Thermo-sensitive exhaust boss pad for photovoltaic module lamination process and use method of thermo-sensitive exhaust boss pad

Abstract

The invention discloses a thermosensitive exhaust boss pad for a photovoltaic module lamination process and a use method of the thermosensitive exhaust boss pad, and belongs to the technical field of photovoltaic module packaging. The boss pad comprises a flexible substrate layer and a boss array arranged on the surface of the substrate layer, and the substrate layer is provided with a plurality of hole structures used for guiding flow and exhausting air; and the boss array is distributed in a plane in a manner that the height is gradually reduced from the central area to the peripheral area, and is made of a material with temperature-related mechanical properties. In the low-temperature stage of the lamination process, the bosses keep the supporting strength, and exhaust micro-channels are formed between the substrate layer and an upper lamination medium; in the medium-temperature stage, the boss material is softened and subjected to graded collapse, so that laminated interfaces are gradually attached; and in the high-temperature stage, the boss is further collapsed to be flat, so that the interface tends to be flat. Through the synergistic effect of the structure and material characteristics, interface gas can be guided to be discharged in the photovoltaic module laminating process, and the pressure distribution of the laminated structure is improved, so that the probability of occurrence of defects such as air trapping and poor local attachment is reduced. The vacuum laminating device is simple in structural form and can be applied to existing vacuum laminating equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic module encapsulation manufacturing, in particular to an auxiliary pad for photovoltaic module lamination process and a method of using the same. BACKGROUND

[0002] The lamination encapsulation process of photovoltaic modules is a key step in the module manufacturing process, and the exhaust quality and uniformity of pressure directly affect the appearance quality of the module and the structural reliability of the cell sheet. With the continuous increase in the size of photovoltaic modules and the continuous thinning of cell sheets, the requirements for exhaust efficiency and uniformity of lamination are increasingly strict.

[0003] In the existing vacuum lamination process, large-size modules are prone to edge region first lamination to form an edge during the initial vacuum pumping, which limits the gas discharge path in the central region, thereby possibly causing gas trapping and bubble defects. In addition, thin cell sheets are sensitive to local stress under heating and pressure conditions, and if the interface pressure distribution is uneven, structural damage such as hidden cracks or micro-cracks may occur.

[0004] The auxiliary pads commonly used in the prior art, such as roughened silica gel plates and isolation cloths, are mostly uniform structures, and their mechanical properties remain basically constant during the lamination process, and it is usually difficult to meet the requirements of maintaining the exhaust path at low temperature and flexible lamination at high temperature. Therefore, in the application of photovoltaic module lamination, an auxiliary pad with adjustable structure and performance according to process temperature is still needed to improve the continuity of the exhaust path and the uniformity of the pressure during lamination, so as to meet the encapsulation requirements of large-size modules and thin cell sheets. SUMMARY

[0005] The present application aims to solve the problems of easy blockage of exhaust path, central gas trapping, and uneven interface pressure distribution leading to hidden cracks in thin cell sheets in the lamination process of photovoltaic modules, and provides a heat-sensitive exhaust boss pad for photovoltaic module lamination process and a method of using the same. By constructing a boss structure that can dynamically adjust the mechanical state under the action of temperature, the exhaust path is maintained at low temperature and flexible lamination is achieved at high temperature, thereby improving the exhaust efficiency and uniformity of pressure during lamination.

[0006] To achieve the above-mentioned purpose, the present application proposes the following technical solutions:

[0007] A heat-sensitive exhaust boss pad for photovoltaic module lamination process, comprising a flexible substrate layer and a heat-sensitive boss array arranged on the surface of the flexible substrate layer; wherein the flexible substrate layer is provided with a plurality of hole structures for guiding exhaust; the heat-sensitive boss array is composed of a plurality of bosses arranged along the plane of the substrate layer, the bosses have a height gradient gradually decreasing from the central region to the peripheral region in the plane; the bosses are made of a material with temperature-dependent mechanical properties, so that they maintain support rigidity at low temperature, soften and collapse at medium temperature, and basically collapse to form a conforming interface at high temperature.

