Photovoltaic modules and their manufacturing methods

Abstract

This application provides a photovoltaic module and its manufacturing method, comprising the following steps: providing at least one solar cell; pre-treating the solar cell to obtain a pre-treated layer, the pre-treatment including energizing and irradiating the solar cell with ultraviolet light; providing a first encapsulation structure and a second encapsulation structure, the first encapsulation structure including a first cover plate and a first encapsulation layer, the second encapsulation structure including a second cover plate and a second encapsulation layer; and stacking and laminating the first cover plate, the first encapsulation layer, the pre-treated layer, the second encapsulation layer, and the second cover plate to obtain a photovoltaic module. This application pre-treats the solar cells before assembling them into a photovoltaic module, specifically by energizing and irradiating the solar cells with ultraviolet light, to reduce non-radiative recombination in the solar cells, thereby improving the passivation effect of the solar cells and thus increasing the output power of the photovoltaic module composed of these solar cells.

Description

Technical Field

[0001] This application relates to the field of photovoltaic production technology, and in particular to a photovoltaic module and its preparation method. Background Technology

[0002] Photovoltaic modules (also called solar panels) are the core and most important part of a solar power generation system. Their function is to convert solar energy into electrical energy, which can then be stored in batteries or used to power loads.

[0003] Solar cells are the basic unit for photoelectric conversion in photovoltaic (PV) modules, and their quality largely determines the output power and overall quality of the PV module. However, the output power of a PV module composed of pre-fabricated solar cells is generally stable. If a particular solar cell is found to be of poor quality, the output power of the resulting PV module will be lower, affecting the overall performance and market competitiveness of the PV module. Typically, researchers have no choice but to discard the substandard solar cells, resulting in significant waste. Summary of the Invention

[0004] This application provides a photovoltaic module and its preparation method. By energizing and irradiating the prepared solar cells with ultraviolet light, the output power of the photovoltaic module composed of the solar cells can be improved.

[0005] In a first aspect, embodiments of this application provide a method for providing at least one battery cell, pre-treating the battery cell to obtain a pre-treated layer, wherein the pre-treating includes energizing the battery cell and irradiating it with ultraviolet light;

[0006] A first packaging structure and a second packaging structure are provided, wherein the first packaging structure includes a first cover plate and a first packaging layer, and the second packaging structure includes a second cover plate and a second packaging layer;

[0007] The first cover plate, the first encapsulation layer, the pre-treated sheet, the second encapsulation layer, and the second cover plate are stacked and laminated to obtain a photovoltaic module.

[0008] Secondly, embodiments of this application provide a photovoltaic module, which is prepared by the photovoltaic module preparation method described in the first aspect.

[0009] The technical solution provided in this application can achieve the following beneficial effects:

[0010] This application pre-treats the solar cells before assembling them into a photovoltaic module. The pre-treatment specifically includes energizing and irradiating the cells with ultraviolet light. During energizing, a large number of non-equilibrium carriers are injected into the cells. These carriers recombine in the PN junction region, generating heat and a large number of photons. The heat raises the temperature of the PN junction region, activating the hydrogen (H) activity within the cells. Irradiating the cells with ultraviolet light breaks some of the Si-H bonds, altering the valence state of some H atoms and removing excess Si-H bonds. This reduces non-radiative recombination, improving the passivation effect and thus increasing the output power of the photovoltaic module composed of these cells. It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0011] Figure 1 This is a flowchart illustrating the fabrication process of a photovoltaic module provided in an embodiment of this application.

[0012] Figure 2 This is a schematic diagram of the structure for energizing and irradiating a battery string with ultraviolet light, provided in an embodiment of this application.

[0013] Figure 3 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application.

[0014] Figure label:

[0015] 100 - Photovoltaic modules;

[0016] 1-Pre-treatment of the film;

[0017] 11-Battery string;

[0018] 111-cell battery;

[0019] 2-First packaging structure;

[0020] 21-First cover plate;

[0021] 22 - First encapsulation layer;

[0022] 3-Second packaging structure;

[0023] 31 - Second cover plate;

[0024] 32 - Second encapsulation layer;

[0025] 10-Positive electrode;

[0026] 20 - Negative electrode;

[0027] 30-Ultraviolet irradiation device.

