Light injection system and light injection method for photovoltaic cells

Abstract

The invention provides a light injection system and a light injection method for a photovoltaic cell. The light injection system comprises a supporting structure, an electromagnetic radiation source and a controller, the supporting structure is used for supporting the photovoltaic cell, and the supporting structure is movable; the electromagnetic radiation source is used for generating emergent light, and the emergent light is used for light injection of the photovoltaic cell; the controller is connected with the supporting structure and the electromagnetic radiation source, and the controller is arranged to control the moving speed of the supporting structure according to the light power of the emergent light. Through the light injection system, light injection can be carried out on the photovoltaic cell, various performances of the photovoltaic cell are improved, and damage of a lamination or heating process to the photovoltaic cell is reduced.

Description

Technical Field

[0001] This application mainly relates to the field of photovoltaic cells, and particularly to a light injection system and a light injection method for photovoltaic cells. Background Art

[0002] The performance of heterojunction cells is affected by interface defects, and the performance of heterojunction cells can be improved by light injection (light soaking) treatment. In p-type amorphous silicon, there is a Si-H-B structure. When irradiated with light with an intensity greater than 0.9 eV and a wavelength less than 1000 nm, it will transform into the metastable B-Si4, and then the film conductivity increases, and the fill factor of the cell also rises.

[0003] In addition, in the lamination process of bare cells, the photovoltaic solar cell needs to be heated. After the temperature exceeds 130 °C, the metastable B-Si4 structure or other passivation structures will be damaged. Experiments show that after the bare cell is simulated for lamination, the optical power drops by about 1%. After the photovoltaic solar cell undergoes the lamination process (the lamination process requires heating), and then through the light injection process, the damage caused by lamination will be reduced. Summary of the Invention

[0004] In order to solve the above technical problems, a light injection system and a light injection method for photovoltaic cells are provided, which can reduce the influence of interface defects on the performance of solar cells and reduce the damage caused by the lamination process.

[0005] To solve the above technical problems, this application provides a light injection system for photovoltaic cells, including: a support structure, an electromagnetic radiation source, and a controller; the support structure is used to support the photovoltaic cell, and the support structure is movable; the electromagnetic radiation source is used to generate outgoing light, and the outgoing light is used for light injection of the photovoltaic cell; the controller is connected to the support structure and the electromagnetic radiation source, and the controller is configured to control the moving speed of the support structure according to the optical power of the outgoing light.

[0006] In an embodiment of this application, the light injection system further includes a temperature detector, the temperature detector is connected to the controller, and the temperature detector is used to detect the temperature of the photovoltaic cell; the controller is further configured to control the moving speed of the support structure according to the temperature of the photovoltaic cell.

[0007] In an embodiment of this application, the light injection system further includes a lens and a cut-off filter; the lens is arranged before the cut-off filter, or the lens is arranged after the cut-off filter; the lens is used to focus the outgoing light, or to focus the outgoing light after passing through the cut-off filter; the cut-off filter is used to filter the outgoing light, or to filter the outgoing light focused by the lens.

[0008] In an embodiment of the present application, the electromagnetic radiation source further includes a first electromagnetic radiation emitter and a second electromagnetic radiation emitter; the first electromagnetic radiation emitter is used to generate near-ultraviolet light, and the emitted light includes near-ultraviolet light; the second electromagnetic radiation emitter is used to generate near-infrared light, and the emitted light includes near-infrared light.

[0009] In an embodiment of the present application, a plurality of first electromagnetic radiation emitters and a plurality of second electromagnetic radiation emitters are arranged in the following manner: a plurality of first electromagnetic radiation emitters and a plurality of second electromagnetic radiation emitters are arranged in rows at intervals in the same row; or, a plurality of first electromagnetic radiation emitters and a plurality of second electromagnetic radiation emitters are arranged in columns at intervals in the same column; or, a plurality of first electromagnetic radiation emitters form a first row, a plurality of second electromagnetic radiation emitters form a second row, and the first row and the second row are arranged in a staggered manner.

[0010] In an embodiment of the present application, the light source of the emitted light of the first electromagnetic radiation emitter is an LED light source or a laser light source; the light source of the emitted light of the second electromagnetic radiation generator is an LED light source or a laser light source.

[0011] In an embodiment of the present application, the emitted light includes sunlight, and the controller is further configured to control the moving speed of the support structure according to the optical power of the sunlight.

[0012] In an embodiment of the present application, the total optical power density of the emitted light generated by the battery radiation source is 2-10KW / M 2 .

