Forming device for low-shrinkage photovoltaic adhesive film

Abstract

The invention discloses a forming device for a low-shrinkage photovoltaic adhesive film, which comprises a rack for bearing each component; the conveying assembly is used for bearing and conveying the adhesive film; the destressing assembly is arranged on the path of the conveying assembly, so that the conveying assembly penetrates through the destressing assembly, and a gap is reserved between the destressing assembly and the conveying assembly; the lifting assembly is arranged on the base under the rack, and a lifting part is connected with the rack; the moving assembly is arranged on the base and matched with a base rack below the base to drive the base to linearly move; and the cooling assembly is used for cooling the adhesive film conveyed by the conveying assembly. According to the invention, the conveyer belt is naturally cooled to the annealing section, then passes through the destressing assembly along with the conveyer belt to remove the internal stress of the adhesive film, then is slowly cooled to the temperature slightly higher than the melting point along with the conveyer belt, and then is cooled by the cold roller along with the traction of the conveyer belt. The shrinkage rate of the adhesive film can be greatly reduced, the shrinkage rate can be well controlled, and even an adhesive film product with the shrinkage rate being zero can be produced.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic encapsulation adhesive films, and in particular to a molding device for low-shrinkage photovoltaic adhesive films. Background Art

[0002] Photovoltaic adhesive film is usually used for encapsulation between solar cell silicon wafers and glass and backplanes, playing a role in bonding the glass and cell sheets of the battery module. During the hot pressing process of solar cells, EVA encapsulation adhesive film is prone to shrinkage. When the shrinkage rate is large, the shrinkage stress generated during the lamination process can easily cause the backplane to deform, and even cause the battery silicon wafer or glass panel to crack, resulting in the scrapping of the module. Therefore, the shrinkage rate is a relatively important control indicator for photovoltaic adhesive films.

[0003] At present, the shrinkage rate of the film is mainly controlled by using a heating tube or an infrared lamp to bake at the film outlet. However, as the production line speed increases, the lamp power often needs to be set very high. Since the temperature of the photovoltaic film is the highest at the extrusion die head after being melted and plasticized by the extrusion equipment, and the baking of the lamp causes the film temperature here to rise sharply, it is easy for the additives in the film formula to precipitate, thus affecting the quality of the film. Excessively high film temperature also requires high cooling in the subsequent process, which can easily cause problems such as unclear patterns and poor flatness of the film. And because the lamp is set at the film outlet, very close to the mold, long-term high-temperature baking will also cause irreversible damage to the mold. The higher the line speed of the production line, the more problems such as the above will occur. How to solve the shrinkage rate and flatness of the film in the process has become one of the key reasons for limiting the speed of the production line.

[0004] The purpose of this device is to provide a molding device that can effectively solve the shrinkage and flatness problems existing in the production of molded adhesive films, thereby obtaining a photovoltaic adhesive film with better flatness. Summary of the invention

[0005] In order to solve the above technical problems, a low shrinkage photovoltaic film molding device is provided.

[0006] To achieve the above-mentioned purpose, the present invention is configured in a preferred embodiment to include: a frame for carrying various components; a conveying component for carrying and transporting the adhesive film; a stress relief component arranged on the path of the conveying component so that the conveying component passes through the stress relief component, and a distance is left between the stress relief component and the conveying component; a lifting component arranged on a base directly below the frame, and the lifting part is connected to the frame; a moving component arranged on the base, cooperating with the rack of the base below the base to drive the base to move linearly; a cooling component for cooling the adhesive film conveyed by the conveying component.

[0007] In a preferred embodiment of the present invention, the stress relief assembly includes a heat release body parallel to the upper and lower sides of the conveyor belt, a box body is located outside the heat release body, and an area for the conveyor belt to pass through is reserved between the upper and lower boxes.

[0008] In a preferred embodiment, the present invention can be further configured as follows: the heat radiating body is a plurality of groups of equidistantly arranged lamp tubes, the lamp tubes are clamped in a V-shaped lamp tube cover, the lamp tube cover is fixed on a support frame, the support frame is mounted on a movable plate through an adjusting rod, and the height and horizontal displacement of the support frame are adjusted by the adjusting rod.

