CN109817463B

CN109817463B - Electrolytic capacitor

Info

Publication number: CN109817463B
Application number: CN201910197556.7A
Authority: CN
Inventors: 欧紫娟
Original assignee: Quanzhou Quanshi Electronic Technology Co ltd
Current assignee: Quanzhou Quanshi Electronic Technology Co ltd
Priority date: 2019-03-15
Filing date: 2019-03-15
Publication date: 2024-02-13
Anticipated expiration: 2039-03-15
Also published as: CN109817463A

Abstract

The invention relates to the technical field of capacitors, and discloses an electrolytic capacitor which can slow down the decay speed of an oxide film and has good frequency characteristics and greatly enhanced current capacity, wherein the electrolytic capacitor is provided with at least one layer of anode foil and at least one layer of cathode foil, anode lead wires are arranged on any side of the anode foil, cathode lead wires are arranged on any side of the cathode foil, at least one layer of isolation layer is arranged between the at least one layer of cathode foil and the at least one layer of anode foil, at least one layer of cathode foil, at least one layer of isolation layer and at least one layer of anode foil are laminated to form a laminated unit, and an internal core of the electrolytic capacitor comprises 3 to 85 laminated units.

Description

Electrolytic capacitor

Technical Field

The invention relates to the technical field of capacitors, in particular to an electrolytic capacitor.

Background

Electrolytic capacitors are common electronic components in medium frequency and low frequency circuits, and have the functions of filtering, signal coupling, blocking and the like. In the past, electrolytic capacitor's pin area is little and the power is less, is unfavorable for heavy current charge and discharge, and output waveform distortion is comparatively serious.

Therefore, the electrolytic capacitor with small volume, large pin area and large capacity is provided in the prior art, and the defect of waveform distortion output when the electrolytic capacitor is used in a high-power circuit is effectively overcome. However, the conventional electrolytic capacitor has a large Equivalent Series Resistance (ESR) and poor frequency characteristics, and in the long-term use, the leakage current decreases and the capacitance decreases, and the water in the electrolyte is evaporated to increase the viscosity of the electrolyte due to heat generation of the capacitor, and the series resistance increases to extremely increase the loss tan δ, which results in failure of the electrolytic capacitor.

Disclosure of Invention

The invention aims to provide a laminated electrolytic capacitor which has a good frequency characteristic and greatly enhanced current passing capability and can reduce the aging speed of a heating delay oxide film and an electrolyte.

The technical scheme adopted for solving the technical problems is as follows: an electrolytic capacitor is constructed having at least one anode foil and at least one cathode foil, anode lead bars are provided on either side of the anode foil, cathode lead bars are provided on either side of the cathode foil, at least one separator is provided between the at least one cathode foil and the at least one anode foil, at least one cathode foil, at least one separator and at least one anode foil are laminated to form a laminated unit,

the electrolytic capacitor includes 3 to 85 of the laminated units.

Preferably, the laminated unit has one layer of the anode foil, one layer of the cathode foil, and one to six layers of the separator layers.

Preferably, the upper layer of the laminated unit is a separator paper layer, and the lower layer of the laminated unit is the anode foil or the cathode foil.

Preferably, the thickness of the anode foil is set at 30 to 500 micrometers, the thickness of the cathode foil is set at 10 to 500 micrometers, and the single-layer thickness of the separator layer is set at 1 to 500 micrometers.

Preferably, the laminated unit further comprises an additional multi-layer consisting of a sheet with or without a lead strip.

Preferably, the additional layers are provided inside or outside the laminated unit.

Preferably, the foil may be composed of the anode foil, the cathode foil and the separator layer, or of other types of conductive metal or non-conductive non-metallic material, the thickness of the foil being 0.1 micrometers to 5 millimeters.

Preferably, the electrolytic capacitor specifically includes 3 to 85 sheets of the anode foil, 3 to 85 sheets of the cathode foil, and 3 to 525 sheets of the separator, and the lowermost and uppermost layers of each of the laminated units are the cathode foil, the anode foil, or the separator, and the number of the anode lead bars and the cathode lead bars is set to 3 to 85 pairs.

