Solid electrolytic capacitor
By enhancing the contact area between the lead frame and anode bodies through laser-irradiated openings, the capacitor achieves lower ESR, addressing the challenge of insufficient adhesion in existing designs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
- Filing Date
- 2025-12-11
- Publication Date
- 2026-06-25
AI Technical Summary
Existing solid electrolytic capacitors face challenges in achieving a low equivalent series resistance (ESR) due to insufficient contact area and adhesion between the lead frame and anode bodies.
The design incorporates a lead frame with recessed openings at its ends, which are laser-irradiated to form joints with the anode bodies, increasing the contact area and adhesion, thereby reducing ESR.
This configuration enhances adhesion and reduces ESR by improving the electrical connection between the lead frame and anode bodies, resulting in a more efficient capacitor performance.
Smart Images
Figure JP2025043251_25062026_PF_FP_ABST
Abstract
Description
Solid electrolytic capacitor
[0001] The present disclosure relates to a solid electrolytic capacitor. More specifically, the present disclosure relates to a solid electrolytic capacitor provided with capacitor elements.
[0002] Patent Document 1 describes a solid electrolytic capacitor. This solid electrolytic capacitor includes a plurality of capacitor elements, an anode lead terminal, and three or more joints. Each of the plurality of capacitor elements has an anode portion and a cathode portion and is laminated with each other. The anode lead terminal is electrically connected to at least one of the anode portions. The three or more joints join and electrically connect the laminated anode portions. The laminated anode portions have a first surface and a second surface disposed on the outermost sides in one and the other directions of the lamination direction. The three or more joints include a first joint having a first area on the first surface and a second joint having a second area smaller than the first area on the first surface.
[0003] International Publication No. 2023 / 026811
[0004] In the solid electrolytic capacitor described in Patent Document 1, a low ESR one is desired.
[0005] An object of the present disclosure is to provide a solid electrolytic capacitor capable of achieving a lower ESR.
[0006] A solid electrolytic capacitor according to one aspect of the present disclosure includes a capacitor element including an anode body, a collective anode portion in which anode bodies of a plurality of the capacitor elements are laminated, and a lead frame that caulks the collective anode portion. The lead frame has a first end portion and a second end portion. Also, the lead frame has the first end portion and the second end portion disposed on one surface of the collective anode portion in the lamination direction of the plurality of anode bodies. The first end portion and the second end portion have three or more openings recessed in the lamination direction. At least one of the three or more openings is formed across the first end portion and the second end portion.
[0007] Figure 1 is a cross-sectional view showing a solid electrolytic capacitor according to this embodiment. Figure 2 is a cross-sectional view showing the lead frame of the aggregate anode portion of the solid electrolytic capacitor according to this embodiment. Figure 3 is a plan view showing the lead frame of the aggregate anode portion of the solid electrolytic capacitor according to this embodiment. Figure 4 is a plan view showing a modified example of the lead frame used in the solid electrolytic capacitor according to this embodiment. Figure 5 is a plan view showing a modified example of the lead frame used in the solid electrolytic capacitor according to this embodiment. Figure 6 is a plan view showing a modified example of the lead frame used in the solid electrolytic capacitor according to this embodiment. Figure 7 is a plan view showing the lead frame of the aggregate anode portion of the solid electrolytic capacitor according to this embodiment. Figure 8 is a plan view showing the lead frame of the aggregate anode portion of the solid electrolytic capacitor according to this embodiment. Figure 9 is a plan view showing a simulation analysis model of the solid electrolytic capacitor according to this embodiment. Figure 10 is a plan view showing a simulation analysis model of a comparative example. Figure 11 is a plan view showing a simulation analysis model of a reference example. Figure 12 is a cross-sectional view showing a simulation analysis method of ESR. Figure 13 is a graph showing the simulation results. Figure 14 is a graph showing the simulation results.
