Solid Electrolytic Capacitors

Abstract

To provide a solid electrolytic capacitor that can improve the manufacturing yield while achieving miniaturization and thinning.SOLUTION: A solid electrolytic capacitor 1 according to an embodiment of the present invention includes a tantalum lead-out wire 11 and a capacitor element 10. The capacitor element 10 includes an anode body 12, a dielectric layer 13, a solid electrolyte layer 14, and a cathode body 15. The tantalum lead-out wire 11 penetrates the capacitor element 10 in the penetration direction, a cross section perpendicular to the penetrating direction, of the tantalum lead-out wire 11 and the capacitor element 10 has a rectangular shape with the longitudinal direction extending in the horizontal direction, and Wc / Wd is less than 0.5, when Wc is the length in the vertical direction of the cross section perpendicular to the penetration direction of the tantalum lead-out wire 11, and Wd is the length in the vertical direction of the cross section perpendicular to the through direction of the capacitor element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a solid electrolytic capacitor. [Background technology]

[0002] In recent years, solid electrolytic capacitors have been widely used in various fields such as electronic devices. Patent Document 1 discloses a technology related to a noise filter including a thin tantalum wire, a capacitance forming portion provided around the thin tantalum wire, and a conductive layer provided around the capacitance forming portion. The noise filter (solid electrolytic capacitor) disclosed in Patent Document 1 has a three-terminal structure in which the thin tantalum wire penetrates the capacitance forming portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-7105 A Summary of the Invention [Problem to be solved by the invention]

[0004] Due to the miniaturization of electronic devices in recent years, there is a demand for smaller and thinner solid electrolytic capacitors as well. The noise filter (solid electrolytic capacitor) disclosed in Patent Document 1 has a cylindrical structure of tantalum thin wires (i.e., the cross-sectional shape is circular), making it difficult to realize a smaller and thinner size.

[0005] On the other hand, by making the tantalum lead-in wire flat (with a rectangular cross-sectional shape), it is possible to realize a smaller and thinner solid electrolytic capacitor. However, when the cross section of the tantalum lead-in wire is made rectangular, the manufacturing yield may decrease unless the relationship in size between the tantalum lead-in wire and the capacitor element is appropriately set.

[0006] In view of the above problems, an object of the present invention is to provide a solid electrolytic capacitor that can be made smaller and thinner while improving the manufacturing yield. [Means for solving the problem]

[0007] A solid electrolytic capacitor according to one embodiment of the present invention includes a tantalum lead-in wire and a capacitor element. The capacitor element includes an anode body made of a valve metal and covering a periphery of a central portion of the tantalum lead-in wire, a dielectric layer formed on the surface of the anode body, a solid electrolyte layer formed on the surface of the dielectric layer, and a cathode body formed on the surface of the solid electrolyte layer. The tantalum lead-in wire penetrates the capacitor element in a penetration direction, and a cross section of the tantalum lead-in wire and the capacitor element perpendicular to the penetration direction has a rectangular shape whose longitudinal direction extends horizontally, and Wc / Wd is less than 0.5, where Wc is the vertical length of the cross section perpendicular to the penetration direction of the tantalum lead-in wire and Wd is the vertical length of the cross section of the capacitor element perpendicular to the penetration direction. Effect of the Invention

[0008] According to the present invention, it is possible to provide a solid electrolytic capacitor that can be made smaller and thinner while improving the manufacturing yield. [Brief description of the drawings]

