JP2000058369A - Film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an film capacitor without encapsulation which can prevent crackings of external electrodes of the capacitor due to external stress or mechanical stress, after being fixedly mounted on a substrate to provide superior electrical connection reliability. SOLUTION: A capacitor element 6A includes a metallized plastic film element 3, first metallikon layers 8 and 9 which form first external electrodes 12 as provided on both end faces 7 of the element 3 and which contain 70% or more of aluminum alloy and 4% or more of Is, second metallikon layers 10 and 11 of Sn alloy formed on the first layers, and plate-like terminals 13A which are fittingly and integrally bonded onto the capacitor element 6A to form second external plate-like terminal electrodes 13. Through this, a high electrical connection reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exterior-less film capacitor, and more particularly to a structure of an external plate-like terminal electrode integrally joined on a capacitor element.

[0002]

2. Description of the Related Art In recent years, with the rapid development and development of advanced packaging technologies in various electronic devices, small, flexible and highly reliable electrical connections are required for film capacitors. Have been. Hereinafter, a conventional manufacturing process will be described with reference to FIGS.

[0003] First, as shown in FIG.
A metal thin film is formed by vapor-depositing aluminum on the metal element, and the metal thin film is used as an internal electrode 36 to form a metal thin film. By turning, a first layer 28 made of a Zn alloy metallikon is formed on both end faces 27, a second layer 29 made of a solder alloy metallikon is formed on the first layer 28, and Ni plating is formed on the second layer 29. To form a third layer 30.
A capacitor element 26 having a structure in which a fourth layer 31 is formed by applying solder plating thereon to form an external terminal electrode 39 of the film capacitor can be formed, and a film capacitor 40 according to the prior art is obtained.

As shown in FIG. 12, a film capacitor 40 is attached to a land 33 on a printed circuit board 34.
Is mounted and fixed, and the external terminal electrode 39 of the capacitor 40 is fixed.
And the lands 33 are formed by soldering, and the electrode is peeled off at the interface between the first layer 28 and the fourth layer 31 of the external terminal electrode 39 due to mechanical stress such as substrate deflection during substrate division or attachment. This is a film capacitor 40 according to the related art, which has a disadvantage that (cracks) 35 are generated and may be generated mainly at the interface between the second layer 29 and the third layer 30.

[0005]

However, in the above-described film capacitor 40 according to the prior art,
A mechanical stress (deflection) is applied to the external terminal electrode 39 from the outside, and cracks 35 are generated in the range from the first layer 28 to the fourth layer 31. However, mainly the solder alloy metallikon 29 of the second layer and the third layer Occurs at the interface between the nickel plating 30 and the capacitance decrease (see FIG. 13) and the dielectric loss tangent (tan).
δ) Increase (see FIG. 14), electrical connection deterioration, cracks also increase (see FIG. 15), tan δ value increases, heat is generated when high frequency is applied, and thermal runaway is caused, eventually resulting in short circuit failure (The board bending resistance test of the conventional product; JIS C 51028.1.)
1.1: See FIGS. 13, 14 and 15 for reference. ).

An object of the present invention is to deform the plate-like terminal 13A constituting the second external plate-like terminal electrode 13 in response to external mechanical stress, thereby enabling cracks in the second external plate-like terminal electrode 13 and cracking. An object of the present invention is to provide a film capacitor 23 which prevents electrical characteristics from deteriorating and has more excellent connection reliability.

[0007]

According to the present invention, in order to achieve the above-mentioned object, a metallized plastic film 3 in which a metal thin film obtained from aluminum 4 is laminated on a plastic film 1 as an internal electrode 2 is laminated. The metallized plastic film element 6 is formed by wrapping the outer plastic film 5 thereover to form a metallized plastic film element 6. On both end faces 7 of the metallized plastic film element 6, a first metallikon layer 8 and a second metallikon layer 10 are formed. 11 is a film capacitor comprising a second external plate-like terminal electrode 13 on the capacitor element 6A which can be provided with the first external electrode 12 comprising the first external electrode 12. Metallicon layers 8 and 9 are made of 70% aluminum alloy.
% Or more, and a metallikon layer containing 4% or more of Si may be provided.
The capacitor element 6A, which constitutes the first external electrode 12 by providing a metallikon layer containing the remaining Zn and Cu, comprises a plate-like terminal 13A which is fitted onto the capacitor element 6A and integrally joined. The second external plate-shaped terminal electrode 13 is formed, and the opening 14 of the plate-shaped terminal 13A is formed.
A film capacitor 23 provided with plate-like terminals 15 and 16 around a welded portion 17 that can be deformed in response to external stress in a range between A and an opening 14B.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor in which a metallized plastic film 3 is wrapped and wound, an outer plastic film 5 is wrapped and wound thereon, and a first external electrode 12 is provided on both end surfaces 7. A plate-like terminal 13 is provided on the element 6A.
A, a film capacitor 23 provided with a second external plate-shaped terminal electrode 13 having a structure in which the second external plate-shaped terminal electrode 13 is fitted and integrally joined.
Wherein the metallized plastic film 3 is made of PP
A metal thin film is formed on S (polyphenylene sulfide), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or the like using aluminum.
The exterior plastic film 5 uses PPS.

