JP2009130338A - Connection method for tab terminal to aluminum electrode foil, aluminum electrolytic capacitor, and solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further reduce resistance by reliably connecting a tab terminal to electrode foil mechanically and electrically without performing any special machining to the tab terminal itself. <P>SOLUTION: A flat section 2b of the tab terminal is overlapped to aluminum electrode foil 4; a drill-like caulking needle is stuck from above the flat section 2b; a petal-like nib piece 10 projecting to the side of the aluminum electrode foil 4 is formed around the sticking hole 5a; the nib piece 10 is crimped to the aluminum electrode foil 4 by a prescribed tool; and further laser beams are applied to the crimped part of the nib piece 10 by a laser welding machine 11 for laser welding. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of connecting a tab terminal to an aluminum electrode foil, an aluminum electrolytic capacitor, and a solid electrolytic capacitor, and more specifically, by further improving the attachment of the tab terminal to the electrode foil, the resistance of the capacitor can be further reduced. It relates to measuring technology.

  An aluminum electrolytic capacitor is provided with a capacitor element formed by winding an anode electrode foil and a cathode electrode foil made of aluminum through separator paper, and each electrode foil has an electrode terminal for charging and discharging. Tab terminal is connected. In addition, an aluminum alloy foil or a vapor deposition foil obtained by vapor-depositing aluminum, titanium or the like may be used for each electrode foil.

  FIG. 4 shows a general connection example of the tab terminal to the electrode foil. According to this, the tab terminal 1 includes a terminal body 2 and a CP wire (solder-plated copper-coated steel wire) 3 attached to the terminal body 2.

  The terminal main body 2 uses a round bar wire of aluminum as a base material, leaves a round bar portion 2a of a predetermined length, and is integrally connected to one end of a flat portion (flat portion) 2b having a blade plate shape by, for example, pressing. The CP wire 3 is attached to the other end of the round bar portion 2a by welding.

  In many cases, the tab terminal 1 is attached to the electrode foil 4 by so-called “caulking”. “Caulking” refers to a technique in which the flat portion 2b is overlapped with the electrode foil 4 and fixed by caulking the caulking needle 5, but actually, after caulking the caulking needle 5, the area around the puncture hole The petal-like nail pieces formed on the surface are crushed by a press or the like.

  As an example, in the case of the tab terminal 1 applied to an aluminum electrolytic capacitor having an outer diameter of 5 mm in diameter, an axial length of 11 mm, and a width of the electrode foil 4 used of 6 mm, the terminal body 2 has a total length of 8.7 mm. The flat portion 2b has a length of 6.5 mm, a width of 1.5 mm, and a thickness of 0.25 mm, and has three caulking locations.

  As the caulking needle 5, for example, a needle having a diameter of 0.7 to 1.0 mm is used. When the caulking needle is caulked at three places, a peel strength of about 200 to 500 g · cm · f can be obtained. There is no.

  However, if the state in which the electrode foil 4 is held by the petal-like nail pieces during pressing is poor, the contact resistance increases, and in the worst case, there is a risk of a disconnection accident.

  In order to solve this point, in the invention described in Patent Document 1, as shown in FIG. 5, a thin plate portion 2c having a thickness smaller than that of the flat portion 2b is further provided integrally with the end portion of the flat portion 2b. In addition, the flat portion 2b is attached to the electrode foil 4 by caulking, and the thin plate portion 2c is attached to the electrode foil 4 by means of an intermetal coupling means (for example, a cold die 6).

JP-A-6-84711

  According to the invention described in Patent Document 1, the flat portion 2b is attached to the electrode foil 4 by caulking, and the thin plate portion 2c is attached to the electrode foil 4 by metal-to-metal bonding, for example, cold pressure welding. Both are improved.

  However, when the roughness of the electrode foil is high, or when the electrode foil is formed at a high voltage, it is difficult to make an electrical connection. Moreover, since the plate | board thickness of the thin plate part 2c is thin, it may be damaged, for example depending on the pressure applied at the time of cold pressure welding.

  Furthermore, since the width of the electrode foil 4 is gradually narrowed due to the recent demand for low profile (shortening of the axial length of the metal case), the length of the terminal body 2 is also shortened accordingly. There is no room for 2c itself. Further, as the length of the terminal body 2 is shortened, the number of places where the caulking needles are stabbed per tab terminal tends to be reduced.

  Therefore, an object of the present invention is to further reduce the resistance by connecting the tab terminal and the electrode foil reliably both mechanically and electrically without performing special processing on the tab terminal itself. There is.