[0009] [Figure 1] 1 is a side view illustrating an example of a solid electrolytic capacitor according to an embodiment. [Diagram 2] FIG. 1 is a top view illustrating an example of a solid electrolytic capacitor according to an embodiment. [Diagram 3] 3 is a partial cross-sectional view of the center portion taken along line III-III in FIG. 1. [Figure 4] 4 is a cross-sectional view of a capacitor element portion taken along line IV-IV in FIG. 2. [Diagram 5] 1 is a table showing the relationship between Wc / Wd and the defect rate. [Figure 6]1 is a table showing the relationship between YA / PA and impedance at each frequency. [Figure 7] 1 is a table showing the relationship between Wa / Wb and impedance at each frequency. [Figure 8] FIG. 1 is a diagram for explaining the effect of the present invention. [Figure 9] FIG. 1 is a diagram for explaining the effect of the present invention. [Figure 10] FIG. 1 is a diagram for explaining the effect of the present invention. [Figure 11] 1 is a perspective view showing a configuration example of a solid electrolytic capacitor according to an embodiment; [Figure 12] 1 is a perspective view showing a configuration example of a solid electrolytic capacitor according to an embodiment; [Figure 13] 1 is a perspective view showing a configuration example of a solid electrolytic capacitor according to an embodiment; [Figure 14] 1 is a perspective view showing a configuration example of a solid electrolytic capacitor according to an embodiment; [Figure 15] 1 is a perspective view showing a configuration example of a solid electrolytic capacitor according to an embodiment; [Figure 16] FIG. 2 is a perspective view for explaining a manufacturing example of the solid electrolytic capacitor according to the embodiment. [Figure 17] FIG. 2 is a perspective view for explaining a manufacturing example of the solid electrolytic capacitor according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are a side view and a top view, respectively, showing an example of a solid electrolytic capacitor according to the present embodiment. As shown in Fig. 1 and Fig. 2, the solid electrolytic capacitor 1 according to the present embodiment includes a capacitor element 10 and tantalum lead-out wires 11a and 11b. In this specification, the tantalum lead-out wires 11a and 11b may be collectively referred to as tantalum lead-out wire 11. The same applies to other components (such as anode lead frames 20a and 20b).

[0011] The tantalum lead-through wire 11 penetrates the capacitor element 10 in the penetration direction (x-axis direction). Of the tantalum lead-through wire 11, the tantalum lead-through wires 11a and 11b exposed from the capacitor element 10 each constitute an anode lead-through wire. The tantalum lead-through wires (anode lead-through wires) 11a and 11b are connected to anode lead frames 20a and 20b, respectively.

[0012] Specifically, the anode lead frames 20a, 20b each include a pedestal portion 21a, 21b extending in the horizontal direction (x-axis direction) and an upright portion 23a, 23b standing upright from the pedestal portion 21a, 21b in the vertical direction (z-axis direction). The tantalum lead-wires (anode lead-wires) 11a, 11b are connected to the top surfaces of the upright portions 23a, 23b, respectively, to electrically connect the tantalum lead-wires (anode lead-wires) 11a, 11b to the anode lead frames 20a, 20b. For example, the tantalum lead-wires (anode lead-wires) 11a, 11b are connected to the upright portions 23a, 23b by welding. The pedestal portions 21a, 21b are connected to a substrate (not shown).

[0013] Cathode body 15 (see FIG. 3) of capacitor element 10 is electrically connected to cathode terminal 22 on the lower surface side (z-axis direction negative side) of capacitor element 10. For example, cathode body 15 is connected to cathode terminal 22 using a conductive adhesive. Cathode terminal 22 is connected to a substrate (not shown).

[0014] Thus, solid electrolytic capacitor 1 according to the present embodiment has a three-terminal structure in which tantalum leads 11a, 11b are connected to anode lead frames 20a, 20b at two locations, and cathode body 15 (see FIG. 3) is connected to cathode terminal 22 at one location.

[0015] Fig. 3 is a cross-sectional view for explaining the internal structure of capacitor element 10, and is a partial cross-sectional view of the center portion taken along line III-III in Fig. 1. As shown in Fig. 3, capacitor element 10 includes an anode body 12, a dielectric layer 13, a solid electrolyte layer 14, and a cathode body 15. A tantalum lead-out wire 11 is disposed in the center of capacitor element 10.

[0016] The tantalum lead-through wire 11 is made of metal tantalum (Ta). The tantalum lead-through wire 11 has a rectangular cross section in the yz plane (see FIG. 4), and can be formed, for example, by rolling a tantalum lead-through wire having a cylindrical structure.

[0017] Anode body 12 covers the periphery of the center of tantalum lead-through wire 11 (i.e., the portion other than tantalum lead-through wires 11a, 11b exposed from capacitor element 10). Anode body 12 can be formed using metallic tantalum (Ta), which is a valve metal. Tantalum lead-through wire 11 and anode body 12 may be formed integrally.

[0018] Dielectric layer 13 is formed on the surface of anode body 12. For example, dielectric layer 13 can be formed by anodizing the surface of anode body 12. For example, when tantalum is used for anode body 12, a tantalum oxide coating (dielectric layer 13) can be formed on the surface of anode body 12 by anodizing anode body 12. For example, the thickness of dielectric layer 13 can be appropriately adjusted by the voltage of anodization.