[0009] In a preferred embodiment of the present invention, the outer wall of the box body is provided with a movable plate connected with a quick unlocking lock, and the inner wall surface of the box body is paved with a heat-insulating reflective layer.

[0010] In a preferred embodiment, the present invention can be further configured as follows: the conveying assembly includes a conveyor belt, which passes through multiple groups of guide rollers and cold roller one, cold roller two, and cold roller three in sequence. The support of cold roller one is set on a slide rail, and the gap with cold roller two can be adjusted by a telescopic cylinder. An adjusting rod is set on the support of guide roller one to adjust the tension of the conveyor belt.

[0011] In a preferred embodiment, the present invention can be further configured as follows: the outer wall of the cold roller one is coated with a heat dissipation layer, the surface of the cold roller two is provided with a texture, and the temperatures of the cold roller one, the cold roller two, and the cold roller three are respectively higher than the former.

[0012] In a preferred embodiment of the present invention, the cooling assembly can be further configured as follows: the cooling assembly includes cold roller four, cold roller five, cold roller six, cold roller seven, and cold roller eight, and the above-mentioned multiple groups of cold rollers are arranged in a staggered manner in sequence.

[0013] In a preferred embodiment, the present invention can be further configured as follows: both ends of the cold rollers one to eight are provided with a water inlet A and a water outlet B, and at least two groups of non-interconnected spiral flow channels are provided inside the roller body, and each group of flow channels is respectively connected to the water inlet A at both ends of the cold roller.

[0014] In a preferred embodiment, the present invention can be further configured as follows: the moving component includes a dual-axis drive motor, the dual-axis drive motor is fixed on the base, and the two shafts are sleeved with traveling gears, the other end of the shaft is passed through the bearing seats on both sides of the base, and the traveling gears are meshed with the racks on the base.

[0015] Beneficial effect: A molding device for a low-shrinkage photovoltaic film of the present invention first naturally cools down to an annealing zone on a conveyor belt, then passes through a stress relief component along the conveyor belt to remove the internal stress of the film, then slowly cools down to a temperature slightly higher than the melting point along the conveyor belt, and then passes through a cold roller for cooling while being pulled by the conveyor belt. This calendering molding method that removes stress through a stress relief oven can greatly reduce the shrinkage of the film, can well control the shrinkage, and can even produce a film product with zero shrinkage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 It is a cross-sectional view of the present invention.

[0019] Figure 3 It is a schematic diagram of the stress relief component of the present invention.

[0020] Figure 4 It is a partial schematic diagram of the stress relief component of the present invention.

[0021] Figure 5 It is a schematic diagram of the mobile component of the present invention.

[0022] Figure 6 It is a schematic diagram of the internal flow channel of the cold roller of the present invention.

[0023] In the figure, 1 is a frame; 2 is a tensioning assembly; 3 is a stress relief assembly; 4 is a distance adjustment assembly; 5 is a conveying assembly; 6 is a cooling assembly; 7 is a transition wheel; 8 is a deviation correction assembly; 9 is a moving assembly; 12 is a base; 13 is a lifting assembly; 301 is an adjustment rod; 303 is a lamp cover; 304 is a quick-release lock; 306 is a support frame; 3013 is a movable plate; 501 is guide roller 1; 502 is auxiliary roller; 503 is conveyor belt; 504 is cold roller 1; 505 is guide roller 2; 506 is cold roller 2; 507 is cold roller 3; 508 is guide roller 3; 509 is guide roller 4; 601 is cold roller four; 603 is cold roller five; 604 is cold roller six; 605 is cold roller seven; 606 is cold roller eight; 903 is the travel gear; 905 is the rack. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] like Figure 1-6 As shown, a molding device for low shrinkage photovoltaic film includes: a frame 1 for carrying various components; a conveying component 5 for carrying and transporting the film; a stress relief component 3, arranged on the path of the conveying component, so that the conveying component passes through the stress relief component, and a distance is left between the stress relief component and the conveying component; a lifting component 13, arranged on a base directly below the frame, and the lifting part is connected to the frame; a moving component 9, arranged on the base, and cooperates with the rack of the base below the base to drive the base to move linearly; a cooling component 6, cools the film conveyed by the conveying component.