[0008] Further, the flexible substrate layer can be a net-like or honeycomb-like structure, and the holes thereof are regularly arranged polygonal holes for accommodating material deformation when the bosses collapse. Further, the bosses in the heat-sensitive boss array can be divided into a central region, an intermediate region and an edge region, and the heights of the three regions decrease in turn to form a macroscopic gradient flow guiding structure. Further, the boss material can be selected from thermoplastic elastomers, phase change silica gel or polymer materials with a significant decrease in storage modulus with the increase of temperature, so as to realize heat-sensitive response. Further, the flexible substrate layer and the boss array can be integrally formed, and at least one of an auxiliary support layer, a heat insulation layer or a reinforcing layer can be arranged between the two to form a composite structure. Further, a frame reinforcing region can be arranged at the outer edge of the flexible substrate layer, and positioning holes or positioning marks can be arranged at the four corners of the boss pad for assembly and positioning.

[0009] In addition, the application also discloses a use method of the heat-sensitive exhaust boss pad, comprising the following steps:

[0010] (1) preparing a photovoltaic module stack structure to be laminated (including a structure integrally stacked by a glass plate, an adhesive film, a cell piece and a back plate).

[0011] (2) arranging the heat-sensitive exhaust boss pad on the upper surface of the stack structure, and contacting the upper laminating medium of the laminating machine.

[0012] (3) performing the processes of vacuumizing, heating and pressurizing in the laminating machine.

[0013] (4) in the low-temperature vacuum stage, the gradient boss array maintaining rigidity is used to form micro-channels from the central region to the periphery in the interface, and guide the exhaust of interface gas.

[0014] (5) in the medium-temperature stage, with the increase of temperature, the boss material gradually softens and collapses, so that the conforming process is more gentle, and peak stress is avoided.

[0015] (6) in the high-temperature pressurizing stage, the bosses basically collapse and fill into the holes of the substrate layer, so that the upper surface is changed into a flat and uniform flexible buffer layer, and the flexible conforming and uniform pressure transmission of the module are realized.

[0016] Compared with the prior art, the application has the following beneficial effects:

[0017] The present application can improve the phenomenon that the air in the center of the large-size assembly is difficult to be discharged by setting the heat-sensitive bump array with macro height gradient on the flexible substrate layer, so that the bumps can support the interface micro gap of the laminated structure to form the gradually open exhaust path from the center area to the outer edge area of the assembly during the vacuum pumping and low temperature stage.

[0018] The bumps in the present application are made of materials with temperature-dependent mechanical response characteristics, and the storage modulus of the bumps decreases significantly with the increase of temperature, so that the bumps sequentially experience three stages of "rigid support-soft deformation-overall collapse" during the heating process. This dynamic response behavior effectively separates the exhaust process and the lamination process in time, avoids the problem that the exhaust path is closed due to the early lamination of the traditional pad material, and reduces the local stress peak value of the laminated interface.

[0019] The flexible substrate layer in the present application can be made of heat-resistant elastomers, silicone rubber, reinforced fiber mesh and other materials, and is provided with regular grid or honeycomb hole structure. When the bumps collapse at high temperature, the deformed material can partially enter the holes, so that the pad surface restores to a flat and continuous pressing interface, thereby improving the pressure uniformity of the assembly laminated at high temperature and high pressure, and significantly reducing the risk of hidden cracking, micro cracking and damage of the thinned battery sheet during the lamination process.

[0020] The present application can improve the local edge sealing effect of the assembly edge area by the synergistic effect of the frame reinforcement area of the flexible substrate layer and the gradient bump exhaust structure, so that the exhaust process of the gas from the center to the periphery is more smooth, which is beneficial to further reduce the amount of residual gas in the large-size assembly, and improve the appearance quality and lamination reliability of the assembly.

[0021] The heat-sensitive exhaust bump pad of the present application can be directly arranged above the laminated structure of the assembly as an independent process auxiliary material, which is compatible with the existing vacuum lamination equipment without the need for structural modification of the equipment; the one-piece structure is convenient for large-scale manufacturing and is suitable for process adaptation of different specifications of assemblies, which has good engineering application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will be further described below in conjunction with the drawings and specific embodiments.

