Solid electrolytic capacitor

Abstract

This solid electrolytic capacitor comprises: a sheet laminate formed by laminating a first capacitor element and a second capacitor element each having a dielectric layer formed on a surface of each flat electrode foil, and a solid electrolyte layer formed on the surface of the dielectric layer; and an insulating resin that seals the sheet laminate. A first pole is formed by pulling out the electrode foil of the first capacitor element from a first end of the sheet laminate, and a second pole is formed by pulling out the electrode foil of the second capacitor element from a second end facing the first end of the sheet laminate.

Description

solid electrolytic capacitor

[0001] The present invention relates to a solid electrolytic capacitor having a laminate in which a plurality of capacitor elements are stacked.

[0002] Patent Document 1 describes a method for manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor. The solid electrolytic capacitor described in Patent Document 1 includes a plurality of flat-film capacitor elements and a plurality of metal foils (cathodes). The flat-film capacitor elements include a foil-shaped valve metal substrate (anode), a porous portion of the valve metal substrate and a dielectric layer formed on the surface thereof, and a solid electrolyte layer formed on the surface of the dielectric layer.

[0003] More specifically, the capacitor element of Patent Document 1 has the following configuration: The porous portion of the capacitor element is impregnated with an insulating resin (mask member). Furthermore, an insulating adhesive is formed in a frame shape in the insulating resin. A solid electrolyte layer is formed within the frame of the insulating adhesive. Flat film-shaped capacitor elements and metal foils are alternately stacked. This forms an element stack.

[0004] Japanese Patent Application Laid-Open No. 2019-79866

[0005] However, when using a solid electrolytic capacitor such as that disclosed in Patent Document 1, the capacitor elements are connected in parallel. That is, in order to increase the withstand voltage of the solid electrolytic capacitor, it is necessary to increase the number of stacked capacitor elements. That is, the size of the solid electrolytic capacitor increases.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a solid electrolytic capacitor that has high breakdown voltage, is compact, and is easy to manufacture.

[0007] The solid electrolytic capacitor of the present invention includes a sheet laminate formed by stacking first and second capacitor elements, each having a flat electrode foil on which a dielectric layer is formed and a solid electrolyte layer on which a dielectric layer is formed, and an insulating resin that seals the sheet laminate. The electrode foil of the first capacitor element is pulled out from a first end face of the sheet laminate to form a first pole, and the electrode foil of the second capacitor element is pulled out from a second end face opposite the first end face of the sheet laminate to form a second pole.

[0008] This configuration makes it possible to easily form a non-polar solid electrolytic capacitor, and because the capacitor elements are connected in series, a high breakdown voltage can be achieved.

[0009] According to the present invention, it is possible to provide a solid electrolytic capacitor that has a high breakdown voltage, is compact, and is easy to manufacture.

[0010] FIG. 1 is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to a first embodiment. FIG. 2(A) is a side cross-sectional view showing the configuration of a capacitor element before singulation, and FIG. 2(B) is a side cross-sectional view showing an outline of a structure in which capacitor elements are stacked. FIG. 3 is a circuit diagram of the solid electrolytic capacitor according to the first embodiment. FIG. 4 is a flowchart showing an example of a general flow of a method for manufacturing the solid electrolytic capacitor according to the first embodiment. FIG. 5 is a flowchart showing an example of a process for forming a capacitor element sheet. FIG. 6(A) is an external perspective view showing the shape of a capacitor element before singulation, and FIG. 6(B) is an external perspective view showing the shape of a capacitor element before singulation. FIG. 7 is an external view of a multi-layer capacitor element. FIG. 8 is a flowchart showing an example of a process for forming a sheet laminate. FIG. 9 is an exploded perspective view of a sheet laminate. FIG. 10 is an exploded perspective view of a set of capacitor elements stacked. FIG. 11 is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to a second embodiment. FIG. 12 is a side cross-sectional view showing an outline of a structure in which capacitor elements according to the second embodiment are stacked. Fig. 13(A) is an external perspective view showing the shape of the third capacitor element before singulation, and Fig. 13(B) is an external perspective view showing the shape of the third capacitor element before singulation. Fig. 14 is a circuit diagram of the solid electrolytic capacitor according to the second embodiment. Fig. 15 is a side cross-sectional view showing the configuration of the solid electrolytic capacitor according to the third embodiment. Fig. 16 is a side cross-sectional view showing an outline of the structure in which capacitor elements according to the third embodiment are stacked. Fig. 17 is a side cross-sectional view showing an outline of the structure in which capacitor elements according to the fourth embodiment are stacked.

[0011] First Embodiment A solid electrolytic capacitor according to a first embodiment of the present invention and a method for manufacturing the solid electrolytic capacitor will be described with reference to the drawings.

