Thin-film capacitor core vacuum heat treatment clamp and process thereof

Abstract

The vacuum heat treatment clamp applies a certain pressure to the capacitor core, the core is in an inert gas and negative pressure environment for staged heating, finally, a heat conduction box body is slowly deflated, and after the air pressure in the heat conduction box body is balanced with the atmospheric pressure, the heat conduction box body is opened, so that the capacitor core is subjected to vacuum heat treatment. And taking out the capacitor core. According to the process, the capacitor core is located in the negative pressure inert gas environment, the product is isolated from air and is not oxidized, gas in the product can be easily exhausted through the negative pressure environment, and an internal air gap is eliminated; the capacitor core is located in the middle of the heat treatment clamp, different portions of the capacitor core are evenly heated, product shrinkage is even and consistent, and the voltage resistance and the charging and discharging capacity of a capacitor are obviously improved.

Description

Technical Field

[0001] The invention relates to a film capacitor core processing technology, in particular to a film capacitor core vacuum heat treatment fixture and a process thereof. Background Art

[0002] With the development of emerging industries such as high-power pulse power supplies, new energy, and electric vehicles, capacitors, as key components in these industries, are also continuously moving towards miniaturization and high capacity, with ever-increasing energy density and ever-shrinking size. Compared with traditional round capacitor cores, flat metallized film capacitor cores have a higher duty cycle, which facilitates the miniaturization of finished capacitors. As a result, flat metallized film capacitor cores are becoming increasingly common in the field of high-capacity, high-energy storage density capacitors.

[0003] Furthermore, the metallized polypropylene film commonly used in film capacitors utilizes a heat treatment process during processing to cause the polypropylene film to shrink in both the radial and transverse directions, squeezing out any moisture remaining within the film during winding to improve film density. To maximize the high energy storage density of film capacitors, improving the capacitor core's duty cycle and withstand voltage is crucial. Consequently, high-energy-storage film capacitors often utilize flat core structures. Incomplete heat treatment can easily lead to tight film adhesion and the presence of air bubbles within the product, resulting in poor withstand voltage capability and severely impacting the product's electrical performance and reliability.

[0004] Traditional hot pressing methods for flat metallized film capacitor cores are divided into atmospheric hot pressing and vacuum hot pressing. Atmospheric hot pressing involves placing the capacitor core on a metal fixture with a certain pressure. The fixture and capacitor core are then placed in an atmospheric oven. The temperature is then set, the oven is heated to the target temperature, held at that temperature for a specified period, and then cooled naturally. Vacuum hot pressing involves placing the capacitor core on a metal fixture with a certain pressure. The fixture and capacitor core are then placed in a vacuum oven. The temperature is then set, the oven is heated to the target temperature, held at that temperature for a specified period, and then cooled naturally.

[0005] The traditional atmospheric environment hot pressing method places the capacitor core directly in the atmospheric environment for heating. This can ensure that the core is heated evenly during the heat treatment process, but it has the following defects: (1) The capacitor core is directly placed in the atmospheric environment, which is not conducive to the discharge of air remaining inside the core during the winding process, affecting the capacitor's voltage resistance; (2) During the heat treatment process, the oxygen in the air will cause an oxidation reaction on the metallized layer of the metallized film and the terminal electrodes of the core at high temperatures, which will increase the loss of the capacitor core and affect the internal resistance and current resistance of the capacitor.

[0006] The traditional vacuum hot pressing method can effectively prevent oxidation of the capacitor's internal electrodes, reduce capacitor losses, and improve the capacitor's current resistance. However, it has the following drawbacks: (1) The air in the vacuum oven is thin and there is no air convection. The heat transfer in the oven mainly relies on radiation heating. The temperature difference at different positions in the oven is large, and the core is heated unevenly.

[0007] (2) The core is placed directly inside the vacuum oven, and the core contacts the inner wall of the box, resulting in uneven heat transfer, uneven heating of the core, inconsistent shrinkage, and air gaps and stress inside the product, resulting in poor consistency in the withstand voltage level and charge and discharge life between capacitor cores in the same batch, thereby affecting the withstand voltage and charge and discharge capabilities of the finished capacitor products.

[0008] (3) A large number of capacitor cores are placed in a vacuum oven, and then vacuumed. After the vacuum degree is reached, heating is started. Continuous production cannot be achieved. The efficiency of hot pressing treatment is extremely low, and the cost of large vacuum ovens is very high. As a result, vacuum hot pressing treatment has not been widely adopted. Summary of the Invention

[0009] The first object of the present invention is to provide a vacuum heat treatment fixture for a film capacitor core which has a reasonable structure and can realize vacuum clamping or gas injection.