[0008] The solid electrolytic capacitors according to the embodiments will be described below with reference to the drawings. The figures described in the embodiments below are schematic diagrams, and the ratios of the size and thickness of each component do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the embodiments below are merely examples of this disclosure. This disclosure is not limited to the embodiments below, and various modifications are possible depending on the design, etc., as long as the effects of this disclosure can be achieved. In this disclosure, terms indicating directions such as "front," "back," "up," "down," "left," and "right" are used only to describe the embodiments, and these terms do not limit the usage conditions of the solid electrolytic capacitor.
[0009] (Embodiment) 1. Overview The solid electrolytic capacitor 100 according to this embodiment comprises a capacitor element 1, a cluster anode section 2, and a lead frame 3, as shown in Figures 1, 2, and 3. The capacitor element 1 includes an anode body 11. The cluster anode section 2 is formed by stacking the anode bodies 11 of a plurality of capacitor elements 1. The lead frame 3 crimps (clinches) the cluster anode section 2. The lead frame 3 has a first end 31 and a second end 32. The first end 31 and the second end 32 are arranged on one side 21 of the cluster anode section 2 in the stacking direction of the plurality of anode bodies 11. The first end 31 and the second end 32 have three or more openings 4 that are recessed in the stacking direction. At least one of the three or more openings 4 is formed across the first end 31 and the second end 32.
[0010] According to this embodiment, the joint portion 7 formed at the position of the opening 4 is joined to both the lead frame 3 and the anode 11, increasing the contact area between the lead frame 3 and the anode 11. As a result, the adhesion between the lead frame 3 and the anode 11 is improved, and ESR can be reduced.
[0011] 2. Details <Capacitor element> The capacitor element 1 comprises an anode 11 and a cathode 12. The cathode 12 is formed on the surface of the anode 11 via an insulating layer.
[0012] The anode body 11 constitutes the anode of the capacitor element 1. The anode body 11 is composed of a metal foil formed of a valve metal or a porous sintered body formed of a valve metal. Examples of valve metals include, but are not limited to, aluminum, tantalum, niobium, and titanium.
[0013] One end (front end) of the anode body 11 is configured as a laminated portion 111. Multiple laminated portions 111 are stacked in the vertical direction to form a composite anode portion 2.
[0014] The insulating layer (etched layer) is preferably formed over the entire surface of the anode 11, but it is sufficient if it is formed at least between the anode 11 and the cathode 12. The insulating layer is made of an electrically insulating dielectric or the like. The insulating layer can be formed from an oxide formed on the surface of the anode 11 by a vapor phase method such as oxidation or vapor deposition, and if the anode 11 is made of aluminum, the insulating layer may be made of aluminum oxide.
[0015] The cathode body 12 constitutes the cathode of the capacitor element 1. The cathode body 12 has a solid electrolyte layer. The cathode body 12 may also have a carbon layer and a silver layer. The cathode body 12 is provided on approximately the rear half in the front-to-back direction of the capacitor element 1. The cathode body 12 is also arranged to cover the upper surface, lower surface, and rear end surface (the end surface opposite to the laminated portion 111) of the anode body 11.
[0016] The solid electrolyte layer is formed in layers containing conductive polymers and inorganic solid electrolytes. Examples of conductive polymers include polypyrrole, polythiophene, and polyaniline. The thickness of the solid electrolyte layer is set according to the required voltage resistance.
[0017] The carbon layer is provided on the solid electrolyte layer. The carbon layer is formed in layers containing carbon particles. The carbon layer can be formed by applying carbon paste or the like onto the solid electrolyte layer and curing it. The thickness of the carbon layer is set according to the required conductivity performance.
[0018] The silver layer is provided on top of the carbon layer. The silver layer is formed in layers containing silver particles. The silver layer can be formed by applying silver paste or the like onto the carbon layer and hardening it. The thickness of the silver layer is set according to the required conductivity performance.