[0013] In an embodiment of the present application, the lens is a Fresnel lens, and there is a first distance between the Fresnel lens and the photovoltaic cell.

[0014] To solve the above technical problems, the present application further provides a light injection method for a photovoltaic cell. The light injection method is applied to the light injection system as described above. The light injection method includes:

[0015] Install the photovoltaic cell on a support structure, and the support structure is movable; expose the photovoltaic cell to the emitted light generated by the electromagnetic radiation source for light injection; control the moving speed of the support structure according to the optical power of the emitted light.

[0016] The present application has the following advantages: the support structure supports the photovoltaic cell and can carry the photovoltaic cell to move, which can ensure that the photovoltaic cell can receive light evenly for light injection; the electromagnetic radiation source can provide stable emitted light; the controller can adjust the moving speed of the support structure according to the optical power to indirectly control the light injection time. Through the light injection system of the present application, light injection can be performed on the photovoltaic cell, improving the various performances of the photovoltaic cell and reducing the damage to the photovoltaic cell caused by the lamination or heating process. Description of the Drawings

[0017] The accompanying drawings are provided to offer a further understanding of the present application. They are incorporated and form a part of this application. The drawings illustrate embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the drawings:

[0018] Figure 1 is a schematic structural diagram of an optical injection system provided by an embodiment of the present application;

[0019] Figure 2 is a partial schematic structural diagram of an optical injection system provided by another embodiment of the present application;

[0020] Figure 3 is a schematic layout diagram of a first electromagnetic radiation emitter and a second electromagnetic radiation emitter provided by an embodiment of the present application;

[0021] Figure 4 is a schematic layout diagram of a first electromagnetic radiation emitter and a second electromagnetic radiation emitter provided by another embodiment of the present application;

[0022] Figure 5 is a schematic layout diagram of a first electromagnetic radiation emitter and a second electromagnetic radiation emitter provided by another embodiment of the present application;

[0023] Figure 6 is a flowchart of a method for optical injection of a photovoltaic cell provided by an embodiment of the present application.

[0024] Reference numerals

[0025] Support structure, 100;

[0026] Electromagnetic radiation source, 200;

[0027] First electromagnetic radiation source, 201;

[0028] Second electromagnetic radiation source, 202;

[0029] Controller, 300;

[0030] Lens, 400;

[0031] Cut-off filter, 500;

[0032] Violet and infrared cut-off filters, 501, 502;

[0033] Transparent substrate, 503;

[0034] Photovoltaic cell, 600;

[0035] First distance, f. Detailed implementation manners

[0036] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0037] As shown in the present application, unless the context clearly indicates an exceptional situation, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include plural. Generally speaking, the terms "including" and "comprising" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0038] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but in appropriate cases, the said technologies, methods, and devices should be regarded as part of the description. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0039] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal", and "top, bottom" are usually based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without contrary instructions, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the protection scope of the present application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0040] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be oriented "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used herein will be made accordingly.

[0041] In addition, it should be noted that the use of terms such as "first" and "second" to define components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meanings implied by each term.

[0042] Flowcharts are used in this application to illustrate the operations performed by the system according to the embodiments of this application. It should be understood that the operations before or below do not necessarily need to be executed precisely in sequence. On the contrary, they can be executed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0043] Figure 1 is a schematic structural diagram of an optical injection system provided by an embodiment of this application. As Figure 1 shown, the optical injection system includes: a support structure 100, an electromagnetic radiation source 200, and a controller 300; the support structure 100 is used to support the photovoltaic cell 600, and the support structure 100 is movable; the electromagnetic radiation source 200 is used to generate outgoing light, and the outgoing light is used for optical injection of the photovoltaic cell 600; the controller 300 is connected to the support structure 100 and the electromagnetic radiation source 200, and the controller 300 is configured to control the moving speed of the support structure 100 according to the optical power of the outgoing light.

[0044] The photovoltaic cell 600 of the present application may be a cell or a photovoltaic module with a frame. The types of the photovoltaic cell 600 may include heterojunction photovoltaic cells, tunnel oxide passivated contact cells, back contact photovoltaic cells, perovskite photovoltaic cells, etc. The support structure 100 can support one or more photovoltaic cells 600 and drive the movement of the photovoltaic cells 600, so that different photovoltaic cells 600 or different regions on one photovoltaic cell 600 receive light injection.

