A battery cell and photovoltaic module

Abstract

The embodiment of the present application provides a cell and a photovoltaic module, wherein the cell includes a cell body and a reflective layer. The cell body includes a light-receiving surface and a backlight surface, and along the thickness direction of the cell body, the light-receiving surface and the backlight surface are located on opposite sides of the cell body. The cell body includes a substrate and a first passivation layer, and the first passivation layer is located on the side of the substrate facing the backlight surface. The reflective layer includes a first adhesive film layer and reflective particles, wherein the first adhesive film layer is arranged on the side of the first passivation layer away from the substrate, and the reflective particles are arranged on the cell body through the first adhesive film layer. By arranging a reflective layer on the backlight side of the cell body, the light passing through the cell body can be reflected so that the light can be transmitted again in the cell body, which is beneficial to increase the total transmission distance of the light in the cell body, thereby improving the utilization rate of the light and reducing the optical loss, thereby improving the overall efficiency of the cell, and better meeting the actual use requirements.

Description

Technical Field

[0001] The present application relates to the photovoltaic field, and in particular to a solar cell and a photovoltaic module. Background Art

[0002] With the development of technology, photovoltaic devices such as photovoltaic modules are increasingly used in people's daily lives. Photovoltaic modules include cells, which can absorb light and convert light energy into electrical energy. Usually, the main material of cells is silicon. Photons in the infrared band of light have a long absorption depth, and the thickness of the cell is limited. Therefore, during the use of photovoltaic modules, a large number of infrared photons cannot be absorbed by the cell, resulting in large optical losses. The cell has a low absorption efficiency for light, resulting in a low conversion efficiency of the cell. Summary of the invention

[0003] The embodiments of the present application provide a solar cell and a photovoltaic module for improving the conversion efficiency of the solar cell.

[0004] The present application provides a battery cell, the battery cell comprising:

[0005] A battery body, comprising a substrate and a first passivation layer;

[0006] A reflective layer, which is arranged on one side of the battery body along the thickness direction of the battery body;

[0007] Among them, the battery body includes a light-receiving surface and a backlight surface. Along the thickness direction of the battery body, the light-receiving surface and the backlight surface are located on opposite sides of the battery body. The first passivation layer is located on the side of the substrate close to the backlight surface. The reflective layer includes a first adhesive film layer and reflective particles. The first adhesive film layer is arranged on the side of the first passivation layer away from the substrate, and the reflective particles are arranged on the battery body through the first adhesive film layer.

[0008] In a possible implementation manner, the thickness of the first adhesive film layer is 5 nanometers to 100 nanometers, and / or the refractive index of the first adhesive film layer is 1.3 to 1.7.

[0009] In a possible implementation manner, the first adhesive film layer is a resin film layer.

[0010] In a possible implementation, the diameter of the reflective particles is 50 nanometers to 800 nanometers, and / or the refractive index is 1.2 to 2.

[0011] In one possible embodiment, the reflective particles include at least one of chromium oxide, antimony oxide, titanium oxide, cobalt oxide, chromium nitride, antimony nitride, titanium nitride, cobalt nitride, chromium oxide nitrogen, antimony oxide nitrogen, titanium oxide nitrogen, and cobalt oxide nitrogen.

[0012] In a possible implementation, the first passivation layer includes a first region and a second region, the first region is used to arrange the gate line, and the reflective layer is arranged in the second region.

[0013] In a possible implementation, in the projection along the thickness direction of the battery cell, the total area of ​​the second region is a, the total area of ​​the reflective particles is b, and the following condition is satisfied: 0.1a≤b≤a.

[0014] In a possible implementation manner, along the thickness direction of the battery cell, the thickness of the battery cell is 50 micrometers to 300 micrometers.

[0015] In a possible implementation, the battery cell includes a light-transmitting layer, which is located on the side of the substrate facing the light-receiving surface, and includes a second adhesive film layer and light-converting particles, which are disposed on the battery body through the second adhesive film layer.

[0016] An embodiment of the present application further provides a photovoltaic module, the photovoltaic module comprising a battery cell, and the battery cell is any of the above battery cells.

