A photovoltaic module

Abstract

The utility model provides a kind of photovoltaic module, including cell piece and back glass, back glass is located at the side of cell piece, and installation hole is set on back glass in through, and chamfer structure is set in the hole rim of installation hole, and compressive stress layer is formed on the surface of back glass, and compressive stress layer at least covers the hole rim of installation hole and is provided with chamfer structure.The utility model adds chamfer at the hole rim of installation hole of back glass, can significantly alleviate the stress concentration of the opening position of back glass, neither introduces additional risk, nor increases cost.Meanwhile, the compressive stress layer covering opening position is formed on the surface of back glass, further improves the crack resistance of opening position, avoids cracking due to stress concentration in the process of installation or use, to effectively improve the reliability and service life of photovoltaic module.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, and in particular to a photovoltaic module. Background Technology

[0002] Photovoltaic modules are the core of solar power generation systems. The glass on their back must protect the solar cells and internal circuitry, and junction box mounting holes must be cut in appropriate locations to facilitate electrical connections and signal transmission. Currently, these holes are mostly made by mechanical drilling or laser cutting, but stress concentration is very likely to occur at the edges of the openings. Statistics show that more than half of glass cracks start from these sharp corners, seriously affecting the lifespan of the modules and power generation efficiency.

[0003] To reduce stress concentration, there are two main existing approaches: one is to increase the aperture size, which reduces edge stress but increases the exposed area of ​​the encapsulation material, raising the risk of encapsulation failure by about 18%; the other is to fill the aperture with a special colloid, which can relieve stress but increases the cost per watt of photovoltaic modules, making it unsuitable for large-scale applications.

[0004] CN107129160B proposed a chemically strengthened glass process: after grinding the glass surface, a compressive stress layer is formed by precisely controlling parameters such as texture direction index, silanol group content, hydrogen concentration, and roughness, thereby improving the overall strength of the glass. However, this process does not provide a specific strengthening method for the mounting hole, a local geometric abrupt change area. Other heat treatment or chemical strengthening methods also focus on the overall strength of the glass, neglecting the special stress distribution at the opening.

[0005] In summary, there is still a lack of technical solutions that can significantly reduce stress concentration at junction box mounting holes and improve local strength without significantly increasing costs or introducing additional risks. Therefore, developing new targeted strengthening technologies has become an urgent need to improve the reliability and lifespan of photovoltaic modules. Utility Model Content

[0006] The purpose of this utility model is to provide a photovoltaic module that can solve the problem of stress concentration at the opening of the back glass of existing photovoltaic modules without bringing additional risks and increasing costs.

[0007] To address the aforementioned technical problems, this utility model provides a photovoltaic module, comprising:

[0008] Battery cells;

[0009] The back glass is located on one side of the battery cell. A mounting hole is provided through the back glass. A chamfered structure is provided at the edge of the mounting hole. A compressive stress layer is formed on the surface of the back glass. The compressive stress layer at least covers the edge of the mounting hole where the chamfered structure is provided.

[0010] In some embodiments, the mounting hole is provided with the chamfered structure at the end away from the battery cell; and / or, the mounting hole is provided with the chamfered structure at the end near the battery cell.

[0011] In some embodiments, the compressive stress layer covers the surface of the back glass near the battery cell and the surface away from the battery cell.

[0012] In some embodiments, the chamfered structure has a dimension H in the thickness direction of the back glass, the thickness of the back glass is T, and satisfies the following relationship:

[0013] 0.15T≤H≤0.25T.

[0014] In some embodiments, 0.18T≤H≤0.22T.

[0015] In some embodiments, the angle between the chamfered surface of the chamfered structure and the plane containing the back glass is α, and satisfies the following relationship:

[0016] 25°≤α≤50°.

[0017] In some embodiments, 32°≤α≤38°.

[0018] In some embodiments, the chamfer structure is an arc-shaped chamfer structure, the radius of curvature of the arc-shaped chamfer structure is R, and it satisfies the following relationship:

[0019] R≥0.15mm.

[0020] In some embodiments, the roughness of the chamfered surface of the chamfered structure is Ra, and satisfies the following relationship:

[0021] Ra≤0.8μm.

