CN113644155B - Backboard and photovoltaic module - Google Patents

Backboard and photovoltaic module Download PDF

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Publication number
CN113644155B
CN113644155B CN202110858213.8A CN202110858213A CN113644155B CN 113644155 B CN113644155 B CN 113644155B CN 202110858213 A CN202110858213 A CN 202110858213A CN 113644155 B CN113644155 B CN 113644155B
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China
Prior art keywords
reflecting structure
light
light reflecting
bearing surface
thickness
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CN202110858213.8A
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Chinese (zh)
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CN113644155A (en
Inventor
杨志强
宫欣欣
郭志球
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Zhejiang Jinko Solar Co Ltd
Jinko Solar Co Ltd
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Zhejiang Jinko Solar Co Ltd
Jinko Solar Co Ltd
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Priority to CN202110858213.8A priority Critical patent/CN113644155B/en
Publication of CN113644155A publication Critical patent/CN113644155A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • H01L31/049—Protective back sheets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/056—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means the light-reflecting means being of the back surface reflector [BSR] type
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Photovoltaic Devices (AREA)

Abstract

The embodiment of the invention provides a back plate and a photovoltaic module, wherein the back plate comprises: a back plate body having a bearing surface; the first light reflecting structure is positioned on the bearing surface, the top surface of the first light reflecting structure, which is far away from the bearing surface, is a reflecting surface, and the reflecting surface is used for enabling light rays incident on the reflecting surface to be diffusely reflected in a direction far away from the bearing surface; the second light reflecting structure is located the loading face, and the second light reflecting structure is located at least one side of first light reflecting structure width direction, and the second light reflecting structure includes protruding structure, and protruding structure is first side for the side of first light reflecting structure dorsad, and first side is plane or arcwall face, and first side face is towards being close to the direction slope of first light reflecting structure. The embodiment of the invention is beneficial to improving the probability of reflecting the light incident on the backboard to the battery piece by the backboard so as to improve the utilization rate of the battery piece to the light.

Description

Backboard and photovoltaic module
Technical Field
The embodiment of the invention relates to the technical field of solar cells, in particular to a back plate and a photovoltaic module.
Background
With the remarkable problems of energy shortage, global temperature rise, and environmental deterioration, solar energy is receiving increasing attention as a green renewable energy source. A photovoltaic module is a device that converts renewable solar energy into electrical energy.
The power generation power of the battery piece in the photovoltaic module is an important index for measuring the performance of the photovoltaic module, and the utilization efficiency of the photovoltaic module to the light energy is directly reflected. Specifically, the high power generation is beneficial to reducing the cost in the manufacturing process of the photovoltaic module, and under the condition that the power generation power of the photovoltaic module is the same, the size of the photovoltaic module is smaller as the power generation power of the battery piece is higher, and the weight of the corresponding photovoltaic module is also lower.
However, the probability that the back plate reflects the light incident on the back plate to the battery piece in the photovoltaic module is low at present, so that the utilization rate of the battery piece to the light in the photovoltaic module is influenced, and the generated power of the battery piece is influenced.
Disclosure of Invention
The technical problem solved by the embodiment of the invention is to provide the backboard and the photovoltaic module, which are beneficial to reflecting the light incident on the backboard to the battery piece by the backboard so as to ensure the utilization rate of the light and the power generation of the photovoltaic module.
To solve the above problems, an embodiment of the present invention provides a back plate, including: the backboard body is provided with a bearing surface; the first light reflecting structure is positioned on the bearing surface, the top surface of the first light reflecting structure, which is far away from the bearing surface, is a reflecting surface, and the reflecting surface is used for enabling light rays incident on the reflecting surface to be diffusely reflected; the second light reflecting structure is located on the bearing surface, the second light reflecting structure is located on at least one side of the width direction of the first light reflecting structure, the second light reflecting structure comprises a protruding structure, the side surface, opposite to the first light reflecting structure, of the protruding structure is a first side surface, the first side surface is a plane or an arc-shaped surface, and the first side surface is inclined towards the direction close to the first light reflecting structure.
In addition, the first side face is a plane, and an included angle between the first side face and the bearing surface is 30-45 degrees; or the first side surface is an arc surface and is recessed towards the direction close to the first light reflecting structure.
In addition, the first side surface is provided with a sawtooth structure.
In addition, the number of the protruding structures is at least two, in the direction pointing to the second light reflecting structure along the first light reflecting structure, the protruding structures are sequentially arranged, and the thicknesses of the adjacent protruding structures in the direction perpendicular to the bearing surface are sequentially reduced.
In addition, the included angle between the side surfaces of the two sides of the reflecting surface in the width direction and the bearing surface is smaller than or equal to 90 degrees.
In addition, the reflecting surface is parallel to the bearing surface, and the side surfaces on two sides of the reflecting surface in the width direction are perpendicular to the bearing surface.
In addition, in the direction perpendicular to the bearing surface, the thickness of the first light reflecting structure is not smaller than that of the second light reflecting structure.
In addition, in the direction that the second light reflecting structure points to the first light reflecting structure, the ratio of the bottom width of the first light reflecting structure to the bottom width of the second light reflecting structure is 0.8-1.2.
In addition, the back plate further includes: the pyramid structure is located the bearing surface, just the pyramid structure is located the second reflection of light structure is opposite to the one side of first reflection of light structure, the pyramid structure is used for making incident to the light of pyramid structure take place the reflection in order to form third reflection light, third reflection light orientation keep away from the pyramid structure and keep away from the direction propagation of bearing surface.
In addition, the degree of the acute angle formed between the side surface of the pyramid structure and the bearing surface is 15-45 degrees.
In addition, the backboard body comprises a fluorine film and a PET film which are arranged in a laminated mode, and the first reflecting structure and the second reflecting structure are both printed and coated on the bearing surface of one side, opposite to the fluorine film, of the PET film.
In addition, the materials of the first reflecting structure and the second reflecting structure are a mixture composed of tetrafluoroethylene, titanium white powder, epoxy resin, light stabilizer and silane coupling agent, or a mixture composed of polyvinylidene fluoride, titanium white powder, epoxy resin, light stabilizer and silane coupling agent
In addition, the reflectivity of the first reflecting structure and the reflectivity of the second reflecting structure are both larger than the reflectivity of the backboard body.
In addition, the surface roughness Ra of the reflecting surface is 50 or more.
Correspondingly, the embodiment of the invention also provides a photovoltaic module, which comprises: a back sheet as in any of the above; the battery plate is provided with a light-facing surface and a backlight surface which are opposite, a gap is arranged between every two adjacent battery plates, and the first light-reflecting structure is arranged in the gap and has the same extending direction as the extending direction of the gap.
In addition, the orthographic projection of the first reflecting structure on the bearing surface is positioned in the orthographic projection of the gap on the bearing surface, and the orthographic projection of the second reflecting structure on the bearing surface is at least partially overlapped with the orthographic projection of the gap on the bearing surface.
In addition, a gap is formed between the backlight surface and the bearing surface, and in the direction perpendicular to the bearing surface, the thickness of the first reflecting structure and the thickness of the second reflecting structure are not larger than the thickness of the gap. .
In addition, the thickness of the first reflecting structure is 5 um-20 um, and the thickness of the second reflecting structure is not more than the thickness of the first reflecting structure.
