Determination method of circuit topological structure, laminated solar cell and manufacturing method of laminated solar cell

Abstract

The invention discloses a method for determining a circuit topological structure, a laminated solar cell and a manufacturing method thereof, and relates to the field of photovoltaic technology. The method for determining the circuit topological structure comprises the steps of determining a target output voltage range according to a characteristic output curve of a first solar cell, and determining a target circuit topological structure of a sub-cell of a second solar cell according to the target output voltage range, so that the optimal output voltage of the second solar cell is within the target output voltage range. According to the method for determining the circuit topological structure provided by the embodiment of the invention, the target circuit topological structure of the sub-cell of the second solar cell is determined according to the target output voltage range, so that the power generation output characteristic can be better matched, and the voltage of the second solar cell is enabled to be in a better voltage range; and higher photoelectric conversion and power output are realized.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a method for determining a circuit topology structure, a stacked solar cell and a method for manufacturing the same. Background Art

[0002] The stacked solar cell utilizes the spectrum separately through two or more bandgap optoelectronic semiconductor light-absorbing layers, thereby reducing the energy loss of photons generating photogenerated electrons / photogenerated excitons through the photovoltaic phenomenon, thereby improving the photoelectric conversion efficiency and increasing the system efficiency. In general, the spectrum difference AM1.5 has water vapor absorption peaks near 760nm, 900nm, and 1150nm, so the light intensity here will be reduced. In addition, the spectrum that finally reaches the ground will be affected by different times of the day, different solar radiation angles, air quality, atmospheric humidity, etc. In addition, the spectrum reaching the semiconductor light-absorbing layer will also change for sunlight directly entering the cell and for sunlight entering the cell at an angle.

[0003] Existing stacked cells are mainly two-terminal stacked cells, which stack the top cell and the bottom cell in series by sharing a conductive electrode. Series cells are very sensitive to spectral changes. When the outdoor spectrum changes slightly, or even when the incident angle of sunlight changes, it will cause series current mismatch, thereby greatly reducing the power generation output. Summary of the invention

[0004] The purpose of the present application includes providing a method for determining a circuit topology structure, a stacked solar cell and a method for manufacturing the same, so as to improve the problem that the existing stacked solar cell is prone to series current mismatch resulting in low power generation efficiency.

[0005] The embodiments of the present application can be implemented as follows:

[0006] In a first aspect, the present application provides a method for determining a circuit topology structure, which is used to determine a target circuit topology structure of a solar cell in a stacked solar cell, wherein the stacked solar cell includes a first solar cell and a second solar cell, wherein the second solar cell includes a plurality of sub-cells, and the method for determining the circuit topology structure includes:

[0007] Determining a characteristic output curve of the first solar cell, the characteristic output curve representing a mapping relationship between an output voltage and an output power of the first solar cell under set operating conditions;

[0008] determining a target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under set operating conditions, wherein the output voltage corresponding to the maximum output power of the first solar cell under set operating conditions is within the target output voltage range;

[0009] At least according to the target output voltage range, a target circuit topology of the subcell of the second solar cell is determined so that the optimal output voltage of the second solar cell is within the target output voltage range, wherein the optimal output voltage of the second solar cell is the output voltage corresponding to the maximum output power of the second solar cell.

[0010] In an optional embodiment, the step of determining the target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under set operating conditions includes:

[0011] Determining the maximum output power of the first solar cell under set operating conditions according to the characteristic output curve;

[0012] Determine the allowable loss power, and use the maximum output power to subtract the allowable loss power to obtain the allowable maximum deviation output power, wherein the allowable loss power is a preset value or a preset ratio of the maximum output power, and the preset ratio has a value range of (0,0.4];

[0013] According to the characteristic output curve and the maximum allowable deviation output power, the first target voltage value and the second target voltage value corresponding to the maximum allowable deviation output power are determined, the first target voltage value is less than the second target voltage value, the first target voltage value is determined as the lower limit value of the target output voltage range, and the second target voltage value is determined as the upper limit value of the target output voltage range.

[0014] In an optional implementation, the preset ratio has a value range of (0, 0.2].

[0015] In an optional embodiment, the step of determining the target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under set operating conditions includes:

[0016] Determining the maximum output power of the first solar cell under set operating conditions according to the characteristic output curve;

[0017] Determine the allowable loss power, and subtract the allowable loss power from the maximum output power to obtain the allowable maximum deviation output power, wherein the allowable loss power is a preset value or a preset ratio of the maximum output power, and the preset ratio has a value range of (0,0.4];

[0018] Determine, according to the characteristic output curve and the maximum allowable deviation output power, a first initial voltage value and a second initial voltage value corresponding to the maximum allowable deviation output power, wherein the first initial voltage value is less than the second initial voltage value;

[0019] Determine a first voltage deviation coefficient and a second voltage deviation coefficient, determine the product of the first initial voltage value and the first voltage deviation coefficient as a third target voltage value, determine the product of the second initial voltage value and the second voltage deviation coefficient as a fourth target voltage value, determine the third target voltage value as a lower limit value of the target output voltage range, and determine the fourth target voltage value as an upper limit value of the target output voltage range.

[0020] In an optional embodiment, the step of determining a target circuit topology of a sub-cell of the second solar cell according to at least the target output voltage range comprises:

[0021] Determine an optimal output voltage of a sub-cell of the second solar cell, where the optimal output voltage of the sub-cell is an output voltage corresponding to a maximum output power of the sub-cell;

[0022] Determining a target number of series-connected subcells and a target number of parallel-connected subcells of the second solar cell according to an optimal output voltage and a target output voltage range of the subcells of the second solar cell;

[0023] A target circuit topology of the subcells of the second solar cell is determined according to a target number of subcells connected in series and a target number of subcells connected in parallel of the second solar cell, wherein the number of subcells connected in series of the second solar cell in the target circuit topology satisfies the target number of subcells connected in series, and the number of subcells connected in parallel of the second solar cell in the target circuit topology satisfies the target number of subcells connected in parallel.

