A film capacitor and a method for preparing the same

Abstract

The present invention provides a thin film capacitor and a preparation method thereof, and relates to the technical field of capacitors. In the present invention, when the capacitor core is heat-set, an inert gas is used as a heat-conducting gas, and the space between the film layers of the thin film capacitor is filled with the inert gas, so that the water vapor between the film layers of the thin film capacitor can be removed. Since the inert gas is relatively stable, it is not easy to be ionized under the action of electrical stress and thermal stress, so the loss of the thin film capacitor can be reduced. In addition, in the embodiment of the present invention, in the final stage of heat setting heating, multiple cooling-heating treatments are performed within a certain temperature range, so that the metallized film in the capacitor core repeatedly expands and contracts, which is beneficial to remove the water vapor inside the metallized film material, thereby helping to further reduce the loss of the film capacitor. In summary, the film capacitor prepared by the method of the present invention has a small loss, which is beneficial to improving the service life of the capacitor.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a film capacitor and a method for preparing the same. Background Art

[0002] As an important electronic component, film capacitors are widely used in electronics, electricity, communications and other fields. They have the advantages of high capacity, low equivalent series resistance, good stability and long life. They play an important role in power filtering, signal transmission, motor starting, frequency converters, inverters and other equipment. The general production process of film capacitors is winding-static pressing-heat setting-gold spraying-energizing-core welding-core preheating-glue injection-curing. However, the loss (DF) of film capacitors produced using related technologies is large, which seriously affects the service life of film capacitors. Summary of the invention

[0003] The problem solved by the present invention is: how to further reduce the loss of the film capacitor.

[0004] In order to solve the above problems, the present invention provides a method for preparing a thin film capacitor, comprising:

[0005] Step S1, heat-setting the capacitor core to obtain a heat-set capacitor core;

[0006] Step S2, spraying gold, energizing, core welding, core preheating, glue injection and curing the heat-set capacitor core in sequence to obtain a thin film capacitor;

[0007] Among them, in the step S1, the heat setting of the capacitor core includes: placing the capacitor core in an oven, filling the oven with inert gas as a heat-conducting gas, raising the temperature of the oven to 95°C to 100°C, keeping it warm for 3.5h to 4.5h, and subjecting the temperature of the oven to multiple cooling-heating treatments to obtain the heat-set capacitor core; the cooling-heating treatment includes: cooling the temperature of the oven from 95°C to 100°C to 85°C to 90°C, keeping it warm for 1.5h to 2.5h, and then raising the temperature to 95°C to 100°C, and keeping it warm for 3.5h to 4.5h.

[0008] Optionally, in step S1, raising the temperature of the oven to 95°C to 100°C includes: raising the temperature of the oven to 55°C to 60°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 65°C to 70°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 75°C to 80°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 85°C to 90°C, keeping it warm for 1.5h to 2.5h, and then raising the temperature to 95°C to 100°C.

[0009] Optionally, in step S1, the temperature of the oven is subjected to three cooling-heating treatments.

[0010] Optionally, in step S1, the inert gas is at least one of helium, neon, argon, krypton and xenon.

[0011] Optionally, in step S1, the capacitor core is formed by winding and static pressing a metallized film.

[0012] Optionally, the metallized film is a metallized polypropylene film.

[0013] Optionally, in step S2, the core welding is performed using a core copper busbar.

[0014] Optionally, in step S2, the core is preheated at a temperature of 60°C to 70°C.

[0015] Optionally, the core is preheated for 7 to 9 hours.

[0016] The present invention also provides a thin film capacitor, which is manufactured using the above-mentioned method for manufacturing the thin film capacitor.

[0017] Compared with the related art, in the present invention, when the capacitor core is heat-set, an inert gas is used as a heat-conducting gas, and the space between the film layers of the thin film capacitor is filled with the inert gas, so that the water vapor between the film layers of the thin film capacitor can be removed. Since the inert gas is relatively stable in nature, it is not easy to be ionized under the action of electrical stress and thermal stress, so the loss of the thin film capacitor can be reduced. In addition, in the embodiment of the present invention, in the final stage of heat setting heating, multiple cooling-heating treatments are performed within a certain temperature range (85°C to 100°C), so that the metallized film in the capacitor core repeatedly expands and contracts, which is beneficial to remove the water vapor inside the metallized film material, thereby further reducing the loss of the film capacitor. In summary, the film capacitor produced by the method of the present invention has a small loss, which is beneficial to increase the service life of the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a schematic diagram of the process flow of the preparation method of the thin film capacitor. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0022] The general production process of film capacitors is winding-static pressing-heat setting-gold spraying-energizing-core welding-core preheating-glue injection-curing. However, the film capacitors produced using related technologies have large losses, which seriously affect the service life of film capacitors. At present, when heat setting the capacitor core, air is generally used as a heat-conducting gas for heating. Studies have found that after heat setting the capacitor core in this way, there will be some water vapor between the film layers of the capacitor core. Under the action of electrical stress and thermal stress, the water vapor will ionize and corrode the metal coating in the capacitor. Therefore, the loss of film capacitors is large, which affects the service life of the capacitor.

