Solid electrolytic capacitor manufacturing method and solid electrolytic capacitor
Patent Information
- Application Number
- PCT/JP2025/041287
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-28
- Filing Date
- 2025-11-27
- Publication Date
- 2026-10-01
Smart Images
Figure JP2025041287_01102026_PF_FP_ABST
Abstract
Description
Method for manufacturing solid electrolytic capacitor, and solid electrolytic capacitor
[0001] The present invention relates to a solid electrolytic capacitor having a configuration in which a laminate of a plurality of capacitor elements is molded with an insulating resin.
[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-shaped capacitor elements and a plurality of metal foils (cathodes). The flat film-shaped capacitor element includes a foil-shaped valve metal base, a porous portion of the valve metal base, a dielectric layer formed on a surface of the porous portion, and a solid electrolyte layer formed on a surface of the dielectric layer. The flat film-shaped capacitor elements and the metal foils are alternately stacked, whereby an element laminate is formed. The element laminate is sealed with an insulating resin.
[0003] Patent Document 2 describes a method for manufacturing a solid electrolytic capacitor. The method for manufacturing a solid electrolytic capacitor described in Patent Document 2 includes a step of forming an element assembly, a step of forming a laminate, and a step of singulating the laminate. In the step of forming an element assembly, capacitor elements each having a dielectric layer are arranged in a planar shape. In the step of forming a laminate, a plurality of the element assemblies are stacked. In the singulating step, the plurality of laminates are singulated into individual laminates.
[0004] Patent Document 3 describes a method for manufacturing a multilayer ceramic capacitor. The method for manufacturing a multilayer ceramic capacitor described in Patent Document 3 includes a step of forming a first rod-shaped body, a step of arranging the first rod-shaped body in a resin to form a flat plate block body, a step of cutting the flat plate block body to form a second rod-shaped body, and a step of sintering the second rod-shaped body and removing the resin.
[0005] Japanese Patent Application Laid-Open No. 2019-79866, Japanese Patent Application Laid-Open No. 2020-194825, International Publication No. WO 2022 / 181260
[0006] However, the method for manufacturing solid electrolytic capacitors as exemplified in Patent Documents 1 and 2 has the following steps: (Step 1) Form an element stack. (Step 2) Seal the element stack with an insulating material such as an insulating resin. (Step 3) Cut the sealed element stack in half (primary dicing step). (Step 4) Seal the element stack cut in Step 3 with an insulating material such as an insulating resin. (Step 5) Separate the element stack formed in Step 4 into individual pieces (secondary dicing step).
[0007] The following problems exist in the manufacturing method of multilayer ceramic capacitors in the manufacturing process of solid electrolytic capacitors described in Patent Documents 1 and 2.
[0008] In step 3, the element laminate is cut while leaving a predetermined thickness (half-cut). This is to suppress damage due to the pressure of secondary sealing in step 4, or to facilitate handling when separating into individual pieces in step 5. In other words, the interface between the resin remaining after the half-cut and the resin used for sealing in step 4 is located at an intermediate position in the laminate in the lamination direction. Furthermore, in the secondary dicing process in step 5, the cutting is performed so as to pass through this interface. Therefore, cracks may occur starting from this interface due to the load during the secondary dicing process.
[0009] Furthermore, the element stack requires a resin thickness greater than a specified limit. In other words, the capacitor becomes larger in the thickness direction. Also, if the capacitor thickness is specified, the capacitor capacitance becomes smaller.
[0010] Furthermore, because the laminate is half-cut in step 3, the bottom surface of the laminate is connected. Because the bottom surface of the laminate is connected in this way, there is little flexibility in the arrangement of the laminate. Also, when separating into individual pieces in step 5, it is necessary to determine the cutting surface while considering the width of the laminate (the spacing between the parts to be separated). When considering the width of the laminate in this way, the width of the dicing blade needs to be increased, which limits the number of solid electrolytic capacitors that can be obtained.
[0011] Furthermore, in Patent Document 3, when individualizing the material, the second rod-shaped body is positioned so that its cut surface faces upward. This requires a step of rotating the second rod-shaped body, making the process complicated. Also, if this configuration is applied to a solid electrolytic capacitor, rotating the second rod-shaped body may cause its shape to deform depending on the degree of resin hardening. In other words, the process of handling the second rod-shaped body is difficult, making the process complicated. Moreover, the configuration in Patent Document 3 describes a specific manufacturing method for multilayer ceramic capacitors that have a firing process, and as mentioned above, it is difficult to apply to solid electrolytic capacitors.
[0012] Therefore, when forming solid electrolytic capacitors using the manufacturing methods described in Patent Documents 1 and 2, and when forming solid electrolytic capacitors using the manufacturing method described in Patent Document 3, there is a risk that manufacturing efficiency will decrease and productivity will be lower in terms of cost.
[0013] Therefore, an object of the present invention is to provide a method for efficiently manufacturing a solid electrolytic capacitor and a solid electrolytic capacitor thereof.
[0014] The method for manufacturing a solid electrolytic capacitor according to this invention comprises a capacitor element formation step, a through-hole formation step for the anode, a through-hole formation step for the cathode, a first sheet laminate formation step, a first sealing step, a second sheet laminate formation step, an arrangement step, a second sealing step, and a piece formation step.
[0015] In the capacitor element formation process, a dielectric layer and a solid electrolyte layer are sequentially formed on the surface of a flat anode electrode foil to form multiple flat capacitor elements. In the anode through-hole formation process, anode through-holes are formed that penetrate the multiple flat capacitor elements in the thickness direction. In the cathode through-hole formation process, cathode through-holes are formed that penetrate the flat cathode electrode foil in the thickness direction. In the first sheet laminate formation process, a first sheet laminate having a top surface and a bottom surface opposite the top surface is formed by alternately laminating multiple flat capacitor elements and flat cathode electrode foils with a solid electrolyte layer in between. In the first sealing process, the top surface of the first sheet laminate is sealed with a first resin, and the anode through-holes and cathode through-holes are filled with the first resin. In the second sheet laminate formation process, the first sheet laminate is cut along a first cutting line perpendicular to the top and bottom surfaces to form multiple second sheet laminates. In the placement process, the multiple second sheet laminates are placed on a release sheet. In the second sealing step, the entire top surface and the sides along the first cutting line of the second sheet laminate, where the first resin is formed, are covered with an insulating second resin. In the individualization step, while placed on a release sheet, the second sheet laminate, sealed with the first and second resins, is cut along the second cutting line and a third cutting line perpendicular to the second cutting line to form individual capacitor laminates.