[0019] The solid electrolyte layer 14 is formed on the surface of the dielectric layer 13. For example, the solid electrolyte layer 14 can be formed using a conductive polymer. When forming the solid electrolyte layer 14, for example, chemical oxidation polymerization, electrolytic polymerization, or the like can be used. Alternatively, the solid electrolyte layer 14 may be formed by applying (impregnating) a conductive polymer solution and drying it.

[0020] The solid electrolyte layer 14 preferably contains a polymer made of a monomer containing at least one of pyrrole, thiophene, aniline, and derivatives thereof. In addition, it preferably contains a sulfonic acid compound as a dopant. In addition to the conductive polymer, the solid electrolyte layer 14 may contain oxide materials such as manganese dioxide and ruthenium oxide, and organic semiconductors such as TCNQ (7,7,8,8,-tetracyanoquinodimethane complex salt).

[0021] Cathode body 15 is formed on the surface of solid electrolyte layer 14. For example, cathode body 15 may be configured using a graphite layer formed on the surface of solid electrolyte layer 14 and a silver paste layer formed on the surface of the graphite layer. Cathode body 15 is connected to cathode terminal 22 on the lower surface side (z-axis direction negative side) of capacitor element 10 using a conductive adhesive.

[0022] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2, and is a diagram for explaining the cross-sectional shapes of capacitor element 10 and tantalum lead-in wire 11. Note that cathode terminal 22 is omitted from Fig. 4. In this embodiment, a cross section (yz plane) perpendicular to the penetration direction (x-axis direction) of tantalum lead-in wire 11 and capacitor element 10 has a rectangular shape with the longitudinal direction (y-axis direction) extending horizontally.

[0023] For example, the vertical length Wc of the cross section of tantalum lead-through wire 11 can be 0.05 mm or more and 0.6 mm or less, and the horizontal length Wa can be 0.2 mm or more and 3.3 mm or less. The vertical length Wd of the cross section of capacitor element 10 can be 0.3 mm or more and 1.2 mm or less, and the horizontal length Wb can be 1.0 mm or more and 4.1 mm or less.

[0024] In this case, in the solid electrolytic capacitor 1 according to the present embodiment, Wc / Wd is set to less than 0.5, preferably 0.3 or less, and more preferably 0.1 or more and 0.3 or less.

[0025] FIG. 5 is a table showing the relationship between Wc / Wd and the defect rate. FIG. 5 shows the wire insertion defect rate and pellet crack defect rate when Wc / Wd is 0.05, 0.1, 0.3, and 0.5, respectively. Here, a wire insertion defect is a wire deformation, a wire exposure from a capacitor element due to tilt, etc., and a pellet crack defect is a defect in which cracks occur in the pellet during pellet molding. The defect rate is the ratio (%) of the number of samples with defects to the total number of samples. The results shown in FIG. 5 are for a total of 1,000 samples.

[0026] As shown in Fig. 5, when Wc / Wd was 0.5, the wire insertion failure rate was 0% and the pellet crack failure rate was 0.3%. When Wc / Wd was 0.05, the wire insertion failure rate was 4.2% and the pellet crack failure rate was 0%. When Wc / Wd was 0.1 and 0.3, both the wire insertion failure rate and the pellet crack failure rate were 0%. Therefore, when Wc / Wd was less than 0.5, preferably 0.3 or less, and more preferably 0.1 to 0.3, the wire insertion failure rate and the pellet crack failure rate could be reduced.

[0027] In other words, when Wc / Wd is 0.5 or more, it is believed that the thickness of tantalum lead-in wire 11 becomes thicker relative to capacitor element (pellet) 10, which increases the number of cracks in the pellet. Also, when Wc / Wd is 0.05 or less, the thickness of tantalum lead-in wire 11 becomes thinner relative to capacitor element (pellet) 10, which is believed to cause wire insertion failure.

[0028] As described above, in the solid electrolytic capacitor according to the present embodiment, the tantalum lead-in wire has a flat shape (a rectangular cross-sectional shape). This allows the solid electrolytic capacitor to be made smaller and thinner. In addition, the size relationship between the tantalum lead-in wire and the capacitor element (specifically, the Wc / Wd relationship) is appropriately set, which allows the manufacturing yield to be improved. Therefore, the present invention can provide a solid electrolytic capacitor that can be made smaller and thinner while also allowing the manufacturing yield to be improved.

