Electrolytic capacitor and method for manufacturing the same

Abstract

This electrolytic capacitor is provided with: an exterior body 30; and an element laminated body provided with a plurality of capacitor elements. The plurality of capacitor elements each have a positive electrode body, a dielectric layer, and a negative electrode part that covers at least a portion of the dielectric layer. The exterior body has a first main surface 31A, a second main surface 31B that crosses the first main surface, a third main surface 31C on the opposite side to the first main surface, and a fourth main surface 31D on the opposite side to the second main surface. Regarding at least one first capacitor element among the plurality of capacitor elements, an end surface of an end part of the positive electrode body is exposed from the exterior body in at least the first main surface 31A so as to be electrically connected to a first external electrode 50A, and an end surface of an end part of the negative electrode part is exposed from the exterior body in at least the second main surface 31B so as to be electrically connected to a second external electrode 50B. Provided is an electrolytic capacitor that achieves high capacitance while maintaining ESL at low level.

Description

Technical Field

[0001] The present disclosure relates to an electrolytic capacitor and a method for manufacturing the same.

Background Art

[0002] An electrolytic capacitor includes a capacitor element, an exterior body that seals the capacitor element, and external electrodes that are electrically connected to the anode side and the cathode side of the capacitor element, respectively. The capacitor element includes an anode body having a first portion (also referred to as an anode lead-out portion) including a first end and a second portion (also referred to as a cathode formation portion) including a second end, a dielectric layer formed on at least the surface of the second portion of the anode body, and a cathode portion that covers at least a part of the dielectric layer.

[0003] Patent Document 1 proposes a solid electrolytic capacitor including an element laminate in which flat capacitor elements each having an anode electrode portion and a cathode electrode portion are laminated in even units such that the anode electrode portions are arranged in directions opposite to each other alternately. The solid electrolytic capacitor of Patent Document 1 further includes a pair of anode rubber terminals joined so as to integrally connect the anode electrode portions located at both ends of the element laminate, a cathode rubber terminal joined to the lower surface of the cathode electrode portion located at the center of the element laminate, a pair of anode terminals provided on the lower surfaces of the pair of anode rubber terminals, respectively, and a pair of cathode terminals joined to the cathode rubber terminal, respectively. The pair of anode terminals are connected by a plate-shaped inductor portion, and the pair of cathode terminals are joined to both ends of the lower surface of the cathode rubber terminal, respectively, in a direction intersecting the inductor portion. In Patent Document 1, reduction of the ESL (equivalent series inductance) of the electrolytic capacitor is proposed by this configuration.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] An electrolytic capacitor according to one aspect of the present disclosure includes an element laminate including a plurality of capacitor elements, an exterior body that seals the element laminate, a first external electrode, and a second external electrode. Each of the plurality of capacitor elements has an anode body having a porous portion on its surface, a dielectric layer formed on at least a part of the surface of the porous portion, and a cathode portion covering at least a part of the dielectric layer. The exterior body has a first main surface, a second main surface intersecting the first main surface, a third main surface on the opposite side of the first main surface, and a fourth main surface on the opposite side of the second main surface. Among the plurality of capacitor elements, at least one first capacitor element has an end face of an end portion of the anode body exposed from the exterior body at least on the first main surface and electrically connected to the first external electrode, and an end face of an end portion of the cathode portion exposed from the exterior body at least on the second main surface and electrically connected to the second external electrode.

[0006] A method for manufacturing an electrolytic capacitor according to another aspect of the present disclosure is a method for manufacturing an electrolytic capacitor including an element laminate including a plurality of capacitor elements each having an anode body having a porous portion on its surface, a dielectric layer formed on at least a part of the surface of the porous portion, and a cathode portion covering at least a part of the dielectric layer. The method includes a step of obtaining an element assembly in which a plurality of the element laminates are arranged on a plane perpendicular to the stacking direction, a step of separating the element assembly into individual elements, and a step of electrically connecting an end portion of the anode body of the element laminate to a first external electrode and an end portion of the cathode portion to a second external electrode. The step of obtaining the element assembly includes: (i) a step of preparing an anode foil having the porous portion formed on its surface; (ii) a step of forming the dielectric layer on the surface of the anode foil; (iii )Front the anode on the foil , a step of forming a first opening; (iv) a step of forming a solid electrolyte layer in a first region of the anode foil; process a step of preparing a cathode foil processed into a shape having a second region partially facing the first region; and (vi) a step of alternately laminating the anode foil and the cathode foil. The first region of the anode foil, and frontThe arrangement pattern of the second region of the cathode foil has a periodic pattern in which unit patterns are periodically repeated in at least one of the first direction and the second direction intersecting the first direction. The unit pattern of the first region includes a region A1 located at the center in the first direction and a region A2 extending from the region A1 in the first direction. The unit pattern of the second region includes a region A3 corresponding to the region A1 of the anode foil and a region A4 extending from the region A3 in the second direction.

[0007] According to the present disclosure, a high capacitance can be achieved while maintaining a low ESL of the electrolytic capacitor.

Brief Description of the Drawings

[0008]

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[0009] Prior to the description of the embodiments, problems in the prior art are briefly shown below.

[0010] However, in the solid electrolytic capacitor described in Patent Document 1, since the anode electrode portion and the external electrode are electrically connected via the anode rubber terminal, the space occupied by the capacitor element is limited by the occupied space of the anode rubber terminal, and it is difficult to increase the capacitance of the capacitor.

[0011] In view of the above problems, the present disclosure provides an electrolytic capacitor capable of achieving a high capacitance while maintaining a low ESL, as well as a method for manufacturing the electrolytic capacitor.

[0012] [Electrolytic Capacitor] The electrolytic capacitor according to the present embodiment includes an element laminate including a plurality of capacitor elements, an exterior body that seals the element laminate, a first external electrode, and a second external electrode. Each of the plurality of capacitor elements has an anode body having a porous portion on the surface, a dielectric layer formed on at least a part of the surface of the porous portion, and a cathode portion covering at least a part of the dielectric layer. At least a part of the end of the anode body and at least a part of the end of the cathode portion are exposed from the exterior body and are electrically connected to the external electrode at the end face of the end exposed from the exterior body, thereby constituting an electrolytic capacitor having the element laminate.

[0013] The exterior body has a first main surface, a second main surface intersecting the first main surface, a third main surface on the opposite side of the first main surface, and a fourth main surface on the opposite side of the second main surface. In the plurality of capacitor elements, the ends of the anode body and the ends of the cathode portion can be exposed from the exterior body on at least one of these main surfaces. Hereinafter, the end faces of the ends of the anode body and the cathode portion on the first main surface to the fourth main surface sides of the exterior body are referred to as the first end face to the fourth end face, respectively.

[0014] Among a plurality of capacitor elements, at least one first capacitor element has an end face of an anode body exposed from the exterior body at least on a first main surface and electrically connected to a first external electrode (anode electrode), and an end face of a cathode portion exposed from the exterior body at least on a second main surface and electrically connected to a second external electrode (cathode electrode). That is, the end of the anode body and the end of the cathode portion are connected to the external electrodes on the sides of the main surfaces that intersect each other. In this case, the first external electrode and the second external electrode can be provided on the main surfaces that intersect each other. Thereby, compared with the conventional configuration in which the first external electrode and the second external electrode are provided on the main surfaces facing each other, the separation distance between the first external electrode and the second external electrode can be shortened, and the ESL can be reduced.

[0015] In the present embodiment, the end of the anode body includes a pair of first ends facing each other in a first direction. The end of the cathode portion includes a pair of second ends facing each other in a second direction intersecting the first direction. In this case, in the plurality of capacitor elements, a first end face A, which is one end face of the pair of first ends, may be exposed from the exterior body on the first main surface of the exterior body, and / or a third end face A, which is the other end face of the pair of first ends, may be exposed from the exterior body on the third main surface of the exterior body. Also, a second end face A, which is one end face of the pair of second ends, may be exposed from the exterior body on the second main surface of the exterior body, and / or a fourth end face A, which is the other end face of the pair of second ends, may be exposed from the exterior body on the fourth main surface of the exterior body. Among the plurality of capacitor elements, at least one first capacitor element has the first end face A exposed from the exterior body and electrically connected to the first external electrode (anode electrode), and the second end face A exposed from the exterior body and electrically connected to the second external electrode (cathode electrode).

[0016] The first capacitor element may further have a third end face A exposed from the exterior body and be electrically connected to a third external electrode (anode electrode). That is, the first end portions may be connected to the external electrode (anode electrode) on both of the main faces facing each other. In this case, the first external electrode and the third external electrode may be provided separately on both of the main faces facing each other. In this case, by forming an anode terminal with a plurality of separated external electrodes, the ESL can be further reduced.

[0017] Either one of the first external electrode and the third external electrode may be connected to the anode terminal portion of the external circuit board, or both of them may be connected to the anode terminal portion. By providing the first external electrode and the third external electrode, the degree of freedom in mounting on the substrate of the electrolytic capacitor increases. By connecting both the first external electrode and the third external electrode to the anode terminal portion of the external circuit board, not only can the ESR be reduced, but the ESL can also be further reduced.

[0018] The first capacitor element may also have a fourth end face A exposed from the exterior body and be electrically connected to a fourth external electrode (cathode electrode). That is, the second end portions may be connected to the external electrode (cathode electrode) on both of the main faces facing each other. In this case, the second external electrode and the 4 fourth external electrode may be provided separately on both of the main faces facing each other. In this case, by forming a cathode terminal with a plurality of separated external electrodes, the ESL can be further reduced.

[0019] Either one of the second external electrode and the fourth external electrode may be connected to the cathode terminal portion of the external circuit board, or both of them may be connected to the cathode terminal portion. By providing the second external electrode and the fourth external electrode, the degree of freedom in mounting on the substrate of the electrolytic capacitor increases. By connecting both the second external electrode and the fourth external electrode to the cathode terminal portion of the external circuit board, not only can the ESR be reduced, but the ESL can also be further reduced.

[0020] The first to fourth external electrodes can be provided along the first to fourth main surfaces of the exterior body, respectively. Among these, the first and third external electrodes can form the anode electrode of the electrolytic capacitor. The second and fourth external electrodes can form the cathode electrode of the electrolytic capacitor. For each of the plurality of capacitor elements constituting the element laminate, at least one of the pair of first end portions is electrically connected to the first external electrode or the third external electrode, and at least one of the pair of second end portions is electrically connected to the second external electrode or the fourth external electrode.

[0021] The plurality of capacitor elements may have a second capacitor element whose first end face B is not exposed from the exterior body. In the second capacitor element, instead of the first end face B not being exposed from the exterior body and not being electrically connected to the first external electrode, the third end face B is exposed from the exterior body and is electrically connected to the third external electrode.

[0022] In this case, in the element laminate, the first capacitor element and the second capacitor element may be alternately laminated. In this case, a first capacitor element whose third end face A is not exposed from the exterior body and whose first end portion is electrically connected only to the first external electrode, and a second capacitor element whose first end portion is electrically connected only to the third external electrode may be alternately laminated. As described above, since the first external electrode and the third external electrode are provided on mutually opposing surfaces of the exterior body, the direction of the current flowing through the anode body is reversed between the first capacitor element and the second capacitor element. Therefore, since the directions of the magnetic fields generated by the current are different, the magnetic flux generated in the element laminate is reduced. As a result, the ESL can be further reduced.