[0045] In some embodiments, universal wheels may be provided on the support structure 100, and the rotation of the universal wheels is controlled by a motor to drive the movement of the support structure 100. The controller 300 can control the rotation speed of the motor according to the optical power of the emitted light, thereby controlling the rotation of the universal wheels and further controlling the moving speed of the support structure. In some embodiments, the support structure 100 may be a transmission device, and the transmission device includes a conveyor belt. The photovoltaic cell 600 is placed on the conveyor belt, and the movement of the photovoltaic cell 600 is driven by the conveyor belt. The controller 300 can control the moving speed of the conveyor belt according to the optical power of the emitted light. The electromagnetic radiation source 200 may be arranged in parallel with the photovoltaic cell 600, so that the emitted light produced by the electromagnetic radiation source 200 is perpendicularly irradiated on the surface of the photovoltaic cell 600.

[0046] In some embodiments, the controller 300 may be an electronic device such as a microcontroller (MCU), a programmable logic controller (PLC), and a field programmable gate array (FPGA). By controlling the moving speed of the support structure 100, the controller 300 can also indirectly control the light injection time of the photovoltaic cell 600. For example, in the case where the optical power of the emitted light is strong, the moving speed can be increased, and accordingly the light injection time will be reduced.

[0047] In some embodiments, the electromagnetic radiation source 200 may be fixedly arranged, and only the photovoltaic cell 600 or a partial area of the photovoltaic cell 600 that needs to be subjected to light injection is adjusted through the support structure 100. In other embodiments, the electromagnetic radiation source 200 may also be movably arranged, and the photovoltaic cell or a partial area of the photovoltaic cell that needs to be subjected to light injection is adjusted by the movement of the electromagnetic radiation source 200, or the movement of the electromagnetic radiation source 200 and the support structure 100. The movement of the electromagnetic radiation source 200 and the movement of the support structure 100 can both be controlled by the controller 300. In some embodiments, the size of the radiation area of the emitted light can be set according to the actual situation. The size of the radiation area of the emitted light can be smaller or larger than the size of the photovoltaic cell 600. The emitted light can perform light injection on one photovoltaic cell 600, or can perform light injection on a partial area of one photovoltaic cell 600; it can perform light injection on multiple photovoltaic cells 600, or can perform light injection on partial areas of multiple photovoltaic cells 600.

[0048] In some embodiments, the optical injection system further includes a temperature detector, which is connected to the controller 300 and is used to detect the temperature of the photovoltaic cell 600. The controller 300 is further configured to control the moving speed of the support structure 100 according to the temperature of the photovoltaic cell 600. The temperature of the photovoltaic cell 600 will rise under the optical injection condition, and when the temperature of the photovoltaic cell 600 exceeds a threshold, it will cause damage to the photovoltaic cell 600. Therefore, in these embodiments, the temperature detector detects the temperature of the photovoltaic cell 600 in real time to prevent the photovoltaic cell 600 from being damaged due to excessive temperature. In some embodiments, the temperature detector is an infrared temperature detector, and the temperature is measured by detecting the infrared radiation emitted by the photovoltaic cell 600. The temperature detector is communicatively connected to the controller 300, and the controller 300 can obtain the temperature data detected by the temperature detector. In some embodiments, multiple temperature detectors can be provided to detect the temperatures of multiple regions of the photovoltaic cell 600, and the average value is used as the temperature of the photovoltaic cell 600 to improve the accuracy of temperature detection.

[0049] In some embodiments, the controller 300 controls the moving speed of the support structure 100 according to the temperature of the photovoltaic cell 600 as follows: when the temperature of the photovoltaic cell 600 exceeds the first threshold, the moving speed of the support structure 100 is increased to quickly move the photovoltaic cell 600 out of the illumination area of the electromagnetic radiation source 200 to cool the photovoltaic cell 600. When the temperature of the photovoltaic cell 600 is too high, the photovoltaic cell will be moved out of the radiation range of the outgoing light. At this time, the photovoltaic cell 600 may not have completed the optical injection. To complete the optical injection of the photovoltaic cell 600 with too high temperature, the controller 300 can re-perform the optical injection on the photovoltaic cell 600 after the temperature of the photovoltaic cell 600 has decreased due to cooling. The first threshold can be set according to different photovoltaic cells 600. For example, when the photovoltaic cell 600 is a heterojunction photovoltaic cell, when the temperature of the photovoltaic cell 600 exceeds 100 °C or is close to 100 °C, the support structure 100 is controlled to move quickly so that the photovoltaic cell 600 quickly exits the radiation area of the outgoing light. After the overheated photovoltaic cell 600 exits the radiation area of the outgoing light, the electromagnetic radiation source 200 can perform optical injection on the next photovoltaic cell 600 or the next area of the photovoltaic cell 600. The limit temperature of the heterojunction photovoltaic cell is 150 °C. In some embodiments, the first threshold can be set to 150 °C. When the temperature of the photovoltaic cell 600 is close to 150 °C, the controller 300 can control the support structure 100 to move quickly so that the photovoltaic cell 600 quickly exits the radiation area of the outgoing light to prevent the photovoltaic cell 600 from being damaged due to excessive temperature and performance degradation.