In addition, a space is arranged between the backlight surface and the bearing surface, and the thickness of the first reflecting structure and the thickness of the second reflecting structure are respectively 2-3 times of the thickness of the space in the direction perpendicular to the bearing surface.
In addition, the thickness of the first reflecting structure is equal to that of the second reflecting structure, and the thickness is respectively 200 um-3000 um.
In addition, a plurality of battery pieces are sequentially connected in series along the first direction to form a battery string, at least two battery strings are sequentially arranged along a second direction intersecting the first direction, a first gap is formed between every two adjacent battery strings, the first gap extends along the first direction, and the extending direction of the first reflecting structure, the extending direction of the second reflecting structure and the extending direction of the first gap are consistent.
In addition, at least two battery strings are sequentially arranged along the first direction, a second gap is formed between the battery pieces of the adjacent battery strings, the second gap extends along the second direction, and the first light reflecting structure and the second light reflecting structure also extend along the second direction.
Compared with the related art, the technical scheme provided by the embodiment of the invention has the following advantages:
In the above technical scheme, set up first reflection of light structure and second reflection of light structure on the loading surface of backplate body, first reflection of light structure's reflection surface is used for making incident to the light of reflection surface take place diffuse reflection in order to form first reflection of light, second reflection of light structure includes protruding structure, protruding structure is first side for the side of first reflection of light structure dorsad, first side is plane or arcwall face, and first side face is towards the direction slope that is close to first reflection of light structure, consequently, the contained angle of orientation first reflection of light structure between tangent plane and the loading surface of any point on the first side is the acute angle for incident to the light of first side takes place the reflection in order to form second reflection of light, and second reflection of light direction propagation of keeping away from first reflection of light structure.
When the back plate is applied to a photovoltaic module with at least two adjacent cells with gaps, the first light reflecting structure and the second light reflecting structure can act together, so that more light incident into the gaps of the adjacent cells is reflected to the cells through the first light reflecting structure and the second light reflecting structure, and the probability that the back plate reflects the light incident to the back plate to the cells is improved; on the other hand, compared with the flat and smooth backboard body, the first light reflecting structure and the second light reflecting structure with certain thicknesses are beneficial to reducing the length of the propagation path of light rays incident into the gaps of adjacent battery pieces and reflected onto the battery pieces, so that the light intensity of the light rays received by the battery pieces is improved, and the light intensity of the battery pieces and the light utilization rate of the battery pieces are improved, so that the power generation of the battery pieces is improved.
In addition, the reflectivity of the first reflecting structure and the reflectivity of the second reflecting structure are both larger than the reflectivity of the backboard body, so that the first reflecting structure and the second reflecting structure are favorable for guaranteeing high reflectivity for light rays entering gaps of adjacent battery pieces, the probability that the light rays entering the gaps of the adjacent battery pieces are reflected to the battery pieces through the first reflecting structure and the second reflecting structure is further improved, and therefore the utilization rate of the light rays of the battery pieces is further improved, and the power generation of the battery pieces is further improved.
Drawings
One or more embodiments are illustrated by way of example in the accompanying drawings, which are not intended to be limiting in scale unless specifically stated otherwise.
Fig. 1 is a schematic top view of a back plate and a battery plate according to an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view of FIG. 1 along the Y direction;
fig. 3 to 11 are schematic views of 9 partial cross-sectional structures corresponding to a back plate and a battery plate according to an embodiment of the invention;
Fig. 12 to 14 are schematic views of 3 partial cross-sectional structures of a photovoltaic module according to another embodiment of the present invention;
fig. 15 and 16 are schematic top view structures of 2 kinds of battery strings according to another embodiment of the present invention.
Detailed Description
As known from the background art, the probability of reflecting the light incident on the back plate to the battery plate needs to be improved, and the utilization rate of the light by the battery plate and the power generation of the battery plate need to be improved.
The analysis shows that the glaze layer on the surface of the conventional grid back plate is a flat and smooth coating, light rays entering gaps between adjacent cells are mainly reflected to a glass cover plate above the cells through the grid back plate, then the light rays are reflected to the light-facing surface of the cells through the glass cover plate, and the light rays reflected to the back surface of the cells through the grid back plate are few and have low probability. In addition, in the conventional grid back plate, an inner layer bonding layer is further arranged between the back plate body and the grid layer, so that the grid back plate is more in component materials and higher in preparation cost.
In order to solve the above-mentioned problems, an embodiment of the present invention provides a back plate, in which a first reflective structure and a second reflective structure are disposed on a bearing surface of a back plate body, where a reflective surface of the first reflective structure is configured to diffuse light incident on the reflective surface to form a first reflected light, the second reflective structure includes a protrusion structure, a side surface of the protrusion structure opposite to the first reflective structure is a first side surface, the first side surface is a plane or an arc surface, and the first side surface is inclined toward a direction close to the first reflective structure, so that an included angle between a tangential surface of any point on the first side surface and the bearing surface toward the first reflective structure is an acute angle, and then the second reflective structure may be configured to reflect light incident on the first side surface to form a second reflected light, where the second reflected light propagates toward a direction away from the first reflective structure. When the back plate is applied to a photovoltaic module with at least two adjacent cells with gaps, the first light reflecting structure and the second light reflecting structure can act together, so that more light incident into the gaps of the adjacent cells is reflected to the cells through the first light reflecting structure and the second light reflecting structure, and the probability that the back plate reflects the light incident to the back plate to the cells is improved; on the other hand, compared with the flat and smooth backboard body, the first light reflecting structure and the second light reflecting structure with certain thicknesses are beneficial to reducing the length of the propagation path of light rays incident into the gaps of adjacent battery pieces and reflected onto the battery pieces, so that the light intensity of the light rays received by the battery pieces is improved, and the light intensity of the battery pieces and the light utilization rate of the battery pieces are improved, so that the power generation of the battery pieces is improved.
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. The claimed application may be practiced without these specific details and with various changes and modifications based on the following embodiments.
An embodiment of the present invention provides a back plate, and the back plate provided by the embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Fig. 1 to 11 are schematic structural diagrams corresponding to a back plate and a battery piece according to an embodiment of the invention.
Referring to fig. 1 and 2 in combination, the back plate 100 includes: the backboard body 110, the backboard body 110 has a bearing surface c; the first light reflecting structure 120 is located on the bearing surface c, the top surface of the first light reflecting structure 120 away from the bearing surface c is a reflecting surface f, and the reflecting surface f is used for enabling light rays incident on the reflecting surface f to be diffusely reflected; the second light reflecting structure 130 is located on the carrying surface c, the second light reflecting structure 130 is located on at least one side of the width direction Y of the first light reflecting structure 120, the second light reflecting structure 130 includes a protrusion structure 140, a side surface of the protrusion structure 140 opposite to the first light reflecting structure 120 is a first side surface d, the first side surface d is a plane or an arc surface, and the first side surface d is inclined towards a direction approaching to the first light reflecting structure 120.
The first reflective structure 120 has an extending direction X and a width direction Y perpendicular to the extending direction X, and the first side d of the second reflective structure 130 is inclined toward a direction approaching the first reflective structure 120, so that an included angle between a tangential plane of any point on the first side d and the bearing surface c toward the first reflective structure 120 is an acute angle, and when the light incident on the first side d is reflected to form a second reflected light, the second reflected light is beneficial to propagating toward a direction far away from the first reflective structure 120.