[0029] In the above-mentioned solid electrolytic capacitor, the cross-sectional shape of the tantalum lead-in wire 11 is rectangular, but in this embodiment, the cross-sectional shape of the tantalum lead-in wire 11 may be substantially rectangular or substantially flat, and may have, for example, R or C-surface fillets at the corners, or may have a track shape with curved ends. The values ​​of Wa and Wc can be found by measuring the maximum values ​​of the vertical and horizontal lengths, respectively.

[0030] In addition, in this embodiment, as shown in FIG. 4, if the perimeter of the cross section of tantalum lead-out wire 11 is YA (YA=(Wa+Wc)×2) and the perimeter of the cross section of capacitor element 10 is PA (PA=(Wb+Wd)×2), then YA / PA may be 0.1 or more and 0.9 or less, preferably 0.3 or more and 0.7 or less.

[0031] Figure 6 is a table showing the relationship between YA / PA and impedance at each frequency. The table in Figure 6 shows the impedance of the solid electrolytic capacitor 1 at frequencies of 1 MHz, 10 MHz, and 100 MHz when the YA / PA values ​​are 0.1, 0.3, 0.5, 0.7, and 0.9. Table 6 also shows, as a comparative example, the impedance when the cross-sectional shape of the tantalum lead-in wire is circular (i.e., when the tantalum lead-in wire has a cylindrical structure).

[0032] 6, when the cross section of the tantalum lead-in wire 11 is rectangular (YA / PA is 0.1 to 0.9), the impedance value is generally lower than that of the comparative example (the cross section of the tantalum lead-in wire is circular). In particular, when YA / PA is 0.3 to 0.9, the impedance value is lower.

[0033] Here, the value of YA / PA indicates the ratio of the perimeter YA of the cross section of the tantalum lead-in wire 11 to the perimeter PA of the cross section of the capacitor element 10. Thus, the higher the value of YA / PA, the higher the ratio of the perimeter YA of the cross section of the tantalum lead-in wire 11, and the larger the contact area between the tantalum lead-in wire 11 and the anode body 12 of the capacitor element 10. Therefore, it is considered that the higher the value of YA / PA, the larger the contact area between the tantalum lead-in wire 11 and the anode body 12, which reduces the contact resistance and lowers the impedance value of the solid electrolytic capacitor. In addition, it is considered that the higher the value of YA / PA, the larger the surface area of ​​the tantalum lead-in wire 11, which can suppress the phenomenon of high impedance in the high frequency range due to the skin effect, and lowers the impedance value of the solid electrolytic capacitor.

[0034] On the other hand, as the value of YA / PA increases, the value of Wc increases, and the value of Wc / Wd (see FIG. 5) also increases. This may result in a higher pellet crack defect rate. The capacitance of the solid electrolytic capacitor also decreases. Considering this, the value of YA / PA needs to be set in an optimal range, and in this embodiment, it is preferable to set it to 0.3 or more and 0.7 or less.

[0035] Furthermore, in solid electrolytic capacitor 1 according to the present embodiment, Wa / Wb may be set to 0.2 or more and 0.8 or less, and preferably 0.3 or more and 0.7 or less.

[0036] Fig. 7 is a table showing the relationship between Wa / Wb and impedance at each frequency. The table in Fig. 7 shows the impedance of the solid electrolytic capacitor 1 at frequencies of 1 MHz, 10 MHz, and 100 MHz when the Wa / Wb value is 0.2, 0.3, 0.5, 0.7, and 0.8. Table 7 also shows, as a comparative example, the impedance when the cross-sectional shape of the tantalum lead-in wire is circular (i.e., when the tantalum lead-in wire has a cylindrical structure).

[0037] 7, when the cross section of the tantalum lead-in wire 11 is rectangular (Wa / Wb is 0.2 to 0.8), the impedance value is generally lower than that of the comparative example (the cross section of the tantalum lead-in wire is circular). In particular, when Wa / Wb is 0.3 to 0.8, the impedance value is lower.

