Method and device for evaluating output power of bifacial photovoltaic module under shadow blocking scenario

Abstract

The embodiment of the application discloses a method and device for evaluating output power of a double-sided photovoltaic module in a shadow shielding scene, and is applied to the technical field of double-sided photovoltaic modules. Firstly, according to the shadow area percentage and the five parameters of the front side and the back side of the double-sided photovoltaic cell under standard test conditions, the five parameters of the shadow and non-shadow areas of the front side and the back side of the cell under the standard test conditions are calculated respectively. Secondly, according to the radiation shielding ratio, the five parameters of the shadow and non-shadow areas of the front side and the back side of the cell under the shadow shielding scene are calculated respectively. Thirdly, a double-current source model of the double-sided photovoltaic cell under the shadow shielding scene is constructed, and the five parameters of the front side and the back side of the photovoltaic cell under the shadow shielding scene are calculated respectively. Finally, a parallel equivalent circuit model is constructed, the target five parameters of a single double-sided photovoltaic cell under the shadow shielding scene are calculated, and based on this, the I-V characteristic equation of the cell, the cell string and the module is calculated in turn, so that the output power of the double-sided photovoltaic module under the shadow shielding scene is accurately evaluated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bifacial photovoltaic modules, in particular to a method and device for evaluating the output power of bifacial photovoltaic modules under shadow blocking scenarios. BACKGROUND

[0002] Bifacial photovoltaic modules can absorb solar energy on both the front side and the back side to generate electricity. They are attracting more and more attention due to their lower levelized cost of energy (LCOE). However, during actual operation, the mutual blocking between modules can cause uneven radiation distribution on the front and back sides of bifacial photovoltaic modules. Under the aforementioned uneven radiation conditions, electrical mismatch occurs between the cells of the modules, resulting in a decrease in the total output power of the modules.

[0003] Existing photovoltaic power generation models take into account shadow blocking scenarios, as described in Figure 1 , (a) is a shadow blocking type in which the radiation intensity of the same cell in a photovoltaic module is uniformly distributed, but the radiation intensity between cells is uneven. (b) is a shadow blocking type in which there is a difference in radiation intensity in different regions of the same cell. For the shadow blocking type shown in (b), existing photovoltaic power generation models generally use area-weighted average method to calculate the total radiation of each region of the same cell, ignoring the electrical mismatch between the shadow region and the non-shadow region of the cell, thereby causing simulation errors. In addition, existing models generally use a constant bifacial coefficient to measure the ratio of the backside power generation performance to the frontside power generation performance of bifacial photovoltaic modules, and calculate the dynamic output power of bifacial photovoltaic modules accordingly. However, when the radiation conditions on the front / back side of bifacial photovoltaic modules change or complex shadow blocking as shown in Figure 1 occurs, the power generation performance on the front / back side will change, and the traditional constant bifacial coefficient method is no longer applicable.

[0004] In summary, the existing models have limited application scenarios, especially in simulating the output power of bifacial modules under local shadow blocking conditions on the front and back sides. In addition, existing models do not fully consider the effects of radiation intensity and shadow blocking on the power generation performance of bifacial modules on the front and back sides, resulting in inaccurate simulation of the dynamic output power of bifacial modules and simulation errors. SUMMARY

[0005] Therefore, the present application provides a method and device for evaluating the output power of bifacial photovoltaic modules under shadow blocking scenarios, which can accurately evaluate the dynamic output power of bifacial photovoltaic modules.

[0006] To solve the above problems, the technical solutions provided by the present application are as follows:

[0007] In a first aspect, the embodiments of the present application provide a method for evaluating output power of a bifacial photovoltaic module in a shadow shielding scenario, the bifacial photovoltaic module being connected by a plurality of single-piece bifacial photovoltaic cells, and the method comprising:

[0008] calculating five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under standard test conditions, the five parameters including photo-generated current, dark saturation current of a diode, series resistance, parallel resistance, and diode thermal voltage;

[0009] determining a shadow area percentage and a radiation shielding ratio of the single-piece bifacial photovoltaic cell, the shadow area percentage and the radiation shielding ratio being used to represent a shadow shielding condition of the single-piece bifacial photovoltaic cell;

[0010] calculating five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell in the shadow shielding scenario according to a pre-constructed double-current source model of the bifacial photovoltaic cell in the shadow shielding scenario, the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under the standard test conditions, the shadow area percentage, and the radiation shielding ratio;

[0011] calculating target five parameters of the single-piece bifacial photovoltaic cell in the shadow shielding scenario according to a pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell and the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell in the shadow shielding scenario;

[0012] calculating I-V characteristic equations of the single-piece bifacial photovoltaic cell, the bifacial photovoltaic cell string, and the bifacial photovoltaic module in sequence based on the target five parameters of the single-piece bifacial photovoltaic cell in the shadow shielding scenario, and determining output power of the bifacial photovoltaic module in the shadow shielding scenario.

[0013] In a possible implementation manner, the calculating of the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under the standard test conditions comprises:

[0014] obtaining front side rated parameters, back side rated parameters, and internal circuit characteristics of the bifacial photovoltaic module;

[0015] calculating five parameters of the front side of the bifacial photovoltaic module under the standard test conditions by using a preset I-V characteristic equation and the front side rated parameters;

[0016] calculating five parameters of the back side of the bifacial photovoltaic module under the standard test conditions by using a preset I-V characteristic equation and the back side rated parameters;

[0017] calculating the five parameters of the front side of the single-piece bifacial photovoltaic cell under the standard test conditions based on the five parameters of the front side of the bifacial photovoltaic module under the standard test conditions and the internal circuit characteristics of the bifacial photovoltaic module;

[0018] calculate the five parameters of the back side of the single piece of the bifacial photovoltaic cell under the standard test condition based on the five parameters of the back side of the component under the standard test condition and the internal circuit characteristics of the bifacial photovoltaic component.

[0019] In a possible implementation manner, the determining the shadow area percentage and the radiation shielding ratio of the single piece of the bifacial photovoltaic cell comprises the following steps.

[0020] acquiring a shadow area, a shadow area radiation intensity, a non-shadow area, and a non-shadow area radiation intensity of the single piece of the bifacial photovoltaic cell under the shadow shielding scenario;

[0021] determining the shadow area percentage based on the shadow area and the non-shadow area;

[0022] determining the radiation shielding ratio based on the shadow area radiation intensity and the non-shadow area radiation intensity.

[0023] In a possible implementation manner, the calculating the five parameters of the front side and the back side of the single piece of the bifacial photovoltaic cell under the shadow shielding scenario based on the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the front side and the back side of the single piece of the bifacial photovoltaic cell under the standard test condition, the shadow area percentage, and the radiation shielding ratio comprises the following steps.

[0024] calculating, according to the shadow area percentage and the five parameters of the front side and the back side of the single piece of the bifacial photovoltaic cell under the standard test condition, the five parameters of the front side shadow area, the front side non-shadow area, the back side shadow area, and the back side non-shadow area of the single piece of the bifacial photovoltaic cell under the standard test condition;

[0025] calculating, according to the radiation shielding ratio, the five parameters of the front side shadow area, the front side non-shadow area, the back side shadow area, and the back side non-shadow area of the single piece of the bifacial photovoltaic cell under the standard test condition, the five parameters of the front side shadow area, the front side non-shadow area, the back side shadow area, and the back side non-shadow area of the single piece of the bifacial photovoltaic cell under the shadow shielding scenario;

[0026] in the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the front side of the single piece of the bifacial photovoltaic cell under the shadow shielding scenario are calculated based on the five parameters of the front side shadow area of the single piece of the bifacial photovoltaic cell under the shadow shielding scenario and the five parameters of the front side non-shadow area of the single piece of the bifacial photovoltaic cell under the shadow shielding scenario;

[0027] In the double-current source model of the pre-constructed bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the back side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario are calculated based on the five parameters of the back side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario and the five parameters of the back side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario.

[0028] In a possible implementation manner, the I-V characteristic equation of the single-piece bifacial photovoltaic cell under the shadow shielding scenario is calculated based on the target five parameters of the single-piece bifacial photovoltaic cell under the shadow shielding scenario, and the I-V characteristic equations of the bifacial photovoltaic cell string and the bifacial photovoltaic module are sequentially calculated to determine the output power of the bifacial photovoltaic module under the shadow shielding scenario, including:

[0029] The I-V characteristic equation of the single-piece bifacial photovoltaic cell under the shadow shielding scenario is calculated based on the target five parameters of the single-piece bifacial photovoltaic cell under the shadow shielding scenario.

[0030] The I-V characteristic equation of the bifacial photovoltaic cell string under the shadow shielding scenario is calculated based on the I-V characteristic equation of the single-piece bifacial photovoltaic cell.

[0031] The I-V characteristic equation of the bifacial photovoltaic module under the shadow shielding scenario is calculated based on the I-V characteristic equation of the bifacial photovoltaic cell string.

[0032] The output power of the bifacial photovoltaic module under the shadow shielding scenario is determined based on the I-V characteristic equation of the bifacial photovoltaic module.

[0033] In a second aspect, the embodiments of the present application provide an evaluation device for output power of a bifacial photovoltaic module under a shadow shielding scenario, the bifacial photovoltaic module being connected by a plurality of single-piece bifacial photovoltaic cells, and the evaluation device comprising:

[0034] A first calculation module is configured to calculate five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under standard test conditions, the five parameters including a photo-generated current, a dark saturation current of a diode, a series resistance, a parallel resistance, and a diode thermal voltage.