  In order to solve the above-described problems, the present invention provides a tab terminal connecting method to an aluminum electrode foil, wherein the tab terminal flat portion of the tab terminal is connected to the aluminum electrode foil. The flat part of the terminal is overlaid on the aluminum electrode foil, and a cone-shaped caulking needle is pierced from above the flat part to form a petal-like nail piece protruding toward the aluminum electrode foil around the piercing hole, After the nail pieces are pressure-bonded to the aluminum electrode foil with a predetermined jig, laser welding is further applied to the pressure-bonded portion of the nail pieces.

  In this case, as described in claim 2, it is preferable to perform laser welding on the crimped portion from the aluminum electrode foil side.

  More preferably, as described in claim 3, of the plurality of claw pieces formed around the piercing hole, the laser welding is performed on the claw piece facing the central portion side of the aluminum electrode foil. It is good to give.

  On the other hand, as described in claim 4, laser welding on the crimped portion may be performed from the flat portion side, and such an aspect is also included in the present invention.

  Further, as described in claim 5, in the present invention, a pair of aluminum electrode foils to which tab terminals are connected according to any one of claims 1 to 4 is used as an anode foil and a cathode foil. An aluminum electrolytic capacitor impregnated with a predetermined electrolytic solution is also included.

  Moreover, as described in claim 6, in the present invention, a pair of aluminum electrode foils to which tab terminals are connected according to any one of claims 1 to 4 is used as an anode foil and a cathode foil. A solid electrolytic capacitor including a solid electrolyte made of a conductive polymer substance is also included.

  According to the present invention, the flat portion of the tab terminal is overlaid on the aluminum electrode foil, the cone-shaped caulking needle is pierced from above the flat portion, and the petal-like claw piece protruding toward the aluminum electrode foil side around the piercing hole is provided. After forming and crimping the nail pieces to the aluminum electrode foil with a predetermined jig, and further applying laser welding to the crimped portion of the nail pieces, the electrode foil has a high degree of roughening or the electrode Even when the foil is formed at a high voltage, the tab terminal and the electrode foil can be reliably connected both mechanically and electrically to further reduce the resistance.

  Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing a state in which the tab terminal is connected to the electrode foil by caulking according to the present invention, FIG. 2 is an enlarged cross-sectional view of the main part showing a state of laser welding after caulking, and FIG. It is the bottom view of FIG. 1 seen from the electrode foil side to show. Note that the same reference numerals are used for the same components as those of the conventional example described in FIG.

  First, as shown in FIG. 1, the tab terminal 1 is connected to the electrode foil 4 by caulking. The electrode foil 4 is made of an aluminum foil, and may be either an anode electrode foil or a cathode electrode foil. Further, the tab terminal 1 includes a terminal main body 2 and a CP wire (solder-plated copper-coated steel wire) 3 attached to the terminal main body 2 as in the conventional example of FIG. 4 described above.

  The terminal body 2 is formed by using a round bar wire made of aluminum as a base material, leaving a round bar portion 2a having a predetermined length, and integrally connecting a flat plate-like portion 2b, such as a press, to one end side thereof by, for example, pressing. The CP wire 3 is attached to the other end of the round bar 2a by welding.

  The flat portion 2b of the tab terminal 1 is overlaid on the electrode foil 4, and the caulking needle 5 is pierced from the flat portion 2b side. In the illustrated example, there are two caulking locations, but there may be 3 or more locations. Moreover, depending on the case, one place may be sufficient.

  As shown in FIG. 2, a piercing hole 5a penetrating the flat portion 2b and the electrode foil 4 is formed by the piercing of the caulking needle 5, and a petal-like shape protruding toward the electrode foil 4 around the piercing hole 5a. A claw piece 10 is formed.

  In order to electrically and mechanically connect the tab terminal 1 and the electrode foil 4, the claw piece 10 is pressed against the electrode foil 4 by pressing with a pressing tool (not shown). Thereafter, the laser beam emitted from the laser welding machine 11 is applied to the crimped portion of the claw piece 10 to perform laser welding.

  By this laser welding, the resistance of the connection portion between the tab terminal 1 and the electrode foil 4 can be reduced while maintaining or strengthening the mechanical connection strength by caulking. Laser welding may be performed from the flat portion 2b side, but is preferably performed from the electrode foil 4 side where the claw pieces 10 are present as shown in FIG.

  When laser welding is performed from the electrode foil 4 side, there are more preferable welding locations. For example, when a quadrangular pyramid needle is used for the caulking needle 5, as shown in FIG. 3, four claw pieces 10a to 10d having a petal shape corresponding to each cone surface are formed around the piercing hole 5a. In addition, in FIG. 3, it has shown in the state after each nail | claw piece was crimped | bonded.