[0012] (Explanation of Schematic Configuration of Solid Electrolytic Capacitor 1) First, the structure of a solid electrolytic capacitor according to an embodiment of the present invention will be described. FIG. 1 is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to a first embodiment. Note that in FIG. 1, only the insulating resin and external electrodes are hatched to make the drawing easier to see. FIG. 2(A) is a side cross-sectional view showing the configuration of a capacitor element before singulation, and FIG. 2(B) is a side cross-sectional view showing an overview of the structure in which capacitor elements are stacked.

[0013] As shown in Figures 1, 2(A), and 2(B), the solid electrolytic capacitor 1 includes a capacitor element laminate 100, an insulating resin 50, an external electrode 61, and an external electrode 62. The capacitor element laminate 100 includes a plurality of flat-film-shaped first capacitor elements 10A and a plurality of second capacitor elements 10B. Note that in Figure 1, the number (number) of flat-film-shaped first capacitor elements 10A and second capacitor elements 10B is two each, but this is not limited to this. Note that the external electrode 61 corresponds to the "first external electrode" in the present invention, and the external electrode 62 corresponds to the "second external electrode" in the present invention.

[0014] 2A, first capacitor element 10A and second capacitor element 10B include flat film-like electrode 11, dielectric layer 12, and CP layer (solid electrolyte layer) 13. Electrode 11 corresponds to the "electrode foil" of the present invention.

[0015] Although detailed structural illustrations are omitted in Figures 2(A) and 2(B), the electrode 11 has a large number of pores. In other words, the electrode 11 is porous (a porous body). The thickness ratio of the porous portion on one side of the electrode 11 to the core metal portion and the porous portion on the other side is approximately 1:1:1. The dielectric layer 12 covers the outer surface of the electrode 11. Because detailed structural illustrations of the electrode 11 are omitted in Figures 2(A) and 2(B), the dielectric layer 12 is illustrated as if it were covering the macroscopic surface of the electrode 11. In reality, the dielectric layer 12 covers not only the macroscopic surface of the electrode 11 but also the surfaces of the numerous pores in the electrode 11.

[0016] The CP layer 13 covers the surface of the dielectric layer 12. The CP layer 13 is formed inside a frame-shaped first dam 14. The first dam 14 is insulating. The first dam 14 limits the formation area of ​​the CP layer 13. In the first embodiment, as described in the manufacturing method described below, the first dam 14 is formed in a frame shape, and then the CP layer 13 is formed inside the first dam 14. However, depending on the manufacturing method of the capacitor element 10, for example, when the capacitor element 10 is produced in an individualized state from the beginning, the first dam 14 does not have to be formed in a frame shape. That is, the first dam 14 may be formed on one side, or on two sides having a corner. Furthermore, the first dam 14 may be formed on two opposing sides in a planar view. In addition, if the CP layer can be formed only on the surface of the dielectric layer 12, the first dam 14 may be omitted.

[0017] The CP layer 13 has a laminated structure of an inner layer CP (inner layer solid electrolyte layer) 131 and an outer layer CP (outer layer solid electrolyte layer) 132. The inner layer CP 131 is formed on the surface of the dielectric layer 12, and the outer layer CP 132 is formed on the surface of the inner layer CP 131.

[0018] The plurality of first capacitor elements 10A and the plurality of second capacitor elements 10B are alternately stacked so that their flat film surfaces are parallel to each other and so that they overlap in plan view.

[0019] Between the first capacitor element 10A and the second capacitor element 10B, an outer layer CP (outer solid electrolyte layer) 132 is disposed. The first capacitor element 10A and the second capacitor element 10B are bonded to each other using the outer layer CP 132.

[0020] Furthermore, a carbon layer may be formed between the first capacitor element 10A and the second capacitor element 10B so as to abut against the outer layer CP132. By forming the carbon layer, the adhesive strength between the first capacitor element 10A and the second capacitor element 10B can be improved, and low resistance can be achieved. When a carbon layer is formed, it is preferable that a second dam (not shown) be present to restrict the formation area of ​​the carbon layer.

[0021] Although the example has been shown in which the first capacitor element 10A and the second capacitor element 10B each have the outer layer CP132, it is also possible to omit one of the outer layers CP132 at the contact surface between the first capacitor element 10A and the second capacitor element 10B. In this case, the thickness of the solid electrolytic capacitor 1 can be reduced by the amount of the omitted outer layer CP132.

[0022] In this stacked state, the first ends EA1 of the multiple first capacitor elements 10A are located at approximately the same position in side view. Similarly, the second ends EA2 of the multiple first capacitor elements 10A are located at approximately the same position in side view. Furthermore, the first ends EB1 of the multiple second capacitor elements 10B are located at approximately the same position in side view. Similarly, the second ends EB2 of the multiple second capacitor elements 10B are located at approximately the same position in side view.