[0023] In particular, when the first capacitor element and the second capacitor element are alternately laminated, the magnetic flux generated in the element laminate can be effectively reduced. Therefore, the ESL can be effectively reduced. The number of the first capacitors element and the number of the second capacitors element may be the same. The number of the first capacitors element and the number of the second capacitors elementIf the number is the same, the magnetic field generated by the current flowing through the anode body of the first capacitor element and the magnetic field generated by the current flowing through the anode body of the second capacitor element cancel each other out without excess or deficiency, and the magnetic flux generated in the element laminate decreases. Therefore, it is easy to reduce the ESL.

[0024] In the second capacitor element, the second end portion is electrically connected to at least one of the second external electrode and the fourth external electrode. In the second capacitor element, either one of the second end face B and the fourth end face B may be exposed from the exterior body (and the other is not exposed from the exterior body), and the second external electrode or the fourth external electrode and the second end portion may be electrically connected, or both the second end face B and the fourth end face B may be exposed from the exterior body, and the second external electrode and the fourth external electrode and the second end portion may be electrically connected.

[0025] Further, the plurality of capacitor elements may include a third capacitor element in which the second end face C is not exposed from the exterior body. In the third capacitor element, the second end face C is not exposed from the exterior body, and instead of being electrically connected to the second external electrode, the fourth end face C is exposed from the exterior body and is electrically connected to the fourth external electrode.

[0026] In this case, in the element laminate, the first capacitor element and the third capacitor element may be alternately laminated. In this case, a first capacitor element in which the fourth end face A is not exposed from the exterior body and the second end portion is electrically connected only to the second external electrode, and a third capacitor element in which the second end portion is electrically connected only to the fourth external electrode may be alternately laminated. As described above, since the second external electrode and the fourth external electrode are provided on opposite surfaces of the exterior body, the directions of the currents flowing through the cathode portions are opposite between the first capacitor element and the third capacitor element. Therefore, since the directions of the magnetic fields generated by the currents are different, the magnetic flux generated in the element laminate decreases. Thereby, the ESL can be further reduced.

[0027] In particular, when the first capacitor element and the third capacitor element are alternately stacked, the magnetic flux generated in the element laminate can be effectively reduced. Therefore, the ESL can be effectively reduced. The number of the first capacitors element and the number of the third capacitors element may be the same. When the number of the first capacitors element and the number of the 3 capacitors element are the same, the magnetic field generated by the current flowing through the cathode portion of the first capacitor element and the magnetic field generated by the current flowing through the cathode portion of the third capacitor element cancel each other out without excess or deficiency, and the magnetic flux generated in the element laminate decreases. Therefore, it is easy to reduce the ESL.

[0028] In the third capacitor element, the first end portion is electrically connected to at least one of the first external electrode and the third external electrode. The third capacitor element may be one in which either the first end face C or the third end face C is exposed from the exterior body (and the other is not exposed from the exterior body), and the first external electrode or the third external electrode is electrically connected to the first end portion, or both the first end face C and the third end face C are exposed from the exterior body, and the first external electrode and the third external electrode are electrically connected to the first end portion.

[0029] The third capacitor element may be one in which the first end face C is not exposed from the exterior body and the third end face C is exposed from the exterior body and is electrically connected to the third external electrode. In this case, the third capacitor element also corresponds to the second capacitor element.

[0030] The electrical connection between the element laminate and the external electrodes can be achieved by electrically connecting the end faces (the first to fourth end faces) of the first and second ends of the capacitor element exposed from the exterior of each capacitor element to the external electrodes (the first to fourth external electrodes). The electrical connection between each end face and the external electrode can be made, for example, by using external electrodes formed along the first to fourth main faces of the exterior, or by electrically connecting an intermediate electrode layer formed along the first to fourth main faces to the external electrodes. In this case, since there is no need to interpose other members for connecting the first and second ends to the first to fourth external electrodes within the exterior, it becomes easy to increase the capacitance of the electrolytic capacitor.

[0031] Also, among the current paths from the part of the anode body where the cathode part is not formed (anode lead-out part) to the first or third external electrode, the current path flowing parallel to the lamination plane of the element laminate is substantially equal to the length of the anode lead-out part. Therefore, by shortening this length, the ESL generated by the current path flowing parallel to the lamination plane of the above-mentioned element laminate can be further reduced.

[0032] In each of the capacitor elements, the anode body may have a recess recessed in the second direction (the direction of the second end of the cathode part). A part of the cathode part may extend so as to protrude from the recess and may constitute the second end. The direction of the recess of the recess may be the normal direction of the second main face or the fourth main face. Thereby, it becomes easy to expose the end face (the second end face and / or the fourth end face) of the second end from the exterior and electrically connect it to the second external electrode or the fourth external electrode.

[0033] In the first capacitor, the end face (the second end face A) of the cathode part exposed from the exterior on the second main face may be located closer to the first main face where the first external electrode is provided than the third main face. In this case, the separation distance between the first external electrode and the second external electrode becomes shorter, and the ESL is further reduced.

[0034] In yet another embodiment, the first capacitor element may be such that a second end face A, which is an end face on the second main surface at the end of the cathode portion, is exposed from the exterior body and is electrically connected to the second external electrode, and a fourth end face A, which is an end face on the fourth main surface at the end of the cathode portion, is exposed from the exterior body and is electrically connected to the second external electrode. In this case, by providing the second end face A of the cathode portion of the first capacitor at a position closer to the first main surface than the third main surface, the ESL is significantly reduced.

[0035] In the above case, the end of the anode body may not be exposed from the third main surface of the exterior body, and a third end face A, which is an end face on the third main surface at the end of the cathode portion, may be exposed from the exterior body and the third end face A may be electrically connected to the third external electrode. That is, the third external electrode may be a cathode electrode, and the first external electrode, which is an anode electrode, and the third external electrode, which is a cathode electrode, may face each other. Alternatively, neither the end of the anode body nor the end of the cathode portion needs to be exposed from the third main surface of the exterior body. In the latter case, there is no need to provide the third external electrode. However, when the third external electrode is not provided, the fixing of the electrolytic capacitor to the external circuit board becomes unstable, and the electrical connection between the first external electrode and / or the second external electrode of the electrolytic capacitor and the electrode terminal portion provided on the external substrate may be disconnected due to impacts or vibrations during movement. Therefore, even when neither the end of the anode portion nor the end of the cathode portion is exposed from the third main surface of the exterior body, in order to stably fix the electrolytic capacitor to the external circuit board and suppress disconnection due to impacts and vibrations, it is preferable that the third external electrode is arranged so as to cover at least the side of the third main surface rather than the second external electrode on the bottom surface of the electrolytic capacitor.

[0036] The cathode portion has, for example, a solid electrolyte layer covering at least a part of the dielectric layer. The cathode portion may further have a cathode foil covering at least a part of the solid electrolyte layer. In this case, a part of the cathode foil covers the solid electrolyte layer, and the remaining portion of the cathode foil that does not cover the solid electrolyte layer may constitute an end portion (cathode lead-out portion) of the cathode foil. In this case, the end portion of the cathode foil may be a portion of the cathode foil that extends so as to protrude from the concave portion of the anode body.

[0037] Not all of the cathode portions need to have a cathode foil. For example, if a solid electrolyte layer and / or a conductive resin layer is formed so as to cover the end face in addition to the main face of the anode body, and the cathode portions formed on both faces of the anode body are electrically connected to each other, in at least one first capacitor element, by exposing the end face of the end portion of the cathode portion from the exterior body at least on the second main face, the effect of reducing ESL according to the present disclosure can be obtained.

[0038] The cathode foil is, for example, a metal foil and can be a sintered foil, a vapor-deposited foil, or a coated foil. The cathode foil may be a sintered foil, a vapor-deposited foil, or a coated foil in which the surface of a metal foil (for example, an Al foil or a Cu foil) is coated with a conductive film by vapor deposition or coating. The vapor-deposited foil may be an Al foil having Ni vapor-deposited on its surface. Examples of the conductive film include Ti, TiC, TiO, and a C (carbon) film. The conductive film may be a carbon coating film. Hereinafter, a method for manufacturing an electrolytic capacitor using such a cathode foil will be described in detail.

[0039] In the electrolytic capacitor of the present embodiment, the first external electrode or the third external electrode may be provided along a plane parallel to the longitudinal direction of the exterior body when the exterior body is viewed from the stacking direction of the element laminate, or may be provided along a plane parallel to the short-side direction of the exterior body. That is, in the exterior body, the separation distance between the first main face and the third main face may be shorter or longer than the separation distance between the second main face and the fourth main face. Generally, when the anode electrode is disposed on the first main face and the cathode electrode is disposed on the third main face, making the separation distance between the first main face and the third main face shorter than the separation distance between the second main face and the fourth main face shortens the distance between the anode electrode and the cathode electrode, thereby reducing the ESL. However, in the electrolytic capacitor of the present embodiment, since the first external electrode, which is the anode electrode, is disposed on the first main face and the second external electrode, which is the cathode electrode, is disposed on the second main face, even when the separation distance between the first main face and the third main face is longer than the separation distance between the second main face and the fourth main face, the ESL can be reduced by disposing the first external electrode and the second external electrode close to each other.

[0040] The first to fourth external electrodes may each extend from the corresponding main surface along the bottom surface of the electrolytic capacitor. By extending the external electrodes to the bottom surface of the electrolytic capacitor, the anode terminal and / or the cathode terminal can be provided on the bottom surface of the electrolytic capacitor. In this case, the current flowing through the extending portion of the first external electrode flows in a direction opposite to the current flowing through the end portion of the anode body exposed on the first main surface, and the current flowing through the extending portion of the third external electrode flows in a direction opposite to the current flowing through the end portion of the anode body or the cathode portion exposed on the third main surface. Thereby, the magnetic field generated by the current flowing through each end portion is canceled by the magnetic field generated by the current flowing through the extending portion of the first or third external electrode, and the ESL of the electrolytic capacitor can be further reduced.

[0041] Similarly, the current flowing through the extending portion of the second external electrode flows in a direction opposite to the current flowing through the end portion of the cathode portion exposed on the second main surface, and the current flowing through the extending portion of the fourth external electrode flows in a direction opposite to the current flowing through the end portion of the cathode portion exposed on the fourth main surface. Thereby, the magnetic field generated by the current flowing through each end portion is canceled by the magnetic field generated by the current flowing through the extending portion of the second or fourth external electrode, and the ESL of the electrolytic capacitor can be further reduced.

[0042] In addition, due to the extending portion, the separation distance between the anode terminal (the first or third external electrode) and the cathode terminal (the second or fourth external electrode) can be made shorter, which is effective in improving the ESL. Due to these synergistic effects, the ESL can be significantly reduced.

[0043] In at least one of the first to fourth external electrodes, the external electrode may be configured to include a plurality of electrode portions spaced apart along the corresponding main surface. By having a plurality of terminals for the anode terminal or the cathode terminal, the ESL is further reduced. When having the third external electrode and including a plurality of electrode portions in at least one of the first external electrode and the third external electrode, the anode terminal has three or more terminals. When having the fourth external electrode and including a plurality of electrode portions in at least one of the second external electrode and the fourth external electrode, the cathode terminal has three or more terminals.

[0044] Hereinafter, the electrolytic capacitor and the method for manufacturing the same according to the present embodiment will be described in detail with reference to the drawings.

[0045] [First Embodiment] FIGS. 1A and 1B are cross-sectional views schematically showing the structure of the electrolytic capacitor according to the present embodiment. FIG. 1A is a cross-sectional view taken from a direction perpendicular to the stacking direction of the capacitor element and perpendicular to the first direction (X direction). FIG. 1B is a cross-sectional view taken from a direction perpendicular to the stacking direction of the capacitor element and perpendicular to the second direction (Y direction) intersecting the first direction. However, the electrolytic capacitor according to the present disclosure is not limited thereto.