[0024] In an optional embodiment, the tandem solar cell includes a bottom cell, a top cell, and at least one middle cell stacked between the top cell and the bottom cell;

[0025] One of the first solar cell and the second solar cell is a top cell, and the other is a middle cell adjacent to the top cell; or, the first solar cell and the second solar cell are two adjacent middle cells; or, one of the first solar cell and the second solar cell is a bottom cell, and the other is a middle cell adjacent to the bottom cell.

[0026] In an optional embodiment, the step of determining a characteristic output curve of the first solar cell includes:

[0027] Determining a set operating condition, the set operating condition at least including a spectrum value of a target environment and a target operating temperature of the first solar cell;

[0028] A mapping relationship between an output voltage and an output power of the first solar cell under set operating conditions is determined to obtain a characteristic output curve of the first solar cell.

[0029] In a second aspect, the present application provides a method for manufacturing a stacked solar cell, comprising:

[0030] providing a first solar cell;

[0031] Connecting the plurality of sub-cells according to a target circuit topology structure to obtain a second solar cell, wherein the target circuit topology structure is determined according to the method for determining the circuit topology structure of any one of the aforementioned embodiments;

[0032] The first solar cell and the second solar cell are stacked to obtain a stacked solar cell.

[0033] In an optional embodiment, the first solar cell is a perovskite cell, and the second solar cell is a crystalline silicon cell.

[0034] In a third aspect, the present application provides a stacked solar cell manufactured by the manufacturing method of the stacked solar cell in the aforementioned embodiment.

[0035] The beneficial effects of the circuit topology determination method, stacked solar cell and manufacturing method thereof provided in the embodiments of the present application include:

[0036] The circuit topology determination method provided in the embodiment of the present application includes determining the characteristic output curve of the first solar cell, wherein the characteristic output curve represents the mapping relationship between the output voltage and the output power of the first solar cell under set operating conditions; determining the target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under set operating conditions, wherein the output voltage corresponding to the maximum output power of the first solar cell under set operating conditions is within the target output voltage range; determining the target circuit topology of the sub-cell of the second solar cell at least according to the target output voltage range, so that the optimal output voltage of the second solar cell is within the target output voltage range, wherein the optimal output voltage of the second solar cell is the output voltage corresponding to the maximum output power of the second solar cell. The circuit topology determination method provided in the embodiment of the present application determines the target output voltage range according to the characteristic output curve of the first solar cell, and the output power range corresponding to the target output voltage range is at a higher level. Determining the target circuit topology of the sub-cell of the second solar cell according to the target output voltage range can better match the power generation output characteristics, so that the voltage of the second solar cell is within a better voltage range, and achieves higher photoelectric conversion and power output. Moreover, by coupling and adapting the second solar cell to the first solar cell, a two-terminal stacked cell without an intermediate charge transfer layer can be formed, which can realize double-junction power generation and convergence, greatly achieving the goal of reducing costs and increasing efficiency, and improving the problem of low power generation efficiency caused by series current mismatch in existing stacked solar cells.

[0037] The manufacturing method of the stacked solar cell provided in the embodiment of the present application includes using the above-mentioned circuit topology determination method to determine the circuit topology structure of the second solar cell; the stacked solar cell provided in the embodiment of the present application is manufactured by the above-mentioned manufacturing method, and therefore has the advantage of high power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram of a first solar cell and a second solar cell in a stacked solar cell in an embodiment of the present application;

[0040] Figure 2 This is a flow chart of a method for determining a circuit topology structure in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of a characteristic output curve of a perovskite solar cell in one embodiment of the present application;

[0042] Figure 4 This is a flow chart of a method for manufacturing a stacked solar cell in one embodiment of the present application.

[0043] Icon: 100 - first solar cell; 110 - first transmission bus layer; 120 - light absorption layer; 130 - second transmission bus layer; 140 - transparent substrate; 200 - second solar cell; 210 - passivation bus layer; 220 - photoelectric semiconductor layer; 230 - back field bus layer; 240 - bus structure. DETAILED DESCRIPTION

[0044] In the stacked solar cells in the related art, the series cells are very sensitive to spectral changes. When the outdoor spectrum changes slightly, or even when the incident angle of sunlight changes, it will cause series current mismatch, thereby greatly reducing the power generation output. In addition, the conventional series-connected two-terminal stacked cells mainly have current mismatch, which causes the high-current cells to have to "reduce current" operation, and therefore will greatly deviate from their respective maximum power output points. In order to solve the problem that the existing stacked solar cells are prone to series current mismatch and lead to low power generation efficiency, the embodiments of the present application provide a method for determining a circuit topology structure, by determining the target output voltage range according to the working characteristic curve of the first solar cell, and then determining the circuit topology structure of the sub-cell of the second solar cell according to the target output voltage range, so that the second solar cell is coupled and adapted to the first solar cell, and is not prone to current mismatch problems, thereby improving power generation efficiency. The embodiments of the present application also provide a stacked solar cell and a preparation method thereof.

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0046] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0047] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0048] In the description of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, it is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0049] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0050] It should be noted that, in the absence of conflict, the features in the embodiments of the present application may be combined with each other.

[0051] Figure 1 FIG. 1 is a schematic diagram of a first solar cell 100 and a second solar cell 200 in a stacked solar cell in an embodiment of the present application. Figure 1 As shown, the stacked solar cell provided in the embodiment of the present application includes a first solar cell 100 and a second solar cell 200 adjacent to each other. For the convenience of display, Figure 1 In the figure, the first solar cell 100 and the second solar cell 200 are shown separately.