In some embodiments, the back sheet 100 may be applied to a photovoltaic module having at least two adjacent battery pieces 101 with a gap I, the battery pieces 101 having opposite light-facing surfaces a and backlight surfaces b, and the bearing surface c being a surface of the back sheet body 110 facing the battery pieces 101; the extending direction X of the first light reflecting structure 120 is consistent with the extending direction of the gap I, and the orthographic projection of the first light reflecting structure 120 on the bearing surface c is located in the orthographic projection of the gap I on the bearing surface c, so as to make the first reflected light propagate to the light-facing surface a; the second reflecting structure 130 is configured to transmit the second reflected light to the light-facing surface a or the light-facing surface b.
In fig. 1 and 2, two adjacent battery pieces 101 having a gap I are taken as an example, and in practical applications, a plurality of battery pieces 101 spaced from each other may be arranged in sequence along the width direction Y.
In some embodiments, the second light reflecting structure 130 is located on two sides of the width direction Y of the first light reflecting structure 120 on the bearing surface c opposite to the gap I of the adjacent battery piece 101, and the width direction Y is the direction in which the first light reflecting structure 120 points to the second light reflecting structure 130, and the extending direction X is the direction intersecting the width direction Y, and in one example, the extending direction X is perpendicular to the width direction Y.
Further, for the battery piece 101 located in the edge area, that is, one side of the battery piece 101 along the width direction Y is not adjacent to another battery piece 101, the second light reflecting structure 130 may be located on only one side of the first light reflecting structure 120 along the width direction Y, and the second light reflecting structure 130 is located on one side of the first light reflecting structure 120 close to the battery piece 101, which is beneficial to fully reflecting the light not directly irradiated on the battery piece 101 to the battery piece 101 through the first light reflecting structure 120 and the second light reflecting structure 130, so as to improve the probability that the light not directly irradiated on the battery piece 101 is reflected to the battery piece 101, thereby improving the utilization ratio of the light by the battery piece 101.
In other embodiments, for a single battery cell, the second light reflecting structure may be located around the orthographic projection of the battery cell on the carrying surface, and the first light reflecting structure is located around the second light reflecting structure, so as to improve the probability that the light not directly irradiated on the battery cell is reflected to the battery cell.
The first light reflecting structure and the second light reflecting structure will be specifically described below with reference to fig. 1 to 11. Specifically, the reflectivity of the first light reflecting structure 120 and the reflectivity of the second light reflecting structure 130 are both greater than the reflectivity of the back plate body 110. Therefore, compared with the use of the flat and smooth back plate body 110 to reflect the light onto the battery piece 101, the probability of reflecting the light incident to the first light reflecting structure 120 and the second light reflecting structure 130 is increased, so that more light is reflected onto the battery piece 101, thereby further improving the utilization rate of the light by the battery piece 101 and further improving the power generation of the battery piece 101. Wherein, the reflectivity of the first light reflecting structure 120 and the reflectivity of the second light reflecting structure 130 may be selected to be 70% -90%.
In some embodiments, the back plate may further comprise: and a reflective film (not shown) disposed on the surfaces of the first and second light reflecting structures 120 and 130 for further increasing the reflectivity of the surfaces of the first and second light reflecting structures 120 and 130 so as to further increase the probability of light incident on the first and second light reflecting structures 120 and 130 being reflected to the battery cell 101. Wherein the material of the reflective film comprises at least one of polyvinyl chloride (PVC, polyvinyl chloride), cast polypropylene or terpolymer (ABS, acrylonitrile butadiene Styrene copolymers) composed of butadiene-acrylonitrile-styrene. Specifically, the material of the reflecting film can be polyvinyl chloride, so that the reflecting film has the characteristics of high strength, strong weather resistance, long service life and strong stability.
In some embodiments, both the first light reflecting structure 120 and the second light reflecting structure 130 are in direct contact with the bearing surface c. In some examples, the back plate body 110 includes a fluorine film and a PET (polyethylene terephthalate ) film that are stacked, and the first light reflecting structure 120 and the second light reflecting structure 130 are both printed on the bearing surface c of the PET film on the side opposite to the fluorine film. The PET film may be a material that is subjected to corona treatment in advance, where the corona treatment is favorable to improving the surface free energy of the bearing surface c, so that the bearing surface c is changed from a nonpolar surface to a polar surface, so as to improve the adhesion fastness between the back plate body 110 and the first and second light reflecting structures 120 and 130, and to reduce the constituent materials of the back plate 100 and reduce the manufacturing cost of the back plate 100 compared with a mode of providing an inner layer bonding layer between the back plate body and the grid layer.
In some embodiments, in the direction that the second light reflecting structure 130 points to the first light reflecting structure 120, the ratio of the bottom width of the first light reflecting structure 120 to the bottom width of the second light reflecting structure 130 is 0.8-1.2, on the one hand, the bottom width of the first light reflecting structure 120 is substantially consistent with the bottom width of the second light reflecting structure 130, which is favorable for improving the probability that most of the light incident on the first light reflecting structure 120 can be reflected to the light-guiding surface a of the battery piece 101 through the first light reflecting structure 120 by adjusting the propagation path of the light incident on the gap I between adjacent battery pieces 101, and the probability that most of the light incident on the first light reflecting structure 120 can be reflected to the light-guiding surface a of the battery piece 101 through the second light reflecting structure 130 is improved, and the probability that most of the light incident on the second light reflecting structure 130 can be reflected to the backlight surface b or the light-guiding surface a of the battery piece 101 through the second light reflecting structure 130; on the other hand, the bottom width of the first light reflecting structure 120 and the bottom width of the second light reflecting structure 130 are set to be the same, which is favorable for reducing the proofing difficulty of the printing templates for preparing the first light reflecting structure 120 and the second light reflecting structure 130, reducing the technological difficulty of screen printing, and also is favorable for monitoring the bottom width of the first light reflecting structure 120 and the bottom width of the second light reflecting structure 130 in production.
Further, in the direction Z perpendicular to the bearing surface c, the thickness of the first light reflecting structure 120 may be not less than the thickness of the second light reflecting structure 130. Specifically, referring to fig. 3, the thickness of the first light reflecting structure 120 is greater than the thickness of the second light reflecting structure 130, wherein the thickness of the first light reflecting structure 120 is: in the direction Z perpendicular to the bearing surface c, the first light reflecting structure 120 has a vertical distance between the top end, which is farthest from the bearing surface c, and the bearing surface c; the thickness of the second light reflecting structure 130 is: in the direction Z, the second light reflecting structure 130 is perpendicular to the bearing surface c at a perpendicular distance between the top end furthest from the bearing surface c. In this way, the greater the thickness of the first light reflecting structure 120, the shorter the propagation distance required for reflecting the light incident on the first light reflecting structure 120 to the light-facing surface a of the battery piece 101, the greater the light intensity when the light is absorbed by the light-facing surface a of the battery piece 101, thereby improving the power generation of the battery piece 101.
The light intensity of the light refers to the luminous intensity (Luminous intensity) of the light, and in photometry, simply referred to as light intensity or luminosity, is used to represent the physical quantity of luminous flux in a unit solid angle in a given direction of the light source.