[0023] The first ends EA1 of the multiple first capacitor elements 10A and the second ends EB2 of the multiple second capacitor elements 10B are arranged on the first end side of the capacitor element stack 100. The first ends EA1 of the multiple first capacitor elements 10A protrude outward more than the second ends EB2 of the multiple second capacitor elements 10B. The first ends EA1 of the first capacitor elements 10A correspond to the "first pole" of the present invention. This first end EA1 is part of the first end surface of the capacitor element stack 100.

[0024] The first ends EB1 of the plurality of second capacitor elements 10B and the second ends EA2 of the plurality of first capacitor elements 10A are arranged on the second end side of the capacitor element stack 100. The first ends EB1 of the plurality of second capacitor elements 10B protrude outward beyond the second ends EA2 of the plurality of first capacitor elements 10A. The first ends EB1 of the second capacitor elements 10B correspond to the "second pole" of the present invention. This first end EB1 is part of the second end surface of the capacitor element stack 100.

[0025] With this structure, the capacitor element laminate 100 is realized.

[0026] The capacitor element stack 100 is sealed with insulating resin 50. More specifically, the insulating resin 50 covers the capacitor element stack 100 except for first ends EA1 of the plurality of first capacitor elements 10A and first ends EB1 of the plurality of second capacitor elements 10B.

[0027] The external electrode 61 covers the first end (the first end EA1 of the first capacitor element 10A) of the insulating resin 50. The external electrode 61 is connected to the first ends EA1 of the electrodes 11 of the plurality of first capacitor elements 10A.

[0028] The external electrode 62 covers the second end (the first end EB1 of the second capacitor element 10B) of the insulating resin 50. The external electrode 62 is connected to the first ends EB1 of the electrodes 11 of the plurality of second capacitor elements 10B.

[0029] The above configuration realizes the non-polar (bipolar) solid electrolytic capacitor 1 of the first embodiment. In other words, the solid electrolytic capacitor 1 has a symmetrical shape in which the structure from the external electrode 61 to the external electrode 62 is the same as the structure from the external electrode 62 to the external electrode 61. Note that although the first capacitor element 10A and the second capacitor element 10B have been described using different symbols, in the first embodiment, the first capacitor element 10A and the second capacitor element 10B have the same configuration. However, the first capacitor element 10A and the second capacitor element 10B may have different configurations.

[0030] Here, a comparison is made between a case where the first capacitor element 10A and the second capacitor element 10B have the same configuration and a case where they have different configurations. When the first capacitor element 10A and the second capacitor element 10B have the same configuration, the capacitance efficiency is good and it is possible to design the voltage balance for the solid electrolytic capacitor 1 to be even.

[0031] (Circuit Configuration of Solid Electrolytic Capacitor 1) Next, the circuit configuration of the solid electrolytic capacitor 1 will be described with reference to Fig. 3. Fig. 3 shows a circuit including a pair of a first capacitor element 10A and a second capacitor element 10B. As shown in the equivalent circuit diagram of the solid electrolytic capacitor 1, the first capacitor element 10A, the second capacitor element 10B, the first capacitor element 10A, and the second capacitor element 10B are connected in series.

[0032] That is, the withstand voltage across solid electrolytic capacitor 1 is the sum of the withstand voltage of first capacitor element 10A, the withstand voltage of second capacitor element 10B, the withstand voltage of first capacitor element 10A, and the withstand voltage of second capacitor element 10B.

[0033] Therefore, compared to conventional solid electrolytic capacitors formed by stacking cathode electrodes and anode electrodes, the present invention can easily realize a solid electrolytic capacitor with a high breakdown voltage. In particular, when there are two or more pairs of first capacitor element 10A and second capacitor element 10B, there are capacitors connected in parallel, so a high breakdown voltage can be more reliably realized.

[0034] (Method of Manufacturing Solid Electrolytic Capacitor 1) The solid electrolytic capacitor 1 having the above-described configuration is manufactured, for example, as follows: Fig. 4 is a flowchart showing an example of a schematic flow of the method of manufacturing the solid electrolytic capacitor according to the first embodiment.

[0035] A capacitor element sheet is formed (FIG. 4: S11). The first capacitor element sheet is formed with an array of first capacitor elements 10A, each of which forms a different solid electrolytic capacitor 1. Similarly, the second capacitor element sheet is formed with an array of second capacitor elements 10B, each of which forms a different solid electrolytic capacitor 1.

[0036] Next, the first capacitor element sheet and the second capacitor element sheet are stacked to form a sheet laminate ( FIG. 4 : S12). This forms a structure in which a plurality of capacitor element laminates 100 are arranged in a plane. In other words, the sheet laminate is a structure in which a plurality of capacitor element laminates 100 are arranged in a plane.

[0037] Next, the sheet stack is sealed with insulating resin 50 (FIG. 4: S13). As will be described in detail later, at this time, through holes that penetrate from the top surface to the bottom surface of the sheet stack are provided in the sheet stack, and resin sealing is performed by compression molding.

