Capacitor cores and metallized film wound flattened capacitors, electronic products

Abstract

The present invention provides a capacitor core, a metallized film wound flattened capacitor, and an electronic product, relating to the technical field of electronic components. In the capacitor core provided by the present invention, the metallized film used to form the capacitor core body and the insulating film used to form the protective cover (outer film) have similar transverse and longitudinal thermal shrinkage rates. Therefore, during the subsequent heat setting process, the capacitor core body and the protective cover can shrink to essentially the same degree, thereby achieving a tight fit between the protective cover and the capacitor core body. This prevents metal particles from penetrating the gap between the protective cover and the capacitor core body during the gold spraying process, thereby reducing the possibility of abnormal explosion during the energization process. Capacitors made using the capacitor core provided by the present invention are safer during subsequent use.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and in particular to a capacitor core, a metallized film wound flattened capacitor, and an electronic product. Background Art

[0002] Metallized film wound flattened capacitors have the property of "self-healing", that is, when a small part of the electrode causes a short circuit due to the fragility of the dielectric, it can self-recover and restore the insulation performance, thus showing a wide range of application prospects. The core structure of the metallized film wound flattened capacitor includes a capacitor core made of wound metallized film, a gold-sprayed layer, and electrode leads. The general production process of metallized film wound flattened capacitors is winding-flattening-heat setting-gold spraying-energizing-welding. In order to prevent the capacitor core from being corroded by the external environment and affecting its service life, an outer film is generally provided on the outside of the capacitor core as a protective cover. However, in actual production, it was found that this capacitor core with an outer film was prone to abnormal cracking in the subsequent energizing test, resulting in a high defective rate of the product. Summary of the Invention

[0003] The problem solved by the present invention is that a capacitor core with an outer film is prone to bursting abnormally during a subsequent energization test, resulting in a high defective rate of the product.

[0004] To solve the above problems, the present invention provides a capacitor core, comprising a capacitor core body and a protective cover, wherein the capacitor core body is formed by winding a metallized film, and the protective cover is made of an insulating film, the protective cover covering the outer side of the core body, and the longitudinal direction of the insulating film is the same as the longitudinal direction of the metallized film; the ratio of the transverse heat shrinkage rate of the metallized film to the transverse heat shrinkage rate of the insulating film is 1:(0.85-1.05), and the ratio of the longitudinal heat shrinkage rate of the metallized film to the longitudinal heat shrinkage rate of the insulating film is 1:(0.85-1.05).

[0005] Optionally, the metallized film is a metallized polypropylene film.

[0006] Optionally, the metal coating of the metallized polypropylene film is a zinc-aluminum alloy coating.

[0007] Optionally, the thickness of the metallized polypropylene film is 8-10 μm.

[0008] Optionally, the insulating film is a single-sided roughened polypropylene film.

[0009] Optionally, the thickness of the single-sided roughened polypropylene film is 14-16 μm.

[0010] Optionally, the insulating film is a double-sided roughened polypropylene film.

[0011] Optionally, the thickness of the double-sided roughened polypropylene film is 12-15 μm.

[0012] The present invention also provides a metallized film wound flattened capacitor, comprising the capacitor core described above.

[0013] The present invention also provides an electronic product comprising the metallized film wound flattened capacitor described above.

[0014] Compared with the prior art, the metallized film used to form the capacitor core body and the insulating film used to form the protective cover (outer film) in the capacitor core provided by the present invention have similar transverse and longitudinal thermal shrinkage rates. The ratio of the transverse thermal shrinkage rate of the metallized film to the transverse thermal shrinkage rate of the insulating film is 1:(0.85-1.05), and the ratio of the longitudinal thermal shrinkage rate of the metallized film to the longitudinal thermal shrinkage rate of the insulating film is 1:(0.85-1.05). As a result, during the subsequent heat setting process, the capacitor core body and the protective cover can shrink to a similar degree, ensuring a tight fit between the protective cover and the capacitor core body. This prevents metal particles from penetrating the gap between the protective cover and the capacitor core body during the gold spraying process, thereby reducing the possibility of explosion abnormalities during the energization process. Capacitors made using the capacitor core provided by the present invention are safer during subsequent use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of the capacitor core in an embodiment of the present invention.

[0016] Description of reference numerals:

[0017] 1. Capacitor core body; 2. Protective cover. DETAILED DESCRIPTION

[0018] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to 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 construed as being limited to the embodiments described herein. Instead, 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 for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0020] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "at least partially based 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 for descriptive purposes only 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 this application, unless otherwise specified, "multiple" means two or more.

[0021] It should be noted that the films used in this invention are all commercial films, stored or used in roll form. When an unused roll is unrolled, the film is rectangular, with the length of the film being the transverse direction and the width of the film being the longitudinal direction. The transverse and longitudinal heat shrinkage rates in this invention refer to the transverse and longitudinal heat shrinkage rates of the film, respectively, at 100°C. Figure 1 The direction indicated by the arrow Y is the longitudinal direction of the insulating film, which is also the longitudinal direction of the metallized film.