[0046] As shown in FIGS. 1A and 1B, the electrolytic capacitor 100 includes an anode foil 10A as an anode body, a solid electrolyte layer 7, and a cathode foil 20A. The anode foil 10A and the cathode foil 20A are alternately stacked with the solid electrolyte layer 7 interposed therebetween. The solid electrolyte layer 7 constituting the cathode portion, and facing each other the solid electrolyte layer 7 sandwiched by One capacitor element 40 (first capacitor element) is formed by the anode foil 10A. The electrolytic capacitor 100 includes an element laminate including a plurality of capacitor elements 40 by laminating a plurality of anode foils 10A and solid electrolyte layers 7 via the cathode foil 20A. In the examples of FIGS. 1A and 1B, since there are four anode foils 10A and four cathode foils 20A, and one capacitor element is formed by one side of the anode foil facing each other and one side of the cathode portion (cathode foil), seven capacitor elements are formed. The element laminate is supported by a substrate 24. The substrate is, for example, an insulating substrate, and may be a metal substrate or a printed substrate provided with a wiring pattern as long as it can electrically separate between the external electrodes 50A, 50C and the external electrodes 50B, 50D. A cathode foil may be disposed between the solid electrolyte layer located at the lowermost surface of the element laminate and the substrate 24.

[0047] The anode foil 10A has a porous portion 5 on its surface, and a dielectric layer (not shown) is formed on at least a part of the surface of the porous portion 5. The solid electrolyte layer 7 covers at least a part of the dielectric layer.

[0048] As shown in FIG. 1A, the anode foil 10A has a region covered by the solid electrolyte layer 7 and a region not covered by the solid electrolyte layer 7. The anode foil 10A has a pair of first end portions 1a and 1b facing each other in the first direction (X direction), and the first end portions 1a and 1b are not covered by the solid electrolyte layer but are covered by the insulating film 8 instead. The region of the anode foil 10A not covered by the solid electrolyte layer (the first end portions 1a and 1b) is also called the anode lead-out portion. The region of the anode foil 10A covered by the solid electrolyte layer 7 is also called the cathode formation portion.

[0049] More specifically, the anode foil 10A has, in the cathode formation portion, a core portion 4 and a porous portion (porous body) 5 formed on the surface of the core portion 4 by roughening (such as etching). On the other hand, in the anode lead-out portion, it may or may not have a porous portion 5 on its surface. The dielectric layer is formed along the surface of the porous portion 5. At least a part of the dielectric layer covers the inner wall surface of the pores of the porous portion 5 and is formed along the inner wall surface. The surface of the dielectric layer has an uneven shape corresponding to the shape of the surface of the porous portion 5, and the solid electrolyte layer 7 can be formed so as to fill such unevenness of the dielectric layer.

[0050] An adhesive layer 23 is interposed between the cathode foil 20A and the solid electrolyte layer 7. The cathode foil 20A covers at least a part of the solid electrolyte layer 7 via the adhesive layer 23. The cathode foil 20A, the solid electrolyte layer 7, and the adhesive layer 23 constitute the cathode portion.

[0051] As shown in FIG. 1B, the cathode foil 20A has a region facing the solid electrolyte layer 7 and a region not facing the solid electrolyte layer 7. The cathode foil 20A has a pair of second end portions 2a and 2b facing each other in the second direction, and at the second end portions 2a and 2b, the cathode foil 20A is not covered by the solid electrolyte layer 7 and the surface of the cathode foil 20A is exposed.

[0052] The electrolytic capacitor 100 includes the above-described element laminate including a plurality of capacitor elements 40, an exterior body 30 that seals the element laminate, a first external electrode 50A, a second external electrode 50B, a third external electrode 50C, and a fourth external electrode 50D. The first external electrode 50A and the third external electrode 50C are anodes of the electrolytic capacitor 100, and the second external electrode 50B and the fourth external electrode 50D are cathodes of the electrolytic capacitor 100.

[0053] The exterior body 30 has a substantially rectangular parallelepiped outer shape, and the electrolytic capacitor 100 also has a substantially rectangular parallelepiped outer shape. The exterior body 30 has a first main surface 31A, a second main surface 31B that intersects the first main surface 31A, a third main surface 31C on the opposite side of the first main surface 31A, and a fourth main surface 31D on the opposite side of the second main surface 31B.

[0054] As shown in FIG. 1A, an end surface 3A (first end surface) of a first end portion 1a of the anode foil 10A is exposed from the exterior body 30 on the first main surface 31A and is electrically connected to the first external electrode 50A. Further, an end surface 3C (third end surface) of a first end portion 1b of the anode foil 10A is exposed from the exterior body 30 on the third main surface 31C and is electrically connected to the third external electrode 50C.

[0055] On the other hand, as shown in FIG. 1B, an end surface 3B (second end surface) of a second end portion 2a of the cathode foil 20A is exposed from the exterior body 30 on the second main surface 31B and is electrically connected to the second external electrode 50B. Further, an end surface 3D (fourth end surface) of a second end portion 2b of the cathode foil 20A is exposed from the exterior body 30 on the fourth main surface 31D and is electrically connected to the fourth external electrode 50D.

[0056] That is, in the electrolytic capacitor 100, each of the plurality of first end portions 1a, the plurality of first end portions 1b, the plurality of second end portions 2a, and the plurality of second end portions 2b exposed from the exterior body 30 is electrically connected to one of the external electrodes 50A to 50D extending along any one of the corresponding main surfaces 31A to 31D. In this case, in order to form the anode of the electrolytic capacitor, it is not necessary to bundle the plurality of first end portions, and it is not necessary to secure a length for bundling the plurality of first end portions. Therefore, compared with the case of bundling the plurality of first end portions, the ratio of the first end portions in the anode body can be reduced to increase the capacitance. Also, the contribution of the ESL by the first end portions is reduced. Further, since the anode (the first external electrode 50A and / or the third external electrode 50C) and the cathode (the second external electrode 50B and / or the fourth external electrode 50D) of the electrolytic capacitor are provided on main surfaces that cross each other, the separation distance between the external electrode of the anode and the external electrode of the cathode can be shortened, and the ESL can be reduced.

[0057] In the electrolytic capacitor 100, each of the end faces of the plurality of first end portions 1a, 1b exposed from the exterior body 30 and the end faces of the plurality of second end portions 2a, 2b is covered with a contact layer 51. An intermediate electrode layer 52 covers the contact layer 51 and each of the main surfaces 31A to 31D of the exterior body 30. The first to fourth external electrodes 50A to 50D each cover the corresponding intermediate electrode layer 52. Thereby, each of the end faces of the first end portions 1a, 1b and the second end portions 2a, 2b is electrically connected to one of the corresponding external electrodes 50A to 50D.

[0058] Each of the external electrodes 50A to 50D is bent along the bottom surface of the exterior body 30 and exposed on the bottom surface of the electrolytic capacitor 100. For example, a part of the third external electrode 50C is bent along the bottom surface of the exterior body 30 so as to face the bent portion of the first external electrode 50A and is exposed on the bottom surface of the electrolytic capacitor 100. The exposed portions on the bottom surfaces of the first external electrode 50A and the third external electrode 50C constitute the anode terminal of the electrolytic capacitor. On the other hand, the exposed portions on the bottom surfaces of the second external electrode 50B and the fourth external electrode 50D constitute the cathode terminal of the electrolytic capacitor. That is, in the present embodiment, the electrolytic capacitor 100 has two spaced-apart anode terminals and two spaced-apart cathode terminals. The anode terminal and the cathode terminal can be provided along the sides intersecting each other on the bottom surface of the electrolytic capacitor 100. In this case, compared with the conventional configuration in which the anode terminal and the cathode terminal are provided along the sides facing each other on the bottom surface of the electrolytic capacitor 100, the separation distance between the anode terminal and the cathode terminal can be shortened and the ESL can be reduced.

[0059] In the electrolytic capacitor 100 shown in FIG. 1A, on the third main surface 31C, the end portion 1b of the anode foil 10A is exposed and electrically connected to the third external electrode 50C on the end face 3C. However, on the third main surface 31C, the end portion of the cathode foil 20A may be exposed and electrically connected to the third external electrode 50C on the end face 3C. FIG. 1C shows a cross-sectional view of the electrolytic capacitor when the third external electrode 50C is electrically connected to the cathode portion of the electrolytic capacitor in the structure of the electrolytic capacitor shown in FIG. 1A. In this case, the electrolytic capacitor may have one anode terminal and three cathode terminals.

[0060] (Method for manufacturing an electrolytic capacitor) The method for manufacturing an electrolytic capacitor according to the present embodiment is a method for manufacturing an electrolytic capacitor including an element laminate including a plurality of capacitor elements each having an anode body having a porous portion on its surface, a dielectric layer formed on at least a part of the surface of the porous portion, and a cathode portion covering at least a part of the dielectric layer, and the manufacturing method includes a plurality of The element laminate is stacked layer side On a plane perpendicular to the arranged inThe step of obtaining the listed element assembly, and the element assembly in a plurality of element laminate The step of individualizing, electrically connecting the end of the anode body of the element laminate to the first external electrode, of the element laminate And the step of electrically connecting the end of the cathode part to the second external electrode.

[0061] The step of obtaining the element assembly has, for example, the following steps (i) to (vi): (i) The step of preparing an anode foil with a porous part formed on the surface, (ii) The step of forming a dielectric layer on the surface of the anode foil, (iii )positive Pole on the foil And the step of forming the first opening, (iv) The step of forming a solid electrolyte layer in the first region of the anode foil, (v) The step of preparing a cathode foil processed into a shape having a second region partially facing the first region, and (vi) The step of alternately laminating the anode foil and the cathode foil.

[0062] Step (v) can be performed independently of and in parallel with steps (i) to (iv). Step (iii) may be performed after step (i). Step (iv) may be performed after step (ii). Step (iii) may be performed before step (iv) or after step (iv).

[0063] The first region of the anode foil, and negative Pole foil second region The arrangement pattern of may have a periodic pattern in which the unit pattern is periodically repeated in at least one of the first direction and the second direction intersecting the first direction. The unit pattern of the first region may include a region A1 located in the center in the first direction and a region A2 extending from the region A1 in the first direction. The second region unit pattern May include a region A3 corresponding to the region A1 of the anode foil and a region A4 extending from the region A3 in the second direction.

[0064] Note that "extending in the first direction" means extending substantially parallel to the first direction, including both the case of extending in one direction parallel to the first direction starting from a certain region and the case of extending in the other direction parallel to the first direction (the direction opposite to one direction of the first direction). The same applies to "extending in the second direction".

[0065] In this embodiment, by overlapping an anode foil and a cathode foil that are pre-patterned into a predetermined shape, an assembly in which a plurality of laminate bodies of capacitor elements are periodically arranged on a plane perpendicular to the stacking direction is obtained. Then, the assembly is cut along a predetermined cutting plane parallel to the stacking direction to individualize a plurality of element laminate bodies. Thereby, the productivity in the manufacture of the electrolytic capacitor is improved.

[0066] FIG. 2A shows an example of the pattern of the anode foil for forming the element assembly in this embodiment. In FIG. 2A, the anode foil 10A has a pattern in which the anode pattern 11A is periodically repeated in the first direction (X direction) and the second direction (Y direction). FIG. 2A shows, as the anode pattern 11A, the pattern of the first opening 12A formed in step (iii) and the pattern of the solid electrolyte layer 7 and the insulating film (resist) 8 formed in step (iv). FIG. 2B is an enlarged view of the anode pattern 11A in FIG. 2A. In FIGS. 2A and 2B, regions outside both ends in the first direction (X direction) of the formation region (first region) of the solid electrolyte layer 7 in the anode pattern 11A constitute a pair of first ends facing each other in the first direction.

