottom batteries based on the target output voltage of the battery and the opening voltage Vc of each sub-battery. The width determination module 330 can obtain the number of bottom batteries by dividing the target output voltage by the opening voltage Vc of the bottom battery. The width determination module 330 determines the width Wc of each bottom battery based on the battery width W / the number of bottom batteries. The output voltage of the top battery and the opening voltage Vc of each bottom battery are used to determine the width Wc of each bottom battery.

[0095] The third voltage determination module 340 is used to determine the actual output voltage of the bottom battery based on the bottom battery width of each bottom battery, the battery width of the bottom battery, and the bottom battery opening voltage of each bottom battery included in the bottom battery, so that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

[0096] The actual output voltage of the base battery is the actual output voltage of the base battery under the current base battery width. The third voltage determination module 340 can determine the number of base batteries by dividing the base battery width W by the base battery width Wc of each base battery. The number of base batteries is a positive integer. The third voltage determination module 340 then multiplies the base battery opening voltage Vc of each base battery by the number of base batteries to obtain the actual output voltage of the base battery = Vc * (W / Wc). Therefore, the actual output voltage of the base battery can be controlled by adjusting the base battery width of each base battery, so that the actual output voltage of the base battery is... The voltage difference between the bottom and top cells is less than a preset value, thus matching the voltage of the bottom and top cells. Because the voltage difference between the bottom and top cells is small, the photoelectric conversion efficiency will not decrease due to a large voltage difference between the bottom and top cells, thereby improving the photoelectric conversion efficiency of the solar cell module. This avoids the need to use cell segments of 6 or 7 sizes or smaller to achieve a voltage value similar to the top cell, and avoids the loss of efficiency in the bottom cell during the cutting process, which can lead to problems such as poor welding, microcracks and low yield in subsequent cell segmentation. The operation is simple and can reduce manufacturing costs.

[0097] This invention can control the actual output voltage of the bottom cell by adjusting the width of each bottom cell, so that the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell is less than a preset value, thereby matching the voltages of the bottom and top cells. Since the voltage difference between the bottom and top cells is small, the photoelectric conversion efficiency will not decrease due to the large voltage difference between the bottom and top cells, thus improving the photoelectric conversion efficiency of the solar cell module.

[0098] Optionally, the default value is 10% of the top battery's output voltage.

[0099] Due to the precise selection of the encapsulated bottom and top cells, their voltages cannot be exactly the same. By adjusting the width of the bottom cell, the voltage difference between the actual output voltage of the bottom cell and the output voltage of the top cell can be reduced to less than 10% of the output voltage of the top cell. This can maintain the stability of the solar cell module and improve its performance.

[0100] Optionally, the bottom and top batteries can have the same width.

[0101] Setting the bottom and top batteries to have the same width facilitates calculations and simplifies the calculation process.

[0102] Optionally, Figure 9 is a schematic diagram of the width determination module provided in an embodiment of the present invention. Referring to Figure 9, the width determination module 330 includes a quantity determination submodule 331 and a width determination submodule 332.

[0103] The quantity determination submodule 331 is used to determine the quantity of the base battery based on the target output voltage of the battery and the base battery opening voltage of each base battery included in the base battery;

[0104] Since the base batteries are connected in series and each base battery has the same voltage, the quantity determination submodule 331 can obtain the number of base batteries by dividing the target output voltage by the base battery open voltage. The number of base batteries included in the target output voltage is the number of base batteries.

[0105] The width determination submodule 332 is used to determine the base cell width of each base cell of the base battery based on the number of base cells and the cell width of the base battery.

[0106] The width determination submodule 332 determines the width of each base cell in the bottom battery based on the cell width divided by the number of base cells. Subsequently, the third voltage determination module 340 determines the actual output voltage of the base cell using the obtained base cell width. This ensures that the voltage difference between the actual output voltage of the base cell and the output voltage of the top cell is less than a preset value. Therefore, the voltage difference between the base and top cells is small, and the photoelectric conversion efficiency will not decrease due to a large voltage difference between the base and top cells, thereby improving the photoelectric conversion efficiency of the solar cell module.

[0107] Optionally, the bottom battery includes a central region and a packaging region, the packaging region surrounds the central region, and the bottom battery is located in the central region; Figure 10 is a schematic diagram of the width determination submodule provided in an embodiment of the present invention. Referring to Figure 10, the width determination submodule 332 includes a width determination unit 3321.

[0108] The width determination unit 3321 is used to determine the width of the base battery based on the battery width of the base battery, the number of base batteries, and the preset size of the packaging area.