[0023] Based on the above considerations, if Figure 1 As shown, a method for preparing a thin film capacitor provided by an embodiment of the present invention includes:

[0024] Step S1, heat-setting the capacitor core to obtain a heat-set capacitor core;

[0025] Step S2, spraying gold, energizing, core welding, core preheating, glue injection and curing the heat-set capacitor core in sequence to obtain a thin film capacitor;

[0026] Among them, in the step S1, the heat setting of the capacitor core includes: placing the capacitor core in an oven, filling the oven with inert gas as a heat-conducting gas, raising the temperature of the oven to 95°C to 100°C, keeping it warm for 3.5h to 4.5h, and subjecting the temperature of the oven to multiple cooling-heating treatments to obtain the heat-set capacitor core; the cooling-heating treatment includes: cooling the temperature of the oven from 95°C to 100°C to 85°C to 90°C, keeping it warm for 1.5h to 2.5h, and then raising the temperature to 95°C to 100°C, and keeping it warm for 3.5h to 4.5h.

[0027] In the embodiment of the present invention, when the capacitor core is heat-set, an inert gas is used as a heat-conducting gas, and the space between the film layers of the thin film capacitor is filled with the inert gas, so that the water vapor between the film layers of the thin film capacitor can be removed. Since the inert gas is relatively stable in nature, it is not easy to be ionized under the action of electrical stress and thermal stress, so the loss of the thin film capacitor can be reduced. In addition, in the embodiment of the present invention, in the final stage of heat setting heating, multiple cooling-heating treatments are performed within a certain temperature range (85°C to 100°C), so that the metallized film in the capacitor core repeatedly expands and contracts, which is beneficial to remove the water vapor inside the metallized film material, thereby further reducing the loss of the thin film capacitor. In summary, the thin film capacitor produced by the method of the embodiment of the present invention has a small loss, which is beneficial to increase the service life of the capacitor.

[0028] In some embodiments of the present invention, in step S1, raising the temperature of the oven to 95°C to 100°C includes: raising the temperature of the oven to 55°C to 60°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 65°C to 70°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 75°C to 80°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 85°C to 90°C, keeping it warm for 1.5h to 2.5h, and then raising the temperature to 95°C to 100°C.

[0029] In some embodiments of the present invention, illustratively, in step S1, the temperature of the oven is subjected to three cooling-heating processes.

[0030] In some embodiments of the present invention, in step S1, the inert gas is at least one of helium, neon, argon, krypton and xenon.

[0031] In some embodiments of the present invention, in the step S1, the capacitor core is formed by winding and static pressing a metallized film.

[0032] In some embodiments of the present invention, illustratively, the metallized film is a metallized polypropylene film.

[0033] In some embodiments of the present invention, in step S2, the core welding is performed using a core copper busbar.

[0034] In some embodiments of the present invention, in step S2, the core is preheated at a temperature of 60°C to 70°C.

[0035] In some embodiments of the present invention, the core is preheated for 7 to 9 hours.

[0036] The embodiment of the present invention further provides a thin film capacitor, which is manufactured by the above-mentioned method for manufacturing the thin film capacitor.

[0037] The present invention is further described below in conjunction with specific embodiments.

[0038] Example 1

[0039] A1. The capacitor core is made by winding and static pressing metallized polypropylene film;

[0040] A2. Heat setting: placing the capacitor core in an oven, filling the oven with argon as a heat-conducting gas, raising the temperature of the oven to 60°C, keeping it warm for 2 hours, then raising the temperature to 70°C, keeping it warm for 2 hours, then raising the temperature to 80°C, keeping it warm for 2 hours, then raising the temperature to 90°C, keeping it warm for 2 hours, then raising the temperature to 100°C, keeping it warm for 4 hours, and then subjecting the temperature of the oven to two cooling-heating treatments to obtain the heat-set capacitor core; the cooling-heating treatment includes: cooling the temperature of the oven from 100°C to 90°C, keeping it warm for 2 hours, then raising the temperature to 100°C, and keeping it warm for 4 hours.

