Capacitor, method for manufacturing capacitor, and method for mounting capacitor

Abstract

The purpose of the technology disclosed in the present invention is to suppress the retention of electrolytic solution in the gap, thereby suppressing the reduction of insulation resistance, even if a gap is generated between terminal leads. The capacitor (2) includes a capacitor body (4), a base (6) and a resin layer (8-1). The capacitor body includes an outer casing (10), a sealing member (14) installed on the opening of the outer casing, and terminal leads (16-1, 16-2) passing through the sealing member. The base is arranged on the sealing member side of the capacitor body, and has insertion holes (18-1, 18-2) for the terminal leads to be inserted and exposed to the mounting surface side, and a protrusion (20) surrounding the insertion holes. The resin layer is at least arranged between the base and the sealing member. The base and the resin layer are in non-adhesive contact or separation in at least a portion, or the adhesive force of the resin layer relative to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the installation process.

Description

Technical Field

[0001] The present disclosure relates to a capacitor having a base, a method for manufacturing the capacitor, and a method for mounting the capacitor. Background Art

[0002] The capacitor has a base, for example, and the terminal lead of the capacitor is led out to the outer side of the base and bent, for example, and is soldered to a wiring board such as a circuit substrate. Capacitors used for such mounting are called surface mounted capacitors. Such surface mounted capacitors are highly versatile and are used, for example, in automobiles.

[0003] When the capacitor is set outdoors, such as in a car, the ambient temperature around the capacitor rises. Therefore, the capacitor needs to withstand high temperature environments. For example, a resin layer is formed between the sealing member and the base of the capacitor to improve the airtightness of the capacitor (for example, Patent Document 1). According to this structure, the heat resistance of the capacitor can be improved. The base of such a capacitor has a through insertion hole, and the terminal lead of the capacitor passes through the through insertion hole and is arranged on the outside of the base, that is, the mounting surface side. When the base also includes a protrusion that separates the through insertion hole from the resin layer, the protrusion is used to suppress the resin used to form the resin layer from flowing into the through insertion hole. That is, the resin used to form the resin layer is prevented from flowing out to the outside of the capacitor through the through insertion hole, thereby suppressing defects in the installation of the capacitor.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 062411 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, if a gap is formed between the outside of the sealing member and the resin layer, the gas of the electrolytic solution that has passed through the sealing member may reach the gap and return to the electrolytic solution. If the conductive electrolytic solution is retained between the terminal leads of the capacitor, the insulation resistance between the terminal leads may be reduced, thereby possibly damaging the reliability of the capacitor.

[0009] Therefore, a first object of the technology disclosed in the present invention is to suppress accumulation of an electrolytic solution in a gap even when a gap is generated between the outside of a sealing member and a resin layer, thereby suppressing a decrease in insulation resistance.

[0010] In addition, a second object of the technology disclosed in the present invention is to suppress a decrease in reliability of a capacitor.

[0011] Means for solving problems

[0012] According to a first aspect of the present disclosure, a capacitor includes a capacitor body, a base, and a resin layer. The capacitor body includes an outer casing, a sealing member installed at an opening of the outer casing, and a terminal lead passing through the sealing member. The base is provided on the sealing member side of the capacitor body, and has an insertion hole through which the terminal lead is inserted and exposed to the mounting surface side, and a protrusion surrounding the insertion hole. The resin layer is at least arranged between the base and the sealing member. The base and the resin layer are separated or in non-adhesive contact at least in part, or the adhesive force of the resin layer relative to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the mounting process.

[0013] In the above capacitor, the adhesive force of the resin layer to the base may be smaller than the adhesive force of the resin layer to the sealing member in at least a part.

[0014] In the above capacitor, a difference in expansion coefficient between the base and the resin layer may be larger than a difference in expansion coefficient between the sealing member and the resin layer.

[0015] In the above capacitor, the boundary between the base and the resin layer may include a contact surface, a separation surface, or a contact surface and a separation surface between the base and the resin layer, and a gas passage for gas to pass through may be formed by the boundary.

[0016] In the above capacitor, a boundary between the protruding portion and the sealing member may communicate with the outside of the capacitor through the gas passage.

[0017] In the above capacitor, the resin layer may be further arranged inside the insertion hole.