[0022] In some embodiments, the compressive stress value of the compressive stress layer is not less than 100 MPa.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention adds a chamfer to the edge of the mounting holes on the back glass, which significantly alleviates stress concentration at the opening locations on the back glass without introducing additional risks or increasing costs. Simultaneously, a compressive stress layer is formed on the surface of the back glass covering the opening locations, further enhancing the crack resistance of these areas and preventing cracking due to stress concentration during installation or use. This effectively improves the reliability and lifespan of the photovoltaic modules. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0026] Figure 1 This is a cross-sectional view of the photovoltaic module in an embodiment of this utility model;

[0027] Figure 2 for Figure 1 Cross-sectional view of the rear glass panel;

[0028] Figure 3 A comparison chart of four-point bending test data for back glass with and without chamfering.

[0029] Explanation of reference numerals in the accompanying drawings of this utility model:

[0030] Photovoltaic module 100, solar cell 1, back glass 2, mounting hole 21, chamfer structure 22, first chamfer structure 22a, second chamfer structure 22b, chamfer surface 221, compressive stress layer 23, back film layer 3, connecting hole 31, front glass 4, front film layer 5.

[0031] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0035] Existing photovoltaic modules suffer from stress concentration at the openings on the back glass, leading to over 50% of glass cracks originating from the sharp corners of these openings. Therefore, this invention provides a photovoltaic module... Figure 1 and Figure 2 A preferred embodiment of the photovoltaic module provided by this utility model is shown.

[0036] Please see Figure 1 and Figure 2 In some embodiments, the photovoltaic module 100 includes a solar cell 1 and a back glass 2. The back glass 2 is located on one side of the solar cell 1. A mounting hole 21 is provided through the back glass 2. A chamfered structure 22 is provided at the edge of the mounting hole 21. A compressive stress layer 23 is formed on the surface of the back glass 2. The compressive stress layer 23 at least covers the edge of the mounting hole 21 where the chamfered structure 22 is provided.

[0037] Specifically, a photovoltaic module 100 typically includes a front glass 4, a front film layer 5, a solar cell 1, a back film layer 3, and a back glass 2, which are stacked sequentially. The back film layer 3 and the back glass 2 are located on the backlight side of the solar cell 1, and the back glass 2 is fixed to the backlight surface of the solar cell 1 by the back film layer 3. The front glass 4 and the front film layer 5 are located on the light-receiving side of the solar cell 1, and the front glass 4 is fixed to the light-receiving surface of the solar cell 1 by the front film layer 5. The thickness direction of the back glass 2 is defined as vertical, with the side of the back glass 2 closer to the solar cell 1 being the upper side and the side of the back glass 2 furthest from the solar cell 1 being the lower side.

[0038] One or more mounting holes 21 are provided on the back glass 2, extending vertically through the back glass 2, each mounting hole 21 forming an opening on the back glass 2. The specific function of the mounting holes 21 can be set according to the actual situation; for example, the mounting holes 21 can be junction box mounting holes, etc. Optionally, please refer to... Figure 1 and Figure 2 In some embodiments, the mounting hole 21 is a junction box mounting hole, and a through hole 31 communicating with the mounting hole 21 is provided through the back film layer 3. The mounting hole 21 is used to install the junction box (not shown in the figure) of the photovoltaic module 100. The following description will take the mounting hole 21 as a junction box mounting hole as an example. The specific material of the back glass 2 can be set according to the actual situation. For example, the back glass 2 can be made of materials such as soda-lime glass.

[0039] The mounting hole 21 has an upper edge and a lower edge. The upper edge of the mounting hole 21 is located at the connection between the inner surface of the mounting hole 21 and the upper surface of the back glass 2, and the lower edge of the mounting hole 21 is located at the connection between the inner surface of the mounting hole 21 and the lower surface of the back glass 2. A chamfered structure 22 is provided at one end of the mounting hole 21 near the battery cell 1 and / or the other end away from the battery cell 1. That is, the upper edge and / or lower edge of the mounting hole 21 are provided with a chamfered structure 22. The chamfered structure 22 at the lower edge of the mounting hole 21 is defined as the first chamfered structure 22a, and the chamfered structure 22 at the upper edge of the mounting hole 21 is defined as the second chamfered structure 22b. Therefore, the back glass 2 can have only the first chamfered structure 22a or the second chamfered structure 22b; or it can have both the first chamfered structure 22a and the second chamfered structure 22b simultaneously. By providing a first chamfer structure 22a and / or a second chamfer structure 22b at the mounting hole 21, stress concentration at the opening of the back glass 2 can be significantly alleviated without introducing additional risks or increasing costs. For example, please refer to... Figure 3 The four-point bending test results of the chamfered back glass (i.e., back glass 2 in this application) are significantly better than those of the unchamfered back glass (i.e., the back glass in the prior art).