[0019] A resist layer 14 is provided on the capacitor element 1. The resist layer 14 is formed from a cured resin insulating material or the like. The resist layer can also be formed from a resist material such as a water-repellent ink for inkjet printing. Alternatively, the resist layer can be formed from a resist material such as an insulating tape.
[0020] The resist layer 14 is provided on the insulating layer on the surface of the anode 11. The resist layer 14 is also provided on the front side of the cathode 12, but in a position that does not cover the surface of the laminated portion 111 of the anode 11. The resist layer 14 is also positioned on the upper and lower sides of the anode 11.
[0021] <Anode Cluster> Multiple capacitor elements 1 are stacked in the vertical direction. The upper and lower surfaces of the multiple capacitor elements 1 that are opposite each other in the vertical direction are bonded together by an adhesive layer 13. The adhesive layer 13 can be formed from a cured product of a conductive adhesive such as silver paste. The adhesive layer 13 bonds the cathode body 12 on the lower surface of the upper capacitor element 1 to the cathode body 12 on the upper surface of the lower capacitor element 1 of the vertically adjacent capacitor elements 1.
[0022] The aggregate anode section 2 is formed by stacking multiple capacitor elements 111 in the vertical direction. The aggregate anode section 2 is formed by crimping the stacked multiple stacked sections 111 together. A joint section 7 is also formed in the aggregate anode section 2. The joint section 7 is formed to penetrate the aggregate anode section 2 in the vertical direction. The joint section 7 is electrically connected to the anode body 11 at the location of the stacked section 111. Therefore, the multiple anode bodies 11 are electrically connected by the joint section 7.
[0023] <Lead Frame> The lead frame 3 is a component used to crimp the aggregate anode section 2 with multiple stacked sections 111. The lead frame 3 is also used as an external terminal for the solid electrolytic capacitor 100.
[0024] The lead frame 3 is a conductive metal component, which can be made of, for example, copper. The lead frame 3 can be obtained by forming a metal plate through processes such as bending.
[0025] The lead frame 3 is equipped with an anode lead terminal 3A and a cathode lead terminal 3B. The anode lead terminal 3A is located at the front of the solid electrolytic capacitor 100. The cathode lead terminal 3B is located at the rear of the solid electrolytic capacitor 100.
[0026] The anode lead terminal 3A has an anode terminal portion 37 located outside the outer resin casing 5. The anode terminal portion 37 is formed in a substantially L-shape in cross-section so as to be located on the front and bottom sides of the outer resin casing 5. The anode lead terminal 3A also includes a first end portion 31, a second end portion, a contact portion 33, and a pair of connecting portions 35. The first end portion 31, the second end portion 32, the contact portion 33, and the pair of connecting portions 35 are located inside the outer resin casing 5.
[0027] The contact portion 33 protrudes rearward from the upper end of the anode terminal portion 37 and is located inside the outer resin 5 (see Figure 1). The rear end of the contact portion 33 is formed in a flat plate shape, and the first end portion 31 and the second end portion 32 are located above it (see Figure 2). In a plan view (viewed from above), the first end portion 31 and the second end portion 32 are formed in a rectangular flat plate shape and are located opposite the contact portion 33 in the vertical direction.
[0028] The pair of connecting portions 35 connect the first end portion 31 and the second end portion 32 to the contact portion 33. One of the pair of connecting portions 35 connects the left end of the first end portion 31 to the left end of the contact portion 33. The other of the pair of connecting portions 35 connects the right end of the second end portion 32 to the right end of the contact portion 33 (see Figure 2). When viewed from the front, each of the pair of connecting portions 35 is formed in an arc shape, such as a semicircle (see Figure 2).
[0029] The cathode lead terminal 3B has a cathode terminal portion 38 located outside the outer resin casing 5. The cathode terminal portion 38 is formed in a substantially L-shape in cross-section so as to be located on the rear and lower sides of the outer resin casing 5. The cathode lead terminal 3B also includes an element support portion 39. The element support portion 39 is located inside the outer resin casing 5.