[0010] The first object of the present invention is achieved in this way: A vacuum heat treatment fixture for a film capacitor core comprises a heat-conducting box body, wherein a sealed cavity for placing the capacitor core is provided inside the heat-conducting box body, an air pipe for connecting to an air extraction device or an air filling device is further provided on the heat-conducting box body, and a valve is provided on the air pipe. An opening is provided on one side of the heat-conducting box body, a cover plate is connected to the opening, and the cover plate and the opening are sealed by a sealing ring; the pressing force between the cover plate and the opening is adjustable, and pressure is applied to the capacitor core directly or indirectly through the cover plate; or, a clamping device for clamping the capacitor core is provided inside the sealed cavity.

[0011] The first object of the present invention can also be solved by the following technical measures: As a more specific solution, a pressure gauge is further provided on the heat-conducting box body, and an air pressure collecting channel of the pressure gauge is communicated with the sealed cavity.

[0012] As a further embodiment, the thermally conductive housing is cubical in shape, with the opening located on its top surface and a recessed platform formed on the inner edge of the opening. The sealing ring is positioned on the recessed platform, and the cover is positioned within the opening and rests on the sealing ring. The air pipe is located on the side of the thermally conductive housing. This ensures that the upper and lower surfaces of the capacitor core maintain close contact with the bottom and top (bottom of the cover) of the sealed cavity of the thermally conductive housing, allowing for rapid temperature transfer between the inside and outside of the fixture and minimizing the temperature difference. This ensures even heating of the capacitor core when the fixture is heated in the atmosphere of a heating chamber.

[0013] As a further solution, the cover plate is connected to the heat-conducting box body by bolts.

[0014] As a further solution, the clamping device includes a bracket, a lower pressure plate, a compression spring, an upper pressure plate and an adjusting nut. The bracket is provided with a accommodating cavity for placing the compressed capacitor core. A plurality of guide columns are distributed on the accommodating cavity. The lower pressure plate and the upper pressure plate are provided with sleeve holes corresponding to the guide columns. The lower pressure plate covers the accommodating cavity and is sleeved with the guide columns through its sleeve holes. Each guide column is sleeved with the compression spring. The upper pressure plate is sleeved with the guide column through its sleeve holes and is placed on the compression spring; the adjusting nut is threadedly connected to the upper end of the guide column and is crimped on the upper pressure plate.

[0015] As a further solution, the surfaces of the heat-conducting box and cover facing the sealed cavity are polished. The internal surface is polished to improve the surface flatness of the capacitor core after finalization, while also reducing the air gap between the capacitor core surface and the sealed cavity, thereby reducing contact thermal resistance and improving heat transfer efficiency.

[0016] The second object of the present invention is to provide a vacuum heat treatment process for a thin film capacitor core that can form a certain degree of vacuum, form convection heating, and avoid electrode oxidation.

[0017] The second object of the present invention is achieved in this way: A vacuum heat treatment process for a film capacitor core is characterized in that: the capacitor core is encapsulated in a heat-conducting box, a certain pressure is applied to the capacitor core, the heat-conducting box is filled with inert gas, and the vacuum degree is within the range of -0.02 to -0.1 MPa; the pressure on the capacitor core during the hot pressing process can be controlled by the inert gas pressure in the hot pressing fixture; the capacitor core is isolated from the air in the inert gas environment to prevent the metallization layer of the capacitor core from being oxidized during the hot pressing process.

[0018] The heat conduction box and the capacitor core are placed in a heating chamber for heating. The heating process includes the following stages: The first stage of heating: room temperature ~ 85 ° C, heating time 30min ~ 60min; The second stage of heat preservation: 85℃, heat preservation time 4h; The third stage of heating: 85℃~maximum temperature, heating time 30min~60min, maximum temperature is a temperature within the range of 100℃~150℃; The fourth stage of heat preservation: the highest temperature, heat preservation time 12h ~ 30h; The fifth stage of cooling: the highest temperature ~30℃, 2h~5h; Finally, take out the heat conduction box, slowly release the air from the box, wait until the air pressure inside the box is balanced with the atmospheric pressure, open the box, and take out the capacitor core.

[0019] As a further solution, the end face of the capacitor core is separated from the interior of the heat conduction box by a certain distance to form a gas flow space.