[0026] The stress relief component 3 includes a heat release body parallel to the upper and lower sides of the conveyor belt 503. The outer part of the heat release body is covered with a box. An area for the conveyor belt 503 to pass through is reserved between the upper and lower boxes. The conveyor belt passes through the middle of the stress relief component composed of the upper and lower ovens. Multiple groups of lamps are regularly distributed inside the stress relief component. The lamps are evenly distributed in a direction perpendicular to the moving direction of the conveyor belt and are symmetrically arranged at the upper and lower ends with the conveyor belt as the center. A space is formed by the lamps distributed inside the upper and lower boxes. When the lamps are turned on for heating, an annealing heating belt is formed. The conveyor belt passes through the annealing heating belt formed above. The stress relief component is arranged at the rear position of the middle part of the conveying horizontal section of the conveyor belt, and a certain space is reserved at the front and back. The distance from the front of the stress relief component to the mold part is set longer so that the stress relief component as a whole is far away from the die head. The distance from the end of the stress relief component to the calendering molding position is set shorter so that the film is slowly cooled in the air to a temperature suitable for calendering molding during the forward movement of the conveyor belt.

[0027] The heat-releasing body is a plurality of groups of lamp tubes arranged at equal distances, and the lamp tubes are clamped in a V-shaped lamp tube cover 303, and the lamp tube cover 303 is fixed on a support frame 306, and the support frame 306 is mounted on a movable plate 3013 through an adjusting rod 301, and the height and horizontal displacement of the support frame 306 are adjusted by the adjusting rod. The material of the lamp tube can be a far-infrared lamp tube, an ultraviolet lamp tube or a carbon fiber lamp tube, and the wavelength can be selected from medium-long wave, medium wave, medium-short wave or short wave band according to the absorption characteristics of the film. The lamp tube structure can be a single tube or a double twin tube in a facing type, and its main function is to anneal the film at a specific temperature range through the heat emitted by the double twin tubes, which has the advantage of eliminating the internal stress caused by the difference in casting and pulling speeds and the residual stress inside the molten film during extrusion of the die head, thereby improving the stability of the film. Thereby, the geometric dimensions and properties of the film are kept stable, the internal stress is released to weaken and reduce the size shrinkage of the film during hot melting, and the mechanical properties of the film are adjusted to meet the use requirements. The upper, lower, left and right positions of the lamp tube can be adjusted to set the distance from the lamp tube surface to the film. The distance from the lamp tube in the upper box to the film can be adjusted within the range of 5-15cm, and the distance from the lamp tube in the lower box to the film can be adjusted within the range of 10-20cm. The lower box is farther away from the film than the upper box, which can save energy on the one hand and ensure that the annealing of the film is completed with lower heat consumption and improve the shrinkage rate. On the other hand, it plays a role in preheating the conveyor belt. The temperature of the film is higher when it just comes out of the die head, which prevents the film from generating new internal stress due to excessive temperature difference at the moment of contact with the conveyor belt, thereby affecting the shrinkage rate of the film.

[0028] The outer wall of the box is provided with a movable plate connected with a quick-open lock 304, the inner wall of the box is paved with a thermal insulation reflective layer, and the inner walls of the upper and lower ovens are packaged with stainless steel reflective plates, which have the characteristics of low heat dissipation and thermal insulation, and can reflect the generated radiant heat. The reflected heat can still act on the absorption of the film, play a role in heat accumulation and reduce energy consumption. The box has a movable plate that can be opened quickly, which can facilitate observation of the internal situation of the box, and can also be used for film penetration and film guiding at the beginning of startup. At the same time, the height position of the lamp can be adjusted, and maintenance and replacement of the lamp are also faster.