[0035] A first determination module is configured to determine a shadow area percentage and a radiation shielding ratio of the single-piece bifacial photovoltaic cell, the shadow area percentage and the radiation shielding ratio being used to represent a shadow shielding condition of the single-piece bifacial photovoltaic cell.

[0036] A second calculation module is configured to calculate five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario according to a double-current source model of a pre-constructed bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under the standard test conditions, the shadow area percentage, and the radiation shielding ratio.

[0037] a third calculation module, configured to calculate target five parameters of the single-piece bifacial photovoltaic cell in the shadow blocking scenario according to a pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell, and the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell in the shadow blocking scenario;

[0038] a second determination module, configured to sequentially calculate I-V characteristic equations of the single-piece bifacial photovoltaic cell, the bifacial photovoltaic cell string, and the bifacial photovoltaic module based on the target five parameters of the single-piece bifacial photovoltaic cell in the shadow blocking scenario, and determine output power of the bifacial photovoltaic module in the shadow blocking scenario.

[0039] In a possible implementation manner, the first calculation module is specifically configured to:

[0040] obtain front side rated parameters, back side rated parameters, and internal circuit characteristics of the bifacial photovoltaic module;

[0041] calculate five parameters of a front side of the bifacial photovoltaic module in a standard test condition by using a preset I-V characteristic equation and the front side rated parameters;

[0042] calculate five parameters of a back side of the bifacial photovoltaic module in the standard test condition by using the preset I-V characteristic equation and the back side rated parameters;

[0043] calculate the five parameters of the front side of the single-piece bifacial photovoltaic cell in the standard test condition based on the five parameters of the front side of the bifacial photovoltaic module in the standard test condition and the internal circuit characteristics of the bifacial photovoltaic module;

[0044] calculate the five parameters of the back side of the single-piece bifacial photovoltaic cell in the standard test condition based on the five parameters of the back side of the bifacial photovoltaic module in the standard test condition and the internal circuit characteristics of the bifacial photovoltaic module.

[0045] In a possible implementation manner, the first determination module is specifically configured to:

[0046] obtain a shadow area, a shadow area radiation intensity, a non-shadow area, and a non-shadow area radiation intensity of the single-piece bifacial photovoltaic cell in the shadow blocking scenario, determine the shadow area percentage based on the shadow area and the non-shadow area, and determine the radiation blocking ratio based on the shadow area radiation intensity and the non-shadow area radiation intensity.

[0047] In a possible implementation manner, the second calculation module is specifically configured to:

[0048] According to the shadow area percentage and the five parameters of the front / rear side of the single piece of bifacial photovoltaic cell under standard test conditions, the front side shadow area five parameters, the front side non-shadow area five parameters, the rear side shadow area five parameters and the rear side non-shadow area five parameters of the single piece of bifacial photovoltaic cell under standard test conditions are respectively calculated;

[0049] According to the radiation shielding ratio, the front side shadow area five parameters, the front side non-shadow area five parameters, the rear side shadow area five parameters and the rear side non-shadow area five parameters of the single piece of bifacial photovoltaic cell under standard test conditions, the front side shadow area five parameters, the front side non-shadow area five parameters, the rear side shadow area five parameters and the rear side non-shadow area five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario are calculated;

[0050] In the double-current source model of the pre-constructed bifacial photovoltaic cell under the shadow shielding scenario, the front side five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario are calculated based on the front side shadow area five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario and the front side non-shadow area five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario;

[0051] In the double-current source model of the pre-constructed bifacial photovoltaic cell under the shadow shielding scenario, the rear side five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario are calculated based on the rear side shadow area five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario and the rear side non-shadow area five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario.

[0052] In a possible implementation manner, the second determining module is specifically configured to:

[0053] The I-V characteristic equation of the single piece of bifacial photovoltaic cell under the shadow shielding scenario is calculated by using the target five parameters of the single piece of bifacial photovoltaic cell under the shadow shielding scenario;

[0054] The I-V characteristic equation of the bifacial photovoltaic cell string under the shadow shielding scenario is calculated based on the I-V characteristic equation of the single piece of bifacial photovoltaic cell;

[0055] The I-V characteristic equation of the bifacial photovoltaic module under the shadow shielding scenario is calculated based on the I-V characteristic equation of the bifacial photovoltaic cell string;

[0056] The output power of the bifacial photovoltaic module under the shadow shielding scenario is determined based on the I-V characteristic equation of the bifacial photovoltaic module.

[0057] In a third aspect, the present application provides an evaluation device for output power of a bifacial photovoltaic module under a shadow shielding scenario, the device comprising: a processor, a memory, a system bus;

[0058] The processor and the memory are connected through the system bus;

[0059] The memory is configured to store one or more programs, the one or more programs comprising instructions that, when executed by the processor, cause the processor to perform the method for evaluating output power of a bifacial photovoltaic module in a shadow blocking scenario according to the first aspect.

[0060] In a fourth aspect, the present application provides a computer-readable storage medium storing instructions that, when executed on a device, cause the device to perform the method for evaluating output power of a bifacial photovoltaic module in a shadow blocking scenario according to the first aspect.

[0061] Therefore, the present application has the following beneficial effects:

[0062] The present application provides a method for evaluating output power of a bifacial photovoltaic module in a shadow blocking scenario. The bifacial photovoltaic module is connected by a plurality of single bifacial photovoltaic cells. The method comprises: calculating five parameters of the front and back sides of the single bifacial photovoltaic cell under standard test conditions, the five parameters including photo-generated current, dark saturation current of a diode, series resistance, parallel resistance, and diode thermal voltage; determining a shadow area percentage and a radiation blocking ratio of the single bifacial photovoltaic cell, the shadow area percentage and the radiation blocking ratio being used to represent the shadow blocking condition of the single bifacial photovoltaic cell; calculating five parameters of the front and back sides of the single bifacial photovoltaic cell in the shadow blocking scenario according to a pre-constructed double-current source model of the bifacial photovoltaic cell in the shadow blocking scenario, the five parameters of the front and back sides of the single bifacial photovoltaic cell under the standard test conditions, the shadow area percentage, and the radiation blocking ratio; calculating target five parameters of the single bifacial photovoltaic cell in the shadow blocking scenario according to a pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell and the five parameters of the front and back sides of the single bifacial photovoltaic cell in the shadow blocking scenario; and calculating I-V characteristic equations of the single bifacial photovoltaic cell, a bifacial photovoltaic cell string, and the bifacial photovoltaic module in sequence based on the target five parameters, and determining output power of the bifacial photovoltaic module in the shadow blocking scenario.

[0063] Thus, a double-current source model of the bifacial photovoltaic cell under the shadow shielding scene is constructed, five parameters of the front side of the single bifacial photovoltaic cell under the shadow shielding scene and five parameters of the back side of the single bifacial photovoltaic cell under the shadow shielding scene are calculated respectively, and the electrical mismatch problem existing between the shadow area and the non-shadow area of the cell can be considered; a parallel equivalent circuit model of the bifacial photovoltaic cell considering the dynamic power generation characteristics of the front / back side of the bifacial photovoltaic cell is constructed, and is used to calculate the five parameters of the front / back side of the single bifacial photovoltaic cell. The composite electrical model is established by combining the two sub-models, the target five parameters of the single bifacial photovoltaic cell under the complex shadow shielding scene are calculated, and the I-V characteristic equation of the cell, the cell string and the module is calculated in turn based on this, so that the dynamic output power of the bifacial photovoltaic module under the complex front / back side shadow shielding scene can be accurately evaluated.

[0064] The embodiment of the present application also provides a device corresponding to the above method, which has the same beneficial effects as the above method. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 A shadow shielding type diagram provided for the embodiment of the present application;

[0066] Figure 2 An equivalent circuit diagram of a photovoltaic module provided for the embodiment of the present application;

[0067] Figure 3 A flowchart of an evaluation method of output power of a bifacial photovoltaic module under a shadow shielding scene provided for the embodiment of the present application;

[0068] Figure 4 An internal circuit diagram of a bifacial photovoltaic module provided for the embodiment of the present application;

[0069] Figure 5 A shadow area distribution diagram of a single bifacial photovoltaic cell under a shadow shielding scene provided for the embodiment of the present application;

[0070] Figure 6 A double-current source model diagram of a bifacial photovoltaic cell under a shadow shielding scene provided for the embodiment of the present application;

[0071] Figure 7 A parallel model diagram of a single bifacial photovoltaic cell front side and back side in parallel provided for the embodiment of the present application;

[0072] Figure 8 A parallel equivalent circuit model diagram of a bifacial photovoltaic cell provided for the embodiment of the present application;

[0073] Figure 9 A composite electrical model diagram provided for the embodiment of the present application;

[0074] Figure 10A target five-parameter calculation process schematic diagram provided for an embodiment of the present application;

[0075] Figure 11 Another flowchart of a method for evaluating output power of a bifacial photovoltaic module in a shadow blocking scenario provided for an embodiment of the present application;

[0076] Figure 12 A structure schematic diagram of an evaluation device for output power of a bifacial photovoltaic module in a shadow blocking scenario provided for an embodiment of the present application;

[0077] Figure 13 A structure schematic diagram of an evaluation device for output power of a bifacial photovoltaic module in a shadow blocking scenario provided for an embodiment of the present application. DETAILED DESCRIPTION

[0078] The technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0079] In the present application, relationship terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. The terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0080] The existing model usually uses the bifacial coefficient measured under standard test conditions (STC) to calculate the equivalent radiation G E of the bifacial photovoltaic module. E G pv is taken as the actual radiation intensity G of the bifacial photovoltaic module, and is substituted into the equivalent circuit model to calculate the total output power of the bifacial photovoltaic module.