[0020] As a further solution, the capacitor core is encapsulated in a heat-conducting box, which is first vacuumed until the vacuum degree inside the box reaches -0.1 MPa; then, inert gas is filled into the heat-conducting box.

[0021] As a further solution, the capacitor core is a flat core structure or a round core structure.

[0022] The beneficial effects of the present invention are as follows: (1) The present invention can effectively solve the problem of water vapor generated inside the core of a large-sized flat core capacitor during heat treatment, thereby improving the energy storage density, service life, and ultimate withstand voltage strength of the film capacitor.

[0023] (2) The present invention is particularly suitable for heat treatment of metallized polypropylene film capacitor cores to meet the market demand for capacitors with high energy storage, small size, light weight and long life.

[0024] (3) The present invention can effectively solve the problems of vacuum processing technology, high power of vacuum equipment, high environmental noise, and poor internal temperature consistency. (4) The present invention can effectively solve the problem of rapid assembly line operation of vacuum processing technology, and ensure that the product can be produced in batches, mass-produced, and unitized in the industry.

[0025] (5) The present invention realizes uniform temperature and controllable pressure during the hot pressing process of the flat capacitor core, improves the core's thermal shrinkage and pressure uniformity, reduces residual air gaps and stress inside the core, improves the core surface flatness, reduces the capacitor core's dielectric loss, and enhances the capacitor core's voltage and current resistance capabilities, making it easier to realize continuous production during the hot pressing process and improving production efficiency.

[0026] (6) The heat treatment fixture of the present invention is miniaturized and easy to circulate, and the cavity volume is small and the internal pressure is easy to adjust, which can save inert gas.

[0027] (8) The capacitor core of the present invention is subjected to a single hot pressing treatment by a hot pressing fixture. After the single fixture treatment, it can be quickly circulated, thereby reducing its circulation time, improving production efficiency, and realizing continuous production.

[0028] (9) The heat-conducting box of the present invention is made of metal material with high thermal conductivity, which improves the heat conduction efficiency between the surface of the capacitor core and the external environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the exploded structure of the first clamp and capacitor core of the present invention.

[0030] Figure 2 This is a schematic diagram of the three-dimensional structure of the first clamp of the present invention.

[0031] Figure 3 This is a schematic diagram of the top view of the first clamp of the present invention.

[0032] Figure 4 for Figure 3 AA cross-sectional structural diagram.

[0033] Figure 5 for Figure 4 BB cross-sectional structure diagram.

[0034] Figure 6 It is a schematic structural diagram of a plurality of first-type clamps of the present invention being clamped by an air pressure platform.

[0035] Figure 7 This is a schematic diagram of the exploded structure of the second clamp and multiple capacitor cores of the present invention.

[0036] Figure 8 This is a schematic diagram of the three-dimensional structure of the second clamp of the present invention.

[0037] Figure 9 This is a schematic diagram of the top view of the second clamp structure of the present invention.

[0038] Figure 10 for Figure 9 Schematic diagram of the CC cross-sectional structure.

[0039] Figure 11 for Figure 10 DD cross-sectional structure diagram.

[0040] Figure 12 This is a schematic cross-sectional view of the third clamp of the present invention.

[0041] Figure 13 This is a schematic cross-sectional view of the fourth clamp of the present invention.

[0042] Figure 14 This is a diagram showing the relationship between time and temperature during the heat treatment process of the present invention. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1, see Figures 1 to 5As shown, a vacuum heat treatment fixture 10 for a film capacitor core comprises a heat-conducting box body 1, wherein a sealed cavity 11 for placing a capacitor core 20 is provided in the heat-conducting box body 1, and an air pipe 3 for connecting to an air extraction device or an air filling device is further provided on the heat-conducting box body 1, and a valve 31 is provided on the air pipe 3. An opening is provided on one side of the heat-conducting box body 1, and a cover plate 5 is connected to the opening. The cover plate 5 and the opening are sealed by a sealing ring 4; the pressing force between the cover plate 5 and the opening is adjustable, and pressure is applied to the capacitor core 20 directly or indirectly through the cover plate 5.

[0044] The heat-conducting box 1 is also provided with a pressure gauge 2, and the pressure collection channel of the pressure gauge 2 is connected to the sealed cavity 11. The pressure gauge 2 can be fixed, that is, the pressure gauge needs to be heated together during heat treatment; or it can be designed to be detachable, that is, it can be removed after monitoring is completed.