[0030] <Solid Electrolytic Capacitor> The solid electrolytic capacitor 100 of this embodiment comprises a plurality of capacitor elements 1, a lead frame 3, and an outer resin 5.
[0031] As described above, the multiple capacitor elements 1 are stacked vertically with approximately half of their rear portions connected via an adhesive layer 13. Furthermore, the approximately half of the rear portions of the multiple capacitor elements 1 are placed on the element support portion 39 of the cathode lead terminal 3B via the adhesive layer 13 while in this stacked state. The cathode bodies 12 of the multiple capacitor elements 1 are electrically connected to the cathode lead terminal 3B by the conductive adhesive layer 13.
[0032] Furthermore, the multiple capacitor elements 1 have their front end stacked portions 111 stacked vertically, and a combined anode portion 2 is formed from the stacked multiple stacked portions 111. The combined anode portion 2 is placed on the contact portion 33 of the anode lead terminal 3A. The first end portion 31 and the second end portion 32 of the anode lead terminal 3A are placed on the upper surface of the combined anode portion 2. That is, the first end portion 31 and the second end portion 32 are positioned in contact with one side (the upper surface, which is the first side) 21 of the combined anode portion 2 in the stacking direction of the multiple anode bodies 11. The contact portion 33 is positioned in contact with the side (the lower surface, which is the second side) 22 opposite to the side 21 of the combined anode portion 2 on which the first end portion 31 and the second end portion 32 are placed.
[0033] The aggregate anode section 2 is crimped by the anode lead terminals 3A. That is, the aggregate anode section 2 is clamped in the vertical direction between the first end 31, the second end 32 and the contact portion 33. As a result, the multiple laminated sections 111 constituting the aggregate anode section 2 are tightly packed together and integrated.
[0034] The first end 31 and the second end 32 are arranged facing each other in the left-right direction on one side (first side) 21 of the anode aggregate 2. Here, the left-right direction is perpendicular to the stacking direction (up-down direction) of the multiple stacked sections 111 and the front-back direction (the direction in which the anode lead terminals 3A and cathode lead terminals 3B are aligned). The first end 31 and the second end 32 are each arranged to extend in the left-right direction. The tip surface of the first end 31 and the tip surface of the second end 32 face each other, and a gap 34 is formed between the tip surface of the first end 31 and the tip surface of the second end 32. In a plan view (viewed from above), the gap 34 is formed at a position corresponding to approximately the center of the anode aggregate 2 in the left-right direction. Therefore, approximately the center of the anode aggregate 2 in the left-right direction is exposed at the position of the gap 34.
[0035] In this embodiment, the solid electrolytic capacitor 100 has three openings 4 at the first end 31 and the second end 32. The three openings 4 include a first opening 41 formed at the first end 31, a second opening 42 formed at the second end 32, and a third opening 43 formed across the first end 31 and the second end 32.
[0036] The three openings 4 are recessed in the stacking direction of the multiple stacked portions 111 in the aggregate anode portion 2. Specifically, the first opening 41 is recessed downward from the upper surface of the first end portion 31. The second opening 42 is recessed downward from the upper surface of the second end portion 32. The third opening 43 is recessed downward from the upper surfaces of the first end portion 31 and the second end portion 32, and from the upper surface of the aggregate anode portion 2 in the gap 34.
[0037] The opening 4 is formed by irradiating the first end portion 31, the second end portion 32, and the gap 34 with a laser. In this embodiment, the opening 4 can be formed by irradiating the laser from only one side of the stacking direction of the multiple stacked portions 111. That is, in this embodiment, the laser is irradiated from above in the vertical direction, which is the stacking direction of the multiple stacked portions 111, to the first end portion 31, the second end portion 32, and the gap 34. As a result, the laser irradiation device can be provided only on one side (above) of the first end portion 31, the second end portion 32, and the gap 34, simplifying the laser irradiation device and improving the efficiency of the opening 4 formation process.