[0018] In the above capacitor, the base may further include a peripheral wall disposed outside the outer case, and the resin layer may be further disposed between the peripheral wall and the outer case.

[0019] According to a second aspect of the present disclosure, a method for manufacturing a capacitor includes the following steps: manufacturing a capacitor body including an outer casing, a sealing member mounted on an opening of the outer casing, and a terminal lead penetrating the sealing member; manufacturing a base having a through-hole and a protrusion surrounding the through-hole; arranging the base on the sealing member side of the capacitor body, and inserting the terminal lead through the through-hole to expose it to the mounting surface side; and forming a resin layer between the base and the sealing member. The base and the resin layer are separated or contacted in a non-adhesive manner at least in part, or the adhesive force of the resin layer relative to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during mounting.

[0020] According to a third aspect of the present disclosure, a method for mounting a capacitor includes the following steps: a mounting step of mounting the capacitor on a circuit substrate by means of solder; and a reflow step of bonding the circuit substrate and the capacitor by heat treating the solder. The base and the resin layer are separated by the heat treatment to form a gas passage.

[0021] Effects of the Invention

[0022] According to the technology disclosed in the present invention, any of the following effects can be obtained.

[0023] (1) The base and the resin layer are in non-adhesive contact or separation in at least a portion, or the adhesive force of the resin layer relative to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the installation process. Therefore, the gas of the electrolyte passing through the sealing member can flow at the boundary between the base and the resin layer in the portion where the base is in non-adhesive contact or separation, and the gas can be discharged to the outside of the capacitor. In addition, in the portion where the adhesive force of the resin layer relative to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the installation process, the resin layer is separated from the base due to heating during the installation process. Therefore, the gas of the electrolyte passing through the sealing member can flow at the boundary between the base and the resin layer of the heated capacitor, and the gas can be discharged to the outside of the capacitor.

[0024] (2) Since the accumulation of gas in the electrolyte between the terminal leads is suppressed, a decrease in insulation resistance between the terminal leads can be avoided.

[0025] (3) The base and the resin layer are in non-adhesive contact or separation in at least a portion, or the adhesive force of the resin layer relative to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the mounting process. Therefore, when the capacitor is at least mounted on a wiring board such as a circuit substrate, the resin layer is separated from the base, so the force applied to the boundary between the sealing member and the resin layer is reduced, thereby maintaining the adhesion of the resin layer to the sealing member. Therefore, the bonding portion between the resin layer and the sealing member can suppress the evaporation of the electrolyte, thereby improving the stability of the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a cross-sectional view showing an example of the capacitor according to the first embodiment.

[0027] Figure 2 It is a diagram showing a base of a capacitor.

[0028] Figure 3 It is a cross-sectional view showing an example of a capacitor after heating.

[0029] Figure 4 It is a diagram for explaining the effect of a capacitor.

[0030] Figure 5 FIG. 1 is a diagram showing an example of a capacitor according to a modified example. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments and the like will be described with reference to the drawings.

[0032] First embodiment

[0033] Figure 1 A is a cross-sectional view showing an example of the capacitor according to the first embodiment, Figure 1 B is Figure 1 A partial enlarged view of A. Figure 1 In the figure, a part of the capacitor body is omitted. Figure 2 A is a plan view of the base of the capacitor, showing a surface portion of the base that is provided on the main body installation surface of the capacitor body and on the sealing member side. Figure 2 B is a bottom view of the base, showing the opposite side of the main body setting surface and the outer side and mounting surface of the base. Figure 2 The base shown in A is added with an imaginary line L1, a midpoint O and a center line L2. Figure 1 and Figure 2 The structure shown is an example, and the technology disclosed in this disclosure is not limited to this structure.

[0034] The capacitor 2 is an example of an electronic component, such as an electrolytic capacitor or an electric double layer capacitor. The capacitor 2 includes a capacitor body 4, a base 6, and resin layers 8-1 and 8-2. The capacitor body 4 includes an outer casing 10, a capacitor element 12, and a sealing member 14. The base 6 is provided on the sealing member 14 side of the capacitor body 4. The resin layer 8-1 is arranged in the gap between the base 6 and the capacitor body 4, and the resin layer 8-2 is arranged inside the through insertion holes 18-1 and 18-2 formed in the base 6. The capacitor 2 can be mounted on a wiring board such as a circuit substrate.