[0045] The heat-conducting box body 1 is in a cubic shape, the opening is located on its top surface, a sink is provided on the inner edge of the opening, the sealing ring 4 is arranged on the sink, the cover plate 5 is arranged in the opening and supported on the sealing ring 4, and the air pipe 3 and the pressure gauge 2 are located on the side of the heat-conducting box body 1.

[0046] Specifically, a concave groove is formed on the sink, and a sealing ring 4 is placed within the groove, 3-5 mm above the groove. This ensures a certain degree of compression between the heat-conducting box 1 and the cover 5 during vacuum treatment, thereby ensuring a certain degree of sealing of the sealed cavity of the vacuum heat treatment fixture. The internal dimensions of the vacuum heat treatment fixture (sealed cavity) are optimally selected based on the dimensions of the capacitor core 20.

[0047] The surfaces of the heat-conducting housing 1 and cover plate 5 facing the sealed cavity 11 are polished. The vacuum heat treatment fixture (heat-conducting housing 1 and cover plate 5) is made of a lightweight, sealed metal material (such as aluminum). The interior of the housing is polished to ensure that after oven heating, the overall oven temperature maintains the fixture temperature. This heat is then rapidly transferred through the fixture to the interior, where it rapidly heats the capacitor core through thermal radiation, ensuring consistent internal temperature.

[0048] In this embodiment, the heat-conducting box 1 is in the shape of a relatively flat cube, which is suitable for clamping a single flat-core capacitor core.

[0049] Combine Figure 6 As shown, the film capacitor core vacuum heat treatment fixture 10 is assembled by the air pressure platform 6; the air pressure platform 6 includes a workbench, a stand 61 and a pressure cylinder 62, the stand 61 is set on the workbench, a hanging plate is provided on the top of the stand 61, the pressure cylinder 62 is set on the hanging plate, and a clamping area is formed between the hanging plate and the workbench, the vacuum heat treatment fixture 10 is set in the clamping area and is pressed down and assembled by the pressure cylinder 62.

[0050] The clamping process of the film capacitor core vacuum heat treatment fixture 10 is as follows: put a flat capacitor core 20 into the opened sealed cavity 11, and then put the sealing ring 4 and the cover plate 5; if there are multiple sets of fixtures, the fixtures can be stacked and placed on the air pressure table 6, and all the cover plates 5 are pressed together. Figure 6 Then, connect the air pipe 3 to the vacuum pump and open the valve 31 to evacuate the air. After evacuation, close the valve 31, replace the vacuum pump with an inert gas injection device, open the valve 31, and inject an appropriate amount of inert gas. Finally, close the valve 31 and remove the inert gas injection device to complete the fixture clamping process.

[0051] Among them, the pressure gauge 2 of the fixture is used to monitor the negative pressure value during vacuuming, the pressure change when the inert gas is injected, etc., to determine whether the installation of the fixture meets the requirements.

[0052] After the vacuum heat treatment fixture 10 is evacuated, the cover plate 5 can be tightened to a certain extent.

[0053] The difference between the second embodiment and the first embodiment is that: Figures 7 to 11 As shown, the sealed cavity 11 of the thin film capacitor core vacuum heat treatment fixture 10 is relatively deep, and multiple capacitor cores 20 can be stacked at the same time. The capacitor cores are separated by partitions 7, and partitions 7 can also be placed on the top surface of the uppermost capacitor core 20.

[0054] The partition 7 is made of stainless steel plate / anodized aluminum plate (heat conducting plate).

[0055] The cover plate 5 can also be pressed by an air pressure platform as in the first embodiment.

[0056] The difference between the third embodiment and the first embodiment is that: Figure 12 As shown, the cover plate 5 is connected to the heat conduction box 1 by bolts 51. The air pipe 3 and the pressure gauge 2 are located on the cover plate 5 of the heat conduction box 1. There is no sink inside the opening of the sealed cavity 11, and the sealing ring 4 is directly placed on the top surface of the opening.

[0057] The sealed chamber 11 of the film capacitor core vacuum heat treatment fixture 10 is deep enough to accommodate multiple capacitor cores 20 stacked simultaneously. The capacitor cores are separated by partitions 7, and a partition 7 is also placed on the top surface of the topmost capacitor core 20. Compression springs 8 are placed at the four corners of the topmost partition 7. The pressure of the compression springs 8 is ≥100kg, ensuring that the film layers within the vacuum heat treatment are tightened and the pressure on the core remains constant during the heat treatment process. The cover plate 5 is tightened and sealed with bolts 51.

