A high-temperature polypropylene film capacitor and its preparation method

Abstract

The present invention discloses a high-temperature polypropylene film capacitor and a preparation method thereof, specifically relating to the technical field of capacitor production. The capacitor includes a capacitor body, and the capacitor body includes a capacitor inner core. Metal conductive layers are formed at both ends of the capacitor inner core through gold spraying by a gold spraying machine. The capacitor inner core is wound from an inner core base material, and the inner core base material includes a film dielectric. A metal electrode layer is formed on the film dielectric through evaporation coating. The film dielectric is prepared by adding an antioxidant and a high-temperature heat stabilizer to polypropylene plastic particles. When the high-temperature polypropylene film capacitor produced by the present invention is subjected to gold spraying, the wrapping strip can closely adhere to the outer wall of the capacitor inner core, and can generate adaptive deformation according to the specific shape differences of the outer wall of the capacitor inner core, thereby ensuring that the side wall of the capacitor inner core can be fully protected during gold spraying, without causing forced extrusion on the capacitor inner core, and improving the product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitor production, and more specifically, to a high-temperature polypropylene film capacitor and a preparation method thereof. Background Art

[0002] A film capacitor is a capacitor that uses a polymer film as a dielectric and is widely used in various electronic devices. They are known for their high efficiency, low loss, and good frequency characteristics. Usually, polymer films such as polypropylene (PP), polyester (PET), polystyrene (PS), or polyethylene naphthalate (PEN) are used. These materials have high insulation resistance, low dielectric loss, and good self-healing properties. Metal is deposited on the dielectric substrate by vacuum evaporation; the whole capacitor is formed by winding two or more metallized films and plain films to form the capacitor core, and then gold is sprayed on both ends of the core to form a metal layer for easy welding of leads, and finally packaged to obtain the capacitor product.

[0003] With the rapid development of the electronic information industry and the power industry, higher requirements are put forward for indicators such as the temperature resistance and reliability of film capacitors. Therefore, the production control of capacitors is becoming more and more strict. Among them, the gold spraying process of capacitors mainly arranges the capacitor cores closely on the installation tray, aligns the gold spraying nozzle with the installation tray, and controls the slow relative movement between the nozzle and the core for gold spraying processing (heating the metal source material above its melting point until it evaporates, turning into a gas and spraying towards the end of the core, and depositing on the surface of the end of the core to form a metal conductive layer).

[0004] For film capacitors with a relatively small volume, their cores are also relatively small and can be arranged relatively closely during layout, and the gaps between the cores are relatively small. However, for capacitors with a relatively large volume, when arranging the cores for gold spraying, the gaps between the cores are relatively large, and it is easy for the material to enter the side wall of the core through the gap during gold spraying, affecting subsequent processing. Especially for the edge of the core end face, due to the change in the relative position and angle between the spray gun and each core during movement, the texture of the metal layer at the edge of the core end is uneven, and it is easy to form a "collapse" phenomenon (similar to a chamfer), affecting the quality of the capacitor.

[0005] In the prior art, to avoid the above problems, a form of covering mold is adopted to clamp and cover the periphery of the core end, only exposing the core end face area, thereby effectively restricting the gold spraying area, avoiding spraying on the side wall of the core, and also ensuring the gold spraying quality at the edge of the core end.

[0006] However, for some cylindrical film capacitors, their inner cores are mainly in a cylindrical shape formed by winding, with a uniform edge shape. A fixed circular arc-shaped covering mold can be simply used, which can almost completely fit the inner core. For some film capacitors, after the inner core is wound and formed, it also needs to be heat-pressed and shaped (flattened) to make the inner core flat, and semi-circular arc-shaped structures are formed on both sides of the end of the inner core. Due to the limitations of the materials of the film capacitor itself, the dimensional accuracy of the heat-pressing and shaping is not high, and the edge contour of the inner core after being flattened and formed is not precise. Therefore, when using the covering mold to cover and block the outer periphery of the end of the inner core, forced extrusion in some areas or gaps formed by non-contact in some areas will occur, thus affecting the limiting effect of the metallizing area. Especially in the areas where forced extrusion occurs, after the metallizing is completed and the covering mold is removed, stress will be released in this area, resulting in deformation, and then affecting the adhesion quality of the metallizing metal layer in this area and the processing efficiency. Summary of the Invention

[0007] A high-temperature polypropylene film capacitor and a preparation method thereof provided by the present invention aim to solve the problem that when the existing covering mold is adapted to the flattened inner core, forced extrusion in some areas or gaps formed by non-contact in some areas will occur when covering and blocking the outer periphery of the end of the inner core, thus affecting the limiting effect of the metallizing area and the metallizing quality in this area.

[0008] To achieve the above object, the present invention provides the following technical solution: A high-temperature polypropylene film capacitor preparation device includes a metallizing machine, in which a metallizing component and a support plate are arranged. The metallizing component includes a metallizing nozzle, and multiple groups of inner core fixing components are arranged on the support plate;

[0009] Each group of inner core fixing components includes two clamping frames. A clamping driver for controlling the two clamping frames to approach or separate from each other is also arranged on the support plate. A fixing space is arranged between the two clamping frames. A covering strip is arranged in the fixing space of each clamping frame. The corresponding sides of the fixing spaces of the two clamping frames are the open sides. The two ends of the covering strip are respectively connected to the two ends of the open side of the fixing space of the clamping frame, and both ends of the covering strip are connected to the clamping frame through elastic connectors.