In some embodiments, the first light reflecting structure 120 and the second light reflecting structure 130 may be integrally formed, so that the material of the first light reflecting structure 120 and the material of the second light reflecting structure 130 are the same, which is beneficial to reducing the manufacturing process steps of the back plate 100 and reducing the manufacturing cost and complexity of the back plate 100. The material of the first light reflecting structure 120 and the material of the second light reflecting structure 130 may be a mixture of tetrafluoroethylene, titanium white, epoxy resin, light stabilizer and silane coupling agent or a mixture of polyvinylidene fluoride, titanium white, epoxy resin, light stabilizer and silane coupling agent. The first light reflecting structure 120 and the second light reflecting structure 130 which adopt the materials have strong absorption capability to ultraviolet light, so that when the first light reflecting structure 120 and the second light reflecting structure 130 jointly cover the surface of the backboard body 110, the ultraviolet light is prevented from entering the backboard body 110 to damage the backboard body 110, and the service life of the backboard body 110 is prolonged, so that the service life of the backboard 100 is prolonged.
Referring to fig. 2 to 10, the first side d is inclined toward a direction approaching the first light reflecting structure 120. In some embodiments, when the first side d is planar and the acute angle formed between the first side d and the bearing surface c ranges from 30 ° to 75 °, it is beneficial to ensure that a substantial portion of the light incident on the first side d can be reflected onto the battery piece 101.
In some embodiments, referring to fig. 8, the first side d is a plane, and an acute angle formed between the first side d and the bearing surface c ranges from 30 ° to 45 °, when the inclination degree of the first side d is within the range, it is beneficial to improve the probability that the first reflection light beam incident on the first side d propagates to the backlight surface b, that is, when the angle range is within the range, most of the second reflection light beam incident on the backlight surface b can propagate to the backlight surface b without secondary reflection by the bearing surface c, and can be directly reflected by the first side d to reach the backlight surface b, so that the light intensity reaching the backlight surface b is reduced due to the fact that the light beam is absorbed by the bearing surface c when the light beam is reflected by the bearing surface c secondarily, thereby being beneficial to improving the intensity of the light beam absorbed by the backlight surface b of the battery piece 101 and being beneficial to improving the power generation of the battery piece 101.
In other embodiments, referring to fig. 7, the first side d is an arc surface and is recessed toward a direction approaching the first light reflecting structure 120. Therefore, the width of the protruding structure 140 away from the top end of the bearing surface c is smaller than that of the bottom end of the protruding structure 140 contacting the bearing surface c, the first side d is favorable for converging the light incident to the first side d, and the second reflected light incident to the first side d can be reflected to the battery piece 101 at a better reflection angle, and most of the second reflected light incident to the backlight surface b is directly reflected to the first side d without secondary reflection by the bearing surface c, so that the light intensity reaching the backlight surface b is reduced due to the fact that the light is absorbed by the bearing surface c when the light is secondarily reflected by the bearing surface c, the total amount and the intensity of the light reflected to the backlight surface b of the battery piece 101 are improved, the light intensity absorbed by the backlight surface b of the battery piece 101 is increased, the utilization rate of the light by the battery piece 101 is improved, and the power generation of the battery piece 101 is improved.
In some embodiments, referring to fig. 5, the surface of the first side is provided with an uneven saw tooth structure, and the saw tooth structure can reflect the light incident to the first side d from a plurality of different directions onto the battery piece 101, so as to improve the probability of reflecting the light with the incident point located in the area where the second light reflection structure 130 is located onto the battery piece 101, and further increase the total amount of light absorbed by the battery piece 101, so as to improve the utilization rate of the light by the battery piece 101 and improve the power generation of the battery piece 101.
In other embodiments, referring to fig. 6 and 7, when the first side d is an inclined plane or a concave plane, the protrusion structure 140 has a second side e opposite to the first side d, the second side e faces the first reflecting structure 120, and the second side e is perpendicular to the carrying surface c, and compared with the second side e, more light incident on the area where the second reflecting structure 130 is located will be incident on the first side d, i.e. more light incident on the area where the second reflecting structure 130 is located will be reflected to the battery piece 101 through the first side d, so that the probability of reflecting the light incident on the second reflecting structure 130 to the battery piece 101 is advantageously improved, so as to improve the utilization ratio of the light by the battery piece 101.
In the above embodiment, the number of the bump structures 140 is taken as 2 as an example in fig. 2 to 7, and in practical application, the number of the bump structures 140 may be 1, or may be 3 or more, and the above embodiment does not limit the number of the bump structures 140.
In still other embodiments, referring to fig. 8, the second light reflecting structure 130 includes at least two protrusion structures 140, each protrusion structure 140 is sequentially arranged in a direction along the first light reflecting structure 120 toward the second light reflecting structure 130, and the thickness of adjacent protrusion structures 140 in a direction perpendicular to the bearing surface c is sequentially reduced. As shown in fig. 8, the design can avoid that the light incident on the first side surface d of the protruding structure 140 close to the first light reflecting structure 120 is blocked by the second side wall e (refer to fig. 7) of the adjacent protruding structure 140 far from the first light reflecting structure 120 and is far from the battery piece 101 in the propagation path of reflecting to the battery piece 101, so that the probability that the light with the incident point in the area where the second light reflecting structure 130 is located is reflected to the battery piece 101 can be improved, and the utilization rate of the light by the battery piece 101 can be increased.
In some embodiments, the roughness Ra of the reflective surface f of the first reflective structure 120 is greater than or equal to 50, so that the reflective surface f has a significantly visible concave-convex shape relative to a smooth plane with lower surface roughness, when light is incident on the reflective surface f of the first reflective structure 120, the light can be diffusely reflected to the light-directing surface a of the battery piece 101 due to the rough surface structure of the reflective surface f, so as to increase the probability of reflecting the light to the light-directing surface a of the battery piece 101, thereby increasing the total amount of light absorbed by the battery piece 101 to the light-directing surface a, so as to increase the utilization rate of the light by the battery piece 101 and increase the power generation of the battery piece 101, and meanwhile, the surface roughness Ra of the first reflective structure 120 is greater than or equal to 50, which is beneficial to reducing the printing difficulty of the first reflective structure 120.
In some embodiments, the included angle between the lateral sides of the reflective surface f of the first reflective structure 120 and the bearing surface c is less than or equal to 90 °. For example, the cross-sectional shape of the first light reflecting structure 120 may be trapezoidal. After the arrangement is adopted, the width of the part of the first reflecting structure 120 close to the bearing surface c is larger, so that the part is conveniently and accurately positioned to a preset position on the bearing surface c during laying, meanwhile, the attaching area of the first reflecting structure 120 and the bearing surface c is large, and the mounting stability of the first reflecting structure 120 on the bearing surface c can be enhanced; and compared with the structure with wide upper part and narrow lower part, the light reflecting structure is easier to form, and is convenient to be integrally manufactured with the second light reflecting structure 130 and arranged on the bearing surface c.
In some embodiments, the reflecting surface f of the first reflecting structure is parallel to the bearing surface c, so that the probability that the light incident on each point on the reflecting surface f is reflected to the light-facing surface a of the battery piece 101 is equal, so that the probability that the first reflecting structure 120 reflects the light to the light-facing surface a of the battery piece 101 is improved as a whole, the total amount of the light absorbed by the light-facing surface a of the battery piece 101 is increased, the utilization rate of the light by the battery piece 101 is improved, and the power generation of the battery piece 101 is improved.
