A method and device for testing solar cells

Abstract

The present application discloses a method and device for testing solar cells, belonging to the field of solar cells. The method for testing solar cells provided by the present application includes: obtaining test data of the solar cell, the test data including external quantum efficiency, surface reflectivity and spectral transmittance; determining the external spectral recombination rate of the solar cell based on the external quantum efficiency, surface reflectivity and spectral transmittance; the external spectral recombination rate is the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination; determining the recombination loss current of the solar cell based on the external spectral recombination rate; the recombination loss current is used to quantitatively characterize the recombination loss of the solar cell. The present application is used to test the recombination loss of a solar cell.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a method and device for testing solar cells. Background Art

[0002] During the trial production of solar cells, it is very important to test the recombination loss of solar cells with different materials and thicknesses, and then optimize and adjust the material ratio and thickness of the solar cells based on the recombination loss.

[0003] In related technologies, the internal quantum efficiency of solar cells is generally tested. The internal quantum efficiency can be understood as the ratio of the average number of photoelectrons generated by the solar cell per unit time at a specific wavelength to the number of photons incident on the solar cell. The internal quantum efficiency can then be used to measure the recombination loss of the solar cell.

[0004] However, because the internal quantum efficiency test does not exclude photons that pass through the solar cell and are not utilized, it is easy to misjudge the problem, resulting in poor accuracy in measuring the recombination loss of the solar cell. For example, when the internal quantum efficiency is low, it may be due to excessive recombination losses within the solar cell or a large number of photons passing through the cell. In this case, using the internal quantum efficiency to measure recombination loss can easily lead to poor accuracy in the recombination loss test. Summary of the Invention

[0005] The embodiments of the present application provide a method and device for testing solar cells, which can solve the problem of poor accuracy in testing recombination loss of solar cells in the related art.

[0006] In a first aspect, an embodiment of the present application provides a method for testing a solar cell, comprising:

[0007] Obtain test data of solar cells, including external quantum efficiency, surface reflectivity, and spectral transmittance;

[0008] Based on the external quantum efficiency, surface reflectivity and spectral transmittance, the external spectral recombination rate of the solar cell is determined. The external spectral recombination rate is the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination.

[0009] Based on the external spectrum recombination rate, the recombination loss current of the solar cell is determined; the recombination loss current is used to quantitatively characterize the recombination loss of the solar cell.

[0010] In a second aspect, an embodiment of the present application provides a testing device, comprising a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the method described in the first aspect is implemented.

[0011] In an embodiment of the present application, test data of a solar cell is obtained, the test data including external quantum efficiency, surface reflectivity and spectral transmittance; based on the external quantum efficiency, surface reflectivity and spectral transmittance, the external spectral recombination rate of the solar cell is determined; wherein the external spectral recombination rate is the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination; since the external spectral recombination rate focuses on the part of photons that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination, the influence of photons that are transmitted through the solar cell but not utilized is excluded, and then the recombination loss current of the solar cell is determined based on the external spectral recombination rate, and the recombination loss current is used to quantify the recombination loss of the solar cell, thereby improving the accuracy of the test recombination loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 A schematic flow chart of a solar cell testing method provided in an embodiment of the present application;

[0014] Figure 2 A schematic flow chart of another solar cell testing method provided in an embodiment of the present application;

[0015] Figure 3 A schematic flow chart of another solar cell testing method provided in an embodiment of the present application;

[0016] Figure 4 A schematic flow chart of another solar cell testing method provided in an embodiment of the present application;

[0017] Figure 5 A schematic flow chart of another solar cell testing method provided in an embodiment of the present application;

[0018] Figure 6 A schematic flow chart of another solar cell testing method provided in an embodiment of the present application;

[0019] Figure 7 A schematic structural diagram of a test device provided in an embodiment of the present application;

[0020] Figure 8 A schematic structural diagram of a solar cell testing system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] The terms "first", "second", "third", "fourth", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", "third", "fourth", etc. are generally of the same type, and do not limit the number of objects. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0024] In the field of solar cells, quantum efficiency (QE) can be understood as the ratio of the average number of photoelectrons generated per unit time at the target wavelength to the number of incident photons. Among them, quantum efficiency can include external quantum efficiency (EQE) and internal quantum efficiency (IQE). The external quantum efficiency focuses on all photons incident on the solar cell, including photons reflected by the surface of the solar cell; while the internal quantum efficiency focuses on the photons incident on the inside of the solar cell, excluding photons reflected from the surface of the solar cell, and better reflects the utilization of photons inside the solar cell. In other words, the external quantum efficiency can be understood as the ratio of the average number of photoelectrons generated per unit time at the target wavelength to the number of all photons incident on the solar cell, and the internal quantum efficiency can be understood as the ratio of the average number of photoelectrons generated per unit time at the target wavelength to the number of all photons incident on the solar cell.

