JP5982983B2 - Capacitor manufacturing method - Google Patents

Description

The present invention relates to a capacitor such as an electrolytic capacitor and an electric double layer capacitor. For example, a method of manufacturing a capacitor using a cold weld method, stitch connection, or ultrasonic welding for connection between an electrode foil and a lead terminal of a capacitor element About.

  In capacitor elements of capacitors such as electrolytic capacitors and electric double layer capacitors, a separator is placed between the electrode foils on the anode side and the cathode side and wound, and then impregnated with an electrolytic solution, or the electrode foils and the separators are alternately placed. After the lamination, the electrolytic solution is impregnated. The electrode foil on the anode side is subjected to a chemical conversion treatment on the foil that has been subjected to the etching treatment to form a dielectric film. For example, the electrode foil on the cathode side is subjected to an etching treatment, and a chemical conversion treatment is performed as necessary to form a dielectric film. A lead terminal is connected to any electrode foil, and for example, cold welding, stitching, or ultrasonic welding is used to connect the lead terminal to the electrode foil. Cold pressure welding is a method of pressure welding the stacked members in a non-heated state. Stitching is a method in which a cut-and-raised portion generated by the penetration of a stitch needle is passed between members, and an electrode foil is sandwiched between the cut-and-raised portion and a lead-out terminal and compressed and fixed. Ultrasonic welding is a method of welding by applying ultrasonic energy between members.

In connection by the cold welding method, it is known to use a die having a trapezoidal pressing surface as a die that presses against a connection portion between an electrode foil and a lead terminal (for example, Patent Document 1 and Patent Document 2). ). In connection by stitch processing, it is known that an electrode foil and a lead terminal are overlapped to pierce a needle to form a cut-and-raised portion and press the cut-raised portion (for example, Patent Document 3).

JP 7-235453 A JP 2007-273645 A JP 58-23428 A

  By the way, in the manufacture of a capacitor, in the connection between the lead terminal and the electrode foil by cold pressure welding, the electrode foil is placed on the lead terminal installed on the flat mold and the pressure welding mold is pressed from the electrode foil. . The electrode foil is sandwiched between the pressure contact mold and the lead terminal. Due to the pressing of the press-contacting die, a joint portion of the electrode foil and the lead terminal is generated by the tip end portion of the press-contacting die.

  Due to the pressing of the press contact mold, the electrode foil and the lead terminal are deformed according to the tip shape of the press contact mold. The lead terminal exhibits a metal flow in the width direction around the above-described joint and causes elongation. Following this elongation, the electrode foil is elongated in the radial direction. Thus, in the part where elongation has occurred, there is a problem that the connection between the electrode foil and the lead terminal becomes incomplete.

  On the other hand, the electrode foil and the lead terminal are fixed at the joint. Thinning occurs in the electrode foil extending around the joint. The electrode foil is thinner than the lead terminal, and thinning due to elongation weakens the electrode foil, and there is a problem that the connection strength between the lead terminal and the electrode foil is lowered.

  In stitch processing, the cut-and-raised portion generated in the lead-out terminal due to the penetration of the stitch needle is passed through the electrode foil and crushed. When the cut and raised portion is crushed, the lead terminal is pressed. As a result, when the lead terminal is deformed, the electrode foil stretches following this. Thereby, there exists a subject that electrode foil weakens and the connection strength of an extraction terminal and electrode foil is reduced.

  Even in the ultrasonic welding, when the drawer terminal is deformed by pressurization, the electrode foil stretches and weakens following this, and the connection strength between the drawer terminal and the electrode foil is lowered.

Therefore, in view of the above problems, an object of the present invention is to suppress the elongation of the lead terminal due to pressurization and prevent the electrode foil from being elongated and weakened.

In order to achieve the above object, a method of manufacturing a capacitor according to the present invention includes a step of disposing a first restraining jig on at least a side surface of a lead terminal, a step of forming a recess in the lead terminal, and the step of forming the lead terminal . A step of covering the recess and stacking the electrode foil on the extraction terminal, and pressing the cold pressure welding die from the electrode foil side superimposed on the recess of the extraction terminal and restraining the extraction terminal by the restraining jig However, the method includes a step of connecting the extraction terminal and the electrode foil.