[0016] In this manufacturing method, when forming the second sheet laminate, the sheet is cut so that all sides (cut surfaces) are exposed (full cut). In the second sealing step, the second resin covers the entire first resin formed on the top surface and the sides (cut lines). Therefore, the cut lines in the individualization step do not overlap with the resin interface, thus suppressing cracking during individualization.
[0017] Furthermore, because the second sheet laminate is fully cut, there is greater flexibility in positioning the second sheet laminate on the release sheet. In other words, there is no restriction on the width of the dicing blade in the second sheet laminate formation process. This allows for a larger number of solid electrolytic capacitors to be obtained.
[0018] Furthermore, after placing the second sheet laminate on the release sheet, the second sheet laminate is fixed in place. In other words, since rotational movement is unnecessary, it becomes possible to form solid electrolytic capacitors more easily and efficiently.
[0019] The solid electrolytic capacitor of this invention comprises a capacitor laminate, a first resin, and a second resin. The capacitor laminate is formed by alternately stacking a plurality of flat capacitor elements, each having a dielectric layer and a solid electrolyte layer on the surface of a flat anode electrode foil, and a flat cathode electrode foil, with a solid electrolyte layer in between. The laminate has a top surface, a bottom surface opposite the top surface, and sides connected to the top and bottom surfaces. The first resin covers the top and bottom surfaces of the capacitor laminate. The second resin covers the first resin formed on the top surface and the sides.
[0020] Multiple flat film capacitor elements have through-holes for the anode that penetrate in the thickness direction. A flat film cathode electrode foil has through-holes for the cathode that penetrate in the thickness direction. The anode and cathode through-holes are filled with a first resin.
[0021] In this solid electrolytic capacitor, the interface between the first resin and the second resin is located on the bottom surface. In other words, the first resin formed on the top surface of the solid electrolytic capacitor and the sides are covered by the second resin. That is, because it is sealed by the continuous application of the same resin, damage originating from the resin interface is easily suppressed.
[0022] Furthermore, in conventional configurations such as those described in the patent document, the resin interface is exposed on the side surface. When mounted on a substrate, moisture (water vapor) easily permeates through this interface. However, because the side surface is covered only with the second resin, the interface is not exposed on the side surface. In other words, the degree to which moisture (water vapor) permeates from the side surface can be suppressed. Therefore, the intrusion of moisture into the interior of the solid electrolytic capacitor is suppressed. As a result, a highly reliable solid electrolytic capacitor can be realized.
[0023] This invention provides a method for efficiently manufacturing solid electrolytic capacitors, and a highly reliable solid electrolytic capacitor manufactured by this manufacturing method.
[0024] [Correction based on Rule 91 04.12.2025] Figure 1 is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to the first embodiment. Figures 2(A) and 2(B) are side cross-sectional views showing the configuration of a set of capacitor elements and cathode electrodes before individualization. Figure 3 is a flowchart showing an example of a schematic flow of the manufacturing method of a solid electrolytic capacitor according to this embodiment. Figure 4(A) is an external perspective view showing the state in which the capacitor element sheet and the cathode electrode sheet are laminated, and Figure 4(B) is an external perspective view showing the state in which they are sealed with insulating resin. Figure 5 is a flowchart showing an example of the process of forming the capacitor element sheet. Figures 6(A), 6(B), 6(C), and 6(D) are schematic diagrams showing the process of forming the capacitor elements of a solid electrolytic capacitor according to the first embodiment. Figure 7 is an external view of the capacitor elements in a multi-layer state. Figure 8 is an external perspective view showing the shape of the cathode electrode before individualization. Figure 9 is an external perspective view in a multi-layer state showing the shape of the cathode electrode before individualization. Figure 10 is a flowchart showing an example of the process of forming the first sheet laminate. Figure 11 is an exploded perspective view showing the state in which the capacitor element sheet and the cathode electrode sheet are stacked. Figure 12 is a flowchart showing an example of the process for forming the second sheet stack. Figure 13 is a schematic diagram of the first sheet stack. Figure 14 is a diagram showing the state in which the second sheet stack is placed on a release sheet. Figures 15(A), 15(B), 15(C), and 15(D) are schematic diagrams showing the process for forming the second sheet stack. Figure 16 is a schematic diagram showing the process for separating solid electrolytic capacitors into individual pieces. Figure 17(A) is a cross-sectional view of a solid electrolytic capacitor, Figure 17(B) is a view of Figure 17(A) from the top side, and Figure 17(C) is a view of Figure 17(A) from the bottom side. Figure 18 is a diagram showing the arrangement of the second sheet stack in the second embodiment. Figures 19(A), 19(B), and 19(C) are diagrams showing the process for forming a solid electrolytic capacitor in the second embodiment. Figure 20(A) is a cross-sectional view of a solid electrolytic capacitor, Figure 20(B) is a view of Figure 20(A) from the top, and Figure 20(C) is a view of Figure 20(A) from the bottom. Figure 21 is a perspective view of a solid electrolytic capacitor. Figure 22 is a perspective view of a solid electrolytic capacitor. Figure 23 is a plan view of a solid electrolytic capacitor.Figure 24 is a left side view of a solid electrolytic capacitor. Figure 25 is a front view of a solid electrolytic capacitor. Figure 26 is a right side view of a solid electrolytic capacitor. Figure 27 is a rear view of a solid electrolytic capacitor. Figure 28 is a bottom view of a solid electrolytic capacitor. Figure 29(A) is a reference diagram relating to a top view of a solid electrolytic capacitor. Figure 29(B) is a reference diagram relating to a left side view. Figure 29(C) is a reference diagram relating to a front view. Figure 29(D) is a reference diagram relating to a right side view. Figure 29(E) is a reference diagram relating to a rear view. Figure 29(F) is a reference diagram relating to a bottom view. Figure 30 is a reference diagram relating to a bottom view of a solid electrolytic capacitor.