Next, the first external electrode 12 is formed on the first metallikon layers 8 and 9 by the second metallikon layers 10 and 11.
The first metallikon layers 8 and 9 are formed of an alloy containing 70% or more of an aluminum alloy and 4% or more of Si, and electrically connect with the metal thin film of aluminum forming the internal electrode 2. Connection is optimal.

When the content of aluminum alloy is less than 70%, S
If i is less than 4%, it is not suitable because the adhesion strength may be reduced due to the shortage of each member material.

The second metallikon layers 10 and 11
Is composed of 80% or more of Sn and the remaining Cu and Zn.
Metallicon layers 10 and 1 on the first metallikon layers 8 and 9 by electric metallikon.
1 is formed.

If the content of Sn is less than 80%, the Sn metallikon layers 10 and 11 are deteriorated, and the adhesion strength to the plate-like terminal 13A is reduced.

Next, the second external plate-like terminal electrode 13
The material is SPCC (Fe thin plate) hardness HV120 and plate thickness is 0.
In the range of 09 to 0.13 mm
μ, Sn9: A plate-like terminal 13A made of electroplated Pd1 and having a thickness of 3 μm or less is fitted on the capacitor element 6A to form a gap between the welding electrodes 20A and 20B of 1.2 mm and a welding pressure of 1.5 kgf. (0.75 kg per side)
The spot welding 17 is performed.

In order to deform and cope with external stress or mechanical stress, the plate-like terminals 15 and 16 around the welded portion 17 existing in the area between the openings 14A and 14B are formed. The second external plate-like terminal bent portions 18 and 19 which are bent toward the central portion in the longitudinal direction of the capacitor element 6A and can be deformed to suppress external stress in the vertical direction, and in the longitudinal direction of the capacitor element 6A. The film capacitor 40 according to the prior art is provided with plate-like terminals 15A, 15B, 16A, 16B and the like between the soldered portion 21 and the spot welded portion 17 of the substrate 22 which can be deformed to suppress expansion or contraction. Degradation of electrical connection reliability, which has been a problem in
See FIG. 14 and FIG. ) Is prevented, and a higher film capacitor 23 is invented.

[0015]

Next, an embodiment of the present invention will be described with reference to FIGS.
FIGS. 4, 5, 6, 7 (a) and 7 (b), and 8 (a) to
(B), FIG. 9, FIG. 10, FIG. 16, FIG. 17, FIG.

(Example 1) As shown in FIG. 2, a metal thin film is formed by evaporating a metal with aluminum 4 on a plastic film 1 and a metallized plastic film 3 having the metal thin film as an internal electrode 2 is used. After the metallized plastic film 3 is wrapped and wound, and the outer plastic film 5 is wrapped and wound thereon to form a metallized plastic film element 6, an electric metallikon is used for both end faces 7 of the metallized plastic film element 6. , First metallikon layers 8 and 9 are formed, and second metallikon layers 10 and 9 are formed thereon.
And 11 are formed to form the first external electrode 12 to obtain the capacitor element 6A.

The plastic film 1 is, for example, polyphenylene sulfide (PPS),
Polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or the like may be used, but in this embodiment, polyphenylene sulfide (PPS) is suitable.

The first metallikon layers 8 and 9 are made of a metal containing 70% or more of an aluminum alloy and 4% or more of Si, and the second metallikon layers 10 and 11 are made of a Sn alloy with 80% or more of Sn remaining. It is made of a metal containing Zn and Cu.

Next, in forming the first metallikon layers 8 and 9, the metallized plastic film element 6 was formed by an electric arc spraying method using a wire rod diameter of 1.2 mmφ.
It is preferable that the thickness be in the range of 110 to 130 [mu] m on both end faces 7 of the substrate, but it is most preferable that the thickness be 120 [mu] m.