[0017] The embodiment of the present application provides a cell and a photovoltaic module, the cell includes a cell body and a reflective layer, the reflective layer is located on one side of the cell body along the thickness direction of the cell body. The cell body includes a light-receiving surface and a backlight surface, and along the thickness direction of the cell body, the light-receiving surface and the backlight surface are located on opposite sides of the cell body. Usually, along the gravity direction, the light-receiving surface is located above the backlight surface. The cell body includes a substrate and a first passivation layer, and the first passivation layer is located on the side of the substrate facing the backlight surface. The reflective layer includes a first adhesive film layer and reflective particles, the first adhesive film layer is arranged on the side of the first passivation layer away from the substrate, and the reflective particles are arranged on the cell body through the first adhesive film layer. By arranging a reflective layer on the backlight side of the cell body, the light passing through the cell body can be reflected so that the light can be transmitted again in the cell body, which is conducive to increasing the total transmission distance of the light in the cell body, thereby improving the utilization rate of the light, reducing optical losses, and then improving the overall efficiency of the cell, which is more in line with actual usage needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A schematic diagram of a first embodiment of a battery cell provided in an embodiment of the present application;

[0020] Figure 2The SEM image of the cell with a reflective layer provided in the embodiment of the present application;

[0021] Figure 3 A schematic diagram of a second embodiment of a battery cell provided in an embodiment of the present application;

[0022] Figure 4 A schematic diagram of a third embodiment of a battery cell provided in an embodiment of the present application;

[0023] Figure 5 The SEM image of the cell with a light-transmitting layer provided in the embodiment of the present application;

[0024] Figure 6 This is a schematic diagram of wavelength-fluorescence signal intensity provided in an embodiment of the present application.

[0025] Reference numerals

[0026] 1-Battery body;

[0027] 11 - base;

[0028] 12- first passivation layer;

[0029] 13- second passivation layer;

[0030] 14-grid line;

[0031] 2-Reflective layer;

[0032] 21- first adhesive film layer;

[0033] 22-Reflective particles;

[0034] 3-light-transmitting layer;

[0035] 31- second adhesive film layer;

[0036] 32-Light-to-particles. DETAILED DESCRIPTION

[0037] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0038] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0039] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0040] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] like Figure 1 As shown, an embodiment of the present application provides a battery cell and a photovoltaic module, wherein the battery cell includes a battery body 1 and a reflective layer 2, wherein the reflective layer 2 is located on one side of the battery body 1 along the thickness direction of the battery body 1. The battery body 1 includes a light-receiving surface and a backlight surface, wherein the light-receiving surface and the backlight surface are located on opposite sides of the battery body 1 along the thickness direction of the battery body 1. Usually, along the gravity direction, the light-receiving surface is located above the backlight surface. The battery body 1 includes a substrate 11 and a first passivation layer 12, wherein the first passivation layer 12 is located on the side of the substrate 11 facing the backlight surface. The reflective layer 2 includes a first adhesive film layer 21 and reflective particles 22, wherein the first adhesive film layer 21 is disposed on the side of the first passivation layer 12 away from the substrate 11, and the reflective particles 22 are disposed on the battery body 1 through the first adhesive film layer 21.

[0042] In the embodiment of the present application, a reflective layer 2 is provided on the backlight side of the battery body 1 for reflecting light, so that the reflective layer 2 can reflect the light passing through the battery body 1, so that the light can propagate again to the side where the battery body 1 is located, thereby extending the propagation distance of the light in the battery body 1, which is beneficial to improving the battery body 1 to better absorb infrared photons, thereby reducing optical losses and improving the short-circuit current and conversion efficiency of the battery body 1.

[0043] During processing, the battery body 1 may be processed first, and after the processing of the battery body 1 is completed, the reflective layer 2 is arranged on the backlight side of the battery body 1. The battery body 1 and the reflective layer 2 may be relatively independent structures, and such a design may not require adjustment of the structure of the battery body 1, thereby reducing damage to structures such as the first passivation layer 12, reducing the difficulty of setting the reflective layer 2, and reducing the impact on the battery body 1, thereby facilitating improving the efficiency of the battery body 1 and meeting actual usage requirements.

[0044] Compared with improving the reflective effect of the back side of the battery cell by adjusting the structure of the first passivation layer 12, since the first passivation layer 12 needs to take into account both the reflective effect and the passivation effect during production, not only is the material requirement high, but the processing difficulty is also relatively large. Usually, the material of the first passivation layer 12 is silicon oxynitride, silicon oxide and other materials. These materials have good passivation performance, but the reflection ability of infrared light is poor. If the infrared reflection layer is directly integrated into the battery body 1, it is necessary to adjust the material and structure of the first passivation layer 12 of the battery body 1, resulting in increased production costs and reduced production efficiency. Therefore, in the solution provided in the embodiment of the present application, after the battery body 1 is processed, an additional reflective layer 2 can be set on the backlight side of the battery body 1 to reflect infrared light. Infrared light can be reflected without affecting the structure of the battery body 1. The operation is simple during processing, and the passivation effect and other performance of the battery body 1 are less affected, which is more in line with actual use requirements.