[0010] In a preferred embodiment, an end pressing member is provided at one end corresponding to the opening side in the fixing space of the clamping frame, and a transfer pressing member is provided at the other end. Moreover, the transfer pressing member in one set of clamping frames corresponds to the position of the end pressing member in the corresponding other set of clamping frames. Both the end pressing member and the transfer pressing member are connected to the clamping frame through elastic connectors. A winding rotating shaft is provided at the position in the clamping frame corresponding to the transfer pressing member. The winding rotating shaft is rotatably installed in the clamping frame. One end of the covering strip is fixedly connected to the end pressing member, and the other end of the covering strip bypasses the transfer pressing member and is fixedly connected to the winding rotating shaft. A torsion elastic member is provided between the winding rotating shaft and the clamping frame.

[0011] In a preferred embodiment, a cylindrical support member is provided at the position of the transfer pressing member corresponding to the covering strip. The cylindrical support member is rotatably provided on the transfer pressing member. The covering strip forms an arc-shaped structure at the outer side position of the transfer pressing member. A wedge-shaped filling structure is provided at the position of the end pressing member corresponding to the arc-shaped structure.

[0012] In a preferred embodiment, a filling space is formed between the side of the covering strip facing away from the capacitor inner core and the clamping frame. The filling space is filled with filling balls. The particle diameter value of the filling balls is greater than the height difference between the top of the covering strip and the top of the capacitor inner core.

[0013] In a preferred embodiment, a vibrator is provided on the clamping frame. The vibrator is fixedly installed outside the clamping frame. A capacity regulator is further provided in the filling space. The capacity regulator is of a plug column structure. The capacity regulator is slidably inserted into the side wall of the clamping frame, and one end of the capacity regulator extends into the filling space.

[0014] In a preferred embodiment, the gold spraying assembly further includes a nozzle driver for driving the gold spraying nozzle to move. A tray driver is provided in the gold spraying machine. The tray is installed on the tray driver, and the tray driver is used to drive the tray to move. The moving direction of the tray is perpendicular to the moving direction of the gold spraying nozzle.

[0015] In a preferred embodiment, the clamping driver includes a bidirectional threaded screw rod. The bidirectional threaded screw rod is rotatably installed in the tray. The bottom of the clamping frame is fixedly connected with a slider structure. The slider structure is slidably arranged in the tray. The bidirectional threaded screw rod penetrates through the slider structures of each group of clamping frames. A set of threads is respectively provided at the positions of the bidirectional threaded screw rod corresponding to the two groups of clamping frames in each group of inner core fixing components, and the two corresponding threads have opposite helix directions. The slider structure is threadedly connected to the bidirectional threaded screw rod through the threads. A screw rod rotation driver is further provided on the tray, and the screw rod rotation driver is used to drive the bidirectional threaded screw rod to rotate.

[0016] In a preferred embodiment, the tray driver is a conveying structure. A loading port and an unloading port are respectively arranged at two ends of the spraying machine corresponding to the conveying structure. A quick-release structure for docking with the pallet is arranged on the conveying structure, and the pallet is detachably connected to the conveying structure through the quick-release structure.

[0017] A high-temperature polypropylene film capacitor includes a capacitor body. The capacitor body includes a capacitor inner core. Metal conductive layers are formed at both ends of the capacitor inner core by spraying gold with a spraying machine. The capacitor inner core is wound from an inner core base material. The inner core base material includes a film dielectric. A metal electrode layer is formed on the film dielectric by evaporation coating. The film dielectric is prepared by adding antioxidants and high-temperature heat stabilizers to polypropylene plastic particles.

[0018] A preparation method of a high-temperature polypropylene film capacitor includes the following steps:

[0019] Step 1: Film dielectric processing. Prepare polypropylene plastic particles, add antioxidants and high-temperature heat stabilizers, extrude and form after melting, and stretch to form a film dielectric;

[0020] Step 2: Film dielectric heat treatment. Heat the film dielectric obtained in Step 1 and perform annealing treatment;

[0021] Step 3: Inner core base material preparation. Wind and cut the film dielectric obtained in Step 2, and then evaporate and coat a metal electrode layer on the surface of the film dielectric through an evaporation coating device, and then cut it according to the required size to form an inner core base material;

[0022] Step 4: Inner core preparation. Wind two inner core base materials face to face to form a coil, and then perform hot pressing and shaping through a hot pressing device to form a capacitor inner core. After shaping, perform vacuum drying on the capacitor inner core;

[0023] Step 5: Spraying gold processing. Place the capacitor inner core in two corresponding clamping frames, control the two clamping frames to approach each other, so that the wrapping tape wraps the outer wall of the capacitor inner core and forms a fixation for the capacitor inner core. Then turn on the control of the spraying gold nozzle and control the movement of the spraying gold nozzle to perform spraying gold processing on the end surface of the capacitor inner core, so that a metal conductive layer is formed at the end of the capacitor inner core;

[0024] Step 6: Welding and encapsulation. Weld leads on the metal conductive layers at both ends of the capacitor inner core, and then place the capacitor inner core in an encapsulation shell for injection molding encapsulation to form a film capacitor product.