[0081] Wherein, STC refers to the standard conditions for testing solar cells, i.e. the solar radiation intensity is 1000 W / m2 The double-sided coefficient is the minimum value of the ratio between the main electrical characteristics of the rear side and the front side of the double-sided photovoltaic module, and the double-sided coefficient under standard test conditions is The calculation formula of the equivalent radiation G E The calculation formula of the equivalent radiation G

[0082]

[0083] In the formula: and are the short-circuit current and the maximum power of the front side of the double-sided photovoltaic module under STC conditions, respectively. and are the short-circuit current and the maximum power of the rear side of the double-sided photovoltaic module under STC conditions, respectively. F represents the front side radiation intensity; and R represents the rear side radiation intensity.

[0084] The equivalent circuit model is an electrical model for simulating the output power of a photovoltaic module, and a schematic diagram of the equivalent circuit is shown in Figure 2 The voltage-current relationship of the double-sided photovoltaic module can be seen from formula (3).

[0085]

[0086] In the formula: I ph is the photo-generated current of the double-sided photovoltaic module, I d is the current flowing through the diode, I p is the current flowing through the parallel resistor, I0 is the dark saturation current of the diode, R s is the series resistance of the double-sided photovoltaic module, R p is the parallel resistance of the double-sided photovoltaic module, V t is the thermal voltage of the diode.

[0087] I ph , I0, R s , R p and V t are five unknown parameters in formula (3), and the five parameters under STC conditions: I ph,stc , V t,stc , I 0,stc , R p,stc , R s,stc can be solved by substituting the parameters on the nameplate of the photovoltaic module into formula (3).

[0088] The sizes of the five unknown parameters are affected by the actual temperature T pv of the photovoltaic module and the actual radiation intensity G pvThe formula (4) can convert the five parameters of the component STC working condition into the five parameters of the actual working condition:

[0089]

[0090] In the formula, G pv is the actual radiation intensity of the component; G stc is the radiation intensity under the standard test condition (1000 W / m 2 ); T pv is the actual temperature of the component; T stc is the component temperature under the standard test condition (273.15 K); α is the short-circuit current temperature coefficient, q e is the electronic charge (1.6 x 10 -19 C); E g is the energy band gap, and K0 is the Boltzmann constant (1.38 x 10 -23 J / K).

[0091] After the five parameters of the actual working condition are substituted into the formula (3) to obtain the I-V characteristic equation of the actual working condition, the output power of the bifacial photovoltaic component under the actual working condition can be calculated.

[0092] When the radiation conditions of the front side and the back side of the bifacial photovoltaic component change or the complex shadow shielding shown in Figure 1 occurs, the power generation performance of the front side and the back side changes, and the method of simply using the constant bifacial coefficient to calculate the dynamic output power of the bifacial component will cause simulation errors. In addition, when the shadow shielding shown in Figure 1 (b) occurs between the front side and the back side of the current bifacial component, the radiation of each area of the same cell is usually area-weighted and averaged. This method ignores the electrical mismatching problem between the shadow area and the non-shadow area of the cell, and thus simulation errors are caused. In summary, the existing method is difficult to accurately simulate the output power of the bifacial component under the complex front side and back side shadow shielding scene.

[0093] The embodiment of the present application provides an evaluation method and device for the output power of a bifacial photovoltaic component under a shadow shielding scene. The bifacial photovoltaic component is connected by a plurality of single-piece bifacial photovoltaic cells. The evaluation method not only considers the dynamic electrical performance of the front side and the back side of the bifacial photovoltaic component, but also can effectively process the power generation characteristics of the front side and the back side of the component under the complex shadow shielding condition.

[0094] The evaluation method comprises the following steps: calculating five parameters of the front / rear side of the single-piece bifacial photovoltaic cell under standard test conditions, the five parameters comprising photo-generated current, dark saturation current of a diode, series resistance, parallel resistance and diode thermal voltage; determining a shadow area percentage and a radiation shielding ratio of the single-piece bifacial photovoltaic cell, the shadow area percentage and the radiation shielding ratio being used to represent a shadow shielding condition of the single-piece bifacial photovoltaic cell; calculating five parameters of the front / rear side of the single-piece bifacial photovoltaic cell under the shadow shielding condition according to a pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding condition, the five parameters of the front / rear side of the single-piece bifacial photovoltaic cell under the standard test conditions, the shadow area percentage and the radiation shielding ratio; calculating target five parameters of the single-piece bifacial photovoltaic cell under the shadow shielding condition according to a pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell and the five parameters of the front / rear side of the single-piece bifacial photovoltaic cell under the shadow shielding condition; and sequentially calculating I-V characteristic equations of the single-piece bifacial photovoltaic cell, the bifacial photovoltaic cell string and the bifacial photovoltaic module based on the target five parameters, so as to determine output power of the bifacial photovoltaic module under the shadow shielding condition.

[0095] The double-current source model of the bifacial photovoltaic cell under the shadow shielding condition is constructed, the five parameters of the front side of the single-piece bifacial photovoltaic cell under the shadow shielding condition and the five parameters of the rear side of the single-piece bifacial photovoltaic cell under the shadow shielding condition are calculated respectively, and the electrical mismatching problem existing between the shadow area and the non-shadow area of the cell can be considered; the parallel equivalent circuit model of the bifacial photovoltaic cell considering dynamic power generation characteristics of the front / rear side of the bifacial photovoltaic cell is constructed, so as to calculate the five parameters of the front / rear side of the single-piece bifacial photovoltaic cell as a whole. The composite electrical model is established in combination with the two sub-models, the target five parameters of the single-piece bifacial photovoltaic cell under the complex shadow shielding condition are calculated, and the I-V characteristic equations of the cell, the cell string and the module are sequentially calculated based on the target five parameters, so that the dynamic output power of the bifacial photovoltaic module under the complex front / rear side shadow shielding condition can be accurately evaluated.

[0096] In order to facilitate understanding of the technical solutions provided in the embodiments of the present application, the evaluation method and device for output power of a bifacial photovoltaic module under a shadow shielding condition provided in the embodiments of the present application will be described below in combination with the accompanying drawings.

[0097] Referring to Figure 3 , Figure 3 A flowchart of the evaluation method for output power of a bifacial photovoltaic module under a shadow shielding condition provided in the embodiments of the present application is shown in the figure, and the method specifically comprises S301-S305.

[0098] The bifacial photovoltaic module is generally composed of a plurality of bifacial photovoltaic cell strings, and each bifacial photovoltaic cell string is composed of a single-piece bifacial photovoltaic cell in series and a bypass diode. Referring to Figure 4 , Figure 4A double-sided photovoltaic module internal circuit schematic diagram provided by the embodiment of the application, n is the number of double-sided photovoltaic cell strings in the double-sided photovoltaic module, and m is the number of single double-sided photovoltaic cells protected by the bypass diode in the double-sided photovoltaic cell string.

[0099] The five parameters of the front side and the back side of each single double-sided photovoltaic cell under the shadow shielding scenario are calculated by using the pre-constructed electrical sub-model 1 (a double-current source model of the double-sided photovoltaic cell under the shadow shielding scenario). For details, refer to the embodiment disclosed in the following step S303.

[0100] The target five parameters of the single double-sided photovoltaic cell are accurately calculated when the front side and the back side radiation conditions change by using the pre-constructed electrical sub-model 2 (a parallel equivalent circuit model of the double-sided photovoltaic cell) considering the dynamic power generation characteristics of the front side and the back side of the single double-sided photovoltaic cell. For details, refer to the embodiment disclosed in the following step S304. The output power of the double-sided photovoltaic module is further determined based on the target five parameters.

[0101] It should be noted that the calculation of the five parameters under different scenarios is realized in parallel. The calculation sequence of the five parameters shown in the embodiment of the application is only an example, and does not constitute a limitation.

[0102] S301: Calculate the five parameters of the front side and the back side of the single double-sided photovoltaic cell under standard test conditions.

[0103] The five parameters of the front side and the back side of the single double-sided photovoltaic cell under standard test conditions are calculated, that is, the five parameters of the front side of the single double-sided photovoltaic cell under standard test conditions and the five parameters of the back side of the single double-sided photovoltaic cell under standard test conditions are calculated.

[0104] The front side rated parameters and the back side rated parameters are generally engraved on the nameplate of the double-sided photovoltaic module, and the front side rated parameters and the back side rated parameters are data under standard test conditions. The front side rated parameters and the back side rated parameters are substituted into the preset I-V characteristic equation shown in formula (3) to obtain the module front side five parameters and the module back side five parameters under standard test conditions, respectively. According to the internal circuit characteristics of the double-sided photovoltaic module, the five parameters of the front side of the single double-sided photovoltaic cell under standard test conditions and the five parameters of the back side of the single double-sided photovoltaic cell under standard test conditions are calculated.