[0045] In a possible implementation manner, the thickness of the first adhesive film layer 21 is 5 nanometers to 100 nanometers, and the refractive index of the first adhesive film layer 21 is 1.3 to 1.7.

[0046] The thickness of the first film layer can be 5 nanometers, 10 nanometers, 15 nanometers, 20 nanometers, 25 nanometers, 30 nanometers, 35 nanometers, 40 nanometers, 45 nanometers, 50 nanometers, 55 nanometers, 60 nanometers, 65 nanometers, 70 nanometers, 75 nanometers, 80 nanometers, 85 nanometers, 90 nanometers, 95 nanometers, 100 nanometers, etc. The refractive index of the first adhesive film layer 21 can be 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, etc.

[0047] When the thickness of the first adhesive film layer 21 is less than 5 nanometers, the thickness of the first adhesive film layer 21 is too thin, the bonding ability is reduced, and the reflective particles are easily removed, resulting in a reduction in the effect of the reflective layer 2. When the thickness of the first adhesive film layer 21 exceeds 100 nanometers, the thickness of the first adhesive film layer 21 is too thick, and the transmission distance of the light in the first adhesive film layer 21 increases, which will cause the loss of light in the propagation process to increase. When the refractive index of the first adhesive film layer 21 is less than 1.3, the material requirements for the first adhesive film layer 21 are high, resulting in increased costs. When the refractive index of the first adhesive film layer 21 is higher than 1.7, it will affect the propagation speed of light in the reflective layer 2, thereby affecting the conversion efficiency, resulting in an increase in the energy loss of light in the transmission process. When the refractive index of the first adhesive film layer 21 is too large or too small, it will affect the absorption of light by the battery body 1.

[0048] In a possible implementation manner, the first adhesive film layer 21 may be a resin film layer.

[0049] The resin film layer has good durability and oxidation resistance, and can also protect the surface of the battery body 1 , reduce the impact of bumps and scratches on the battery body 1 , and reduce the possibility of damage to the battery body 1 .

[0050] The reflective layer 2 may be provided by, but not limited to, spin coating, spray coating, or scraping coating. When providing the reflective layer 2, reflective particles 22 may be added to the resin material, and the mixture of the resin material and the reflective particles 22 may be provided on the backlight side of the battery body 1.

[0051] like Figure 2 As shown, Figure 2 This is a SEM image of a cell with a reflective layer provided in an embodiment of the present application. In a possible implementation, the diameter of the reflective particles 22 is 50 nanometers to 800 nanometers, and the refractive index is 1.2 to 2.

[0052] The method for measuring the diameter of the reflective particles 22 includes, but is not limited to, randomly selecting 10 reflective particles 22 in the SEM image, calculating the average diameter, and obtaining the average diameter of the reflective particles 22. The average diameter of the reflective particles 22 can be between 50 nanometers and 800 nanometers. Alternatively, X reflective particles 22 with larger diameters and Y reflective particles 22 with smaller diameters can be randomly selected from the SEM image by visual inspection, and the diameters of the selected reflective particles 22 are measured respectively. When the diameters of the selected reflective particles 22 are within the range of 50 nanometers to 800 nanometers, the reflective particles 22 meet the requirements. The values ​​of X and Y can be 2, 3, 4, 5, 6, 7, 8, 9, etc., respectively.

[0053] The diameter of the reflective particles 22 can be 50 nanometers, 100 nanometers, 150 nanometers, 200 nanometers, 250 nanometers, 300 nanometers, 350 nanometers, 400 nanometers, 450 nanometers, 500 nanometers, 550 nanometers, 600 nanometers, 650 nanometers, 700 nanometers, 750 nanometers, 800 nanometers, etc. The refractive index can be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, etc.