Preferably, at least one layer of the sheet or insulator is between the core outer layer and the casing after the lamination of the lamination unit, the sheet being the cathode foil, the separator layer or the additional layers to prevent the anode foil from shorting to contact with the casing.

Preferably, the electrolytic capacitor further includes a case having an accommodation space formed therein, and the plurality of laminated units are laminated and then accommodated in the case.

Preferably, the separator partially covers the cathode foil, forming a laminated structure exposing the cathode, and the exposed portion of the cathode foil is in contact with the case.

Preferably, the separator entirely covers the cathode foil, and is formed in a laminated structure without exposing the cathode, and the exposed portion of the separator is in contact with the case.

In the electrolytic capacitor provided by the invention, the cathode foil, the isolation layer, the anode foil and the isolation layer are laminated in sequence or the isolation layer, the cathode foil, the isolation layer and the anode foil are laminated in sequence to form a laminated unit. And stacking a plurality of stacked units together to form a stacked core of the capacitor, wherein an isolating layer is arranged between the cathode foil and the anode foil, so that the mutual contact between the cathode foil and the anode foil can be restrained, and the short circuit resistance of the electrolytic capacitor is effectively improved. In addition, the stacked core is immersed in an electrolyte containing a conductive ion or a conductive polymer. Conductive layers are formed on the inner and outer surfaces of the stacked cores, reducing the interfacial resistance between the cathode foil and the conductive polymer. Compared with the conventional electrolytic capacitor, the invention reduces ESR and tan delta, and improves the frequency response speed and the current passing capability of the electrolytic capacitor.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic view of a part of the structure of an electrolytic capacitor;

FIG. 2 is a schematic view of a structure of a first electrolytic capacitor;

FIG. 3 is a schematic view of a structure of a second electrolytic capacitor;

FIG. 4 is a schematic view of a structure of a third electrolytic capacitor;

fig. 5 is another view structural schematic diagram of the first electrolytic capacitor;

FIG. 6 is another view of a schematic structural diagram of a second stacked electrolytic capacitor;

FIG. 7 is a cross-sectional view of an electrolytic capacitor;

FIG. 8 is a partial enlarged view of a sectional view of an electrolytic capacitor;

FIG. 9 is another partial enlarged view of a sectional view of an electrolytic capacitor;

FIG. 10a is an enlarged schematic view of the inner core of an electrolytic capacitor;

fig. 10b is a schematic view of a structure in which the lamination unit is laminated upward;

fig. 10c is a schematic view of a structure in which the lamination unit is laminated downward;

FIG. 11 is a schematic view of a first construction of an anode foil and an anode lead strip;

FIG. 12 is a schematic view of a second construction of an anode foil and anode lead wire;

fig. 13 is a schematic view of a third structure of an anode foil and an anode lead wire.

Detailed Description

For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings.

The structure of the electrolytic capacitor will be described below. Fig. 1 is a schematic view of a part of the structure of an electrolytic capacitor. As shown in fig. 1, the present embodiment provides a laminated electrolytic capacitor having a hollow case 1 formed with an accommodating space, in which a multilayer anode foil 2, a multilayer cathode foil 3, and a multilayer separator 4 can be accommodated in the case 1. In the present invention, a concept of a laminated unit is defined, and the laminated unit includes at least one cathode foil, at least one separator layer, and at least one anode foil layer, and they are configured as a laminated structure, and thus are called a laminated unit. Specifically, the cathode foil 3, the separator 4, the anode foil 2 and the separator 4 may be laminated in this order, or the separator 4, the cathode foil 3, the separator 4 and the anode foil 2 may be laminated in this order, or the separator 4, the anode foil 2, the separator 4 and the cathode foil 3 may be laminated in this order, and the lamination method is not limited thereto.

In the present invention, an electrolytic capacitor is formed by laminating a plurality of laminated units. Although a plurality of laminated units are referred to herein, the laminated units are not independent but are connected to each other. More precisely, the anode foils 2 of the respective laminated units are interconnected, as are the cathode foils 3 of the respective laminated units.

Further, an anode lead line 5 is provided at either end of the anode foil 2, and a cathode lead line 6 is provided at either end of the cathode foil 3.