Further, referring to fig. 9, the lateral sides of the reflective surface f of the first reflective structure 120 in the width direction are perpendicular to the bearing surface c, and the first lateral side d and the second lateral side e of the second reflective structure 130 are inclined surfaces. Thus, the lateral sides of the reflective surface f in the width direction are perpendicular to the bearing surface c, and the reflective surface f is parallel to the bearing surface c, i.e. in a plane perpendicular to the bearing surface c, the cross-sectional shape of the first light reflecting structure 120 is rectangular. Compared with the first reflective structure 120 having an included angle between the side surface and the carrying surface c smaller than 90 ° (e.g., the trapezoid cross-section of the first reflective structure 120), the area of the reflective surface f of the first reflective structure 120 away from the carrying surface c is larger, so that more light is incident to the reflective surface f, and further the light incident to the area where the first reflective structure 120 is located can be reflected to the light-directing surface a of the battery piece 101, which increases the total amount of light absorbed by the light-directing surface a, and increases the utilization rate of the light by the light-directing surface a and the power generation of the battery piece 101.
Of course, in other embodiments, the included angle between the side surface of the first reflective structure and the supporting surface may be an acute angle, and the area of the reflective surface f is smaller, which is not limited herein.
It should be noted that, fig. 2 is taken as an example in which both the top end of the second light reflecting structure 130 away from the bearing surface c and the top surface of the first light reflecting structure 120 away from the bearing surface c are lower than the backlight surface b, fig. 3 is taken as an example in which the top end of the second light reflecting structure 130 away from the bearing surface c is lower than the backlight surface b and the top surface of the first light reflecting structure 120 away from the bearing surface c is higher than the backlight surface b, and fig. 10 is taken as an example in which both the top end of the second light reflecting structure 130 away from the bearing surface c and the top surface of the first light reflecting structure 120 away from the bearing surface c is higher than the backlight surface b. In practical applications, the above description is applicable to not only the case that the top end of the second light reflecting structure far away from the bearing surface is lower than the backlight surface and/or the top surface of the first light reflecting structure far away from the bearing surface is higher than the backlight surface, but also the case that the top end of the second light reflecting structure far away from the bearing surface is not lower than the backlight surface and/or the top surface of the first light reflecting structure far away from the bearing surface is not higher than the backlight surface.
The thicknesses of the first light reflecting structure and the second light reflecting structure in the direction perpendicular to the bearing surface are described in detail below in two specific embodiments.
In some embodiments, the thickness of the second light reflecting structure 130 is not greater than that of the first light reflecting structure 120, and the thickness of the first light reflecting structure 120 may be 5um to 20um in the direction Z perpendicular to the bearing surface c. Specifically, as the thickness of the first light reflecting structure 120 increases, the shorter the propagation distance required for reflecting the light incident on the first light reflecting structure 120 to the light-facing surface a of the battery piece 101, the higher the reflectivity of the first light reflecting structure 120 increases, and the greater the light intensity of the light absorbed by the light-facing surface a of the battery piece 101, thereby increasing the power generation of the battery piece 101. When the thickness of the first light reflecting structure 120 is 20um, the reflectivity of the first light reflecting structure 120 may reach 90%.
In other embodiments, referring to fig. 10, the thickness of the first light reflecting structure 120 is 100um to 3000um and the thickness of the second light reflecting structure 130 is 100um to 3000um in the direction perpendicular to the bearing surface c.
When the top end of the second reflective structure 130, which is far from the bearing surface c, is higher than the light-directing surface a, and the acute angle between the first side surface d of the protruding structure 140 and the bearing surface c is smaller, when the reflective point of the second reflective light is located at the top end portion of the second reflective structure 130, which is far from the bearing surface c, the second reflective light is reflected to the light-directing surface a of the battery piece 101 by the second reflective structure 130, and when the reflective point of the second reflective light is located at the bottom end portion of the second reflective structure 130, which is close to the bearing surface c, the second reflective light is reflected to the backlight surface b of the battery piece 101 by the second reflective structure 130. Therefore, the light incident on the second light reflecting structure 130 may be reflected to the backlight surface b and the light-facing surface a, which is beneficial to increasing the total amount of light absorbed by the battery piece 101, thereby increasing the power generated by the battery piece 101.
It should be noted that, in fig. 10, the thickness of the first light reflecting structure 120 is equal to the thickness of the second light reflecting structure 130, and in practical application, the thickness of the first light reflecting structure may be unequal to the thickness of the second light reflecting structure according to different application scenarios.
It should be noted that, in fig. 2 to fig. 10, the orthographic projection of the second light reflecting structure 130 on the bearing surface c is located in the orthographic projection of the gap I on the bearing surface c, and the combined orthographic projection of the first light reflecting structure 120 and the second light reflecting structure 130 on the bearing surface c coincides with the orthographic projection of the gap I on the bearing surface c as an example, and in practical application, the second light reflecting structure 130 may also be located directly under the battery piece 101.
In other embodiments, referring to fig. 11, the back plate 100 may further include: the pyramid structure 150, the pyramid structure 150 is located on the bearing surface c, and the pyramid structure 150 is located on a side of the second light reflecting structure 130 away from the first light reflecting structure 120, and the pyramid structure 150 is configured to reflect the light incident on the pyramid structure 150 to form a third reflected light, where the third reflected light propagates in a direction away from the pyramid structure 150 and away from the bearing surface c.
In some embodiments, when the backsheet 100 is applied in a photovoltaic module, the front projection of the pyramid structure 150 on the carrying surface c is located in the front projection of the cell 101 on the carrying surface c for reflecting light incident on the pyramid structure 150 to the backlight surface b. Specifically, the degree of the acute angle formed between the side surface of the pyramid structure 150 and the bearing surface c is smaller than the degree of the acute angle formed between the first side surface b of the second light reflecting structure 130 and the bearing surface c, which is beneficial to improving the probability of reflecting the light directly under the backlight surface b to the backlight surface b, so as to further improve the utilization ratio of the light by the backlight surface b. In one example, the acute angle formed between the sides of the pyramid structure 150 and the bearing surface c is 15 to 45 degrees.
The pyramid structure 150 may be a triangular pyramid structure, a rectangular pyramid structure, or a pentagonal pyramid structure, and the number of side edges of the pyramid structure 150 is not limited in this embodiment.
Specifically, the first light reflecting structure 120, the second light reflecting structure 130 and the pyramid structure 150 may be integrally formed, so that the material of the first light reflecting structure 120, the material of the second light reflecting structure 130 and the material of the pyramid structure 150 are the same, which is beneficial to further reducing the manufacturing process steps of the back plate 100 and further reducing the manufacturing cost and complexity of the back plate 100. Wherein, the method of forming the first light reflecting structure 120, the second light reflecting structure 130 and the pyramid structures 150 includes screen printing or roll printing.
Further, the reflective film may be further located on the surface of the pyramid structure 150, so as to increase the reflectivity of the surface of the pyramid structure 150, so as to further increase the probability of the light incident on the pyramid structure 150 being reflected to the backlight b of the cell 101.