[0058] The method of evacuating the sealed cavity 11 and injecting the inert gas is the same as that of the first and second embodiments.

[0059] The fourth embodiment differs from the third embodiment in that: Figure 13 As shown, a clamping device for clamping the capacitor core 20 is provided inside the sealed cavity 11 of the film capacitor core vacuum heat treatment fixture 10.

[0060] The clamping device includes a bracket 9, a lower pressure plate 92, a compression spring 8, an upper pressure plate 93 and an adjusting nut 94. The bracket 9 is provided with a accommodating cavity for placing the compressed capacitor core 20, and a plurality of guide columns 91 are distributed on the accommodating cavity. The lower pressure plate 92 and the upper pressure plate 93 are both provided with sleeve holes corresponding to the guide columns 91. The lower pressure plate 92 covers the accommodating cavity and is sleeved with the guide columns 91 through its sleeve holes. Each guide column 91 is sleeved with the compression spring 8. The upper pressure plate 93 is sleeved with the guide column 91 through its sleeve holes and is placed on the compression spring 8; the adjusting nut 94 is threadedly connected to the upper end of the guide column 91 and is crimped on the upper pressure plate 93.

[0061] A plurality of capacitor cores 20 can be stacked in the accommodation cavity, and the capacitor cores are separated by partitions 7 , and the capacitor core 20 on the top layer directly contacts the bottom surface of the lower pressing plate 92 .

[0062] A vacuum heat treatment process for a thin film capacitor core, wherein the capacitor core 20 is encapsulated in a heat-conducting box 1, a certain pressure is applied to the capacitor core 20, the heat-conducting box 1 is filled with an inert gas, and the vacuum degree is within the range of -0.02 to -0.1 MPa; wherein the capacitor core 20 can be encapsulated in any of the above-mentioned embodiments 1 to 4, and in addition, a distance of 1 mm to 20 mm is maintained between the four sides of the capacitor core 20 and the four walls of the sealed cavity 11 (combined with Figure 5 As shown, the four distances are D1, D2, D3, and D4).

[0063] The heat-conducting box 1 is first evacuated to remove air, with a vacuum degree of -0.1 MPa; then a small amount of inert gas such as nitrogen, argon or helium is filled therein to make the vacuum degree within the range of -0.02 to -0.1 MPa.

[0064] The above operation can be repeated to obtain a series of hot pressing fixtures equipped with capacitor cores.

[0065] The heat conducting box 1 (heat pressing fixture) and the capacitor core 20 are placed in the heating chamber for heating treatment. The heating treatment includes the following stages (the relationship between temperature and time is shown in Figure 14 shown): The first stage of heating: room temperature ~ 85 ° C, heating time 30min ~ 60min; The second stage of heat preservation: 85℃, heat preservation time 4h; The third stage of heating: 85℃~maximum temperature, heating time 30min~60min, maximum temperature is a temperature within the range of 100℃~150℃; The fourth stage of heat preservation: the highest temperature, heat preservation time 12h ~ 30h; The fifth stage of cooling: the highest temperature is ~30℃, 2h~5h; Finally, take out the heat-conducting box 1, slowly release the air from the heat-conducting box 1, wait until the air pressure in the heat-conducting box 1 is balanced with the atmospheric pressure, open the heat-conducting box 1, and take out the capacitor core 20.

[0066] The capacitor core 20 is a flat core structure. If it is used for vacuum heat treatment of a capacitor core with a round core structure, a curved surface partition should be used to clamp the round capacitor core, which is not shown in the figure.

[0067] The heating chamber can be an oven or a tunnel heating furnace. When a tunnel heating furnace is adopted, a multi-temperature zone tunnel heating furnace heat treatment process can be used, and the temperature curve during the heat treatment process can be more precisely controlled.

[0068] The above process places the capacitor core in a negative pressure inert gas environment, ensuring that the product is isolated from the air and prevented from oxidation. The negative pressure environment also facilitates the discharge of gas inside the product, eliminating internal air gaps. The capacitor core is located in the middle part of the heat treatment fixture, and different parts of the capacitor core are heated evenly, resulting in uniform product shrinkage, which significantly improves the capacitor's voltage resistance and charge and discharge capabilities.