[0025] The beneficial effects of the present invention are as follows: When the high-temperature polypropylene film capacitor produced by the present invention is subjected to metallizing processing, after being clamped by two sets of clamping frames, the wrapping strip can closely adhere to the outer wall of the capacitor inner core, and can generate adaptive deformation according to the specific shape differences of the outer wall of the capacitor inner core. Furthermore, it can ensure that the side wall of the capacitor inner core can be fully protected during metallizing, and no forced extrusion will be exerted on the capacitor inner core, ensuring that a sufficiently thick and uniform metal conductive layer structure can also be formed at the edge of the end of the capacitor inner core, improving the product quality. Moreover, the film dielectric material of this embodiment selects high-purity polypropylene resin as the basic raw material, and additives such as antioxidants and high-temperature heat stabilizers are added according to specific performance requirements, which can effectively improve the performance of the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the external structure of the metallizing machine of the present invention.

[0027] Figure 2 It is a schematic diagram of the internal structure of the metallizing machine of the present invention.

[0028] Figure 3 It is a schematic diagram of the structure of the present invention using a conveying device as a pallet driver.

[0029] Figure 4 It is a schematic diagram of the structure of each group of inner core fixing components on the pallet of the present invention.

[0030] Figure 5 It is a schematic diagram when the capacitor inner core of the present invention is placed into the fixed space between two adjacent sets of clamping frames.

[0031] Figure 6 It is a state diagram when the wrapping strip and the capacitor inner core are fitted and wrapped after clamping in the present invention.

[0032] Figure 7 It is a state diagram when the metallizing nozzle of the present invention performs metallizing treatment on the capacitor inner core after wrapping.

[0033] Figure 8 It is a schematic diagram of the structure of the present invention after improving the inner core fixing component.

[0034] Figure 9 For the present invention Figure 8 Enlarged view of the structure of part A.

[0035] Figure 10 It is a longitudinal sectional view of the present invention after improving the inner core fixing component.

[0036] Figure 11 It is a state diagram when the capacitor inner core is taken out after metallizing in the present invention.

[0037] Figure 12This is a schematic diagram of the rebound state of the wrapping strip after removing the inner core of the capacitor in the present invention.

[0038] Figure 13 This is a schematic diagram of the structural composition of the high-temperature polypropylene film capacitor of the present invention.

[0039] Figure 14 This is a schematic diagram of the composition of the inner core substrate of the present invention.

[0040] Figure 15 This is a flowchart of the preparation method of the present invention.

[0041] The reference numerals are: 1. Metal spraying machine; 11. Tray driver; 12. Feeding port; 13. Discharging port; 2. Metal spraying assembly; 21. Metal spraying nozzle; 22. Nozzle driver; 3. Pallet; 31. Clamping driver; 311. Bidirectional threaded screw; 312. Screw rotation driver; 4. Inner core fixing assembly; 41. Clamping frame; 411. Slide block structure; 412. Filling space; 413. Vibrator; 414. Capacity regulator; 42. Wrapping strip; 43. Elastic connecting piece; 44. Winding rotating shaft; 45. Intermediate pressing and pasting piece; 451. Cylindrical support piece; 46. End pressing and pasting piece; 47. Filling ball; 5. Capacitor body; 51. Capacitor inner core; 511. Film dielectric; 512. Metal electrode layer; 52. Metal conductive layer. Detailed implementation manners

[0042] The following further describes the present application in detail with reference to the drawings. It is necessary to point out here that the following specific implementation manners are only used to further illustrate the present application and cannot be construed as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0043] Referring to the attached drawings of the specification Figures 1 to 12 A device for preparing a high-temperature polypropylene film capacitor includes a metal spraying machine 1. Inside the metal spraying machine 1, there are a metal spraying assembly 2 and a pallet 3. The metal spraying assembly 2 includes a metal spraying nozzle 21 and a nozzle driver 22. The nozzle driver 22 is used to drive the metal spraying nozzle 21 to move. Among them, the nozzle driver 22 can adopt a single driving device, such as a single linear motor, etc., or can be provided with a multi-directional driving device according to needs to improve the sufficiency of the metal spraying operation. Regarding the specific metal spraying operation of the metal spraying nozzle 21 and the technologies such as the movement driving of the metal spraying nozzle 21, they are all common schemes in the existing metal spraying process, and this embodiment will not elaborate too much.

[0044] Multiple groups of inner core fixing components 4 are arranged on the pallet 3. The inner core fixing components 4 are used to clamp the capacitor inner core 51. A pallet driver 11 is arranged in the spraying machine 1, and the pallet 3 is installed on the pallet driver 11. The pallet driver 11 is used to drive the pallet 3 to move (such as using devices such as linear motors and cylinders). Among them, when the nozzle driver 22 drives in a single direction, the driving direction of the pallet driver 11 for the pallet 3 needs to be perpendicular to the driving direction of the nozzle driver 22 for the spraying nozzle 21 to ensure sufficient spraying on multiple capacitor inner cores 51 installed on the same pallet 3. When the nozzle driver 22 drives in multiple directions and can ensure that the spraying nozzle 21 covers all areas of the pallet 3, the pallet driver 11 can also be not used. The pallet 3 and the pallet driver 11 can be connected through a detachable connection structure such as a clamping seat and bolts, so as to facilitate taking out the pallet 3 from the spraying machine 1 and loading and unloading multiple capacitor inner cores 51 at the same time.