[0067] Further, FIG. 3A shows an example of the shape and arrangement pattern of the cathode foil for forming the element assembly in the present embodiment. In FIG. 3A, the cathode foil 20A has an arrangement pattern in which the cathode pattern 21A is periodically repeated in the first direction (X direction) and the second direction (Y direction), and is overlapped with the anode foil. FIG. 3B is an enlarged view of the cathode pattern 21A in FIG. 3A. In FIGS. 3A and 3B, the cathode foil 20A exists in the region 22A (second region). The regions other than the region 22A are cathode non-formation regions. Both ends of the cathode formation region (second region) in the second direction (Y direction) in the cathode pattern 21A constitute a pair of second ends facing each other in the second direction.

[0068] ( element Step of obtaining an assembly) Step (i) First, prepare an anode foil having a porous portion formed on its surface. The anode foil can include a valve action metal, an alloy containing a valve action metal, and a compound containing a valve action metal (such as an intermetallic compound). These materials can be used alone or in combination of two or more. As the valve action metal, aluminum, tantalum, niobium, titanium, etc. can be used. The anode foil may be a foil of a valve action metal, an alloy containing a valve action metal, or a compound containing a valve action metal, or may be a porous sintered body (sintered foil) of a valve action metal, an alloy containing a valve action metal, or a compound containing a valve action metal.

[0069] When a metal foil is used for the anode foil, usually, in order to increase the surface area, a porous portion is formed. The porous portion may be formed over the entire surface of the anode foil, or may be formed in a predetermined region of a part of the surface of the anode foil (for example, the formation region of the solid electrolyte layer in step (iv)). The porous portion may be formed by roughening the entire surface of the anode foil by etching or the like. It is also possible to perform a roughening process such as an etching process after disposing a masking member in a predetermined region on the surface of the anode foil. As the etching process, a known method may be used, and for example, electrolytic etching may be mentioned. The masking member is not particularly limited, but an insulator such as resin is preferable. The masking member needs to be removed before the formation of the solid electrolyte layer, but may be a conductive material.

[0070] In the region of the anode foil where the formation of the first end portion is planned, it is not necessary to form a porous portion. When a porous portion is formed at the first end portion, the adhesion between the porous portion and the exterior body is not sufficient, and air (specifically, oxygen and moisture) may enter the inside of the electrolytic capacitor through the contact portion between the porous portion and the exterior body. By not forming a porous portion at the first end portion, the adhesion between the anode foil and the exterior body can be maintained high, and the intrusion of air into the inside of the electrolytic capacitor through the porous portion from the first end portion exposed from the exterior body, and the decrease in the reliability of the electrolytic capacitor due to the intrusion of the air can be suppressed.

[0071] Step (ii) Next, a dielectric layer is formed on the surface of the anode foil. The dielectric layer is formed, for example, by anodizing a predetermined region including the region where the porous portion is formed on the surface of the anode foil by a forming process or the like. The dielectric layer contains an oxide of the valve action metal. For example, when aluminum is used as the valve action metal, the dielectric layer contains aluminum oxide. The dielectric layer is formed at least along the surface of the porous portion (including the inner wall surface of the pores of the porous portion). Note that the formation method of the dielectric layer is not limited to this, and an insulating layer that functions as a dielectric may be formed on the surface of the porous portion.

[0072] Step (iii) Next, a first opening 12A is formed in the region of the anode foil corresponding to the second end portion of the cathode portion. The first openings 12A are periodically arranged, for example, so as to intermittently extend in the second direction (Y direction) as shown in FIG. 2A. The first openings 12A can be arranged so as to sandwich the central region A1 in the anode pattern 11A as shown in FIG. 2B. The region A1 is also located at the center in the first direction (X direction).

[0073] Step (iv) Next, a solid electrolyte layer 7 is formed on the first region of the anode foil. At this time, an insulating film 8 may be formed on the regions other than the first region. In the present embodiment, the solid electrolyte layer 7 and the insulating film 8 are formed on both surfaces of the anode foil. The insulating film 8 is for preventing the solid electrolyte layer from being formed on a predetermined region (regions other than the first region) of the anode foil (a resist). The insulating film (resist) 8 can be formed, for example, by supplying a resin to a predetermined region of the anode foil by a method such as screen printing, inkjet, transfer, or tape attachment. As the resin material, insulating resins such as epoxy resin, phenol resin, silicone resin, melamine resin, urea resin, alkyd resin, polyurethane, polyamide, polyimide, polyamideimide, and unsaturated polyester can be used.

[0074] The resin material may contain the same resin as the resin used for the exterior body described later. However, the resin used for the insulating film preferably does not contain a filler or contains a filler having a smaller particle size than the filler contained in the resin used for the exterior body, in terms of facilitating impregnation of the liquid resin material into the deep portions of the recesses on the surface of the porous portion of the anode foil and easily forming a thin insulating film so that a plurality of capacitor elements can be stacked.

[0075] The solid electrolyte layer 7 contains, for example, a conductive polymer. As the conductive polymer, for example, polypyrrole, polythiophene, polyaniline, and their derivatives can be used. The solid electrolyte layer can be formed, for example, by applying a solution in which a conductive polymer is dissolved or a dispersion in which a conductive polymer is dispersed to the dielectric layer. The solid electrolyte layer 7 may contain a manganese compound.

[0076] For example, after forming the insulating film (resist) 8, a solid electrolyte layer 7 is formed in a region (first region 13A) where the insulating film (resist) 8 is not formed. The first region 13A includes, for example, a region A1 located at the center in the pattern 11A and a region A2 extending from the region A1 in the first direction (X direction), as shown in FIG. 2 B. The first region may also include a region A7 extending from the region A1 in the first direction on the side opposite to the region A2.

[0077] Since the region A1 is a region sandwiched by the first opening 12A, the extension width of the region A1 in the second direction is limited by the first opening 12A. On the other hand, since the regions A2 and A7 are not sandwiched by the first opening 12A in the second direction, the extension widths of the regions A2 and A7 in the second direction can be longer than the extension width of the region A1 in the second direction. Thereby, the facing area between the anode foil and the cathode foil can be increased, and a high capacitance can be obtained. In this case, the first region 13A, which is the formation region of the solid electrolyte layer 7, may have a recess recessed in the second direction along the edge of the first opening 12A.

[0078] Note that due to the formation of the first opening 12A, the end face of the anode foil is exposed at the edge of the first opening 12A, and the core portion of the anode foil is exposed at the end face. When forming the solid electrolyte layer 7 after forming the first opening 12A, an insulating layer may be formed on the end face of the anode foil exposed by the first opening 12A so that the exposed core portion is not covered by the solid electrolyte layer. The formation of the insulating film can be performed, for example, by subjecting the end face to a forming treatment to form an oxide film on the surface of the exposed core portion. However, the above-described insulating layer formation step is not necessarily required when the first region 13A is sufficiently separated from the edge of the first opening 12A via the insulating film 8, or when the first opening 12A is formed after forming the solid electrolyte layer 7.

[0079] In the examples of FIGS. 2A and 2B, a part of the edge of the first opening 12A is in contact with the first region 13A. In this case, after forming an insulating layer on the exposed end face and then forming a solid electrolyte layer, the solid electrolyte layer can adhere so as to cover the insulating layer. As a result, the solid electrolyte layers formed on both sides of the anode foil are electrically connected, and a plurality of capacitor elements in the element laminate can be electrically connected. Thereby, the ESR can be reduced.

[0080] Step (v) In parallel with steps (i) to (iv), a cathode foil 20A is prepared. The cathode foil 20A is processed into a shape having a second region 22A that partially faces the first region 13A. The cathode foil may be a conductive sheet, for example, a metal foil such as an aluminum foil. The metal foil may be a sintered foil, a vapor-deposited foil, or a coated foil having a conductive film on its surface. Examples of the conductive film include Ti, TiC, TiO, and a C (carbon) film. The conductive film may be a carbon coating film. The cathode foil 20A can be obtained, for example, by cutting a large-sized metal foil into a predetermined shape having the second region 22A.

[0081] As shown in FIG. 3B, the second region 22A may include a region A3 corresponding to the region A1 of the anode foil 10A, and may include a region A4 extending in the second direction (Y direction) from the region A3. The second region 22A may also include a region A5 extending in the first direction (X direction) from the region A3, and a region A8 extending in the first direction (X direction) from the region A3 on the side opposite to the region A5. In this case, at least a part of the region A5 overlaps with a region corresponding to the region A2 of the anode foil. Also, at least a part of the region A8 overlaps with a region corresponding to the region A7 of the anode foil.

[0082] Note that the region corresponding to the region of the anode foil means the region of the cathode foil that faces the region of the anode foil when the cathode foil 20A is overlapped with the anode foil 10A so that the contours of the anode pattern 11A and the cathode pattern 21A coincide.

[0083] Region A4 has a portion that protrudes in the second direction with respect to regions A5 and A8. The second region 22A may also include region A6 that extends in a direction opposite to the direction in which region A3 extends to region A4. In that case, region A6 may have a portion that protrudes in a direction opposite to the protruding direction of region A4 with respect to regions A5 and A8. In the example of FIG. 3A, in adjacent cathode patterns, the protruding portion of one region A4 and the protruding portion of the other region A6 are connected to form a strip-shaped second region 22A that extends in the second direction.

[0084] Step (vi) Subsequently, the anode foil and the cathode foil are alternately laminated. At this time, the anode foil 10A and the cathode foil 20A are alternately placed so that the contours of the anode pattern 11A and the cathode pattern 21A coincide, and an element assembly is obtained.

[0085] A layout diagram of the state where the cathode foil 20A is stacked on the anode foil 10A is shown in FIG. 4. As shown in FIG. 4, the extension distance in the first direction (X direction) of region A2 of the anode foil from region A1 is longer than the extension distance in the first direction of region A5 of the cathode foil from region A3. Also, the extension distance in the direction opposite to the first direction (X direction) of region A7 of the anode foil from region A1 is longer than the extension distance in the direction opposite to the first direction of region A8 of the cathode foil from region A3. Thereby, by cutting the element assembly along a straight line parallel to the second direction (Y direction) so as to straddle the region outside the first region 13A (that is, the region where the insulating film 8 is formed), the end face of the cathode foil is not exposed, and only the end face of the anode foil is exposed. The portions of the anode foil 10A located outside region A2 (farther from region A1) and the portions of the anode foil 10A located outside region A7 (farther from region A1) constitute a pair of first end portions. The exposed end face of the anode foil constitutes the first end face or the third end face.

[0086] Also, in a state where the anode foil 10A and the cathode foil 20A are overlapped, the protruding portions in the region A4 and the region A6 extend in the second direction (Y direction) above and below the first opening 12A. That is, the anode foil 10A does not exist above and below the protruding portions. Therefore, by cutting the element assembly along a straight line parallel to the first direction (X direction) so as to straddle the protruding portions, the end face of the anode foil is not exposed, and only the end face of the cathode foil is exposed. The end portions on the protruding direction side of the region A4 and the region A6 constitute a pair of second end portions. The exposed end face of the cathode foil constitutes the second end face or the fourth end face.

[0087] A conductive adhesive layer 23 such as a carbon paste or a silver paste may be interposed between the anode foil 10A and the cathode foil 20A.