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0030] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" used in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should also be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0032] In related technologies, solar cells are typically optimized during the fabrication process to obtain high-quality cells, which are then assembled into photovoltaic modules. Once finished solar cells are produced, it becomes difficult to further optimize their performance, forcing researchers to discard lower-quality cells, resulting in significant waste. Furthermore, Si-H bonds are primarily found in the passivation layer and surface treatment layer of the solar cell. During the thermal processing of the cell, new unpassivated Si-H bonds are easily generated, increasing the number of dangling bonds on the cell surface. This increases surface recombination of charge carriers and reduces the passivation performance of the solar cell.

[0033] Therefore, this application provides a method for manufacturing a photovoltaic module 100. Figure 1 A flowchart illustrating the fabrication process of the photovoltaic module 100 of this application is shown, as follows: Figure 1 As shown, it includes the following steps:

[0034] At least one solar cell 111 is provided, and the solar cell 111 is pretreated to obtain a pretreated layer 1. The pretreatment includes energizing the solar cell 111 and irradiating it with ultraviolet light.

[0035] A first packaging structure 2 and a second packaging structure 3 are provided. The first packaging structure 2 includes a first cover plate 21 and a first packaging layer 22. The second packaging structure 3 includes a second cover plate 31 and a second packaging layer 32.

[0036] The first cover plate 21, the first encapsulation layer 22, the pre-treated sheet layer 1, the second encapsulation layer 32, and the second cover plate 31 are stacked and laminated to obtain the photovoltaic module 100.

[0037] In the above technical solution, this application pre-treats the solar cells 111 before assembling them into a photovoltaic module 100. The pre-treatment specifically includes energizing and irradiating the solar cells 111 with ultraviolet light. During the energizing process, a large number of non-equilibrium carriers are injected into the solar cells 111. These non-equilibrium carriers recombine in the PN junction region of the solar cells 111, generating heat and a large number of photons. The generated heat raises the temperature of the PN junction region of the solar cells 111, activating the hydrogen (H) activity within the solar cells 111. Irradiating the solar cells 111 with ultraviolet light destroys some of the Si-H bonds in the solar cells 111, changing the valence state of some H atoms and removing excess Si-H bonds. This reduces non-radiative recombination in the solar cells 111, thereby improving the passivation effect of the solar cells 111 and ultimately increasing the output power of the photovoltaic module 100 composed of these solar cells 111.

[0038] In this application, nonradiative recombination refers to the direct recombination of electrons and holes without the emission of photons, which results in energy loss in the form of heat, thereby reducing the photoelectric conversion efficiency of the battery.

[0039] Compared to related technologies that optimize from the perspective of battery structure, this application innovatively applies electricity and ultraviolet light to the battery cells 111 before assembling them into a photovoltaic module 100. This simple process can improve the passivation performance of the already prepared battery cells 111, increase the open-circuit voltage and fill factor of the battery cells 111, reduce waste of the battery cells 111, and lower the manufacturing cost, thereby improving the output performance and market competitiveness of the photovoltaic module 100.

[0040] The preparation method of this application is described in detail below.

[0041] S100, at least one battery cell 111 is provided, and the battery cell 111 is pre-treated to obtain a pre-treated layer 1. The pre-treatment includes energizing the battery cell 111 and irradiating it with ultraviolet light.

[0042] In some embodiments, the number of battery cells 111 in this application is at least one, specifically one, two, three, four, or five. When there is only one battery cell 111, both ends of the battery cell 111 are directly energized, and the surface of the battery cell 111 is irradiated with ultraviolet light. It is understood that energizing a single battery cell 111 can be done using a probe. When there are two or more battery cells 111, at least two battery cells 111 are welded together before pretreatment to obtain one or more battery strings 11, and then both ends of the battery strings 11 are energized, and the battery cells 111 in each battery string 11 are irradiated with ultraviolet light. This application does not limit the size of the battery cells 111; they can be of any size.

[0043] In some embodiments, this application does not limit the method and process of welding at least two battery cells 111. For example, when welding multiple battery cells 111, a stacking welding technique can be used to connect them, so that the multiple battery cells 111 are connected in series to form a battery string 11. The multiple battery strings 11 are connected in series or in parallel.