  In order to achieve the above object, a method of manufacturing a capacitor according to the present invention includes a step of superimposing an extraction terminal on an electrode foil, and a stitch needle penetrating from the side of the extraction terminal superimposed on the electrode foil, and a cut generated in the extraction terminal. A step of penetrating the raising portion through the electrode foil, a step of arranging a first restraining jig on at least a side surface of the lead terminal, and restraining the lead terminal by the restraining jig, And press-contacting the electrode foil.

In the method for manufacturing a capacitor, a second restraining jig may be further disposed on the upper side of the electrode foil superimposed on the lead terminal.

  According to the present invention, the following effects can be obtained.

  (1) The extension of the lead terminal is suppressed, and the extension of the electrode foil following the lead terminal can be prevented.

  (2) The weakening of the electrode foil due to elongation can be prevented, and the connection strength with the lead terminal can be increased.

  (3) A highly reliable capacitor can be manufactured by preventing elongation and weakening of the electrode foil and increasing the connection strength with the lead terminal.

Other objects, features, and advantages of the present invention will become clearer with reference to the accompanying drawings and each embodiment.

It is sectional drawing which shows an example of the connection process of the electrode foil which concerns on 1st Embodiment, and an extraction terminal. It is a perspective view which shows an example of the original shape of an extraction terminal, and a restraining jig. It is sectional drawing which shows an example of the connection process of the electrode foil which concerns on 2nd Embodiment, and an extraction terminal. It is sectional drawing which shows an example of the connection process of the electrode foil which concerns on 3rd Embodiment, and an extraction terminal. It is sectional drawing which shows an example of the connection process of the electrode foil which concerns on 4th Embodiment, and an extraction terminal.

[First Embodiment]

  FIG. 1 shows a connection process between an electrode foil and a lead terminal according to the first embodiment. This connection process is a process included in the method for manufacturing a capacitor of the present invention.

  In this embodiment, the lead terminal 2 is connected to the electrode foil 4 using a cold welding method. In this connection, the lead terminal 2 is installed on the restraining jig 6, and the electrode foil 4 is pressed against the lead terminal 2 in a state of being restrained by the restraining jig 6. The capacitor manufacturing process includes an installation process of the lead terminal 2 (A in FIG. 1) and a restraining / pressing process (B in FIG. 1).

<Installation process>

  In this installation step, as shown in FIG. 1A, the extraction terminal 2 is installed on the restraining jig 6, and the extraction terminal 2 is restrained by the restraining jig 6 before the press contact with the electrode foil 4. The lead terminal 2 is provided with a flat part 2-1, and the electrode foil 4 is connected to the flat part 2-1.

  The restraining jig 6 is formed of, for example, a steel material and includes a flat portion 8 and a side wall portion 10 and has a U-shaped cross section. In other words, the restraining jig 6 is formed with a cavity 12 surrounded by the flat portion 8 and the side wall portion 10. The inner width W1 of the flat portion 8 is a width necessary for restraining the flat portion 2-1 of the lead terminal 2, and is set to be equal to the width W2 of the flat portion 2-1. The height H from the upper surface of the flat portion 8 of the side wall portion 10 is set to the same height (H = d) as the thickness d of the flat portion 2-1 of the lead terminal 2. H> d may be sufficient.

  The electrode foil 4 may be an anode-side electrode foil or a cathode-side electrode foil. In the anode-side electrode foil 4, as shown in FIG. 1A, an etching layer 16 is formed on the surface portion of the base material portion 14. The etching layer 16 is a surface-enlarging layer formed by performing an etching process on the base material of the electrode foil 4, and a dielectric film is formed on the etching layer 16 by a chemical conversion process. The surface expansion layer is a surface layer that expands the surface area of the electrode foil 4 in order to increase the capacitance. Although not shown, in the cathode-side electrode foil 4, an etching layer 16 is formed on the surface layer of the base material portion 14.