[0054] When the diameter of the reflective particle 22 is less than 50 nanometers, the diameter of the reflective particle 22 is too small, which will increase the difficulty of arranging the reflective particle 22. During preparation, the difficulty of preparation increases, and it is difficult to control the uniformity of the reflective particle 22. In addition, the diameter difference between the reflective particles 22 will be too large. When reflecting light, the light path difference will be large, which will affect the radiation effect. When the diameter of the reflective particle 22 is greater than 800 nanometers, the diameter of the reflective particle 22 is too large, which has a greater impact on the difficulty of setting, resulting in increased processing difficulty. When the refractive index of the reflective particle 22 is less than 1.2, the material requirements for the reflective particle 22 are high, and the realization is difficult and the cost is high. When the refractive index of the reflective particle 22 is greater than 2.0, it will affect the propagation speed of the light, resulting in an increase in the loss of the light during the propagation process. Moreover, when the refractive index is too large or too small, it will affect the absorption of light. The refractive index between 1.2 and 2.0 can be beneficial to the reflective layer 2 for reflecting infrared light, improve the absorption efficiency of the battery body 1 for light, and better meet the actual use needs.

[0055] In one possible embodiment, the reflective particles 22 include at least one of chromium oxide, antimony oxide, titanium oxide, cobalt oxide, chromium nitride, antimony nitride, titanium nitride, cobalt nitride, chromium oxide nitrogen, antimony oxide nitrogen, titanium oxide nitrogen, and cobalt oxide nitrogen.

[0056] In this way, light can be reflected, which is beneficial to improve the light absorption efficiency of the battery body 1, so as to improve the conversion rate of the battery body 1 and better meet the actual use requirements.

[0057] like Figure 3 As shown, in a possible implementation, the first passivation layer 12 includes a first region and a second region, the first region is used to arrange the gate line 14, and the reflective layer 2 is arranged in the second region.

[0058] By arranging the reflective layer 2 in the second region, the influence of the reflective layer 2 on the electrical performance of the grid lines 14 can be reduced. Since the first region can reflect light through the grid lines 14, the reflective effect is small when the reflective layer 2 is located on the side of the grid lines 14 away from the substrate 11, so it is not necessary to arrange it in the first region.

[0059] In a possible implementation, the width of the first region may be greater than the width of the grid line 14. Such a design can allow a certain distance between the reflective layer 2 and the grid line 14, thereby reducing the possibility of the reflective layer 2 covering the grid line 14, reducing the difficulty of processing, and reducing the influence of the reflective layer 2 on the contact performance of the grid line 14.

[0060] During processing, the grid lines 14 may be arranged on the battery body 1 first, and then the reflective layer 2 may be arranged. When the reflective layer 2 is arranged, the grid lines 14 may be shielded to reduce the possibility that the reflective layer 2 is arranged in the first area.

[0061] In this way, the processing flow of the battery body 1 does not need to be adjusted, and the reflective layer 2 can be set after the processing of the battery body 1 is completed. In the scheme of setting the reflective layer 2 first and then setting the grid lines 14, since screen printing, sintering and other operations are required when setting the grid lines 14, they need to be performed under high temperature conditions. If the reflective layer 2 is set first and then the grid lines 14 are set, the first adhesive film layer 21 will be melted during the arrangement of the grid lines 14, which will damage the structure and stability of the reflective layer 2, thereby affecting the quality of the reflective layer 2, resulting in a decrease in the reflective ability, and further affecting the efficiency of the battery body 1.

[0062] In a possible implementation, in the projection along the thickness direction of the battery cell, the total area of ​​the second region is a, the total area of ​​the reflective particles 22 is b, and a and b satisfy: 0.1a≤b≤a.

[0063] The total area of ​​the reflective particles 22 can account for 10% to 100% of the total area of ​​the second region. In a possible embodiment, the total area of ​​the reflective particles 22 can account for 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc. of the total area of ​​the second region.

[0064] When the area proportion of the reflective particles 22 is less than 10%, there are too few reflective particles 22, the light-emitting effect of the reflective layer 2 is poor, and the effect of improving the absorption efficiency of the battery body 1 is poor. Therefore, the reflective particles 22 need to cover the second area as much as possible, so that the reflective layer 2 can better reflect the light passing through the battery body 1, thereby extending the transmission distance of the light in the battery body 1, which is conducive to the battery body 1 to better absorb the light, improve the efficiency of the battery body 1, and better meet the actual use needs.

[0065] In a possible implementation, along the thickness direction of the cell, the thickness of the cell is 50 micrometers to 300 micrometers. The thickness of the cell may be 50 micrometers, 70 micrometers, 90 micrometers, 110 micrometers, 130 micrometers, 150 micrometers, 170 micrometers, 190 micrometers, 210 micrometers, 230 micrometers, 250 micrometers, 270 micrometers, 290 micrometers, 300 micrometers, etc.