[0038] In this embodiment, a joint 7 is formed at a position corresponding to the opening 4. The joint 7 is formed when a portion of the metal of the laminated portion 111, which has been melted by laser irradiation, hardens. That is, when a laser is irradiated from above onto the first end 31, the second end 32, and the gap 34, the opening 4 (first opening 41, second opening 42, and third opening 43) is formed, and the laser then penetrates the aggregate anode portion 2 vertically to reach the lower contact portion 33. As a result, the metal of the multiple laminated portions 111 of the aggregate anode portion 2 is thermally melted at the laser irradiation position, and through holes are formed that penetrate the aggregate anode portion 2 vertically, corresponding to the position of the opening 4.
[0039] After this, when the laser irradiation is stopped, the molten metal of the laminated portion 111 cools and hardens, adhering to the entire inner wall of the opening 4 and the through hole. In this way, joint portions 7 are formed at positions corresponding to the opening 4, penetrating the aggregate anode portion 2 in the stacking direction (vertical direction) of the multiple laminated portions 111. The joint portions 7 are formed corresponding to each opening 4. That is, the first joint portion 71 is formed at the first opening 41, the second joint portion 72 is formed at the second opening 42, and the third joint portion 73 is formed at the third opening 43. The anode bodies 11 of the multiple capacitor elements 1 are then electrically connected by the joint portions 7. Furthermore, since the joint portions 7 are formed to reach the contact portion 33, the anode bodies 11 of the multiple capacitor elements 1 are electrically connected to the anode lead terminal 3A.
[0040] The joint portion 7 is formed in a nearly cylindrical shape, but it may also be formed in a shape where the diameter gradually decreases from the end on the side where the laser is irradiated to the opposite end. In this embodiment, the joint portion 7 is formed so that the diameter gradually decreases from the upper end (opening 4 side) to the lower end (contact portion 33 side). This is because the laser irradiation energy gradually decreases from top to bottom, so less metal is melted by the laser irradiation.
[0041] In some cases, the entire through-hole formed by laser irradiation may be filled with the joint 7, but usually, a void is formed within the through-hole where the joint 7 is not present in some areas. Also, while the entire opening 4 is often sealed with the joint 7, in other cases only a portion of the opening 4 may be sealed with the joint 7.
[0042] In this embodiment, the opening 4 is circular when viewed from the stacking direction (above). In this case, the molten metal from the anode body 11 melted by laser irradiation adheres more uniformly to the opening 4, making it easier to achieve a lower ESR.
[0043] After forming the joint 7 as described above, the outer resin 5 is formed. The outer resin 5 is formed to cover the entirety of the multiple capacitor elements 1, including the aggregate anode portion 2. The outer resin 5 is also formed to cover the contact portion 33 and the element support portion 39. Therefore, the anode terminal portion 37 and the cathode terminal portion 38 are located outside the outer resin 5. The outer resin 5 is made of a thermosetting resin such as epoxy resin. The outer resin 5 is formed by molding methods such as injection molding, transfer molding, and casting.
[0044] In this embodiment, the side surface portion 23 of the collective anode portion 2 and the connecting portion 35 of the lead frame 3 face each other with a gap 36 therebetween, and a part of the exterior resin 5 is filled in this gap 36. The side surface portion 23 is formed to extend in a direction intersecting with the one surface (upper surface) 21 of the collective anode portion 2 where the first end portion 31 and the second end portion 32 are arranged. The connecting portion 35 is formed between the first end portion 31 and the second end portion 32 of the anode lead terminal 3A and the contact portion 33. Then, when forming the exterior resin 5, the exterior resin 5 can be introduced into the gap 36 to absorb stress at the connecting portion 35, and displacement of the first end portion 31 and the second end portion 32 on the one surface 21 and breakage of the joint portion 7 can be suppressed.