  The flat part 2-1 of the lead terminal 2 is installed in the cavity 12 of the restraining jig 6. The electrode foil 4 is placed so as to cover the flat part 2-1 and the side wall part 10 of the restraining jig 6.

  The press-contact mold 18 is positioned on the central axis of the flat part 2-1. The press contact mold 18 includes a tip press contact portion 20, a side press contact portion 22, and a base portion 24. The tip pressure contact portion 20 may be either spherical or trapezoidal, but is preferably spherical. Since the spherical shape does not have corners, local stress concentration on the electrode foil 4 can be prevented, and uniform pressure stress can be obtained. Thereby, a crack and foil crack can be prevented. Even if the tip pressure contact portion 20 has a trapezoidal shape, local concentration of the pressure stress can be similarly prevented if the corner portion is curved. The side pressure contact portion 22 has a truncated cone shape. The side pressure contact portion 22 has a diameter that is the minimum width of the tip pressure contact portion 20 and is continuously formed in a larger diameter as the distance from the tip pressure contact portion 20 increases. The base portion 24 has the same diameter.

<Restraining and pressure welding process>

  In the restraining / pressing step, the press-contacting die 18 is lowered in the arrow direction a in the state shown in FIG. 1A, and the flat portion 2-1 in a restrained state is pressed from the electrode foil 4.

  When the press-contact mold 18 is pressed, the electrode foil 4 is bent along the shape of the tip press-contact portion 20 of the press-contact mold 18 as shown in FIG. 26 is formed. A junction 28 between the electrode foil 4 and the lead terminal 2 is generated at the deepest portion of the curved recess 26. The joint portion 28 is a portion connected by pressure welding.

  Since the flat part 2-1 of the lead terminal 2 in which the curved recessed part 26 is formed is restrained by each side wall part 10 of the restraining jig 6, the metal flow in the side surface direction is suppressed. For this reason, the flat part 2-1 of the lead-out terminal 2 races up to the peripheral surface side of the press contact mold 18. Arrow b indicates the direction of metal flow. That is, a mortar-shaped curved concave portion 26 that covers the side surface pressure contact portion 22 of the pressure contact mold 18 is formed. Since the electrode foil 4 is interposed between the press contact mold 18 and the flat portion 2-1 where the lead terminal 2 is deformed, the expansion angle of the curved recess 26 is the expansion angle of the side press contact section 22 of the press contact mold 18. Bigger than.

  Thus, the restraining jig 6 can prevent the flat portion 2-1 of the lead terminal 2 from being deformed in the side surface direction. That is, it is possible to concentrate stresses from the tip press contact portion 20 and the side press contact portion 22 of the press contact mold 18 on the curved concave portion 26 of the flat portion 2-1. The flat portion 2-1 can be prevented from stretching in the side surface direction, and the electrode foil 4 following the elongation can be prevented from stretching. Thinning due to elongation of the electrode foil 4 can be prevented, and weakening can be suppressed. Therefore, the connection strength between the electrode foil 4 and the flat part 2-1 of the lead terminal 2 can be increased.

  <Drawer terminal 2 original shape and restraint jig 6>

  FIG. 2 shows an example of the original shape of the lead terminal 2 and the restraining jig 6. The lead terminal 2 includes the flat part 2-1 and the lead part 2-2 described above. The flat portion 2-1 may be formed by flatly forming a rod-like material similar to the lead portion 2-2, or may be a separate member. If it is another member, the flat part 2-1 is formed of the same as the electrode foil 4, for example, aluminum, the lead part 2-2 is formed of a solderable metal, and these are welded to form the lead terminal 2. May be. The flat portion 2-1 has a length L and a width W2.

  The restraining jig 6 has the flat portion 8 described above formed in a rectangular shape. The length of the flat portion 8 may be formed equal to the length L of the flat portion 2-1 of the lead terminal 2.