Fig. 2 is a schematic view of the structure of the first electrolytic capacitor. As shown in fig. 2, the outer casing 1 has a square outer appearance, and the anode lead 5 and the cathode lead 6 are disposed on the same end face.

Fig. 3 is a schematic view of a structure of a second electrolytic capacitor. As shown in fig. 3, the outer casing 1 has a square shape in appearance, and the anode lead 5 and the cathode lead 6 are disposed on opposite sides of the outer casing 1. Specifically, the anode lead 5 and the cathode lead 6 are arranged on the same axis perpendicular to the surface of the case 1.

Fig. 4 is a schematic structural view of a third electrolytic capacitor. As shown in fig. 4, the appearance of the housing 1 is a square structure, the anode lead bar 5 and the cathode lead bar 6 are not on the same end face, specifically, the anode lead bar 5 and the cathode lead bar 6 are disposed at two opposite ends of the housing 1, and the pins are irregularly disposed.

Fig. 5 is another view of the structure of the first electrolytic capacitor. As shown in fig. 5, the anode lead 5 and the cathode lead 6 of the electrolytic capacitor are disposed on the same end face, which is consistent with the structure shown in fig. 2. Further, a cross-shaped explosion-proof valve 11 is provided on the surface of the housing 1, and the position where the explosion-proof valve 11 is provided is not limited, and may be at the bottom or on both sides. When the internal pressure of the capacitor is too high, the shell 1 of the capacitor can be cracked at the explosion-proof valve 11 to release the redundant pressure, so that the generation of excessively strong explosion is avoided.

Fig. 6 is another view of a schematic structural diagram of a second electrolytic capacitor. As shown in fig. 6, the surface of the electrolytic capacitor case 1 is provided with a Y-shaped explosion-proof valve 11', and the function of the explosion-proof valve 11' is identical to that of the explosion-proof valve 11. Further, the anode lead 5 and the cathode lead 6 are not on the same end face and the anode lead 5 and the cathode lead 6 are on the same axis, which is consistent with the structure type shown in fig. 3.

Fig. 7 is a sectional view of an electrolytic capacitor. As shown in fig. 7, the cross-sectional view is cut longitudinally along the line E-F shown in fig. 5 or 6, and the cut surface E-F is enlarged at a selected position, and the enlarged portion is an enlarged portion 12.

Fig. 8 is a partial enlarged view of a sectional view of the electrolytic capacitor, and fig. 9 is another partial enlarged view of a sectional view of the electrolytic capacitor. Fig. 8 shows a schematic cross-sectional view of fig. 5, and fig. 9 shows a schematic cross-sectional view of fig. 6. As shown in fig. 8 and 9, the housing 1 is molded with a metal material 9. The case 1 has a structure in which a plurality of laminated units are provided inside. As described above, the lamination unit has a plurality of possible lamination modes, for example, but not limited to, as follows:

1. the isolating layer 4, the cathode foil 3, the isolating layer 4, the anode foil 2 and the isolating layer 4 are sequentially laminated to form a laminated unit;

2. the isolating layer 4, the cathode foil 3, the isolating layer 4, the anode foil 2, the isolating layer 4 and the energy storage invalid layer 10 are sequentially laminated to form a laminated unit, wherein the energy storage invalid layer 10 is formed by a foil, and no lead wire is arranged and is insulated relative to the anode foil 2 and the cathode foil 3;

3. the isolating layer 4, the cathode foil 3, the isolating layer 4, the energy storage ineffective layer 10, the isolating layer 4, the anode foil 2 and the isolating layer 4 are sequentially laminated to form a laminated unit;

4. the isolating layer 4, the two layers of cathode foils 3 are directly contacted and laminated, and the isolating layer 4, the anode foil 2 and the isolating layer 4 are sequentially laminated to form a laminated unit;

5. the isolating layer 4, the cathode foil 3 and the two isolating layers 4 are directly contacted and laminated, and the anode foil 2 and the isolating layers 4 are sequentially laminated to form a laminated unit;

6. the isolating layer 4, the two layers of cathode foils 3 are directly contacted and laminated, and the isolating layer 4, the anode foil 2 and the energy storage ineffective layer 10 are sequentially laminated to form a laminated unit;

7. the separator 4, the cathode foil 3, the two separator layers 4 are laminated in direct contact, the cathode foil 3, the separator layers 4, the energy storage invalid layer 10, the separator layers 4, the anode foil 2, the separator layers 4, and the energy storage invalid layer 10 are laminated in this order to form a laminated unit.