[0045] In this embodiment, the connecting portion 35 is formed in an arc shape when viewed from the front. In this case, stress can be absorbed at the connecting portion 35, and breakage of the first end portion 31 and the second end portion 32 and the joint portion 7 on the one surface 21 can be more suppressed.
[0046] And in the solid electrolytic capacitor 100 of this embodiment, the first end portion 31 and the second end portion 32 have three or more opening portions 4, and at least one of the three or more opening portions 4 is formed across the first end portion 31 and the second end portion 32. Therefore, the contact area between the lead frame 3 and the anode body 11 that is melted by laser irradiation increases, and improvement in adhesion and reduction in ESR can be achieved.
[0047] (Modification) The embodiment is merely one of various embodiments of the present disclosure. The embodiment can be variously modified according to design and the like as long as the object of the present disclosure can be achieved.
[0048] In the embodiment, the case where three opening portions 4 and the joint portion 7 are formed has been described, but not limited thereto. The number of the opening portions 4 may be four, may be five, or may be six or more.
[0049] In the embodiment, the case where one opening portion 4 is formed across the first end portion 31 and the second end portion 32 has been described, but not limited thereto. Two or more opening portions 4 may be formed across the first end portion 31 and the second end portion 32.
[0050] In this embodiment, a case in which a gap 34 is provided between the first end portion 31 and the second end portion 32 has been described, but the invention is not limited to this case, and a gap 34 may not be provided. In this case, the tip surface of the first end portion 31 and the tip surface of the second end portion 32 are in contact.
[0051] Figure 4 shows the aggregate anode portion 2, the first end portion 31, and the second end portion 32 before laser irradiation in an embodiment. In this embodiment, no openings 4 are formed in the first end portion 31 and the second end portion 32 before laser irradiation, and the openings 4 are formed by laser irradiation.
[0052] On the other hand, in the modified examples shown in Figures 5 and 6, the first end portion 31 and the second end portion 32 have notches 61 and 62 in advance before laser irradiation. The notches 61 and 62 are formed in a semicircular shape in plan view. The notch 61 opens on both the upper and lower surfaces and the tip surface of the first end portion 31. The notch 61 opens on both the upper and lower surfaces and the tip surface of the second end portion 32.
[0053] In Figure 5, the tip of the first end 31 and the tip of the second end 32 are in contact without any gap, and the notches 61 and 62 come together to form a circular opening. In Figure 6, a gap 34 is formed between the tip of the first end 31 and the tip of the second end 32, and the notches 61 and 62 are positioned opposite each other in the left-right direction.
[0054] In this way, by forming notches 61 and 62 in the first end 31 and the second end 32 in advance before laser irradiation, the laser can more easily irradiate the aggregate anode portion 2 through the notches 61 and 62, making it easier to efficiently form the opening 4 in the aggregate anode portion 2. In Figures 5 and 6, notches 61 and 62 are formed at the positions where the third opening 43 is formed, but the method is not limited to this, and holes may be formed in advance at the positions where the first opening 41 and the second opening 42 are formed.
[0055] In the embodiment, the opening 4 was formed in a circular shape when viewed from above, but it is not limited to this. For example, as shown in Figure 7, the opening 4 may be formed in a regular hexagon shape when viewed from above, or as shown in Figure 8, the opening 4 may be formed in a square shape when viewed from above. The shape of the opening 4 can be changed depending on the laser irradiation conditions. The shape of the joint 7 may also be changed according to the shape of the opening 4, but in most cases the shape of the joint 7 is approximately circular when viewed from above. In particular, if the diameter of the opening 4 is small, the shape of the joint 7 is circular when viewed from above.
[0056] (Simulation) In the following, the ESR was calculated by simulation. Figure 9 shows the analysis model (example) corresponding to the solid electrolytic capacitor of this embodiment. Figure 10 shows the analysis model of a comparative example, and Figure 11 shows the analysis model of a reference example.