[0025] As described in the background, related technologies use internal quantum efficiency (IQE) to measure the recombination loss of solar cells. Because IQE testing doesn't exclude unused photons that escape the solar cell's interior, misjudgment can easily occur, leading to poor accuracy in measuring recombination loss.

[0026] Based on this, in order to improve the accuracy of testing the recombination loss of solar cells, the solar cell testing method provided in the embodiment of the present application can test the external quantum efficiency, surface reflectivity and spectral transmittance of the solar cell, calculate the external spectral recombination rate of the solar cell based on the external quantum efficiency, surface reflectivity and spectral transmittance, calculate the recombination loss current based on the external spectral recombination rate of the solar cell, and use the recombination loss current to measure the recombination loss. Since the photons that are transmitted through the cell and not utilized are excluded in the process of calculating the recombination loss current, the accuracy of testing the recombination loss is improved. In addition, the embodiment of the present application can also use the size of the recombination loss current to quantitatively characterize the recombination loss of the solar cell, providing an important data basis for the optimization and improvement of solar cell materials and processes.

[0027] In practical applications, the solar cell testing method provided in the embodiments of the present application can be applied to the optimization and improvement of solar cell materials and processes, or other application scenarios, and the present application does not limit this.

[0028] The following describes the test system provided in the embodiment of the present application in detail through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0029] Figure 1A schematic flow chart of a solar cell testing method provided in an embodiment of the present application.

[0030] like Figure 1 As shown, a solar cell testing method provided by an embodiment of the present application may include:

[0031] Step 110: Acquire test data of the solar cell, the test data including external quantum efficiency, surface reflectivity, and spectral transmittance;

[0032] Step 120: determining the external spectral recombination rate of the solar cell based on the external quantum efficiency, the surface reflectivity, and the spectral transmittance;

[0033] Among them, the external spectrum recombination rate is the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination;

[0034] Step 130: Determine the recombination loss current of the solar cell based on the external spectrum recombination rate; the recombination loss current is used to quantitatively characterize the recombination loss of the solar cell.

[0035] In the embodiment of the present application, the operation process of the solar cell may include four processes: absorption of photons, photogenerated carriers, charge transfer, and charge collection. For example, after incident light irradiates the solar cell, the solar cell may absorb the photon energy through processes such as intrinsic absorption, extrinsic absorption, or free carrier absorption; after absorbing the energy of the photon, electron-hole pairs may be generated; some of the electron-hole pairs may undergo carrier recombination and be offset, while the other electron-hole pairs may be decomposed into electrons and holes by the electric field inside the solar cell, and then driven by the electric field to the electrodes at both ends of the solar cell; when the electrons or holes reach the metal-semiconductor junction near the electrode, they are transferred to the external electrode and generate a short-circuit current under the short-circuit condition of the solar cell.

[0036] It can be understood that in the embodiment of the present application, the incident light entering the solar cell is divided into four parts, among which a part of the photons is reflected by the surface of the solar cell, a part of the photons is transmitted from the inside of the solar cell, a part of the photons is absorbed by the inside of the solar cell to generate electron-hole pairs and then carrier recombination occurs and is lost, and another part of the photons is absorbed by the inside of the solar cell to generate electron-hole pairs and then transmitted to the external electrode to generate short-circuit current.

[0037] In the embodiment of the present application, the surface reflectivity (Reflectivity, R) can be understood as the proportion of all photons incident on the solar cell that are reflected by the surface of the solar cell.

[0038] In the embodiment of the present application, spectral transmittance (Transmittivity, T) can be understood as the proportion of photons transmitted from the interior of the solar cell to all photons incident on the solar cell.

[0039] In the embodiments of the present application, the external quantum efficiency can be understood as the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then transmitted to the external electrode to generate short-circuit current.

[0040] In the embodiment of the present application, the external spectral recombination efficiency (ERE) can be understood as the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination.