It should be noted that, in fig. 2 to 11, taking the same degree of the acute angle between the first side surface d and the bearing surface c of the plurality of protruding structures 140 as an example, in practical application, the degree of the acute angle between the first side surface d and the bearing surface c of the adjacent protruding structures 140 may also be different, and further, in the direction in which the first light reflecting structure 120 points to the second light reflecting structure 130, the degree of the acute angle formed between the first side surface b and the bearing surface c of the adjacent protruding structures 140 may be sequentially reduced. In addition, fig. 2 to 11 illustrate that there is no gap between the bottoms of the adjacent bump structures 140, and in practical applications, there may be a gap between the bottoms of the adjacent bump structures 140, and the above embodiment does not limit the size of the gap between the bottoms of the adjacent bump structures 140.
In addition, in the above embodiment, taking the elongated structure in which the protrusion structures 140 in the second light reflecting structure 130 in fig. 1 extend along the extending direction X as an example, in practical application, there may also be a plurality of protrusion structures 140 in the second light reflecting structure 130 in the extending direction X, and the protrusion structures may be sequentially arranged along the extending direction X, that is, the plurality of protrusion structures 140 in the second light reflecting structure 130 may be sequentially arranged along the width direction Y and/or the plurality of protrusion structures 140 may be sequentially arranged along the extending direction X.
It should be noted that, in fig. 1, the second light reflecting structures 130 are illustrated as being located at two sides of the battery piece 101 along the extending direction X, the first light reflecting structures 120 are also located at two sides of the battery piece 101 along the extending direction X, and are located between two second light reflecting structures 130, in practical application, for a single battery piece 101, the second light reflecting structures 130 may be disposed at each side of the battery piece 101, and the first light reflecting structures 120 may also be disposed at each side of the battery piece 101, and located between two second light reflecting structures 130.
In summary, the first light reflecting structure 120 and the second light reflecting structure 130 are disposed on the bearing surface c of the back plate body 110, wherein in the direction Z perpendicular to the bearing surface c, the thickness of the first light reflecting structure 120 is designed and the surface roughness of the top surface of the first light reflecting structure 120 away from the bearing surface c is specified, so that the probability of reflecting the light incident to the first light reflecting structure 120 to the light-facing surface a of the battery piece 101 is improved; the provision of the angular ranges of the angles between the first side d and the second side c of the convex structure 140 and the bearing surface c in the second light reflecting structure 130 and the design of the arrangement of the convex structure 140 are beneficial to improving the probability of reflecting the light incident to the second light reflecting structure 130 to the light facing surface a and the backlight surface b of the battery chip 101. The first light reflecting structure 120 and the second light reflecting structure 130 cooperate to facilitate improving the probability that the back plate 100 reflects the light incident on the back plate 100 onto the battery piece 101; on the other hand, compared with the flat and smooth back plate body 110, the first light reflecting structure 120 and the second light reflecting structure 130 with certain thicknesses are beneficial to reducing the length of the propagation path of the light incident into the gap between the adjacent battery pieces 101 and reflected onto the battery pieces 101, so as to improve the light intensity of the light received by the battery pieces 101, and both are beneficial to improving the utilization rate of the battery pieces 101 to the light, thereby improving the power generation of the battery pieces 101.
Fig. 12 to 14 are schematic cross-sectional structures of the photovoltaic module according to another embodiment of the present invention, fig. 15 and 16 are schematic top view structures of 2 kinds of battery strings according to another embodiment of the present invention, and the photovoltaic module according to this embodiment will be described in detail with reference to the accompanying drawings, and the same or corresponding parts as those of the above embodiments will not be described in detail.
Referring to fig. 12 and 14, the photovoltaic module 103 includes: a back plate 100 as in any of the above embodiments; the cover plate 102 and the plurality of battery pieces 101 between the cover plate 102 and the backboard body 110, the battery pieces 101 are provided with a light facing surface a and a backlight surface b which are opposite, a gap I is arranged between the adjacent battery pieces 101, and the first light reflecting structure 120 and the second light reflecting structure 130 are arranged in the gap I, and the extending direction of the first light reflecting structure is consistent with that of the second light reflecting structure.
The extending direction X (refer to fig. 1) of the first reflective structure 120 is consistent with the extending direction of the gap I, and the reflective surface f of the first reflective structure 120 is configured to diffuse the light incident on the reflective surface f in a direction away from the bearing surface c to form a first reflected light, and make the first reflected light propagate to the surface of the cover plate 102 and be reflected to the light-facing surface a for a second time; the second reflective structure 130 is configured to reflect the light incident on the first side d to form a second reflected light, and transmit the second reflected light to the backlight surface b or the light-facing surface a.
Light rays irradiated into the area without the battery piece 101 in the photovoltaic module 103 are reflected to the battery piece 101 through the first reflecting structure 120 and the second reflecting structure 130 in the back plate 100, so that the utilization rate of the battery piece 101 to the light rays is improved, and the power generation power of the battery piece 101 is improved, and the power generation power of the photovoltaic module 103 is improved.
Specifically, the reflecting surface f of the first reflecting structure 120 propagates the first reflected light to the cover plate 102, and then reflects the first reflected light to the light-directing surface a through the cover plate 102, so that most of the light incident to the first reflecting structure 120 can reach the light-directing surface a through twice reflection, and the light intensity of the light received by the battery piece 101 is improved by reducing the number of reflection times required for the light to reach the light-directing surface a, thereby being beneficial to improving the utilization rate of the light by the battery piece 101, and further improving the power generation of the battery piece 101.
The first side surface d of the second reflective structure 130 reflects the incident second reflected light to the backlight surface b or the light-facing surface a, and most of the light incident to the second reflective structure 130 can reach the battery piece 101 after reflection, so as to improve the light intensity of the light received by the battery piece 101, thereby being beneficial to improving the utilization rate of the light by the battery piece 101, and further improving the power generation of the battery piece 101.
The orthographic projection of the first light reflecting structure 120 on the bearing surface c is located in the orthographic projection of the gap I on the bearing surface c, and the orthographic projection of the second light reflecting structure 130 on the bearing surface c at least partially overlaps with the orthographic projection of the gap I on the bearing surface c. In some embodiments, the orthographic projection of the second light reflecting structure 130 on the bearing surface c is located in the orthographic projection of the gap I on the bearing surface c; in other embodiments, the orthographic projection of the second light reflecting structure 130 on the carrying surface c overlaps with the orthographic projection of the gap I on the carrying surface c, that is, the orthographic projection of the second light reflecting structure 130 on the carrying surface c is at least partially located in the orthographic projection of the battery piece 101 on the carrying surface c.
Specifically, a space is provided between the backlight surface b and the carrying surface c.
In some embodiments, the thickness of the first light reflecting structure 120 and the thickness of the second light reflecting structure 130 are not higher than the thickness of the interval in the direction perpendicular to the bearing surface c. In an example, referring to fig. 12, the thickness of the second light reflecting structure 130 is smaller than that of the interval, and the second light reflecting structure 130 mainly reflects the light incident on the second light reflecting structure 130 to the backlight surface b, so that the utilization rate of the light by the battery piece 101 is improved, and the power generation of the battery piece 101 is improved. In practical applications, the thickness of the second light reflecting structure may also be equal to the thickness of the space.