[0109] The width of the bottom battery is the total width of the bottom battery, which includes the total width of multiple bottom batteries and the width of the encapsulation area. The bottom battery adopts an internal series structure, which includes multiple bottom batteries connected in series. For example, a 10mm reserved dimension is reserved around the encapsulation area, which is the dimension of the outer edge of the encapsulation area away from the center area pointing towards the center area. Let the voltage of a single bottom battery be Vc and the width of a single bottom battery be Wc millimeters. Since the bottom battery is located in the center area and the encapsulation area surrounds the center area, the total width of the bottom batteries in the center area is W-10*2. Therefore, the number of bottom batteries = (W-10*2) / Wc. The width determination unit 3321 substitutes the battery width of the bottom battery, the number of bottom batteries and the preset dimension of the encapsulation area to obtain the width Wc of the bottom battery. Subsequently, the third voltage determination module 340 can determine that the actual output voltage of the bottom battery is Vc*(W-10*2) / Wc.

[0110] Optionally, FIG11 is a schematic diagram of the first voltage determination module provided in an embodiment of the present invention. Referring to FIG11, the first voltage determination module 310 includes a first voltage determination submodule 311.

[0111] The first voltage determination submodule 311 is used to determine the output voltage of the top battery based on the battery width of the top battery, the top battery width of each top cell of the top battery, and the top battery opening voltage of each top cell; wherein, the top battery includes multiple top cells connected in series.

[0112] Among them, the width of the top battery is the total width of the top battery, the open voltage of each top sub-battery is the open circuit voltage of a single top battery, and the width of each top battery is the width of a single cell of a single top battery.

[0113] Specifically, referring to Figure 5, the arrow indicates that light enters from the top battery 10. If the bottom battery 20 and the top battery 10 have the same width, the width of the top battery 10 can be set to W mm; the width of each top cell of the top battery 10 is Wp mm, and the opening voltage of each top cell is Vp; the first voltage determination submodule 311 can determine the number of top cells based on the width W of the top battery 10 / the width Wp of each top cell, and the first voltage determination submodule 311 obtains the output voltage of the top battery 10 by multiplying the number of top cells by the opening voltage Vp.

[0114] Optionally, the top cell includes a central region and a packaging region, with the packaging region surrounding the central region, and all top cells located in the central region;

[0115] Figure 12 is a schematic diagram of the first voltage determination submodule provided in an embodiment of the present invention. Referring to Figure 12, the first voltage determination submodule 311 includes a quantity determination unit 3111 and a voltage determination unit 3112.

[0116] The quantity determination unit 3111 is used to determine the quantity of the top battery based on the battery width of the top battery, the preset size of the packaging area, and the width of the top battery.

[0117] The width of the top cell is the total width of the top cell, which includes the total width of multiple top cells and the width of the encapsulation area. The top cell adopts an internal series structure, which includes multiple top cells connected in series. For example, a 10mm allowance is reserved around the encapsulation area, which is the size of the outer edge of the encapsulation area away from the center area pointing towards the center area. Let the open voltage of a single top cell be Vp and the width of a single top cell be Wp millimeters. The laser etch lines are etched along the length of the cell, and the number of top cells = (W-10*2) / Wp.

[0118] The voltage determination unit 3112 is used to determine the output voltage of the top battery based on the number of top batteries and the opening voltage of the top batteries.

[0119] The output voltage of the top battery is Vp*(W-10*2) / Wp; when the voltages of the bottom and top batteries are matched, Vp*(W-10*2) / Wp = Vc*(W-10*2) / Wc, i.e., Vp / Wp=Vc / Wc, means that for solar cell modules, voltage matching is the proportional relationship between the opening voltage and width of a single top cell and the opening voltage and width of a single bottom cell. Let's assume the opening voltage of the top cell is 1.1V and its width is 5mm, while the opening voltage of the bottom cell is 0.7V. Then the width of the bottom cell would be 0.7*5 / 1.1=3.18mm, approximately 3mm. The subsequent third voltage determination module 340 obtains the actual output voltage of the bottom cell by multiplying the bottom cell width by the number of bottom cells and the bottom cell opening voltage. This ensures that the actual output voltage of the bottom cell matches the output voltage of the top cell, making the voltage difference between them less than 10% of the top cell's output voltage. This maintains the stability of the solar cell module and improves its performance.

[0120] Optionally, referring to Figure 7, the bottom cell 20 is a copper indium gallium selenide (CIGS) cell; the CIGS cell includes a first substrate 21, a back electrode 22, a CIGS absorber layer 23, a buffer layer 24, and a third conductive layer 25 stacked sequentially; the top cell 10 is a perovskite cell; the perovskite cell includes a second substrate 11, a first conductive layer 12, a first carrier transport layer 13, a perovskite absorber layer 14, a second carrier transport layer 15, and a second conductive layer 16 stacked sequentially; the second substrate 11 is located on the side of the first conductive layer 12 away from the first substrate 21.