[0105] In a possible implementation manner, the calculation of the five parameters of the front side and the back side of the single double-sided photovoltaic cell under standard test conditions includes:

[0106] The front side rated parameter, the rear side rated parameter and the internal circuit characteristic of the bifacial photovoltaic module are acquired; the preset I-V characteristic equation and the front side rated parameter are used to calculate the five parameters of the front side of the bifacial photovoltaic module under the standard test condition; the preset I-V characteristic equation and the rear side rated parameter are used to calculate the five parameters of the rear side of the bifacial photovoltaic module under the standard test condition; the five parameters of the front side of the single bifacial photovoltaic cell under the standard test condition are calculated based on the five parameters of the front side of the bifacial photovoltaic module under the standard test condition and the internal circuit characteristic of the bifacial photovoltaic module; and the five parameters of the rear side of the single bifacial photovoltaic cell under the standard test condition are calculated based on the five parameters of the rear side of the bifacial photovoltaic module under the standard test condition and the internal circuit characteristic of the bifacial photovoltaic module.

[0107] It can be known that the bifacial photovoltaic module is composed of n×m bifacial photovoltaic cells connected in series, and the parameters of each bifacial photovoltaic cell can be determined by the following formula (5). Figure 4

[0108]

[0109] In the formula, Iph, J0, Rsh, Rss and Vt respectively represent the five parameters of the single bifacial photovoltaic cell under the STC working condition, including the photo-generated current, the dark saturation current of the diode, the series resistance, the parallel resistance and the diode thermal voltage. The front side rated parameter on the nameplate is substituted into the preset I-V characteristic equation shown in the formula (3), so that the five parameters of the front side of the bifacial photovoltaic module under the STC working condition (Iph, J0, Rsh, Rss and Vt) are obtained, that is, the five parameters of the front side of the module.

[0110] The rear side rated parameter on the nameplate is substituted into the preset I-V characteristic equation shown in the formula (3), so that the five parameters of the rear side of the bifacial photovoltaic module under the STC working condition (Iph, J0, Rsh, Rss and Vt) are obtained, that is, the five parameters of the rear side of the module.

[0111]

[0112] According to the internal circuit characteristic of the bifacial photovoltaic module, the five parameters of the front side of the single bifacial photovoltaic cell under the STC working condition (Iph, J0, Rsh, Rss and Vt) are calculated by the foregoing formula (5); and the five parameters of the rear side of the single bifacial photovoltaic cell under the STC working condition (Iph, J0, Rsh, Rss and Vt) are calculated.

[0113] It should be noted that the specific steps provided in the present application are only one possible implementation, but are not limited to only this implementation, and can be set by the user as needed. ​​​​​​​​​​​

[0114] S302: Determine the percentage of shaded area and the radiation shading ratio of the monolithic bifacial photovoltaic cell, which are used to characterize the shadow shading condition of the monolithic bifacial photovoltaic cell.

[0115] In the shadow shading scenario, the distribution of the shadow area of the monolithic bifacial photovoltaic cell is shown in FIG. 2. As shown, the figure illustrates the shading condition of a single front or back side. The monolithic bifacial photovoltaic cell with an area of S includes a shadow area and a non-shadow area, wherein the area of the shadow area is S1, the radiation intensity of the shadow area is G1, the area of the non-shadow area is S2, and the radiation intensity of the non-shadow area is G2. The specific implementation of determining S, S1, S2, G1, and G2 is not limited in the embodiments of the present application, and can be selected according to actual needs. Figure 5

[0116] In one possible implementation, the determination of the percentage of shaded area and the radiation shading ratio of the monolithic bifacial photovoltaic cell includes: obtaining the area of the shadow area, the radiation intensity of the shadow area, the area of the non-shadow area, and the radiation intensity of the non-shadow area of the monolithic bifacial photovoltaic cell in the shadow shading scenario; determining the percentage of shaded area based on the area of the shadow area and the area of the non-shadow area; and determining the radiation shading ratio based on the radiation intensity of the shadow area and the radiation intensity of the non-shadow area.

[0117] Since the front side and the back side of the monolithic bifacial photovoltaic cell can be shaded, the embodiments of the present application can calculate the percentage of shaded area and the radiation shading ratio of the front side and the percentage of shaded area and the radiation shading ratio of the back side, respectively, when executed.

[0118] The percentage of shaded area (POSA) is sa (sa>0.01), which is calculated by formula (6). The radiation shading ratio (SR) is sr (sr>0.01), which is calculated by formula (7).

[0119]

[0120] The two indicators of POSA and SR can reflect the local shadow shading condition of the monolithic bifacial photovoltaic cell.

[0121] S303: Calculate the five parameters of the front side or the back side of the monolithic bifacial photovoltaic cell in the shadow shading scenario according to the pre-constructed double-current source model of the bifacial photovoltaic cell in the shadow shading scenario, the five parameters of the front side or the back side of the monolithic bifacial photovoltaic cell under the standard test condition, the percentage of shaded area, and the radiation shading ratio.

[0122] ​The mathematical relationship between the five parameters of the front side / back side of the single piece of bifacial photovoltaic cell under the shadow shielding scene and the POSA and the SR can be obtained through the pre-constructed double current source model of the bifacial photovoltaic cell under the shadow shielding scene.

[0123] The double current source model of the bifacial photovoltaic cell under the shadow shielding scene can be used to calculate the five parameters of any side of the single piece of bifacial photovoltaic cell under the local shadow shielding scene.

[0124] In a possible implementation manner, the five parameters of the front side / back side of the single piece of bifacial photovoltaic cell under the shadow shielding scene are calculated according to the pre-constructed double current source model of the bifacial photovoltaic cell under the shadow shielding scene, the five parameters of the front side / back side of the single piece of bifacial photovoltaic cell under the standard test condition, the shadow area percentage, and the radiation shielding ratio, and the method comprises the following steps.

[0125] The five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the back side shadow area, and the five parameters of the back side non-shadow area of the single piece of bifacial photovoltaic cell under the standard test condition are respectively calculated according to the shadow area percentage and the five parameters of the front side / back side of the single piece of bifacial photovoltaic cell under the standard test condition.

[0126] The five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the back side shadow area, and the five parameters of the back side non-shadow area of the single piece of bifacial photovoltaic cell under the shadow shielding scene are calculated according to the radiation shielding ratio, the five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the back side shadow area, and the five parameters of the back side non-shadow area of the single piece of bifacial photovoltaic cell under the standard test condition.

[0127] In the pre-constructed double current source model of the bifacial photovoltaic cell under the shadow shielding scene, the five parameters of the front side of the single piece of bifacial photovoltaic cell under the shadow shielding scene are calculated based on the five parameters of the front side shadow area of the single piece of bifacial photovoltaic cell under the shadow shielding scene and the five parameters of the front side non-shadow area of the single piece of bifacial photovoltaic cell under the shadow shielding scene.

[0128] In the pre-constructed double current source model of the bifacial photovoltaic cell under the shadow shielding scene, the five parameters of the back side of the single piece of bifacial photovoltaic cell under the shadow shielding scene are calculated based on the five parameters of the back side shadow area of the single piece of bifacial photovoltaic cell under the shadow shielding scene and the five parameters of the back side non-shadow area of the single piece of bifacial photovoltaic cell under the shadow shielding scene.

[0129] The five parameters of the front side shadow area of the single piece of bifacial photovoltaic cell under the STC working condition are calculated according to the shadow area percentage POSA and ) and the five parameters of the front-side non-shaded area under the STC condition ( and ); similarly, the five parameters of the rear-side shaded area of the single-piece bifacial photovoltaic cell under the STC condition ( and ) and the five parameters of the rear-side non-shaded area under the STC condition ( and ) are calculated according to the percentage of the shaded area POSA.

[0130] The five parameters of the front-side shaded area of the single-piece bifacial photovoltaic cell under the actual radiation condition ( and ) and the five parameters of the front-side non-shaded area under the actual radiation condition ( and ) are calculated according to the radiation shielding ratio SR; similarly, the five parameters of the rear-side shaded area of the single-piece bifacial photovoltaic cell under the actual radiation condition ( and ) and the five parameters of the rear-side non-shaded area under the actual radiation condition ( and ) are calculated according to the radiation shielding ratio SR.

[0131] In the embodiments of the present application, the actual radiation condition is the shadow shielding scene in actual application, and the following is represented by the shadow shielding scene.

[0132] After obtaining the five parameters of the front-side shaded area, the five parameters of the front-side non-shaded area, the five parameters of the rear-side shaded area, and the five parameters of the rear-side non-shaded area of the single-piece bifacial photovoltaic cell under the aforementioned shadow shielding scene, the five parameters of the front side of the single-piece bifacial photovoltaic cell under the shadow shielding scene ( and ) and the five parameters of the rear side of the single-piece bifacial photovoltaic cell under the shadow shielding scene ( and ) are calculated according to the double-current source model of the bifacial photovoltaic cell in the shadow shielding scene.

[0133] The modeling process and the calculation process of the five parameters of the front / rear side of the single-piece bifacial photovoltaic cell under the shadow shielding scene calculated by the embodiments of the present application are described below.

[0134] In the embodiments of the present application, since the photo-generated current of any one side of the single-piece bifacial photovoltaic cell is equal to the sum of the photo-generated current of the shaded area and the photo-generated current of the non-shaded area, it can be assumed that the shaded area and the non-shaded area of the single-piece bifacial photovoltaic cell are connected in parallel, and the double-current source model diagram of any one side of the single-piece bifacial photovoltaic cell under the shadow shielding scene is as shown in Figure 6 .