[0025] [First Embodiment] A method for manufacturing a solid electrolytic capacitor according to the first embodiment of the present invention, and a solid electrolytic capacitor manufactured by this manufacturing method, will be described with reference to the figures.
[0026] (General description of the configuration of the solid electrolytic capacitor 1) First, the structure of the solid electrolytic capacitor manufactured by the manufacturing method of the solid electrolytic capacitor according to the embodiment of the present invention will be described. Figure 1 is a side cross-sectional view showing the configuration of the solid electrolytic capacitor according to the first embodiment. Note that in Figure 1, only the insulating resin and the external electrodes are hatched for clarity. Figures 2(A) and 2(B) are side cross-sectional views showing the configuration of the capacitor element and cathode electrode set before individualization.
[0027] As shown in Figures 1, 2(A), and 2(B), the solid electrolytic capacitor 1 comprises a capacitor element laminate 100, an insulating resin 50, an external electrode 61, and an external electrode 62. The capacitor element laminate 100 comprises a plurality of flat film capacitor elements 10 and a plurality of flat film cathode electrodes 20. Note that the number of flat film capacitor elements 10 and cathode electrodes 20 in the configuration shown in Figure 1 is not limited to this. The side cross-sectional views in Figures 1, 2(A), and 2(B) are cross-sectional views of the capacitor element laminate 100 in Figure 1 taken from planes perpendicular to the top surface 101 and bottom surface 102. These flat film cathode electrodes 20 correspond to the "cathode electrode foil" in the present invention. The structure of the insulating resin 50 will be described in more detail later.
[0028] As shown in Figure 2(B), the capacitor element 10 comprises a flat film-shaped anode electrode 11, a dielectric layer 12, and a CP layer (solid electrolyte layer) 13. This flat film-shaped anode electrode 11 corresponds to the "anode electrode foil" in the present invention.
[0029] Although detailed structural illustrations are omitted in Figures 2(A) and 2(B), the anode electrode 11 has numerous pores. In other words, the anode electrode 11 is porous. The ratio of the thickness of the porous portion on one side of the anode 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 anode electrode 11. In Figures 2(A) and 2(B), detailed structural illustrations of the anode electrode 11 are omitted, so the dielectric layer 12 is schematically shown as covering the macroscopic surface of the anode electrode 11. In reality, the dielectric layer 12 covers not only the macroscopic surface of the anode electrode 11 but also the inner surfaces of the numerous pores in the anode electrode 11.
[0030] The CP layer 13 covers the surface of the dielectric layer 12. A frame-shaped CP dam 14 is formed around the outer periphery of the CP layer 13. The CP dam 14 is insulating. The CP dam 14 restricts the area where the CP layer 13 is formed.
[0031] The CP layer 13 has a laminated structure consisting of an inner CP (inner solid electrolyte layer) 131 and an outer CP (outer solid electrolyte layer) 132. The inner CP 131 is formed on the surface of the dielectric layer 12, and the outer CP 132 is formed on the surface of the inner CP 131.
[0032] Multiple capacitor elements 10 and multiple cathode electrodes 20 are stacked alternately so that their respective flat surfaces are parallel and overlap when viewed from above. In this case, the outer layer CP132 of the capacitor elements and the cathode electrodes 20 are directly connected. In the structure shown in Figure 2(A), the outer layer CP132 of the capacitor elements 10 and the cathode electrodes 20 are bonded together so that they are in contact. As a result, adjacent capacitor elements 10 and cathode electrodes 20 are bonded together and electrically connected. By stacking the capacitor elements 10 and cathode electrodes 20 in this way without using adhesive, the thickness of the solid electrolytic capacitor 1 can be reduced. However, if the adhesive does not affect the thickness of the solid electrolytic capacitor 1, the capacitor elements 10 and cathode electrodes 20 may be bonded together using an adhesive. In this case, it is preferable that the adhesive contains carbon.
[0033] In this stacked state, the first ends 10E1 (see Figure 1) of the multiple capacitor elements 10 are in approximately the same position when viewed from the side. Similarly, the second ends 10E2 (see Figure 1) of the multiple capacitor elements 10 are in approximately the same position when viewed from the side. Furthermore, the first ends 20E1 (see Figure 1) of the multiple cathode electrodes 20 are in approximately the same position when viewed from the side. Similarly, the second ends 20E2 (see Figure 1) of the multiple cathode electrodes 20 are in approximately the same position when viewed from the side.
[0034] The first ends 10E1 of the multiple capacitor elements 10 and the second ends 20E2 of the multiple cathode electrodes 20 are positioned on the first end 100E1 side of the capacitor element stack 100. The first ends 10E1 of the multiple capacitor elements 10 protrude outward beyond the second ends 20E2 of the multiple cathode electrodes 20.
[0035] The second ends 10E2 of the multiple capacitor elements 10 and the first ends 20E1 of the multiple cathode electrodes 20 are positioned on the second end 100E2 side of the capacitor element stack 100. The first ends 20E1 of the multiple cathode electrodes 20 protrude outward from the second ends 10E2 of the multiple capacitor elements 10.
[0036] This structure realizes a capacitor element laminate 100 having a top surface 101 and a bottom surface 102 at both ends in the stacking direction of the multiple capacitor elements 10 and multiple cathode electrodes 20. In this case, the capacitor element laminate 100 may be placed on a resin substrate.
[0037] The capacitor element laminate 100 is sealed with an insulating resin 50. In this case, the insulating resin 50 on the bottom side of the capacitor element laminate 100 may include a resin substrate as described above. A more specific sealing process will be described later.