[0088] In the step (iv), if the solid electrolyte layers 7 formed on both sides of the anode foil 10A are electrically connected via the solid electrolyte layer 7 and / or the conductive adhesive layer 23 formed on the end face of the anode foil 10A, when obtaining the element assembly by alternately stacking the anode foil 10A and the cathode foil 20A, the stacking of at least one cathode foil 20A may be omitted. (Step of separating the element assembly) Subsequently, the element assembly is cut along a plane perpendicular to the stacking direction to obtain an individualized element laminate. The step of separating the element assembly has, for example, the following steps (vii) to (viii): (vii) Step of filling the first opening of the anode foil of the element assembly and the second region of the cathode foil region other than with an exterior body, (viii) Step of cutting the element assembly with a cut line parallel to the second direction without straddling the first region and exposing the end face of the anode foil on the first main surface of the exterior body, and (ix) Step of cutting the element assembly with a cut line parallel to the first direction straddling the region A4 and exposing the end face of the cathode foil on the second main surface of the exterior body.

[0089] Step (vii) First, the element assembly is placed on a substrate. Then, the first opening 12A of the anode foil of the element assembly and the second region 22A of the cathode foilregion other than It is filled with the exterior body 30. The exterior body 30 preferably contains, for example, a cured product of a curable resin composition, and may also contain a thermoplastic resin or a composition containing the same.

[0090] The exterior body 30 can be formed using a molding technique such as injection molding. For example, the exterior body can be formed by filling a curable resin composition or a thermoplastic resin (composition) into a predetermined location so as to cover the element assembly using a predetermined mold.

[0091] The curable resin composition may contain, in addition to the curable resin, a filler, a curing agent, a polymerization initiator, and / or a catalyst, etc. Examples of the curable resin include epoxy resin, phenolic resin, urea resin, polyimide, polyamideimide, polyurethane, diallyl phthalate, unsaturated polyester, etc. Examples of the thermoplastic resin include polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), etc. A thermoplastic resin composition containing a thermoplastic resin and a filler may also be used.

[0092] As the filler, for example, insulating particles and / or fibers, etc. are preferable. Examples of the insulating material constituting the filler include insulating compounds (such as oxides) such as silica and alumina, glass, mineral materials (such as talc, mica, and clay), etc. The exterior body may contain one kind of these fillers, or may contain a combination of two or more kinds.

[0093] The resin used for the exterior body 30 may contain the same resin as the resin used for the above-mentioned insulating film 8 (resist). In this case, the adhesion between the insulating film and the exterior body is improved, and the intrusion of air into the electrolytic capacitor is further suppressed. Examples of the same resin contained in the insulating film and the exterior body include epoxy resin. On the other hand, the filler that may be contained in the exterior body may be different from the filler that may be contained in the insulating film.

[0094] Step (viii) Next, the element assembly with the gap filled by the exterior body is cut along a cut line that does not cross the first region 13A and is parallel to the second direction, exposing the end face of the anode foil on the first main surface of the exterior body. The cutting is performed, for example, by dicing. For example, by cutting the element assembly along the lines C1 and C2 shown in FIG. 4, the element assembly is separated in the first direction (X direction). In FIG. 4, the lines C1 and C2 can be straight lines parallel to the second direction (Y direction) that form the contour lines of the anode pattern 11A and the cathode pattern 21A.

[0095] At this time, on both sides of the separated element assembly piece in a plane parallel to the second direction, the end faces of the anode foil are exposed. One of the two sides where the end face of the anode foil is exposed is the first main surface, and the other is the third main surface. The end face of the anode foil exposed on the first main surface is the first end face. The end face of the anode foil exposed on the third main surface is the third end face.

[0096] Step (ix) Furthermore, the element assembly with the gap filled by the exterior body is cut along a cut line parallel to the first direction that crosses region A4, exposing the end face of the cathode foil on the second main surface of the exterior body. The cutting is performed, for example, by dicing. For example, by cutting the element assembly along the lines D1 and D2 shown in FIG. 4, the element assembly is separated in the second direction (Y direction). In FIG. 4, the lines D1 and D2 can be straight lines parallel to the first direction (X direction) that form the contour lines of the anode pattern 11A and the cathode pattern 21A.

[0097] At this time, on both sides of the separated element assembly piece in a plane parallel to the first direction, the end faces of the cathode foil are exposed. One of the two sides where the end face of the cathode foil is exposed is the second main surface, and the other is the fourth main surface. The end face of the cathode foil exposed on the second main surface is the second end face. The end face of the cathode foil exposed on the fourth main surface is the fourth end face.

[0098] By step (viii) and step (ix), the element assembly is separated, and the element assembly is individualized into a plurality of element laminate bodies. (Connection step of external electrodes) Next, the end faces of the exposed anode foil and cathode foil are electrically connected to the external electrodes.

[0099] In this step, for example, the first external electrode 50A is formed so as to cover a predetermined region of the first main surface 31A of the exterior body, and the first end face 3A of the anode foil is covered with the first external electrode 50A, thereby electrically connecting the first external electrode 50A to the first end face 3A. Similarly, the second external electrode 50B is formed so as to cover a predetermined region of the second main surface 31B of the exterior body, and the second end face 3B of the cathode foil is covered with the second external electrode 50B, thereby electrically connecting the second external electrode 50B to the second end face 3B.

[0100] When the anode foil has a third end face 3C, the third external electrode 50C may be electrically connected to the third end face 3C. The third external electrode 50C is formed so as to cover a predetermined region of the third main surface 31C of the exterior body. By forming the third external electrode 50C so as to cover the third end face 3C of the anode foil, the third external electrode 50C is electrically connected to the third end face 3C.

[0101] Similarly, when the cathode foil has a fourth end face 3D, the fourth external electrode 50D may be electrically connected to the fourth end face 3D. The fourth external electrode 50D is formed so as to cover a predetermined region of the fourth main surface 31D of the exterior body. By forming the fourth external electrode 50D so as to cover the fourth end face 3D of the cathode foil, the fourth external electrode 50D is electrically connected to the fourth end face 3D.

[0102] The electrical connection between each of the first to fourth end faces and the corresponding external electrode may be performed by bonding or the like, or may be performed using an electrolytic plating method, electroless plating method, physical vapor deposition method, chemical vapor deposition method, cold spray method, and / or thermal spraying method. Among them, the electroless plating method is preferable.

[0103] The first to fourth external electrodes are preferably metal layers. The metal layer may contain at least one selected from the group consisting of, for example, nickel (Ni), copper (Cu), zinc (Zn), tin (Sn), silver (Ag), and gold (Au).

[0104] The first to fourth external electrodes may have, for example, a laminated structure of a Ni layer and a tin layer. The first to fourth external electrodes only need to be made of a metal with excellent wettability to solder at least on their outer surfaces. Examples of such metals include Sn, Au, Ag, Pd, and the like.

[0105] Prior to forming the first to fourth external electrodes 50A to 50D, a step of forming a contact layer 51 on the corresponding end faces of the external electrodes and / or a step of forming an intermediate electrode layer 52 covering a predetermined region of the corresponding main surface of the exterior body may be performed. When forming the intermediate electrode layer 52, the first to fourth external electrodes may be formed so as to cover the corresponding intermediate electrode layer.

[0106] When forming the intermediate electrode layer, the first to fourth external electrodes may be formed by adhering a Cu cap with a pre-formed Sn film to the intermediate electrode layer.

[0107] (Step of forming the contact layer) The contact layer 51 can be formed by, for example, methods such as cold spray method, thermal spraying, plating, vapor deposition, etc. The contact layer may be formed so as not to cover the main surface of the exterior body as much as possible and selectively cover the end faces of the anode foil or cathode foil exposed from the exterior body.

[0108] Among them, the cold spray method is a technique of accelerating metal particles with a size of several μm to several tens of μm from subsonic speed to supersonic speed by compressed gases such as air, nitrogen, and helium, and colliding them with a substrate in a solid state to form a metal film. Regarding the adhesion mechanism of metal particles in the cold spray method, although there are still some parts that have not been clarified, generally, it is considered that due to the collision energy of metal particles, the metal particles or the metal substrate undergo plastic deformation, and new surfaces are exposed on the metal surface, thereby activating.

[0109] When using the cold spray method, the contact layer is formed by causing metal particles to collide with each end face at high speed. By using the cold spray method, it is possible to realize a state where metal particles are difficult to adhere to the resin base material and selectively form the contact layer on the first to fourth end faces. In this case, the resin base material undergoes brittle fracture due to the collision energy of the metal particles, and the surface of the resin base material is scraped off. Therefore, the contact layer can be selectively formed on the first to fourth end faces, and the corresponding main surface of the exterior body can be roughened. Since the main surface of the exterior body is roughened, the contact area between the exterior body and the external electrode (or the intermediate electrode) increases, and the adhesion between the exterior body and the external electrode (or the intermediate electrode) is improved by the anchor effect. As a result, the reliability can be further enhanced.

[0110] The metal particles may be particles of a metal with a lower ionization tendency than the metal constituting the anode body. For example, when the anode body is an Al foil, Cu particles can be cited as such metal particles. In this case, the Cu particles that have collided with the end face of the first end portion at high speed can break through the natural oxide film (Al oxide film) formed on the end face, and a metal bond between Al and Cu can be formed. As a result, an alloy layer of Al and Cu can be formed at the interface between the contact layer and the first end portion. On the other hand, the surface of the contact layer is covered with a Cu layer that is a non-valve action metal. Since Cu has a lower ionization tendency than Al, the surface of the contact layer is hardly oxidized, and an electrical connection with the external electrode (or the anode electrode layer) can be surely made.

[0111] (Step of forming the intermediate electrode layer) The intermediate electrode layer 52 can be formed so as to cover any one of the first to fourth end faces or the contact layer and cover the corresponding main surface of the exterior body.

[0112] The intermediate electrode layer may be formed by applying a conductive paste containing conductive particles and a resin material. Specifically, a conductive paste (for example, a silver paste) is applied to each end face by a dipping method, a transfer method, a printing method, a dispensing method, etc., and then cured at a high temperature to form the intermediate electrode layer.

[0113] Alternatively, an intermediate electrode layer, which is a metal layer, may be formed by an electrolytic plating method, an electroless plating method, a sputtering method, a vacuum evaporation method, a chemical vapor deposition (CVD) method, a cold spray method, or a thermal spraying method.

[0114] The intermediate electrode layer may cover a part of a surface (for example, the upper surface or the bottom surface) orthogonal to the first to fourth main surfaces of the exterior body.

[0115] By the above manufacturing method, the electrolytic capacitor shown in FIGS. 1A and 1B can be manufactured. Note that FIG. 1A corresponds to a cross-sectional view taken along line X1-X2 of FIG. 4, and FIG. 1B corresponds to a cross-sectional view taken along line Y1-Y2 of FIG. 4.

[0116] In the above embodiment, a plurality of cathode foils 20A processed into a shape having a strip-shaped second region 22A extending in the second direction are arranged in the first direction and placed on the anode foil 10A to create an element assembly. However, the second region 22A may have a portion connecting the strip-shaped regions. In this case, it is easy to position and overlap the cathode foil having the second region with respect to the anode foil to obtain an element assembly, and productivity can be improved.

[0117] FIG. 5 shows another example of the arrangement pattern of the cathode foil. In the cathode pattern 21B shown in FIG. 5, a connection region A9 connecting the second regions 22B arranged in the first direction is provided between the region A4 and the region A6. In step (ix), by cutting the element assembly along lines D3 to D6, the connection region A9 is removed, and the end faces of the cathode foil are exposed in the regions A4 and A6. One of the exposed end faces becomes the second end face, and the other becomes the fourth end face.