[0035] The resin layer 8-1 is opposite to the base 6 via the boundary 15-1, and the resin layer 8-2 is opposite to the base 6 via the boundary 15-2. The boundary 15-1, 15-2 is the boundary between the base 6 and the resin layers 8-1, 8-2, and is formed by the opposing surface of the base 6 and the opposing surface of the resin layers 8-1, 8-2. The base 6 and the resin layers 8-1, 8-2 may be in contact or separated without adhesion in at least a portion, or the adhesive force of the resin layers 8-1, 8-2 to the base 6 may be smaller than the force generated at the boundary 15-1, 15-2 at the mounting process temperature in at least a portion. During the mounting process, that is, in the process of mounting the capacitor 2 on the wiring board, the capacitor 2 and the wiring board are heated to the mounting process temperature. Therefore, thermal deformation such as expansion or contraction occurs in at least one of the base 6 or the resin layers 8-1, 8-2, and force is generated between the base 6 and the resin layers 8-1, 8-2 due to the thermal deformation. The force generated by the thermal deformation is, for example, a force to peel the resin layers 8-1 and 8-2 from the base 6. The process of mounting the capacitor 2 on the wiring board includes, for example, a heating process such as a reflow process, and the mounting process temperature is the temperature of the capacitor 2 or the periphery of the capacitor 2 in the heating process, for example, 260°C. The force generated at the boundary portions 15-1 and 15-2 is generated, for example, due to the expansion difference between the base 6 and the resin layers 8-1 and 8-2 at the mounting process temperature. In the portion where the base 6 and the resin layers 8-1 and 8-2 are in non-adhesive contact (hereinafter referred to as the "contact portion"), the resin layers 8-1 and 8-2 are not bonded to the base 6 by bonding based on intermolecular forces such as hydrogen bonds and van der Waals forces or mechanical bonding of the concave and convex shapes, and the resin layers 8-1 and 8-2 are in contact with the base 6, for example, and the boundary portions 15-1 and 15-2 form a contact surface. In addition, the resin layers 8-1 and 8-2 may be separated from the base 6 at the portion where the base 6 and the resin layers 8-1 and 8-2 are separated (hereinafter referred to as "separated portion"), and the boundary portions 15-1 and 15-2 may form a separated surface. In the portion where the base 6 and the resin layers 8-1 and 8-2 are bonded, that is, the portion other than the contact portion and the separated portion described above, the resin layers 8-1 and 8-2 are bonded to the base 6 by bonding based on intermolecular forces such as hydrogen bonding and van der Waals force or mechanical bonding of the concave and convex shapes, and the boundary portions 15-1 and 15-2 may form a bonded surface. The boundary portions 15-1 and 15-2 may be a contact surface, a separated surface, a bonded surface, or a plurality of these surfaces.

[0036] It is preferred that the adhesive force of the resin layers 8-1 and 8-2 to the base 6 is partially or entirely smaller than the adhesive force of the resin layers 8-1 and 8-2 to the sealing member 14. In this case, even if the mutually bonded resin layers 8-1 and 8-2 and the base 6 are separated by heating, the adhesion of the resin layers 8-1 and 8-2 to the sealing member 14 can be maintained.

[0037] The difference in expansion coefficient between the base 6 and the resin layers 8-1, 8-2 is preferably greater than the difference in expansion coefficient between the sealing member 14 and the resin layers 8-1, 8-2. In this case, the force generated by heating at the boundaries 15-1, 15-2 is greater than the force generated by heating at the boundary 15-3 between the sealing member 14 and the resin layer 8-1.

[0038] The difference between each adhesive force and each expansion coefficient can be adjusted, for example, by adjusting the combination of materials of the base 6, the resin layers 8-1, 8-2, and the sealing member 14. In addition, in order to improve the adhesive force of the resin layers 8-1, 8-2 to the sealing member 14, the sealing member 14 after surface treatment can also be bonded to the resin layers 8-1, 8-2. The surface treatment of the sealing member 14 is, for example, surface removal for removing attachments such as a release agent. In addition, regarding the adhesive force of the resin layers 8-1, 8-2 to the base 6, when the resin layers 8-1, 8-2 are separated from the base 6 in the capacitor 2 heated at the mounting process temperature, it can be judged that the adhesive force is smaller than the force generated at the boundary portions 15-1, 15-2. In the case where the resin layers 8-1, 8-2 continue to be bonded to the base 6 in the capacitor 2 heated at the mounting process temperature, it can be judged that the adhesive force is greater than the force generated at the boundary portions 15-1, 15-2.