[0041] It is understood that for a solar cell, at the same target wavelength, the sum of the surface reflectivity, spectral transmittance, external quantum efficiency, and external spectral recombination rate is 1. Based on this, the embodiment of the present application can determine the external spectral recombination rate based on the surface reflectivity, spectral transmittance, and external quantum efficiency.

[0042] In the embodiments of the present application, the external quantum efficiency, surface reflectivity, and spectral transmittance may be test data obtained by pre-testing the solar cell. After obtaining the surface reflectivity, spectral transmittance, and external quantum efficiency, the embodiments of the present application may determine the external spectral recombination rate based on the surface reflectivity, spectral transmittance, and external quantum efficiency.

[0043] In embodiments of the present application, the present application can determine the recombination loss current of a solar cell based on the external spectral recombination rate. The recombination loss current can be understood as the magnitude of the short-circuit current lost due to electron-hole pair recombination. Furthermore, the recombination loss current can be used to quantify the recombination loss of a solar cell. Because the influence of photons that pass through the solar cell but are not utilized is excluded during the recombination loss current determination process, the accuracy of recombination loss testing is improved.

[0044] According to the test method for solar cells provided in the embodiments of the present application, test data of the solar cell is obtained, the test data including external quantum efficiency, surface reflectivity and spectral transmittance; based on the external quantum efficiency, surface reflectivity and spectral transmittance, the external spectral recombination rate of the solar cell is determined; wherein the external spectral recombination rate is the proportion of the portion of photons that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination in all the photons incident on the solar cell; since the external spectral recombination rate focuses on the portion of photons that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination, it excludes the influence of photons that are transmitted through the solar cell but not utilized, and then the recombination loss current of the solar cell is determined based on the external spectral recombination rate; the recombination loss current is used to quantitatively characterize the recombination loss of the solar cell, thereby improving the accuracy of testing the recombination loss.

[0045] In addition, the embodiment of the present application can also use the size of the composite loss current to quantitatively characterize the composite loss of the solar cell, so as to facilitate the comparison of the composite loss of solar cells of different materials and different thicknesses, and then use the size of the composite loss current to accurately measure the impact of the composite loss on the efficiency of the solar cell, providing important data basis for the optimization and improvement of solar cell materials and processes.

[0046] In practical applications, the embodiments of the present application can test solar cells to obtain test data, and respectively test and obtain the external quantum efficiency, surface reflectivity and spectral transmittance of the solar cells.

[0047] In a specific embodiment, Figure 2 As shown, in the case where the test data includes external quantum efficiency, in the above step 110, obtaining the test data of the solar cell may include:

[0048] Step 1101: testing the solar cell to obtain the external quantum efficiency of the solar cell.

[0049] It should be noted that the testing process for the external quantum efficiency of solar cells is a mature technology in this field. For example, a commonly used testing method in this field is to illuminate the solar cell with incident light of a known intensity at a target wavelength, measure the short-circuit current of the solar cell at this time, and then divide the radiant energy of the incident light by the measured short-circuit current to obtain the spectral response value (SR) of this target wavelength. By continuously changing different wavelengths and performing multiple measurements, the SR spectrum of the solar cell can be obtained. The SR spectrum is then converted to units to obtain the external quantum efficiency of the solar cell at different target wavelengths.

[0050] In addition, in an embodiment of the present application, the present application can use an integrating sphere to collect the luminous flux transmitted from the inside of the solar cell to test the spectral transmittance. For example, an embodiment of the present application can use incident light of a certain target wavelength of known intensity to illuminate the solar cell, and use a target integrating sphere to collect the luminous flux of the transmitted light transmitted from the inside of the solar cell, and divide the luminous flux of the transmitted light by the luminous flux of the incident light to obtain the spectral transmittance of this target wavelength. By continuously changing different wavelengths and performing multiple measurements, the spectral transmittance of the solar cell at different target wavelengths can be obtained.

[0051] For example, in order to accurately measure and obtain the spectral transmittance of a solar cell, in a specific embodiment, Figure 2 As shown, in the case where the test data includes external spectrum transmittance, in the above step 110, obtaining the test data of the solar cell may include:

[0052] Step 1102: After controlling the monochromator to irradiate the solar cell with incident light of a first light flux, obtaining the first light flux of the incident light, where the incident light is monochromatic light of a target wavelength;

[0053] Step 1103: Acquire a second luminous flux collected by the target integrating sphere; the target integrating sphere is disposed on a side of the solar cell away from the monochromator, and the second luminous flux is the luminous flux of the incident light after it passes through the solar cell;

[0054] Step 1104: Determine the external spectrum transmittance of the solar cell at the target wavelength based on the ratio of the second luminous flux to the first luminous flux.