[0038] The process up to this sealing with insulating resin 50 is carried out in a multi-state (state in which a plurality of what will become solid electrolytic capacitors 1 are arranged) before the solid electrolytic capacitor 1 is divided into individual pieces.

[0039] Next, the sheet laminate sealed with insulating resin 50 is cut and separated into individual pieces ( FIG. 4 : S14). Specifically, cutting is performed along cutting lines formed at arbitrary positions. This results in multiple solid electrolytic capacitors 1 (referred to as "solid electrolytic capacitor 1 element bodies") without external electrodes. After this, the solid electrolytic capacitor 1 element bodies are secondary sealed with insulating resin 50. More specifically, the side surfaces of the solid electrolytic capacitor 1 element bodies (surfaces cut along cutting lines formed at arbitrary positions (top surface, bottom surface, and side surfaces other than the end surfaces where the electrodes 11 of the first capacitor element 10A and the electrodes 11 of the second capacitor element 10B are exposed)) are covered with the secondary sealing of insulating resin 50. This allows the electrodes 11 of the first capacitor element 10A and the electrodes 11 of the second capacitor element 10B, which are unnecessarily exposed during singulation, to be covered with insulating resin 50.

[0040] Next, external electrodes 61 and 62 are formed on the end surfaces of the element body of solid electrolytic capacitor 1 (FIG. 4: S15).

[0041] Next, each step will be described in more detail.

[0042] (Capacitor element sheet forming process) FIG. 5 is a flowchart showing an example of a capacitor element sheet forming process. FIG. 6(A) is an external perspective view showing the shape of the electrodes of the capacitor element before singulation, and FIG. 6(B) is an external perspective view showing the shape of the capacitor element before singulation. FIG. 7 is an external view of the capacitor element in a multi-layer state. In the following forming process, the forming process of the first capacitor element 10A and the second capacitor element 10B is the same. Here, the first capacitor element 10A will be described as an example.

[0043] The electrode 11 of the first capacitor element 10A is subjected to a chemical conversion treatment to form the dielectric layer 12 (FIG. 5: S111). At this time, a large number of holes are formed on the surface of the electrode 11 by etching, and the vicinity of the surface of the electrode 11 is made porous. The dielectric layer 12 covers the surface of the electrode 11, including the inner surfaces of the holes.

[0044] Next, through holes are formed in the electrode 11 ( FIG. 5 : S112). More specifically, as shown in FIG. 6A , a plurality of cylindrical through holes 19C and groove-shaped through holes 19L are formed in the electrode 11. The cylindrical through holes 19C and the groove-shaped through holes 19L are alternately arranged along the direction in which the portions that will become the electrodes 11 are arranged. The cylindrical through holes 19C are formed at positions that will form first ends EA1 of the electrodes 11, and the groove-shaped through holes 19L are formed at positions that straddle the portions that will become adjacent electrodes 11 and at positions that will form second ends EA2 of the adjacent electrodes 11.

[0045] Next, a CP layer (solid electrolyte layer) 13 is formed on the surface of the dielectric layer 12 (FIG. 5: S113). More specifically, as shown in FIG. 6B, a first dam 14 having a frame-shaped opening is formed. Then, the CP layer 13 (a laminated structure of an inner layer CP 131 and an outer layer CP 132) is formed within the opening of the first dam 14.

[0046] 7, this structure is implemented in a multi-state in which a plurality of capacitor elements 10 (structures consisting of electrodes 11, dielectric layers 12, CP layers 13, and first dams 14) are arranged two-dimensionally. As described above, cutting is performed along the cutting lines to form the solid electrolytic capacitors 1. This results in a plurality of solid electrolytic capacitors 1 (referred to as solid electrolytic capacitor 1 bodies) without external electrodes formed thereon.

[0047] (Sheet Laminate Forming Process) Fig. 8 is a flowchart showing an example of a sheet laminate forming process. Fig. 9 is an exploded perspective view showing a state in which a first capacitor element sheet and a second capacitor element sheet are laminated. Fig. 10 is an exploded perspective view showing a state in which a set of a first capacitor element 10A and a second capacitor element 10B are laminated.

[0048] As shown in Fig. 9, the first capacitor element sheets and the second capacitor element sheets are alternately stacked (Fig. 8: S121). At this time, the first capacitor element sheets and the second capacitor element sheets are stacked so that their orientations are staggered. This makes it possible to realize a structure in which the first end E1 of the first capacitor element 10A and the second end E2 of the second capacitor element 10B protrude, as shown in Fig. 1, for example.