[0045] Further, each group of inner core fixing components 4 includes two clamping frames 41. A clamping driver 31 for controlling the two clamping frames 41 to approach or move away from each other is also arranged on the pallet 3. A fixing space is arranged between the two clamping frames 41. A covering strip 42 is arranged in the fixing space of each clamping frame 41. The two ends of the covering strip 42 are connected to the edges of the covering space of the clamping frame 41. Specifically, referring to the attached Figure 5 description, the corresponding sides of the fixing spaces in the two clamping frames 41 are the open sides. The two ends of the covering strip 42 are respectively connected to the two ends of the open sides of the fixing spaces of the clamping frames 41, and the two ends of the covering strip 42 are both connected to the clamping frames 41 through elastic connectors 43.

[0046] During use, the capacitor inner core 51 is placed between two corresponding covering strips 42 in the two clamping frames 41. When fixing is required, the two clamping frames 41 are controlled to approach and dock with each other, so that the two covering strips 42 contact each other and form a closed covering, effectively wrapping the outer side wall of the capacitor inner core 51. The covering strip 42 can be made of a metal thin-walled strip or a plastic part, etc. In order to improve the service life, the covering strip 42 in this embodiment is preferably a metal strip. When the capacitor inner core 51 is placed in the fixing space in the clamping frame 41, the top height of the covering strip 42 is higher than the top height of the capacitor inner core 51 to ensure full coverage and protection of the capacitor inner core 51.

[0047] After the inner core fixing assembly 4 has completed the fixing of the capacitor inner core 51, the gold spraying can be carried out through the gold spraying nozzle 21, and the relative movement between the gold spraying nozzle 21 and the pallet 3 is controlled to fully spray gold on all the capacitor inner cores 51. Since the wrapping strip 42 in this embodiment has deformability, after the two clamping frames 41 are clamped, the wrapping strip 42 can closely adhere to the outer wall of the capacitor inner core 51 and generate adaptive deformation according to the specific shape differences of the outer wall of the capacitor inner core 51 (when the capacitor inner core 51 is wound, the number of winding turns is fixed, so the circumference of the formed cylinder is fixed. Although the shape changes after hot pressing and unknown deformations occur in some areas, its overall circumference remains almost unchanged. Therefore, the length of the wrapping strip 42 can also be fixedly set, making it more sufficient during actual fitting). At the same time, an elastic connecting piece 43 is provided between the end of the wrapping strip 42 and the clamping frame 41, and relative elastic force can also be generated at the butt joint of the two wrapping strips 42, so that the wrapping strip 42 in the end area can also closely adhere to the capacitor inner core 51 and generate adaptive changes, which can ensure that the side wall of the capacitor inner core 51 can be fully protected during gold spraying, without causing forced extrusion to the capacitor inner core 51, and thus the capacitor inner core 51 itself will not be deformed. At the same time, by means of the shielding of the wrapping strip 42 on the end edge of the capacitor inner core 51, it can be ensured that a thick and uniform metal conductive layer 52 structure can also be formed on the end edge of the capacitor inner core 51. And when the gold spraying is completed and the two clamping frames 41 are controlled to separate, the pressure of the wrapping strip 42 on the capacitor inner core 51 is removed, and the wrapping strip 42 will generate restorative deformation, and then will automatically separate from the edge of the capacitor inner core 51. And the capacitor inner core 51 itself is relatively thin, the attached metal material formed by gold spraying on its top is relatively less, and the adhesion is not high. Therefore, it will hardly affect the metal conductive layer 52 on the edge of the capacitor inner core 51 during separation, improving the product quality.

[0048] Refer to the attached drawings of the specification Figure 4 and Figure 7 As shown in FIGS. and

[0048] , the clamping driver 31 includes a bidirectional threaded screw 311. The bidirectional threaded screw 311 is rotatably installed in the pallet 3. The bottom of the clamping frame 41 is fixedly connected with a slider structure 411. The slider structure 411 is slidably arranged in the pallet 3. The bidirectional threaded screw 311 passes through the slider structures 411 of each clamping frame 41. A set of threads is respectively arranged at the positions of the bidirectional threaded screw 311 corresponding to the two clamping frames 41 in each inner core fixing assembly 4, and the rotation directions of the mutually corresponding two sets of threads are opposite. The slider structure 411 is threadedly connected with the bidirectional threaded screw 311 through the thread. A screw rotation driver 312 is further arranged on the pallet 3. The screw rotation driver 312 is used to drive the bidirectional threaded screw 311 to rotate, so as to control the corresponding two clamping frames 41 to approach or move away from each other.

[0049] It should be noted that the above is only one of the driving methods for the clamping frame 41 provided in this embodiment, and all other adapted driving methods can be applied in this embodiment. Regarding the screw rotation driver 312, an automated device such as a motor can be used to automatically control the double-threaded screw 311. Correspondingly, a power supply docking structure adapted to the pallet 3, such as a plug socket or a contact structure, can be provided on the pallet driver 11 to facilitate the disassembly of the pallet 3. At the same time, the screw rotation driver 312 can also adopt a manual control structure such as a knob to manually control the rotation of the double-threaded screw 311. Before the pallet 3 is loaded into the metallizing machine 1, the clamping frames 41 can be manually controlled to approach each other to clamp the capacitor core 51.