[0044] It should be noted that the battery cell 111 provided in this application embodiment includes either a full-cell battery or a sliced ​​battery. A sliced ​​battery refers to a battery cell formed by cutting a complete full-cell battery. The cutting process includes: laser grooving + cutting process and thermal stress battery force distribution process. Sliced ​​batteries can improve the power generation of the battery string composed of battery cells by reducing resistance loss. Sliced ​​batteries include at least one of half-cell, three-cell, and four-cell. Of course, the battery cell 111 can also be selected from other types, and this application does not limit this.

[0045] In some embodiments, the solar cell 111 provided in this application can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, a multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell. In some embodiments, the solar cell 111 includes, but is not limited to, any one of PERC (Passivated Emitter and Rear Cell), TOPCon (Tunnel Oxide Passivated Contact), HJT (Heterojunction), or BC (Back Contact) cells. By energizing and irradiating the solar cell 111 with ultraviolet light, the output power of the photovoltaic module 100 fabricated from the solar cell 111 can be increased. Preferably, the solar cell 111 is selected from PERC monocrystalline cells or TOPCon cells.

[0046] For PERC cells, along their thickness direction, the PERC cell sequentially includes a front electrode, a front surface passivation layer, an emitter, a P-type substrate silicon layer, a local aluminum back field, a back electrode, and a back passivation layer. PERC cells employ back passivation technology, which enhances light reflection within the silicon substrate, reduces the recombination rate on the back side, and thus improves the efficiency of the PERC cell.

[0047] For TOPCon cells, along their thickness direction, the TOPCon cell sequentially includes a front electrode, a front surface passivation layer, an emitter, an N-type substrate silicon layer, a diffused doped layer, an ultrathin oxide layer, a doped conductive layer, a back passivation layer, and a back electrode. The back of the cell consists of an ultrathin oxide layer (1nm–2nm) and a layer of polycrystalline silicon containing doped elements, which together form a passivation contact structure. This structure can block minority carrier hole recombination, increasing the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while blocking minority carrier hole recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon films causes band bending on the silicon wafer surface, resulting in a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the cell's open-circuit voltage and short-circuit current, thereby increasing the cell's conversion efficiency.

[0048] For an HJT cell, along its thickness direction, it sequentially includes a front electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type monocrystalline silicon substrate, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back electrode. The HJT cell utilizes an N-type monocrystalline silicon substrate and the amorphous silicon films on both sides to form a double-sided passivation structure, providing dual passivation for surface defects on the silicon substrate, increasing the open-circuit voltage, and contributing to the high photoelectric conversion efficiency of the cell.

[0049] For BC cells, such as interdigitated back contact (IBC) cells, along their thickness direction, an IBC cell sequentially includes a front antireflection layer, a front field region, a silicon substrate, an emitter, and a back field region forming an alternating layer structure, a passivation layer, a back antireflection layer, and alternating first and second electrodes. IBC cells utilize ion implantation technology to obtain P-regions and N-regions with good uniformity and precisely controllable junction depth. The absence of grid lines on the front of the cell eliminates light-blocking current loss from the electrodes, maximizing the utilization of incident photons. Due to the back contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front surface recombination rates and surface reflection.

[0050] Typically, the solar cells 111 exist in the photovoltaic module 100 in the form of a string of cells 11 or a group of cells (a group of cells is composed of multiple strings of cells 11 connected in series or in parallel). The following explanation only takes the example of energizing the string of cells 11 and irradiating it with ultraviolet light.

[0051] Figure 2 A schematic diagram of the structure for energizing and irradiating the battery string 11 with ultraviolet light is shown, as follows. Figure 2 As shown, the battery string 11 is laid flat, and a positive electrode 10 and a negative electrode 20 are connected to the battery cells 111 at both ends of the battery string 11, respectively, so that the battery string 11 is supplied with positive direct current. Several ultraviolet light irradiation devices 30 are used to irradiate each battery cell 111 in the battery string 11 with ultraviolet light; alternatively, a single ultraviolet light irradiation device 30 can be used to irradiate the entire battery string 11. This application does not impose any limitations on this method. In this embodiment, the positive electrode 10 and half of the secondary electrode are made of conductive materials, such as copper or aluminum. The ultraviolet light irradiation device 30 can be, for example, an ultraviolet lamp.