The electric arc spraying conditions include, for example, an applied voltage of 19 to 21V. D. C range, spray pressure air pressure range 4.5-5.5 kg / square centimeter, flow rate range 1.55-1.65 cubic meters / min, wire feed range 45-55 mm / sec, electrospray Distance in the range of 190-210mm, spraying speed 45-55mm
/ S range.

On the first metallikon layers 8 and 9, at least 80% of Sn, made of a Sn alloy, is Zn, Cu, Sb.
Use a wire rod diameter of 1.6mmφ including
The second metallikon layers 10 and 11 are formed in a range of μm.

The electric arc spraying conditions for forming the second metallikon layers 10 and 11 are, for example, different from the case of forming the first metallikon layers 8 and 9 in wire diameter and feed. At a wire speed of 1.6 mmφ and a feed rate of 35 mm / sec, in the second electric arc process, the wire speed was 1.6 mm.
The feed is 55 mm / sec in mmφ.

Next, the second metallikon layers 10 and 11
Is formed, after removing excess metallikon, 80V, 1 μm thickness of DC / film 3 is applied to capacitor element 6A for processing for 1 second. After the voltage treatment, the capacitor element 6A is immersed in epoxy and immersed in vacuum for impregnation, and after removing excess epoxy resin, is temporarily cured by heating at a temperature of about 120 ° C. for about 3 hours and then fully cured. Thereafter, the surfaces of the second metallikon layers 10 and 11 are cut and polished flat.

Then, as shown in FIG. 3, a plate-like terminal 13A having openings 14A and 14B is fitted on the surface of the first external electrode 12 of the capacitor element 6A, and is fitted between the welding electrodes 20A and 20B. About 1.2m
m, with a welding pressure of 1.5 kgf (0.75 kg on one side), spot welding 17 is performed to form the second external plate-like terminal electrode 13, and the opening is formed to suppress external stress and mechanical stress. Plate terminals 15 and 16 around the spot weld 17 existing in the area between the portion 14A and the opening 14B, the second outer plate terminal bent portions 18 and 19, the soldered portion of the substrate 22, and the spot weld. Plate terminals 15A and 15B between
The film capacitor 23 of the present invention constituting 16A, 16B and the like.

Next, as shown in FIG. 4, the plate-like terminals 13A are fitted on the surfaces of both first external electrodes 12 of the capacitor element 6A and integrally joined, thereby reducing external stress and mechanical stress. The plate-like terminals 15A and 1 between the plate-like terminals 15 and 16 around the welded portion 17 and the soldered portion 21 of the substrate and the spot welded portion 7 can be used, and have excellent electrical connection reliability.
This is a film capacitor 23 including 5B, 16A, 16B and second plate-shaped bent portions 18 and 19.

Next, as shown in FIG. 5, the plate-like terminal 13A is fitted to the capacitor element 6A having the first external electrode 12, so that the gap between the welding electrodes 20A and 20B is about 1.2 mm. After the setting, the welded portion 17 is spot-welded with a pressing force of 1.5 kgf (0.75 kg on one side).

Next, as shown in FIG. 6, it is a front view of the plate-like terminal 13A of this embodiment.
(Fe thin plate), plate thickness: about 0.11 mm, surface treatment: base,
It is formed by electroplating copper, a thickness of about 2 μ or less, Sn9: Pd1, a thickness of about 3 μ or less, or the like.

The dimensions of the plate terminal 13A are, for example, as follows:
a: 8.4 mm, b: 6.0 mm, c: 4.3 mm, d: 2.
5 mm, e: 4.0 mm, f: 4.0 mm, g: 0.8 mm,
h: 0.8 mm, i: 1.2 mm, j: 1.2 mm, h: 0.
4 mm, I: 0.9 mm, m: 0.9 mm, etc., and a weld existing in the range between the openings 14A and 14B in order to suppress external stress and mechanical deflection (stress). 17 and the plate terminals 15A, 15B, 16 between the second external plate terminal bent portions 18 and 19, the soldered portion of the substrate 22 and the spot welded portion.
A.16B and the like.

Next, FIG. 7A shows the structure of the second external plate-like terminal electrode 13 and the capacitor element 6A.
7B is a structure in which a plate-like terminal 13A is fitted on the surface of the first external electrode 12 to form an integrated joint welded portion 17 by spot welding. It is a figure which shows the schematic cross section of.