  Here, of the four claw pieces 10a to 10d, the claw pieces 10a and 10b are arranged on the edge 4a side of the electrode foil 4, and the claw pieces 10c and 10d are directed toward the central portion 4b in the width direction of the electrode foil 4. In the case of being arranged, if the claw pieces 10a and 10b are irradiated with laser light, the foil may break due to the impact. Therefore, it is most preferable to irradiate the claw pieces 10c and 10d with laser light. This can also be said when laser welding is performed from the flat portion 2b side.

  Thirty tab terminals having a flat portion with a width of 2.5 mm and a thickness of 190 μm, 15 46 V conversion anode electrode foils with a thickness of 100 μm and a width of 2.2 mm, and 15 cathode electrode foils with a thickness of 60 μm and a width of 2.2 mm. Prepared.

[Example 1]
The flat part of the tab terminal was overlaid on the electrode foil, a square pyramid caulking needle was pierced, the petal-like nail piece was crimped, and laser welding was performed from the tab terminal side. There were two caulking locations, and each point was irradiated with laser. In Example 1, since there is a possibility that the electrode foil breaks when aiming at the nail piece on the edge side of the electrode foil, the nail piece on the central portion side of the electrode foil was irradiated with laser.

[Example 2]
The flat part of the tab terminal was overlapped on the electrode foil, a square pyramid caulking needle was pierced, the petal-like nail piece was crimped, and the nail piece portion was laser-welded from the electrode foil side. There were two caulking locations, and each of the nail pieces on the central portion side of the electrode foil was irradiated with a laser beam one by one. Laser welding was performed with a slightly lower output than in Example 1. Further, when aiming at the petal-like nail piece, the position was confirmed with a camera and welding was performed.

[Comparative Example 1]
The flat part of the tab terminal was overlaid on the electrode foil, and a square pyramid caulking needle was pierced, and only petal-like claw pieces were crimped and laser welding was not performed. There were two caulking locations.

  Next, the contact resistance (unit: mΩ) of the electrode foils with tab terminals prepared in Examples 1 and 2 and Comparative Example 1 was measured. Samples were 5 for each of Examples 1 and 2 and Comparative Example 1, 1-5, and the measured values of the anode electrode foil are shown in Table 1, and the measured values of the cathode electrode foil are shown in Table 2.

  According to Tables 1 and 2, it can be seen that Examples 1 and 2 using both caulking and laser welding have lower contact resistance than Comparative Example 1 using only caulking. Also, of Examples 1 and 2, the contact resistance of Example 2 laser welded from the electrode foil side is lower than that of Example 1 laser welded from the tab terminal side. This is because, as in Example 1, when laser welding is performed from the tab terminal side, the thick tab terminal is rejected and welding cannot be performed cleanly, and the broken part of the film cannot be accurately aimed.

  In Example 2, there are two caulking locations, and each of the nail pieces existing on the central portion side of the electrode foil is irradiated with a laser beam one by one, but the reliability of electrical and mechanical connection is further improved. If this is the case, laser welding may be performed on the other nail piece present on the central portion side of the electrode foil.

  As for the peel strength, when peeled by hand, Examples 1 and 2 seemed to have the same degree of peel strength, but they were clearly stronger than Comparative Example 1.

  Next, an aluminum solid electrolytic capacitor having a conductive polymer as a solid electrolyte using the anode electrode foil and the cathode electrode foil according to Example 2 and the anode electrode foil and the cathode electrode foil according to Comparative Example 1 in the following procedure. Each was produced.

  A capacitor element is produced by winding an anode electrode foil and a cathode electrode foil attached with a tab terminal through a separator, and this capacitor element is impregnated with 3,4-ethylenedioxythiophene as a conductive polymer and polymerized. After forming a solid electrolyte, the separator is heat-treated and carbonized, and then stored in a bottomed cylindrical aluminum metal case, and the opening is sealed with a sealing body. A foil wound aluminum solid electrolytic capacitor using a solid electrolyte made of

  This aluminum solid electrolytic capacitor has a diameter of 6 mm, a height of 5.7 mm, a rated voltage of 16 V, and a capacitance of 39 μF. The solid electrolytic capacitor using the electrode foil according to Example 2 was set as Example 3, and the solid electrolytic capacitor using the electrode foil according to Comparative Example 1 was set as Comparative Example 2. These capacitance (μF) and loss tangent (tan δ) ), Measured values of equivalent series resistance (ESR (mΩ)) and leakage current (μA) are shown in Table 3.