[0038] Here, the value of Wa / Wb indicates the ratio of the length Wa of the tantalum lead-in wire 11 in the longitudinal direction of the cross section to the length Wb of the longitudinal direction of the cross section of the capacitor element 10. Thus, the higher the value of Wa / Wb, the larger the contact area between the tantalum lead-in wire 11 and the capacitor element 10. Therefore, it is considered that the higher the value of Wa / Wb, the larger the contact area between the tantalum lead-in wire 11 and the anode body 12 of the capacitor element 10 becomes, thereby reducing the contact resistance and lowering the impedance value of the solid electrolytic capacitor.

[0039] On the other hand, when the value of Wa / Wb is high, the length Wa in the longitudinal direction of the cross section of the tantalum lead-through wire 11 is long. When the length Wa in the longitudinal direction of the cross section of the tantalum lead-through wire 11 is long in this way, there is a risk of the pellet crack defect rate increasing. In consideration of this point, it is preferable that the value of Wa / Wb is 0.3 or more and 0.7 or less.

[0040] The noise filter (solid electrolytic capacitor) disclosed in Patent Document 1 aims to maintain low impedance in the high frequency range, but does not fully satisfy the demands for further miniaturization and thinning and low impedance in the high frequency range. Specifically, the noise filter disclosed in Patent Document 1 has a cylindrical structure of tantalum thin wire (i.e., the cross-sectional shape is circular), so that the effects of ESL (Equivalent Series Inductance) and ESR (Equivalent Series Resistance) become large in the high frequency range, and there are cases where the impedance in the high frequency range cannot be sufficiently reduced.

[0041] In contrast, in the solid electrolytic capacitor 1 according to the present embodiment, the contact area between the anode body 12 and the tantalum lead-out wire 11 of the capacitor element 10 can be increased by setting the value of YA / PA and / or the value of Wa / Wb in the above-mentioned range. Therefore, the contact resistance between the anode body 12 and the tantalum lead-out wire is reduced, and the impedance value of the solid electrolytic capacitor can be reduced. In addition, in the solid electrolytic capacitor 1 according to the present embodiment, the surface area of ​​the tantalum lead-out wire can be increased by setting the value of YA / PA in the above-mentioned range. This configuration is a structure that takes into consideration the skin effect that makes it easier for current to flow to the surface side of the conductor in the high frequency range, and by increasing the surface area of ​​the tantalum lead-out wire, i.e., the cross-sectional area through which current flows, the resistance in the high frequency range is reduced, and the impedance value of the solid electrolytic capacitor can be reduced.

[0042] The effects of the present invention will be further described with reference to FIGS. 8, in conventional solid electrolytic capacitor 101, tantalum lead-out wire 111 has a cylindrical structure (i.e., a circular cross-sectional shape), and therefore the contact point between standing portion 123 standing from base portion 121 and tantalum lead-out wire 111 is unstable and forms a single point. For this reason, when solid electrolytic capacitor 101 is tilted and the cathode body and the cathode terminal are bonded with a conductive adhesive, there are cases where poor adhesion occurs or the capacitor element is exposed from the exterior resin.

[0043] In contrast, in the solid electrolytic capacitor 1 according to this embodiment, as shown in the right diagram of FIG. 8, the cross section of the tantalum lead-out wire 11 is rectangular, so that the contact portion between the standing portion 23 and the tantalum lead-out wire 11 is linear and stable. This makes it possible to suppress the occurrence of poor adhesion and poor exposure. Specifically, when the tantalum lead-out wire 111 has a cylindrical structure, the rate of poor exposure was 5.0%. In contrast, when the cross section of the tantalum lead-out wire 11 is rectangular as in this embodiment, the rate of poor exposure was 0.1%, and the occurrence of poor exposure was successfully suppressed.

[0044] Also, as shown in the left diagram of FIG. 9, in conventional solid electrolytic capacitor 101, the contact portion between standing portion 123 and tantalum lead-in wire 111 is a point, and therefore they are electrically connected at a point. This causes a problem of high connection resistance between tantalum lead-in wire 111 and standing portion 123. When the connection resistance is high in this way, the through resistance between the two anode terminals (pedestal portion 21a-standing portion 23a-tantalum lead-in wire 11-standing portion 23b-pedestal portion 21b in FIG. 1) also becomes high. When the through resistance is high, heat generation inside the product increases, which may cause adverse effects on product quality.