[0066] The solution provided in the embodiment of the present application has no significant change compared to the conventional thickness of the battery body 1. The dimensions of the first adhesive film layer 21 and the reflective particles 22 in the thickness direction are nanometer-level, while the dimensions of the grid lines 14 in the thickness direction of the battery body 1 are micrometer-level, so the dimensions of the reflective layer 2 in the thickness direction of the battery cell are smaller than the dimensions of the grid lines 14 in the thickness direction. Since the reflective layer 2 is arranged in the second area of ​​the battery body 1, the solution provided in the embodiment of the present application can improve the efficiency of the battery body 1 without increasing the thickness of the battery body 1, which is conducive to reducing costs and is more in line with actual usage requirements.

[0067] The material of the substrate 11 of the battery body 1 is usually silicon, and the battery body 1 is obtained after processing. In the light, the photons in the infrared band have a longer absorption depth, and the thickness of the battery body 1 is limited, and it is impossible to absorb all the photons in the infrared band. When the absorption efficiency of the battery body 1 is improved by increasing the thickness of the battery body 1, it not only leads to an increase in cost, but also increases the volume of the battery body 1, which in turn leads to an increase in the volume of the photovoltaic module. In the scheme provided in the embodiment of the present application, by setting a reflective layer 2 on the backlight side of the battery body 1, the light passing through the battery body 1 can be reflected, so that the light re-enters the battery body 1, so that the battery body 1 can absorb the light again. In this way, the transmission distance of the light in the battery body 1 can be approximately twice the thickness of the battery body 1, thereby greatly improving the absorption efficiency of the battery body 1 for photons in the infrared band, improving the utilization efficiency of the battery body 1 for infrared light, and reducing optical losses.

[0068] Taking TOPCon battery as an example, the data shown in Table 1 below are obtained by testing TOPCon battery:

[0069] Table 1

[0070] TOPCon Battery Voc(V) Isc(A) FF(%) Eta(%) Before applying reflective layer 0.7361 13.897 85.46 26.11 After coating the reflective layer 0.7360 13.975 85.45 26.25

[0071] In the table, Voc is the open circuit voltage, Isc is the short circuit current, FF is the fill factor, and Eta is the efficiency. From the data in Table 1, it can be seen that by setting the reflective layer 2 in the TOPCon battery, the short circuit current of the TOPCon battery is increased by 78mA and the conversion efficiency is increased by 0.14%. By setting the reflective layer 2 in the TOPCon battery, the short circuit current and efficiency of the battery body 1 can be increased, thereby improving the performance of the battery body 1.

[0072] It should be noted here that the solution provided in the embodiment of the present application can be applied not only to crystalline silicon cells, but also to back contact cells, perovskite stack cells, PERC, HIT and other solar cells, which can also be used as the battery body 1 in the solution provided in the embodiment of the present application.

[0073] like Figure 4 As shown, in a possible embodiment, the battery cell also includes a light-transmitting layer 3, which is located on the side of the substrate 11 facing the light-receiving surface. The light-transmitting layer 3 includes a second adhesive film layer 31 and light-converting particles 32. The light-converting particles 32 are arranged on the battery body 1 through the second adhesive film layer 31. The light-converting particles 32 are used to convert ultraviolet light into visible light. The light-converting particles 32 include at least one of a silicate containing a rare earth element and a sulfide containing a rare earth element. The rare earth elements include but are not limited to europium (Eu), dysprosium (Dy), etc. The light-converting particles 32 can be MgSiO3:Eu 2+ ,Dy 3+ , CdS quantum dots. Rare earth elements include but are not limited to europium (Eu), dysprosium (Dy), etc. The battery body 1 also includes a second passivation layer 13, which is located on the side of the substrate 11 facing the light receiving surface, and the light-transmitting layer 3 is located on the side of the second passivation layer 13 away from the substrate 11.

[0074] Crystalline silicon solar cells are affected by low ultraviolet brightness. During operation, the optical loss in the ultraviolet band is large, which will affect the short-circuit current and conversion efficiency of the battery body 1. At the same time, ultraviolet light will destroy the passivation structure of the battery body 1 located on the light-receiving surface, affecting the passivation reaction and causing the efficiency of the battery body 1 to decrease.