[0052] In some implementations, the two ends of the battery string 11 are first energized, and then the battery cells 111 in the battery string 11 are irradiated with ultraviolet light.

[0053] In some implementations, the battery cells 111 in the battery string 11 are first irradiated with ultraviolet light, and then the battery is powered on.

[0054] In some embodiments, while the battery string 11 is energized, the battery cells 111 in the battery string 11 are irradiated with ultraviolet light.

[0055] This application does not restrict the order of energizing and ultraviolet irradiation, only requiring that the overlap time between energizing and irradiating the battery string 11 is greater than or equal to 0.5 s. In this way, energizing can activate the hydrogen (H) in the battery cells 111 of the battery string 11, and ultraviolet irradiation removes excess Si-H bonds from the battery cells 111, thereby optimizing the passivation performance of the battery cells 111 and improving the output power of the photovoltaic module 100 composed of the battery string 11. Preferably, energizing the battery string 11 first, followed by ultraviolet irradiation, activates more hydrogen (H) in the battery cells 111, which is beneficial for breaking more Si-H bonds in the battery cells 111 under ultraviolet irradiation, improving the quality of the battery cells 111. Furthermore, when energizing the battery string 11, the temperature of the battery cells 111 increases, which can shorten the ultraviolet irradiation time of the battery string 11 and improve the pretreatment effect of the battery string 11.

[0056] In some embodiments, the overlap time between energizing the battery string 11 and irradiating it with ultraviolet light is 0.5s to 10s, specifically 0.5s, 1s, 3s, 5s, 8s, or 10s. Within the above-mentioned range, it is possible to effectively improve the quality of the battery cell 111, save resources, reduce manufacturing costs, and improve efficiency.

[0057] In some embodiments, the current energizing the battery string 11 is a forward current, meaning the direction of the current energizing the battery cells 111 within the battery string 11 is the same as the diffusion direction of electrons in the battery cells 111. Thus, the current flow direction in the battery cells 111 is consistent with the natural current flow direction during normal operation. Preferably, the current energizing the battery string 11 is a forward direct current.

[0058] In some implementations, the current energized to the battery string 11 is 2 to 5 times the short-circuit current of a single battery cell 111, specifically 2, 3, 4, or 5 times. If the energizing current is greater than 5 times the short-circuit current of a single battery cell 111, erosion of the contact points or melting of the solder strips can easily occur in the contact area between the electrode (positive electrode 10 or negative electrode 20) and the battery cell 111, damaging the battery cell or battery string. If the energizing current is less than 2 times the short-circuit current of a single battery cell 111, the heating efficiency of the battery cell 111 is low, the processing time is long, and the production capacity is affected. It can be understood that the short-circuit current (Isc) of the battery cell 111 refers to the maximum current that the battery cell 111 can output when the positive and negative terminals of the solar cell 111 or battery module are directly connected (short-circuited). For example, taking a 182 half-cell battery as an example, the short-circuit circuit Isc of a 182 half-cell battery is approximately 6.8A, and its corresponding energizing current is 13.6A to 34A.

[0059] In some implementations, the energizing time is 0.3s to 15s, specifically 0.3s, 0.5s, 1s, 3s, 5s, 10s, or 15s.

[0060] In some embodiments, the wavelength of ultraviolet light irradiation is 280nm to 400nm, specifically 280nm, 300nm, 350nm, 380nm or 400nm, etc. Within the above wavelength range, the Si-H bonds in the solar cell 111 are easily damaged by ultraviolet light and break, thereby changing the valence state of some H in the solar cell 111.

[0061] In some embodiments, when the battery cells 111 in the battery string 11 are irradiated with ultraviolet light, the entire surface of the battery string 11 is irradiated uniformly, which is beneficial to improving the overall quality of the battery string 11. Preferably, the irradiation wavelength of ultraviolet light on the battery cells 111 in the same battery string 11 can be the same or different.