[0055] The target wavelength may include multiple different wavelengths within a preset wavelength range, for example, the preset wavelength range is 300nm to 1200nm. By continuously changing different wavelengths and performing multiple measurements, the spectral transmittance of the solar cell at different target wavelengths can be obtained.

[0056] In this way, the luminous flux of the transmitted light transmitted from the interior of the solar cell is collected using an integrating sphere, and the luminous flux of the transmitted light is divided by the luminous flux of the incident light, thereby accurately testing and obtaining the spectral transmittance.

[0057] In addition, in an embodiment of the present application, the present application may also use an integrating sphere to collect the luminous flux reflected by the surface of the solar cell to test the surface reflectivity. For example, an embodiment of the present application may use incident light of a certain target wavelength of known intensity to illuminate the solar cell, and use a specified integrating sphere to collect the luminous flux of the reflected light reflected by the surface of the solar cell, and divide the luminous flux of the reflected light by the luminous flux of the incident light to obtain the surface reflectivity of the target wavelength. By continuously changing different wavelengths and performing multiple measurements, the surface reflectivity of the solar cell at different target wavelengths can be obtained.

[0058] For example, in order to accurately measure and obtain the surface reflectivity of a solar cell, when the test data includes the surface reflectivity, such as Figure 2 As shown, in the above step 110, obtaining the test data of the solar cell may include:

[0059] Step 1102: After controlling the monochromator to irradiate the solar cell with incident light of a first light flux, obtaining the first light flux of the incident light, where the incident light is monochromatic light of a target wavelength;

[0060] Step 1105: Obtain a third luminous flux collected by the designated integrating sphere; the designated integrating sphere is set on a side of the solar cell close to the monochromator, and the third luminous flux is the luminous flux of the reflected light reflected from the surface of the solar cell by the incident light;

[0061] Step 1106 : Determine the surface reflectivity of the solar cell at the target wavelength based on the ratio of the third luminous flux to the first luminous flux.

[0062] The target wavelength includes multiple different wavelengths within a preset wavelength range, for example, the preset wavelength range is 300nm to 1200nm. By continuously changing different wavelengths and performing multiple measurements, the surface reflectivity of the solar cell at different target wavelengths can be obtained.

[0063] In this way, the luminous flux of reflected light reflected from the surface of the solar cell is collected using an integrating sphere, and the luminous flux of the reflected light is divided by the luminous flux of the incident light, thereby accurately testing and obtaining the surface reflectivity.

[0064] In practical applications, sunlight is a mixed light source, including monochromatic light at multiple target wavelengths. A target monochromatic light refers to a specific wavelength that can be absorbed by a solar cell. Accordingly, the external spectral recombination rate can specifically include the external spectral recombination rate at each target wavelength.

[0065] In order to accurately determine the external spectral recombination rate of the solar cell at each target wavelength, in a specific embodiment, the test data may include the external quantum efficiency at each target wavelength, the surface reflectivity at each target wavelength, and the spectral transmittance at each target wavelength, such as Figure 3 As shown, in the solar cell testing method provided in the embodiment of the present application, in the above step 120, determining the external spectral recombination rate of the solar cell based on the external quantum efficiency, the surface reflectivity and the spectral transmittance may include:

[0066] Step 1201: Determine the external spectral recombination rate of the solar cell at each target wavelength based on the external quantum efficiency at each target wavelength, the surface reflectivity at each target wavelength, and the spectral transmittance at each target wavelength.

[0067] Among them, for each target wavelength, the sum of the surface reflectance, spectral transmittance, external quantum efficiency and external spectral recombination rate is 1. Based on this, in practical applications, the external spectral recombination rate of solar cells is calculated by the following formula:

[0068] ERE(λ)=1-EQE(λ)-T(λ)-R(λ); (1)

[0069] In the above formula (1), λ is the target wavelength, ERE(λ) is the external spectral recombination efficiency at the target wavelength, EQE(λ) is the external quantum efficiency at the target wavelength, T(λ) is the spectral transmittance at the target wavelength, and R(λ) is the surface reflectance at the target wavelength.

[0070] In practical applications, for solar cells, λ∈[λ1,λ2], λ1 is the minimum value of the target wavelength, λ2 is the maximum value of the target wavelength, λ1 to λ2 is the wavelength range of monochromatic light that can be absorbed by the solar cell, λ1 can be 300nm, and λ2 can be 1200nm.