[0029] The conveying assembly 5 includes a conveyor belt 503, which passes through multiple groups of guide rollers and cold roller 1 504, cold roller 2 506, and cold roller 3 507 in sequence. The support of cold roller 1 504 is set on the slide rail, and the gap with cold roller 2 506 can be adjusted by a telescopic cylinder. An adjusting rod is set on the support of guide roller 1 501 to adjust the tension of the conveyor belt. A plurality of auxiliary rollers arranged at intervals are set on the lower surface of the conveyor belt to support the conveyor belt and prevent the surface of the conveyor belt from collapsing over a long distance and causing the surface of the conveyor belt to be uneven, thereby affecting the flatness of the film. The conveyor belt may deviate during operation. To solve this problem, a correction device is added to the frame base. During the operation of the conveyor belt, the current position of the conveyor belt side is detected in real time through the through-beam sensor. When the side position changes, the sensor sends an adjustment signal corresponding to the direction of the current conveyor belt deviation. The PLC program controls the electric cylinder to make corresponding extension or retraction adjustment actions, so that the conveyor belt is adjusted to the opposite side and finally returns to the predetermined position.

[0030] The outer wall of cold roller 504 is coated with a heat dissipation layer, the surface of cold roller 506 is provided with a texture, and the temperatures of cold roller 504, cold roller 506 and cold roller 3 507 are respectively higher than the former. The cooling assembly 6 includes cold roller 4, cold roller 5, cold roller 6, cold roller 7 and cold roller 8. The above-mentioned multiple groups of cold rollers are arranged in a staggered manner in sequence. Both ends of cold rollers 1 to 8 are provided with water inlet A and water outlet B. At least two groups of non-interconnected spiral flow channels are provided inside the roller body, and each group of flow channels is respectively connected to the water inlet A at both ends of the cold roller. The film is formed between cold roller 1 504 and cold roller 2 506. In order to achieve better embossing effect, cold roller 1 504 adopts the form of surface coating with thermal conductive silicone or the form of a thin steel roller to ensure good heat dissipation performance. While realizing the cooling and shaping of the photovoltaic film, the thickness of the film can be effectively controlled to ensure that the thickness of the film is uniform. The surface of cold roller 2 is engraved with a pattern structure, which is used for pattern forming on the surface of the film. At the same time, the pattern on the surface of cold roller 2 also increases the friction between the conveyor belt and the conveyor belt to prevent the conveyor belt from slipping. The gap between cold roller 1 and cold roller 2 is adjusted by the roller spacing adjustment telescopic cylinder set on the frame. In order to achieve a good embossing effect while taking into account the release of stress in the film, the temperature settings of cold roller 1, cold roller 2 and cold roller 3 are different. The temperature of cold roller 1 can be set 5-20° lower than the set temperature of cold roller 2, and the temperature setting of cold roller 3 is 0°-10° higher than that of cold roller 2. The internal circulation medium of cold roller 2 and cold roller 3 is water or oil, and the temperature is controlled by the externally connected mold temperature controller. The lower temperature of cold roller 1 has a cooling effect on the conveyor belt, thereby controlling the temperature rise of the conveyor belt within a controllable range. Due to the width of the film, the temperature of each part of the roller surface must be balanced, and the temperature difference between the left, middle and right parts of the roller surface must be less than 2° to avoid shrinkage of the two sides of the film due to excessive temperature difference between the left and right roller surfaces, causing defects such as wrinkles and unevenness. There are currently three main ways for cooling water to flow inside the roller. Among them, the single-inlet and single-outlet form with water inlet on one side and water return on the opposite side. Due to the long length of the cold roller, there will be a temperature gradient difference when the cold water reaches the other side through one side of the roller, which is not conducive to the temperature balance requirement in the film casting production. There will be a dead corner of water flow in the middle part of the single-side water inlet and single-side water return, causing temperature imbalance. The double-inlet and double-outlet form with water inlet on one side and water return on the opposite side is adopted. In this way, the temperature gradient differences brought about in the length direction of the roller surface can offset each other, and the consistency of the roller surface temperature can be ensured. After the photovoltaic film leaves the conveyor belt, it bypasses cold rollers four to eight in turn to further cool the film. In this process, the surface temperature of the film is lower than the melting point, but the inside still has a certain temperature. Through full contact with the roller surface of each cold roller for heat exchange, the film is finally shaped, and the internal stress of the film caused by roller cooling is further released, thereby ensuring the final dimensional stability of the film shaping, which is very helpful for the shrinkage rate and flatness of the film.