Next, FIG. 8 (a) shows the plate-like terminal 1 around the spot weld 17 existing in the range between the openings 14A and 14B when external stress or the like is applied in the direction of the arrow.
5 and 16 suppress external stress, and the plate-like terminals 15A, 15B, 16A, and 16B between the soldered portion of the substrate 22 and the spot welded portions also suppress external stress (stress). And the second external plate-shaped terminal bent portions 18 and 19 which bend toward the central portion in the longitudinal direction of the capacitor element 6A and can be deformed to suppress external stress in the vertical direction. This is the film capacitor 23 to be used.

Next, as shown in FIG. 9, a schematic sectional view showing a state where the film capacitor 23 of this embodiment is mounted on the substrate 22 and the solder fillet 21 is formed.
The film capacitor 23 can withstand deflection, external stress, mechanical stress, and the like.

Next, as shown in FIG. 10, after the film capacitor 23 of the present embodiment is mounted on the substrate 22, external stress in the direction of the arrow, and the bending of the substrate 22 when the substrate 22 is set and the like are suppressed and stress is relaxed. The plate-like terminals 15A, 15B, 16A, 16A, between the plate-like terminals 15 and 16 around the welded portion 17, the second external plate-like terminal bent portions 18 and 19, the soldered portion 21 of the substrate 22 and the spot welded portion 17 are provided. 1
6B and the like.

Next, the film capacitor 2 of the present embodiment
3 (MMX-F, 2A-105K (7D13), N = 2
0, L = 10.2 mm) according to JIS. C. 51028.1
A substrate bending resistance test was performed according to 1.1. As a test method, a test film capacitor 23 was attached to a printed circuit board, and JIS. C. The substrate 22 is bent at a speed of 1 mm / sec by the method of 5102, and after reaching a prescribed amount of deflection, is maintained for 10 seconds or more, and has a capacitance and a dielectric loss tangent (tan δ).
Was measured, and the appearance (cracks) was further observed. The results of this test are shown in FIG.
0 to 0.9 mm), and FIG.
FIG. 18 shows the number of appearance defects (cracks) (bending amount: 0.0 to 9.0 mm) and the like.

As shown in the capacitance ratio (%) in FIG. 16, even when the substrate deflection (mm) reaches 9.0 mm, the capacitance does not decrease, and FIG. 17 shows the dielectric loss tangent (%). tan
δ), but the dielectric loss tangent (tan δ) does not increase even when the substrate deflection amount (mm) reaches 9.0 mm, and is constant. Further, FIG. 18 shows the number of appearance defects (cracks). (mm) reaches 9.0 mm, no cracks occur, higher electrical characteristics are obtained than the conventional film capacitor 40, and a film capacitor 23 with excellent connection reliability can be realized. It has become.

[0035]

(1) According to the present invention, the first external electrode 1
2. a first metallikon layer 8 of aluminum (70% or more)
And 9 can be excellent in mechanical bonding with the internal electrode 2 and electrical characteristics, and the second external plate-like terminal electrode 13
By using the plate-like terminals 13A in the above structure, external stress and mechanical stress can be suppressed, and a film capacitor 23 with high electrical connection reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is a perspective view showing an embodiment of the present invention.

FIG. 4 is a schematic sectional view showing an embodiment of the present invention.

FIG. 5 is a schematic sectional view showing an external plate-shaped terminal electrode according to the embodiment of the present invention.

FIG. 6 is a front view showing an external plate terminal used in the embodiment of the present invention.

FIGS. 7A and 7B are schematic explanatory views showing an embodiment of the present invention.

8 (a) and 8 (b) are schematic cross-sectional views showing plate-like terminals exhibiting a function of suppressing stress when an external stress occurs in a binding direction in an embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view showing a state in which a film capacitor is mounted on a substrate in an embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view illustrating a case where a board-like terminal suppresses this bending when a substrate warp occurs after the film capacitor according to the embodiment of the present invention is mounted.

FIG. 11 is a sectional view showing a conventional example according to the conventional technique.

FIG. 12 is a schematic cross-sectional view showing a failure of electrode peeling in a conventional example according to a conventional technique.

FIG. 13 is a diagram showing a capacitance change rate (%) depending on a substrate deflection amount in a conventional example according to the conventional technology.

FIG. 14 is a diagram showing a dielectric loss tangent (tan δ) according to a conventional substrate deflection amount according to a conventional technique.