[0038] The external electrode 61 covers the first end of the insulating resin 50 and the first end 10E1 of the anode electrode 11. The external electrode 61 is connected to the first end 10E1 of the anode electrode 11 of the multiple capacitor elements 10. The external electrode 62 covers the second end of the insulating resin 50 and the first end 20E1 of the cathode electrode 20. The external electrode 62 is connected to the first end 20E1 of the multiple cathode electrodes 20.
[0039] The solid electrolytic capacitor 1 is realized with the above configuration.
[0040] (Method for Manufacturing Solid Electrolytic Capacitor 1) The solid electrolytic capacitor 1 having the above-described configuration is manufactured, for example, as follows. Figure 3 is a flowchart showing an example of a schematic flow of the method for manufacturing a solid electrolytic capacitor according to this embodiment. Figure 4(A) is an external perspective view showing the state in which the capacitor element sheet and the cathode electrode sheet are stacked, and Figure 4(B) is an external perspective view showing the state in which it is sealed with insulating resin.
[0041] A capacitor element sheet is formed (Figure 3: S11). The capacitor element sheet is formed with multiple capacitor elements 10 arranged on it, each forming a different solid electrolytic capacitor 1 (see Figure 7, described later).
[0042] Next, as shown in FIG. 4(A), a capacitor element sheet and a cathode electrode sheet are laminated to form a first sheet laminate 110 (FIG. 3: S12). The cathode electrode sheet is formed with a plurality of cathode electrodes 20, which form different solid electrolytic capacitors 1 respectively, arranged in an array. Thereby, a structure in which a plurality of capacitor element laminates 100 are two-dimensionally arranged in a plane is formed. In other words, the first sheet laminate 110 is a structure in which a plurality of capacitor element laminates 100 are two-dimensionally arranged in a plane.
[0043] Next, as shown in FIG. 4(B), the first sheet laminate 110 is sealed with an insulating resin 51 (FIG. 3: S13). In this case, the first sheet laminate 110 may be sealed while being placed on a resin substrate. In this case, the resin substrate is preferably made of the same resin as the insulating resin 51, but may be made of a different type of resin. In that case, it is preferable that the coefficient of linear expansion of the insulating resin 51 is the same as or close to the coefficient of linear expansion of the resin constituting the resin substrate. Further, as shown in FIG. 11 described later, the sheet laminate is provided with a through hole penetrating from the upper surface to the lower surface of the first sheet laminate 110, and resin sealing is performed by, for example, compression molding. The insulating resin 51 corresponds to the "first resin" in the present invention. Further, when the first sheet laminate 110 is placed on a resin substrate, the insulating resin 51 and the resin substrate correspond to the "first resin" in the present invention.
[0044] Next, the first sheet laminate 110 is cut (divided) into strips along the cutting line S11 (see FIG. 13) (FIG. 3: S14). The first sheet laminate 110 divided into strips forms a plurality of second sheet laminates 120. A more specific structure of the second sheet laminate 120 will be described later. This cutting line S11 corresponds to the "first cutting line" of the present invention.
[0045] The term "strip shape" refers to a rectangular shape in plan view (in this case, when viewed in the direction in which the capacitor element 10 and the cathode electrode 20 are laminated), and means a rectangular parallelepiped shape in which laminates that will later become individual solid electrolytic capacitors are arranged in the longitudinal direction and have a predetermined thickness (length in the lamination direction).
[0046] Next, as shown in FIG. 14 described later, the plurality of second sheet laminates 120 are arranged on the release sheet 550 (FIG. 3: S15). A more specific structure will be described later.
[0047] Next, as shown in FIG. 15(B) described later, the second sheet laminate 120 is sealed with an insulating resin 52 (FIG. 3: S16). As a result, each side surface along the cutting line S11 of the plurality of second sheet laminates 120 and the top surface of the plurality of second sheet laminates 120 (the top surface on which the insulating resin 51 is formed) are covered. Until the sealing with the insulating resin 52, the process is performed in a multi-state before the solid electrolytic capacitors 1 are singulated (a state in which a plurality of elements that will become the solid electrolytic capacitors 1 are arranged). Note that the insulating resin 52 corresponds to the "second resin" in the present invention.
[0048] Next, the sheet laminate sealed with the insulating resin 52 is cut and singulated (FIG. 3: S17). Specifically, cutting is performed along cutting lines S21 and E21 shown in FIG. 16 described later. As a result, a plurality of solid electrolytic capacitors 1 in a state where external electrodes are not formed (referred to as capacitor laminates of the solid electrolytic capacitors 1) are formed. In other words, individual pieces are formed in which the anode electrode 11 and the cathode electrode 20 are covered with the insulating resin 50, and the anode electrode 11 and the cathode electrode 20 are not undesirably exposed to the outside. The cutting line S21 corresponds to the "second cutting line" of the present invention, and the cutting line E21 corresponds to the "third cutting line" of the present invention.
[0049] Next, external electrodes 61 and 62 are formed on the end surfaces of the capacitor laminate of the solid electrolytic capacitor 1 (FIG. 3: S18).
[0050] Next, each step will be described more specifically. (Step of forming capacitor element sheet) FIG. 5 is a flowchart showing an example of the step of forming a capacitor element sheet. FIGS. 6(A), 6(B), 6(C), and 6(D) are schematic diagrams showing the step of forming the capacitor element of the solid electrolytic capacitor according to the first embodiment. FIG. 7 is an external view of the capacitor element in a multi-state. Note that FIGS. 6(A), 6(B), 6(C), and 6(D) show a part of the capacitor element in the multi-state.
[0051] As shown in Figure 6(A), a conversion treatment is performed on the anode electrode 11 to form a dielectric layer 12 (Figure 5: S111). At this time, numerous holes are formed on the surface of the anode electrode 11 by etching, and the area near the surface of the anode electrode 11 becomes porous. The dielectric layer 12 covers the surface of the anode electrode 11, including the inner surfaces of the holes.
[0052] Next, a CP layer (solid electrolyte layer) 13 is formed on the surface of the dielectric layer 12 (Figure 5: S112). More specifically, as shown in Figure 6(B), a CP dam 14 having a frame-shaped opening is formed. Then, as shown in Figure 6(C), a 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 CP dam 14.