  According to such a configuration, the above-described connection can be performed easily and reliably, and extension of the flat portion 2-1 of the lead terminal 2 in the side surface direction (W direction) can be prevented. By preventing the elongation, the electrode foil 4 can be prevented from stretching, and the electrode foil 4 can be prevented from being weakened due to the pressure contact connection.

[Second Embodiment]

  FIG. 3 shows a connection process between the electrode foil and the lead terminal according to the second embodiment. In FIG. 3, the same parts as those in FIG.

  In this connection step, the above-described restraining jig 6 is used as the first restraining jig 6-1, and the second restraining jig 6-2 is used in combination.

<Installation process>

  In this installation step, as shown in FIG. 3A, the extraction terminal 2 is installed on the restraining jig 6-1, and the extraction terminal 2 is restrained by the restraining jig 6-1 before the pressure contact with the electrode foil 4. . Since the shape of the restraining jig 6-1 is the same as that of the restraining jig 6 described above, the description thereof is omitted.

  The electrode foil 4 is installed so as to cover the flat part 2-1 of the lead terminal 2 installed in the restraining jig 6-1 and the side wall part 10 of the restraining jig 6-1.

  A restraining jig 6-2 is installed on the upper surface side of the electrode foil 4 across the side wall 10 of the electrode foil 4 and the restraining jig 6-1. The restraining jig 6-2 is formed with a window portion 30 through which the press contact mold 18 is inserted. The width W3 of the window portion 30 may be set larger than the diameter R of the press contact mold 18.

<Restraining and pressure welding process>

  In this restraint / pressure contact process, as shown in FIG. 3B, the restraint jigs 6-1 and 6-2 are restrained and the pressure contact mold 18 is lowered in the arrow direction a to restrain the electrode foil 4 from being restrained. The flat part 2-1 of the lead terminal 2 is pressed.

  In this way, stresses from the distal end pressure contact portion 20 and the side surface pressure contact portion 22 of the pressure contact mold 18 can be concentrated on the curved concave portion 26 of the flat portion 2-1. Elongation of the flat part 2-1 in the side surface direction (W direction) can be prevented, the electrode foil 4 following the elongation can be prevented from being stretched, and extreme deformation such as jumping up of the electrode foil 4 can be prevented. Thinning due to elongation of the electrode foil 4 can be prevented, and weakening can be suppressed. Therefore, the connection strength between the electrode foil 4 and the flat part 2-1 of the lead terminal 2 can be further increased.

  In the first and second embodiments, after the electrode foil 4 is overlaid on the lead terminal 2, a cold pressure welding die is pressed from the electrode foil 4 side and connected. In this way, the lead terminal 2 may be connected without processing, but after forming a recess in the lead terminal 2 in advance, the electrode foil 4 is overlaid on the lead terminal 2 so as to cover the recess, and then the electrode foil You may connect by pressing a cold-pressure-welding metal mold | die from 4 side. In this way, after the electrode foil 4 enters the recess, the electrode foil 4 is not pressed and thinned locally because the electrode foil 4 is pressed evenly against the side and bottom surfaces of the recess. Occurrence can be further prevented.

  In the first embodiment and the second embodiment, the metal flow in the side surface direction of the flat part 2-1 is suppressed. For this reason, there is no metal flow in the side surface direction of the connecting portion of the lead terminal 2, and no trace is generated. That is, in the side surface direction of the connecting portion of the lead terminal 2, there is no so-called streak indicating elongation due to metal flow. On the other hand, there is no side wall portion 10 in the direction of the lead portion 2-2 of the flat portion 2-1, and the metal flow cannot be suppressed. For this reason, streaks representing traces of metal flow are generated on the surface of the flat part 2-1 on the lead part 2-2 side of the connection part. In other words, the generation of streaks indicates the presence or absence of metal flow.

[Third Embodiment]

  FIG. 4 shows a connection process between the electrode foil and the lead terminal according to the third embodiment. In FIG. 4, the same parts as those in FIG.

  In this embodiment, the lead terminal 2 is connected to the electrode foil 4 by using a stitch processing method. This connection includes an arrangement process (A in FIG. 4), a stitching process (B in FIG. 4), and a restraining process (C in FIG. 4) of the lead terminals 2 and the electrode foils 4.