Further, in the direction Z perpendicular to the bearing surface c, the thickness of the first light reflecting structure 120 may be 5um to 20um, and the thickness of the second light reflecting structure 130 is not greater than the thickness of the first light reflecting structure 120. Specifically, as the thickness of the first light reflecting structure 120 increases, the shorter the propagation distance required for reflecting the light incident to the first light reflecting structure 120 to the light-facing surface a of the battery piece 101 is, the higher the reflectivity of the first light reflecting structure 120 increases, and the greater the light intensity of the light absorbed by the light-facing surface a of the battery piece 101 is, so as to increase the power generated by the battery piece 101, and in particular, when the thickness of the first light reflecting structure 120 is 20um, the reflectivity of the first light reflecting structure 120 may reach 90%. The thickness of the second reflective structure 130 is smaller than or equal to that of the first reflective structure 120, and the thickness is smaller, which is more favorable for reflecting light to the backlight surface b.
In other embodiments, the thickness of the first light reflecting structure 120 and the thickness of the second light reflecting structure 130 are greater than the thickness of the interval in the direction perpendicular to the bearing surface c.
For example, referring to fig. 13, when light is obliquely incident toward the first side d of the second light reflecting structure 130, the first side d of the second light reflecting structure 130 may reflect the incident light to the battery facing surface a or the backlight surface b. When the reflection point of the second reflected light is located at the bottom portion of the second reflective structure 130 near the bearing surface c, the second reflected light is reflected by the second reflective structure 130 to the bearing surface c, and then reflected by the bearing surface c to the backlight surface b of the battery piece 101 for a second time. In this way, the light conversion efficiency of the photovoltaic module 103 as a whole can be increased. It should be noted that, in fig. 13, only an acute angle formed between the first side d and the carrying surface c is taken as an example, where the reflecting point of the second reflected light is located at a bottom portion of the second reflecting structure 130 near the carrying surface c, the second reflected light is reflected by the second reflecting structure 130 onto the carrying surface c first, and then is reflected by the carrying surface c to the backlight surface b of the battery piece 101, and in practical application, the acute angle formed between the first side and the carrying surface may also be smaller than 45 °, so that when the reflecting point of the second reflected light is located at a bottom portion of the second reflecting structure near the carrying surface, the second reflected light is reflected by the second reflecting structure to the backlight surface of the battery piece at a time.
Referring to fig. 14, when the light is obliquely incident perpendicular to the first side d of the second reflective structure 130, the first side d reflects the light back onto the cover 102 along the incident light path, and is secondarily reflected to the light-facing surface a through the cover 102.
Referring to fig. 13 and 14 in combination, when the thickness of the second light reflecting structure 130 is greater than the thickness of the space, the second light reflecting structure 130 has the effect of reflecting light to the light facing surface a and the backlight surface b, so that both the light facing surface a and the backlight surface b of the battery chip 101 can absorb light reflected by the first side surface d. Moreover, the light-emitting surface a of the battery piece prepared by actual production has a larger light-emitting surface converting capability (capability of converting light energy into electric energy) than the backlight surface b, and when the thickness of the first reflective structure 120 and the thickness of the second reflective structure 130 are respectively 2-3 times of the thickness of the interval, the light-emitting surface a of the battery piece 101 absorbs the light reflected by the first side d, so that the light conversion efficiency of the whole photovoltaic module 103 is improved. When the ratio is greater than 3, the preparation difficulty and the cost are high, and the interference to the light which is normally and directly incident on the surface of the cell 101 is formed, so that the conversion efficiency of the photovoltaic module is reduced. The ratio of the thickness of the first light reflecting structure 120 to the thickness of the interval is also 2 to 3, and the thickness close to the second light reflecting structure 130 is maintained, so that the shielding of the light irradiated to the surfaces of each other can be reduced, and the stable power generation efficiency is ensured.
It should be noted that, in the photovoltaic module 103, the EVA film is filled in the interval formed by the first reflective structure 120 and the second reflective structure 130 and the battery piece 101 and the cover plate 102, the thickness of the interval between the backlight surface b and the bearing surface c depends on the thickness of the EVA film, the thickness range of the EVA film is 100um to 1000um, the thickness range of the interval is 100um to 1000um, and based on the thickness of the interval, when the ratio of the thickness of the first reflective structure 120 to the maximum thickness of the second reflective structure 130 is 2 to 3 times the thickness of the interval, the thickness of the first reflective structure 120 and the thickness range of the second reflective structure 130 are 200um to 3000um respectively. The thickness of the first light reflecting structure 120 is equal to that of the second light reflecting structure 130, so that the shielding phenomenon of the light rays irradiated to the surfaces of the first light reflecting structure and the second light reflecting structure can be completely eliminated, and the power generation efficiency is high.
In both embodiments, fig. 12 to 14 take the thickness of the first light reflecting structure 120 equal to the thickness of the second light reflecting structure 130 as an example, and in practical application, the thickness of the first light reflecting structure is not limited. In one example, the thickness of the first light reflecting structure may be no higher than the thickness of the space between the backlight surface and the bearing surface; in another example, the thickness of the first light reflecting structure may be higher than the thickness of the space between the backlight surface and the bearing surface.
In addition, in the above two embodiments, the first side d is inclined towards the direction approaching the first reflective structure 120, i.e. when the first side d is an inclined plane, the acute angle formed between the first side d and the bearing surface c may be in the range of 30 ° to 45 °, and when the inclination degree of the first side d is in the range, it is beneficial to improve the probability that the second reflected light beam incident on the first side d directly propagates to the backlight surface b, i.e. the second reflected light beam incident on the backlight surface b mostly does not need to be reflected by the bearing surface c secondarily, and the light beam can be directly reflected by the first side d to the backlight surface b, so that the light intensity reaching the backlight surface b due to the absorption of the light beam by the bearing surface c when the light beam is reflected secondarily by the bearing surface c is reduced. The number of reflections required for the light to reach the backlight surface b is reduced, so that the light intensity of the light received by the battery piece 101 is improved, thereby being beneficial to improving the utilization rate of the light by the battery piece 101, and further improving the generated power of the battery piece 101.
In some embodiments, referring to fig. 15, the plurality of battery pieces 101 are sequentially connected in series along a first direction to form a battery string 111, at least two battery strings 111 are sequentially arranged along a second direction intersecting the first direction, a first gap f is provided between adjacent battery strings 111, the first gap f extends along the first direction, and an extending direction X of the first light reflecting structure 120 (referring to fig. 12) and an extending direction of the second light reflecting structure 130 (referring to fig. 12) are consistent with the extending direction of the first gap, and it should be noted that the first direction is generally the extending direction X of the first light reflecting structure 120, and the second direction is generally the width direction Y of the first light reflecting structure 120.
It should be noted that, for the single battery string 111, the orthographic projection of the area where the dashed frame m and the dashed frame n do not overlap in the bearing surface c coincides with the orthographic projection of the first light reflecting structure 120 in the bearing surface c, and the orthographic projection of the second light reflecting structure 130 in the bearing surface c is located in the orthographic projection of the dashed frame n in the bearing surface c. Specifically, for a single battery string 111, the second light reflecting structure 130 may be disposed at each side of the battery string 111, and the first light reflecting structure 120 may be disposed at each side of the battery string 111 between two second light reflecting structures 130.