[0023] Figure 1 It is a schematic diagram of the overall structure of the heat-sensitive exhaust bump pad of the present application.

[0024] Figure 2 It is a schematic diagram of the overall structure of the heat-sensitive exhaust bump pad of the present application.

[0025] Figure 3 It is a schematic diagram of the overall structure of the heat-sensitive exhaust bump pad of the present application.

[0026] Figure 4 Figure 1 is a schematic diagram of the cooperation of the heat-sensitive exhaust boss pad and the photovoltaic module laminated structure of the present application.

[0027] Figure 5 Figure 2 is a schematic diagram of the use of the heat-sensitive exhaust boss pad in the laminating process of the present application.

[0028] Figure 6 Figure 3 is a schematic diagram of the deformation behavior of the heat-sensitive boss at different temperature stages of the present application.

[0029] Figure 1 is a schematic diagram of the cooperation of the heat-sensitive exhaust boss pad and the photovoltaic module laminated structure of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can be a mechanical connection or an electrical connection; they can be a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] The following is in conjunction with the appendix Figures 1-6 The specific embodiments of the present invention will be described in detail below.

[0034] Example 1:

[0035] This embodiment provides a thermally sensitive venting boss pad 3 for photovoltaic module lamination process, and its usage method in the lamination process. Figure 1 The overall structural diagram shown and Figure 2 The top view diagram shows that the main body of the thermal venting boss pad 3 is a flexible sheet structure, mainly composed of a flexible base layer 31 and a thermal boss array 32 disposed on its surface. In this embodiment, the flexible base layer 31 is made of high-temperature resistant glass fiber reinforced silicone rubber mesh, with a thickness of approximately 0.5 mm to 1.0 mm. The base layer is regularly distributed with honeycomb-shaped (hexagonal) flow-guiding holes 311, with a pore size of approximately 2 mm to 5 mm and an open area ratio controlled between 40% and 70%. These flow-guiding holes 311 ensure the air permeability of the pad in the vertical direction and provide space for the subsequent collapse and flow of the boss material at high temperatures. At the four corners of the pad 3, cross-shaped positioning holes or positioning marks 33 are provided for quick and accurate alignment with the corners of the photovoltaic module during lamination.

[0036] The core of this embodiment lies in the design of the thermal boss array 32. The bosses are frustoconical in shape and are integrally formed at the connection points of the mesh skeleton of the flexible substrate layer 31. Combined with... Figure 3 The partial cross-sectional view shown illustrates a significant height gradient distribution of the thermal boss array 32 on the macroscopic plane. Taking the pad adapted for the 182-type large-size module as an example, the central boss 321, located in the geometric center region, has the highest height (e.g., a total height of approximately 4.5 mm), while the edge boss 323, located at the outermost periphery, has the lowest height (e.g., a total height of approximately 2.8 mm). The height of the intermediate boss 322, located between the two, transitions smoothly. This gradient design, with a high center and low edges, aims to prioritize supporting the central region of the module during the initial vacuuming process, preventing premature sealing of the edges and subsequent internal air trapping.

[0037] The boss is made of a high polymer material with specific thermal sensitivity. In this embodiment, a specially made thermoplastic elastomer (TPE) is selected. The storage modulus of this material has a significant difference with temperature change: in the low temperature range from room temperature to 80°C (corresponding to the vacuum lamination stage), the Shore A hardness is greater than 60, showing a rigid state with sufficient bearing capacity; when the temperature exceeds 120°C into the high temperature range (corresponding to the lamination curing stage), the material softens rapidly, and the storage modulus decreases to less than 1 / 10 of the low temperature state, showing a viscous flexible state that is easily deformed and flows.

[0038] Method of use and working principle:

[0039] The following will be combined Figures 4 to 6 to explain in detail the process and working principle of using the above-mentioned heat-sensitive exhaust boss pad 3 for photovoltaic module lamination.

[0040] Step S1: Laying preparation.