<Arrangement process>

  In this arrangement step, as shown in FIG. 4A, the flat portion 2-1 of the lead terminal 2 is arranged at the connection portion of the electrode foil 4, and positioning before stitching is performed.

<Stitching process>

  In this stitch processing step, as shown in FIG. 4B, the stitch needle 32 is penetrated from above the flat portion 2-1 of the lead terminal 2 superimposed on the connection portion of the electrode foil 4. The stitch needle 32 has a quadrangular pyramid tip with an acute apex angle, and the ridge line portion 34 forms a cutting blade.

  When such a stitch needle 32 is passed through the lead-out terminal 2, a cut-and-raised part 36 is formed in the flat part 2-1. This cut-and-raised portion 36 is a metal piece generated by the shape of the tip of the stitch needle 32. In this embodiment, four cut-and-raised portions 36 are formed by the tip of a quadrangular pyramid needle.

  Compared to the electrode foil 4, since the flat part 2-1 of the lead terminal 2 is thick, the cut-and-raised part 36 has a length exceeding the thickness of the electrode foil 4 and has an acute angle. For this reason, the cut-and-raised portion 36 generated following the intrusion of the stitch needle 32 penetrates the electrode foil 4 while being guided by the stitch needle 32 and reaches the back side of the electrode foil 4. When the stitch needle 32 is pulled out in this state, the cut and raised portion 36 is maintained in a state of penetrating the electrode foil 4. A through hole 38 is formed in the flat part 2-1.

<Restricted machining process>

  In the restraining step, as shown in FIG. 4C, the restraining jig 6 described above is installed in the flat part 2-1 of the lead terminal 2, and the flat part 2-1 is restrained by the restraining jig 6.

  In a state where the flat portion 2-1 is constrained by the restraining jig 6, the cut and raised portion 36 is pressed against the flat mold 40 and is formed in close contact with the surface of the electrode foil 4.

  Thus, since the flat part 2-1 is restrained by the restraining jig 6, deformation of the lead-out terminal 2 can be prevented by the restraining jig 6 and the flat mold 40, and the cut-and-raised part 36 can be formed. Since deformation of the flat part 2-1 and metal flow do not occur, stress can be concentrated on the formation of the cut and raised part 36. That is, since the extension of the lead terminal 2 can be prevented, the extension and thinning of the electrode foil 4 due to the extension can be prevented, and the connection strength between the lead terminal 2 and the electrode foil 4 can be increased.

[Fourth Embodiment]

  FIG. 5 shows a process of connecting the electrode foil and the lead terminal according to the fourth embodiment. 5, the same parts as those in FIG. 4 are denoted by the same reference numerals.

  In this embodiment, the lead terminal 2 is connected to the electrode foil 4 by using a stitch processing method, and the first and second restraining jigs 6-1 and 6-2 are used for forming the cut and raised portion 36.

  Although the flat mold 40 is used in the third embodiment, a forming mold 42 and a restraining jig 6-2 are used instead of the flat mold 40. The molding die 42 is in charge of molding the cut and raised portion 36 described above. Restraint jig 6-1 A restraint jig 6-2 is placed on the electrode foil 4 that has been cut and raised from the lead-out terminal 2 that is restrained. The restraining jig 6-2 has an interval 44 or an opening larger than the forming width of the cut and raised portion 36. A molding die 42 is installed in the interval 44, and the cut-and-raised portion 36 is formed flat by the molding die 42.

  Thus, if the shaping | molding die 42 and the restraining jig 6-2 are used with the restraining jig 6-1, the deformation | transformation of the extraction | drawer terminal 2 can be prevented and the jumping and elongation of the electrode foil 4 can be prevented. Thinning and weakening of the electrode foil 4 can be prevented, and the connection strength with the extraction terminal 2 can be increased.