[0075] In the solution provided by the embodiment of the present application, by providing a light-transmitting layer 3 on the light-receiving surface of the battery body 1, the light-converting particles 32 can be used to convert ultraviolet light into visible light, thereby improving the utilization rate of ultraviolet light by the battery body 1, which is beneficial to improving the short-circuit current and efficiency of the battery body 1, and inhibiting ultraviolet attenuation. Since ultraviolet light can be converted into visible light by the light-converting particles 32 and then enter the battery body 1, the ultraviolet-induced attenuation of the battery body 1 can be reduced, which is beneficial to improving the service life of the battery body 1 and improving the efficiency of the battery body 1, which is more in line with actual use requirements.

[0076] The second adhesive film layer 31 may be a resin film layer, and the diameter of the light conversion particles 32 may be 20 nanometers to 500 nanometers. Figure 5 As shown, Figure 5 The SEM image of the cell with the light-transmitting layer provided in the embodiment of the present application. The diameter of the light-converting particles 32 can be 20 nanometers, 60 nanometers, 100 nanometers, 140 nanometers, 180 nanometers, 220 nanometers, 260 nanometers, 300 nanometers, 340 nanometers, 380 nanometers, 420 nanometers, 460 nanometers, 500 nanometers, etc.

[0077] When the diameter of the light-converting particle 32 is less than 20 nanometers, the diameter of the light-converting particle 32 is too small, making it difficult to prepare and affecting the uniformity of the light-converting particle 32. When the diameter of the light-converting particle 32 is greater than 500 nanometers, the diameter of the light-converting particle 32 is too large, making it difficult to set the light-transmitting layer 3, affecting the quality of the light-transmitting layer 3 and the production efficiency.

[0078] The second adhesive film layer 31 may be a resin film layer. When setting, light-converting particles 32 may be added to the resin material, and the mixed material of the resin material and the light-converting particles 32 may be set on the battery body 1 by spin coating, spray coating, scraping coating, etc.

[0079] The thickness of the second adhesive film layer 31 may be 5 nanometers to 100 nanometers, and the thickness of the second adhesive film layer 31 may be 5 nanometers, 10 nanometers, 20 nanometers, 30 nanometers, 40 nanometers, 50 nanometers, 60 nanometers, 70 nanometers, 80 nanometers, 90 nanometers, 100 nanometers, etc. When the thickness of the second adhesive film layer 31 is less than 5 nanometers, the thickness of the second adhesive film layer 31 is relatively thin, resulting in poor adhesion of the second adhesive film layer 31. When the thickness of the second adhesive film layer 31 is greater than 100 nanometers, the thickness of the second adhesive film layer 31 is too large, and the transmission distance of the light in the light-transmitting layer 3 increases, so the propagation loss will also increase, which will affect the overall efficiency.

[0080] The refractive index of the second adhesive film layer 31 is 1.3 to 1.7. The refractive index of the second adhesive film layer 31 may be 1.3, 1.4, 1.5, 1.6, 1.7, etc. The refractive index of the light conversion particle 32 is 1.1 to 1.6. The refractive index of the light conversion particle 32 may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, etc.

[0081] When the refractive index of the second adhesive film layer is too small and the refractive index of the light-converting particles 32 is too small, the overall refractive index of the light-transmitting layer 3 will be too small, and the light will not be completely absorbed when passing through the light-transmitting film, and part of the light will be reflected by the light-transmitting film, affecting the light absorption efficiency of the battery body 1. When the refractive index of the second adhesive film layer 31 is too large and the refractive index of the light-converting particles 32 is too large, the overall refractive index of the light-transmitting layer 3 will be too large, and the propagation speed of the light in the light-transmitting layer 3 will be slowed down, increasing the loss of light during the propagation process.

[0082] The excitation wavelength of the light conversion particle 32 is in the range of 200 nm to 500 nm, and / or the fluorescence characteristic peak is in the range of 400 nm to 900 nm.

[0083] The excitation wavelength of the light-transmitting layer 3 is 200 nanometers to 500 nanometers, and the excitation wavelength can include the wavelength range of ultraviolet light, so that the light-transmitting layer 3 can convert ultraviolet light into visible light, thereby improving the light absorption efficiency of the battery body 1 and reducing the damage of ultraviolet light to the passivation structure, which is beneficial to extending the service life of the battery cell and improving the conversion efficiency. The battery body 1 has a high absorption efficiency for visible light, but a low absorption efficiency for ultraviolet light. Therefore, the ultraviolet light is converted by the light-transmitting layer 3, and the characteristic peak of fluorescence is in the wavelength range of 400 nanometers to 900 nanometers, indicating that the light-transmitting layer 3 can emit visible and near-infrared light. Therefore, the light-transmitting layer 3 can convert ultraviolet light into visible light, thereby improving the overall absorption rate of the battery body 1 for light, and further improving the efficiency of the battery cell.