[0135] Figure 6 The light-generated current of the shadowed area, The light-generated current of the non-shadowed area, The series resistance of the shadowed area, The series resistance of the non-shadowed area, The parallel resistance of the shadowed area, The parallel resistance of the non-shadowed area, The current flowing through the diode in the parallel circuit, through the dark saturation current and the thermal voltage are calculated.

[0136] In specific embodiments, the light-generated current of the front side of a monolithic bifacial photovoltaic cell under the shadowed scenario and the light-generated current of the back side of a monolithic bifacial photovoltaic cell under the shadowed scenario are described.

[0137] Since the light-generated current is proportional to the cell area, the light-generated current of the shadowed area and the non-shadowed area of a cell under the STC condition and can be calculated according to the POSA, the light-generated current of the front side or the back side of a monolithic bifacial photovoltaic cell under the standard test condition and the percentage of the shadowed area.

[0138]

[0139] The above formula (8) is used to calculate the light-generated current of the shadowed area and the non-shadowed area of any side of a monolithic bifacial photovoltaic cell under the STC condition. The light-generated current of the shadowed area and the non-shadowed area of the front side of a monolithic bifacial photovoltaic cell under the standard test condition is calculated according to formula (8) Similarly, the light-generated current of the shadowed area and the non-shadowed area of the back side of a monolithic bifacial photovoltaic cell under the standard test condition is calculated according to the above formula (8)

[0140] Since the light-generated current is proportional to the radiation intensity, the light-generated current of the shadowed area and the non-shadowed area under the shadowed scenario can be calculated according to the radiation shading ratio SR, the light-generated current of the shadowed area and the non-shadowed area under the standard test condition. The light-generated current of the shadowed area and the non-shadowed area of a cell under the shadowed scenario and can be calculated according to SR, and the calculation formula is:

[0141]

[0142] ​The above formula (9) is used to calculate the photo-generated current of the shadow area and the non-shadow area of any side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario. The photo-generated current of the front side shadow area and the non-shadow area of the single-piece bifacial photovoltaic cell under the shadow shielding scenario is calculated respectively with reference to the above formula (9) Similarly, the photo-generated current of the back side shadow area and the non-shadow area of the single-piece bifacial photovoltaic cell under the shadow shielding scenario is calculated respectively with reference to the above formula (9)

[0143] The photo-generated current of the single-piece bifacial photovoltaic cell under the shadow shielding scenario The size is:

[0144]

[0145] The above formula (10) is used to calculate the photo-generated current of any side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario. The photo-generated current of the front side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario is calculated with reference to the above formula (10) and the photo-generated current of the back side under the shadow shielding scenario

[0146] In specific embodiments, the series resistance of the front side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario the series resistance of the back side under the shadow shielding scenario the parallel resistance of the front side under the shadow shielding scenario and the parallel resistance of the back side under the shadow shielding scenario are described.

[0147] Since the resistance of the material is inversely proportional to its cross-sectional area, the series resistance and the parallel resistance of different cell areas can be calculated according to POSA, and the calculation formula is:

[0148]

[0149] The above formula (11) is used to calculate the series resistance of the shadow area and the non-shadow area of any side of the single-piece bifacial photovoltaic cell under the STC working condition. The series resistance of the front side shadow area and the non-shadow area of the single-piece bifacial photovoltaic cell under the standard test condition is calculated respectively with reference to the above formula (11) Similarly, the series resistance of the back side shadow area and the non-shadow area of the single-piece bifacial photovoltaic cell under the standard test condition is calculated respectively with reference to the above formula (11)

[0150] The above formula (12) is used to calculate the parallel resistance of the shaded and non-shaded regions on either side of the single bifacial photovoltaic cell under STC conditions. The parallel resistance of the front-side shaded and non-shaded regions of the single bifacial photovoltaic cell under standard test conditions is calculated respectively with reference to the above formula (12) Similarly, the parallel resistance of the back-side shaded and non-shaded regions of the single bifacial photovoltaic cell under standard test conditions is calculated respectively with reference to the above formula (12)

[0151] According to the SR, the series resistance of different cell regions under the shadow shielding scenario can be calculated by formulas (13)-(14) and the parallel resistance

[0152]

[0153] The above formula (13) is used to calculate the series resistance of the shaded and non-shaded regions on either side of the single bifacial photovoltaic cell under the shadow shielding scenario. The series resistance of the front-side shaded and non-shaded regions of the single bifacial photovoltaic cell under the shadow shielding scenario is calculated respectively with reference to the above formula (13) Similarly, the series resistance of the back-side shaded and non-shaded regions of the single bifacial photovoltaic cell under the shadow shielding scenario is calculated respectively with reference to the above formula (13)

[0154] The above formula (14) is used to calculate the parallel resistance of the shaded and non-shaded regions on either side of the single bifacial photovoltaic cell under the shadow shielding scenario. The parallel resistance of the front-side shaded and non-shaded regions of the single bifacial photovoltaic cell under the shadow shielding scenario is calculated respectively with reference to the above formula (14) Similarly, the parallel resistance of the back-side shaded and non-shaded regions of the single bifacial photovoltaic cell under the shadow shielding scenario is calculated respectively with reference to the above formula (14)

[0155] Based on the double-current source model of the bifacial cell under the shadow shielding scenario, the series resistance and the parallel resistance of the single bifacial photovoltaic cell under the shadow shielding scenario can be calculated by formulas (15)-(16)

[0156]

[0157]

[0158] The above formula (15) is used to calculate the series resistance of any side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario. Referring to the above formula (15), the series resistance of the front side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario is calculated and the series resistance of the back side under the shadow shielding scenario is calculated

[0159] The above formula (16) is used to calculate the parallel resistance of any side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario. Referring to the above formula (16), the parallel resistance of the front side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario is calculated and the parallel resistance of the back side under the shadow shielding scenario is calculated

[0160] In specific embodiments, the thermal voltage and the dark saturation current of the single piece of bifacial photovoltaic cell under the shadow shielding scenario are described.

[0161] Since the thermal voltage and the dark saturation current are not affected by the radiation intensity, but only by the temperature, the thermal voltage and the dark saturation current of the cell under the shadow shielding scenario remain the same as under the condition of uniform distribution of radiation, and their sizes are calculated as formulas (17)-(18):

[0162]

[0163] The above formula (17) is used to calculate the thermal voltage of any side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario. Referring to the above formula (17), the thermal voltage of the front side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario is calculated and the thermal voltage of the back side under the shadow shielding scenario is calculated

[0164] The above formula (18) is used to calculate the dark saturation current of any side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario. Referring to the above formula (18), the dark saturation current of the front side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario is calculated and the dark saturation current of the back side under the shadow shielding scenario is calculated

[0165] Through the above steps, the five parameters of the front side of the single piece of bifacial photovoltaic cell under the shadow shielding scenario and and the five parameters of the back side under the shadow shielding scenario and can be calculated respectively.

[0166] S304: calculating the target five parameters of the single-bifacial photovoltaic cell under the shadow blocking scenario according to the pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell, and the five parameters of the front / back side of the single-bifacial photovoltaic cell under the shadow blocking scenario.

[0167] The front side and the back side of the single-bifacial photovoltaic cell may both appear Figure 5 the shadow blocking scenario. In the pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell, the target five parameters of the single-bifacial photovoltaic cell under the shadow blocking scenario are calculated based on the aforementioned five parameters of the front side under the shadow blocking scenario and the five parameters of the back side under the shadow blocking scenario.

[0168] The total photo-generated current of the single-bifacial photovoltaic cell is equal to the sum of the front side photo-generated current and the back side photo-generated current, and the front side open circuit voltage is approximately equal to the back side open circuit voltage, so it can be assumed that the front side and the back side of the single-bifacial photovoltaic cell are in parallel, and the parallel model can be referred to as Figure 7 . The left dashed box represents the front side of the single-bifacial photovoltaic cell, and the right dashed box represents the back side of the single-bifacial photovoltaic cell. The series resistance of the front side and the back side is located on the main circuit of the parallel circuit.

[0169] The front side and the back side circuit in the parallel model shown in Figure 7 can be combined to obtain Figure 8 the parallel equivalent circuit model shown in, that is, the parallel equivalent circuit model of the bifacial photovoltaic cell. The parallel equivalent circuit model of the bifacial photovoltaic cell is used to calculate the target five parameters of the single-bifacial photovoltaic cell under the shadow blocking scenario. Among them, the first dashed box from left to right represents the combined target photo-generated current the second dashed box represents the combined target parallel resistance the third dashed box represents the combined target series resistance

[0170] and and

[0171]

[0172] Since the thermal voltage and the dark saturation current are only affected by temperature, and the front side and the back side of the bifacial photovoltaic module have the same temperature, the combined target dark saturation current and the target thermal voltage are approximately equal to the values of the front side of the module:

[0173]

[0174] According to the parallel circuit characteristics between the shadow area and the non-shadow area, the target five parameters of the single bifacial photovoltaic cell under the shadow shading scenario can be calculated by the foregoing formulas (19)-(23) and ).

[0175] The foregoing implementation of the electrical sub-model 1 (the double-current source model of the bifacial photovoltaic cell under the shadow shading scenario) and the electrical sub-model 2 (the parallel equivalent circuit model of the bifacial photovoltaic cell) is described, and on this basis, the composite electrical model as shown in Figure 9 is established. The composite electrical model can accurately evaluate the dynamic output power of the bifacial photovoltaic cell under the complex shadow shading scenario, that is, the model not only considers the bifacial power generation characteristics of the bifacial photovoltaic module, but also effectively processes the power generation characteristics of the front / back side of the bifacial photovoltaic module under the complex shadow shading scenario.