[0052] It should be understood that the stacked solar cell may include at least two solar cells arranged in a stacked manner. For a two-junction cell, the stacked solar cell includes a top cell and a bottom cell. Among them, the top cell is the first cell to receive incident sunlight, a portion of the sunlight is absorbed by the top cell, and a portion passes through the top cell and then enters the bottom cell. In an optional embodiment, the stacked solar cell may also include at least one intermediate cell stacked between the top cell and the bottom cell. The first solar cell 100 and the second solar cell 200 are two adjacent cells in the stacked solar cell. For example, one of the first solar cell 100 and the second solar cell 200 is a top cell, and the other is an intermediate cell adjacent to the top cell; or, the first solar cell 100 and the second solar cell 200 are two adjacent intermediate cells; or, one of the first solar cell 100 and the second solar cell 200 is a bottom cell, and the other is an intermediate cell adjacent to the bottom cell.

[0053] Optionally, the first solar cell 100 is a perovskite cell, and the second solar cell 200 is a crystalline silicon cell; further, the first solar cell 100 is a top cell, and the second solar cell 200 is a bottom cell. The crystalline silicon cell can be a back passivated emitter rear cell (Passivated Emitter Rear Cell, referred to as Perc), a tunnel oxide passivated contact solar cell (Tunnel Oxide Passivated Contact solar cell, referred to as Topcon), a high-efficiency crystalline silicon cell (Heterojunction with Intrinsic Thinfilm, referred to as HIT or HJT), or an interdigitated back contact cell (Interdigitated back contact cell, referred to as IBC).

[0054] like Figure 1As shown, the first solar cell 100 includes a first transmission bus layer 110, a light absorbing layer 120, a second transmission bus layer 130 and a transparent substrate 140 which are stacked in sequence. A first groove is engraved on the second transmission bus layer 130, a second groove is engraved on the light absorbing layer 120, and a third groove is engraved on the first transmission bus layer 110 and the light absorbing layer 120. The third groove divides two subcells of the first solar cell 100, and the second groove is filled with the material of the first transmission bus layer 110, so that the first transmission bus layer 110 of one subcell is electrically connected to the second transmission bus layer 130 of the adjacent subcell, and the first groove is filled with the material of the light absorbing layer 120, and the first groove separates the second transmission bus layers 130 corresponding to the two adjacent subcells. The light absorbing layer 120 is the location where photovoltaics occur, and the material of the transparent substrate 140 can be selected as glass, such as fluorine-doped tin oxide (FTO) coated glass and / or indium-doped tin oxide (ITO) coated glass. The first transmission bus layer 110 may be an N-type transmission bus, and the second transmission bus layer 130 may be a P-type transmission bus. The first transmission bus layer 110 and the second transmission bus layer 130 are two bus terminals of the first solar cell 100. The thickness of the first transmission bus layer 110 and the second transmission bus layer 130 may be 50 to 200 nm, and the thickness of the light absorption layer 120 may be 300 to 800 nm.

[0055] Taking the second solar cell 200 as a back field crystalline silicon solar cell as an example, the second solar cell 200 includes a plurality of sub-cells, and each sub-cell of the second solar cell 200 includes a passivation bus layer 210, a photoelectric semiconductor layer 220, and a back field bus layer 230 stacked in sequence. The photoelectric semiconductor layer 220 can form a pn junction, and the passivation bus layer 210 can include Si 3 N 4 The back field bus layer 230 is a composite structure of a back surface field layer and a back electrode bus layer, wherein the materials of the back surface field layer and the back electrode bus layer can both be Al, that is, the back field bus layer 230 is a composite structure of an Al back field layer and an Al conductive layer. In the second solar cell 200, the subcells can be connected in series or in parallel through the bus structure 240 ( Figure 1 The sub-cells are shown in series in FIG. 1 ), and the busbar structure 240 can be a solder strip or a conductive adhesive. It should be understood that Figure 1 The second solar cell 200 shown in the figure is a back-field crystalline silicon solar cell as an example. In other embodiments, the second solar cell 200 may also be a HJT heterojunction cell or other structures, and its various layer structures should be adjusted as needed.

[0056] Figure 2Flow chart of a method for determining a circuit topology structure in an embodiment of the present application. The method for determining a circuit topology structure provided in an embodiment of the present application is used to determine a target circuit topology structure of a solar cell in a stacked solar cell, and is specifically used to determine a target circuit topology structure of a sub-cell of a second solar cell 200 based on a first solar cell 100. Figure 2 As shown, the method for determining the circuit topology structure provided in the embodiment of the present application includes:

[0057] Step S100 , determining a characteristic output curve of the first solar cell 100 , where the characteristic output curve represents a mapping relationship between an output voltage and an output power of the first solar cell 100 under set operating conditions.

[0058] Figure 3 Schematic diagram of characteristic output curve of perovskite solar cell in one embodiment of the present application. Figure 3 As shown in the figure, A is the PV curve and B is the IV curve. Taking the PV curve as an example, when the first solar cell 100 is a titanite solar cell, the characteristic output curve of the first solar cell 100 is Figure 3 The PV curve diagram (i.e. the relationship between power and voltage) is shown.

[0059] The step of determining the characteristic output curve of the first solar cell 100 in step S100 may specifically include the following steps:

[0060] Step S101, determining a set operating condition, where the set operating condition at least includes a spectrum value of a target environment and a target operating temperature of the first solar cell 100;

[0061] Step S102 : determining a mapping relationship between an output voltage and an output power of the first solar cell 100 under set operating conditions to obtain a characteristic output curve of the first solar cell 100 .

[0062] Optionally, the target environment is the working environment in which the first solar cell 100 needs to be located. In this way, the influence of climate reasons on the spectral curve of the battery can be taken into account, and an accurate spectral curve of the solar cell in the target environment can be obtained. In addition, the first solar cell 100 can be one of the top battery, the bottom battery or the middle battery. When the first solar cell 100 is not the top battery, the battery located above the first solar cell 100 will have a filtering effect. After the filtering effect of the battery above the first solar cell 100, the light intensity reaching the first solar cell 100 will be weakened, and the spectral curve of the first solar cell 100 will also change accordingly. Therefore, the above steps S101 to S102 also take into account the influence of this scenario on the spectral curve of the first solar cell 100.