The plurality of lamination units are laminated to constitute the inner core 13. Preferably, the number of layers of the separator 4 is preferably one to three, more preferably two, in each laminated unit.

The lowermost layer of the inner core 13 is the separator layer 4, the cathode foil 3 or the energy storage inactive layer 10 but not the anode foil 2; correspondingly, the uppermost layer of the inner core 13 is likewise the separator layer 4, the energy storage inactive layer 10 or the cathode foil 3 but not the anode foil 2.

As described above, the energy storage inactive layer 10 may be formed between the anode foil 2 and the cathode foil 3, and the energy storage inactive layer 10 has an insulating function for improving the insulating effect inside the electrolytic capacitor. Specifically, the energy storage inactive layer 10 may be provided inside or outside the laminated unit structure. The energy storage inactive layer 10 has no lead, and is not connected to the anode lead of the anode foil 2 or the cathode lead of the cathode foil 3.

As described above, the cathode foil 3 may be two layers of the laminated separator layers 4 within each laminated unit, which can prevent the anode foil 2 and the cathode foil 3 from directly contacting each other, effectively improving the short circuit resistance of the capacitor.

The extent to which the cathode foil 3 is laminated may exceed or be the same as the area of the separator layer 4. The separator 4 completely covers the anode foil 2 or the separator 4 completely covers or partially covers the cathode foil 3, forming a laminate structure without exposing the cathode or exposing the cathode. Further, at least one side of the cathode foil 3 is exposed to the separator 4, thereby forming a cathode-exposed laminated structure. Preferably, the exposed portion of the cathode foil 3 is in contact with the inner wall of the case 1, so that heat dissipation inside the electrolytic capacitor can be accelerated.

Fig. 10a is an enlarged schematic view of the inner core of the electrolytic capacitor. As shown in fig. 10a, the cathode foil 3 or the separator 4 is laminated on top or bottom. Optionally, the inner core 13 includes 5 to 85 anode foils 2,5 to 85 cathode foils 3 and 5 to 85 isolating layers 4, and the lowest layer and the uppermost layer of the inner core 13 are the cathode foils 3 or the isolating layers 4, the number of the anode lead wires 5 and the cathode lead wires 6 is set between 5 to 85 pairs, further, the plurality of anode lead wires 5 and the cathode lead wires 6 need to be fixed respectively, and the fixing manner is various, for example, one half of the plurality of anode lead wires 5 (or the cathode lead wires 6) can be bound together, and then the other half of the anode lead wires 5 (or the cathode lead wires 6) are bound together; all the anode lead wires 5 (or the cathode lead wires 6) may be welded by welding or the like, and the fixing method is not limited.

Fig. 10b is a schematic view of the structure in which the lamination unit is laminated upward. As shown in fig. 10b, the lamination unit further has a lamination manner as follows: as indicated by the arrow J, the laminated structure is laminated from bottom to top, specifically, the cathode foil 3 with the largest width is laminated on the lower layer, the separator paper layer 15 is laminated on the upper surface of the cathode foil 3, the cathode foil 3 is directly laminated in contact with the separator paper layer 15, the anode foil 2 with the shorter width is laminated on the upper surface of the separator paper layer 15, the separator paper layer 15 is directly laminated in contact with the anode foil 2, and the cathode foil 3, the separator paper layer 15 and the anode foil 2 are alternately laminated in sequence. The cathode foil 3, the separator paper layer 15, the anode foil 2, the separator paper layer 15 and the cathode foil 3 constitute a laminated unit. Wherein the separator paper layer 15 is able to completely cover the anode foil 2, which serves as insulation in the laminated unit to prevent the anode foil 2 from being in direct contact with the housing 1, causing a short circuit.