[0039] The capacitor body 4 can be used as a capacitor in its single form. A capacitor element 12 is enclosed in an outer case 10, and a sealing member 14 is attached to an opening of the outer case 10. The sealing member 14 is formed of, for example, insulating rubber.

[0040] The outer case 10 is, for example, a bottomed cylindrical aluminum case. The open front end of the outer case 10 is bent at a substantially right angle, so the end of the outer case 10 opposite to the bottom (hereinafter referred to as an "open end") has a flat surface.

[0041] Capacitor element 12 is a wound element in which anode foil, cathode foil and separator are wound with a separator interposed therebetween, and terminal leads 16 - 1 and 16 - 2 are led out from the same element surface. Capacitor element 12 is impregnated with an electrolyte solution.

[0042] The terminal leads 16-1 and 16-2 are formed of, for example, a metal with good conductivity. The terminal lead 16-1 is an anode-side terminal, and has a lead portion extending from the anode foil of the capacitor element 12 and a terminal portion mounted on a wiring board. The lead portion and the terminal portion are connected and integrated by welding or the like. The terminal lead 16-2 is a cathode-side terminal, and has a lead portion extending from the cathode foil of the capacitor element 12 and a terminal portion mounted on a wiring board. Similar to the terminal lead 16-1, the lead portion and the terminal portion are connected and integrated by welding or the like. The lead portion is, for example, cylindrical, and the terminal portion is, for example, flattened on the mounting surface side mounted on the wiring board so that the cross section is rectangular. The terminal leads 16-1 and 16-2 pass through the sealing member 14 and are exposed to the outside of the capacitor body 4.

[0043] The base 6 is provided on the sealing member 14 side of the capacitor body 4. The base 6 is formed of an insulating plate such as an insulating synthetic resin. The insulating synthetic resin only needs to have heat resistance to the extent that it can withstand heating when installed on a wiring board, and may be, for example, polyester resins such as polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), and polyethylene terephthalate (PET), polyamide resins such as nylon, polyphenylene sulfide (PPS), polyphenylene oxide (PPO), urea resin, liquid crystal polymer (LCP), phenolic resin, or epoxy resin. The base 6 has through insertion holes 18-1, 18-2, a protrusion 20, a peripheral wall 22, and guide grooves 24-1, 24-2. In addition, as Figure 2 As shown in FIG. 1A , the base 6 has supporting protrusions 26 - 1 and 26 - 2, a resin injection hole 30, a through hole 32 and a shielding portion 34. Figure 2 As shown in FIG. 8B , the base 6 has step portions 36 , 38 and a support portion 40 .

[0044] The insertion holes 18-1 and 18-2 are holes formed at positions corresponding to the terminal leads 16-1 and 16-2. The pair of terminal leads 16-1 and 16-2 protruding from the capacitor body 4 pass through the pair of insertion holes 18-1 and 18-2 formed in the base 6 and are led out to the outer side of the base 6, that is, the mounting surface side of the base 6. Figure 2 As shown in A, the cross-sectional shape of the through-insertion holes 18 - 1 , 18 - 2 is, for example, a rectangular shape with rounded corners.

[0045] The protrusion 20 is provided on the main body installation surface of the base 6. The protrusion 20 is formed around the insertion holes 18-1 and 18-2, and surrounds the insertion holes 18-1 and 18-2. The protrusion 20 is opposite to the sealing member 14, and separates the resin layer 8-1 adjacent to the protrusion 20 from the insertion holes 18-1 and 18-2. The height of the protrusion 20 is set, for example, to a height difference H ( Figure 1B). When the height of the protrusion 20 is the height difference H, the open end of the outer case 10 contacts the base 6, and the protrusion 20 of the base 6 contacts the sealing member 14. The outer case 10 and the protrusion 20 function as a supporting portion, whereby the arrangement of the base 6 is stable, and the capacitor body 4 is supported by both the peripheral portion and the central portion. In addition, the protrusion 20 in contact with the sealing member 14 can suppress the resin injected between the base 6 and the sealing member 14 to form the resin layer 8-1 from invading the insertion holes 18-1 and 18-2 at a high level. In addition, the protrusion 20 contacts the sealing member 14, thereby suppressing the formation of a gap.