[0040] The back glass 2 undergoes heat treatment or chemical strengthening processes to form a compressive stress layer 23 on its surface. This compressive stress layer 23 covers the upper and / or lower edges of the mounting holes 21, ensuring coverage of the openings in the back glass 2. This further enhances the crack resistance of the openings, preventing cracking due to stress concentration during installation or use. This reduces the breakage rate of the back glass 2 and lowers the LCOE (Levelized Cost of Electricity) over the lifespan of the photovoltaic module 100. For example, compared to traditional solutions, the photovoltaic module 100 can reduce the glass breakage rate by over 90% and decrease the LCOE by $0.021 / kWh over its lifespan.

[0041] This invention adds a chamfer to the edge of the mounting hole 21 on the back glass 2, which can significantly alleviate stress concentration at the opening of the back glass 2 without introducing additional risks or increasing costs. At the same time, a compressive stress layer 23 is formed on the surface of the back glass 2 to cover the opening, further improving the crack resistance of the opening and preventing cracking caused by stress concentration during installation or use, thereby effectively improving the reliability and service life of the photovoltaic module 100.

[0042] As described above, the upper and / or lower edges of the mounting hole 21 are provided with chamfered structures 22. When the lower edge of the mounting hole 21 is provided with a first chamfered structure 22a, the first chamfered structure 22a is located at the lower edge of the mounting hole 21, which helps to reduce the impact of direct sunlight on the first chamfered structure 22a and extend the service life of the mounting hole 21.

[0043] Optionally, please refer to Figure 1 and Figure 2 In some embodiments, the end of the mounting hole 21 away from the battery cell 1 is provided with a chamfered structure 22, and the end of the mounting hole 21 close to the battery cell 1 is provided with a chamfered structure 22.

[0044] Specifically, a first chamfer structure 22a and a second chamfer structure 22b are respectively provided at the lower edge and the upper edge of the mounting hole 21. When the mounting hole 21 is chamfered by the chamfering grinding wheel, the chamfering grinding wheel simultaneously chamfers the lower edge and the upper edge of the mounting hole 21, so that the first chamfer structure 22a and the second chamfer structure 22b are formed simultaneously in one processing of the chamfering grinding wheel.

[0045] Optionally, please refer to Figure 1 and Figure 2 In some embodiments, the chamfered structure 22 has a dimension H in the thickness direction of the back glass 2, the thickness of the back glass 2 is T, and satisfies the following relationship:

[0046] 0.15T≤H≤0.25T (1).

[0047] Specifically, the thickness T of the back glass 2 can be set according to actual conditions. For example, the thickness T of the back glass 2 can be 2.0 mm. The dimension of the chamfer structure 22 in the thickness direction of the back glass 2 is the chamfer depth of the chamfer structure 22. When only the first chamfer structure 22a is provided on the back glass 2, H is the vertical dimension of the first chamfer structure 22a; when only the second chamfer structure 22b is provided on the back glass 2, H is the vertical dimension of the second chamfer structure 22b; when both the first chamfer structure 22a and the second chamfer structure 22b are provided on the back glass 2, H is the sum of the vertical dimensions of the first chamfer structure 22a and the second chamfer structure 22b. For example, please refer to... Figure 1 and Figure 2 In some embodiments, the back glass 2 is provided with a first chamfer structure 22a and a second chamfer structure 22b. The first chamfer structure 22a has a vertical dimension of H1, and the second chamfer structure 22b has a vertical dimension of H2. Then the chamfer depth H of the chamfer structure 22 is H1 + H2.

[0048] Condition (1) specifies the range of the ratio between the chamfer depth H of the chamfer structure 22 and the thickness T of the back glass 2. Within the range defined by condition (1), the chamfer structure 22 can be guaranteed to have sufficient strength without excessively weakening the overall structural strength of the back glass 2. More preferably, 0.18T≤H≤0.22T. For example, the chamfer depth H of the chamfer structure 22 can be 0.15T, 0.16T, 0.17T, 0.18T, 0.19T, 0.20T, 0.21T, 0.22T, 0.23T, 0.24T, or 0.25T, etc.