[0041] A3, spraying gold, energizing, core welding, core preheating, glue injection and curing the heat-set capacitor core in sequence to obtain a thin film capacitor;

[0042] Example 2

[0043] The difference from Example 1 is that in step A2, the temperature of the oven is subjected to three cooling-heating treatments.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that in step A2, argon gas is replaced by air.

[0046] Comparative Example 2

[0047] The difference from Example 1 is that step A2 is: placing the capacitor core in an oven, filling the oven with argon as a heat-conducting gas, raising the temperature of the oven to 60°C, keeping it warm for 2 hours, then raising the temperature to 70°C, keeping it warm for 2 hours, then raising the temperature to 80°C, keeping it warm for 2 hours, then raising the temperature to 90°C, keeping it warm for 2 hours, then raising the temperature to 100°C, and keeping it warm for 16 hours.

[0048] Comparative Example 3

[0049] The difference from Example 1 is that step A2 is: placing the capacitor core in an oven, filling the oven with air as a heat-conducting gas, raising the temperature of the oven to 60°C, keeping it warm for 2 hours, then raising the temperature to 70°C, keeping it warm for 2 hours, then raising the temperature to 80°C, keeping it warm for 2 hours, then raising the temperature to 90°C, keeping it warm for 2 hours, then raising the temperature to 100°C, and keeping it warm for 16 hours.

[0050] Experimental example

[0051] The loss of the film capacitors prepared in Examples 1 to 2 and Comparative Examples 1 to 3 is shown in Table 1. It can be seen from Table 1 that the loss of the film capacitors prepared in Examples 1 to 2 is smaller than that in Comparative Examples 1 to 3. Compared with Comparative Example 1, the loss of the film capacitor prepared in Example 1 is smaller, indicating that the use of inert gas as a heat-conducting gas for heat setting is beneficial to reducing the loss of the capacitor. Compared with Comparative Example 2, the loss of the film capacitor prepared in Example 1 is smaller, indicating that multiple cooling-heating treatments in the final stage of the heat setting process are beneficial to reducing the loss of the capacitor.

[0052] Table 1

[0053]

[0054] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for preparing a thin film capacitor, characterized in that: include: Step S1, heat-setting the capacitor core to obtain a heat-set capacitor core; wherein the capacitor core is formed by winding and static pressing a metallized film; the metallized film is a metallized polypropylene film; Step S2, spraying gold, energizing, core welding, core preheating, glue injection and curing the heat-set capacitor core in sequence to obtain a thin film capacitor; Among them, in the step S1, the heat setting of the capacitor core includes: placing the capacitor core in an oven, filling the oven with inert gas as a heat-conducting gas, raising the temperature of the oven to 95°C to 100°C, keeping it warm for 3.5h to 4.5h, and subjecting the temperature of the oven to multiple cooling-heating treatments to obtain the heat-set capacitor core; the cooling-heating treatment includes: cooling the temperature of the oven from 95°C to 100°C to 85°C to 90°C, keeping it warm for 1.5h to 2.5h, and then raising the temperature to 95°C to 100°C, and keeping it warm for 3.5h to 4.5h.

2. The method for preparing a thin film capacitor according to claim 1, characterized in that: In the step S1, raising the temperature of the oven to 95°C to 100°C includes: raising the temperature of the oven to 55°C to 60°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 65°C to 70°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 75°C to 80°C, keeping it warm for 1.5h to 2.5h, then raising the temperature to 85°C to 90°C, keeping it warm for 1.5h to 2.5h, and then raising the temperature to 95°C to 100°C.

3. The method for preparing a thin film capacitor according to claim 1, characterized in that: In the step S1, the temperature of the oven is subjected to three cooling-heating treatments.

4. The method for preparing a thin film capacitor according to claim 1, characterized in that: In the step S1, the inert gas is at least one of helium, neon, argon, krypton and xenon.

5. The method for preparing a thin film capacitor according to claim 1, characterized in that: In the step S2, the core welding is performed using a core copper busbar.

6. The method for preparing a thin film capacitor according to claim 1, characterized in that: In the step S2, the core is preheated to a temperature of 60°C to 70°C.

7. The method for preparing a thin film capacitor according to claim 6, characterized in that: The core preheating time is 7h to 9h.

8. A film capacitor, characterized in that: The thin film capacitor is manufactured by the method for preparing the thin film capacitor according to any one of claims 1 to 7.

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