[0121] In this module, the top cell 10 and the bottom cell 20 are encapsulated together by an adhesive layer 30. The bottom cell 20 is a copper indium gallium selenide (CIGS) cell with a maximum efficiency of nearly 24%, while the top cell 10 is a perovskite cell with a maximum efficiency of 26.1%. Both the perovskite and CIGS cells are thin-film cells, encapsulated over the same large area. The perovskite cell acts as the incident light receiving layer, while the CIGS cell is used as the bottom encapsulation layer. Only one layer of adhesive film 30 is used in between, and the two types of cells complement each other in the encapsulation of the module. This solar cell module is a two-terminal tandem solar cell module using a CIGS cell as the bottom cell and a perovskite cell as the top cell. It maintains a stacked structure of two solar cell layers with different characteristics, improving the photoelectric conversion efficiency of the solar cell module. Furthermore, the fabrication method is simple, reducing manufacturing costs.

[0122] Based on the above embodiments, this invention also provides a solar cell module formed using the voltage matching method and / or the voltage matching device described in any embodiment of this invention.

[0123] The solar cell module provided in this embodiment of the invention has the same beneficial effects as the voltage matching method and / or voltage matching device described in any embodiment of the invention.

[0124] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0125] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A voltage matching method for a solar cell module, characterized in that, The solar cell module includes: a bottom cell and a top cell stacked sequentially; the voltage matching method includes: Determine the output voltage of the top battery; Determine the target output voltage of the bottom battery based on the output voltage of the top battery; The base cell width of each base cell in the base battery is determined based on the target output voltage of the base battery, the battery width of the base battery, and the base cell opening voltage of each base cell included in the base battery; wherein, the base battery includes multiple base cells connected in series with each other; The actual output voltage of the bottom battery is determined based on the width of each bottom battery, the battery width of the bottom battery, and the opening voltage of each bottom battery included in the bottom battery, such that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

2. The voltage matching method according to claim 1, characterized in that, The preset value is 10% of the output voltage of the top battery.

3. The voltage matching method according to claim 1, characterized in that, The bottom battery and the top battery have the same width.

4. The voltage matching method according to claim 1, characterized in that, The step of determining the base cell width of each base cell in the base battery based on the target output voltage of the base battery, the battery width of the base battery, and the base cell opening voltage of each base cell included in the base battery includes: The number of base cells is determined based on the target output voltage of the battery and the base cell opening voltage of each base cell included in the base battery; The base cell width of each base cell in the base battery is determined based on the number of base cells and the cell width of the base cells.

5. The voltage matching method according to claim 4, characterized in that, The base battery includes a central region and a packaging region, the packaging region surrounding the central region, and the base battery located in the central region; The step of determining the base cell width of each base cell of the base battery based on the number of base cells and the cell width of the base battery includes: The width of the base battery is determined based on the width of the base battery, the number of base batteries, and the preset size of the packaging area.

6. The voltage matching method according to claim 1, characterized in that, Determining the output voltage of the top battery includes: The output voltage of the top battery is determined based on the battery width of the top battery, the top battery width of each top cell of the top battery, and the top battery opening voltage of each top cell; wherein, the top battery comprises multiple top cells connected in series.

7. The voltage matching method according to claim 6, characterized in that, The top battery includes a central region and a packaging region, the packaging region surrounds the central region, and the top sub-batteries are all located in the central region; The step of determining the output voltage of the top battery based on the battery width of the top battery, the top battery width of each sub-battery of the top battery, and the top battery opening voltage of each sub-battery includes: The number of top batteries is determined based on the width of the top battery, the preset size of the packaging area, and the width of the top sub-battery. The output voltage of the top battery is determined based on the number of top batteries and the opening voltage of the top batteries.

8. The voltage matching method according to claim 1, characterized in that: The bottom battery is a copper indium gallium selenide (CIGS) battery; the CIGS battery includes a first substrate, a back electrode, a CIGS absorption layer, a buffer layer and a third conductive layer stacked sequentially. The top cell is a perovskite cell; the perovskite cell includes a second substrate, a first conductive layer, a first carrier transport layer, a perovskite absorption layer, a second carrier transport layer and a second conductive layer stacked in sequence; the second substrate is located on the side of the first conductive layer away from the first substrate.

9. A voltage matching device for a solar cell module, characterized in that, The solar cell module includes: a bottom cell and a top cell stacked in sequence; The voltage matching device includes: The first voltage determination module is used to determine the output voltage of the top battery; The second voltage determination module is used to determine the target output voltage of the bottom battery based on the output voltage of the top battery; A width determination module is used to determine the width of each base cell of the bottom battery based on the target output voltage of the bottom battery, the battery width of the bottom battery, and the base cell opening voltage of each base cell included in the bottom battery; wherein, the bottom battery includes multiple base cells connected in series with each other; The third voltage determination module is used to determine the actual output voltage of the bottom battery based on the width of the bottom battery of each bottom battery, the battery width of the bottom battery, and the bottom battery opening voltage of each bottom battery included in the bottom battery, so that the voltage difference between the actual output voltage of the bottom battery and the output voltage of the top battery is less than a preset value.

10. A solar cell module, characterized in that, It is formed using the voltage matching method according to any one of claims 1-8 and / or the voltage matching device according to claim 9.

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