[0041] As shown in Figure 4 , first complete the laying of the photovoltaic module stack structure 2 on the lower plate 12 of the laminator (the stack structure usually includes from bottom to top: glass substrate 21, lower adhesive film layer 22, cell piece 23, upper adhesive film layer 22 and back plate 24). Then, the heat-sensitive exhaust boss pad 3 of this embodiment is covered on the uppermost of the photovoltaic module stack structure 2 (i.e. the surface of the back plate 24), and is aligned by using the positioning hole or positioning mark 33. At this time, the upper pressing plate 11 of the laminator (usually a flexible silicone rubber plate assembly) is located above the heat-sensitive exhaust boss pad 3.

[0042] Step S2: Low temperature vacuum exhaust stage.

[0043] The laminator 1 closes the upper cover and starts the vacuum pump for pumping, while the laminator lower plate 12 is kept at a lower process temperature (for example 70°C).

[0044] At this stage, the heat-sensitive exhaust boss pad 3 is in a low temperature environment, according to the deformation behavior diagram shown in Figure 6 , the heat-sensitive boss is in a "low temperature rigid state" shown by T1, maintaining an upright shape and a higher hardness.

[0045] As shown in Figure 5 , under the action of negative pressure, the laminator upper pressing plate 11 is pressed down. Since the boss array has Figure 3The higher center zone bosses 321 are the first to contact and push against the upper platen 11 of the laminator, while the lower edge zone bosses 323 are not yet fully contacted or have less contact force. Thus, a macroscopically "thicker in the middle and thinner at the edges" wedge-shaped exhaust space is formed between the heat-sensitive exhaust boss pad 3 and the photovoltaic module stack structure 2. The residual gas inside and on the surface of the stack is smoothly guided and exhausted from the center to the periphery along the gaps between the bosses (as shown by the arrows Figure 5 The center gas and bubble problems caused by premature edge sealing are effectively avoided.

[0046] Step S3: high-temperature and pressure curing stage.

[0047] After the vacuum is completed, the lower platen 12 of the laminator begins to rapidly heat to a high-temperature process temperature (for example, 145°C), while the upper chamber of the laminator is filled with atmospheric pressure or positive pressure to apply pressure to the module.

[0048] With heat transfer, the temperature of the heat-sensitive exhaust boss pad 3 rapidly rises and exceeds the material softening point (about 120°C). According to the Figure 6 As shown, the heat-sensitive boss first undergoes a "medium-temperature softening state" shown by T2, and begins to deform; then it quickly changes to a "high-temperature collapsed state" shown by T3.

[0049] At this stage, the boss material that has lost rigidity collapses and flows under the strong pressure of the upper platen 11 of the laminator, and is pressed into the flow guide holes 311 of the flexible base layer 31. Finally, the entire heat-sensitive exhaust boss pad 3 changes from the initial uneven state to a flexible buffer layer with uniform thickness and smooth surface, which is tightly attached to the surface of the photovoltaic module stack structure 2. This process eliminates hard contact points, ensures that pressure is uniformly and gently transmitted to the surface of the fragile cell 23, significantly reduces the risk of hidden cracks, and achieves high-quality laminating and curing.

[0050] After the lamination is completed, the heat-sensitive exhaust boss pad 3 is integrally peeled off from the surface of the module after cooling and setting. The boss pad of the present embodiment has undergone irreversible deformation at the high-temperature stage, and is suitable for use as a one-time process auxiliary material.

[0051] Example Two:

[0052] This embodiment is another alternative structure form of Example One, which aims to provide a composite structure pad with higher mechanical strength and dimensional accuracy, especially suitable for production lines with higher automation.

[0053] The difference between this embodiment and Example One is that a layer of high-temperature-resistant polyimide (PI) film with a thickness of about 0.05mm to 0.1mm is added as an auxiliary reinforcing layer (not shown separately in the figure) between the flexible base layer 31 and the heat-sensitive boss array 32.