[0049] 9 and 10 , the first capacitor element 10A and the second capacitor element 10B are alternately stacked. In this case, the through hole 19C of the first capacitor element 10A overlaps with the through hole 19L of the second capacitor element 10B when viewed in the stacking direction (the Z-axis direction in FIG. 10 ). Similarly, the through hole 19L of the first capacitor element 10A overlaps with the through hole 19C of the second capacitor element 10B when viewed in the stacking direction (the Z-axis direction in FIG. 10 ).

[0050] Similarly, when multiple first capacitor elements 10A and second capacitor elements 10B are stacked, the through hole 19C of the first capacitor element 10A overlaps with the through hole 19L of the second capacitor element 10B when viewed in the stacking direction (the Z-axis direction in Figure 10), and the through hole 19L of the first capacitor element 10A is stacked so as to overlap with the through hole 19C of the second capacitor element 10B.

[0051] The number of these through holes formed corresponds to the number of capacitor elements arranged in the sheet laminate, and therefore the sheet laminate is provided with a plurality of through holes that penetrate from the top surface to the bottom surface of the sheet laminate.

[0052] Next, the sheet laminate is heated and pressurized ( FIG. 8 : S122). This bonds the first capacitor element sheet and the second capacitor element sheet together to form a sheet laminate. Note that the first capacitor element sheet and the second capacitor element sheet are bonded together by the outer layer CP132 as described above.

[0053] [Second Embodiment] Next, a solid electrolytic capacitor according to a second embodiment will be described with reference to the drawings. Fig. 11 is a side cross-sectional view showing the configuration of the solid electrolytic capacitor according to the second embodiment. Fig. 12 is a side cross-sectional view showing an outline of a structure in which capacitor elements according to the second embodiment are stacked. Fig. 13(A) is an external perspective view showing the shape of the electrodes of a third capacitor element before singulation, and Fig. 13(B) is an external perspective view showing the shape of the third capacitor element before singulation.

[0054] As shown in Fig. 11 , the solid electrolytic capacitor 1A according to the second embodiment differs from the solid electrolytic capacitor 1 according to the first embodiment in that it includes a third capacitor element 10C. The other configuration of the solid electrolytic capacitor 1A is the same as that of the solid electrolytic capacitor 1, and a description of similar parts will be omitted. Note that in Fig. 11 , the number (number) of flat-film-shaped first capacitor element 10A, second capacitor element 10B, and third capacitor element 10C is one each, but this is not limited to one.

[0055] The capacitor element laminate 100A includes a flat film-shaped first capacitor element 10A, a second capacitor element 10B, and a third capacitor element 10C. As in the first embodiment, the external electrode 61 corresponds to the "first electrode" (positive electrode) of the present invention, and the external electrode 62 corresponds to the "second electrode" (negative electrode) of the present invention.

[0056] 11 and 12 , the first capacitor element 10A and the second capacitor element 10B include a flat film-shaped electrode 11, a dielectric layer 12, and a CP layer (solid electrolyte layer) 13. The third capacitor element 10C includes a flat film-shaped electrode 11C, a dielectric layer 12, and a CP layer (solid electrolyte layer) 13. The dielectric layer 12 and the CP layer 13 have the same configurations as those of the first capacitor element 10A and the second capacitor element 10B.

[0057] The first capacitor element 10A and the third capacitor element 10C are stacked so that their flat film surfaces are parallel and overlap in a planar view. Similarly, the third capacitor element 10C and the second capacitor element 10B are stacked so that their flat film surfaces are parallel and overlap in a planar view. That is, the first capacitor element 10A, the third capacitor element 10C, and the second capacitor element 10B are stacked alternately so that their flat film surfaces are parallel and overlap in a planar view.

[0058] An outer layer CP132 exists between the first capacitor element 10A and the third capacitor element 10C. The first capacitor element 10A and the third capacitor element 10C are bonded together using this outer layer CP132. Similarly, an outer layer CP132 exists between the third capacitor element 10C and the second capacitor element 10B. The third capacitor element 10C and the second capacitor element 10B are bonded together using this outer layer CP132.

[0059] As in the first embodiment, it is possible to omit either the outer layer CP132 at the contact surface between the first capacitor element 10A and the third capacitor element 10C or the contact surface between the third capacitor element 10C and the second capacitor element 10B. In this case, the thickness of the solid electrolytic capacitor 1A can be reduced by the amount of the omitted outer layer CP132.

[0060] The first end EA1 of the first capacitor element 10A, the second end EB2 of the second capacitor element 10B, and the first end EC1 of the third capacitor are arranged on the first end side of the capacitor element stack 100. The first end EA1 of the first capacitor element 10A protrudes outward further than the second end EB2 of the second capacitor element 10B and the first end EC1 of the third capacitor.

[0061] The first end EB1 of the second capacitor element 10B, the second end EA2 of the first capacitor element 10A, and the second end EC2 of the third capacitor are arranged on the second end side of the capacitor element stack 100. The first end EB1 of the second capacitor element 10B and the second end EC2 of the third capacitor protrude outward beyond the second end EA2 of the first capacitor element 10A.