[0046] For example Figure 2 As shown in A of FIG. 1 , the protrusion 20 has a substantially rectangular shape with a constriction in the middle of the longitudinal direction. The protrusion 20 has a setback portion 44 in the middle of the longitudinal direction, and the setback portion 44 forms a constriction. The protrusion 20 has a flat portion 46 at the end of the longitudinal direction. For example, the protrusion 20 has a Figure 2 The imaginary line L1 shown in A is symmetrical in shape and has a shape relative to Figure 2 The shape is symmetrical about the center line L2 shown in A. The imaginary line L1 is a line connecting the through-hole 18-1 and the through-hole 18-2, and the center line L2 is a line passing through the middle point O between the through-hole 18-1 and the through-hole 18-2 and perpendicular to the imaginary line L1.

[0047] The protrusion 20 has grooves 48 and 50 on the surface facing the sealing member 14. The groove 48 is formed so that the height of the middle portion between the insertion hole 18-1 and the insertion hole 18-2 is partially lowered, and extends toward the resin injection hole 30 and the through hole 32 to form a resin passage. The groove 48 can adjust the flow rate of the resin flowing in the groove 48 according to the width of the groove 48.

[0048] The groove 50 extends from the flat portion 46 of the protrusion 20 to the insertion holes 18-1 and 18-2 to form an air passage. The groove 50 can discharge the air squeezed out by the resin injection to the outside through the groove 50. In order to form the resin layer 8-2, the groove 50 can also allow a part of the injected resin to pass through so that the resin reaches the insertion holes 18-1 and 18-2. The width, depth, setting interval or number of the groove 50 are appropriately set, for example, in consideration of the passage of air and the suppression of the intrusion of resin. The groove 50 is, for example, formed only on the surface of the through hole 32 side of the protrusion 20. Therefore, it is possible to suppress the resin from directly passing through the groove 50 and flowing to the insertion holes 18-1 and 18-2. That is, the resin injected from the resin injection hole 30 flows to the space on the through hole 32 side in the space between the sealing member 14 and the base 6 due to the injection pressure, and then the resin is pressed into the groove portion 50 due to the pressing force of the resin filled in the space, so that the resin can flow to the groove portion 50 at a pressure lower than the injection pressure. Therefore, the amount of resin flowing through the insertion holes 18-1 and 18-2 can be adjusted to a degree that the resin does not flow into the mounting surface of the base 6 and affect the connectivity between the terminal leads 16-1 and 16-2 and the wiring board.

[0049] The peripheral wall 22 is arranged around the base 6 and outside the open end of the outer casing 10, and surrounds the open end of the outer casing 10. The inner side of the peripheral wall 22 is along the outer circumference of the bottomed cylindrical outer casing 10, so it has a circular shape. The peripheral wall 22 can be higher than the protrusion 20, or it can be the same height as the protrusion 20 or lower than the protrusion 20.

[0050] The guide grooves 24-1 and 24-2 are formed on the mounting surface of the base 6 and extend outward from the through insertion holes 18-1 and 18-2. The terminal portions of the terminal leads 16-1 and 16-2 are bent in opposite directions along the guide grooves 24-1 and 24-2 and are arranged in the guide grooves 24-1 and 24-2. Therefore, the guide grooves 24-1 and 24-2 guide the terminal portions of the terminal leads 16-1 and 16-2. In addition, guide protrusions may be provided on the mounting surface of the base 6 instead of the guide grooves 24-1 and 24-2. The stability of the capacitor 2 during installation can be ensured by the guide grooves 24-1 and 24-2 or the guide protrusions.