[0050] Among them, in order to improve production efficiency, the metallizing machine 1 can also be improved into a continuous processing device. For example, the conveying structure shown in the attached drawings of the specification (such as a chain conveying structure) can be used as the pallet driver 11 to control the movement of the pallet 3, and a loading port 12 and an unloading port 13 can be respectively provided on the metallizing machine 1 for loading and unloading. A quick-release structure such as a socket is provided between the pallet driver 11 and the pallet 3 to realize the movement control of the pallet 3 and also the production line conveying. It should be noted that a closing door structure needs to be provided at the loading port 12 and the unloading port 13 to ensure processing safety. Figure 2 In the above embodiment, the end of the wrapping strip 42 can be directly fixedly connected to the elastic connecting member 43. This solution is relatively simple and has a relatively low cost. However, the length of the wrapping strip 42 formed by this solution is fixed, the size of the capacitor core 51 that can be adapted is fixed, and the length of the wrapping strip 42 cannot change, and the actual fitting effect with the capacitor core 51 is relatively poor. Therefore, this embodiment also provides the following technical solution. Specifically, referring to the attached drawings of the specification

[0051] In the above embodiment, the end of the wrapping strip 42 can be directly fixedly connected to the elastic connecting member 43. This solution is relatively simple and has a relatively low cost. However, the length of the wrapping strip 42 formed by this solution is fixed, the size of the capacitor core 51 that can be adapted is fixed, and the length of the wrapping strip 42 cannot change, and the actual fitting effect with the capacitor core 51 is relatively poor. Therefore, this embodiment also provides the following technical solution. Specifically, referring to the attached drawings of the specification Figures 8 to 11, at one end corresponding to the opening side in the fixing space of the clamping frame 41, an end pressing member 46 is provided, and at the other end, a transfer pressing member 45 is provided. Moreover, the positions of the transfer pressing member 45 in one group of clamping frames 41 correspond to the positions of the end pressing members 46 in the corresponding other group of clamping frames 41. Both the end pressing member 46 and the transfer pressing member 45 are connected to the clamping frame 41 through elastic connectors 43 (the elastic connectors 43 can be rubber soft pads or spring structures, etc.). At the position in the clamping frame 41 corresponding to the transfer pressing member 45, a winding rotating shaft 44 is provided. The winding rotating shaft 44 is rotatably installed in the clamping frame 41. One end of the covering strip 42 is fixedly connected to the end pressing member 46, and the other end of the covering strip 42 bypasses the transfer pressing member 45 and is fixedly connected to the winding rotating shaft 44. A torsion elastic member is provided between the winding rotating shaft 44 and the clamping frame 41. This torsion elastic member is used to provide an elastic force for winding the covering strip 42 to the winding rotating shaft 44. The transfer pressing member 45 is arranged in a fitting manner with the covering strip 42. When the two groups of clamping frames 41 approach and contact each other, the corresponding end pressing members 46 and transfer pressing members 45 in each group of clamping frames 41 approach each other. And since one end of the covering strip 42 bypasses the transfer pressing member 45, therefore, the end pressing member 46 in the other group of clamping frames 41 corresponding to this transfer pressing member 45 is in contact with the part of the covering strip 42 that bypasses the transfer pressing member 45. Among them, since the covering strip 42 at the position where it bypasses the transfer pressing member 45 forms an arc-shaped structure, therefore, a wedge-shaped filling structure is provided at the position of the end pressing member 46 corresponding to this arc-shaped structure. Specifically, refer to the attached Figure 9 , to ensure that after the two groups of covering strips 42 are butted, a relatively closed structure can still be maintained.

[0052] During actual use, due to the winding elastic force of the winding rotating shaft 44 on the covering strip 42, one end of the covering strip 42 has a tensile elastic force. Furthermore, under the transfer support of the transfer pressing member 45, the effective length (the actual length in contact with the capacitor inner core 51) of the covering strip 42 in each group of clamping frames 41 can adaptively change, and thus can be adapted to more capacitor inner cores 51 (such as cylindrical capacitor inner cores 51 and other capacitor inner cores 51 with different sizes). At the same time, this tensile elastic force can enable the covering strip 42 to more effectively adhere to the surface of the capacitor inner core 51, forming a more effective coverage.

[0053] Especially after the gold spraying is completed and the capacitor inner core 51 is taken out, under the elastic force of the winding rotating shaft 44, the covering strip 42 will generate more deformations, and its top can generate bending changes with different curvatures. Refer to the attached Figure 12, so that the metal spraying structure formed on the top of the coated strip 42 is easier to fall off, and in order to protect the respective active areas of the transfer pressing member 45, the end pressing member 46 and the winding shaft 44, a thin plate can be set above them to shield and protect them.

[0054] A columnar support member 451 is provided at the position of the transfer pressing member 45 corresponding to the coating strip 42. For structures with limited space, the columnar support member 451 can be a fixed structure directly formed on the transfer pressing member 45. For situations with sufficient space, the columnar support member 451 can be rotatably set on the transfer pressing member 45, thereby reducing the friction loss between the coating strip 42 and the transfer pressing member 45.

[0055] Furthermore, a filling space 412 is formed between the side of the coating strip 42 facing away from the capacitor core 51 and the clamping frame 41, and the filling space 412 is filled with filling balls 47, and the particle diameter of the filling balls 47 is larger than the height difference from the top of the coating strip 42 to the top of the capacitor core 51, wherein the coating strip 42 can be selected from metal ball particles, or other spherical particles such as ceramic ball particles.