[0062] That is, the first end EC1 of the third capacitor element 10C is not connected to the external electrode 61, and the second end EC2 is not connected to the external electrode 62.

[0063] Here, the shape of the third capacitor element 10C will be described in detail using Figures 13(A) and 13(B). As shown in Figure 13(A), a through hole is formed in the electrode 11C. More specifically, groove-shaped through holes 19L are formed at both ends of the electrode 11C. The groove-shaped through holes 19L are formed at positions that realize the first end EC1 and the second end EC2 of the third capacitor element 10C.

[0064] With this structure, the capacitor element laminate 100A is realized.

[0065] The capacitor element laminate 100A is sealed with insulating resin 50. More specifically, the insulating resin 50 covers the capacitor element laminate 100A except for the first end EA1 of the first capacitor element 10A and the first end EB1 of the second capacitor element 10B.

[0066] The external electrode 61 covers the first end (the first end EA1 of the first capacitor element 10A) of the insulating resin 50. The external electrode 61 is connected to the first ends EA1 of the electrodes 11 of the plurality of first capacitor elements 10A.

[0067] The external electrode 62 covers the second end (the first end EB1 of the second capacitor element 10B) of the insulating resin 50. The external electrode 62 is connected to the first ends EB1 of the electrodes 11 of the plurality of second capacitor elements 10B.

[0068] As shown in the equivalent circuit diagram of solid electrolytic capacitor 1A (FIG. 14), first capacitor element 10A, third capacitor element 10C, and second capacitor element 10B are connected in series.

[0069] That is, the withstand voltage across solid electrolytic capacitor 1A is the sum of the withstand voltage of first capacitor element 10A, the withstand voltage of second capacitor element 10B, and the withstand voltage of third capacitor element 10C.

[0070] Even with this configuration, the present invention can realize a solid electrolytic capacitor with a higher breakdown voltage than a conventional solid electrolytic capacitor formed by stacking cathode electrodes and anode electrodes.

[0071] [Third Embodiment] Next, a solid electrolytic capacitor according to a third embodiment will be described with reference to the drawings. Fig. 15 is a side cross-sectional view showing the configuration of the solid electrolytic capacitor according to the third embodiment. Fig. 16 is a side cross-sectional view showing an outline of the structure in which capacitor elements according to the third embodiment are stacked.

[0072] 15 and 16 , the solid electrolytic capacitor 1B according to the third embodiment differs from the solid electrolytic capacitor 1A according to the second embodiment in that it includes a plurality of third capacitor elements 10C. The other configuration of the solid electrolytic capacitor 1B is the same as that of the solid electrolytic capacitor 1A, and a description of similar parts will be omitted.

[0073] The capacitor element laminate 100A includes a plurality of flat film-shaped first capacitor elements 10A, second capacitor elements 10B, and a plurality of third capacitor elements 10C. As in the first embodiment, the external electrode 61 corresponds to the "first external electrode" (positive electrode) of the present invention, and the external electrode 62 corresponds to the "second external electrode" (negative electrode) of the present invention.

[0074] The first capacitor element 10A and the third capacitor element 10C are stacked so that their flat film surfaces are parallel and overlap in a planar view. The third capacitor element 10C and the third capacitor element 10C are stacked so that their flat film surfaces are parallel and overlap in a planar view. The third capacitor element 10C and the second capacitor element 10B are stacked so that their flat film surfaces are parallel and overlap in a planar view. That is, the first capacitor element 10A and the plurality of third capacitor elements 10C and the second capacitor element 10B are stacked alternately so that their flat film surfaces are parallel and overlap in a planar view.

[0075] An outer layer CP132 is present between the first capacitor element 10A and the third capacitor element 10C. The first capacitor element 10A and the third capacitor element 10C are bonded to each other using this outer layer CP132.

[0076] Furthermore, an outer layer CP132 is present between the third capacitor elements 10C and 10C. The outer layer CP132 is used to bond the third capacitor elements 10C and 10C together.

[0077] Similarly, an outer layer CP132 is present between the third capacitor element 10C and the second capacitor element 10B. The third capacitor element 10C and the second capacitor element 10B are bonded together using this outer layer CP132.

[0078] As in the second embodiment, it is possible to omit one of the outer layers CP132 from the surface where the first capacitor element 10A and the third capacitor element 10C abut, the surface where the third capacitor element 10C and the third capacitor element 10C abut, or the surface where the third capacitor element 10C and the second capacitor element 10B abut. In this case, the thickness of the solid electrolytic capacitor 1B can be reduced by the amount of the omitted outer layer CP132.