  As shown in Table 3, it can be seen that the aluminum solid electrolytic capacitor of Example 3 has less equivalent series resistance and leakage current than the aluminum solid electrolytic capacitor of Comparative Example 2.

  An aluminum solid electrolytic capacitor has a low resistance and very little leakage current in the first place, and it is very difficult to reduce this even at 1 mΩ or 1 μA. According to the present invention, the equivalent series resistance is 29.2-27. .9 = 1.3 (m.OMEGA.) And the leakage current is reduced by 13.4-10.2 = 3.2 (.mu.A), and this numerical value is significant.

  In the above embodiment, aluminum is used for the electrode foil, but a valve metal foil such as tantalum or titanium, an alloy foil thereof, or a vapor deposition foil may be used for the electrode foil.

  In addition, although 3,4-ethylenedioxythiophene is adopted as the conductive polymer, various monomers that become conductive polymers by oxidative polymerization, such as pyrrole, thiophene, furan, aniline, and derivatives thereof, are also used. Can be used.

Examples of the oxidizing agent include an aqueous oxidizing agent and an organic solvent oxidizing agent. Examples of the aqueous oxidizing agent include peroxodisulfuric acid and its Na salt, K salt, NH ₄ salt, cerium nitrate (IV ), Cerium (IV) ammonium nitrate, iron (III) sulfate, iron (III) nitrate, iron (III) chloride and the like.

  Examples of organic solvent-based oxidizing agents include ferric salts of organic sulfonic acids such as ferric paratoluenesulfonate, iron (III) dodecylbenzenesulfonate, and iron (III) p-toluenesulfonate. However, it is not limited to these.

  Examples of the solvent for the oxidant solution include ethers such as tetrahydrofuran (THF), dioxane, and diethyl ether; ketones such as acetone and methyl ethyl ketone, dimethylformamide, acetonitrile, benzonitrile, N-methylpyrrolidone (NMP), dimethyl sulfoxide ( An aprotic solvent such as DMSO), alcohols such as methanol, butanol, and propanol, water, or a mixed solvent thereof can be used. Preferably, water, alcohols or ketones or a mixed system thereof is desirable.

  The separator included in the capacitor element is preferably carbonized, but may not be carbonized. The solid electrolytic capacitor according to the present invention includes, in addition to the winding type, a laminated solid electrolytic capacitor in which an anode electrode foil and a cathode electrode foil each having a tab terminal attached thereto are laminated via a separator.

The typical perspective view showing the state where a tab terminal is connected to electrode foil by caulking in the present invention. The principal part expanded sectional view which shows the state welded after caulking. The bottom view of FIG. 1 seen from the electrode foil side which shows the connection part which crimps. The schematic diagram which shows a 1st prior art example. The schematic diagram which shows a 2nd prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tab terminal 2 Terminal body 2a Round bar part 2b Flat part 3 CP wire 4 Electrode foil 5 Caulking needle 5a Puncture hole 10, 10a-10d Claw piece 11 Laser welding machine

Claims (6)

In the tab terminal connection method for the aluminum electrode foil that connects the flat portion of the tab terminal to the aluminum electrode foil,
The flat portion of the tab terminal is overlaid on the aluminum electrode foil, and a cone-shaped caulking needle is pierced from the flat portion to form a petal-like claw piece protruding toward the aluminum electrode foil around the piercing hole. A method of connecting a tab terminal to an aluminum electrode foil, wherein the claw piece is pressure-bonded to the aluminum electrode foil with a predetermined jig, and further, laser welding is applied to a pressure-bonded portion of the claw piece.   The method of connecting a tab terminal to an aluminum electrode foil according to claim 1, wherein laser welding of the crimped portion is performed from the aluminum electrode foil side.   3. The laser welding is performed on a claw piece facing a central portion of the aluminum electrode foil among a plurality of claw pieces formed around the piercing hole. 4. Connection method of tab terminal to aluminum electrode foil.   The method of connecting a tab terminal to an aluminum electrode foil according to claim 1, wherein laser welding is performed on the crimped portion from the flat portion side.   An aluminum electrolytic capacitor in which a pair of aluminum electrode foils to which tab terminals are connected according to any one of claims 1 to 4 is used as an anode foil and a cathode foil and impregnated with a predetermined electrolytic solution.   A solid electrolytic capacitor comprising a solid electrolyte made of a conductive polymer substance, wherein a pair of aluminum electrode foils to which a tab terminal is connected according to any one of claims 1 to 4 is used as an anode foil and a cathode foil.

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