[0071] In this way, the present embodiment obtains the surface reflectance, spectral transmittance, and external quantum efficiency measured at the target wavelength, and determines the external spectral recombination rate at the target wavelength based on the surface reflectance, spectral transmittance, and external quantum efficiency. By continuously changing different target wavelengths and performing multiple measurements, the external spectral recombination rate of the solar cell at each target wavelength can be obtained.

[0072] In another specific embodiment, in order to accurately determine the recombination loss current of a solar cell, as Figure 4 As shown, in the solar cell testing method provided in the embodiment of the present application, in the above step 130, determining the recombination loss current of the solar cell based on the external spectrum recombination rate may include:

[0073] Step 1301: Obtain the radiant flux at each target wavelength from a pre-stored radiant flux table of a reference spectrum;

[0074] Step 1302: Determine the recombination loss current of the solar cell based on the external spectrum recombination rate at each target wavelength and the radiation flux at each target wavelength.

[0075] Among them, step 1301 and step 1302 can be sub-steps of step 130.

[0076] In step 1301, the embodiment of the present application may pre-store a radiation flux table of a reference spectrum, where the radiation flux table may include radiation flux at each target wavelength, and the radiation flux at each target wavelength may be a preset constant value.

[0077] For example, for solar cells, the reference spectrum can be the AM1.5G spectrum, and the radiation flux table of the reference spectrum can be the luminous flux of each target wavelength under the AM1.5G spectrum. It can be understood that in order to quantify the attenuation degree of solar radiation, the field often uses air mass (AM) to mark the attenuation degree of solar radiation. Air mass refers to the degree of influence of the atmosphere on the reception of sunlight by the earth's surface. An air mass of AM 1.5 refers to the situation where sunlight shines on the general ground on a typical sunny day, which is closer to the actual conditions of human life. The AM 1.5G (Global, Earth) spectrum refers to the reference spectrum of the earth's surface. In order to facilitate the comparison of solar energy conversion efficiency measured at different times and places, the field generally defines the AM 1.5G spectrum as the reference spectrum for standard testing of solar energy conversion systems.

[0078] In step 1302 , a recombination loss current of a solar cell is determined based on an external spectrum recombination rate at each target wavelength and a radiation flux at each target wavelength.

[0079] It can be understood that the electron-hole pairs generated by the solar cell absorbing photon energy will be split into electrons and holes by the internal electric field of the solar cell and transmitted to the two end electrodes of the solar cell to generate short-circuit current, but some electron-hole pairs may undergo carrier recombination (i.e., electron-hole pair recombination) and be lost, and the recombination loss current can be understood as the magnitude of the short-circuit current lost by the recombination of electron-hole pairs.

[0080] For example, the recombination loss current of a solar cell is calculated using the following formula:

[0081]

[0082] In the above formula (2), J re is the recombination loss current of the solar cell, λ is the target wavelength, λ1 is the minimum value of the target wavelength, λ2 is the maximum value of the target wavelength, ERE(λ) is the external spectrum recombination rate at the target wavelength, q is the electron charge, and Φ(λ) is the radiant flux at the target wavelength.

[0083] In practical applications, for solar cells, λ1 and λ2 are the integral wavelength ranges, λ1 can be 300nm, and λ2 can be 1200nm. The value of the electron charge q is a constant 1.6×10-19C. Φ(λ) is the radiant flux at the target wavelength λ, which can be the luminous flux at wavelength λ under the AM1.5G spectrum. Its value is a constant value, and the unit is cm -2 s -1 .

[0084] In this way, based on the external spectrum recombination rate at each target wavelength and the radiation flux at each target wavelength, the magnitude of the short-circuit current lost by the solar cell due to electron-hole pair recombination can be determined. Furthermore, the magnitude of the recombination loss current can be used to accurately measure the degree of influence of the recombination loss on the efficiency of the solar cell.

[0085] In practical applications, in order to more intuitively understand the utilization of photons inside the solar cell, in a specific embodiment, Figure 5 As shown, after obtaining the test data of the solar cell in step 110, the solar cell testing method provided by the embodiment of the present application may further include:

[0086] Step 140: Determine the internal spectral recombination rate of the solar cell based on the external quantum efficiency, the surface reflectivity, and the spectral transmittance; wherein the internal spectral recombination rate is used to reflect the utilization of photons inside the solar cell.