[0022] In actual production, it was found that capacitor cores with protective sleeves (outer films) were prone to cracking during subsequent energization testing, resulting in a high product defect rate (around 30%). Research has found that when the transverse and longitudinal thermal shrinkage rates of the metallized film used to prepare the capacitor core body 1 and the insulating film used to prepare the protective sleeve 2 (outer film) in the capacitor core differ significantly, the degree of shrinkage of the capacitor core body 1 and the protective sleeve 2 differ significantly during the subsequent heat setting process of the capacitor core, making it impossible to achieve a close fit between the protective sleeve 2 and the capacitor core body 1. During the gold spraying process, metal particles easily penetrate into the gap between the protective sleeve 2 and the capacitor core body 1, making the cracking phenomenon more likely during the energization process.

[0023] like Figure 1As shown, an embodiment of the present invention provides a capacitor core, including a capacitor core body 1 and a protective cover 2, wherein the capacitor core body 1 is formed by winding a metallized film, and the protective cover 2 is made of an insulating film. The protective cover 2 is wrapped around the outside of the core body, and the longitudinal direction of the insulating film is the same as the longitudinal direction of the metallized film; the ratio of the transverse heat shrinkage rate of the metallized film to the transverse heat shrinkage rate of the insulating film is 1:(0.85-1.05), and the ratio of the longitudinal heat shrinkage rate of the metallized film to the longitudinal heat shrinkage rate of the insulating film is 1:(0.85-1.05).

[0024] In the capacitor core provided by the present invention, the transverse and longitudinal heat shrinkage rates of the metallized film used to prepare the capacitor core body 1 and the insulating film used to prepare the protective cover 2 (outer film) are relatively close. The ratio of the transverse heat shrinkage rate of the metallized film to the transverse heat shrinkage rate of the insulating film is 1:(0.85-1.05), and the ratio of the longitudinal heat shrinkage rate of the metallized film to the longitudinal heat shrinkage rate of the insulating film is 1:(0.85-1.05). Therefore, during the subsequent heat setting process of the capacitor core, the shrinkage degree of the capacitor core body 1 and the protective cover 2 is basically the same, thereby achieving a close fit between the protective cover 2 and the capacitor core body 1, preventing metal particles from penetrating into the gap between the protective cover 2 and the capacitor core body 1 during the gold spraying process, thereby reducing the possibility of abnormal explosion during the energization process, and being safer during subsequent use.

[0025] In some embodiments of the present invention, illustratively, the metallized film is a metallized polypropylene film; the thickness of the metallized polypropylene film is 8-10 μm; and the metal coating of the metallized polypropylene film is a zinc-aluminum alloy coating.

[0026] In some embodiments of the present invention, illustratively, the insulating film is a single-sided roughened polypropylene film, and the thickness of the single-sided roughened polypropylene film is 14-16 μm.

[0027] In some embodiments of the present invention, illustratively, the insulating film is a double-sided roughened polypropylene film; the thickness of the double-sided roughened polypropylene film is 12-15 μm.

[0028] The embodiment of the present invention further provides a metallized film wound flattened capacitor, comprising the capacitor core described above. The capacitor provided by the embodiment of the present invention is safer during subsequent use.

[0029] An embodiment of the present invention further provides an electronic product including the metallized film wound flattened capacitor described above.

[0030] The present invention is further described below with reference to specific embodiments. For example, a metallized film specification of 9μm*75mm*3mm indicates a film thickness of 9μm, a width of 75mm, and a margin width of 3mm; an insulating film specification of 15μm*75mm indicates a film thickness of 15μm and a width of 75mm.

[0031] Example 1

[0032] A1. A capacitor core body is obtained by winding a metallized film as a raw material, and a protective cover made of an insulating film is provided on the outside of the capacitor core body so that the longitudinal direction of the insulating film is the same as that of the metallized film, and the capacitor core body is obtained. Figure 1 The capacitor core shown in the figure; wherein, the metallized film is a zinc-aluminum composite metallized polypropylene film with a specification of 9μm*75mm*3mm produced by Nantong Johnson Electronic Technology Co., Ltd., and after testing, the transverse heat shrinkage rate of the zinc-aluminum composite metallized polypropylene film is 1.542%, and the longitudinal heat shrinkage rate is 0.356%; the insulating film is an RP outer film with a specification of 15*75μm produced by Nantong Johnson Electronic Technology Co., Ltd., and the RP outer film is a single-sided roughened polypropylene film. After testing, the transverse heat shrinkage rate of the RP outer film is 1.357%, and the longitudinal heat shrinkage rate is 0.322%; the ratio of the transverse heat shrinkage rate of the zinc-aluminum composite metallized polypropylene film to the RP outer film is 1:0.880, and the ratio of the longitudinal heat shrinkage rate is 1:0.904.

[0033] A2. Flatten the capacitor core by hot pressing, and then perform heat setting and gold spraying to obtain a capacitor core to be tested.