[0054] In the specific manufacturing process, the glass fiber reinforced silicone rubber mesh (base layer 31) is first laminated with the PI film, and then coaxial punching is performed on the PI film corresponding to the position of the base hole. Subsequently, the combined base is placed in the mold, and the hot-sensitive TPE material is injected onto the surface of the base through the injection molding process to form the hot-sensitive boss array 32. In this structure, the molten TPE material passes through the hole of the PI film and is tightly combined with the silicone rubber mesh base to form a physical riveting. The core role of introducing the PI film layer is to greatly improve the in-plane tensile strength and stiffness of the pad by using the excellent modulus of the PI material, preventing the base from stretching and deforming due to its own weight or traction force during the automatic mechanical arm grabbing, transporting and laying process, thereby ensuring the positioning accuracy of the boss array and the photovoltaic module.

[0055] The heat-sensitive collapse principle and one-time use logic in the lamination process are exactly the same as those of Embodiment I.

[0056] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A heat sensitive vent boss pad (3) for a photovoltaic module lamination process, characterized in that, The boss pad comprises a flexible base layer (31) and a heat-sensitive boss array (32) arranged on the surface of the flexible base layer (31); wherein a plurality of hole structures (311) for guiding and exhausting air are arranged on the flexible base layer (31); the heat-sensitive boss array (32) comprises a plurality of bosses distributed along the plane of the base layer, the bosses have a height distribution gradually decreasing from the central region to the peripheral region in the plane; the bosses are made of a material having temperature-dependent mechanical properties, the storage modulus of the material decreases significantly with the increase of temperature, so that the bosses maintain supporting strength at low temperature stage, soften and collapse at medium temperature stage, and conform to the interface at high temperature stage.

2. The heat sensitive exhaust boss gasket of claim 1 wherein, The flexible base layer (31) is in a grid or honeycomb structure, and the hole structure (311) is a regularly arranged polygonal hole.

3. The heat sensitive exhaust boss gasket of claim 1 wherein, The bosses in the heat-sensitive boss array (32) are divided into central region bosses (321), intermediate region bosses (322) and edge region bosses (323), wherein the height of the central region boss (321) is greater than that of the intermediate region boss (322), and the height of the intermediate region boss (322) is greater than that of the edge region boss (323).

4. The heat sensitive exhaust boss gasket of claim 1 wherein, The bosses are in a dome, cone or arc surface structure, and are integrally formed on the flexible base layer (31) by injection molding, molding or pouring.

5. The heat sensitive exhaust boss gasket of claim 1 wherein, The bosses are made of thermoplastic elastomer, phase change silicone or polymer material with a storage modulus that decreases with the increase of temperature.

6. The heat sensitive exhaust boss gasket of claim 1 wherein, The outer edge of the flexible base layer (31) is provided with a frame reinforcement area for realizing edge pressure relief and peripheral gas discharge during lamination.

7. The heat sensitive exhaust boss gasket of claim 1 wherein, The boss pad (3) is provided with positioning holes, positioning grooves or positioning marks (33) at the four corners for assembly and positioning with the lamination tool or glass plate.

8. The heat sensitive exhaust boss gasket of claim 1 wherein, The flexible base layer (31) and the heat-sensitive boss array (32) are integrally formed.

9. The heat sensitive exhaust boss gasket of claim 1 wherein, The boss pad (3) is arranged on the upper surface of the photovoltaic module stack structure to form an exhaust channel and realize uniform pressure fitting during lamination.

10. The heat sensitive exhaust boss gasket of any one of claims 1 to 9, wherein, At least one of an auxiliary support layer, a thermal insulation layer or a reinforcing layer can be arranged between the flexible base layer (31) and the heat-sensitive boss array (32).

11. A method of laminating a photovoltaic module using the heat sensitive exhaust tab gasket of any of claims 1 to 10, characterized in that, The method comprises the following steps: step S1: covering the heat-sensitive exhaust boss pad on the upper surface of the photovoltaic module stack structure, and using the height gradient of the boss array to form an exhaust channel that guides from the center to the edge at the stack interface; step S2: in the low-temperature vacuum extraction stage, keeping the lamination temperature below the softening temperature threshold of the boss material, using the rigid support of the boss to maintain the opening of the exhaust channel and guide the gas exhaust; step S3: in the high-temperature pressurization stage, the lamination temperature is increased to be higher than the softening temperature threshold, so that the boss softens and collapses into the hole structure of the flexible base layer, forming a flat buffer layer to compact and solidify the photovoltaic module.

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