[0051] The support protrusions 26-1 and 26-2 are examples of protrusions that support the open end of the outer casing 10. The support protrusions 26-1 and 26-2 are adjacent to the resin layer 8-1 and are partially formed at a position where the base 6 contacts the open end of the outer casing 10. Figure 2As shown in A, the support protrusions 26-1 and 26-2 are formed on the main body setting surface of the base 6 and are located closer to the inner side of the base 6 than the peripheral wall 22. The support protrusion 26-1 is in the shape of an arc having a width, and covers the outer side of the resin injection hole 30 and the protrusion 20 in the shape of an arc. The support protrusion 26-2 has a circular shape and is arranged on the outer side of the through hole 32. In the forming portion of the support protrusions 26-1 and 26-2, the open end of the outer shell 10 contacts the support protrusions 26-1 and 26-2. In the disconnected portion of the support protrusions 26-1 and 26-2, the open end of the outer shell 10 is separated from the base 6, and a gap is formed between the open end of the outer shell 10 and the base 6. The gap between the open end of the outer shell 10 and the base 6 forms a resin path for allowing the resin to flow between the peripheral wall 22 of the base 6 and the outer peripheral surface of the outer shell 10.

[0052] like Figure 2 As shown in A, the resin injection hole 30 is formed on the center line L2. The resin injection hole 30 is an example of a through-hole for injecting resin, and the resin injection hole 30 is formed at an equal distance from the through-holes 18-1 and 18-2.

[0053] like Figure 2 As shown in FIG. 1A , the through hole 32 is formed on the center line L2. The through hole 32 is formed, for example, at the terminal portion where the resin flows in the end during the resin injection, and is used to confirm the resin that has reached the terminal portion along the resin injection path. The through hole 32 is also used to discharge the air squeezed out by the resin injection. The through hole 32 makes it easy to confirm the resin filling state and to discharge the air.

[0054] The shielding portion 34 is disposed around the through hole 32 and between the through hole 32 and the resin injection hole 30. The shielding portion 34 prevents the resin injected from the resin injection hole 30 from invading the through hole 32 from the resin injection hole 30 side of the through hole 32. That is, the shielding portion 34 prevents the through hole 32 from being buried with the resin before the resin spreads throughout the formation area of ​​the resin layer 8-1. The shielding portion 34 surrounds a portion (e.g., two-thirds) of the periphery of the through hole 32. The shielding portion 34 preferably surrounds more than 50% of the periphery of the through hole 32, and preferably surrounds more than 66%. For example, Figure 2 As shown in A, for example, 10% of the periphery of the through hole 32 only needs to be open without being surrounded by the shielding portion 34 .

[0055] like Figure 2 As shown in FIG. 1B , a step portion 36 is formed on the mounting surface of the base 6 and around the resin injection hole 30. The step portion 36 is used, for example, to align a resin injection device connected to the resin injection hole 30 during resin injection. The step portion 36 provides a space for preventing the resin near the resin injection hole 30 from protruding beyond the mounting surface of the base 6.

[0056] like Figure 2As shown in FIG. 1B , a step portion 38 is formed on the mounting surface of the base 6 and around the through hole 32 . The step portion 38 provides a space for preventing the resin near the through hole 32 from protruding beyond the mounting surface of the base 6 .

[0057] like Figure 2 As shown in B, the support portion 40 is formed on the mounting surface of the base 6 and near the corner of the base 6. When the capacitor 2 is mounted on the wiring board, the support portion 40 can stabilize the posture of the capacitor 2 by point contact.

[0058] The resin layer 8-1 is provided on the outside of the protrusion 20 and on the inside of the open end of the outer casing 10, and is provided between the base 6 and the sealing member 14. The resin layer 8-1 seals the outer side surface of the sealing member 14. The resin layer 8-2 is provided inside the through-holes 18-1 and 18-2. The resin layer 8-2 suppresses the gap between the inner surface of the through-holes 18-1 and 18-2 and the terminal leads 16-1 and 16-2. The resin layers 8-1 and 8-2 can improve the sealing performance of the capacitor body 4 and can discharge the electrolytic solution reaching the outside of the sealing member 14. The resin layer 8-2 can be formed by allowing the resin injected from the resin injection hole 30 to reach the through-holes 18-1 and 18-2, or by adding resin from the mounting surface of the base 6.

[0059] The resin forming the resin layers 8-1 and 8-2 is, for example, a sealing resin for sealing the outside of the sealing member 14. It is in liquid form when filling, but solidifies after filling. When filling, the liquid resin fills the gap between the capacitor body 4 and the base 6 and a part of the inside of the insertion holes 18-1 and 18-2. After filling, the resin solidifies to form the resin layers 8-1 and 8-2. The resin forming the resin layers 8-1 and 8-2 only needs to have affinity with the base 6, the outer casing 10 and the sealing member 14 and have gas blocking properties. It is preferred that the linear expansion coefficient be close to that of aluminum (about 23×10 -6 / °C), the shrinkage during curing is small, and it is non-hygroscopic. The resin can be, for example, epoxy resin, alkyd resin, polyurethane resin, thermosetting resin or ultraviolet curing resin. In addition, the epoxy resin can be, for example, a two-component mixed epoxy resin using an acid anhydride, or a one-component epoxy resin.