[0118] Further, in the above-described embodiment, in step (ix), when the element assembly is cut along lines D1 and D2 shown in FIG. 4, the end faces of the cathode foil are exposed on the second main surface and the fourth main surface of the exterior body, and the end faces of the anode foil may be exposed on the first main surface side or the third main surface side of the second main surface and the fourth main surface. In order to insulate the end faces of the anode foil exposed on the second main surface and the fourth main surface, a formation treatment may be performed on the end faces. Alternatively, an element assembly may be obtained using the anode foil 10B shown in FIG. 6. In the anode pattern 11B shown in FIG. 6, the first opening 12B extends in the first direction outside the region A2 or the region A7. In step (ix), by cutting the element assembly along lines D1 and D2 so as to straddle the portion of the first opening 12B extending in the first direction, it is possible to limit the exposure of the end faces of the anode foil on the second main surface and the fourth main surface.

[0119] [Second Embodiment] In the method for manufacturing an electrolytic capacitor according to the present embodiment, in the step of obtaining an element assembly, a second opening extending in the second direction is formed in a first pattern to obtain a first anode foil, and the second opening is formed in a second pattern different from the first pattern to obtain a second anode foil.

[0120] FIGS. 7A and 7B show an example of the pattern of the anode foil for forming an element assembly in the present embodiment. In FIG. 7A, the anode foil 10C has a pattern in which the anode pattern 11C is periodically repeated in the first direction (X direction) and the second direction (Y direction). In FIG. 7B, the anode foil 10D has a pattern in which the anode pattern 11D is periodically repeated in the first direction (X direction) and the second direction (Y direction). FIGS. 7A and 7B show the pattern of the first opening 12A formed in step (iii) and the pattern of the solid electrolyte layer 7 and the insulating film (resist) 8 formed in step (iv). These patterns are the same as the patterns of the first opening 12A, the solid electrolyte layer 7, and the insulating film (resist) 8 in FIG. 2A, and detailed description thereof is omitted.

[0121] As shown in Fig. 7A, the second opening 14A is disposed in the anode pattern 11C. The second opening 14A extends in the second direction in the anode pattern 11C in a region outside the first region 13A on the side opposite to the region A1 with the region A2 interposed therebetween, or in a region outside the first region 13A on the side opposite to the region A1 with the region A7 interposed therebetween.

[0122] As shown in Fig. 7B, the second opening 14B is disposed in the anode pattern 11D. The second opening 14A also extends in the second direction in the anode pattern 11D, similarly to the anode pattern 11C, in a region outside the first region 13A on the side opposite to the region A1 with the region A2 interposed therebetween, or in a region outside the first region 13A on the side opposite to the region A1 with the region A7 interposed therebetween. However, the second opening 14B is not formed in the region of the anode foil 10D where the second opening 14A is formed in the anode foil 10C, and is formed in a region where the second opening 14A is not formed in the anode foil 10C. region corresponding to and is formed in a region where the second opening 14A is not formed in the anode foil 10C. to the corresponding region is formed.

[0123] When using the anode foil 10C or 10D, the singulation of the element assembly can be performed by cutting the element assembly with a cut line parallel to the second direction so as to straddle the region where the second opening 14A and / or 14B is formed (step (viii)). In this case, second opening 14A or 14B formed region on the side where it is formed, the end face of the anode foil does not expose from the exterior body. Therefore, the end face of the anode foil exposes only on one of the first main face or the third main face of the exterior body, and is electrically connected to the external electrode.

[0124] For example, in step (vi), the anode foils and the cathode foils are alternately laminated in the order of anode foil 10C, cathode foil 20A, anode foil 10D, and cathode foil 20A to obtain an element assembly. With respect to the obtained element assembly, in step (viii), the element assembly is cut along cutting lines C3 and C4 parallel to the second direction so as to straddle the regions where the second openings 14A and 14B are formed. In this case, in the element laminate obtained after individualization, the anode foil (the first anode foil) with an end face exposed only on the first main surface of the exterior body and the anode foil (the second anode foil) with an end face exposed only on the third main surface of the exterior body are alternately laminated via the cathode foil.

[0125] The second openings 14A and / or 14B may be formed to extend in the first direction so as to straddle region A2 and / or region A7. However, from the viewpoint of maintaining the capacitance, it is preferable that the second openings 14A and / or 14B are not formed in the region corresponding to the second region 22A of the cathode foil. That is, it is preferable that the second openings 14A and / or 14B do not overlap with the region corresponding to the end portion in the first direction of region A5 or region A8 of the cathode foil.

[0126] In the examples of FIGS. 7A and 7B, when the pattern of the second opening 14A in the anode foil 10C is rotated 180 degrees (or the front and back are reversed), it coincides with the pattern of the second opening 14B in the anode foil 10D. Therefore, the anode foil 10C (the first anode foil) coincides with the anode foil 10D (the second anode foil) by being rotated 180 degrees. Accordingly, it is not necessary to separately manufacture the anode foil 10C and the anode foil 10D. Two sets of the same anode foil can be prepared, one set is used as the first anode foil, and the other set is rotated 180 degrees (or the front and back are reversed) and used as the second anode foil.

[0127] FIGS. 8A and 8B are cross-sectional views schematically showing the structure of the electrolytic capacitor 101 manufactured in this way. Note that FIG. 8A corresponds to a cross-sectional view taken along line X1-X2 in FIGS. 7A and 7B, and FIG. 8B corresponds to a cross-sectional view taken along line Y1-Y2 in FIGS. 7A and 7B.

[0128] The electrolytic capacitor 101 includes an anode foil 10C and 10D which are anode bodies, a solid electrolyte layer 7, and a cathode foil 20A, similar to the electrolytic capacitor 100 of the first embodiment shown in FIGS. 1A and 1B. The anode foil and the cathode foil are alternately laminated with the solid electrolyte layer interposed therebetween. Further, the anode foil 10C and the anode foil 10D are alternately laminated with the cathode foil 20A and the solid electrolyte layer 7 interposed therebetween.

[0129] As shown in FIG. 8A, one end face 3A of one of the pair of first ends 1a of the anode foil 10C is covered by the exterior body 30, and the end face of the anode foil 10C is not exposed on the first main surface 31A of the exterior body 30. On the other hand, the end face 3C of the other of the pair of first ends 1b of the anode foil 10C is exposed from the exterior body 30 on the third main surface 31C of the exterior body 30, and is electrically connected to the external electrode 50C via the contact layer 51 and the intermediate electrode layer 52.

[0130] In contrast, one end face of one of the pair of first ends 1a of the anode foil 10D is exposed from the exterior body 30 on the first main surface 31A of the exterior body 30, and is electrically connected to the external electrode 50A via the contact layer 51 and the intermediate electrode layer 52. On the other hand, the end face of the other of the pair of first ends 1b of the anode foil 10D is covered by the exterior body 30, and the end face of the anode foil 10D is not exposed on the third main surface 31C of the exterior body 30.

[0131] One capacitor element 40A (first capacitor element) is constituted by the anode foil 10D, the solid electrolyte layer 7, and the cathode foil 20A facing the anode foil 10D with the solid electrolyte layer 7 interposed therebetween. On the other hand, one capacitor element 40B (second capacitor element) is also constituted by the anode foil 10C, the solid electrolyte layer 7, and the cathode foil 20A facing the anode foil 10C with the solid electrolyte layer 7 interposed therebetween.

[0132] The current flowing through the anode foil of the capacitor element 40A and the capacitor element 40B is opposite in the first direction (X direction). Therefore, the magnetic field generated by the current flowing through the first capacitor element 40A and the magnetic field generated by the current flowing through the second capacitor element 40B cancel each other out in the first direction, and the magnetic flux generated in the electrolytic capacitor 101 decreases. As a result, the ESL is reduced.

[0133] In FIGS. 8A and 8B, the anode foil and the cathode foil are alternately laminated with the solid electrolyte layer interposed therebetween, but they do not necessarily have to be alternately laminated. As long as an anode foil that is exposed on the first main surface 31A and not exposed on the third main surface 31C and an anode foil that is exposed on the third main surface 31C and not exposed on the first main surface 31A are laminated.

[0134] [Third Embodiment] The method for manufacturing an electrolytic capacitor according to the present embodiment further includes a step of obtaining a first cathode foil in which region A4 extends from region A3 in one direction of the second direction, and a step of obtaining a second cathode foil in which region A4 extends from region A3 in the other direction of the second direction. In step (vi), the anode foil, the first cathode foil, the anode foil, and the second cathode foil are laminated in this order to obtain an element assembly.

[0135] FIGS. 9A and 9B show an example of the shape and arrangement pattern of the cathode foil for forming the element assembly in the present embodiment. In FIG. 9A, the cathode foil 20C (first cathode foil) has an arrangement pattern in which the cathode pattern 21C is periodically repeated in the first direction (X direction) and the second direction (Y direction), and is overlapped with the anode foil. Further, in FIG. 9B, the cathode foil 20D (second cathode foil) has an arrangement pattern in which the cathode pattern 21D is periodically repeated in the first direction (X direction) and the second direction (Y direction), and is overlapped with the anode foil.

[0136] In FIG. 9A, the cathode foil 20C is present in the region 22C (second region). In the cathode pattern 21C, the region 22C has region A4 protruding from region A3 in one direction of the second direction. On the other hand, in the cathode pattern 21C, the region 22C does not protrude in the other direction of the second direction.

[0137] In FIG. 9B, the cathode foil 20D is present in the region 22D (second region). In the cathode pattern 21D, the region A4 protrudes from the region A3 in the other direction of the second direction in the region 22D. On the other hand, in the cathode pattern 21D, the region 22D does not protrude in one direction of the second direction. That is, both the region 22C and the region 22D have the region A4 protruding from the region A3 in the second direction, but the protruding directions are opposite.

[0138] For example, in step (vi), the anode foil and the cathode foil are alternately laminated in the order of the anode foil 10A, the cathode foil 20C, the anode foil 10A, and the cathode foil 20D to obtain an element assembly. For the obtained element assembly, in step (ix), it is cut along a straight line parallel to the first direction (X direction) to individualize the element assembly. The cutting line is, for example, a straight line extending in the first direction that constitutes the contour lines of the cathode pattern 21C and the cathode pattern 21D. In this case, in the element laminate obtained after individualization, the cathode foil (first cathode foil) with the end face exposed only on the second main surface of the exterior body and the cathode foil (second cathode foil) with the end face exposed only on the fourth main surface of the exterior body are alternately laminated via the anode foil.

[0139] The cathode foil 20C may have a region A6 extending from the region A3 in the other direction of the second direction. In that case, in step (ix), so that only one of the second main surface or the fourth main surface has the end face of the cathode foil 20C exposed, the extension distance L4 of the region A6 from the region A3 in one direction of the second direction is made shorter than the extension distance L1 of the region A4 from the region A3 in one direction of the second direction. Similarly, the cathode foil 20D may have a region A6 extending from the region A3 in one direction of the second direction. In that case, in step (ix), so that only one of the second main surface or the fourth main surface has the end face of the cathode foil 20D exposed, the extension distance L4 of the region A6 from the region A3 in one direction of the second direction is made shorter than the extension distance L3 of the region A4 from the region A3 in the other direction of the second direction.

[0140] FIG. 10A and FIG. 10B are cross-sectional views schematically showing the structure of the electrolytic capacitor 102 manufactured in this way. Note that FIG. 10A corresponds to the cross-sectional view taken along the line X1-X2 of FIGS. 9A and 9B, and FIG. 10B corresponds to the cross-sectional view taken along the line Y1-Y2 of FIGS. 9A and 9B.

[0141] The electrolytic capacitor 102 includes an anode foil 10A as an anode body, a solid electrolyte layer 7, and cathode foils 20C and 20D, similar to the electrolytic capacitor 100 of the first embodiment shown in FIGS. 1A and 1B. The anode foil and the cathode foils are alternately laminated with the solid electrolyte layer interposed therebetween. Further, the cathode foil 20C and the cathode foil 20D are alternately laminated with the anode foil 10A and the solid electrolyte layer 7 interposed therebetween.