[0050] In some embodiments, when the temperature of the photovoltaic cell 600 exceeds the first threshold, the electromagnetic radiation source can also be turned off and the moving speed of the support structure 100 can be increased to quickly move the photovoltaic cell 600 out of the radiation range of the emitted light. After the overheated photovoltaic cell 600 exits the radiation area of the emitted light, the electromagnetic radiation source is turned on again to perform optical injection on the next photovoltaic cell 600 or the next area of the photovoltaic cell 600.

[0051] Figure 2 is a partial structural schematic diagram of another optical injection system provided by the present application. As Figure 2 shown, in some embodiments, the electromagnetic radiation source 200 further includes a first electromagnetic radiation emitter 201 and a second electromagnetic radiation emitter 202. Among them, the first electromagnetic radiation emitter 201 is used to generate near-ultraviolet light, that is, the emitted light includes near-ultraviolet light. The wavelength range of the near-ultraviolet light generated by the first electromagnetic radiation generator 201 is 300 - 550 nm. Preferably, the wavelength range of the near-ultraviolet light is between 400 - 450 nm. The second electromagnetic radiation emitter 202 is used to generate near-infrared light, that is, the emitted light includes near-infrared light. The wavelength range of the near-infrared light generated by the second electromagnetic radiation generator 202 is 800 - 1200 nm. Preferably, the wavelength range of the near-infrared light is 900 - 1100 nm. The effect of setting multiple electromagnetic radiation sources 200 is that the emitted light can cover a wider spectral range, so as to be able to more comprehensively excite the carriers in the photovoltaic cell 600 and improve the effect of optical injection. The two electromagnetic radiation emitters can be independently controlled to adjust their respective light intensities and wavelengths according to specific application requirements, providing a more flexible optical injection scheme to adapt to different types of photovoltaic cells 600 and working conditions. In some embodiments, the light source of the emitted light of the first electromagnetic radiation emitter 201 is an LED light source or a laser light source; the light source of the emitted light of the second electromagnetic radiation generator 202 is an LED light source or a laser light source.

[0052] In some embodiments, the total optical power density of the emitted light generated by the battery radiation source is greater than 10 KW / M 2 . For example, if the optical power density of the emitted light generated by the first electromagnetic radiation emitter 201 is greater than 5 KW / M 2 , and the optical power density of the emitted light generated by the second electromagnetic radiation emitter 202 is greater than 5 KW / M 2 , then the total optical power density is greater than 10 KW / M 2 . For example, if the optical power density of the emitted light generated by the first electromagnetic radiation emitter 201 is greater than 10 KW / M 2 , and the optical power density of the emitted light generated by the second electromagnetic radiation emitter 202 is greater than 10 KW / M 2 , then the total optical power density is greater than 20 KW / M 2。At this total optical power density, optical injection can enhance the excitation of carriers, improve the efficiency of optical injection, and also improve the passivation effect, increasing the open-circuit voltage and fill factor of the battery. In some embodiments, the total optical power density of the emitted light generated by the battery radiation source ranges from 2 - 10 KW / M 2 between, for example, the total optical power density is 2 KW / M 2 , 3 KW / M 2 , 4 KW / M 2 , 5 KW / M 2 , 6 KW / M 2 , 7 KW / M 2 , 8 KW / M 2 , 9 KW / M 2 and 10 KW / M 2 .

[0053] In some embodiments, the first electromagnetic radiation emitter 201 is provided with a cooling device, and the second electromagnetic radiation emitter 202 is also provided with a cooling device. The cooling device is used to cool the first electromagnetic radiation emitter 201 and the second electromagnetic radiation emitter 202, preventing the first electromagnetic radiation generator 201 and the second electromagnetic radiation generator 202 from burning out due to excessive temperature. The cooling method of the cooling device can be air cooling, using air as the medium; or water cooling, using water as the medium.