[0031] The moving assembly 9 includes a dual-axis driving motor, which is fixed on the base 12, and the two shafts are sleeved with walking gears 903, and the other end of the shaft is connected to the bearing seats on both sides of the base. The walking gear 903 is meshed with the rack 905 on the base. When speeding up and slowing down according to the needs of the production line speed during the production process, the moving device can be started, and the driving motor installed on the molding device frame drives the walking gear connected to the transmission shaft to rotate, and the molding device frame indirectly connected to the walking gear is driven to do linear motion under the meshing of the gear pair, thereby driving the movement of the entire molding device. Finally, the motor power output is converted into the mechanical action of the entire molding device through the transmission of the gear rack, and it moves forward or backward along the film outlet direction of the production line, thereby adjusting the front and rear positions of the molding device in the film outlet direction of the production line within a range suitable for the current line speed, so that the molding device maintains a certain distance from the die head, and the lifting device is started at the same time. The rise and fall of the molding device are adjusted under the action of the lifting device, so as to adjust the height from the conveyor belt surface to the mold within a suitable range.

[0032] Working principle: After the film is melted and plasticized by the extruder, it is extruded from the forming flat die head, spread flat on the conveyor belt and moved forward with the traction of the conveyor belt. It is transported forward with the operation of the conveyor belt. In the transition section of the conveyance, the film is exposed to the air and naturally cooled down with the ambient temperature. When it reaches the stress relief component, it basically reaches the appropriate annealing temperature range. The film continues to be transported forward with the conveyor belt into the stress relief component, and in the annealing oven formed by the upper and lower ovens of the stress relief component, the molecular orientation inside the film is changed by the radiation wave of the lamp tube, thereby removing the excess internal stress. The stress relief annealing is completed in this movement process. The radiation density of the lamp tube can be adjusted at any time according to the line speed, film type, gram weight, etc. to meet the needs of film annealing and stress relief. After annealing, the film is sent out from the outlet of the stress relief component and enters the slow cooling transition section. During this movement, the film is further slowly cooled naturally in the air and continues to move forward with the operation of the conveyor belt until it reaches the film calendering area formed between cold roller one and cold roller two. During the entire horizontal conveying process, the conveyor belt movement speed matches the discharge speed of the die head, and the film is naturally cooled in the air. Therefore, the film is not affected by external forces, and the internal stress is removed by the stress relief component without generating new stress. When it reaches the calendering area, the temperature of the film is just in the temperature range suitable for calendering, and then the film forms a specific surface pattern under the calendering action of cold rollers one and two.

[0033] When passing through the gap between cold roller 1 and cold roller 2, the roller surface is cooled by the cooling medium inside cold roller 1 and cold roller 2. At the same time, cold roller 1 and cold roller 2 are attached together under the action of the roller gap adjustment device, and a certain pressure is formed. Under the pressure between the two rollers, the film surface forms a pattern opposite to the conveyor belt and cold roller 2. Due to the low temperature of the film during the calendering process and the cooling effect of the cooling medium, the temperature of the surface of cold roller 1 and cold roller 2 can be maintained in a dynamic stable state, which is not easy to affect the stress inside the film. At the same time, due to the good surface straightness of cold roller 1 and cold roller 2, and the roller gap adjustment device set between cold roller 1 and cold roller 2 on the left and right sides, the precise action of the electric cylinder and the precise measurement of the distance sensor can ensure that the roller gaps on both sides are consistent, thereby ensuring that the pressure on each part of the film in the wide direction is consistent, so that the depth of the embossed pattern can be accurately controlled to ensure the roughness requirements of the film embossing.

[0034] After passing through two rollers, the film continues to move forward with the conveyor belt. When it reaches the surface of cold roller three, the film is further cooled. At this time, the temperature of the film is only slightly higher than the roller temperature. The temperature of the film is close to that of cold roller three (i.e., the conveyor belt), and it is easy to peel off from the conveyor belt. After leaving the conveyor belt, it bypasses the transition roller and enters the five-roll cooling device for final cooling and shaping. The film passes through cold roller four to cold roller eight in sequence. The bypassing method is shown in the figure. Driven by the motor, the film rotates. During the traction process of each cold roller, the film fits with the roller surface of each cold roller. After the heat exchange cooling process with each cold roller, the inside of the film is cooled for final cooling and shaping, and the residual temperature and stress inside are further released to form a photovoltaic film with stable final dimensions. Then the film continues to move forward, and subsequently enters the thickness measurement, cooling and winding processes to complete the packaging of the film.