[0049] Optionally, please refer to Figure 1 and Figure 2 In some embodiments, the angle between the chamfered surface 221 of the chamfered structure 22 and the plane containing the back glass 2 is α, and satisfies the following relationship:

[0050] 25°≤α≤50° (2).

[0051] Specifically, condition (2) specifies the range of the angle α between the chamfered surface 221 and the plane (i.e., the horizontal plane) where the back glass 2 is located. Within the range defined by condition (2), the stress distribution at the mounting hole 21 is relatively uniform, which can effectively avoid glass breakage caused by stress concentration. More preferably, 32°≤α≤38°. For example, the angle α between the chamfered surface 221 and the horizontal plane can be 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, or 50°, etc.

[0052] The chamfer structure 22 can be a planar chamfer structure or an arc-shaped chamfer structure, etc. Optionally, please refer to Figure 1 and Figure 2 In some embodiments, the chamfer structure 22 is an arc-shaped chamfer structure with a radius of curvature of R, and satisfies the following relationship:

[0053] R≥0.15mm (3).

[0054] Specifically, condition (3) specifies the range of values ​​for the radius of curvature R of the chamfer structure 22. Within the range defined by condition (3), the stress distribution at the mounting hole 21 is relatively uniform, which can effectively avoid glass breakage caused by stress concentration.

[0055] Optionally, please refer to Figure 1 and Figure 2 In some embodiments, the roughness of the chamfered surface 221 of the chamfered structure 22 is Ra, and satisfies the following relationship:

[0056] Ra≤0.8μm (4).

[0057] Specifically, condition (4) specifies the range of roughness Ra of the chamfered surface 221. Within the range defined by condition (4), this low-roughness surface treatment of the chamfered surface 221 can effectively reduce the generation of microcracks and improve the strength and durability of the mounting hole 21. The roughness of the chamfered surface 221 can be achieved through a precision grinding process. For example, a coarse grinding wheel is used for preliminary grinding, followed by a fine grinding wheel for fine grinding, and finally a polishing wheel is used for surface polishing, so that the chamfered surface 221 can meet the surface roughness requirement of Ra≤0.8μm.

[0058] When the junction box is installed on the mounting hole 21, the connecting part of the junction box fits tightly against the chamfered surface 221, forming a stable connection. Because the chamfered surface 221 has low roughness and a smooth surface, it increases the contact area between the junction box and the back glass 2, improving the stability and sealing of the connection.

[0059] A compressive stress layer 23 is formed on the surface of the back glass 2. This compressive stress layer 23 can be formed on a portion of the upper surface of the back glass 2, or it can be formed on the entire upper surface of the back glass 2. Similarly, the compressive stress layer 23 can be formed on a portion of the lower surface of the back glass 2, or it can be formed on the entire lower surface of the back glass 2. Optionally, in this embodiment, the compressive stress layer 23 covers both the surface of the back glass 2 closest to the battery cell 1 and the surface furthest from the battery cell 1.

[0060] Specifically, after the mounting holes 21 and chamfered structure 22 on the back glass 2 are formed, the entire back glass 2 can be processed using techniques such as tempering to form a compressive stress layer 23 on the upper and lower surfaces of the back glass 2, ensuring that the compressive stress layer 23 covers the chamfered surface 221. The thickness of the compressive stress layer 23 can be 0.1T to 0.3T; for example, the thickness of the compressive stress layer 23 can be approximately 0.2T. The following description will use the tempering process to form the compressive stress layer 23 on the back glass 2 as an example.

[0061] Optionally, please refer to Figure 1 and Figure 2 In some embodiments, the compressive stress value of the compressive stress layer 23 is not less than 100 MPa.

[0062] Specifically, the tempered back glass 2 has higher mechanical strength and impact resistance. In particular, the chamfered part of the mounting hole 21 (i.e., the chamfered structure 22) has a compressive stress layer 23 with a compressive stress value of not less than 100MPa, which greatly improves the crack resistance at the mounting hole 21 and can effectively prevent cracking caused by stress concentration during installation or use.

[0063] The back glass 2 of the photovoltaic module 100, through a specific chamfer design and surface treatment, can effectively alleviate stress concentration at the opening of the back glass 2, improve the strength and stability of the junction box installation structure, prevent glass breakage, and improve the safety and service life of the photovoltaic module 100. Several specific settings for the back glass 2 will be given below.