[0069] The above is a preferred embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A vacuum heat treatment fixture for a film capacitor core, comprising a heat-conducting box (1), characterized in that: The heat-conducting box (1) is provided with a sealed cavity (11) for placing the capacitor core (20), and the heat-conducting box (1) is also provided with an air pipe (3) for connecting to an air extraction device or an air filling device, and the air pipe (3) is provided with a valve (31). An opening is provided on one side of the heat-conducting box (1), and a cover plate (5) is connected to the opening. The cover plate (5) and the opening are sealed by a sealing ring (4); The pressing force between the cover plate (5) and the opening is adjustable, and pressure is applied directly or indirectly to the capacitor core (20) through the cover plate (5); or, a clamping device for clamping the capacitor core (20) is provided inside the sealed cavity (11).

2. The vacuum heat treatment fixture for film capacitor core according to claim 1, characterized in that: A pressure gauge (2) is also provided on the heat-conducting box body (1), and an air pressure collection channel of the pressure gauge (2) is in communication with the sealed cavity (11).

3. The vacuum heat treatment fixture for film capacitor core according to claim 2, characterized in that: The heat-conducting box body (1) is in a cubic shape, the opening is located on its top surface, a sink is provided on the inner edge of the opening, the sealing ring (4) is arranged on the sink, the cover plate (5) is arranged in the opening and supported on the sealing ring (4), and the air pipe (3) is located on the side of the heat-conducting box body (1).

4. The vacuum heat treatment fixture for film capacitor core according to claim 2, characterized in that: The cover plate (5) is connected to the heat-conducting box body (1) via bolts.

5. The vacuum heat treatment fixture for film capacitor core according to claim 1, characterized in that: The clamping device comprises a bracket (9), a lower pressing plate (92), a compression spring (8), an upper pressing plate (93) and an adjusting nut (94); the bracket (9) is provided with a receiving cavity for placing the compressed capacitor core (20); a plurality of guide columns (91) are distributed on the receiving cavity; the lower pressing plate (92) and the upper pressing plate (93) are provided with sleeve holes corresponding to the guide columns (91); the lower pressing plate (92) covers the receiving cavity and is sleeved with the guide columns (91) through its sleeve holes; each guide column (91) is sleeved with the compression spring (8); the upper pressing plate (93) is sleeved with the guide columns (91) through its sleeve holes and is supported on the compression spring (8); the adjusting nut (94) is threadedly connected to the upper end of the guide column (91) and is press-fitted on the upper pressing plate (93).

6. The vacuum heat treatment fixture for film capacitor core according to claim 1, characterized in that: The surfaces of the heat-conducting box body (1) and the cover plate (5) facing the sealed cavity (11) are smooth.

7. A vacuum heat treatment process for a thin film capacitor core, characterized by: The capacitor core (20) is encapsulated in a heat-conducting box (1), and a certain pressure is applied to the capacitor core (20). The heat-conducting box (1) is filled with an inert gas and its vacuum degree is within the range of -0.02 to -0.1 MPa; The heat conducting box (1) and the capacitor core (20) are placed in a heating chamber for heating treatment, and the heating treatment includes the following stages: The first stage of heating: room temperature ~ 85 ° C, heating time 30min ~ 60min; The second stage of heat preservation: 85℃, heat preservation time 4h; The third stage of heating: 85℃~maximum temperature, heating time 30min~60min, maximum temperature is a temperature within the range of 100℃~150℃; The fourth stage of heat preservation: the highest temperature, heat preservation time 12h ~ 30h; The fifth stage of cooling: the highest temperature ~30℃, 2h~5h; Finally, the heat conduction box (1) is taken out, and the air in the heat conduction box (1) is slowly released. When the air pressure in the heat conduction box (1) is balanced with the atmospheric pressure, the heat conduction box (1) is opened, and the capacitor core (20) is taken out.

8. The vacuum heat treatment process for a thin film capacitor core according to claim 7, characterized in that: The end surface of the capacitor core (20) is separated from the interior of the heat-conducting box (1) by a certain distance to form a gas flow space.

9. The vacuum heat treatment process for a thin film capacitor core according to claim 7, characterized in that: The capacitor core (20) is encapsulated in a heat-conducting box (1). The heat-conducting box (1) is first vacuumed until the vacuum degree in the heat-conducting box (1) reaches -0.1 MPa; then, an inert gas is filled into the heat-conducting box (1).

10. The vacuum heat treatment process for a thin film capacitor core according to claim 7, characterized in that: The capacitor core (20) is a flat core structure or a round core structure.

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