[0054] As Figures 3 - 5 shown, in some embodiments, a plurality of first electromagnetic radiation emitters 201 and a plurality of second electromagnetic radiation emitters 202 have various arrangement patterns. As Figure 3 shown, a plurality of first electromagnetic radiation emitters 201 and a plurality of second electromagnetic radiation emitters 202 are arranged at intervals in the same row to form several rows. As Figure 4 shown, a plurality of first electromagnetic radiation emitters 201 and a plurality of second electromagnetic radiation emitters 202 are arranged at intervals in the same column to form several columns. As Figure 5 shown, a plurality of first electromagnetic radiation emitters 201 form the first row, and a plurality of second electromagnetic radiation emitters 202 form the second row, with the first row and the second row arranged in a staggered manner. By setting the arrangement pattern of the first electromagnetic radiation emitter 201 and the second electromagnetic radiation emitter 202, the radiation uniformity of the emitted light and the efficiency of optical injection can be improved.

[0055] In some embodiments, the optical injection system can be used in an indoor environment. When used indoors, the optical injection is not affected by sunlight radiation. The optical power of the emitted light generated by the first electromagnetic radiation emitter 201 and the second electromagnetic emitter 202 is relatively stable. When performing optical injection on the same type of photovoltaic cell 600, a stable optical power can be maintained, so the moving speed of the support structure 100 can be relatively stably controlled within a threshold range. In some embodiments, the moving speed range of the support structure 100 is between 0 - 50 m / min. For example, the moving speeds of the support structure 100 are 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 m / min. When performing optical injection on different types of photovoltaic cells 600, the required optical power may be different, and the moving speed of the support structure 100 needs to be controlled according to the optical power of the first electromagnetic radiation emitter 201 and the second electromagnetic radiation emitter 202. For example, when the total optical power of the first electromagnetic radiation emitter 201 and the second electromagnetic radiation emitter 202 is 10 KW / M 2 , the speed of the support structure 100 is 40 m / min; when the total optical power of the first electromagnetic radiation emitter 201 and the second battery radiation emitter 202 is 8 KW / M 2 , the speed of the support structure 100 is 30 m / min. When performing optical injection in an indoor environment, the temperature of the photovoltaic cell 600 can be detected in real time by a temperature detector, and the moving speed of the support structure 100 can be controlled according to the temperature of the photovoltaic cell 600. The specific control method can refer to the content described above. In some embodiments, when using the optical injection system in an indoor environment, a cut-off filter 500 can be combined to filter visible light, so that the photovoltaic cell 600 only receives the emitted light generated by the first electromagnetic radiation emitter and the second electromagnetic radiation emitter.

[0056] In some embodiments, as Figure 2 shown, the optical injection system further includes a lens 400 and a cut-off filter 500. For the directional terms "before", "after", and "front end" in the following content, the emission direction of the emitted light ( Figure 2 the arrow in) is the forward direction. The lens 400 is disposed before the cut-off filter 500, or the lens 400 is disposed after the cut-off filter 500. The lens 400 is used to focus the emitted light, or to focus the emitted light after passing through the cut-off filter 500. The cut-off filter 500 is used to filter the emitted light, or to filter the emitted light focused by the lens 400. As Figure 2As shown, the purpose of setting the lens 400 is to increase the light intensity per unit area of the photovoltaic cell 600 and improve the efficiency of light injection. The lens 400 has a focal length parameter, and the focal length determines the position where the light converges. Therefore, the set distance between the lens 400 and the photovoltaic cell 600 is equal to the focal length of the lens 400. For example, when the photovoltaic cell 600 is arranged in parallel with the electromagnetic radiation source 200, the height between the photovoltaic cell 600 and the electromagnetic radiation source 200 is equal to the focal length of the lens 400.

[0057] In some embodiments, the lens 400 can be a converging Fresnel lens, and the Fresnel lens has a good light-concentrating effect. The Fresnel lens consists of a series of concentric annular refractive surfaces, and these annular refractive surfaces gradually become larger from the center outwards. Each annular refractive surface is equivalent to a small refractive prism, and light refracts on these refractive surfaces, ultimately achieving the focusing or divergence of light. Compared with traditional lenses, the Fresnel lens removes most of the material in the middle of the lens and only retains the refractive surface part, so its thickness is greatly reduced and its weight is also lighter. The design of the Fresnel lens is based on the principle of light refraction: when light enters from one medium into another medium, refraction occurs. The Fresnel lens utilizes this principle and, by precisely designing the angles and curvatures of each annular refractive surface, enables light to refract in a predetermined direction when passing through the lens. For a converging Fresnel lens, after light enters the lens parallel to the principal optical axis, it refracts through each refractive surface and ultimately converges at a focal point. The principal optical axis is the benchmark for the convergence or divergence of light, and all light rays are focused or collimated around this axis. The Fresnel lens also has a focal length parameter, which determines the degree of light convergence or divergence. The size of the focal length depends on the radius of curvature of the lens, the angle of the refractive surface, and the refractive index of the material, etc. As Figure 2 shown, in some embodiments, a first distance f is set between the Fresnel lens and the photovoltaic cell 600, and the first distance f is the same as the focal length parameter of the Fresnel lens, so that the Fresnel lens converges the incident light.