[0062] In some embodiments, the battery cell 111 includes a front side and a back side disposed opposite to each other. The front side is the light-receiving surface of the battery cell 111, and the back side is the back-lighting surface of the battery cell 111. Ultraviolet light irradiation is selectively applied to the front side of the battery cell 111.

[0063] In some embodiments, the power of ultraviolet light irradiation is 100 W / m. 2 ~500W / m 2 Specifically, it can be 100W / m 2 200W / m 2 300W / m 2 400W / m 2 Or 500W / m 2Within the aforementioned limits, it is indicated that ultraviolet light irradiation has a suitable light intensity, which has sufficient energy to break Si-H bonds without affecting other bonds in the solar cell 111, thereby improving the passivation performance of the solar cell 111.

[0064] In some implementations, the duration of ultraviolet irradiation is 0.1s to 20s, specifically 0.1s, 0.5s, 1s, 3s, 5s, 10s, 15s, 18s, or 20s.

[0065] S200, a first packaging structure 2 and a second packaging structure 3 are provided. The first packaging structure 2 includes a first cover plate 21 and a first packaging layer 22, and the second packaging structure 3 includes a second cover plate 31 and a second packaging layer 32.

[0066] In some embodiments, the first encapsulation layer 22 may be made of at least one of POE (Polyolefin Elastomer) and EVA (ethylene-vinyl acetate copolymer). The first encapsulation layer 22 is made of a transparent material, allowing incident light from the front to pass through smoothly. The first encapsulation layer 22 protects the solar cells 111 in the pre-treated layer 1 from environmental factors such as moisture, oxygen, and ultraviolet radiation, extending the lifespan of the solar cells 111. It also provides some shock absorption and cushioning, which helps to enhance the structural strength and lifespan of the photovoltaic module 100.

[0067] In some embodiments, a second encapsulation layer 32 is disposed on the back side of the pretreated sheet 1. The material of the second encapsulation layer 32 can be at least one of POE (Polyolefin Elastomer) and EVA (ethylene-vinyl acetate copolymer). The second encapsulation layer 32 is made of a transparent material, allowing incident light from the back side to pass through smoothly. The second encapsulation layer 32 can protect the solar cells 111 in the pretreated sheet 1 from environmental factors such as moisture, oxygen, and ultraviolet radiation, extending the service life of the solar cells 111. It can also play a certain role in shock absorption and buffering, which is beneficial to enhancing the structural strength and service life of the photovoltaic module 100.

[0068] This application does not limit the specific preparation method of the first encapsulation layer 22 and the second encapsulation layer 32. For example, the first encapsulation layer 22 and the second encapsulation layer 32 can be formed by roll forming process.

[0069] In some embodiments, the first cover plate 21 is usually made of light-transmitting coated glass, but it can also be made of other materials. The specific material of the first cover plate 21 is not specifically limited in this application embodiment, as long as it can ensure a certain light transmittance so that the solar cell string 11 can absorb external light, and has a certain structural strength to protect the pre-treated sheet 1 set on the backlight side of the first cover plate.

[0070] In some embodiments, the thickness of the first cover plate 21 is 3.2mm to 10mm. Specifically, the thickness of the first cover plate 21 can be 3.2mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, and 10mm, etc. The light transmittance of the first cover plate 21 is required to be above 90%.

[0071] In some embodiments, the material of the second cover plate 31 can be light-transmitting coated glass, or it can be selected from at least one of poly(TPT) backsheet, TPE backsheet, KPK backsheet, KPC backsheet, CPC backsheet, and CPE backsheet. The second cover plate 31 is made from purchased finished backsheet material, which is then cut into suitable shapes and sizes using an offline cutting machine in the workshop, and the cutting waste is collected for later use. It is understood that when the material of the second cover plate 31 is light-transmitting coated glass, the photovoltaic module 100 of this application is a double-glass photovoltaic module. When the material of the second cover plate 31 is selected from at least one of poly(TPT) backsheet, TPE backsheet, KPK backsheet, KPC backsheet, CPC backsheet, and CPE backsheet, the photovoltaic module 100 of this application is a single-glass photovoltaic module.