[0053] Next, as shown in Figure 6(D), anode through-holes are formed in the anode electrode 11 (Figure 5: S113). More specifically, as shown in Figure 6(D), a plurality of cylindrical anode through-holes 19C and groove-shaped anode through-holes 19L are formed in the anode electrode 11. In this case, the plurality of cylindrical anode through-holes 19C and groove-shaped anode through-holes 19L penetrate not only the anode electrode 11 but also the CP dam 14. The plurality of cylindrical anode through-holes 19C and groove-shaped anode through-holes 19L are arranged alternately along the direction of the cutting line where the portions that will become the plurality of anode electrodes 11 are aligned. The plurality of cylindrical anode through-holes 19C are formed at positions that realize the first end 10E1 of the anode electrode 11. The groove-shaped anode through-holes 19L are formed at positions that straddle adjacent portions that will become the anode electrode 11 and at positions that realize the second end 10E2 of adjacent anode electrodes 11.
[0054] As shown in Figure 7, this structure is implemented in a multi-state configuration in which multiple capacitor elements 10 (structures consisting of an anode electrode 11, a dielectric layer 12, a CP layer 13, and a CP dam 14) are arranged in two dimensions.
[0055] In the configuration described above, step S112 shows the formation of the CP dam 14, followed by step S113 in which an anode through-hole is formed in the anode electrode 11. However, it is also possible to form the CP dam 14 after the anode through-hole is formed in the anode electrode 11, without blocking the anode through-hole.
[0056] (Cathode electrode sheet formation process) Figure 8 is an external perspective view showing the shape of the cathode electrode before individualization. Figure 9 is an external perspective view showing the shape of the cathode electrode in a multi-layer state before individualization.
[0057] As shown in Figures 8 and 9, the cathode electrode 20 has a plurality of cylindrical cathode through holes 29C and a groove-shaped cathode through hole 29L. The plurality of cylindrical cathode through holes 29C and the groove-shaped cathode through hole 29L are arranged alternately along the direction of the cutting line where the portions that will become the cathode electrode 20 are aligned.
[0058] Multiple cylindrical cathode through-holes 29C are formed at positions that realize the first end 20E1 of the cathode electrode 20. Groove-shaped cathode through-holes 29L are formed at positions that straddle adjacent cathode electrode portions 20 and at positions that realize the second end 20E2 of adjacent cathode electrodes 20.
[0059] Furthermore, the shapes of the multiple cylindrical anode through-holes 19C, the groove-shaped anode through-holes 19L, the multiple cylindrical cathode through-holes 29C, and the groove-shaped cathode through-holes 29L are very simple. In other words, these through-holes can be easily formed.
[0060] Furthermore, the widths of the groove-shaped anode through-hole 19L and the groove-shaped cathode through-hole 29L can be set to any size. More specifically, they can be arbitrarily determined within a range that prevents short circuits between adjacent capacitor elements before they are separated into individual pieces.
[0061] (Formation process of the first sheet laminate) Figure 10 is a flowchart showing an example of the formation process of the first sheet laminate. Figure 11 is an exploded perspective view showing a structure in which capacitor element sheets and cathode electrodes are laminated.
[0062] As shown in Figure 11, capacitor element sheets and cathode electrode sheets are stacked alternately (Figure 10: S121). More specifically, the capacitor element sheets and cathode electrode sheets are stacked in such a way that the following conditions are met. By stacking the capacitor element sheets and cathode electrode sheets in this way, the first sheet stack 110 is formed.
[0063] - When viewed in the stacking direction (thickness direction), the multiple cylindrical anode through holes 19C in the capacitor element sheet and the groove-shaped cathode through holes 29L in the cathode electrode sheet overlap (see Figure 11). - When viewed in the stacking direction (thickness direction), the groove-shaped anode through holes 19L in the capacitor element sheet and the multiple cylindrical cathode through holes 29C in the cathode electrode sheet overlap (see Figure 11). Therefore, multiple through holes are formed in the first sheet laminate 110 that penetrate from the top surface to the bottom surface of the first sheet laminate 110.
[0064] Next, the first sheet laminate 110 is heated and pressurized (Figure 10: S122).
[0065] (Formation, arrangement, resin sealing, and individualization process of the second sheet laminate) Figure 12 is a flowchart showing an example of the process of forming the second sheet laminate. Figure 13 is a schematic diagram showing the structure of the second sheet laminate. Figure 14 is a diagram showing the second sheet laminate placed on a release sheet. Figures 15(A), 15(B), 15(C), and 15(D) are schematic diagrams showing the process of forming the second sheet laminate. Figure 16 is a schematic diagram showing the process of individualizing a solid electrolytic capacitor. Figure 17(A) is a cross-sectional view of a solid electrolytic capacitor, Figure 17(B) is a view of Figure 17(A) from the top side, and Figure 17(C) is a view of Figure 17(A) from the bottom side.
[0066] First, as shown in Figures 4(B) and 13, the first sheet laminate 110, sealed with insulating resin 51, is cut along the cutting line S11 (Figure 12: S131). This forms a strip-shaped second sheet laminate 120. The first sheet laminate 110 is cut, for example, using a guillotine blade. By using a guillotine blade, the second sheet laminate 120 is cut accurately and efficiently. Furthermore, this cutting method can suppress unwanted dragging of the electrodes at the cut surface and prevent short circuits between the anode electrode 11 and the cathode electrode 20. The first sheet laminate 110 may also be cut using an ultrasonic cutter.
[0067] Next, as shown in Figures 14 and 15(A), the second sheet laminate 120 is placed on the release sheet 550 (Figure 12: S132). More specifically, the multiple second sheet laminates 120 are each placed on the release sheet 550, for example, by pick and place. At this time, the second sheet laminates 120 are placed on the release sheet 550 in a state in which they can stand upright. The state in which the second sheet laminate 120 can stand upright means that the stacking direction of the capacitor elements 10 and cathode electrodes 20 of the second sheet laminate 120 is approximately perpendicular to the surface of the release sheet 500 when it is placed on the release sheet 550.