[0176] Referring to Figure 10 , Figure 10 , a target five parameter calculation flowchart provided by the embodiment of the present application is provided.

[0177] The photo-generated current parallel resistance and series resistance of the front side of the single bifacial photovoltaic cell under the shadow shading scenario can be calculated by the electrical sub-model 1, and the five parameters and of the front side of the single bifacial photovoltaic cell under the shadow shading scenario are further calculated. Similarly, the five parameters and of the back side of the single bifacial photovoltaic cell under the shadow shading scenario are calculated by the electrical sub-model 1.

[0178] On the basis of the five parameters of the front side of the single bifacial photovoltaic cell under the shadow shading scenario and the five parameters of the back side of the single bifacial photovoltaic cell under the shadow shading scenario, the overall five parameters and of the front / back side of the single bifacial photovoltaic cell under the shadow shading scenario, that is, the target five parameters, can be calculated by the electrical sub-model 2.

[0179] S305: Based on the target five parameters of the single bifacial photovoltaic cell under the shadow shading scenario, the I-V characteristic equation of the single bifacial photovoltaic cell, the bifacial photovoltaic cell string, and the bifacial photovoltaic module is calculated in sequence to determine the output power of the bifacial photovoltaic module under the shadow shading scenario.

[0180] In order to calculate the total output power of each single bifacial photovoltaic cell in the entire bifacial photovoltaic module under different front / back side shadow blocking scenarios, based on the five parameters of the single bifacial photovoltaic cell under the front / back side shadow blocking scenario, the I-V characteristic equation of the single bifacial photovoltaic cell, the I-V characteristic equation of the bifacial photovoltaic cell string and the I-V characteristic equation of the bifacial photovoltaic module are sequentially calculated.

[0181] In a possible implementation manner, the I-V characteristic equations of the single bifacial photovoltaic cell, the bifacial photovoltaic cell string and the bifacial photovoltaic module are sequentially calculated based on the target five parameters of the single bifacial photovoltaic cell under the shadow blocking scenario, and the output power of the bifacial photovoltaic module under the shadow blocking scenario is determined, including: the I-V characteristic equation of the single bifacial photovoltaic cell under the shadow blocking scenario is calculated by using the target five parameters of the single bifacial photovoltaic cell under the shadow blocking scenario; the I-V characteristic equation of the bifacial photovoltaic cell string under the shadow blocking scenario is calculated based on the I-V characteristic equation of the single bifacial photovoltaic cell; the I-V characteristic equation of the bifacial photovoltaic module under the shadow blocking scenario is calculated based on the I-V characteristic equation of the bifacial photovoltaic cell string; and the output power of the bifacial photovoltaic module under the shadow blocking scenario is determined based on the I-V characteristic equation of the bifacial photovoltaic module.

[0182] In specific embodiments, the determination process of the I-V characteristic equation of the single bifacial photovoltaic cell is described as follows.

[0183] According to the output current I of the bifacial photovoltaic module and the photo-generated current J of the single bifacial photovoltaic cell The bifacial photovoltaic cell can be divided into two working states according to whether the cell can normally output power, and the I-V characteristic equation of each cell is calculated.

[0184] When the output current I of the bifacial photovoltaic module is less than the photo-generated current J of the single bifacial photovoltaic cell , the single bifacial photovoltaic cell in the bifacial photovoltaic cell string can normally output power; when the output current I of the bifacial photovoltaic module is greater than or equal to the photo-generated current J of the single bifacial photovoltaic cell , the bifacial photovoltaic cell is reversely biased and consumes power, resulting in a negative terminal voltage of the bifacial photovoltaic cell, and therefore, the I-V characteristic equation of the single bifacial photovoltaic cell is:

[0185]

[0186] wherein q represents the qth single bifacial photovoltaic cell in the bifacial photovoltaic cell string, LambertW is a Lambert W function,

[0187] In specific embodiments, the following describes the determination process of the I-V characteristic equation of the bifacial photovoltaic cell string and the I-V characteristic equation of the bifacial photovoltaic module.

[0188] The voltages of the individual bifacial photovoltaic cells in the bifacial photovoltaic cell string are added up while keeping the current the same; it is determined whether the bypass diode of the bifacial photovoltaic cell string is turned on, thereby calculating the I-V characteristic equation of the bifacial photovoltaic cell string. When the terminal voltage V str of the bifacial photovoltaic cell string is negative and reaches the turn-on voltage -V bd of the bypass diode, the bypass diode of the bifacial photovoltaic cell string will be in the turned-on state. Due to the "clamping" effect of the bypass diode, the terminal voltage of the bifacial photovoltaic cell string will remain unchanged at -V bd . Therefore, the I-V characteristic equation of the bifacial photovoltaic cell string is:

[0189]

[0190] Since the bifacial photovoltaic cell strings are connected in series with each other, the voltages of the bifacial photovoltaic cell strings can be added up to calculate the total voltage V of the module while keeping the current the same: pv

[0191]

[0192] The power of the bifacial photovoltaic module can be determined according to the I-V characteristic equation of the output current and the output voltage of the bifacial photovoltaic module.

[0193] Referring to Figure 11 , Figure 11 FIG. 8 is another flowchart of a method for evaluating the output power of a bifacial photovoltaic module in a shadow shielding scenario according to an embodiment of the present application. The five parameters of the front side and the back side of the bifacial photovoltaic module in the STC working condition are calculated through the front side rated parameters and the back side rated parameters and the I-V characteristic equation of the bifacial photovoltaic module. The five parameters of the front side and the back side of the single bifacial photovoltaic cell in the STC working condition are calculated according to the internal circuit characteristics of the photovoltaic module. The five parameters of the front side and the back side of the single bifacial photovoltaic cell in the shadow shielding scenario are calculated through the POSA and the SA. The double-current source model of the bifacial photovoltaic cell in the shadow shielding scenario is constructed, and the five parameters of the front side and the back side of the single bifacial photovoltaic cell in the shadow shielding scenario are calculated.

[0194] ​A double-sided photovoltaic cell parallel equivalent circuit model is constructed, the model represents the dynamic power generation performance of the front / back side of the double-sided photovoltaic cell through five parameters of the front / back side, according to the parallel circuit characteristics between the front side and the back side of the single double-sided photovoltaic cell, the target five parameters of the single double-sided photovoltaic cell under the shadow shielding scene are calculated, and the I-V characteristic equation of the single double-sided photovoltaic cell, the cell string and the module is calculated in turn based on this, and finally the accurate evaluation of the output power of the double-sided photovoltaic module under the complex shadow shielding scene is realized.

[0195] Based on Figure 11 The specific steps can know that the double current source model (electrical submodel 1) of the double-sided photovoltaic cell under the shadow shielding scene proposed in the embodiment of the application can consider the electrical mismatch between the shadow area and the non-shadow area of the single double-sided photovoltaic cell, thereby improving the accuracy of the simulation result of the power of the module under the shadow shielding scene of the cell; in view of the simulation error problem caused by simulating the dynamic output power of the double-sided photovoltaic module by using the constant double-sided coefficient, the parallel equivalent circuit model (electrical submodel 2) of the double-sided photovoltaic cell is proposed in the embodiment of the application, the model can represent the dynamic electrical performance of the front / back side of the cell through five parameters of the front / back side, and according to the parallel circuit characteristics between the front side and the back side of the cell, the five parameters of the whole single double-sided photovoltaic cell are calculated, which can further accurately calculate the output power of the double-sided photovoltaic module and improve the accuracy of the simulation. The composite electrical model proposed on the basis of the two aforementioned electrical submodels calculates the target five parameters of the single double-sided photovoltaic cell under the complex shadow shielding scene, and calculates the I-V characteristic equation of the cell, the cell string and the module in turn based on this, which can accurately evaluate the dynamic output power of the double-sided photovoltaic module under the complex front / back side shadow shielding scene. When simulating the output power of the double-sided photovoltaic module, the composite electrical model not only improves the accuracy, but also adapts to the complex front / back side local shadow shielding scene, and has a more extensive application scenario.

[0196] The foregoing embodiment of the application provides a method for evaluating the output power of a double-sided photovoltaic module under a shadow shielding scene. Next, an evaluation device for the output power of a double-sided photovoltaic module under a shadow shielding scene is described, which is used to execute the method shown in the foregoing Figure 3 Next, the function of the evaluation device for the output power of a double-sided photovoltaic module under a shadow shielding scene is described. The structure diagram of the evaluation device for the output power of a double-sided photovoltaic module under a shadow shielding scene is shown in Figure 12 The evaluation device for the output power of a double-sided photovoltaic module under a shadow shielding scene includes a first calculation module 1201, a first determination module 1202, a second calculation module 1203, a third calculation module 1204 and a second determination module 1205.

[0197] The double-sided photovoltaic module is connected by a plurality of single double-sided photovoltaic cells, wherein:

[0198] The first calculation module 1201 is configured to calculate five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under standard test conditions, the five parameters including a photo-generated current, a dark saturation current of a diode, a series resistance, a parallel resistance and a diode thermal voltage.