[0045] In contrast, in the solid electrolytic capacitor 1 according to this embodiment, as shown in the right diagram of FIG. 9, the cross section of the tantalum lead-out wire 11 is rectangular, so that the contact portion between the standing portion 23 and the tantalum lead-out wire 11 is linear, resulting in a surface connection. This makes it possible to reduce the connection resistance between the tantalum lead-out wire 11 and the standing portion 23. Specifically, when the tantalum lead-out wire 111 has a cylindrical structure, the passing resistance was 7.5 mΩ. In contrast, when the cross section of the tantalum lead-out wire 11 is made rectangular as in this embodiment to reduce the connection resistance, the passing resistance was 6.8 mΩ, and the passing resistance could be reduced.

[0046] Also, as shown in the left diagram of FIG. 10, in the conventional solid electrolytic capacitor 101, the tantalum lead-out wire 111 has a cylindrical structure (i.e., the cross-sectional shape is circular), and therefore, when the tantalum lead-out wire 111 is welded to the standing portion 123, a welding defect may occur. That is, when the tantalum lead-out wire 111 has a cylindrical structure, the volume of the molten wire varies depending on the laser irradiation position, and therefore, the melting manner varies. For example, in the central portion 131 of the tantalum lead-out wire 111, the volume of the molten wire is large, and therefore the wire is difficult to melt. On the other hand, in the end portion side 132 of the tantalum lead-out wire 111, the volume of the molten wire is small, and therefore the wire is easy to melt. In this way, when the tantalum lead-out wire 111 has a cylindrical structure, the ease of melting the wire varies depending on the laser irradiation position, and therefore, a welding defect may occur.

[0047] In contrast, in the solid electrolytic capacitor 1 according to this embodiment, as shown in the right diagram of FIG. 10, the cross section of the tantalum lead-in wire 11 is rectangular, so that when the standing portion 23 and the tantalum lead-in wire 11 are welded, the wire can be melted uniformly regardless of the laser irradiation position. For example, the volume of the wire melted at the laser irradiation position 31 is the same as that at the laser irradiation position 32, so that the tantalum lead-in wire 11 can be stably welded to the standing portion 23. Specifically, when the tantalum lead-in wire 111 has a cylindrical structure, the open defect rate was 1.5%. In contrast, when the cross section of the tantalum lead-in wire 11 is rectangular as in this embodiment, the open defect rate was 0.1% or less, and the tantalum lead-in wire 11 could be stably welded to the standing portion 23.

[0048] Next, configuration examples of the solid electrolytic capacitor according to the present embodiment will be described. Figures 11 to 15 are perspective views showing configuration examples of the solid electrolytic capacitor according to the present embodiment.

[0049] A solid electrolytic capacitor 1_1 shown in Fig. 11 includes a capacitor element 10 and tantalum lead-out wires 11a and 11b. The tantalum lead-out wire 11 penetrates the capacitor element 10 in the penetration direction. The tantalum lead-out wires 11a and 11b are connected to anode lead frames 20a and 20b, respectively. The anode lead frames 20a and 20b include pedestal portions 21a and 21b and standing portions 23a and 23b standing in the vertical direction from the pedestal portions 21a and 21b, respectively. In the configuration example shown in Fig. 11, the standing portions 23a and 23b are joined to the pedestal portions 21a and 21b by welding or the like.

[0050] Moreover, the tantalum lead-through wires 11a, 11b are joined to the standing portions 23a, 23b by welding at welding points 33a, 33b, respectively. The cathode body 15 (see FIG. 3) of the capacitor element 10 is electrically connected to the cathode terminal 22 on the lower surface side of the capacitor element 10. The solid electrolytic capacitor 1_1 is covered with an exterior resin 40. By providing the exterior resin 40, the solid electrolytic capacitor 1_1 can be protected from the external environment.

[0051] The solid electrolytic capacitor 1_2 shown in FIG. 12 includes a capacitor element 10 and tantalum lead-out wires 11a and 11b. The tantalum lead-out wires 11a and 11b are connected to anode lead frames 20a and 20b, respectively. In the configuration example shown in FIG. 12, the standing portions 23a and 23b are formed by bending a part of the base portions 21a and 21b. That is, the standing portions 23a and 23b are formed by bending a part of the base portions 21a and 21b from the capacitor element 10 side toward the outside at bending positions 24 of the base portions 21a and 21b. The other configurations are the same as those of the solid electrolytic capacitor 1_1 shown in FIG. 11. In the configuration example shown in FIG. 12, the standing portions 23a and 23b are formed by bending a part of the base portions 21a and 21b, so that the manufacturing of the anode lead frames 20a and 20b can be simplified.