[0079] The first end EA1 of the first capacitor element 10A, the second end EB2 of the second capacitor element 10B, and the first end EC1 of the third capacitor are arranged on the first end side of the capacitor element stack 100. The first end EA1 of the first capacitor element 10A protrudes outward further than the second end EB2 of the second capacitor element 10B and the first end EC1 of the third capacitor.

[0080] The first end EB1 of the second capacitor element 10B, the second end EA2 of the first capacitor element 10A, and the second end EC2 of the third capacitor are arranged on the second end side of the capacitor element stack 100. The first end EB1 of the second capacitor element 10B and the second end EC2 of the third capacitor protrude outward beyond the second end EA2 of the first capacitor element 10A.

[0081] With this structure, the capacitor element laminate 100B is realized.

[0082] The capacitor element laminate 100B is sealed with insulating resin 50. More specifically, the insulating resin 50 covers the capacitor element laminate 100B except for the first end EA1 of the first capacitor element 10A and the first end EB1 of the second capacitor element 10B.

[0083] The external electrode 61 covers the first end of the insulating resin 50. The external electrode 61 is connected to the first ends EA1 of the electrodes 11 of the plurality of first capacitor elements 10A.

[0084] The external electrode 62 covers the second end of the insulating resin 50. The external electrode 62 is connected to the first ends EB1 of the electrodes 11 of the plurality of second capacitor elements 10B.

[0085] That is, the withstand voltage across solid electrolytic capacitor 1B is the sum of the withstand voltage of first capacitor element 10A, the withstand voltage of second capacitor element 10B, and the withstand voltage of the plurality of third capacitor elements 10C.

[0086] Even with this configuration, the present invention can realize a solid electrolytic capacitor with a higher breakdown voltage than a conventional solid electrolytic capacitor formed by stacking cathode electrodes and anode electrodes.

[0087] Fourth Embodiment A solid electrolytic capacitor according to a fourth embodiment will now be described with reference to the drawings. Fig. 17 is a side cross-sectional view showing an outline of a structure in which capacitor elements according to the fourth embodiment are stacked.

[0088] 17 , the solid electrolytic capacitor 1C according to the fourth embodiment differs from the solid electrolytic capacitor 1A according to the second embodiment in that it includes a plurality of first capacitor elements 10A, a plurality of second capacitor elements 10B, and a plurality of third capacitor elements 10C. The other configuration of the solid electrolytic capacitor 1C is the same as that of the solid electrolytic capacitor 1A, and a description of similar parts will be omitted.

[0089] The capacitor element laminate 100C is formed by laminating a first capacitor element 10A, a third capacitor element 10C, a second capacitor element 10B, a third capacitor element 10C, a first capacitor element 10A, a third capacitor element 10C, and a second capacitor element 10B in this order.

[0090] In other words, the withstand voltage across both ends of solid electrolytic capacitor 1C is the sum of the withstand voltage of first capacitor element 10A, the withstand voltage of third capacitor element 10C, the withstand voltage of second capacitor element 10B, the withstand voltage of third capacitor element 10C, the withstand voltage of first capacitor element 10A, the withstand voltage of third capacitor element 10C, and the withstand voltage of second capacitor element 10B.

[0091] Even with this configuration, the present invention can realize a solid electrolytic capacitor with a higher breakdown voltage than a conventional solid electrolytic capacitor formed by stacking cathode electrodes and anode electrodes.

[0092] In the above-described embodiments, the number of first capacitor elements 10A and the number of second capacitor elements 10B are the same, but they may be different.

[0093] The number of first capacitor elements 10A, the number of second capacitor elements 10B, and the number of third capacitor elements 10C can be determined by appropriately combining them to obtain a desired withstand voltage (high withstand voltage) and capacitance (high capacitance). Note that if the number of first capacitor elements 10A and the number of second capacitor elements 10B are the same, a non-polar (bipolar) solid electrolytic capacitor can be realized.

[0094] (Explanation of an example of specific materials, etc., for each component of solid electrolytic capacitor 1) (First capacitor element, second capacitor element, third capacitor element) Capacitor element 10 (first capacitor element, second capacitor element, third capacitor element) is realized using, for example, the following materials and thicknesses.

[0095] The electrode 11 (electrode 11C) is made of, for example, a metal such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, or copper, or an alloy containing these metals. The electrode 11 (electrode 11C) is preferably made of aluminum or an aluminum alloy. The electrode 11 (electrode 11C) may be made of any valve metal that exhibits so-called valve action.

[0096] The electrode 11 (electrode 11C) is preferably flat, and the thickness of the core (the center part not reached by the pores of the porous body) of the electrode 11 (electrode 11C) is preferably 5 μm or more and 100 μm or less. The thickness (thickness of one side) of the porous part (the part where the pores of the porous body are formed) is preferably 5 μm or more and 200 μm or less.