[0072] In some embodiments, the second cover plate 31 has a three-layer composite structure, which consists of an EV (random copolymer of ethylene and vinyl acetate) layer, a PET (polyethylene terephthalate) layer, and a fluorine layer from the front to the back of the solar cell string 11. The fluorine layer has strong weather resistance and durability and is set on the outermost layer of the photovoltaic module 100. The PET layer is set in the middle and mainly provides mechanical properties, electrical insulation properties, and barrier properties. The EV layer is mainly to ensure the reliable connection between the second cover plate 31 and the second encapsulation layer 32.

[0073] S300, the first cover plate 21, the first encapsulation layer 22, the pre-treated sheet layer 1, the second encapsulation layer 32 and the second cover plate 31 are stacked and laminated to obtain the photovoltaic module 100.

[0074] In some embodiments, the stacking sequence includes two types: the first type is to place the first cover plate 21 on the platform first, and then place the first encapsulation layer 22, the battery string 11, the second encapsulation layer 32 and the second cover plate 31 in sequence to assemble a photovoltaic module 100; the second type is to place the second cover plate 31 on the platform first, and then place the second encapsulation layer 32, the battery string 11, the first encapsulation layer 22 and the first cover plate 21 in sequence.

[0075] Lamination is a process of bonding and fusing the various components of a photovoltaic module 100 together under specific temperature, pressure, and vacuum conditions to protect the cell string 11. The laminated photovoltaic module 100 is placed in a laminator, and air is extracted from the photovoltaic module 100 by vacuuming. Then, heating is applied to melt and solidify the first encapsulation layer 22 and the second encapsulation layer 32, bonding the cell string 11, the first cover plate 21, and the second cover plate 31 together. Finally, the photovoltaic module 100 is cooled and removed.

[0076] In some embodiments, the lamination process includes a framing step, in which the laminated module is installed within a frame. The frame serves to support and protect the entire solar panel, thus obtaining the photovoltaic module 100 of this application. In some embodiments, the photovoltaic module 100 can also be connected to an external photovoltaic support structure via the frame, and multiple photovoltaic modules 100 can be interconnected to form a photovoltaic power station.

[0077] In some implementations, the frame can be made of aluminum alloy or stainless steel. When aluminum alloy is used, the frame has excellent strength and corrosion resistance.

[0078] The photovoltaic module 100 fabrication method provided in this application pre-treats the solar cell 111 by energizing and irradiating it with ultraviolet light after the solar cell 111 structure is fabricated and before it is fabricated into a photovoltaic module 100. This can improve the passivation performance of the solar cell 111, increase the open-circuit voltage and fill factor of the solar cell 111, and thus increase the output power of the photovoltaic module 100 composed of the solar cell 111.

[0079] This application also provides a photovoltaic module 100 prepared by the above-described preparation method. Figure 3 A schematic diagram of the structure of a photovoltaic module provided in this application is shown, such as... Figure 3 As shown, it includes:

[0080] The pre-treated sheet 1 includes at least one battery cell 111, and the pre-treated sheet 1 has opposing first and second surfaces;

[0081] A first encapsulation structure 2 is located on the first surface of the pre-processed sheet 1. The first encapsulation structure 2 includes a first encapsulation layer 22 and a first cover plate 21, with the first encapsulation layer 22 located between the pre-processed sheet 1 and the first cover plate 21.

[0082] The second encapsulation structure 3 is located on the second surface of the pre-processed sheet 1. The second encapsulation structure 3 includes a second encapsulation layer 32 and a second cover plate 31. The second encapsulation layer 32 is located between the pre-processed sheet 1 and the second cover plate 31.

[0083] In the above scheme, the photovoltaic module 100 of this application is pretreated by energizing and irradiating with ultraviolet light after the solar cell 111 is prepared, so that the solar cell 111 has excellent passivation performance, thereby improving the output power of the photovoltaic module 100 composed of the solar cell 111.

[0084] Example

[0085] (1) 450 182 solar cells (182 solar cells refer to rectangular monocrystalline silicon solar cells with a side length of 182 mm) are wired together to obtain a solar cell string.

[0086] (2) Power is applied to both ends of the battery string using a positive direct current of 25A. Simultaneously, the battery cells within the string are irradiated with 365nm ultraviolet light at a power of 300W / m. 2 The pretreated sheet was obtained by applying power and irradiating it with ultraviolet light for 2 seconds.