[0057] As shown in Figure 12, the solid electrolytic capacitor used in the simulation has a cylindrical junction 7. That is, while the actual junction 7 is formed to taper towards the end, in the simulation it is formed as a straight cylinder in the vertical direction. The junction 7 is attached to the inner wall of the through hole that penetrates the opening 4 and the aggregate anode portion 2.
[0058] The top-down shape of the opening 4 is circular. The outer diameter of the opening 4 in the examples and comparative examples was 0.35 mm, and the outer diameter of the opening 4 in the reference example was 0.45 mm. The thickness of the joint 7 was also changed based on the assumed loss of metal (Al) from the laminated portion 111 due to laser irradiation. In Example 1, Comparative Example 1, and Reference Example 1, assuming a small amount of metal loss, the thickness of the joint 7 was set to R1=R2=45 μm and R3=58 μm. In Example 2, Comparative Example 2, and Reference Example 2, assuming a moderate amount of metal loss, the thickness of the joint 7 was set to R1=R2=R3=25 μm. In Example 3, Comparative Example 3, and Reference Example 3, assuming a large amount of metal loss, the thickness of the joint 7 was set to R1=R2=R3=10 μm.
[0059] Then, the resistance ratios between C1 and t1 to t5 were calculated. The results are shown in Figure 13. In all of the analysis models for the examples, comparative examples, and reference examples, the resistance value between C1 and t5 was the smallest. Between C1 and t1, the length of the joint 7 is the longest in all of the analysis models for the examples, comparative examples, and reference examples. However, in Examples 1 to 3, the third joint 73 is electrically connected to both the first end 31 and the second end of the copper lead frame 3, which has lower electrical resistance than Al, at the third opening 43. Therefore, the resistance value between C1 and t1 in Examples 1 to 3 was lower than in Comparative Examples 1 to 3 and Reference Examples 1 to 3.
[0060] Figure 14 shows the change in the resistance ratio with respect to the Al thickness ratio for each of Examples 1-3 (■), Comparative Examples 1-3 (▲), and Reference Examples 1-3 (○). The change in the resistance ratio with respect to the Al thickness ratio is smaller for Examples 1-3 than for Comparative Examples 1-3 and Reference Examples 1-3. Therefore, in this embodiment, a reduction in ESR variation caused by variations in the thickness of the joint 7 (variations in Al loss) can also be expected.
[0061] (Summary) As described above, the solid electrolytic capacitor (100) according to the first embodiment comprises a capacitor element (1), a aggregate anode section (2), and a lead frame (3). The capacitor element (1) includes an anode body (11). The aggregate anode section (2) is formed by stacking the anode bodies (11) of a plurality of capacitor elements (1). The lead frame (3) crimps the aggregate anode section (2). The lead frame (3) has a first end (31) and a second end (32). The first end (31) and the second end (32) are arranged on one side (21) of the aggregate anode section (2) in the stacking direction of the plurality of anode bodies (11). The first end (31) and the second end (32) have three or more openings (4) that are recessed in the stacking direction. At least one of the three or more openings (4) is formed extending from the first end (31) to the second end (32).
[0062] According to this embodiment, the contact area between the lead frame (3) and the anode body (11) that is melted by laser irradiation is increased, thereby improving adhesion and reducing ESR.
[0063] The second embodiment is a solid electrolytic capacitor (100) according to the first embodiment, wherein the lead frame (3) has a contact portion (33) that contacts one side (21) and the other side (22) opposite to the anode aggregate portion (2) on which the first end portion (31) and the second end portion (32) are arranged.
[0064] According to this embodiment, the aggregate anode portion (2) can be firmly crimped between the first end portion (31) and the second end portion (32) and the contact portion (33).
[0065] The third embodiment is a solid electrolytic capacitor (100) according to the first or second embodiment, wherein the first end (31) and the second end (32) are arranged opposite each other in a direction perpendicular to the stacking direction. A gap (34) is formed between the first end (31) and the second end (32).