[0087] In an embodiment of the present application, the internal spectral recombination efficiency (IRE) may include the internal spectral recombination efficiency IRE(λ) at each target wavelength λ. Specifically, the present application may determine the internal spectral recombination efficiency IRE(λ) of the solar cell at each target wavelength based on the external quantum efficiency EQE(λ) at each target wavelength, the surface reflectivity R(λ) at each target wavelength, and the spectral transmittance T(λ) at each target wavelength.

[0088] In this way, the present application can also determine the internal spectral recombination rate, eliminating the influence of photons reflected from the surface of the solar cell, and then can use the internal spectral recombination rate to specifically reflect the utilization of photons inside the solar cell.

[0089] It should be pointed out that the photons of incident light entering the interior of the solar cell can be divided into three parts. One part of the photons is transmitted out from the interior of the solar cell, one part of the photons is absorbed by the interior of the solar cell to generate electron-hole pairs, and then carrier recombination occurs and is lost, and another part of the photons is absorbed by the interior of the solar cell to generate electron-hole pairs, which are then transmitted to the external electrode to generate short-circuit current.

[0090] Based on this, in a specific example, the internal spectrum recombination rate may include the proportion of photons absorbed by the solar cell that generate electron-hole pairs and then undergo electron-hole pair recombination;

[0091] Among them, the photons absorbed by the solar cell can be divided into two parts. One part generates electron-hole pairs and then the electron-hole pairs recombine, and the other part generates electron-hole pairs and is transmitted to the external electrode to generate short-circuit current.

[0092] In this case, the internal spectral recombination rate of the solar cell is calculated by the following formula:

[0093]

[0094] In the above formula (3), λ is the target wavelength, IRE(λ) is the internal spectral recombination efficiency at the target wavelength, EQE(λ) is the external quantum efficiency at the target wavelength, T(λ) is the spectral transmittance at the target wavelength, and R(λ) is the surface reflectance at the target wavelength.

[0095] Wherein, λ∈[λ1,λ2], λ1 is the minimum value of the target wavelength, and λ2 is the maximum value of the target wavelength.

[0096] in, It can be understood as the proportion of photons absorbed by the solar cell that generate electron-hole pairs and then transmit to the external electrode to generate short-circuit current; It can be understood as the proportion of photons absorbed by solar cells that generate electron-hole pairs and then undergo electron-hole pair recombination.

[0097] In this way, the present application can use the internal spectral recombination rate to specifically reflect the proportion of photons absorbed by the solar cell that are lost due to carrier recombination inside the solar cell.

[0098] In another specific example, the internal spectrum recombination rate may also include the proportion of photons incident into the solar cell that generate electron-hole pairs and then undergo electron-hole pair recombination.

[0099] Among them, the photons incident on the inside of the solar cell can be divided into three parts. One part generates electron-hole pairs and then the electron-hole pairs recombine. One part generates electron-hole pairs and then transmits to the external electrode to generate short-circuit current. Another part of the photons is transmitted out from the inside of the solar cell.

[0100] In this case, the internal spectral recombination rate of the solar cell is calculated by the following formula:

[0101]

[0102] In the above formula (4), λ is the target wavelength, IRE(λ) is the internal spectral recombination rate at the target wavelength, IQE(λ) is the internal quantum efficiency at the target wavelength, T(λ) is the spectral transmittance at the target wavelength, and R(λ) is the surface reflectance at the target wavelength.

[0103] Wherein, λ∈[λ1,λ2], λ1 is the minimum value of the target wavelength, and λ2 is the maximum value of the target wavelength.

[0104] Among them, the internal quantum efficiency can be calculated by the external quantum efficiency and surface reflectivity, and the calculation formula is:

[0105]

[0106] In the above formula (5), IQE(λ) is the internal quantum efficiency at the target wavelength, EQE(λ) is the external quantum efficiency at the target wavelength, and R(λ) is the surface reflectivity at the target wavelength.

[0107] Substituting the above formula (5) into the above formula (4), we get formula (6):

[0108]

[0109] In the above formula (6), λ is the target wavelength, IRE(λ) is the internal spectral recombination efficiency at the target wavelength, EQE(λ) is the external quantum efficiency at the target wavelength, T(λ) is the spectral transmittance at the target wavelength, and R(λ) is the surface reflectance at the target wavelength.