[0087] (3) The pre-treated sheets, glass, EVA film and backsheet obtained in step (2) are stacked according to the photovoltaic module design to form a stacked structure. Then, the stacked structure is laminated by a laminator to prepare a photovoltaic module.

[0088] Comparative Example 1

[0089] The difference from the embodiment is that step (2) is not performed.

[0090] Comparative Example 2

[0091] The difference from the embodiment is that step (2) is: energize both ends of the battery string, the current is positive DC, the current is 25A, the energizing time is 2s, and a pre-processed sheet is obtained.

[0092] Comparative Example 3

[0093] The difference from the embodiment is that step (2) involves irradiating the battery cells in the battery string with 365nm ultraviolet light, and the power of the ultraviolet light is 300W / m. 2 The ultraviolet light irradiation time was 2 seconds to obtain the pretreated film.

[0094] Five groups of photovoltaic modules prepared according to the above embodiments and comparative examples 1 to 3 were prepared and their performance was tested as follows. The test results are shown in Table 1. The test data are the average values ​​of the five groups of photovoltaic modules.

[0095] Table 1. Performance determination of photovoltaic modules prepared in the examples and comparative examples

[0096]

[0097]

[0098] The cell efficiency of the pretreated cells in the embodiments and Comparative Examples 1 to 3 was tested respectively. The cell efficiency of the cell in Comparative Example 1 was 26.04%, and the cell efficiency of the cell in the embodiments was 26.08%, an improvement of 0.4%. As shown in Table 1, compared with the conventional photovoltaic module (Comparative Example 1), the photovoltaic module prepared in this application has a 0.02% increase in open-circuit voltage, a 0.12% increase in fill factor, and a 0.8W increase in module power. The cell in Comparative Example 2 was only energized, and its open-circuit voltage was slightly higher than that of Comparative Example 1, but the short-circuit current, fill factor, and module power were all lower. The cell in Comparative Example 3 was only irradiated with ultraviolet light, and its fill factor was slightly higher than that of Comparative Example 1, and its open-circuit voltage was the same as that of Comparative Example 1, but the short-circuit current and module power were both lower. Therefore, this application, by pre-energizing and irradiating the prepared solar cells with ultraviolet light before preparing photovoltaic modules, can reduce cell recombination, improve the passivation performance of the solar cells, increase the fill factor, and effectively improve the output power of photovoltaic modules without changing the cell structure.

[0099] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a photovoltaic module, characterized in that, Includes the following steps: Provide at least one solar cell, pre-treat the solar cell to obtain a pre-treated layer, the pre-treatment including first energizing the solar cell and then irradiating it with ultraviolet light, the energizing time being 0.3s to 15s, the energizing current being 2 to 5 times the short-circuit current of a single solar cell; A first packaging structure and a second packaging structure are provided, wherein the first packaging structure includes a first cover plate and a first packaging layer, and the second packaging structure includes a second cover plate and a second packaging layer; The first cover plate, the first encapsulation layer, the pre-treated sheet layer, the second encapsulation layer, and the second cover plate are stacked and laminated to obtain a photovoltaic module.

2. The preparation method according to claim 1, characterized in that, The direction of the current flowing through the battery cell is the same as the direction of electron diffusion in the battery cell.

3. The preparation method according to claim 1, characterized in that, The number of solar cells is at least two, and the process includes welding at least two solar cells before pre-processing them.

4. The preparation method according to claim 1, characterized in that, The wavelength of the ultraviolet light is 280nm to 400nm.

5. The preparation method according to claim 1, characterized in that, The power of the ultraviolet light irradiation is 100W / m 2 ~500W / m 2 .

6. The preparation method according to claim 1, characterized in that, The overlap time between the battery cell being powered on and irradiated with ultraviolet light is greater than or equal to 0.5 s.

7. The preparation method according to claim 1, characterized in that, The battery cell includes at least one of the following: full cell, half cell, three-part cell, and four-part cell.

8. A photovoltaic module, characterized in that, The photovoltaic module is prepared by the method described in any one of claims 1 to 7.

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