[0066] According to this embodiment, the contact area between the lead frame (3) and the anode body (11) that is melted by laser irradiation is increased, which improves adhesion and enables low ESR.
[0067] The fourth embodiment is a solid electrolytic capacitor (100) according to any one of the first to third embodiments, wherein three or more openings (4) each penetrate the first end (31) and the second end (32) in the stacking direction.
[0068] According to this embodiment, it becomes easier to irradiate the aggregate anode portion (2) with a laser through the opening (4), and the anode body (11) can be melted with less energy.
[0069] The fifth embodiment is a solid electrolytic capacitor (100) according to any one of the first to fourth embodiments, wherein three or more openings (4) are circular when viewed from the stacking direction.
[0070] According to this embodiment, the molten metal from the anode body (11) melted by laser irradiation is more likely to adhere uniformly to the opening (4), making it easier to achieve a lower ESR.
[0071] The sixth embodiment is a solid electrolytic capacitor (100) according to any one of the second to fifth embodiments, wherein the aggregate anode portion (2) has a side portion (23) that extends in a direction intersecting the one side (21) on which the first end portion (31) and the second end portion (32) are arranged. The lead frame (3) has a connecting portion (35) between the first end portion (31) and the second end portion (32) and the contact portion (33). The connecting portion (35) faces the side portion (23) via a gap (36). The gap (36) is filled with an exterior resin (5).
[0072] According to this embodiment, when forming the exterior resin (5), the exterior resin (5) can be introduced into the gap (36) to absorb stress at the connecting portion (35) of the lead frame (3), thereby suppressing misalignment of the lead frame (3) on one side (21) and damage to the joint (7).
[0073] The seventh embodiment is a solid electrolytic capacitor (100) according to the sixth embodiment, wherein the connecting portion (35) is formed in an arc shape.
[0074] According to this embodiment, when forming the outer resin (5), the outer resin (5) can be introduced into the gap (36) to better absorb stress at the connecting portion (35) of the lead frame (3), thereby further suppressing misalignment of the lead frame (3) on one side (21) and damage to the joint (7).
[0075] 1 Capacitor element 2 Anode assembly 3 Lead frame 4 Opening 5 Outer resin 11 Anode body 21 First side 22 Second side 23 Side 31 First end 32 Second end 33 Contact part 34 Gap 35 Connecting part 36 Gap 100 Solid electrolytic capacitor
Claims
1. A solid electrolytic capacitor comprising: a capacitor element including an anode; a composite anode portion formed by stacking a plurality of anodes of the capacitor elements; and a lead frame for crimping the composite anode portion, wherein the lead frame has a first end and a second end, the first end and the second end are arranged on one side of the composite anode portion in the stacking direction of the plurality of anodes, the first end and the second end have three or more openings recessed in the stacking direction, and at least one of the three or more openings is formed extending from the first end to the second end.
2. The solid electrolytic capacitor according to claim 1, wherein the lead frame has a contact portion that contacts one side of the aggregate anode portion opposite to the one side on which the first end and the second end are arranged.
3. The solid electrolytic capacitor according to claim 1 or 2, wherein the first end and the second end are arranged opposite each other in a direction perpendicular to the stacking direction, and a gap is formed between the first end and the second end.
4. The solid electrolytic capacitor according to any one of claims 1 to 3, wherein each of the three or more openings penetrates the first end and the second end in the stacking direction.
5. The solid electrolytic capacitor according to any one of claims 1 to 4, wherein each of the three or more openings is circular when viewed from the stacking direction.
6. The solid electrolytic capacitor according to any one of claims 2 to 5, wherein the aggregate anode portion has a side portion extending in a direction intersecting the one side on which the first end and the second end are arranged, the lead frame has a connecting portion between the first end and the second end and the contact portion, the connecting portion faces the side portion with a gap in between, and the gap is filled with exterior resin.
7. The connecting portion is formed in an arc shape, as described in claim 6.