[0052] The solid electrolytic capacitor 1_3 shown in FIG. 13 includes a capacitor element 10 and tantalum lead-out wires 11a and 11b. The tantalum lead-out wires 11a and 11b are connected to anode lead frames 20a and 20b, respectively. In the configuration example shown in FIG. 13, the standing portions 23a and 23b are formed by bending a part of the base portions 21a and 21b. That is, the standing portions 23a and 23b are formed by bending a part of the base portions 21a and 21b from the outside toward the capacitor element 10 at bending positions 24 of the base portions 21a and 21b. The other configurations are the same as those of the solid electrolytic capacitor 1_1 shown in FIG. 11. In the configuration example shown in FIG. 13, the standing portions 23a and 23b are formed by bending a part of the base portions 21a and 21b, so that the manufacturing of the anode lead frames 20a and 20b can be simplified.

[0053] A solid electrolytic capacitor 1_4 shown in FIG. 14 includes a capacitor element 10 and tantalum lead-out wires 11a and 11b. The tantalum lead-out wires 11a and 11b are connected to anode lead frames 20a and 20b, respectively. In the configuration example shown in FIG. 14, the anode lead frames 20a and 20b have standing portions 26a and 26b formed by forming a part (central portion) of the base portions 21a and 21b into a U-shaped cross section. The standing portions 26a and 26b can be formed by drawing (described in detail later) or bending. The tantalum lead-out wires 11a and 11b are joined to the standing portions 26a and 26b by welding at welding points 33a and 33b, respectively.

[0054] FIG. 15 is a perspective view of the solid electrolytic capacitor 1_4 shown in FIG. 14, seen from the back side. As shown in FIG. 15, the anode lead frames 20a, 20b of the solid electrolytic capacitor 1_4 have upright portions 26a, 26b with a U-shaped cross section at the portions to be welded to the tantalum leads 11a, 11b. In addition, the upright portions 21a, 21b are not U-shaped at the portions closer to the capacitor element 10 than the upright portions 26a, 26b, but are pedestal portions 21a, 21b. This configuration can increase the mounting area of ​​the anode terminals (pedestal portions 21a, 21b). The rest of the configuration is the same as that of the solid electrolytic capacitor 1_1 shown in FIG. 11. In the configuration example shown in FIG. 14 and FIG. 15, the upright portions 26a, 26b are formed by making the central portions of the pedestal portions 21a, 21b U-shaped in cross section, so that the manufacture of the anode lead frames 20a, 20b can be simplified.

[0055] Figures 16 and 17 are perspective views for explaining a manufacturing example of the solid electrolytic capacitor according to the present embodiment, and are views for explaining a manufacturing example of the solid electrolytic capacitor 1_4 shown in Figures 14 and 15. Figure 16 is a perspective view of the solid electrolytic capacitor 1_4 as viewed from the top side, and Figure 17 is a perspective view of the solid electrolytic capacitor 1_4 as viewed from the back side.

[0056] As shown in Fig. 16, when manufacturing the solid electrolytic capacitor 1_4, first, regions 51a and 51b of a plate-like member 50 are subjected to drawing to form protruding portions 52a and 52b. The protruding portions 52a and 52b correspond to the standing portions 26a and 26b shown in Fig. 14 and Fig. 15. Then, the capacitor element 10 is arranged so that the upper surfaces of the protruding portions 52a and 52b contact the lower surfaces of the tantalum lead-through wires 11a and 11b, respectively.

[0057] Next, the welding points 33a, 33b of the tantalum leads 11a, 11b are irradiated with a laser, respectively, to weld the tantalum leads 11a, 11b to the protrusions 52a, 52b. After that, the exterior resin 40 is formed so as to cover the capacitor element 10 and the tantalum leads 11a, 11b. At this time, the exterior resin 40 is prevented from penetrating into the rear surface side of the protrusions 52a, 52b (see FIG. 17). Then, by cutting by dicing at the cutting positions 55a, 55b shown in FIG. 17, the solid electrolytic capacitor 1_4 shown in FIG. 14 and FIG. 15 can be formed.