[0142] As shown in FIG. 10B, one end face 3B of one of the pair of second ends 2a of the cathode foil 20C is exposed from the exterior body 30 on the second main surface 31B of the exterior body 30, and is electrically connected to the external electrode 50B through the contact layer 51 and the intermediate electrode layer 52. On the other hand, the other end face 3D of the other of the pair of second ends 2b of the cathode foil 20C is covered by the exterior body 30, and the end face of the cathode foil 20C is not exposed on the fourth main surface 31D of the exterior body 30.

[0143] In contrast, one end face of one of the pair of second ends 2a of the cathode foil 20D is covered by the exterior body 30, and the end face of the cathode foil 20D is not exposed on the second main surface 31B of the exterior body 30. On the other hand, the other end face of the other of the pair of second ends 2b of the cathode foil 20D is exposed from the exterior body 30 on the fourth main surface 31D of the exterior body 30, and is electrically connected to the external electrode 50D through the contact layer 51 and the intermediate electrode layer 52.

[0144] The anode foil 10A, the solid electrolyte layer 7, and the cathode foil 20C facing the anode foil 10A with the solid electrolyte layer 7 interposed therebetween constitute one capacitor element 40A (the first capacitor element). On the other hand, the anode foil 10A, the solid electrolyte layer 7, and the cathode foil 20D facing the anode foil 10A with the solid electrolyte layer 7 interposed therebetween also constitute one capacitor element 40C (the third capacitor element).

[0145] The capacitor element 40A and the capacitor element 40C are such that cathode the direction of the current flowing through the foil is reversed in the second direction (Y direction). For this reason, the magnetic field generated by the current flowing through the first capacitor element 40A and the magnetic field generated by the current flowing through the third capacitor element 40C cancel each other out in the second direction, and the magnetic flux generated in the electrolytic capacitor 102 decreases. As a result, the ESL is reduced.

[0146] [Fourth Embodiment] FIGS. 11A and 11B show another configuration example of the electrolytic capacitor according to this embodiment. FIGS. 11A and 11B are cross-sectional views schematically showing the structure of the electrolytic capacitor 103 according to this embodiment. The electrolytic capacitor 103 is manufactured by alternately laminating an anode foil 10E having an anode pattern 11E shown in FIG. 12 and a cathode foil 20E having a cathode pattern 21E shown in FIG. 13 to obtain an element laminate. In FIG. 12, the anode pattern 11E includes a first opening 12E, a first region 13E where the solid electrolyte layer 7 is formed, and a pattern of an insulating film (resist) 8. FIG. 11A corresponds to a cross-sectional view taken along the X1-X2 line of FIG. 12, and FIG. 11B corresponds to a cross-sectional view taken along the Y1-Y2 line of FIG. 13.

[0147] As shown in FIGS. 11A and 11B, the electrolytic capacitor 103 includes an anode foil 10E that is an anode body, a solid electrolyte layer 7, and a cathode foil 20E. The anode foil 10E and the cathode foil 20E are alternately laminated with the solid electrolyte layer 7 interposed therebetween. One capacitor element 40 (first capacitor element) is constituted by the solid electrolyte layer 7 and the anode foil 10E and the cathode foil 20E that face each other with the solid electrolyte layer 7 interposed therebetween. The electrolytic capacitor 103 includes an element laminate including a plurality of capacitor elements 40 by laminating a plurality of anode foils 10E and solid electrolyte layers 7 via the cathode foil 20E. The element laminate is supported by a substrate 24. The electrolytic capacitor 103 has a substantially rectangular parallelepiped outer shape, and the separation distance between the first main surface 31A and the third main surface 31C is longer than the separation distance between the second main surface 31B and the fourth main surface 31D.

[0148] As shown in FIG. 11A, the anode foil 10E has a region covered by the solid electrolyte layer 7 and a region not covered by the solid electrolyte layer 7. At the end of the region not covered by the solid electrolyte layer 7 (anode lead-out portion) of the anode foil 10E, it is exposed on the first main surface 31A of the exterior body 30 and is electrically connected to the first external electrode 50A via the contact layer 51 and the intermediate electrode layer 52.

[0149] On the other hand, at the end of the cathode foil 20E, it is exposed on the second main surface 31B, the third main surface 31C, and the fourth main surface 31D of the exterior body 30. The exposed ends are electrically connected to the second external electrode 50B, the third external electrode 50C, and the fourth external electrode 50D via the contact layer 51 and the intermediate electrode layer 52, respectively. That is, in this embodiment, the first external electrode 50A is the anode electrode of the electrolytic capacitor 103, and the second external electrode 50B, the third external electrode 50C, and the fourth external electrode 50D are the cathode electrodes of the electrolytic capacitor 103.

[0150] In the electrolytic capacitor 103, the end faces of the cathode foil exposed from the exterior body on the second main surface 31B and the fourth main surface 31D are located closer to the first main surface 31A than the third main surface 31C. For this reason, as shown in FIG. 11A, the distance between the first external electrode 50A and the second external electrode 50B is shorter than the distance between the third external electrode 50C and the second external electrode 50B. Similarly, the distance between the first external electrode 50A and the fourth external electrode 50D is shorter than the distance between the third external electrode 50C and the fourth external electrode 50D.

[0151] In this embodiment, by arranging the second external electrode 50B and the fourth external electrode 50D, which are the cathode electrodes, closer to the first external electrode 50A, which is the anode electrode, the ESL of the electrolytic capacitor can be further reduced. The second external electrode 50B and the fourth external electrode 50D may be continuous at the bottom of the electrolytic capacitor 103 and may constitute one external electrode as a whole.

[0152] The third external electrode 50C may not be electrically connected to the end of the cathode foil. That is, the end of the cathode foil may not have its end face exposed on the third main surface 31C of the exterior body 30. When neither the end of the anode foil nor the end of the cathode foil has its end face exposed on the third main surface 31C of the exterior body 30, it is not necessary to dispose the third external electrode 50C along the third main surface 31C. However, from the viewpoint of stably fixing the electrolytic capacitor to an external circuit board and suppressing disconnection due to shock or vibration, the third external electrode 50C may be disposed on at least the bottom surface on the third main surface 31C side of the electrolytic capacitor 103. In this case, although it does not contribute to electrical connection, by fixing the third external electrode 50C on the bottom surface to the external circuit board, the electrolytic capacitor can be stably fixed to the external circuit board against shock and vibration. FIG. 11C shows a cross-sectional view of the electrolytic capacitor in the case where the third external electrode 50C is a dummy electrode in the structure of the electrolytic capacitor shown in FIG. 11A.

[0153] [Fifth Embodiment] FIG. 14 shows an example of the patterns of the first external electrode 50A, the second external electrode 50B, the third external electrode 50C, and the fourth external electrode 50D formed on the surface of the electrolytic capacitor.

[0154] FIG. 14 is an example of the pattern of the external electrodes formed on an electrolytic capacitor 104 having the same structure as the electrolytic capacitor shown in FIGS. 1A, 1B, or 1C. In FIG. 14, (A) shows the pattern on the right side surface (the fourth main surface 31D) of the electrolytic capacitor 104, (B) shows the pattern on the upper surface of the electrolytic capacitor 104, (C) shows the pattern on the left side surface (the second main surface 31B) of the electrolytic capacitor 104, and (D) shows the pattern on the lower surface of the electrolytic capacitor 104. FIG. 15 is a perspective view schematically showing the appearance of the electrolytic capacitor of FIG. 14.

[0155] The shorter the separation distance D1 between the first external electrode 50A and the second external electrode 50B (the fourth external electrode 50D) on the side surface, and the separation distance D2 between the third external electrode 50C and the second external electrode 50B (the fourth external electrode 50D) on the side surface, the more the ESL can be reduced. The separation distances D1 and D2 may be, for example, from 0.4 mm to 1.1 mm.

[0156] As shown in FIGS. 14 and 15, the second external electrode 50B may be formed so as to cover 50% or more of the side surface (the second main surface 31B), and the fourth external electrode 50D may be formed so as to cover 50% or more of the side surface (the fourth main surface 31D). Also, on the lower surface (bottom surface) of the electrolytic capacitor, the second external electrode 50B and the fourth external electrode 50D may be continuous and may constitute one cathode terminal as a whole.

[0157] FIGS. 16 to 18 show another example of the patterns of the first external electrode 50A, the second external electrode 50B, the third external electrode 50C, and the fourth external electrode 50D formed on the surface of the electrolytic capacitor. In FIGS. 16 to 18, similar to FIG. 14, (A) shows the pattern on the right side surface (the fourth main surface 31D) of the electrolytic capacitor, (B) shows the pattern on the upper surface of the electrolytic capacitor, (C) shows the pattern on the left side surface (the second main surface 31B) of the electrolytic capacitor, and (D) shows the pattern on the lower surface of the electrolytic capacitor.

[0158] As shown in FIGS. 16 and 18, the second external electrode 50B and the fourth external electrode 50D may not be connected on the lower surface (bottom surface) and may form two separate cathode terminals.

[0159] FIG. 19 is a perspective view showing the appearance of the electrolytic capacitor of FIG. 17 or FIG. 18. As shown in FIG. 19, the first external electrode 50A does not cover the first main surface 31A of the exterior body, but covers a part of the second main surface 31B and the first main surface 31A side of the fourth main surface 31D. Similarly, the third external electrode 50C does not cover the third main surface 31C of the exterior body, but covers a part of the second main surface 31B and the third main surface 31C side of the fourth main surface 31D. The first external electrode 50A is electrically connected to the end of the capacitor element on the second main surface 31B and the fourth main surface 31D. The third external electrode 50C is electrically connected to the end of the capacitor element on the second main surface 31B and the fourth main surface 31D.

[0160] To reduce the ESL, a plurality of second external electrodes 50B and / or fourth external electrodes 50D may be arranged on the bottom surface and / or side surface. In this case, at least one of the second external electrodes 50B and / or the fourth external electrodes 50D may be arranged close to the first external electrode 50A, and at least one of the others may be arranged close to the third external electrode 50C. Thereby, the ESL can be effectively reduced. The minimum value D1 of the separation distance between the first external electrode 50A and the second external electrode 50B (the fourth external electrode 50D), and the minimum value D2 of the separation distance between the third external electrode 50C and the second external electrode 50B (the fourth external electrode 50D) may be, for example, 0.4 mm to 1.1 mm.

[0161] FIGS. 20 to 23 show an example of the patterns of the first external electrode 50A, the second external electrode 50B, the third external electrode 50C, and the fourth external electrode 50D formed on the surface of the electrolytic capacitor having a plurality of second external electrodes and fourth external electrodes. FIGS. 20 to 23 are respectively configured such that in FIGS. 14 and 16 to 18, the second external electrode 50B and the fourth external electrode 50D extending in the direction from the first main surface 31A to the third main surface 31C are each divided in that direction, one is arranged close to the first external electrode 50A, and the other is arranged close to the third external electrode 50C.

[0162] For the structures of the electrolytic capacitor 101 shown in FIGS. 8A and 8B and the electrolytic capacitor 102 shown in FIGS. 10A and 10B, the external electrode 50A to 50D shown in FIGS. 14 to 23 can be adopted for their appearance shapes.

Industrial Applicability

[0163] The electrolytic capacitor according to the present disclosure has a high capacitance and can be used in various applications that require low ESL.