[0063] Because climate factors affect the spectrum curve of the battery, the traditional two-terminal series connection is more difficult to manufacture, the cost is high, and the current is easily mismatched, resulting in low efficiency and low power generation. The above embodiment better matches the power generation output characteristics (see subsequent steps S200 and S300) according to the power generation characteristic curve of the first solar cell 100, so that it is within a better voltage range. In addition, components in different regions do need to be based on the actual spectrum and climate characteristics (such as strong winds, rainfall, cold air, etc., which will affect the temperature of the components when generating electricity / outputting), so an optimal voltage adjustment and adaptation of the changes are required to achieve higher photoelectric conversion and power output.

[0064] Step S200, determining a target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell 100 under set operating conditions, wherein the output voltage corresponding to the maximum output power of the first solar cell 100 under set operating conditions is within the target output voltage range.

[0065] It can be seen that the target output voltage range determined in step S200 is an output voltage range with higher energy efficiency, and the output power corresponding to it is a larger output power range of the first solar cell 100 (because the output voltage corresponding to the maximum output power is within the target output voltage range). The target output voltage range can be a range that fluctuates up and down based on the output voltage corresponding to the maximum output power of the first solar cell 100 under set operating conditions.

[0066] In an optional embodiment, the step of determining the target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell 100 under set operating conditions in step S200 specifically includes:

[0067] Step S201, determining the maximum output power of the first solar cell 100 under set operating conditions according to the characteristic output curve;

[0068] Step S202, determining the allowable power loss, subtracting the allowable power loss from the maximum output power to obtain the allowable maximum deviation output power, wherein the allowable power loss is a preset value or a preset ratio of the maximum output power, and the preset ratio has a value range of (0,0.4];

[0069] Step S203, based on the characteristic output curve and the maximum allowable deviation output power, determine the first target voltage value and the second target voltage value corresponding to the maximum allowable deviation output power, the first target voltage value is less than the second target voltage value, the first target voltage value is determined as the lower limit value of the target output voltage range, and the second target voltage value is determined as the upper limit value of the target output voltage range.

[0070] Combination Figure 3 As shown, in the above steps S201 to S203, the maximum output power P max is a point value corresponding to the optimal output voltage V max The allowable power loss △P represents the power that can be lost when matching the voltage, P max -△P is the maximum allowable deviation output power. Among them, △P can be a preset value or the maximum output power P max The preset ratio, the value range of the preset ratio is (0,0.4]. Figure 3 The η in the formula is the maximum allowable deviation output power coefficient, which is equal to 1 minus the preset ratio. Since η is less than 1, ηP max Less than P max On the PV curve, the maximum deviation output power corresponds to two horizontal axis values, and thus corresponds to two output voltage values, namely the first target voltage value V a and the second target voltage value V b . In this embodiment, the preset ratio or the maximum allowable deviation output power coefficient η can be an empirical value obtained based on historical data; further optionally, the preset ratio has a value range of (0, 0.2], and the corresponding maximum allowable deviation output power coefficient η has a value range of [0.8, 1]; further optionally, the preset ratio has a value range of [0.01, 0.1], and the corresponding maximum allowable deviation output power coefficient η has a value range of [0.9, 0.99], for example, η is 0.95. In this way, the output power corresponding to the target output voltage range can be controlled within an output range that meets the requirements.

[0071] Taking the first solar cell 100 as a perovskite solar top cell, the second solar cell 200 as a crystalline silicon bottom cell, and the perovskite solar top cell and the crystalline silicon bottom cell stacked to obtain a two-end stacked solar cell as an example, the target output voltage range of the second solar cell 200 is determined by the characteristic output curve (PV curve) of the first solar cell 100 and the maximum allowable deviation output power, thereby ensuring that the stacked solar cell can maintain the best output state under the simplest structure to achieve the optimal power generation efficiency.

[0072] In addition to the above methods, other methods can be used to determine the target output voltage range. For example, when obtaining the maximum output power P max The corresponding optimal output voltage V max After that, the optimal output voltage V max Add or subtract a floating value based on the optimal output voltage V max The lower limit of the target output voltage range is obtained by multiplying the first voltage correction coefficient less than 1. maxThe upper limit of the target output voltage range is obtained by multiplying the first voltage correction coefficient by a second voltage correction coefficient greater than 1. The above floating value and coefficient can be empirical values ​​obtained based on historical data; optionally, the value range of the first voltage correction coefficient is [0.8, 1), and the value range of the second voltage correction coefficient is (1, 1.25].

[0073] In an optional embodiment, the step of determining the target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell 100 under set operating conditions in step S200 specifically includes:

[0074] Step S211, determining the maximum output power of the first solar cell 100 under set operating conditions according to the characteristic output curve;

[0075] Step S212, determining the allowable power loss, using the maximum output power minus the allowable power loss to obtain the allowable maximum deviation output power, wherein the allowable power loss is a preset value or a preset ratio of the maximum output power, and the preset ratio has a value range of (0,0.4];

[0076] Step S213, determining a first initial voltage value and a second initial voltage value corresponding to the maximum allowable deviation output power according to the characteristic output curve and the maximum allowable deviation output power, wherein the first initial voltage value is smaller than the second initial voltage value;

[0077] Step S214, determine the first voltage deviation coefficient and the second voltage deviation coefficient, determine the product of the first initial voltage value and the first voltage deviation coefficient as the third target voltage value, determine the product of the second initial voltage value and the second voltage deviation coefficient as the fourth target voltage value, determine the third target voltage value as the lower limit value of the target output voltage range, and determine the fourth target voltage value as the upper limit value of the target output voltage range.