FIG. 15 is a diagram showing the number of appearance defects (cracks) based on the amount of substrate deflection in a conventional example according to the conventional technique.

FIG. 16 is a diagram showing a capacitance change rate (%) depending on the amount of substrate deflection in an example of the present invention.

FIG. 17 is a diagram showing a dielectric loss tangent (tan δ) depending on the amount of substrate deflection according to the example of the present invention.

FIG. 18 is a diagram showing the number of appearance defects (cracks) according to the amount of substrate deflection in the example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plastic film 2 ... Internal electrode 3 ... Metalized plastic film 4 ... Aluminum 5 ... Outer plastic film 6 ... Metalized plastic film element 6A ... Capacitor element 7 ... End face 8,9 ... First metallikon layer 10,11 ... Second Metallicon layer 12 First external electrode 13 Second external plate-like terminal electrode 13
A: Plate-shaped terminals 14A, 14B: Openings 15, 16 ... Plate-shaped terminals around welded parts 15A, 15B, 16A, 16B: Plate-shaped terminals between soldered parts and spot-welded parts 17: Spot-welded parts 18, 19 ... Bending portions of second outer plate-shaped terminals 20A, 20B ... Welding electrodes 21 ... Solder fillets 22 ... Substrates (including lands) 23 ... Film capacitors of the present invention 24 ... Plastic films 24A ... Plastic elements 25 ... Exterior plastic films 26 ... Capacitors Element 27 ... End face 28 ... First layer zinc alloy metallikon layer 29 ... Second layer solder alloy metallikon layer 30 ... Third layer nickel plating 31 ... Fourth layer solder plating 32 ... Solder fillet
Reference Signs List 33 land 34 substrate 35 exfoliation (crack) 36 internal electrode 37 metallized plastic film 38 aluminum 39 external electrode 40 film capacitor according to prior art Reference number p2463

Continuing from the front page (72) Inventor Takao Yoshiwara F-term (reference) 5E082 AA01 AB05 BC33 EE07 EE24 EE37 FF05 FG06 FG34 FG48 GG08 GG10 GG11 GG22 GG27 JJ07 JJ22 JJ25 PP03

Claims (4)

[Claims] 1. A metallized plastic film (3) obtained by laminating a metal thin film obtained from aluminum (4) on a plastic film (1) as an internal electrode (2) is wound around the plastic film (1). ) To form a metallized plastic film element (6) by lap winding, and a metallized plastic film element (6), on both end faces 7 of the metallized plastic film element (6), and on the first metallikon layers (8) and (9) Capacitor element (6A) provided with first external electrode (12) comprising (10) and (11)
Wherein the first metallikon layers (8) and (9) comprise a second external plate-shaped terminal electrode (13) on the capacitor element (6A).
A metallikon layer containing 70% or more of an aluminum alloy and 4% or more of Si may be provided, and the second metallikon layers (10) and (11) may be provided with a metallikon layer containing 80% or more of a Sn alloy and remaining Zn and Cu. With the capacitor element (6A) that constitutes the first external electrode (12),
The second external plate-shaped terminal electrode (13) is formed of a plate-shaped terminal (13A) fitted and integrally joined on the capacitor element (6A), and an opening of the plate-shaped terminal (13A) is formed. A film capacitor provided with plate-like terminals (15) and (16) around a welded portion (17) capable of deforming in response to external stress in a range between (14A) and the opening (14B). (23). 2. The welded part (17) according to claim 1, wherein the soldered part (17) is located between the openings (14A) and (14B) at a position parallel to the soldered part by the resistance welding. A film capacitor (2) characterized in that the surrounding plate-like terminals (15) and (16) have a shape of a plate-like terminal (13A) that can be deformed in response to external stress.
3). 3. The terminal according to claim 1, wherein both ends of the plate-like terminal (13A) serving as the second external plate-like terminal electrode (13) are bent toward the center in the longitudinal direction of the capacitor element (6A). Thus, the second external plate-shaped terminal bent portions (18) and (19) are formed to have a shape of the plate-shaped terminal (13A) that can be deformed in response to external stress in the upward and downward directions. Characteristic film capacitor (23). 4. A plate-like terminal (15A), (15B), (16A), (16B) between a soldered portion (21) of the substrate (22) and a spot welded portion (17).
A film capacitor (23) having a shape of a plate-like terminal (13A) that can be deformed in response to expansion or contraction in the longitudinal direction of the capacitor element (6A).