[0097] The dielectric layer 12 is preferably an oxide film of the electrode 11 (electrode 11C). For example, when an aluminum foil is used for the electrode 11 (electrode 11C), the dielectric layer 12 is formed by oxidizing the electrode 11 (electrode 11C) in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts or ammonium salts. The thickness of the dielectric layer 12 is preferably 1 nm or more and 100 nm or less.

[0098] The inner layer CP131 may be a PEDOT:PSS layer realized by, for example, a conductive polymer having a skeleton of pyrroles, thiophenes, anilines, or the like, or a conductive polymer having a skeleton of thiophenes, such as PEDOT [poly(3,4-ethylenedioxythiophene)], and composited with polystyrene sulfonic acid (PSS) as a dopant. The inner layer CP131 may be formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 12 using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric portion and drying it.

[0099] The thickness of the outer layer CP 132 is preferably 2 μm or more and 20 μm or less. The material of the outer layer CP 132 is the same as the material of the inner layer CP 131.

[0100] The insulating resin 50 may contain a filler. Examples of suitable resins include epoxy resin, phenol resin, polyimide resin, silicone resin, polyamide resin, and liquid crystal polymer. Examples of suitable fillers include insulating oxide particles such as silica particles, alumina particles, titania particles, and zirconia particles. The maximum diameter of the filler is preferably 10 μm or more and 50 μm or less. For example, a material containing silica particles in a solid epoxy resin and a phenol resin is more preferable.

[0101] The correspondence between the configuration of the present invention and the above-described configuration is described below. [Note] <1> A solid electrolytic capacitor comprising: a sheet laminate formed by laminating first and second capacitor elements, each having a flat-film electrode foil on which a dielectric layer is formed and a solid electrolyte layer on which a dielectric layer is formed, and an insulating resin sealing the sheet laminate, wherein a first pole is formed by drawing out the electrode foil of the first capacitor element from a first end face of the sheet laminate, and a second pole is formed by drawing out the electrode foil of the second capacitor element from a second end face of the sheet laminate opposite to the first end face.

[0102] <2> The solid electrolytic capacitor according to <1>, wherein the first capacitor element is the same as the second capacitor element.

[0103] <3> The solid electrolytic capacitor according to <1> or <2>, further comprising a plurality of flat-film-shaped third capacitor elements each having a dielectric layer and a solid electrolyte layer sequentially formed on a surface of a flat-film-shaped electrode foil, wherein the third capacitor elements are not exposed at the first end surface and the second end surface.

[0104] <4> The solid electrolytic capacitor according to <3>, wherein the third capacitor element is formed between the first capacitor element and the second capacitor element.

[0105] <5> The solid electrolytic capacitor according to any one of <1> to <3>, including: a first external electrode connected to the first pole; and a second external electrode connected to the second pole.

[0106] <6> The solid electrolytic capacitor according to <5>, wherein the first external electrode is formed on a first end surface of the sheet laminate, and the second external electrode is formed on a second end surface of the sheet laminate.

[0107] EA1...first end EA2...second end EB1...first end EB2...second end EC1...first end EC2...second end S11...cutting line 1, 1A, 1B, 1C...solid electrolytic capacitor 10A...first capacitor element 10B...second capacitor element 10C...third capacitor element 11, 11C...electrode 12...dielectric layer 13...CP layer 14...first dam 19C...through hole 19L...through hole 50...insulating resin 61, 62...external electrode 100, 100A, 100B, 100C...capacitor element laminate 131...inner layer CP 132...outer layer CP

Claims

1. A sheet laminate formed by laminating a first capacitor element and a second capacitor element in series, wherein a dielectric layer is formed on the surface of the electrode foil on each flat film, and a solid electrolyte layer is formed on the surface of the dielectric layer; An insulating resin for sealing the sheet laminate; Comprising; A first electrode is formed by pulling out the electrode foil of the first capacitor element from a first end face of the sheet laminate; A second electrode is formed by pulling out the electrode foil of the second capacitor element from a second end face of the sheet laminate facing the first end face; Solid electrolytic capacitor.

2. The solid electrolytic capacitor according to claim 1, wherein the first capacitor element is the same as the second capacitor element.

3. Further comprising a plurality of flat film-shaped third capacitor elements in which a dielectric layer and a solid electrolyte layer are sequentially formed on the surface of a flat film-shaped electrode foil; The solid electrolytic capacitor according to claim 1 or 2, wherein the third capacitor element is not exposed on the first end face and the second end face.

4. The solid electrolytic capacitor according to claim 3, wherein the third capacitor element is formed between the first capacitor element and the second capacitor element.

5. A first external electrode connected to the first electrode; A second external electrode connected to the second electrode; The solid electrolytic capacitor according to claim 1 or 2, comprising.

6. The first external electrode is formed on a first end face of the sheet laminate; The solid electrolytic capacitor according to claim 5, wherein the second external electrode is formed on a second end face of the sheet laminate.

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