[0199] The first determination module 1202 is configured to determine a shadow area percentage and a radiation shielding ratio of the single-piece bifacial photovoltaic cell, the shadow area percentage and the radiation shielding ratio being used to represent a shadow shielding condition of the single-piece bifacial photovoltaic cell.

[0200] The second calculation module 1203 is configured to calculate five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under a shadow shielding scenario according to a pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under the standard test conditions, the shadow area percentage and the radiation shielding ratio.

[0201] The third calculation module 1204 is configured to calculate target five parameters of the single-piece bifacial photovoltaic cell under the shadow shielding scenario according to a pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell and the five parameters of the front side and the back side of the single-piece bifacial photovoltaic cell under the shadow shielding scenario.

[0202] The second determination module 1205 is configured to sequentially calculate I-V characteristic equations of the single-piece bifacial photovoltaic cell, a bifacial photovoltaic cell string and a bifacial photovoltaic module based on the target five parameters of the single-piece bifacial photovoltaic cell under the shadow shielding scenario, and determine output power of the bifacial photovoltaic module under the shadow shielding scenario.

[0203] In a possible implementation manner, the first calculation module 1201 is specifically configured to:

[0204] obtain front side rated parameters, back side rated parameters and internal circuit characteristics of the bifacial photovoltaic module;

[0205] calculate five parameters of the front side of the bifacial photovoltaic module under the standard test conditions by using a preset I-V characteristic equation and the front side rated parameters;

[0206] calculate five parameters of the back side of the bifacial photovoltaic module under the standard test conditions by using a preset I-V characteristic equation and the back side rated parameters;

[0207] calculate the five parameters of the front side of the single-piece bifacial photovoltaic cell under the standard test conditions based on the five parameters of the front side of the bifacial photovoltaic module under the standard test conditions and the internal circuit characteristics of the bifacial photovoltaic module;

[0208] The five parameters of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario are calculated based on the five parameters of the front side of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario and the five parameters of the front side of the single piece of the bifacial photovoltaic cell under the standard test condition.

[0209] In a possible implementation, the first determining module 1202 is specifically configured to:

[0210] The shadow area percentage is determined based on the shadow area and the non-shadow area.

[0211] In a possible implementation, the second calculating module 1203 is specifically configured to:

[0212] The five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the rear side shadow area, and the five parameters of the rear side non-shadow area of the single piece of the bifacial photovoltaic cell under the standard test condition are respectively calculated based on the shadow area percentage and the five parameters of the front / rear side of the single piece of the bifacial photovoltaic cell under the standard test condition.

[0213] The five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the rear side shadow area, and the five parameters of the rear side non-shadow area of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario are calculated based on the radiation blocking ratio, the five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the rear side shadow area, and the five parameters of the rear side non-shadow area of the single piece of the bifacial photovoltaic cell under the standard test condition.

[0214] In the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow blocking scenario, the five parameters of the front side of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario are calculated based on the five parameters of the front side shadow area of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario and the five parameters of the front side non-shadow area of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario.

[0215] In the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow blocking scenario, the five parameters of the rear side of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario are calculated based on the five parameters of the rear side shadow area of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario and the five parameters of the rear side non-shadow area of the single piece of the bifacial photovoltaic cell under the shadow blocking scenario.

[0216] In a possible implementation, the second determining module 1205 is specifically configured to:

[0217] The I-V characteristic equation of the double-sided photovoltaic cell string under the shadow shielding scene is calculated based on the I-V characteristic equation of the single double-sided photovoltaic cell.

[0218] The I-V characteristic equation of the double-sided photovoltaic cell string under the shadow shielding scene is calculated based on the I-V characteristic equation of the single double-sided photovoltaic cell.

[0219] The I-V characteristic equation of the double-sided photovoltaic cell string under the shadow shielding scene is calculated based on the I-V characteristic equation of the single double-sided photovoltaic cell.

[0220] The I-V characteristic equation of the double-sided photovoltaic cell string under the shadow shielding scene is calculated based on the I-V characteristic equation of the single double-sided photovoltaic cell.

[0221] The I-V characteristic equation of the double-sided photovoltaic cell string under the shadow shielding scene is calculated based on the I-V characteristic equation of the single double-sided photovoltaic cell. The application embodiment provides an evaluation device for output power of a double-sided photovoltaic module under a shadow shielding scene, which comprises a first calculation module, a first determination module, a second calculation module, a third calculation module and a second determination module. The double-sided photovoltaic module is connected by a plurality of single double-sided photovoltaic cells. The first calculation module is used for calculating five parameters of the front and back sides of the single double-sided photovoltaic cell under standard test conditions. The first determination module is used for determining a shadow area percentage and a radiation shielding ratio of the single double-sided photovoltaic cell, which are used for representing the shadow shielding condition of the single double-sided photovoltaic cell. The second calculation module is used for calculating five parameters of the front and back sides of the single double-sided photovoltaic cell under the shadow shielding scene according to a double-current source model of the double-sided photovoltaic cell under the shadow shielding scene, the five parameters of the front and back sides of the single double-sided photovoltaic cell under the standard test conditions, the shadow area percentage and the radiation shielding ratio. The third calculation module is used for calculating target five parameters of the single double-sided photovoltaic cell under the shadow shielding scene according to a parallel equivalent circuit model of the double-sided photovoltaic cell and the five parameters of the front and back sides of the single double-sided photovoltaic cell under the shadow shielding scene. The second determination module is used for sequentially calculating I-V characteristic equations of the single double-sided photovoltaic cell, the double-sided photovoltaic cell string and the double-sided photovoltaic module based on the target five parameters of the single double-sided photovoltaic cell under the shadow shielding scene, and determining the output power of the double-sided photovoltaic module under the shadow shielding scene.

[0222] Thus, a double current source of the bifacial photovoltaic cell under the shadow shielding scene is constructed, five parameters of the front side of the single bifacial photovoltaic cell under the shadow shielding scene and five parameters of the back side of the single bifacial photovoltaic cell under the shadow shielding scene are calculated respectively, and the electrical mismatch problem existing between the shadow area and the non-shadow area of the cell can be considered; a parallel equivalent circuit model of the bifacial photovoltaic cell considering the dynamic power generation characteristics of the front / back side of the bifacial photovoltaic cell is constructed, and is used to calculate the five parameters of the front / back side of the single bifacial photovoltaic cell. The composite electrical model is established by combining the two sub-models, the target five parameters of the bifacial photovoltaic cell under the complex shadow shielding scene are calculated, and the I-V characteristic equation of the cell, the cell string and the module is calculated in sequence based on the target five parameters, so that the dynamic output power of the bifacial photovoltaic module under the complex front / back side shadow shielding scene can be accurately evaluated.

[0223] Based on the method embodiment provided above, the embodiment of the present application provides an evaluation method of output power of a bifacial photovoltaic module under a shadow shielding scene, and the evaluation method is as shown in Figure 13 , the device comprises a processor, a memory and a system bus.

[0224] The processor and the memory are connected through the system bus.

[0225] The memory is used to store one or more programs, and the one or more programs comprise instructions, which, when executed by the processor, cause the processor to execute the evaluation method of output power of a bifacial photovoltaic module under a shadow shielding scene according to any one of the above embodiments.

[0226] Based on the method embodiment provided above, the embodiment of the present application provides a computer readable storage medium, which stores instructions, and when the instructions run on a device, the device executes the evaluation method of output power of a bifacial photovoltaic module under a shadow shielding scene according to any one of the above embodiments.

[0227] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and apparatus embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0228] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0229] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for evaluating output power of a bifacial photovoltaic module under shadowing shading scenarios, characterized in that, The bifacial photovoltaic module is connected by a plurality of single bifacial photovoltaic cells, and the evaluation method comprises the following steps: Calculate five parameters of the front / rear side of the single bifacial photovoltaic cell under standard test conditions, wherein the five parameters include photo-generated current, dark saturation current of a diode, series resistance, parallel resistance and diode thermal voltage; Determine the shadow area percentage and the radiation shielding ratio of the single bifacial photovoltaic cell, wherein the shadow area percentage and the radiation shielding ratio are used to represent the shadow shielding condition of the single bifacial photovoltaic cell; According to the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scene, the five parameters of the front / rear side of the single bifacial photovoltaic cell under the standard test conditions, the shadow area percentage and the radiation shielding ratio, calculate the five parameters of the front / rear side of the single bifacial photovoltaic cell under the shadow shielding scene; According to the pre-constructed parallel equivalent circuit model of the bifacial photovoltaic cell and the five parameters of the front / rear side of the single bifacial photovoltaic cell under the shadow shielding scene, calculate the target five parameters of the single bifacial photovoltaic cell under the shadow shielding scene; Based on the target five parameters of the single bifacial photovoltaic cell under the shadow shielding scene, sequentially calculate the I-V characteristic equation of the single bifacial photovoltaic cell, the bifacial photovoltaic cell string and the bifacial photovoltaic module, and determine the output power of the bifacial photovoltaic module under the shadow shielding scene.