[0068] Furthermore, it is preferable that the second sheet laminates 120 are arranged substantially evenly with predetermined intervals between them. These gaps due to the predetermined intervals are sealed with insulating resin 52. It is preferable that these predetermined intervals are wide enough for the cutting lines during individualization to pass through and for sufficient sealing resin to be formed. This substantially even arrangement includes configurations that are not unintentionally uniform due to manufacturing errors, and does not require a perfectly uniform arrangement.
[0069] Note that the arrangement method is not limited to pick and place. For example, the following method can also be used. It is preferable that the release sheet 550 is a stretchable sheet. In this case, multiple second sheet laminates 120 are placed on the release sheet 550. At this time, the second sheet laminates 120 are placed with their sides along the cut surfaces substantially in contact with each other. In this state, the second sheet laminates 120 are stretched in a direction perpendicular to the cut surfaces. As a result, multiple second sheet laminates 120 are placed at predetermined intervals. By making the release sheet 550 a stretchable sheet in this way, it is easy to create a state in which the sides (cut surfaces) of each second sheet laminate 120 are exposed.
[0070] Next, as shown in Figure 15(B), the multiple second sheet laminates 120 placed on the release sheet 550 are sealed with insulating resin 52 (Figure 12: S133).
[0071] Next, as shown in Figure 15(C), the product is heated and pressurized while sealed with the insulating resin 52 (Figure 12: S134). The release sheet 550 is preferably peeled off using the heat generated by this heating and pressurizing. In other words, it is preferable that the release sheet 550 is a heat-release sheet.
[0072] Next, as shown in Figures 15(D) and 16, the material is separated into individual pieces along the cutting lines E21 and S21 (Figure 12: S135). In this way, a solid electrolytic capacitor is formed without external electrodes. At this time, the cutting line S21 is defined between adjacent second sheet laminates 120. More specifically, it is preferable that the cutting line S21 is defined at approximately the center position of adjacent second sheet laminates 120.
[0073] Through this process, the solid electrolytic capacitor 1 can be formed easily and efficiently.
[0074] Furthermore, in step S131, the first sheet laminate 110 sealed with insulating resin 51 is cut along the cutting line S11 so that the entire side surface along the cutting line is exposed. In other words, it is possible to suppress an increase in the thickness of the solid electrolytic capacitor 1.
[0075] Next, the detailed structure of the solid electrolytic capacitor 1 will be described using Figures 17(A), 17(B), and 17(C). Figure 17(A) is a cross-sectional view of the solid electrolytic capacitor, Figure 17(B) is a view of Figure 17(A) from the top side, and Figure 17(C) is a view of Figure 17(A) from the bottom side. As mentioned above, the insulating resin 51 on the bottom side may be a pre-prepared resin substrate. Preferably, the resin substrate is made of a resin with the same components as the insulating resin 51. As mentioned above, sealing with the insulating resin 51 is performed by compression molding, for example, so the anode through-hole and cathode through-hole mentioned above are also filled with the insulating resin 51.
[0076] As shown in Figure 17(A), the solid electrolytic capacitor 1 comprises a capacitor laminate, an insulating resin 51, and an insulating resin 52. As shown in Figure 17(B), when the solid electrolytic capacitor 1 is viewed from above, the top surface is covered with the insulating resin 52. That is, the insulating resin 52 covers the top surface on which the insulating resin 51 is formed. As shown in Figure 17(C), when the solid electrolytic capacitor 1 is viewed from below, the interface between the insulating resin 51 and the insulating resin 52 is exposed.
[0077] In other words, the insulating resin 52 covers the entire top surface (the top surface on which the insulating resin 51 is formed) and the sides (the sides excluding the parts on which the external electrodes are formed) of the solid electrolytic capacitor 1. Furthermore, the interface between the insulating resin 51 and the insulating resin 52 is exposed on the bottom surface.
[0078] With this configuration, the sides of the capacitor laminate of the solid electrolytic capacitor 1 are sealed by a continuous insulating resin 52. In other words, compared to a conventional configuration in which the interface of resins formed by different processes is exposed on the side, damage to the side is more easily suppressed.
[0079] Furthermore, when mounted on a circuit board, moisture (water vapor) can easily permeate through the resin interface. However, because the sides are covered with insulating resin 51, the degree to which moisture (water vapor) permeates can be suppressed. Therefore, the intrusion of moisture into the interior of the solid electrolytic capacitor is suppressed. As a result, a highly reliable solid electrolytic capacitor can be realized.
[0080] Furthermore, it is preferable that insulating resin 51 and insulating resin 52 are made of the same component. This reduces the difference in the coefficient of linear expansion, suppressing fracture of the interface between insulating resin 51 and insulating resin 52 due to external stress during heating and pressurization. In other words, the strength of the solid electrolytic capacitor 1 can be improved.
[0081] Furthermore, the insulating resin 51 and insulating resin 52 may be made of different components, provided that the strength of the solid electrolytic capacitor 1 is not compromised. In this case, it is preferable that the insulating resin 51 has lower rigidity than the insulating resin 52. This allows the insulating resin 51 to relieve stress even when the internal pressure of the solid electrolytic capacitor 1 increases.
[0082] Furthermore, by using this manufacturing method, the spacing between multiple second sheet laminates in the first sheet laminate can be shortened. This allows for a greater number of second sheet laminates to be formed from a first sheet laminate of a predetermined area.
[0083] [Second Embodiment] A method for manufacturing a solid electrolytic capacitor according to Modification 1 of the present invention, and a solid electrolytic capacitor manufactured by this method, will be described with reference to the figures.
[0084] Figure 18 is a diagram showing the arrangement of the second sheet laminate in the second embodiment. Figures 19(A), 19(B), and 19(C) are diagrams showing the process of forming a solid electrolytic capacitor in the second embodiment. Figure 18 is a plan view from the bottom side of the second sheet laminate 120, with the second sheet laminate 120 placed on the support 560.