[0058] In the light injection process, different types of photovoltaic cells 600 respond differently to light waves. Using light waves with an appropriate wavelength for light injection can improve the efficiency and effect of light injection. For example, perovskite photovoltaic cells respond well to visible light and some near-ultraviolet light. In some embodiments of the present application, by using a cut-off filter 500, appropriate light can be selected for light injection to improve the effect of light injection. Additionally, when using sunlight for light injection, filtering out light with a specific wavelength using a cut-off filter can reduce the heat radiated by sunlight to the photovoltaic cell 600, thereby avoiding the problem of damage to the photovoltaic cell 600 caused by overheating during light injection.

[0059] The cut-off filter 500 is an optical filter that allows light within a specific wavelength range to pass through while blocking light of other wavelengths. Among them, the ultraviolet and infrared cut-off filter is a filter with cut-off characteristics in the ultraviolet and infrared bands. The position of the cut-off filter 500 can be before the lens 400 or after the lens 400. The cut-off filter 500 can directly filter the outgoing light of the electromagnetic radiation source 200, or filter the outgoing light after being focused by the lens 400. In some embodiments, when the optical injection system performs optical injection outdoors or in an open-air environment, a ultraviolet and infrared cut-off filter can be used as the cut-off filter 500 to select sunlight of appropriate wavelengths for optical injection.

[0060] In some embodiments, photovoltaic cells such as heterojunction photovoltaic cells (780nm - 1100nm) and TOPCon photovoltaic cells (780nm - 1100nm) have better optical effects on long-wave light. The short-wave sunlight can be filtered by the cut-off filter 500, and the long-wave sunlight can be used for optical injection into the heterojunction photovoltaic cells and TOPCon photovoltaic cells to improve the efficiency of optical injection. For example, the cut-off filter 500 is a visible light cut-off filter, which can block visible light and allow infrared light to pass through.

[0061] As Figure 2 shown, in some embodiments, the ultraviolet and infrared cut-off filter includes a transparent substrate 503. A plurality of layers of ultraviolet and infrared cut-off films 501, 502 are deposited on the front side of the transparent substrate, and a plurality of layers of ultraviolet and infrared cut-off films 501, 502 are also deposited on the rear side of the transparent substrate 503. The number of layers of the ultraviolet and infrared cut-off films 501, 502 on the rear side of the transparent substrate 503 is equal to the number of layers of the ultraviolet and infrared cut-off films 501, 502 on the front side of the transparent substrate 503. The ultraviolet and infrared cut-off films 501, 502 are infrared cut-off films provided with absorption pigments capable of strongly absorbing ultraviolet light. Regarding the structure, materials, and working principles of the infrared cut-off films, reference can be made to patent documents (CN106707379B and CN107615115B). The absorption pigments capable of strongly absorbing ultraviolet light and the setting methods of the absorption pigments can be referred to patent document (CN105074513A). The materials capable of strongly absorbing ultraviolet light can also be rare earth element-doped compounds, such as cerium oxide (CeO2).

[0062] The infrared and ultraviolet cut-off filter has certain index parameters. The infrared and ultraviolet cut-off filter can filter both infrared light and ultraviolet light, and has the wavelength positions where infrared light is effectively cut off and the wavelength positions where ultraviolet light is effectively cut off. For example, the infrared cut-off wavelength of a certain filter is 750 nm, and the ultraviolet cut-off wavelength is 400 nm, which means that infrared light with a wavelength greater than 750 nm and ultraviolet light with a wavelength less than 400 nm will be largely cut off. The transmittance refers to the proportion of light passing through the filter within the wavelength range allowed to pass by the filter. Generally, a higher transmittance is required in the visible light band (usually 400 - 700 nm), for example, the transmittance reaches more than 80%, to ensure the effective utilization of the target light. The cut-off depth indicates the degree of suppression of the filter for the light in the cut-off band. The greater the cut-off depth, the better the cut-off effect on infrared light and ultraviolet light. It is usually expressed in decibels (dB). For example, the cut-off depth of 30 dB means that the intensity of the light in the cut-off band is suppressed to 1 / 1000 of the original.