[0056] A vibrator 413 is provided on the clamping frame 41. The vibrator 413 is fixedly mounted on the outside of the clamping frame 41 and is used to vibrate the clamping frame 41. It should be noted that in addition to directly setting the vibrator 413 on the clamping frame 41, a group of devices for vibrating the clamping frame 41 can also be separately set, such as a vibration manipulator. The vibrator is installed on the manipulator, and the manipulator drives the vibrator to contact the clamping frame 41 to vibrate the clamping frame 41. However, for ease of operation, the present embodiment preferably sets the vibrator 413 on the clamping frame 41, and the vibrator 413 can be a vibration motor. Regarding the power supply of the vibrator 413, a small battery can be set on the support plate 3, or as mentioned above, a corresponding power supply and control circuit and the corresponding electrical connection docking structure can be set on the loading port 12 to power and control the vibrator 413.

[0057] After the clamping frame 41 clamps the capacitor core 51, the filling balls 47 are put into the filling space 412 and filled to the top area of the coating strip 42. The excess filling balls 47 are scraped off (the particle diameter of the filling balls 47 is larger than the height difference between the top of the coating strip 42 and the top of the capacitor core 51, so it is not easy to stay on the surface of the capacitor core 51). While putting in, the clamping frame 41 with the vibrator 413 vibrates, thereby making the filling balls 47 compact. At the same time, the granular filling balls 47 are on the coating strip 42. The outer wall forms a sufficient squeeze on the filling ball 47. Therefore, even if there is a slight depression on the side wall surface of the capacitor core 51, the pressure of the filling ball 47 can make the coating strip 42 produce adaptive deformation and fit the capacitor core 51 (mainly for the top area, to ensure that no gap is formed between the coating strip 42 and the top area of the capacitor core 51). Since no gap is formed, when gold is sprayed, no metal connection structure is formed between the coating strip 42 and the side wall of the capacitor core 51, which is easier to separate later.

[0058] It should be noted that due to the presence of the filling balls 47, the empty space between the coating strip 42 and the clamping frame 41 is filled. Therefore, the filling balls 47 on the top layer can receive the gold-sprayed material so that the gold-sprayed material will not fall into the space between the clamping frame 41 and the coating strip 42. Moreover, after the gold spraying is completed, before the two sets of clamping frames 41 are separated, the vibrator 413 can be controlled to vibrate again, thereby making the internal filling balls 47 move. On the one hand, the filling balls 47 forming the metal layer on the top can be relatively separated to break the metal layer in this area. On the other hand, the vibration of the filling balls 47 can also be transmitted to the contact area between the coating strip 42 and the top edge of the capacitor core 51, so that the edge of the metal layer in the area is broken, making it easier to separate from the coating strip 42.

[0059] For further information, please refer to the attached manual. Figure 10 and Figure 11 A capacity regulator 414 is also provided in the filling space 412. The capacity regulator 414 is used to adjust the volume of the filling space 412. Specifically, the capacity regulator 414 is a plug structure. The capacity regulator 414 is slidably inserted in the side wall of the clamping frame 41, and one end of the capacity regulator 414 extends into the filling space 412.

[0060] Before filling the filling ball 47, the capacity regulator 414 can be inserted into the filling space 412. When the gold spraying is completed and the capacitor core 51 needs to be removed, the vibrator 413 is controlled to vibrate first, and then the capacity regulator 414 is controlled to move out of the filling space 412. At this time, refer to the attached manual. Figure 11, as the internal space of the filling space 412 increases, the filling balls 47 will sink relatively, thereby increasing the movement amplitude of the filling balls 47. At the same time, the metal layer structures formed on the tops of the filling balls 47 and the top of the coating strip 42 will also be more fully separated due to the sinking of the filling balls 47, improving the separation effect between the metal conductive layer 52 at the top of the capacitor inner core 51 and the redundant metal layer structure, and further improving the product quality.

[0061] It should be noted that the above plug column structure is only one of the space control schemes provided in this embodiment. In addition, a structure similar to an airbag can also be used for control, as long as it can ensure the sinking of the filling balls 47.

[0062] It should be noted that for existing thin film capacitors, the mainly widely used ones are polyester film and polypropylene film capacitors. Although polyester material capacitors have a relatively high temperature coefficient, due to their large high-frequency losses, they are not suitable for use in high-frequency and high-current circuits. Conventional polypropylene film capacitors have good high-frequency characteristics and are suitable for use in high-frequency and high-current circuits. However, polypropylene film capacitors have a poor temperature tolerance and are not suitable for working in a relatively high ambient temperature. For example, for polypropylene capacitors used in such a high-temperature environment, as their working time increases, their internal temperature rises rapidly, resulting in a sharp decline in the stability of the capacitors and even causing the capacitors to fail, posing a serious safety hazard to electronic equipment and the power grid.

[0063] Therefore, on the premise of improving the quality of metal spraying, this embodiment also provides a high-temperature polypropylene film capacitor with better performance. Specifically, referring to the attached Figure 13 and Figure 14 , it includes a capacitor body 5. The capacitor body 5 includes a capacitor inner core 51. Metal conductive layers 52 are formed at both ends of the capacitor inner core 51 through metal spraying by a metal spraying machine 1. The capacitor inner core 51 is wound from an inner core base material. Among them, referring to the attached Figure 14 , the inner core base material includes a film dielectric 511. A metal electrode layer 512 is formed on the film dielectric 511 through evaporation coating. The film dielectric 511 is made of high-purity polypropylene plastic particles, added with an antioxidant and a high-temperature heat stabilizer, mixed and melted, and then extruded and stretched.

[0064] It should be noted that both the antioxidant and the high-temperature heat stabilizer are commonly used plastic additives. Therefore, the specific components are not elaborated in this embodiment.