2. The evaluation method according to claim 1, characterized in that The calculation of the five parameters of the front / rear side of the single bifacial photovoltaic cell under the standard test conditions comprises the following steps: Obtain the front side rated parameter, the rear side rated parameter and the internal circuit characteristics of the bifacial photovoltaic module; Calculate the five parameters of the front side of the bifacial photovoltaic module under the standard test conditions by using the preset I-V characteristic equation and the front side rated parameter; Calculate the five parameters of the rear side of the bifacial photovoltaic module under the standard test conditions by using the preset I-V characteristic equation and the rear side rated parameter; Based on the five parameters of the front side of the bifacial photovoltaic module under the standard test conditions and the internal circuit characteristics of the bifacial photovoltaic module, calculate the five parameters of the front side of the single bifacial photovoltaic cell under the standard test conditions; Based on the five parameters of the rear side of the bifacial photovoltaic module under the standard test conditions and the internal circuit characteristics of the bifacial photovoltaic module, calculate the five parameters of the rear side of the single bifacial photovoltaic cell under the standard test conditions.

3. The evaluation method according to claim 1, characterized in that The determination of the shadow area percentage and the radiation shielding ratio of the single bifacial photovoltaic cell comprises the following steps: Obtain the shadow area, the shadow area radiation intensity, the non-shadow area and the non-shadow area radiation intensity of the single bifacial photovoltaic cell under the shadow shielding scene; Determine the shadow area percentage based on the shadow area and the non-shadow area; Determine the radiation shielding ratio based on the shadow area radiation intensity and the non-shadow area radiation intensity.

4. The evaluation method according to claim 3, characterized in that The calculation of the five parameters of the front / rear side of the single bifacial photovoltaic cell under the shadow shielding scene according to the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scene, the five parameters of the front / rear side of the single bifacial photovoltaic cell under the standard test conditions, the shadow area percentage and the radiation shielding ratio comprises the following steps: According to the shadow area percentage and the five parameters of the front / rear side of the single piece bifacial photovoltaic cell under standard test conditions, the front side shadow area five parameters, the front side non-shadow area five parameters, the rear side shadow area five parameters and the rear side non-shadow area five parameters of the single piece bifacial photovoltaic cell under standard test conditions are calculated respectively; According to the radiation shielding ratio, the front side shadow area five parameters, the front side non-shadow area five parameters, the rear side shadow area five parameters and the rear side non-shadow area five parameters of the single piece bifacial photovoltaic cell under standard test conditions, the front side shadow area five parameters, the front side non-shadow area five parameters, the rear side shadow area five parameters and the rear side non-shadow area five parameters of the single piece bifacial photovoltaic cell under shadow shielding scenario are calculated; In the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scenario, based on the front side shadow area five parameters of the single piece bifacial photovoltaic cell under the shadow shielding scenario and the front side non-shadow area five parameters of the single piece bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the front side of the single piece bifacial photovoltaic cell under the shadow shielding scenario are calculated; In the pre-constructed double-current source model of the bifacial photovoltaic cell under the shadow shielding scenario, based on the rear side shadow area five parameters of the single piece bifacial photovoltaic cell under the shadow shielding scenario and the rear side non-shadow area five parameters of the single piece bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the rear side of the single piece bifacial photovoltaic cell under the shadow shielding scenario are calculated.

5. The evaluation method according to claim 1, characterized in that The target five parameters of the single piece bifacial photovoltaic cell under the shadow shielding scenario are used to calculate the I-V characteristic equation of the single piece bifacial photovoltaic cell under the shadow shielding scenario, the I-V characteristic equation of the bifacial photovoltaic cell string under the shadow shielding scenario, the I-V characteristic equation of the bifacial photovoltaic module under the shadow shielding scenario, and the output power of the bifacial photovoltaic module under the shadow shielding scenario, including: The target five parameters of the single piece bifacial photovoltaic cell under the shadow shielding scenario are used to calculate the I-V characteristic equation of the single piece bifacial photovoltaic cell under the shadow shielding scenario; Based on the I-V characteristic equation of the single piece bifacial photovoltaic cell, the I-V characteristic equation of the bifacial photovoltaic cell string under the shadow shielding scenario is calculated; Based on the I-V characteristic equation of the bifacial photovoltaic cell string, the I-V characteristic equation of the bifacial photovoltaic module under the shadow shielding scenario is calculated; Based on the I-V characteristic equation of the bifacial photovoltaic module, the output power of the bifacial photovoltaic module under the shadow shielding scenario is determined.

6. A device for evaluating the output power of a bifacial photovoltaic module under shading conditions, characterized in that, The bifacial photovoltaic module is connected by a plurality of single piece bifacial photovoltaic cells, and the evaluation device comprises: A first calculation module is configured to calculate the five parameters of the front / rear side of the single piece bifacial photovoltaic cell under standard test conditions, including photo-generated current, diode dark saturation current, series resistance, parallel resistance and diode thermal voltage; A first determination module is configured to determine the shadow area percentage and the radiation shielding ratio of the single piece bifacial photovoltaic cell, which are used to represent the shadow shielding condition of the single piece bifacial photovoltaic cell; The second calculation module is configured to calculate five parameters of the front side and the rear side of the single-piece bifacial photovoltaic cell in the shadow shielding scenario according to a double-current source model of the bifacial photovoltaic cell in the shadow shielding scenario, five parameters of the front side and the rear side of the single-piece bifacial photovoltaic cell in the standard test condition, the shadow area percentage, and the radiation shielding ratio. The third calculation module is configured to calculate target five parameters of the single-piece bifacial photovoltaic cell in the shadow shielding scenario according to a parallel equivalent circuit model of the bifacial photovoltaic cell and the five parameters of the front side and the rear side of the single-piece bifacial photovoltaic cell in the shadow shielding scenario. The second determination module is configured to sequentially calculate I-V characteristic equations of the single-piece bifacial photovoltaic cell, the bifacial photovoltaic cell string, and the bifacial photovoltaic module based on the target five parameters of the single-piece bifacial photovoltaic cell in the shadow shielding scenario, and determine output power of the bifacial photovoltaic module in the shadow shielding scenario.

7. The evaluation device according to claim 6, characterized in that The first calculation module is specifically configured to: obtain front side rated parameters, rear side rated parameters, and internal circuit characteristics of the bifacial photovoltaic module; calculate five parameters of the front side of the bifacial photovoltaic module in the standard test condition by using a preset I-V characteristic equation and the front side rated parameters; calculate five parameters of the rear side of the bifacial photovoltaic module in the standard test condition by using the preset I-V characteristic equation and the rear side rated parameters; calculate five parameters of the front side of the single-piece bifacial photovoltaic cell in the standard test condition based on the five parameters of the front side of the bifacial photovoltaic module in the standard test condition and the internal circuit characteristics of the bifacial photovoltaic module; calculate five parameters of the rear side of the single-piece bifacial photovoltaic cell in the standard test condition based on the five parameters of the rear side of the bifacial photovoltaic module in the standard test condition and the internal circuit characteristics of the bifacial photovoltaic module.

8. The evaluation device according to claim 6, characterized in that The first determination module is specifically configured to: obtain a shadow area, a shadow area radiation intensity, a non-shadow area, and a non-shadow area radiation intensity of the single-piece bifacial photovoltaic cell in the shadow shielding scenario; determine the shadow area percentage based on the shadow area and the non-shadow area; determine the radiation shielding ratio based on the shadow area radiation intensity and the non-shadow area radiation intensity.

9. The evaluation device according to claim 8, characterized in that The second calculation module is specifically configured to: calculate five parameters of a front side shadow area, five parameters of a front side non-shadow area, five parameters of a rear side shadow area, and five parameters of a rear side non-shadow area of the single-piece bifacial photovoltaic cell in the standard test condition based on the shadow area percentage and the five parameters of the front side and the rear side of the single-piece bifacial photovoltaic cell in the standard test condition; calculate five parameters of a front side shadow area, five parameters of a front side non-shadow area, five parameters of a rear side shadow area, and five parameters of a rear side non-shadow area of the single-piece bifacial photovoltaic cell in the shadow shielding scenario based on the radiation shielding ratio, the five parameters of the front side shadow area, the five parameters of the front side non-shadow area, the five parameters of the rear side shadow area, and the five parameters of the rear side non-shadow area of the single-piece bifacial photovoltaic cell in the standard test condition. In the double-current-source model of the pre-constructed bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the single-piece bifacial photovoltaic cell front side under the shadow shielding scenario are calculated based on the five parameters of the single-piece bifacial photovoltaic cell front side shadow area under the shadow shielding scenario and the five parameters of the single-piece bifacial photovoltaic cell front side non-shadow area under the shadow shielding scenario. In the double-current-source model of the pre-constructed bifacial photovoltaic cell under the shadow shielding scenario, the five parameters of the single-piece bifacial photovoltaic cell back side under the shadow shielding scenario are calculated based on the five parameters of the single-piece bifacial photovoltaic cell back side shadow area under the shadow shielding scenario and the five parameters of the single-piece bifacial photovoltaic cell back side non-shadow area under the shadow shielding scenario.

10. The evaluation device according to claim 6, characterized in that The second determination module is specifically configured to: The target five parameters of the single-piece bifacial photovoltaic cell under the shadow shielding scenario are used to calculate the I-V characteristic equation of the single-piece bifacial photovoltaic cell under the shadow shielding scenario; Based on the I-V characteristic equation of the single-piece bifacial photovoltaic cell, the I-V characteristic equation of the bifacial photovoltaic cell string under the shadow shielding scenario is calculated; Based on the I-V characteristic equation of the bifacial photovoltaic cell string, the I-V characteristic equation of the bifacial photovoltaic module under the shadow shielding scenario is calculated; Based on the I-V characteristic equation of the bifacial photovoltaic module, the output power of the bifacial photovoltaic module under the shadow shielding scenario is determined.

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