[0063] When performing optical injection, some photovoltaic cells 600 have a better response to visible light. For example, perovskite photovoltaic cells have a better response to blue light of 405 nm or visible light of 600 nm to 850 nm. When using sunlight for optical injection in an outdoor environment, an infrared and ultraviolet cut-off filter can be used to filter light waves with a wavelength lower than 405 nm and light waves with a wavelength higher than 850 nm. At this time, the ultraviolet cut-off wavelength of the infrared and ultraviolet cut-off filter is 405 nm, the infrared cut-off wavelength of the infrared and ultraviolet cut-off filter is 850 nm, the transmittance of the infrared and ultraviolet cut-off filter can be designed to be 95%, and the cut-off depth is 30 dB. Using the sunlight filtered by the infrared and ultraviolet cut-off filter for optical injection can improve the excitation and separation efficiency of carriers. In this application, different types of photovoltaic cells have a better response to visible light of different wavelengths, and infrared and ultraviolet cut-off filters adapted to different types of photovoltaic cells can be designed according to different types of photovoltaic cells. There are many optional schemes for the infrared and ultraviolet cut-off filter, and the optional schemes of the infrared and ultraviolet cut-off filter will not be listed one by one here, nor will the materials of the infrared and ultraviolet cut-off filter be restricted.

[0064] In some embodiments, the emitted light includes sunlight, and the controller 300 is further configured to control the moving speed of the support structure 100 according to the optical power of the sunlight. When the emitted light includes sunlight, the electromagnetic radiation source 200 is the sun, and the process of light injection is carried out in an outdoor environment or an open-air environment, and the photovoltaic cell 600 is exposed to the sunlight environment. Since the incident angle of sunlight changes at different times, an autofocus or tracking system can be adopted to adjust the position and angle of the lens 400 in real time to compensate for the change of the incident angle of sunlight and ensure that the light is always accurately focused. The solutions of the autofocus and tracking system can refer to the published patent (CN115843765B), which will not be elaborated here. Sunlight includes visible light, ultraviolet light, and infrared light. The sunlight with the required wavelength can be screened by the cut-off filter 500, and the structure of the cut-off filter 500 is set as described above. Light injection is to excite the carriers in the photovoltaic cell 600 through light illumination, improve the passivation effect of the photovoltaic cell 600, and thus improve the photoelectric conversion efficiency of the photovoltaic cell 600. In this process, it is not necessary for the photovoltaic cell 600 to generate electricity simultaneously. The emitted light including sunlight can reduce the energy consumption brought by light injection and reduce the production cost. Sunlight is a renewable clean energy. Using sunlight for light injection can achieve energy conservation and emission reduction, reduce the negative impact on the atmospheric environment, and contribute to protecting the health of the earth's ecosystem. The wavelength range of sunlight is large, and the applicable range is wide, which can be applied to the light injection of different types of photovoltaic cells 600.

[0065] In an open-air environment, if the weather conditions are good, such as sunny days, the intensity of sunlight is relatively strong. If the weather conditions are poor, such as cloudy or overcast days, the intensity of sunlight is relatively weak. In some embodiments, to adapt to the changes in various weather conditions, the controller 300 is further configured to control the moving speed of the support structure 100 according to the optical power of the sunlight. For example, on cloudy days, the optical power of sunlight is poor, and the moving speed of the support structure 100 can be reduced to increase the time of light injection. In some embodiments, if the optical power of sunlight is not sufficient to meet the conditions of light injection, the first electromagnetic radiation source 201 and the second electromagnetic radiation source 202 can be started to compensate for the optical power. On sunny days, the optical power of sunlight is strong, and the moving speed of the support structure 100 can be increased to reduce the time of light injection and improve the efficiency of light injection. In some embodiments, if the optical power of sunlight is strong, the first electromagnetic radiation source 201 and the second electromagnetic radiation source 202 are turned off. During the process of light injection, to prevent the temperature of the photovoltaic cell 600 from being too high, the moving speed of the support structure 100 can also be controlled according to the temperature of the photovoltaic cell 600. The method of controlling the moving speed of the support structure 100 according to the temperature is as described above.

[0066] As Figure 6As shown, the present application also provides a light injection method for a photovoltaic cell 600. The light injection method is applied to the light injection system as described above, and the light injection method includes:

[0067] S610. Mount the photovoltaic cell 600 on the support structure 100, and the support structure 100 is movable;

[0068] S620. Expose the photovoltaic cell 600 to the emitted light generated by the electromagnetic radiation source 200 for light injection;

[0069] S630. Control the moving speed of the support structure 100 according to the optical power of the emitted light.