[0034] Example 2

[0035] The difference from Example 1 is that in step A1, the insulating film is an RRP outer film with a specification of 12*75μm produced by Nantong Johnson Electronic Technology Co., Ltd., and the RRP outer film is a double-sided roughened polypropylene film. After testing, the transverse heat shrinkage rate of the RRP outer film is 1.453%, and the longitudinal heat shrinkage rate is 0.327%; the transverse heat shrinkage rate ratio of the zinc-aluminum composite metallized polypropylene film to the RP outer film is 1:0.942, and the longitudinal heat shrinkage rate ratio is 1:0.918.

[0036] Example 3

[0037] The difference from Example 1 is that in step A1, the insulating film is a RRP outer film with a specification of 15*75μm produced by Nantong Johnson Electronic Technology Co., Ltd., and the RRP outer film is a double-sided roughened polypropylene film. After testing, the transverse heat shrinkage rate of the RRP outer film is 1.537%, and the longitudinal heat shrinkage rate is 0.359%; the transverse heat shrinkage rate ratio of the zinc-aluminum composite metallized polypropylene film to the RRP outer film is 1:0.996, and the longitudinal heat shrinkage rate ratio is 1:1.008.

[0038] Comparative Example 1

[0039] The difference from Example 1 is that in step A1, the insulating film is a packaging film with a specification of 19*75μm produced by Nantong Johnson Electronic Technology Co., Ltd., and the packaging film is a polypropylene film without surface roughening. After testing, the transverse heat shrinkage rate of the packaging film is 1.893%, and the longitudinal heat shrinkage rate is 0.773%; the ratio of the transverse heat shrinkage rate of the zinc-aluminum composite metallized polypropylene film to the packaging film is 1:1.227, and the ratio of the longitudinal heat shrinkage rate is 1:2.171.

[0040] Experimental example

[0041] 200 capacitor cores to be tested were prepared using the processes in Examples 1-3 and Comparative Example 1, respectively. Then, an energizing test was performed and the number of unqualified products (explosion occurred) was counted. The results are shown in Table 1. 10 samples were taken from the samples that passed the energizing test in Examples 1-3 and Comparative Example 1 to form a capacitor core group. The capacitor core group was subjected to an aging test. The results are shown in Table 1. It can be seen from Table 1 that the defective rate of the capacitor cores to be tested prepared in Examples 1-3 was low during the energizing process. Among them, the defective rate of the capacitor core to be tested prepared in Example 3 was 0 during the energizing process, while the defective rate of the capacitor core to be tested prepared in Comparative Example 1 was 26.5%. It can be seen from Table 1 that the capacitor core groups in Examples 1-3 all passed the aging test, while the capacitor core group in Comparative Example 1 failed the aging test (creeping or explosion occurred during the aging process), indicating that the capacitor cores prepared in Examples 1-3 are safer in subsequent use.

[0042] Table 1

[0043]

[0044] 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 capacitor core, characterized in that: The invention comprises a capacitor core body (1) and a protective cover (2), wherein the capacitor core body (1) is wound by a metallized film, and the protective cover (2) is made of an insulating film. The protective cover (2) is wrapped around the outer side of the core body, and the longitudinal direction of the insulating film is the same as the longitudinal direction of the metallized film; the ratio of the transverse heat shrinkage rate of the metallized film to the transverse heat shrinkage rate of the insulating film is 1:(0.85-1.05), and the ratio of the longitudinal heat shrinkage rate of the metallized film to the longitudinal heat shrinkage rate of the insulating film is 1:(0.85-1.05); the metallized film and the insulating film are both stored or used in the form of a roll, and after unfolding the unused roll of film, the film is rectangular, with the longitudinal direction of the film being the longitudinal direction and the width direction being the longitudinal direction; the transverse heat shrinkage rate and the longitudinal heat shrinkage rate are the transverse heat shrinkage rate and the longitudinal heat shrinkage rate of the film at 100°C, respectively.

2. The capacitor core according to claim 1, characterized in that The metallized film is a metallized polypropylene film.

3. The capacitor core according to claim 2, characterized in that The metal coating of the metallized polypropylene film is a zinc-aluminum alloy coating.

4. The capacitor core according to claim 3, characterized in that The thickness of the metallized polypropylene film is 8-10 μm.

5. The capacitor core according to claim 1, characterized in that The insulating film is a single-sided roughened polypropylene film.

6. The capacitor core according to claim 5, characterized in that The thickness of the single-sided roughened polypropylene film is 14-16 μm.

7. The capacitor core according to claim 1, characterized in that The insulating film is a double-sided roughened polypropylene film.

8. The capacitor core according to claim 7, characterized in that The thickness of the double-sided roughened polypropylene film is 12-15 μm.

9. A metallized film wound flattened capacitor, characterized in that: The capacitor core comprises the capacitor core according to any one of claims 1 to 8.

10. An electronic product, characterized in that: The invention comprises the metallized film wound flattened capacitor as claimed in claim 9.

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