[0078] Wherein, when the actual voltage value of the first solar cell 100 is greater than or equal to the third target voltage value and less than or equal to the fourth target voltage value, the actual output power of the first solar cell 100 is greater than or equal to the maximum allowable deviation output power. Through the above steps S211 to S214, the actual error of the voltage can be taken into account, and the voltage range can be determined based on actual conditions instead of being limited to between the first initial voltage value and the second initial voltage value. The values ​​of the first voltage deviation coefficient and the second voltage deviation coefficient can be set based on historical data and actual conditions.

[0079] Step S300, determining a target circuit topology of a sub-cell of the second solar cell 200 at least according to a target output voltage range, so that an optimal output voltage of the second solar cell 200 is within the target output voltage range, wherein the optimal output voltage of the second solar cell 200 is an output voltage corresponding to when the output power of the second solar cell 200 is maximum.

[0080] Optionally, the first solar cell 100 and the second solar cell 200 are not of the same type, and there is a difference between the band gap of the first solar cell 100 and the band gap of the second solar cell 200, so that the spectrum can be utilized in stages, thereby improving the utilization rate of light energy.

[0081] Furthermore, step S300 specifically includes:

[0082] Step S310, determining the optimal output voltage of the sub-cell of the second solar cell 200, where the optimal output voltage of the sub-cell is the output voltage corresponding to the maximum output power of the sub-cell;

[0083] Step S320, determining a target number of sub-cells connected in series and a target number of sub-cells connected in parallel of the second solar cell 200 according to the optimal output voltage and the target output voltage range of the sub-cells of the second solar cell 200;

[0084] Step S330, determining a target circuit topology of the sub-cells of the second solar cell 200 according to a target number of sub-cells connected in series and a target number of sub-cells connected in parallel of the second solar cell 200, wherein the number of sub-cells connected in series of the second solar cell 200 in the target circuit topology meets the target number of sub-cells connected in series, and the number of sub-cells connected in parallel of the second solar cell 200 in the target circuit topology meets the target number of sub-cells connected in parallel.

[0085] In this way, the difference in the current convergence of the sub-cells of the second solar cell 200 in the series connection state can be taken into account, thereby improving the accuracy of the determination method.

[0086] In this embodiment, one of the first solar cell 100 and the second solar cell 200 is a top cell, and the other is a middle cell adjacent to the top cell; or, the first solar cell 100 and the second solar cell 200 are two adjacent middle cells; or, one of the first solar cell 100 and the second solar cell 200 is a bottom cell, and the other is a middle cell adjacent to the bottom cell; or, one of the first solar cell 100 and the second solar cell 200 is a bottom cell, and the other is a top cell adjacent to the bottom cell. Therefore, through the above-mentioned method for determining the circuit topology structure, the series-parallel connection mode of the bottom cell can be determined according to the top cell, and the series-parallel connection mode of the top cell can also be determined according to the bottom cell, which can also make the solar cell have better self-adaptability. In addition, the stacked cell has a higher photoelectric conversion efficiency than the single-junction cell. The stacked solar cell has three or more layers of cells, and the specific setting principle is the same as that of two layers.

[0087] By effectively analyzing the PV curve (power-voltage characteristic output curve) or IV curve (current-voltage characteristic output curve) of the top cell and the bottom cell, the voltage of the battery module can be effectively matched according to the voltage change under the effective output power of the battery, thereby broadening the output characteristics under different working conditions and maximizing the adaptation characteristics to the wide segregation spectrum state, so as to achieve more effective terminal degeneration, reduce the convergence system of the component, and ensure the power generation efficiency of two-junction cells or more-junction cells, which is more conducive to commercial photovoltaic power generation applications.

[0088] The following is an explanation of the method for determining the circuit topology structure of the present application:

[0089] The first solar cell 100 is a perovskite solar cell, the second solar cell 200 is a crystalline silicon bottom cell, and the perovskite solar cell and the crystalline silicon bottom cell are stacked to obtain a two-terminal stacked solar cell. Figure 3 As shown, the maximum output power P max Corresponding to a V max , set the maximum allowable deviation output power coefficient to η, then the maximum allowable deviation output power is ηP max , then ηP max There are two corresponding output points, corresponding to V a (first target voltage value) and V b (second target voltage value), set V a ≤V m-bottom-n ≤V b Theoretically V m-bottom-n The value is equal to N×V m-bottom , where V m-bottomis the optimal output voltage of a sub-cell in the second solar cell 200, and N is the number of sub-cells connected in series in the second solar cell 200. However, in actual situations, since the series resistance and confluence loss introduced in the series structure are different from those of a single cell, V m-bottom-n V after connecting N sub-batteries in series m-bottom Therefore, in this embodiment, V m-bottom-n It is represented as the maximum output power voltage of the second solar cell 200 under the working condition of filtering light.

[0090] Since different batteries have different fill factors FF and different IV output graphs, for η×P max The corresponding variation ranges of the first target voltage value and the second target voltage value are also different.

[0091] It should be understood that the first solar cell 100 will have different characteristic output curves under variable operating conditions, for example, different characteristic output curves will be present at different times in a certain area. Therefore, the set operating conditions in step S100 of the embodiment of the present application should be selected according to the actual application situation. In an optional embodiment, a plurality of different set operating conditions can be determined according to a plurality of different moments i, and then the maximum output power Pmax,i and the corresponding optimal output voltage Vmax,i at each moment i can be determined. Through step S200, a plurality of target output voltage ranges for different moments i can be obtained, and then the final target output voltage range can be obtained by averaging or weighted averaging, which is used to determine the target circuit topology of the second solar cell 200.