  In the third and fourth embodiments, the stitch needle 32 is penetrated from the lead terminal 2 side overlapped with the electrode foil 4, and the cut-and-raised portion 36 generated in the lead terminal 2 is penetrated through the electrode foil 4. . In this way, the cut and raised portions 36 may penetrate the electrode foil 4, but holes may be formed in the electrode foil 4 in advance. Even if the extraction terminal 2 is overlaid on the electrode foil 4, the stitch needle 32 is inserted into the hole of the electrode foil 4 from the extraction terminal 2 side, and the cut-and-raised portion 36 generated in the extraction terminal 2 is passed through the hole of the electrode foil 4. Good. If the cut-and-raised part 36 is brought into contact with the inner peripheral surface of the hole formed in this way, the bare metal of the electrode foil 4 on which the dielectric film is not formed and the cut-and-raised part 36 are brought into direct contact with the electrode foil 4. It is possible to join them. That is, it is possible to avoid the influence on the electrical connection due to the insulating property of the dielectric film, and to improve the electrical connectivity between the anode-side electrode foil 4 and the lead terminal 2.

[Other Embodiments]

  (1) In the above embodiment, the connection between the lead terminal and the electrode foil by the cold welding method or the stitching process is exemplified, but the present invention is not limited to this. Ultrasonic welding may be used to connect the extraction terminal and the electrode foil. In this ultrasonic welding, the extension of the lead terminal 2 can be prevented by using the restraining jig 6 or the restraining jigs 6-1 and 6-2 described above when applying ultrasonic vibration to the lead terminal. The same effects as those of the embodiment described above can be obtained.

  (2) In the above embodiment, the connection between the electrode foil and the lead terminal is shown in the capacitor manufacturing process. It goes without saying that the manufacture of a capacitor includes the formation of a capacitor element using an electrode foil connected with a lead terminal, an impregnation step with an electrolytic solution, a sealing step in an outer case, and a sealing step in the outer case.

As described above, the most preferable embodiment of the present invention has been described. The present invention is not limited to the above description. Various modifications and changes can be made by those skilled in the art based on the gist of the invention described in the claims or disclosed in the embodiments for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present invention.

The present invention can prevent deformation such as elongation of a lead terminal when performing cold pressure welding, stitch processing, or ultrasonic welding for connection between the lead terminal and the electrode foil. The elongation and thinning of the electrode foil following this elongation can be prevented, and the weakening of the electrode foil can be avoided. The connection strength between the electrode foil and the lead terminal can be increased. This contributes to improving the reliability of the capacitor and is extremely useful.

DESCRIPTION OF SYMBOLS 2 Lead terminal 2-1 Flat part 2-2 Lead part 4 Electrode foil 6 Restraint jig 6-1 1st restraint jig 6-2 2nd restraint jig 8 Flat part 10 Side wall part 12 Cavity 14 Base material part Reference Signs List 16 etching layer 18 pressure contact mold 20 tip pressure contact portion 22 side surface pressure contact portion 24 base body portion 26 curved concave portion 28 joint portion 30 window portion 32 stitch needle 34 ridge line portion 36 cut and raised portion 38 through hole 40 flat die 42 molding die 44 interval portion

Claims (3)

Arranging a first restraining jig on at least a side surface of the lead terminal;
Forming a recess in the lead terminal;
Covering the concave portion of the lead terminal and overlaying an electrode foil on the lead terminal ;
Connecting the lead terminal and the electrode foil while pressing the cold pressure welding die from the electrode foil side overlaid on the concave portion of the lead terminal and restraining the lead terminal by the restraining jig; ,
A method for producing a capacitor, comprising: A step of superimposing a lead terminal on the electrode foil;
Penetrating a stitch needle from the lead terminal side superimposed on the electrode foil, penetrating a cut and raised portion generated in the lead terminal into the electrode foil, and
Disposing a first restraining jig on at least a side surface of the lead terminal;
A step of pressing the cut and raised portion against the electrode foil while restraining the lead terminal by the restraining jig;
A method for producing a capacitor, comprising: Further, a manufacturing method of a capacitor according to claim 1 or claim 2, characterized in that arranging the second constraining jig above the electrode foil superimposed on the lead-out terminals.

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