[0110] In this way, the present application can use the internal spectral recombination rate to specifically reflect the proportion of photons incident into the interior of the solar cell that are lost due to carrier recombination within the solar cell.

[0111] In addition, after determining the recombination loss current of the solar cell based on the external spectrum recombination rate in step 130, as shown in FIG. Figure 6 As shown, the solar cell testing method provided in the embodiment of the present application may further include:

[0112] Step 150: adjusting the production process parameters of the solar cell based on the size of the recombination loss current of the solar cell; wherein the production process parameters include at least one of material ratio and thickness.

[0113] In the embodiments of the present application, the magnitude of the recombination loss current can be used to reflect (quantitatively characterize) the recombination loss of the solar cell, providing important data basis for optimizing and improving solar cell materials and processes.

[0114] Furthermore, in practical applications, the embodiments of the present application can produce new solar cells based on the adjusted production process parameters, and then test the composite loss current of the new solar cells. Through repeated iterations, the production process parameters can be optimized and adjusted until the composite loss current of the produced solar cells is lower than the threshold value, thereby reducing the impact of composite loss on the efficiency of solar cells and improving the efficiency of solar cells.

[0115] In practical applications, in the above step 150, adjusting the production process parameters of the solar cell based on the size of the recombination loss current of the solar cell may specifically include:

[0116] After determining the internal spectral recombination rate of the solar cell, the production process parameters of the solar cell are adjusted based on the internal spectral recombination rate of the solar cell and the recombination loss current of the solar cell.

[0117] In this way, since the internal spectrum recombination rate can specifically reflect the utilization of photons inside the solar cell, and by referring to the size of the internal spectrum recombination rate and the recombination loss current, the production process parameters can be adjusted to reduce the number of adjustments and improve the adjustment efficiency and accuracy.

[0118] In addition, based on the same concept as the solar cell testing method provided in any of the above method embodiments, an embodiment of the present application further provides a testing device.

[0119] like Figure 7 As shown, the test device 700 provided in the embodiment of the present application may include a processor 710 and a memory 720, wherein the memory 720 stores programs or instructions that can be run on the processor 710. When the program or instructions are executed by the processor 710, the steps of the test method provided in the above method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, they will not be repeated here.

[0120] The test equipment may include: a mobile phone, a tablet computer, a laptop computer, a PDA, an in-vehicle electronic device, an ultra-mobile personal computer (UMPC), a netbook or a personal digital assistant (PDA), etc., and may also include a server, a network attached storage (NAS) or a personal computer (PC), etc., and the embodiments of the present application are not specifically limited.

[0121] In addition, in practical applications, based on the same concept as the solar cell testing method provided in the above embodiment, the embodiment of the present application may also provide a solar cell testing system.

[0122] like Figure 8 As shown, the solar cell testing system provided in the embodiment of the present application may include: a light source, a monochromator, a solar cell, a designated integrating sphere, a target integrating sphere, a current acquisition module and a testing device; wherein the testing device is respectively connected to the light source, the monochromator, the designated integrating sphere, the target integrating sphere and the current acquisition module; and the current acquisition module is connected to the solar cell.

[0123] The light source may include a white light source providing continuous wavelengths.

[0124] The monochromator can generate monochromatic light of a target wavelength, which is used to irradiate the solar cell with incident light of a target wavelength of known intensity.

[0125] The designated integrating sphere is arranged on a side of the solar cell close to the monochromator, and is used to collect the luminous flux of reflected light reflected from the surface of the solar cell.

[0126] The target integrating sphere is arranged on a side of the solar cell away from the monochromator, and is used to collect the luminous flux of the transmitted light transmitted from the interior of the solar cell.

[0127] Among them, after monochromatic light of a certain target wavelength is incident on the solar cell, the current collection module is used to collect the short-circuit current generated by the solar cell.

[0128] Among them, the test equipment is used to control the operation of the light source, monochromator, designated integrating sphere, target integrating sphere and current acquisition module, and receive data from the light source, monochromator, designated integrating sphere, target integrating sphere and current acquisition module.

[0129] It should be pointed out that the testing equipment can implement each process of the testing method provided in the above method embodiment and can achieve the same technical effect. To avoid repetition, it will not be described here.

[0130] An embodiment of the present application further provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the various processes of the above-mentioned method embodiment are implemented and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0131] The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0132] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, the communication interface and the processor are coupled, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0133] An embodiment of the present application further provides a computer program product, which includes a computer program. The computer program is executed by at least one processor to implement the various processes of the above-mentioned method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0134] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0135] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus necessary general hardware platforms, of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present application.