[0070] The light injection method of the present application is implemented using the light injection system described above. Therefore, the description content about the light injection system above can be used to explain the light injection method of the present application, and will not be elaborated here. Among them, the execution subject of step S630 can be the controller in the light injection system described above.

[0071] In some embodiments, the light injection method of the present application further includes: controlling the moving speed of the support structure according to the temperature of the photovoltaic cell.

[0072] Through the light injection method of the present application, light injection can be performed on the photovoltaic cell, improving the performance of the photovoltaic cell and reducing the damage to the photovoltaic cell caused by the lamination or heating process.

[0073] The present application uses specific terms to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined.

[0074] Similarly, it should be noted that, in order to simplify the expression of the disclosure of the present application and thus help the understanding of one or more inventive embodiments, in the description of the embodiments of the present application above, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the subject of the present application are more than the mentioned features. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0075] In some embodiments, numbers are used to describe components and the quantity of attributes. It should be understood that such numbers used in the description of embodiments are, in some examples, modified by the modifiers "about", "approximate" or "substantially". Unless otherwise stated, "about", "approximate" or "substantially" indicate that the said numbers are allowed to have a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are all approximate values, and these approximate values can be changed according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used in some embodiments of this application to confirm the breadth of their scope are approximate values, in specific embodiments, the setting of such numerical values is as precise as possible within the feasible range.

Claims

1. A light injection system for a photovoltaic cell, characterized in that, Comprising: A support structure for supporting the photovoltaic cell, and the support structure is movable; An electromagnetic radiation source for generating outgoing light, and the outgoing light is used for light injection of the photovoltaic cell; A controller connected to the support structure and the electromagnetic radiation source, and the controller is configured to control the moving speed of the support structure according to the optical power of the outgoing light.

2. The optical injection system according to claim 1, wherein The light injection system further includes a temperature detector connected to the controller, and the temperature detector is used to detect the temperature of the photovoltaic cell; The controller is further configured to control the moving speed of the support structure according to the temperature of the photovoltaic cell.

3. The optical injection system according to claim 1 or 2, characterized in that, The light injection system further includes a lens and a cut-off filter; The lens is disposed before the cut-off filter, or the lens is disposed after the cut-off filter; The lens is used to focus the outgoing light, or to focus the outgoing light after passing through the cut-off filter; The cut-off filter is used to filter the outgoing light, or to filter the outgoing light focused by the lens.

4. The optical injection system according to claim 3, wherein The electromagnetic radiation source further includes a first electromagnetic radiation emitter and a second electromagnetic radiation emitter; The first electromagnetic radiation emitter is used to generate near-ultraviolet light, and the outgoing light includes the near-ultraviolet light; The second electromagnetic radiation emitter is used to generate near-infrared light, and the outgoing light includes the near-infrared light.

5. The optical injection system according to claim 4, wherein A plurality of the first electromagnetic radiation emitters and a plurality of the second electromagnetic radiation emitters are arranged in the following manner: A plurality of the first electromagnetic radiation emitters and a plurality of the second electromagnetic radiation emitters are arranged in rows at intervals in the same row; or, A plurality of the first electromagnetic radiation emitters and a plurality of the second electromagnetic radiation emitters are arranged in columns at intervals in the same column; or, A plurality of the first electromagnetic radiation emitters form a first row, and a plurality of the second electromagnetic radiation emitters form a second row, and the first row and the second row are arranged in a staggered manner.

6. The optical injection system according to claim 4, characterized in that The light source of the outgoing light of the first electromagnetic radiation emitter is an LED light source or a laser light source; The light source of the outgoing light of the second electromagnetic radiation generator is an LED light source or a laser light source.

7. The optical injection system according to claim 4, wherein, The outgoing light includes sunlight, The controller is further configured to control the moving speed of the support structure according to the optical power of the sunlight.

8. The optical injection system according to claim 1, wherein The total optical power density of the emitted light generated by the electromagnetic radiation source is 2 - 10 KW / M 2 .

9. The optical injection system according to claim 3, characterized in that The lens is a Fresnel lens, and there is a first distance between the Fresnel lens and the photovoltaic cell.

10. A light injection method for a photovoltaic cell, characterized in that, The light injection method is applied to the light injection system according to any one of claims 1-9, and the light injection method includes: Mounting the photovoltaic cell on the support structure, and the support structure is movable; Exposing the photovoltaic cell to the outgoing light generated by the electromagnetic radiation source for light injection; Controlling the moving speed of the support structure according to the optical power of the outgoing light.

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