[0058] 14 and 15, the back side of standing portions 26a, 26b (corresponding to the back side of protrusions 52a, 52b in FIGS. 16 and 17) is hollow. Therefore, when mounting solid electrolytic capacitor 1_4, solder flows into the space on the back side of standing portions 26a, 26b to easily form a solder fillet, thereby reducing the mounting area of ​​solid electrolytic capacitor 1_4 and enabling solid electrolytic capacitor 1_4 to be reliably mounted on a board.

[0059] While the present invention has been described above in accordance with the above-described embodiment, the present invention is not limited to the configuration of the above-described embodiment, and naturally includes various modifications, alterations, and combinations that may be made by a person skilled in the art within the scope of the invention as defined in the claims of the present application. [Explanation of symbols]

[0060] 1, 1_1~1_4 Solid electrolytic capacitor 10 Capacitor element 11, 11a, 11b Tantalum lead wire 12 Anode body 13 Dielectric layer 14 Solid electrolyte layer 15 Cathode body 20, 20a, 20b Anode lead frame 21, 21a, 21b Pedestal 22 Cathode terminal 23, 23a, 23b Standing section 24 Folding position 26a, 26b Standing section 31, 32 Laser irradiation position 33a, 33b Welding points 40 Exterior resin 50 Plate-shaped member 51a, 51b area 52a, 52b Convex portion 55a, 55b cutting position

Claims

1. A tantalum lead wire; a capacitor element including: an anode body made of a valve metal covering a periphery of a central portion of the tantalum lead-through; a dielectric layer formed on a surface of the anode body; a solid electrolyte layer formed on a surface of the dielectric layer; and a cathode body formed on a surface of the solid electrolyte layer; the tantalum lead-through passes through the capacitor element in a penetration direction; a cross section of the tantalum lead-through wire and the capacitor element perpendicular to the through-direction has a rectangular shape with a longitudinal direction extending horizontally; where Wc is a length in a vertical direction of a cross section of the tantalum lead-through wire perpendicular to the through-through direction, and Wd is a length in a vertical direction of a cross section of the capacitor element perpendicular to the through-through direction, Wc / Wd is 0.1 or more and 0.3 or less, where YA is a perimeter of a cross section of the tantalum lead-through wire perpendicular to the through-through direction, and PA is a perimeter of a cross section of the capacitor element perpendicular to the through-through direction, YA / PA is 0.5 or more and 0.7 or less, the tantalum lead-through wire constitutes a first anode lead-through wire and a second anode lead-through wire on either side of the capacitor element in the penetration direction, the first anode lead wire is welded to a first anode lead frame; the second anode lead wire is welded to a second anode lead frame; each of the first anode lead frame and the second anode lead frame includes a base portion connected to a substrate and a standing portion having a U-shaped cross section formed on a part of the base portion; the first anode lead-wire and the second anode lead-wire are welded to an upright portion of the first anode lead frame and an upright portion of the second anode lead frame, respectively; the first anode lead frame and the second anode lead frame are each disposed at a position not overlapping with the capacitor element in a plan view, the pedestal portion of the first anode lead frame is provided closer to the capacitor element than the standing portion of the first anode lead frame, the pedestal portion of the second anode lead frame is provided closer to the capacitor element than the standing portion of the second anode lead frame, the capacitor element, the first anode lead-wire, the second anode lead-wire, the first anode lead frame, and the second anode lead frame are covered with an exterior resin, The rear surface side of the standing portion is configured to be hollow and not filled with the exterior resin. Solid electrolytic capacitor.

2. 2. The solid electrolytic capacitor according to claim 1, wherein the Wc / Wd is 0.3 or less.

3. 3. The solid electrolytic capacitor according to claim 1, wherein Wa / Wb is 0.2 or more and 0.8 or less, where Wa is a length in a horizontal direction of a cross section perpendicular to the through-direction of the tantalum lead-through wire, and Wb is a length in a horizontal direction of a cross section of the capacitor element perpendicular to the through-direction of the tantalum lead-through wire.

4. 4. The solid electrolytic capacitor according to claim 3, wherein the Wa / Wb is 0.3 or more and 0.7 or less.

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