[0092] Figure 4 Flow chart of a method for manufacturing a stacked solar cell in one embodiment of the present application. Figure 4 As shown, the method for manufacturing a stacked solar cell provided in the embodiment of the present application includes:

[0093] Step S10, providing a first solar cell 100;

[0094] Step S20, connecting the plurality of sub-cells according to the target circuit topology to obtain a second solar cell 200;

[0095] Step S30 , stacking the first solar cell 100 and the second solar cell 200 to obtain a stacked solar cell.

[0096] The target circuit topology structure in step S20 is determined by the circuit topology structure determination method provided in the above embodiment of the present application. Optionally, the first solar cell 100 is a perovskite cell, and the second solar cell 200 is a crystalline silicon cell.

[0097] The manufacturing method of the stacked solar cell provided in the embodiment of the present application better matches the power generation output characteristics according to the output characteristic curves of the first solar cell 100 and the second solar cell 200, so that it can achieve higher photoelectric conversion and power output within a better voltage range, and through the coupling adaptation of the second solar cell 200 to the power output curve of the first solar cell 100, a two-terminal stacked cell without an intermediate charge transfer layer is formed, which can realize double-junction power generation and one-way convergence, greatly achieving the purpose of reducing costs and increasing efficiency, and improving the problem of low power generation efficiency caused by series current mismatch in existing stacked solar cells.

[0098] In the embodiment of the present application, the back field bus layer 230 and the passivation bus layer 210 of the subcell of the second solar cell 200 are two bus terminals of the subcell. Optionally, the step of connecting the plurality of subcells in the plurality of second solar cells 200 in parallel includes: providing a plurality of subcells arranged at intervals; connecting the anodes of the respective subcells by using a first welding ribbon, and connecting the cathodes of the respective subcells by using a second welding ribbon, so as to obtain the plurality of subcells connected in parallel.

[0099] In the case where the first solar cell 100 is a top cell, the spectrum of sunlight undergoes a significant change after passing through the first solar cell 100. The most important thing is that the short-wave light is absorbed by the top cell, leaving long-wave photons. This part of the photons will also generate electricity when irradiated on the second solar cell 200. In addition, there are two better advantages: first, there are fewer high-energy photons. According to the nature of the photovoltaic phenomenon, for photons that are higher than the band gap of crystalline silicon, the excess energy will generate heat in the form of phonons, thereby wasting the energy of the photons and reducing the conversion efficiency of light to electricity; on the other hand, in the case where the second solar cell 200 is a crystalline silicon cell, since the temperature coefficient of crystalline silicon is negative, the heat generated by high-energy photons is reduced, thereby avoiding excessive temperature rise of the second solar cell 200, and the photoelectric conversion efficiency of the second solar cell 200 can be guaranteed.

[0100] The tandem solar cell provided in the embodiment of the present application can be manufactured by the above-mentioned manufacturing method of the tandem solar cell. The tandem solar cell of the present application is specifically introduced through embodiments 1 to 4 below.

[0101] Example 1

[0102] The stacked solar cell includes a top cell and a bottom cell, wherein the first solar cell 100 is the top cell and the second solar cell 200 is the bottom cell. The MaPbI based 3The first perovskite solar cell 100 has a characteristic working curve of PV curve, an open circuit voltage of 100V, a maximum power point voltage of 86V, and a fill factor of 78%. The maximum deviation output power coefficient is determined to be 0.95, and on this basis, the first target voltage value V a is 83V, the second target voltage value V b The sub-cell of the second solar cell 200 is a Perc cell, and the open circuit voltage of the sub-cell of the second solar cell 200 is about 0.70V, and the optimal output voltage is 0.61V.

[0103] Because the temperature coefficient of the first solar cell 100 is inconsistent with the temperature coefficient of the second solar cell 200, and after the stacking arrangement, the equilibrium temperature of the first solar cell 100 and the second solar cell 200 under specific illumination will be different from the temperature of the first solar cell 100 and the second solar cell 200 under illumination; at the same time, under actual working conditions, since high-energy particles have been absorbed, the additional energy loss (phonon) at the narrow-bandgap second solar cell 200 will be reduced, so the working temperature will be reduced, and the temperature reduction in the working state is beneficial to the efficiency gain of the second solar cell 200. Therefore, the temperature difference factor of the second solar cell 200 under the service condition is considered in this embodiment compared with the temperature under AM1.5G illumination.

[0104] In addition, in this embodiment, after the first solar cell 100 absorbs the short-wave photons, the remaining low-energy photons are incident on the second solar cell 200, which is equivalent to a decrease in light intensity. According to the detailed balance theory of photovoltaic semiconductors and the composite equivalent model, it can be calculated that Among them, C is the ratio of light intensity to STC light intensity. Generally, under focusing conditions and at room temperature, P m Will be higher than C×P m (1), which is higher than C times of 1 sun. That is to say, under low irradiance, since the density of complex states does not decrease, but the photon flux decreases, it will affect the conversion efficiency of the battery, that is, P m The reduction will not be in proportion to the reduction in photon flux, and this embodiment also takes the influence of this factor into consideration.

[0105] In this embodiment, 145 pieces of the above-mentioned sub-cells are connected in series to form a second solar cell 200. After being filtered by the first solar cell 100, the optimal output voltage of the PV characteristic curve of the second solar cell 200 is 86.4V, and the fill factor is 81.5%. The first solar cell 100 is bonded to the second solar cell 200, and the positive and negative electrodes corresponding to the first solar cell 100 and the second solar cell 200 are connected in parallel after anti-reverse measures are taken to obtain a stacked solar cell, which is used for outdoor power generation. In this embodiment, the output power of the single first solar cell 100 is 45W, the output power of the pure crystalline silicon solar cell is 55W, and the output power of the stacked solar cell is 76W, that is, the output power of the stacked solar cell is 40% higher than that of the single-junction perovskite cell, and 30% higher than that of the single crystalline silicon cell, and has higher performance.