[0084] like Figure 6 As shown, Figure 6 The horizontal axis is the wavelength of the emitted light, and the vertical axis is the intensity of the fluorescence signal. The polished silicon wafer is a conventional battery structure, that is, a battery structure without a light-transmitting layer 3. The polished silicon wafer / light-converting particle 32 is a solution provided in the embodiment of the present application in which a light-transmitting layer 3 is provided on the battery body 1. Figure 6 The curves in the figure are the fluorescence signal intensities of different schemes under different excitation wavelengths. Figure 6 It can be seen that the fluorescence signal intensity of the embodiment with the light-transmitting layer 3 provided in the embodiment of the present application is significantly higher than that of the solution without the light-transmitting layer 3. Therefore, the solution provided in the embodiment of the present application can be beneficial to improving the overall efficiency by providing a light-transmitting layer 3 on the light-receiving surface of the battery body 1, which is more in line with actual usage requirements.

[0085] Taking TOPCon battery as an example, the data in Table 2 and Table 3 are obtained by testing the TOPCon battery:

[0086] Table 2

[0087] TOPCon Battery Voc(V) Isc(A) FF(%) Eta(%) Before coating the light-transmitting layer 0.7354 13.866 85.15 25.93 After coating the light-transmitting layer 0.7356 13.927 85.16 26.06

[0088] Table 3

[0089]

[0090] In the table, Voc is the open circuit voltage, Isc is the short circuit current, FF is the fill factor, and Eta is the efficiency. UV irradiation 15kWh means the total irradiation of the ultraviolet light to the battery cell is 15 kWh.

[0091] It can be seen from Tables 2 and 3 above that by providing a light-transmitting layer 3 on the light-receiving surface of the battery body 1 , the short-circuit current of the TOPCon battery can be increased by 61 mA and the conversion efficiency can be increased by 0.13%.

[0092] Based on the battery cells involved in the above embodiments, the embodiments of the present application also provide a photovoltaic module. The photovoltaic module may include battery cells. The battery cells may be the battery cells involved in any of the above embodiments. Since the battery cells have the above technical effects, the photovoltaic module provided by the embodiments of the present application also has corresponding technical effects, which will not be repeated here.

[0093] The photovoltaic module may include a cover plate, a first adhesive film, a battery string, a second adhesive film and a back plate in sequence along the thickness direction, and the battery string is composed of a plurality of battery cells connected in series and / or in parallel. The cover plate and the first adhesive film are located on the light-receiving side of the battery string, and the second adhesive film and the back plate may be arranged on the backlight side of the battery string.

[0094] In the scheme provided by the embodiment of the present application, the reflective layer 2 and the light-transmitting layer 3 can be coated after the battery body 1 is processed, which can reduce the influence on the grid line 14 of the battery body 1 and the influence on the passivation layer of the battery body 1. The light-transmitting layer 3 can be used to convert ultraviolet light into visible light, thereby increasing the absorption efficiency of the battery cell. At the same time, by converting ultraviolet light, the possibility of ultraviolet light damaging the passivation layer on the light-receiving side of the battery body 1 can be reduced, thereby helping to reduce the influence of ultraviolet light on the efficiency of the battery cell and helping to extend the service life of the battery cell. By providing a reflective layer on the backlight side of the battery body 1, the light passing through the battery body 1 can be reflected, so that the light not absorbed by the battery body 1 re-enters the battery body 1 so that the transmission distance of the light in the battery body 1 is close to twice the thickness of the battery body 1, thereby helping to improve the absorption of photons in the infrared band of the light by the battery body 1, thereby improving the utilization rate of light, reducing optical losses, and helping to improve the short-circuit current and conversion efficiency of the battery cell, which is more in line with actual use needs. At the same time, the reflective layer 2 and the light-transmitting layer 3 involved in the solution provided in the embodiment of the present application can be arranged on the battery body after the battery body 1 is processed. This method can reduce the influence of the reflective layer 2 and the light-transmitting layer 3 on the battery body 1. During production, the processing technology of the battery body 1 can be unchanged. After the conventional battery body 1 is processed, the coating process of the reflective layer 2 and the light-transmitting layer 3 can be added. Therefore, there is no need to adjust the original processing technology and processing equipment of the battery body 1, which is more convenient in the actual production process and more in line with actual use needs.