[0085] The solid electrolytic capacitor 1A according to the second embodiment differs in the shape of the insulating resin 52 and the method of forming the solid electrolytic capacitor 1A. Other components of the solid electrolytic capacitor according to the second embodiment are the same as those of the solid electrolytic capacitor according to the first embodiment, and descriptions of the similar parts will be omitted.
[0086] As shown in Figures 18 and 19(A), the second sheet laminate 120 is placed on a support 560. The support 560 is made of a thermosetting resin such as glass epoxy resin. At this time, the multiple second sheet laminates 120 are aligned and fixed to the support 560. As will be described later, the support 560 is shaped so that when the multiple second sheet laminates 120 are sealed with insulating resin 52, the insulating resin 52 can flow into the bottom side of the second sheet laminates 120. Similar to the first embodiment, it is preferable that the multiple second sheet laminates 120 are arranged parallel to each other with a predetermined interval between them.
[0087] Furthermore, the multiple second sheet laminates 120 are fixed in an orientation perpendicular to the long side direction (parallel to the short side direction) of the support 560. This reduces the contact area between the multiple second sheet laminates 120 and the support 560, allowing for efficient arrangement.
[0088] Furthermore, it is preferable that the support 560 has an adhesive material made of a thermosetting resin or the like on the surface that comes into contact with the plurality of second sheet laminates 120. The adhesiveness of the support 560 allows the plurality of second sheet laminates 120 to be effectively fixed by the support 560.
[0089] Figure 18 shows an example in which the second sheet laminate 120 is fixed by a single support 560. However, multiple support 560s may be provided if they do not affect the number of solid electrolytic capacitors 1A that can be obtained when the capacitor is divided into individual pieces. In other words, if multiple support 560s are provided, it is preferable that the multiple support 560s are formed in positions that overlap in the thickness direction (lamination direction) of the second sheet laminate 120. This minimizes the influence of the support 560s on the number of solid electrolytic capacitors 1A that can be obtained.
[0090] As described above, the second sheet laminate 120 is sealed with insulating resin 52 while fixed to the support 560. As a result, the entire top surface, bottom surface, and sides of the second sheet laminate 120, where the first resin is formed, are covered with insulating resin 52. In other words, the support 560 acts as a spacer. As a result, as shown in Figure 19(B), the top surface, bottom surface, and sides of the second sheet laminate 120 are all covered with insulating resin 52, except for the parts that are in contact with the support 560.
[0091] In this state, as shown in Figure 19(C), the second sheet laminate 120 is separated into individual pieces. This makes it possible to realize a solid electrolytic capacitor 1A in which the top surface, part of the side surface, and the bottom surface are covered with insulating resin 52, as shown in Figure 20(A). In other words, similar to the first embodiment, the solid electrolytic capacitor 1A can be easily and efficiently formed by using the above-described process.
[0092] The insulating resin 52 covering the top surface, part of the sides, and the bottom surface of the solid electrolytic capacitor 1A has no interface. In other words, even if stress is applied to the solid electrolytic capacitor 1A from the outside or inside, cracking of the insulating resin 52 is unlikely to occur.
[0093] With this configuration, the insulating resin 52 covering the top, sides, and bottom surfaces is made of the same continuous resin. In other words, compared to conventional configurations where the resin interface is exposed on the sides, damage to the sides is more easily suppressed.
[0094] Furthermore, when mounted on a substrate, moisture (water vapor) can easily permeate through the resin interface. However, in the second embodiment, since the interface between the insulating resin 51 and the insulating resin 52 is not exposed to the outside on the top, side, and bottom surfaces, the degree to which moisture (water vapor) permeates can be suppressed. Therefore, the intrusion of moisture into the interior of the solid electrolytic capacitor is suppressed. As a result, a highly reliable solid electrolytic capacitor can be realized.
[0095] Furthermore, it is preferable that the support 560 is positioned so as not to overlap the capacitor element laminate 100. As a result, the solid electrolytic capacitor 1A does not include the support 560, thus enabling the realization of a solid electrolytic capacitor with even higher reliability.
[0096] (Structure of Solid Electrolytic Capacitors) Next, we will explain the structure of solid electrolytic capacitors.
[0097] Figure 21 is a perspective view of the solid electrolytic capacitor from the top. Figure 22 is a perspective view of the solid electrolytic capacitor from the bottom. Figure 23 is a top view of the solid electrolytic capacitor. Figure 24 is a left side view of the solid electrolytic capacitor. Figure 25 is a front view of the solid electrolytic capacitor. Figure 26 is a right side view of the solid electrolytic capacitor. Figure 27 is a rear view of the solid electrolytic capacitor. Figure 28 is a bottom view of the solid electrolytic capacitor.
[0098] [Correction based on Rule 91 04.12.2025] Figure 29(A) is a reference diagram relating to the plan view of a solid electrolytic capacitor. Figure 29(B) is a reference diagram relating to the left side view. Figure 29(C) is a reference diagram relating to the front view. Figure 29(D) is a reference diagram relating to the right side view. Figure 29(E) is a reference diagram relating to the rear view. Figure 29(F) is a reference diagram relating to the bottom view. Figure 30 is a reference diagram relating to the bottom view of a solid electrolytic capacitor.
[0099] (Description of specific materials and other examples for each component of the solid electrolytic capacitor 1) (Capacitor element 10) The capacitor element 10 is realized using, for example, the following materials and thicknesses.
[0100] The anode electrode 11 is made of, for example, a single metal such as aluminum, tantalum, niobium, titanium, zirconium, or magnesium, or an alloy containing these metals. Preferably, the anode electrode 11 is aluminum or an aluminum alloy. The anode electrode 11 can be any valve-acting metal that exhibits so-called valve action.
[0101] The anode electrode 11 is preferably flat, and the thickness of the core portion of the anode electrode 11 (the central part not reached by the pores of the porous material) is preferably 5 μm or more and 100 μm or less. The thickness of the porous portion (the portion where the pores of the porous material are formed) (thickness on one side) is preferably 5 μm or more and 200 μm or less.