Further, referring to fig. 16, at least two battery strings 111 are further arranged in sequence along the first direction X, the battery sheets 101 (refer to fig. 12) of the adjacent battery strings 111 have a second gap h therebetween, the second gap h extends along the second direction, and the first light reflecting structure 120 and the second light reflecting structure 130 also extend along the second direction, and the first gap f and the second gap h together form a gap I (refer to fig. 12), it should be noted that, for the single battery string 111 in fig. 13, the relative positional relationship among the first light reflecting structure 120, the second light reflecting structure 130 and the battery strings 111 is the same as that illustrated in fig. 12.
In fig. 15 and 16, the battery string 111 is taken as an example, and in practical applications, a plurality of single battery pieces 101 may be sequentially arranged along the first direction and/or the second direction.
In summary, the first light reflecting structure 120 and the second light reflecting structure 130 in the photovoltaic module 103 are beneficial to improving the probability of reflecting light onto the battery piece 101, so as to improve the utilization rate of the battery piece 101 to light, thereby improving the power generated by the battery piece 101 and improving the power generated by the photovoltaic module 103.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the invention and that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is therefore intended to be limited only by the appended claims.

Claims (22)

1. A backsheet for use in a photovoltaic module having at least two adjacent cells with a gap between adjacent sides of the cells, the cells having opposing light-directing and backlight surfaces, the backsheet comprising:
the back plate body is provided with a bearing surface, and the bearing surface is the surface of the back plate body facing the battery piece;
The first light reflecting structure is positioned on the bearing surface, the top surface of the first light reflecting structure, which is far away from the bearing surface, is a reflecting surface, and the reflecting surface is used for enabling light rays incident on the reflecting surface to be diffusely reflected in a direction far away from the bearing surface so as to form
The extending direction of the first reflecting structure is consistent with the extending direction of the gap, the orthographic projection of the first reflecting structure on the bearing surface is positioned in the orthographic projection of the gap on the bearing surface, and the first reflecting structure is used for enabling the first reflecting light to be transmitted to the light facing surface;
the second light reflecting structure is positioned on at least one side of the width direction of the first light reflecting structure, the second light reflecting structure comprises a protruding structure, the side surface of the protruding structure, which faces away from the first light reflecting structure, is a first side surface, the first side surface is a plane or an arc surface, the first side surface is inclined towards the direction close to the first light reflecting structure, the second light reflecting structure is used for reflecting light rays incident to the first side surface to form second reflected light rays, and the second light reflecting structure is used for enabling the second reflected light rays to propagate to the light facing surface or the backlight surface;
and if the first side surface is an arc surface, the first side surface is recessed towards the direction close to the first reflecting structure.
2. The back plate of claim 1, wherein the first side surface is planar and the angle between the first side surface and the bearing surface is between 30 ° and 45 °.
3. The back plate of claim 1, wherein a surface of the first side is provided with a saw tooth structure.
4. The back plate of claim 1, wherein the number of said convex structures is at least two, each of said convex structures is arranged in sequence in a direction along said first light reflecting structure toward said second light reflecting structure, and the thicknesses of adjacent ones of said convex structures in a direction perpendicular to said carrying surface are reduced in sequence.
5. The back plate of claim 1, wherein the angle between the sides of the reflective surface on both sides in the width direction and the bearing surface is less than or equal to 90 °.
6. The back plate of claim 5, wherein said reflective surface is parallel to said carrying surface and lateral sides of said reflective surface on either side of the width of said reflective surface are perpendicular to said carrying surface.
7. The back plate of claim 1, wherein the thickness of the first light reflecting structure is not less than the thickness of the second light reflecting structure in a direction perpendicular to the bearing surface.
8. The back sheet of claim 1, wherein a ratio of a bottom width of the first light reflecting structure to a bottom width of the second light reflecting structure in a direction in which the second light reflecting structure is directed toward the first light reflecting structure is 0.8 to 1.2.
9. The back panel of claim 1, further comprising pyramid structures located on the bearing surface and on a side of the second light reflecting structure opposite the first light reflecting structure.
10. A back plate according to claim 9, wherein the angle between the side faces of the pyramid structures and the bearing surface is 15 ° to 45 °.
11. The back plate of claim 1, wherein the back plate body comprises a fluorine film and a PET film which are stacked, and the first light reflecting structure and the second light reflecting structure are both printed and coated on the bearing surface of the PET film on the side opposite to the fluorine film.
12. The backsheet of claim 1 wherein the material of the first light reflecting structure and the second light reflecting structure is a mixture of tetrafluoroethylene, titanium white, epoxy, light stabilizer and silane coupling agent or a mixture of polyvinylidene fluoride, titanium white, epoxy, light stabilizer and silane coupling agent.
13. The backsheet of claim 1 wherein the reflectivity of the first light reflecting structure and the reflectivity of the second light reflecting structure are both greater than the reflectivity of the backsheet body.
14. The back plate of claim 1, wherein the reflective surface has a roughness Ra of greater than or equal to 5.
15. A photovoltaic module, comprising:
a backsheet as claimed in any one of claims 1 to 14;
The solar cell comprises a cover plate and a plurality of cell pieces arranged between the cover plate and the back plate body, wherein each cell piece is provided with a light facing surface and a backlight surface, a gap is arranged between every two adjacent cell pieces, and the first light reflecting structure and the second light reflecting structure are arranged in the gap and have the same extension direction as the extension direction of the gap.
16. The photovoltaic module of claim 15, wherein the orthographic projection of the first light reflecting structure onto the bearing surface is located in the orthographic projection of the gap onto the bearing surface, and wherein the orthographic projection of the second light reflecting structure onto the bearing surface at least partially overlaps the orthographic projection of the gap onto the bearing surface.
17. The photovoltaic module of claim 15, wherein the backlight surface and the carrier surface have a spacing therebetween, and wherein the thickness of the first light reflecting structure and the thickness of the second light reflecting structure are not greater than the thickness of the spacing in a direction perpendicular to the carrier surface.
18. The photovoltaic module of claim 17, wherein the first light reflecting structure has a thickness of 5um to 20um and the second light reflecting structure has a thickness not greater than the thickness of the first light reflecting structure.
19. The photovoltaic module of claim 15, wherein a space is provided between the backlight surface and the carrier surface, and the thickness of the first light reflecting structure and the thickness of the second light reflecting structure are respectively 2-3 times the thickness of the space in a direction perpendicular to the carrier surface.
20. The photovoltaic module of claim 19, wherein the thickness of the first light reflecting structure and the thickness of the second light reflecting structure are equal, respectively, from 200um to 3000um.
21. The photovoltaic module of claim 15, wherein a plurality of the battery pieces are sequentially connected in series along a first direction to form a battery string, at least two battery strings are sequentially arranged along a second direction intersecting the first direction, a first gap is formed between adjacent battery strings, the first gap extends along the first direction, and the extending direction of the first light reflecting structure, the extending direction of the second light reflecting structure are consistent with the extending direction of the first gap.
22. The photovoltaic module of claim 21, wherein at least two of the cell strings are further arranged in sequence along the first direction, wherein a second gap is provided between the cell sheets of adjacent cell strings, wherein the second gap extends along the second direction, and wherein the first light reflecting structure and the second light reflecting structure further extend along the second direction.
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