Fig. 10c is a schematic view of a structure in which the lamination units are laminated downward. As shown in fig. 10c, the lamination unit further has a lamination manner as follows: as indicated by the arrow K, the laminated structure is laminated from top to bottom, specifically, the separator paper layer 15, the cathode foil 3, the separator paper layer 15, the anode foil 2, the separator paper layer 15, and the cathode foil 3 constitute one laminated unit. The separator paper layer 15 is in direct laminated contact with the cathode foil 3; the separator paper layer 15 is in direct laminated contact with the anode foil 2. Wherein the separator paper layer 15 can completely cover the anode foil 2. Wherein at least one layer of foil or insulation is provided between the outer layer of the inner core 13 and the outer shell 1. In particular, the foil may be a cathode foil 3, a separator 4 or an additional layer to prevent the anode foil 2 from being in direct contact with the housing 1, causing a short circuit.

Further, as shown in fig. 8 and 9, a fixing material 14 is disposed around the inner wall of the housing 1, where the fixing material 14 is selected from silica gel, APP gel, special adhesive tape (e.g. double sided tape), plastic sheet and elastic material. Specifically, a plurality of laminated units (i.e., the inner cores 13) are fixed by winding with the adhesive tape 8. The fixed inner core 13 is then placed into the housing 1, and the space in the housing 1 can be filled with silica gel or APP gel, thereby fixing the inner core 13 within the housing 1. It is also possible to wind a special adhesive tape around the surface of the inner core 13 and then press the inner core 13 into the housing 1, with the inner core 13 being closely adhered to the inner wall of the housing 1 by the special adhesive tape (e.g., double-sided adhesive tape). The inner core 13 may also be secured with a plastic sheet or an elastic material. Specifically, the plastic sheet may be wedged into the housing 1 or an elastic material (e.g., a pre-embedded wedge sheet) may be preset in the housing 1 so that a pressing moment is generated between the inner core 13 and the housing 1, thereby securing the inner core 13 in the housing 1.

Fig. 11 is a schematic view of a first structure of an anode foil and an anode lead wire. As shown in fig. 11, the cathode foil 3, the separator 4, and the anode foil 2 have a flat plate shape, which may be rectangular, rounded rectangular, or other shapes. The cathode lead 6 is connected to the cathode foil 3 as a single piece. The anode lead 5 is connected to the anode foil 2 as a single piece. The cathode foil 3 and the cathode lead 6 may be cut from one foil. Similarly, the anode foil 2 and the anode lead 5 may be cut from one foil. The lead bars formed in this way have no connection resistance at the lead bars, and therefore, the resistance between the lead bars connected to the respective electrode foils can be reduced.

Fig. 12 is a schematic view of a second structure of the anode foil and the anode lead wire. As shown in fig. 12, the anode foil 2 and the anode lead 5 are each separate, and one end surface of the anode foil 2 and the side surface of the anode lead 5 are connected to each other to form a joint 7, and butt welding is performed at the joint 7, whereby the waste of material can be reduced by this connection.

Fig. 13 is a schematic view of a third structure of an anode foil and an anode lead wire. As shown in fig. 13, the anode foil 2 and the anode lead 5 are separate units, the length of the anode lead 5 is reserved to be a part greater than that of the second connection mode, specifically, a part of the anode lead 5 is overlapped with the anode foil 2 to form an overlapped part 7', and the overlapped part 7' is overlapped and welded to connect the anode lead 5 and the anode foil 2, and the connection mode can improve the connection tightness of the anode lead 5 and the anode foil 2 and improve the mechanical fatigue resistance of the capacitor pin compared with the second connection mode.

The material of the electrolytic capacitor element will be described below. Fig. 9 illustrates a schematic cross-sectional view of the anode foil 2, the cathode foil 3 and the separator layer 4 (or the energy storage inactive layer 10). As shown in fig. 9, an electrically conductive electrolyte or polymer is provided between the cathode foil 3 and the separator 4 and between the anode foil 2 and the separator 4.

The anode foil 2 is formed of valve metal. Alternatively, the anode foil 2 may have a thickness between 30 and 150 micrometers. Preferably, the thickness of the anode foil 2 is set to 60 to 130 μm. The dielectric oxide layer is formed by etching and chemical oxide etching the surface of the anode foil 2. Further, in order to obtain an electrolytic capacitor having a large capacity and a small volume, a rugged surface is formed on the surface of the anode foil 2 by a chemical etching method, so that the surface area of the electrode is increased, and the capacitance is increased.