[0064] First Embodiment

[0065] The mounting hole 21 has a diameter of 10 mm. The back glass 2 has a thickness of 3.2 mm, so the chamfer depth of the chamfer structure 22 ranges from 0.576 mm to 0.704 mm, with a preferred value of 0.64 mm. The chamfer surface 221 has an angle of 45° with the horizontal plane, is a frustum-shaped cone, and has a roughness of 0.8 μm.

[0066] The specific steps for tempering the back glass 2 include: heating the back glass 2 to 620°C, holding it at that temperature for 10 minutes, and then rapidly cooling it to room temperature at a cooling rate of 80°C / minute. Through this tempering process, a compressive stress layer 23 is formed on the surface of the back glass 2. The thickness of the compressive stress layer 23 is approximately 20% of the thickness of the back glass 2, and the compressive stress value reaches 120 MPa.

[0067] Second Embodiment

[0068] The mounting hole 21 has a diameter of 10 mm. The back glass 2 has a thickness of 4.0 mm, so the chamfer depth of the chamfer structure 22 ranges from 0.72 mm to 0.88 mm, with a preferred value of 0.80 mm. The chamfer surface 221 has an angle of 45° with the horizontal plane, is a frustum-shaped cone, and has a roughness of 0.5 μm.

[0069] The specific steps for tempering the back glass 2 include: heating the back glass 2 to 620°C, holding it at that temperature for 10 minutes, and then rapidly cooling it to room temperature at a cooling rate of 80°C / minute. Through this tempering process, a compressive stress layer 23 is formed on the surface of the back glass 2. The thickness of the compressive stress layer 23 is approximately 20% of the thickness of the back glass 2, and the compressive stress value reaches 150 MPa.

[0070] Third Embodiment

[0071] The mounting hole 21 has a diameter of 10 mm. The back glass 2 has a thickness of 2.5 mm, so the chamfer depth of the chamfer structure 22 ranges from 0.45 mm to 0.55 mm, with a preferred value of 0.50 mm. The chamfer surface 221 has an angle of 45° with the horizontal plane, is a frustum-shaped cone, and has a roughness of 0.7 μm.

[0072] Because the back glass 2 is relatively thin, the tempering temperature is reduced to 600℃, the holding time is extended to 15 minutes, and the cooling rate is reduced to 60℃ / minute to prevent deformation or breakage of the back glass 2 during tempering. This tempering process forms a compressive stress layer 23 on the surface of the back glass 2, with a thickness approximately 20% of the thickness of the back glass 2 and a compressive stress value reaching 110 MPa.

[0073] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of the specification and drawings of this utility model, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A photovoltaic module, characterized in that, include: Battery cells; The back glass is located on one side of the battery cell. A mounting hole is provided through the back glass. A chamfered structure is provided at the edge of the mounting hole. A compressive stress layer is formed on the surface of the back glass. The compressive stress layer at least covers the edge of the mounting hole where the chamfered structure is provided.

2. The photovoltaic module according to claim 1, characterized in that, The mounting hole is provided with the chamfered structure at the end away from the battery cell; and / or, the mounting hole is provided with the chamfered structure at the end near the battery cell.

3. The photovoltaic module according to claim 1, characterized in that, The compressive stress layer covers the surface of the back glass near the battery cell and the surface away from the battery cell.

4. The photovoltaic module according to claim 1, characterized in that, The chamfered structure has a dimension H in the thickness direction of the back glass, and the thickness of the back glass is T, and satisfies the following relationship: 0.15T≤H≤0.25T.

5. The photovoltaic module according to claim 4, characterized in that, 0.18T≤H≤0.22T.

6. The photovoltaic module according to claim 1, characterized in that, The angle between the chamfered surface of the chamfered structure and the plane containing the back glass is α, and satisfies the following relationship: 25°≤α≤50°。 7. The photovoltaic module according to claim 6, characterized in that, 32°≤α≤38°。 8. The photovoltaic module according to claim 1, characterized in that, The chamfer structure is an arc-shaped chamfer structure with a radius of curvature of R, and satisfies the following relationship: R≥0.15mm.

9. The photovoltaic module according to claim 1, characterized in that, The roughness of the chamfered surface of the chamfered structure is Ra, and it satisfies the following relationship: Ra≤0.8μm.

10. The photovoltaic module according to claim 1, characterized in that, The compressive stress value of the compressive stress layer is not less than 100 MPa.

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