Explanation of Signs

[0164] 10A to 10D: Anode foil 1a, 1b: First end 2a, 2b: Second end 3A to 3D: End face 4: Core 5: Porous part 7: Solid electrolyte layer 8: Insulating film (resist) 11A: Unit pattern of anode foil 12A, 12B, 12E: First opening 13A, 13E: First region (formation region of solid electrolyte layer) 14A, 14B: Second opening 20A to 20D: Cathode foil 21A to 21D: Arrangement pattern of cathode foil 22A to 22D: Second region 23: Adhesive layer 24: Substrate 30: Package 31A: First main surface of package 31B: Second main surface of package 31C: Third main surface of package 31D: Fourth main surface of package 40, 40A: Capacitor element (first capacitor element) 40B: Second capacitor element 40C: Third capacitor element 50A: First external electrode 50B: Second external electrode 50C: Third external electrode 50D: Fourth external electrode 51: Contact layer 52: Intermediate electrode layer 100~104: Electrolytic capacitor

Claims

1. An element laminate including a plurality of capacitor elements, an exterior body that seals the element laminate, a first external electrode, and a second external electrode, and each of the plurality of capacitor elements includes an anode body having a porous portion on a surface thereof, a dielectric layer formed on at least a part of a surface of the porous portion, and a cathode portion covering at least a part of the dielectric layer, and the exterior body has a first main surface, a second main surface intersecting with the first main surface, a third main surface on the opposite side of the first main surface, and a fourth main surface on the opposite side of the second main surface, among the plurality of capacitor elements, at least one first capacitor element has an end face of an end portion of the anode body exposed from the exterior body at least on the first main surface and electrically connected to the first external electrode, and an end face of an end portion of the cathode portion exposed from the exterior body at least on the second main surface and electrically connected to the second external electrode, the anode body has a first recess recessed in a direction from the second main surface toward the fourth main surface, an electrolytic capacitor in which an end portion of the cathode portion extends from the first recess of the anode body so as to protrude toward the second main surface.

2. In the first capacitor element, an end face of the cathode portion exposed from the exterior body on the second main surface is located closer to the first main surface than the third main surface. The electrolytic capacitor according to claim 1.

3. The end portions of the anode body include a pair of first end portions facing each other in a first direction, the end portions of the cathode portion include a pair of second end portions facing each other in a second direction intersecting with the first direction, in the first capacitor element, a first end face A which is one end face of the pair of first end portions is exposed from the exterior body on the first main surface and electrically connected to the first external electrode, and a second end face A which is one end face of the pair of second end portions is exposed from the exterior body on the second main surface and electrically connected to the second external electrode. The electrolytic capacitor according to claim 1 or 2.

4. A third end face A which is the other end face of the pair of first end portions of the first capacitor element is exposed from the exterior body on the third main surface and electrically connected to a third external electrode. The electrolytic capacitor according to claim 3.

5. The plurality of capacitor elements further includes at least one second capacitor element, The third end face A, which is the other end face of the pair of first end parts of the first capacitor element, is not exposed from the exterior body on the third main face. In the second capacitor element, the first end face B, which is one end face of the pair of first end parts, is not exposed from the exterior body on the first main face, and the third end face B, which is the other end face of the pair of first end parts, is exposed from the exterior body on the third main face. In the element laminate, the first capacitor element and the second capacitor element are alternately laminated. The electrolytic capacitor according to claim 3, wherein the third end face B of the second capacitor element is electrically connected to a third external electrode.

6. The electrolytic capacitor according to any one of claims 3 to 5, wherein the fourth end face A, which is the other end face of the pair of second end parts of the first capacitor element, is exposed from the exterior body on the fourth main face and is electrically connected to a fourth external electrode.

7. The plurality of capacitor elements further includes at least one third capacitor element. The fourth end face A, which is the other end face of the pair of second end parts of the first capacitor element, is not exposed from the exterior body on the fourth main face. In the third capacitor element, the second end face C, which is one end face of the pair of second end parts, is not exposed from the exterior body on the second main face, and the fourth end face C, which is the other end face of the pair of second end parts, is exposed from the exterior body on the fourth main face. In the element laminate, the first capacitor element and the third capacitor element are alternately laminated. The electrolytic capacitor according to claim 3 or 4, wherein the fourth end face C of the third capacitor element is electrically connected to a fourth external electrode.

8. The anode body has a pair of recesses recessed in the second direction. The electrolytic capacitor according to any one of claims 3 to 7, wherein the pair of recesses includes the first recess and a second recess recessed in a direction from the fourth main face toward the second main face.

9. The electrolytic capacitor according to claim 8, wherein each of the pair of second end parts extends so as to protrude from the pair of recesses of the anode body.

10. The first capacitor element has a second end face A, which is an end face on the second main surface of the end portion of the cathode portion, exposed from the exterior body and electrically connected to the second external electrode, and a fourth end face A, which is an end face on the fourth main surface of the end portion of the cathode portion, exposed from the exterior body and electrically connected to the second external electrode. The electrolytic capacitor according to any one of claims 1 to 3.

11. An end portion of the anode body is not exposed from the third main surface of the exterior body, and a third end face A, which is an end face on the third main surface of the end portion of the cathode portion, is exposed from the exterior body and the third end face A is electrically connected to a third external electrode. The electrolytic capacitor according to any one of claims 1 to 3 and 10.

12. Neither the end portion of the anode body nor the end portion of the cathode portion is exposed from the third main surface of the exterior body. The electrolytic capacitor according to any one of claims 1 to 3 and 10.

13. A third external electrode is arranged so as to cover a side of the third main surface rather than the second external electrode on the bottom surface of the electrolytic capacitor. The electrolytic capacitor according to claim 12.

14. The cathode portion has a solid electrolyte layer covering at least a part of the dielectric layer. In at least one of the plurality of capacitor elements, the cathode portion further has a cathode foil covering at least a part of the solid electrolyte layer. A part of the cathode foil covers the solid electrolyte layer, and the remaining portion of the cathode foil that does not cover the solid electrolyte layer constitutes the end portion of the cathode portion. The electrolytic capacitor according to any one of claims 1 to 13.

15. The cathode foil is a sintered foil, a vapor-deposited foil, or a coated foil. The electrolytic capacitor according to claim 14.

16. The sintered foil, the vapor-deposited foil, or the coated foil has a surface of a metal foil covered with a conductive film. The electrolytic capacitor according to claim 15.

17. The conductive film is at least one selected from the group consisting of Ti, TiC, TiO, and C (carbon) films. The electrolytic capacitor according to claim 16.

18. A separation distance between the first main surface and the third main surface is shorter than a separation distance between the second main surface and the fourth main surface. The electrolytic capacitor according to any one of claims 1 to 17.

19. The electrolytic capacitor according to any one of claims 1 to 17, wherein the separation distance between the first main surface and the third main surface is longer than the separation distance between the second main surface and the fourth main surface.

20. The electrolytic capacitor according to any one of claims 1 to 19, wherein at least one of the first external electrode and the second external electrode includes a plurality of electrode portions arranged apart along the first main surface or the second main surface.

21. A method for manufacturing an electrolytic capacitor including an element laminate including a plurality of capacitor elements each having an anode body having a porous portion on a surface, a dielectric layer formed on at least a part of the surface of the porous portion, and a cathode portion covering at least a part of the dielectric layer, a step of obtaining an element assembly in which the plurality of element laminates are arranged on a plane perpendicular to the stacking direction, a step of individualizing the element assembly into the plurality of element laminates, and a step of electrically connecting an end portion of the anode body of the element laminate to a first external electrode and an end portion of the cathode portion of the element laminate to a second external electrode. The step of obtaining the element assembly includes (i)a step of preparing an anode foil having the porous portion formed on a surface, (ii)a step of forming the dielectric layer on the surface of the anode foil, (iii)a step of forming a first opening in the anode foil, (iv)a step of forming a solid electrolyte layer in a first region of the anode foil, (v)a step of preparing a cathode foil processed into a shape having a second region partially facing the first region, (vi)a step of alternately stacking the anode foil and the cathode foil, wherein the arrangement pattern of the first region of the anode foil and the second region of the cathode foil has a periodic pattern in which a unit pattern is periodically repeated in at least one of a first direction and a second direction intersecting the first direction. The unit pattern in the first region is a region A located at the center in the first direction １ , the region A １ extends from the region A in the first direction ２ , and includes a region A extending in the first direction from the region A1 to the side opposite to the region A2 The unit pattern in the second region is the region A corresponding to the region A of the anode foil １ in the anode foil ３ , and the region A ３ extending from the region A in the second direction ４ and includes The unit pattern of the first region has a shape along an edge of the first opening and has a recess recessed in the second direction. A method for manufacturing an electrolytic capacitor.

22. The method for manufacturing an electrolytic capacitor according to claim 21, further including a step of forming an insulating layer on an end surface of the anode foil exposed in the first opening after the step (iii) and before the step (iv).

23. The unit pattern in the second region is the region A ３ extending from the region A in the first direction ５ and includes Said region A ５ wherein at least a part thereof overlaps with said region A of said anode foil ２ The method for manufacturing an electrolytic capacitor according to claim 21 or 22.

24. The step of obtaining the element assembly includes a step of forming a second opening extending in the second direction in a first pattern to obtain a first anode foil. forming the second opening with a second pattern different from the first pattern to obtain a second anode foil; and The second opening is located outside the first pattern and outside the first region, and is in a region on the side opposite to the region A with the region A interposed therebetween, or is formed in a region outside the first region and on the side opposite to the region A with the region A interposed therebetween. ２ with the region A interposed therebetween １ and in a region on the side opposite to the region A ７ with the region A interposed therebetween １ and in a region on the side opposite to the region A. The second opening is an area in the second pattern corresponding to the area in the first pattern where the second opening is not formed, outside the first area, and is the area A ２ with the area A １ on the opposite side across it, or is an area in the first pattern corresponding to the area where the second opening is not formed, outside the first area, and is the area A ７ with the area A １ formed on the opposite side across it, The method for manufacturing an electrolytic capacitor according to any one of claims 21 to 23, wherein in the step (vi), the first anode foil, the cathode foil, the second anode foil, and the cathode foil are laminated in this order.

25. the said region A ４ is the said region A ３ a step of obtaining a first cathode foil extending from the said region A in one direction of the said second direction; the said region A ４ is the said region A ３ and a step of obtaining a second cathode foil extending from the said region A in the other direction of the second direction, and further has The method for manufacturing an electrolytic capacitor according to any one of claims 21 to 24, wherein in the step (vi), the anode foil, the first cathode foil, the anode foil, and the second cathode foil are laminated in this order.

26. The first cathode foil does not have the region A ３ extending in the other direction of the second direction from the region A ６ or the extension distance of the region A ６ in the other direction of the second direction from the region A ３ is shorter than the extension distance of the region A ４ in the one direction of the second direction from the region A ３ ​ The second cathode foil does not have the region A ３ extending in one direction of the second direction from the region A ６ or the extension distance of the region A ６ in the region A ３ in one direction of the second direction from the region A is shorter than the extension distance of the region A ４ in the region A ３ in the other direction of the second direction from the region A. The method for manufacturing an electrolytic capacitor according to claim 25

27. The second region is the region A ３ extending from the region A ４ in a direction opposite to the extending direction of the region A ６ The manufacturing method of the electrolytic capacitor according to any one of claims 21 to 26, including

28. The step of individualizing the element assembly is (vii) a step of filling, with an exterior body, the first opening of the anode foil of the element assembly and regions other than the second region of the cathode foil; (viii) a step of cutting the element assembly with a cut line that does not cross the first region and is parallel to the second direction, to expose an end face of the anode foil on a first main surface of the exterior body; (ix) cutting the element assembly along a cutting line parallel to the first direction crossing the region A ４ and exposing an end face of the cathode foil on the second main surface of the exterior body, the method for manufacturing an electrolytic capacitor according to any one of claims 21 to 27, comprising the step.

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