[0106] Example 2

[0107] The stacked solar cell includes a top cell and a bottom cell, wherein the first solar cell 100 is the top cell and the second solar cell 200 is the bottom cell. 3 The first perovskite solar cell 100 has a characteristic working curve of PV curve, an open circuit voltage of 85V, a maximum power point voltage of 75V, and a fill factor of 79%. The maximum deviation output power coefficient is determined to be 0.90. On this basis, the first target voltage value V a is 67V, the second target voltage value V b The sub-cell of the second solar cell 200 adopts Topcon cell, and the open circuit voltage of the sub-cell of the second solar cell 200 is about 0.71V, and the optimal output voltage is 0.63V. 123 sub-cells are connected in series to form the second solar cell 200. After filtering by the first solar cell 100, the optimal output voltage of the PV characteristic curve of the second solar cell 200 is 72V, and the filling factor is 83%. The first solar cell 100 is bonded to the second solar cell 200, and the positive and negative electrodes corresponding to the first solar cell 100 and the second solar cell 200 are connected in parallel after anti-reverse measures are taken to obtain a stacked solar cell, which is used for outdoor power generation. In this embodiment, the output power of the single first solar cell 100 is 48W, the output power of the monocrystalline silicon solar cell is 60W, and the output power of the stacked solar cell is 79W, that is, the output power of the stacked solar cell is 39% higher than that of the single junction perovskite cell, and 29% higher than that of the monocrystalline silicon cell, and has higher performance.

[0108] Example 3

[0109] The stacked solar cell includes a top cell and a bottom cell, wherein the first solar cell 100 is the top cell and the second solar cell 200 is the bottom cell. The FaPbI based 2.7 Br 0.3 The first perovskite solar cell 100 has a characteristic working curve of PV curve, an open circuit voltage of 110V, a maximum power point voltage of 98V, and a fill factor of 80%. The maximum deviation output power coefficient is determined to be 0.97. On this basis, the first target voltage value V a is 94V, the second target voltage value V b is 99.5V. The sub-cell of the second solar cell 200 adopts HJT cell, the open circuit voltage of the sub-cell of the second solar cell 200 is about 0.745V, the optimal output voltage is 0.64V, and 155 sub-cells are connected in series to form the second solar cell 200. After filtering by the first solar cell 100, the optimal output voltage of the PV characteristic curve of the second solar cell 200 is 97.4V, and the fill factor is 84%. The first solar cell 100 is bonded to the second solar cell 200, and the positive and negative electrodes corresponding to the first solar cell 100 and the second solar cell 200 are connected in parallel after anti-reverse measures are taken to obtain a stacked solar cell, which is used for outdoor power generation. In this embodiment, the output power of the single first solar cell 100 is 54W, the output power of the pure crystalline silicon solar cell is 68W, and the output power of the stacked solar cell is 90W, that is, the output power of the stacked solar cell is 41% higher than that of the single junction perovskite cell, and 29.5% higher than that of the single crystalline silicon cell, and has higher performance.

[0110] Example 4

[0111] The tandem solar cell comprises a top cell and a tandem cell, that is, the tandem solar cell comprises a top cell, a bottom cell and at least one middle cell, wherein the first solar cell 100 is the top cell and the second solar cell 200 is the tandem cell. 0.1 Fa 0.9 PbI 2.0 Br 1.0 The characteristic working curve of the first perovskite solar cell 100 is a PV curve, the open circuit voltage is 10.5V, the maximum power point voltage is 9.5V, and the fill factor is 82%. The maximum deviation output power coefficient is determined to be 0.97. On this basis, the first target voltage value V a is 9.2V, and the second target voltage value V bThe sub-cell of the second solar cell 200 adopts a perovskite-perovskite stacked cell. The open circuit voltage of the sub-cell of the second solar cell 200 is about 0.97V, and the optimal output voltage is 0.79V. 13 perovskite-perovskite stacked cells are connected in series to form the second solar cell 200. After filtering by the first solar cell 100, the optimal output voltage of the PV characteristic curve of the second solar cell 200 is 9.4V, and the fill factor is 83%. The first solar cell 100 is bonded to the second solar cell 200, and the positive and negative electrodes corresponding to the first solar cell 100 and the second solar cell 200 are connected in parallel after anti-reverse measures are taken to obtain a stacked solar cell, which is used for outdoor power generation. In this embodiment, by measuring the output power of the stacked solar cell around the clock, it can be determined that the stacked solar cell has a power output that is 10-15% higher than that of a single first solar cell 100. It is 8-12% higher than a single second solar cell 200, and the output performance is higher.

[0112] In summary, the circuit topology determination method provided in the embodiment of the present application includes determining the characteristic output curve of the first solar cell 100, wherein the characteristic output curve represents the mapping relationship between the output voltage and the output power of the first solar cell 100 under set operating conditions; determining the target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell 100 under set operating conditions, wherein the output voltage corresponding to the maximum output power of the first solar cell 100 under set operating conditions is within the target output voltage range; determining the target circuit topology of the sub-cell of the second solar cell 200 at least according to the target output voltage range, so that the optimal output voltage of the second solar cell 200 is within the target output voltage range, wherein the optimal output voltage of the second solar cell 200 is the output voltage corresponding to the maximum output power of the second solar cell 200. The circuit topology determination method provided in the embodiment of the present application determines the target output voltage range according to the characteristic output curve of the first solar cell 100, and the output power range corresponding to the target output voltage range is at a relatively high level. The target circuit topology of the subcell of the second solar cell 200 is determined according to the target output voltage range, which can better match the power generation output characteristics, so that the voltage of the second solar cell 200 is within a better voltage range, and higher photoelectric conversion and power output are achieved. In addition, through the coupling adaptation of the second solar cell 200 to the first solar cell 100, a two-terminal stacked cell without an intermediate charge transfer layer can be formed, which can realize double-junction power generation and one-way convergence, greatly achieving the purpose of reducing costs and increasing efficiency, and improving the problem of low power generation efficiency caused by series current mismatch in existing stacked solar cells.