[0095] The embodiment of the present application provides a cell and a photovoltaic module, wherein the cell comprises a cell body 1 and a reflective layer 2, wherein the reflective layer 2 is located on one side of the cell body 1 along the thickness direction of the cell body 1. The cell body 1 comprises a light-receiving surface and a light-receiving surface, wherein the light-receiving surface and the light-receiving surface are located on opposite sides of the cell body 1 along the thickness direction of the cell body 1. Usually, along the gravity direction, the light-receiving surface is located above the light-receiving surface. The cell body comprises a substrate 11 and a first passivation layer 12, wherein the first passivation layer 12 is located on the side of the substrate 11 facing the light-receiving surface. The reflective layer 2 comprises a first adhesive film layer 21 and reflective particles 22, wherein the first adhesive film layer 21 is disposed on the side of the first passivation layer 12 away from the substrate 11, and the reflective particles 22 are disposed on the cell body 1 through the first adhesive film layer 21. By providing a reflective layer 2 on the backlight side of the battery body 1, the light passing through the battery body 1 can be reflected so that the light can be transmitted again in the battery body 1, which is beneficial to increase the total transmission distance of the light in the battery body 1, thereby improving the utilization rate of the light and reducing optical losses, thereby improving the overall efficiency of the battery cell and better meeting actual usage needs.

[0096] The above describes in detail the structure, features and effects of the present application based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present application, but the present application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of the present application, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present application.

Claims

1. A battery cell, characterized in that: The battery cell comprises: A battery body (1) comprising a substrate and a first passivation layer; A light reflecting layer (2), the light reflecting layer (2) being arranged on one side of the battery body (1) along the thickness direction of the battery body (1); The battery body (1) comprises a light-receiving surface and a backlight surface, and along the thickness direction of the battery body, the light-receiving surface and the backlight surface are located on opposite sides of the battery body (1); the first passivation layer is located on a side of the substrate close to the backlight surface; the reflective layer (2) comprises a first adhesive film layer (21) and reflective particles (22); the first adhesive film layer (21) is arranged on a side of the first passivation layer away from the substrate; and the reflective particles (22) are arranged on the battery body (1) through the first adhesive film layer (21).

2. The battery cell according to claim 1, characterized in that: The thickness of the first adhesive film layer (21) is 5 nanometers to 100 nanometers, and / or the refractive index of the first adhesive film layer (21) is 1.3 to 1.

7.

3. The battery cell according to claim 2, characterized in that: The first adhesive film layer (21) is a resin film layer.

4. The battery cell according to claim 1, characterized in that: The reflective particles (22) have a diameter of 50 nanometers to 800 nanometers, and / or a refractive index of 1.2 to 2.

5. The battery cell according to claim 1, characterized in that: The reflective particles (22) include at least one of chromium oxide, antimony oxide, titanium oxide, cobalt oxide, chromium nitride, antimony nitride, titanium nitride, cobalt nitride, chromium oxynitride, antimony oxynitride, titanium oxynitride, and cobalt oxynitride.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The first passivation layer comprises a first region and a second region, the first region is used for arranging the gate line, and the light reflecting layer (2) is arranged in the second region.

7. The battery cell according to claim 6, characterized in that: In the projection along the thickness direction of the battery cell, the total area of ​​the second region is a, the total area of ​​the reflective particles (22) is b, and the following condition is satisfied: 0.1a≤b≤a.

8. The battery cell according to any one of claims 1 to 5, characterized in that: Along the thickness direction of the battery cell, the thickness of the battery cell is 50 micrometers to 300 micrometers.

9. The battery cell according to any one of claims 1 to 5, characterized in that: The battery cell comprises a light-transmitting layer (3), the light-transmitting layer (3) being located on the side of the substrate (11) facing the light-receiving surface, the light-transmitting layer (3) comprising a second adhesive film layer (31) and light-converting particles (32), the light-converting particles (32) being arranged on the battery body (1) via the second adhesive film layer (31).

10. A photovoltaic module, characterized in that: The photovoltaic module comprises a cell, and the cell is the cell according to any one of claims 1 to 9.

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