[0065] In addition, to comprehensively improve the quality of the thin film capacitor, based on the above preparation device, this embodiment also provides a preparation method for a high-temperature polypropylene film capacitor. Referring to the attached Figure 15 , it includes the following steps:

[0066] Step 1: Processing of the thin-film dielectric 511. Prepare high-purity polypropylene plastic particles, add antioxidants and high-temperature heat stabilizers, melt them and then extrude and stretch to form the thin-film dielectric 511. Among them, use Borealis polypropylene 310 plastic particles (the traditional base material polypropylene plastic particle model is 303). Put the raw materials into the extruder, heat them to 200°C - 250°C to melt them, and through the rotation of the screw to push, extrude the molten polypropylene into sheets. Then, perform biaxial stretching on the extruded polypropylene sheets in the longitudinal and transverse directions to make the molecular chains orient along the stretching direction, improving the performance of the thin film.

[0067] Step 2: Heat treatment of the thin-film dielectric 511. Heat the thin-film dielectric 511 obtained in Step 1 to 120°C - 150°C and perform annealing treatment.

[0068] Step 3: Preparation of the inner core substrate. Wind up and cut the thin-film dielectric 511 obtained in Step 2, and then vapor-deposit a metal electrode layer 512 on the surface of the thin-film dielectric 511 through vapor-deposition equipment. Then, cut it according to the required size to form the inner core substrate.

[0069] Step 4: Preparation of the inner core. Wind two inner core substrates together face to face to form a coil, and then perform hot pressing and shaping through hot pressing equipment to form the capacitor inner core 51. After shaping, perform vacuum drying on the capacitor inner core 51. The drying temperature is 130°C and the drying duration is 4 hours.

[0070] Step 5: Gold spraying process. Place the capacitor inner core 51 in the corresponding two sets of clamping frames 41, control the two sets of clamping frames 41 to approach each other, so that the wrapping tape 42 wraps the outer wall of the capacitor inner core 51 and forms a fixation on the capacitor inner core 51. Then, turn on the control of the gold spraying nozzle 21 and control the movement of the gold spraying nozzle 21 to fully perform gold spraying on the end surface of the capacitor inner core 51, so that a metal conductive layer 52 is formed at the end of the capacitor inner core 51.

[0071] Step 6: Welding and encapsulation. Weld leads on the metal conductive layers 52 at both ends of the capacitor inner core 51 respectively, and then place the capacitor inner core 51 in the encapsulation shell for injection molding encapsulation to form a thin-film capacitor product. After the test is completed, it can be packaged.

[0072] Among them, the thin-film dielectric 511 material in this embodiment selects high-purity polypropylene resin as the base material, and additives such as antioxidants and high-temperature heat stabilizers are added according to specific performance requirements to improve the high-temperature resistance and processing characteristics of the polypropylene thin-film dielectric 511 material. The high-temperature polypropylene thin-film dielectric 511 used in this embodiment is not easily softened or decomposed in a high-temperature environment, ensuring the capacitance structure and electrical performance. Furthermore, the capacitance structure can have an extremely low dielectric loss in a high-temperature environment, effectively reducing energy loss and heat generation, having a high insulation resistance, effectively preventing leakage, and ensuring the safe operation of the capacitor in a high-temperature and high-voltage environment. At the same time, the capacitance stability is excellent, less affected by temperature, providing a stable capacitance value for the circuit. And because the thin-film dielectric 511 undergoes effective heat treatment during production, it has good mechanical properties, has a certain flexibility and tensile strength at high temperatures, and is not easily brittle.

[0073] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A device for preparing a high-temperature polypropylene film capacitor, comprising a gold spraying machine (1), wherein a gold spraying assembly (2) and a pallet (3) are arranged inside the gold spraying machine (1), and the gold spraying assembly (2) comprises a gold spraying nozzle (21), characterized in that: A plurality of inner core fixing components (4) are arranged on the pallet (3); Each group of the inner core fixing components (4) includes two clamping brackets (41). A clamping driver (31) for controlling the two clamping brackets (41) to approach or separate from each other is further arranged on the pallet (3). A fixing space is arranged between the two clamping brackets (41). A covering strip (42) is arranged in the fixing space of each group of the clamping brackets (41). The corresponding sides of the fixing spaces in the two clamping brackets (41) are open sides. Two ends of the covering strip (42) are respectively connected with two ends of the open side of the fixing space of the clamping bracket (41), and two ends of the covering strip (42) are both connected with the clamping bracket (41) through elastic connecting pieces (43); A filling space (412) is formed between the side of the covering strip (42) facing away from the capacitor inner core (51) and the clamping bracket (41). Filling balls (47) are filled in the filling space (412). The particle diameter value of the filling balls (47) is greater than the height difference between the top of the covering strip (42) and the top of the capacitor inner core (51); Vibrators (413) are arranged on the clamping brackets (41). The vibrators (413) are fixedly installed outside the clamping brackets (41). A capacity regulator (414) is further arranged in the filling space (412). The capacity regulator (414) is of a plug column structure. The capacity regulator (414) is slidably inserted into the side wall of the clamping bracket (41), and one end of the capacity regulator (414) extends into the filling space (412).