The cathode foil 3 may be made of aluminum or metal. In the present embodiment, the cathode foil 3 is formed of aluminum foil. Preferably, the thickness of the cathode foil 3 may be between 10 and 15 micrometers. The surface of the cathode foil 3 is subjected to a vapor deposition treatment or a physical adsorption treatment of carbide, and carbide particles are adsorbed onto the surface of the cathode foil 3.

The isolation layer 4 may be made of wood fiber, hemp fiber, rayon or the like. The separator 4 serves as a separator for adsorbing an electrolyte during the electrolytic production.

The dielectric is an aluminum oxide film or a tantalum pentoxide film. The anode foil 2 is corroded to form a very thin alumina film, and the electrolyte is required to continuously repair the alumina film or the tantalum pentoxide film when the electrolytic capacitor works, so that further oxidation of the anode foil 2 can be effectively prevented, and the loss of series resistance and tan delta is reduced. Further, the thickness of the aluminum oxide film or tantalum pentoxide film is set at 30 to 60 μm.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.

Claims

1. An electrolytic capacitor is characterized by comprising at least one anode foil and at least one cathode foil, wherein anode lead wires are arranged on any side of the anode foil, cathode lead wires are arranged on any side of the cathode foil, at least one isolation layer is arranged between the at least one cathode foil and the at least one anode foil, at least one cathode foil, at least one isolation layer and at least one anode foil are laminated to form a laminated unit,

the lamination unit further comprises an additional multi-layer consisting of a sheet with or without a lead bar;

the thin sheet is composed of the anode foil, the cathode foil and the isolating layer, or is composed of other types of conductive metal or non-conductive nonmetallic materials, and the thickness of the thin sheet is 0.1 micrometer to 5 millimeters;

the anode foil and the anode lead bar are independent individuals respectively; one end surface of the anode foil and the side surface of the anode lead wire are connected with each other to form a joint part, butt welding is carried out at the joint part, or part of the anode lead wire is overlapped with the anode foil to form an overlapped part, and the two parts are connected by lamination welding at the overlapped part;

the electrolytic capacitor includes 3 to 85 of the laminated units.

2. The electrolytic capacitor according to claim 1, wherein the laminated unit has one layer of the anode foil, one layer of the cathode foil, and one to six layers of the separator.

3. Electrolytic capacitor according to claim 1 or 2, characterized in that the upper layer of the laminated unit is a separator paper layer and the lower layer of the laminated unit is the anode foil or the cathode foil.

4. Electrolytic capacitor according to claim 1 or 2, characterized in that the anode foil has a thickness of 30 to 500 micrometers, the cathode foil has a thickness of 10 to 500 micrometers, and the separator has a single layer thickness of 1 to 500 micrometers.

5. The electrolytic capacitor according to claim 1, wherein the additional layers are provided inside or outside the laminated unit.

6. The electrolytic capacitor according to claim 1 or 2, wherein the electrolytic capacitor specifically comprises 3 to 85 sheets of the anode foil, 3 to 85 sheets of the cathode foil, and 3 to 525 sheets of the separator, and the lowermost layer and the uppermost layer of each of the laminated units are the cathode foil, the anode foil, or the separator, and the number of the anode lead bars and the cathode lead bars is set to 3 to 85 pairs.

7. The electrolytic capacitor according to claim 2, further comprising a case having an accommodation space formed therein, wherein a plurality of the laminated units are laminated and accommodated in the case.

8. The electrolytic capacitor according to claim 7, wherein at least one layer of the sheet or the insulator is provided between the core outer layer and the case after the lamination of the lamination unit, and the sheet is the cathode foil, the separator, or the additional layers to prevent the anode foil from shorting to the case.

9. The electrolytic capacitor according to claim 7, wherein the separator partially covers the cathode foil, forming a laminated structure exposing a cathode, the exposed portion of the cathode foil being in contact with the case.

10. The electrolytic capacitor according to claim 7, wherein the separator portion entirely covers the cathode foil, is formed in a laminated structure in which a cathode is not exposed, and is in contact with the case at an exposed portion thereof.