[0035] It should be noted that, in this document, relational terms such as first and second, etc. are merely used to distinguish one entity from another entity, but do not necessarily require or imply the existence of any such actual relationship or order between these entities.

[0036] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention belong to the protection scope of the present invention.

Claims

1. A low shrinkage photovoltaic film forming device, characterized in that: include: A frame (1) for carrying various components; A conveying component (5) for carrying and transporting the film; A stress relief component (3) is arranged on the path of the conveying component, so that the conveying component passes through the stress relief component, and a distance is left between the stress relief component and the conveying component; A lifting assembly (13) is arranged on a base directly below the frame, and a lifting part is connected to the frame; A moving assembly (9) is disposed on the base and cooperates with a rack on a base below the base to drive the base to move linearly; The cooling component (6) cools the adhesive film conveyed by the conveying component.

2. The low shrinkage photovoltaic film forming device according to claim 1, characterized in that: The stress relief assembly (3) comprises a heat-radiating body parallel to the upper and lower sides of the conveyor belt (503); a box body is disposed outside the heat-radiating body, and an area is left between the upper and lower boxes for the conveyor belt (503) to pass through.

3. The low shrinkage photovoltaic film forming device according to claim 2, characterized in that: The heat radiating body is a plurality of groups of lamp tubes arranged at equal distances, the lamp tubes are clamped in a V-shaped lamp tube cover (303), the lamp tube cover (303) is fixed on a support frame (306), the support frame (306) is mounted on a movable plate (3013) via an adjustment rod (301), and the height and horizontal displacement of the support frame (306) are adjusted via the adjustment rod.

4. A low shrinkage photovoltaic film forming device according to claim 2 or 3, characterized in that: The outer wall of the box is provided with a movable plate connected by a quick-release lock (304), and the inner wall of the box is paved with a heat-insulating reflective layer.

5. The low shrinkage photovoltaic film forming device according to claim 4, characterized in that: The conveying assembly (5) comprises a conveyor belt (503), wherein the conveyor belt (503) passes through a plurality of guide rollers and cold roller one (504), cold roller two (506), and cold roller three (507) in sequence. The support of cold roller one (504) is arranged on a slide rail, and the gap between the cold roller one (504) and cold roller two (506) can be adjusted by a telescopic cylinder. An adjusting rod is arranged on the support of guide roller one (501) to adjust the tension of the conveyor belt.

6. The low shrinkage photovoltaic film forming device according to claim 5, characterized in that: The outer wall of the cold roller one (504) is coated with a heat dissipation layer, the surface of the cold roller two (506) is provided with a texture, and the temperatures of the cold roller one (504), the cold roller two (506), and the cold roller three (507) are respectively higher than the former.

7. The low shrinkage photovoltaic film forming device according to claim 6, characterized in that: The cooling assembly (6) comprises a fourth cold roller, a fifth cold roller, a sixth cold roller, a seventh cold roller and an eighth cold roller, wherein the plurality of groups of cold rollers are arranged in a staggered manner in order.

8. The low shrinkage photovoltaic film forming device according to claim 7, characterized in that: Both ends of the cold rollers 1 to 8 are provided with a water inlet A and a water outlet B, and at least two groups of non-interconnected spiral flow channels are provided inside the roller body, and each group of flow channels is respectively connected to the water inlet A at both ends of the cold roller.

9. The low shrinkage photovoltaic film forming device according to claim 8, characterized in that: The moving assembly (9) comprises a dual-axis driving motor, which is fixed on the base (12), and the two shafts are sleeved with travel gears (903), the other ends of the shafts are inserted into bearing seats on both sides of the base, and the travel gears (903) are meshed with racks (905) on the base.

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