[0136] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A method for testing a solar cell, characterized in that: include: Acquiring test data of the solar cell, wherein the test data includes external quantum efficiency, surface reflectivity, and spectral transmittance; Determining an external spectral recombination rate of the solar cell based on the external quantum efficiency, the surface reflectivity, and the spectral transmittance; wherein the external spectral recombination rate is the proportion of all photons incident on the solar cell that are absorbed by the solar cell to generate electron-hole pairs and then undergo electron-hole pair recombination; Determining a recombination loss current of a solar cell based on the external spectrum recombination rate; wherein the recombination loss current is used to quantitatively characterize the recombination loss of the solar cell; The external spectral recombination rate includes the external spectral recombination rate at each target wavelength; and determining the external spectral recombination rate of the solar cell based on the external quantum efficiency, the surface reflectivity, and the spectral transmittance includes: Determining the external spectral recombination rate of the solar cell at each target wavelength based on the external quantum efficiency at each target wavelength, the surface reflectivity at each target wavelength, and the spectral transmittance at each target wavelength; The external spectrum recombination rate of the solar cell is calculated by the following formula: ； in, is the target wavelength, is the external spectrum recombination rate at the target wavelength, is the external quantum efficiency at the target wavelength, is the spectral transmittance at the target wavelength, is the surface reflectance at the target wavelength; The recombination loss current is the magnitude of the short-circuit current lost due to the recombination of electron-hole pairs; The recombination loss current of the solar cell is calculated by the following formula: ； in, is the recombination loss current of the solar cell, is the target wavelength, is the minimum value of the target wavelength, is the maximum value of the target wavelength, is the external spectrum recombination rate at the target wavelength, is the electron charge, is the radiant flux at the target wavelength.

2. The method according to claim 1, characterized in that The external spectrum recombination rate includes the external spectrum recombination rate at each target wavelength; and determining the recombination loss current of the solar cell based on the external spectrum recombination rate includes: Obtaining the radiation flux at each target wavelength from a pre-stored radiation flux table of a reference spectrum; The recombination loss current of the solar cell is determined based on the external spectrum recombination rate at each target wavelength and the radiation flux at each target wavelength.

3. The method according to claim 1, characterized in that In the case where the test data includes external spectrum transmittance, the step of obtaining the test data of the solar cell includes: After controlling the monochromator to irradiate the solar cell with incident light of a first light flux, obtaining the first light flux of the incident light, wherein the incident light is monochromatic light of a target wavelength; Obtaining a second luminous flux collected by a target integrating sphere; the target integrating sphere is disposed on a side of the solar cell away from the monochromator, and the second luminous flux is the luminous flux of the incident light after it passes through the solar cell; Based on the ratio of the second luminous flux to the first luminous flux, an external spectrum transmittance of the solar cell at a target wavelength is determined.

4. The method according to claim 1, wherein After obtaining the test data of the solar cell, the method further includes: determining an internal spectral recombination rate of the solar cell based on the external quantum efficiency, the surface reflectivity, and the spectral transmittance; The internal spectrum recombination rate is used to reflect the utilization of photons inside the solar cell.

5. The method according to claim 4, characterized in that The internal spectral recombination rate includes the proportion of photons absorbed by the solar cell that generate electron-hole pairs and then undergo electron-hole pair recombination; the internal spectral recombination rate is calculated by the following formula: ； in, is the target wavelength, is the internal spectrum recombination rate at the target wavelength, is the external quantum efficiency at the target wavelength, is the spectral transmittance at the target wavelength, is the surface reflectivity at the target wavelength.

6. The method according to claim 4, characterized in that The internal spectral recombination rate includes the proportion of photons incident on the solar cell that generate electron-hole pairs and then undergo electron-hole pair recombination. The internal spectral recombination rate is calculated using the following formula: ； in, is the target wavelength, is the internal spectrum recombination rate at the target wavelength, is the external quantum efficiency at the target wavelength, is the spectral transmittance at the target wavelength, is the surface reflectivity at the target wavelength.

7. The method according to claim 1, characterized in that After determining the recombination loss current of the solar cell based on the external spectrum recombination rate, the method further includes: Based on the size of the recombination loss current of the solar cell, the production process parameters of the solar cell are adjusted; the production process parameters include at least one of the material ratio and thickness.

8. A testing device, characterized in that: The method comprises a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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