[0113] The manufacturing method of the stacked solar cell provided in the embodiment of the present application includes using the above-mentioned circuit topology determination method to determine the circuit topology structure of the second solar cell 200; the stacked solar cell provided in the embodiment of the present application is manufactured by the above-mentioned manufacturing method, and therefore has the advantage of high power generation efficiency.

[0114] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A method for determining a circuit topology structure, for determining a target circuit topology structure of a solar cell in a stacked solar cell, wherein the stacked solar cell comprises a first solar cell and a second solar cell, wherein the second solar cell comprises a plurality of sub-cells, wherein: The method for determining the circuit topology structure comprises: determining a characteristic output curve of the first solar cell, wherein the characteristic output curve represents a mapping relationship between an output voltage and an output power of the first solar cell under set operating conditions; determining a target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under the set operating conditions, wherein the output voltage corresponding to the maximum output power of the first solar cell under the set operating conditions is within the target output voltage range; At least according to the target output voltage range, a target circuit topology of the sub-cells of the second solar cell is determined so that the optimal output voltage of the second solar cell is within the target output voltage range, wherein the optimal output voltage of the second solar cell is an output voltage corresponding to when the output power of the second solar cell is maximum.

2. The method for determining a circuit topology structure according to claim 1, characterized in that: The step of determining a target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under the set operating conditions comprises: determining the maximum output power of the first solar cell under the set operating conditions according to the characteristic output curve; Determine the allowable loss power, and subtract the allowable loss power from the maximum output power to obtain the allowable maximum deviation output power, wherein the allowable loss power is a preset value or a preset ratio of the maximum output power, and the preset ratio has a value range of (0,0.4]; According to the characteristic output curve and the maximum allowable deviation output power, a first target voltage value and a second target voltage value corresponding to the maximum allowable deviation output power are determined, the first target voltage value is smaller than the second target voltage value, the first target voltage value is determined as the lower limit value of the target output voltage range, and the second target voltage value is determined as the upper limit value of the target output voltage range.

3. The method for determining a circuit topology structure according to claim 2, characterized in that: The value range of the preset ratio is (0, 0.2].

4. The method for determining a circuit topology structure according to claim 1, characterized in that: The step of determining a target output voltage range according to the characteristic output curve and the maximum output power of the first solar cell under the set operating conditions comprises: determining the maximum output power of the first solar cell under the set operating conditions according to the characteristic output curve; Determine the allowable loss power, and subtract the allowable loss power from the maximum output power to obtain the allowable maximum deviation output power, wherein the allowable loss power is a preset value or a preset ratio of the maximum output power, and the preset ratio has a value range of (0,0.4]; Determining, according to the characteristic output curve and the maximum allowable deviation output power, a first initial voltage value and a second initial voltage value corresponding to the maximum allowable deviation output power, wherein the first initial voltage value is less than the second initial voltage value; Determine a first voltage deviation coefficient and a second voltage deviation coefficient, determine the product of the first initial voltage value and the first voltage deviation coefficient as a third target voltage value, determine the product of the second initial voltage value and the second voltage deviation coefficient as a fourth target voltage value, determine the third target voltage value as a lower limit value of the target output voltage range, and determine the fourth target voltage value as an upper limit value of the target output voltage range.

5. The method for determining a circuit topology structure according to claim 1, characterized in that: The step of determining a target circuit topology of a sub-cell of the second solar cell according to at least the target output voltage range comprises: Determining an optimal output voltage of a sub-cell of the second solar cell, wherein the optimal output voltage of the sub-cell is an output voltage corresponding to a maximum output power of the sub-cell; Determining a target number of series-connected subcells and a target number of parallel-connected subcells of the second solar cell according to the optimal output voltage of the subcells of the second solar cell and the target output voltage range; The target circuit topology of the sub-cells of the second solar cell is determined according to the target number of series connections and the target number of parallel connections of the sub-cells of the second solar cell, wherein the number of series connections of the sub-cells of the second solar cell in the target circuit topology satisfies the target number of series connections, and the number of parallel connections of the sub-cells of the second solar cell in the target circuit topology satisfies the target number of parallel connections.

6. The method for determining a circuit topology structure according to claim 1, characterized in that: The stacked solar cell comprises a bottom cell, a top cell and at least one layer of middle cell stacked between the top cell and the bottom cell; One of the first solar cell and the second solar cell is the top cell, and the other is the middle cell adjacent to the top cell; or, the first solar cell and the second solar cell are two adjacent middle cells; or, one of the first solar cell and the second solar cell is the bottom cell, and the other is the middle cell adjacent to the bottom cell.

7. The method for determining a circuit topology structure according to claim 1, characterized in that: The step of determining a characteristic output curve of the first solar cell comprises: Determining the set operating conditions, the set operating conditions at least including a spectrum value of a target environment and a target operating temperature of the first solar cell; A mapping relationship between the output voltage and the output power of the first solar cell under the set operating conditions is determined to obtain a characteristic output curve of the first solar cell.

8. A method for manufacturing a stacked solar cell, characterized in that: include: providing a first solar cell; connecting the plurality of sub-cells according to a target circuit topology to obtain a second solar cell, wherein the target circuit topology is determined according to the method for determining a circuit topology according to any one of claims 1 to 7; The first solar cell and the second solar cell are stacked to obtain a stacked solar cell.

9. The method for manufacturing a stacked solar cell according to claim 8, characterized in that: The first solar cell is a perovskite cell, and the second solar cell is a crystalline silicon cell.

10. A stacked solar cell, characterized in that: The laminated solar cell is manufactured by the manufacturing method of claim 8 or 9.

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