2. The preparation device of a high-temperature polypropylene film capacitor according to claim 1, characterized in that: An end pressing piece (46) is arranged at one end of the fixing space of the clamping bracket (41) corresponding to the open side, and a transfer pressing piece (45) is arranged at the other end. The positions of the transfer pressing piece (45) in one group of the clamping brackets (41) and the end pressing piece (46) in the corresponding other group of the clamping brackets (41) correspond to each other. The end pressing piece (46) and the transfer pressing piece (45) are both connected with the clamping bracket (41) through elastic connecting pieces (43). A winding rotating shaft (44) is arranged at the position of the clamping bracket (41) corresponding to the transfer pressing piece (45). The winding rotating shaft (44) is rotatably installed in the clamping bracket (41). One end of the covering strip (42) is fixedly connected to the end pressing piece (46), and the other end of the covering strip (42) bypasses the transfer pressing piece (45) and is fixedly connected to the winding rotating shaft (44). A torsion elastic piece is arranged between the winding rotating shaft (44) and the clamping bracket (41).

3. The preparation device of a high-temperature polypropylene film capacitor according to claim 2, characterized in that: A cylindrical support piece (451) is arranged at the position of the transfer pressing piece (45) corresponding to the covering strip (42). The cylindrical support piece (451) is rotatably arranged on the transfer pressing piece (45). The covering strip (42) forms an arc-shaped structure at the outer side position of the transfer pressing piece (45). A wedge-shaped filling structure is arranged at the position of the end pressing piece (46) corresponding to the arc-shaped structure.

4. The preparation device for a high-temperature polypropylene film capacitor according to claim 3, wherein: The gold spraying component (2) further includes a nozzle driver (22) for driving the gold spraying nozzle (21) to move. A tray driver (11) is arranged in the gold spraying machine (1). The tray (3) is installed on the tray driver (11), and the tray driver (11) is used to drive the tray (3) to move. The moving direction of the tray (3) is perpendicular to the moving direction of the gold spraying nozzle (21).

5. The preparation device of a high-temperature polypropylene film capacitor according to claim 4, characterized in that: The clamping driver (31) includes a bidirectional threaded screw rod (311) rotatably installed in the tray (3). The bottom of the clamping frame (41) is fixedly connected with a slider structure (411). The slider structure (411) is slidably arranged in the tray (3). The bidirectional threaded screw rod (311) penetrates through the slider structures (411) of each group of clamping frames (41). A set of threads is respectively arranged at the positions of the bidirectional threaded screw rod (311) corresponding to the two groups of clamping frames (41) in each group of inner core fixing components (4), and the rotation directions of the mutually corresponding two sets of threads are opposite. The slider structure (411) is threadedly connected with the bidirectional threaded screw rod (311) through threads. A screw rod rotation driver (312) is further arranged on the tray (3) for driving the bidirectional threaded screw rod (311) to rotate.

6. The preparation device of a high-temperature polypropylene film capacitor according to claim 5, characterized in that: The tray driver (11) is a conveying structure. A loading port (12) and an unloading port (13) are respectively arranged at both ends of the gold spraying machine (1) corresponding to the conveying structure. A quick-release structure for docking with the tray (3) is arranged on the conveying structure. The tray (3) is detachably connected to the conveying structure through the quick-release structure.

7. A high-temperature polypropylene film capacitor prepared by using the preparation device according to claim 6, characterized in that: It includes a capacitor body (5). The capacitor body (5) includes a capacitor inner core (51). Metal conductive layers (52) are formed at both ends of the capacitor inner core (51) through gold spraying processing by the gold spraying machine (1). The capacitor inner core (51) is wound from an inner core base material. The inner core base material includes a film dielectric (511). A metal electrode layer (512) is formed on the film dielectric (511) through evaporation plating processing. The film dielectric (511) is prepared by adding antioxidants and high-temperature heat stabilizers to polypropylene plastic particles.

8. A preparation method for preparing the high-temperature polypropylene film capacitor described in claim 7, characterized in that, It includes the following steps: Step 1: Processing of the film dielectric (511). Prepare polypropylene plastic particles, add antioxidants and high-temperature heat stabilizers, melt and then extrude and form, and stretch to form the film dielectric (511); Step 2: Heat treatment of the film dielectric (511). Heat the film dielectric (511) obtained in Step 1 and perform annealing treatment; Step 3: Preparation of the inner core base material. Wind and cut the film dielectric (511) obtained in Step 2, and then evaporate and deposit a metal electrode layer (512) on the surface of the film dielectric (511) through an evaporation plating device, and then cut it according to the required size to form the inner core base material; Step 4: Inner core preparation. Wind two inner core substrates together face to face to form a coil, and then perform hot pressing and shaping on the coil through a hot pressing device to form a capacitor inner core (51). After shaping, perform vacuum drying on the capacitor inner core (51). Step 5: Gold spraying process. Place the capacitor inner core (51) in two corresponding sets of clamping brackets (41), and control the two sets of clamping brackets (41) to move closer to each other so that the covering strip (42) covers the outer wall of the capacitor inner core (51) and fixes the capacitor inner core (51). Then, turn on the gold spraying nozzle (21) and control the movement of the gold spraying nozzle (21) to perform gold spraying on the end surface of the capacitor inner core (51), so that a metal conductive layer (52) is formed at the end of the capacitor inner core (51). Step 6: Welding and encapsulation. Weld leads to the metal conductive layers (52) at both ends of the capacitor inner core (51), and then place the capacitor inner core (51) in an encapsulation shell for injection molding encapsulation to form a thin film capacitor product.

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