[0102] The dielectric layer 12 is preferably made of an oxide film of the anode electrode 11. For example, when aluminum foil is used for the anode electrode 11, the dielectric layer 12 is formed by oxidation in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts, ammonium salts, etc. The thickness of the dielectric layer 12 is preferably 1 nm or more and 100 nm or less.
[0103] The inner layer CP131 may be realized using, for example, a conductive polymer with a backbone of pyrroles, thiophenes, anilines, etc., or a conductive polymer with a backbone of thiophenes such as PEDOT [poly(3,4-ethylenedioxythiophene)], and may also be a PEDOT:PSS layer compounded with polystyrene sulfonic acid (PSS) as a dopant. The inner layer CP131 may be formed by, for example, using a processing solution containing a monomer such as 3,4-ethylenedioxythiophene to form a polymerized film of poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer 12, or by applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric part and drying it.
[0104] The thickness of the outer layer CP132 is preferably 2 μm or more and 20 μm or less. The material of the outer layer CP132 is the same as the material of the inner layer CP131.
[0105] The cathode electrode 20 is preferably made of aluminum or an aluminum alloy. The thickness of the cathode electrode 20 is, for example, about the same as the thickness of the anode electrode 11.
[0106] The insulating resin 50 (insulating resin 51, insulating resin 52) may contain fillers. Preferred resins include, for example, epoxy resins, phenolic resins, polyimide resins, silicone resins, polyamide resins, and liquid crystal polymers. Preferred fillers include, for example, insulating oxide particles such as silica particles, alumina particles, titania particles, and zirconia particles. The maximum diameter of the fillers is preferably, for example, 30 μm or more and 40 μm or less. For example, a material containing silica particles in a solid epoxy resin is more preferable.
[0107] The release sheet 550 is preferably a heat-activated release sheet. Being a heat-activated release sheet makes it possible to peel off the release sheet 550 more efficiently when heated and pressurized.
[0108] The support 560 is made of glass epoxy resin or the like. Preferably, the support 560 is a thermosetting resin.
[0109] 1, 1A...Solid electrolytic capacitor 10...Capacitor element 10E1...First end 10E2...Second end 11...Anode electrode 12...Dielectric layer 13...CP layer 14...Dam for CP 19C, 19L...Through-hole for anode 20...Cathode electrode 20E1...First end 20E2...Second end 29C, 29L...Through-hole for cathode 50, 51, 52...Insulating resin 61, 62...External electrodes 100...Capacitor element laminate 101...Top surface 102...Bottom surface 110...First sheet laminate 120...Second sheet laminate 550...Release sheet 560...Support 131...Inner layer CP 132...Outer layer CP E21, S11, S21...Cutting lines
Claims
1. Capacitor element formation step of sequentially forming a dielectric layer and a solid electrolyte layer on the surface of a flat film-shaped anode electrode foil to form a plurality of flat film-shaped capacitor elements; anode through-hole formation step of forming an anode through-hole that penetrates the plurality of flat film-shaped capacitor elements in the thickness direction; cathode through-hole formation step of forming a cathode through-hole that penetrates the flat film-shaped cathode electrode foil in the thickness direction; first sheet laminate formation step of alternately stacking the plurality of flat film-shaped capacitor elements and the flat film-shaped cathode electrode foil with the solid electrolyte layer in between to form a first sheet laminate having a top surface and a bottom surface facing the top surface; first sealing step of sealing the top surface of the first sheet laminate with a first resin and filling the anode through-hole and the cathode through-hole with the first resin; second sheet laminate formation step of cutting the first sheet laminate along a first cutting line perpendicular to the top surface and the bottom surface to form a plurality of second sheet laminates. A method for manufacturing a solid electrolytic capacitor, comprising: an arrangement step of arranging a plurality of second sheet laminates on a release sheet; a second sealing step of covering the entire top surface and the side surface along the first cutting line of the plurality of second sheet laminates, on which the first resin is formed, with an insulating second resin; and a fragmentation step of cutting the plurality of second sheet laminates, which are sealed with the first and second resins while arranged on the release sheet, along a second cutting line and a third cutting line perpendicular to the second cutting line, to form fragmented capacitor laminates.
2. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the capacitor laminate has a top surface, a bottom surface opposite to the top surface, and a side surface connected to the top surface and the bottom surface, and the interface between the first resin and the second resin is not exposed on the side surface but is exposed on the bottom surface.
3. The method for manufacturing a solid electrolytic capacitor according to claim 1 or claim 2, wherein the second sheet laminate is formed by cutting the first sheet laminate into strips along the first cutting line.
4. The method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 3, wherein the second sheet laminate is formed at predetermined intervals.
5. The method for manufacturing a solid electrolytic capacitor according to claim 4, wherein the second sheet laminate is arranged at equal intervals.
6. A method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 5, wherein the first resin and the second resin are made of the same component.
7. A method for manufacturing a solid electrolytic capacitor according to any one of claims 1 to 5, wherein the first resin and the second resin are made of different components.
8. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the release sheet has the property of being easily peeled off when heat is applied.
9. A solid electrolytic capacitor comprising: a plurality of flat film capacitor elements having a dielectric layer and a solid electrolyte layer on the surface of a flat film anode electrode foil, and a flat film cathode electrode foil, which are alternately stacked with the solid electrolyte layer in between, and having a top surface, a bottom surface opposite to the top surface, and sides connected to the top surface and the bottom surface; a first resin covering the top surface and the bottom surface of the capacitor laminate; and a second resin covering the first resin formed on the top surface and the sides, wherein the plurality of flat film capacitor elements have through-holes for anodes that penetrate in the thickness direction, and the flat film cathode electrode foil has through-holes for cathodes that penetrate in the thickness direction, and the first resin is filled in the through-holes for anodes and cathodes.
10. The solid electrolytic capacitor according to claim 9, wherein the interface between the first resin and the second resin is exposed on the bottom surface.
11. The solid electrolytic capacitor according to claim 9 or claim 10, wherein the first resin and the second resin are made of the same components.
12. The solid electrolytic capacitor according to claim 9 or claim 10, wherein the first resin and the second resin are made of different components.