[0060] [Capacitor manufacturing process]

[0061] The manufacturing process of the capacitor is an example of the manufacturing method of the capacitor disclosed in the present invention, and the manufacturing process includes a process of forming the capacitor body 4, a process of forming the base 6, a process of installing the base 6 on the capacitor body 4, a process of molding the terminal leads 16-1 and 16-2, and a process of injecting resin.

[0062] In the process of forming the capacitor body 4, first, a separator is interposed between an anode foil connected to the terminal lead 16-1 and a cathode foil connected to the terminal lead 16-2, and the anode foil, the cathode foil and the separator are wound to form the capacitor element 12. After the capacitor element 12 is impregnated with an electrolyte and the capacitor element 12 is sealed in the outer case 10, a sealing member 14 is attached to the opening of the outer case 10 to form the capacitor body 4. The outer case 10 is formed of aluminum, for example.

[0063] In the step of forming the base 6, the base 6 is formed into the above-mentioned shape by insulating synthetic resin. In addition, in the present embodiment, the electrolytic capacitor is formed by impregnating the capacitor element 12 with an electrolyte, but it is not limited to an electrolytic capacitor. The capacitor 2 may also be a hybrid capacitor in which the capacitor element 12 containing a conductive polymer impregnated with an electrolyte to form a solid electrolyte layer.

[0064] In the mounting step of the base 6, the terminal leads 16-1 and 16-2 of the capacitor body 4 are inserted through the insertion holes 18-1 and 18-2 of the base 6. Then, the base 6 is moved and mounted on the sealing member 14 side of the capacitor body 4. In this mounting step, the protrusion 20 of the base 6 is arranged on the sealing member 14 side.

[0065] In the molding process of the terminal leads 16-1, 16-2, the terminal leads 16-1, 16-2 are bent along the guide grooves 24-1, 24-2 of the base 6, and the terminal portions of the terminal leads 16-1, 16-2 are arranged in the guide grooves 24-1, 24-2. The base 6 is fixed to the capacitor body 4 by this molding process.

[0066] In the resin injection process, the liquid resin injected from the resin injection hole 30 of the base 6 is filled into the gap between the capacitor body 4 and the base 6. The resin spreads around the resin injection hole 30, and flows toward the through hole 32 through the gap between the protrusion 20 and the supporting protrusion 26-1 or the groove 48, thereby spreading around the through hole 32 and the shielding portion 34. In addition, a portion of the resin flows to the outside of the capacitor body 4 through the outside of the end of the supporting protrusion 26-1. In addition, a portion of the resin may also flow into the inside of the insertion holes 18-1 and 18-2 through the groove 50. The injected resin forms a resin layer 8-1 between the capacitor body 4 and the base 6, and forms a resin layer 8-2 inside the insertion holes 18-1 and 18-2. The resin is injected using a resin injection device such as a dispenser.

[0067] [Mounting capacitors on wiring boards]

[0068] The capacitor mounting step is an example of the capacitor mounting method of the present disclosure, and is, for example, a capacitor reflow soldering step, and includes, for example, a solder applying step, a capacitor mounting step, and a heating step.

[0069] In the solder application process, solder paste is applied to the pad of the wiring board by, for example, screen printing. The solder paste contains, for example, flux and a plurality of solder particles dispersed in the flux.

[0070] In the capacitor mounting process, the capacitor 2 is mounted on the wiring board via the solder paste so that the terminal leads 16 - 1 and 16 - 2 of the capacitor 2 come into contact with the solder paste on the pad.

[0071] In the heating process, the wiring board and the capacitor 2 mounted on the wiring board are placed in a heating furnace such as a reflow furnace and heated at the above-mentioned mounting processing temperature. The solder paste is converted into solder by the heat treatment, and the capacitor 2 is bonded to the wiring board. Thus, the capacitor 2 is mounted on the wiring board.

[0072] During the heating process, a force is generated due to the expansion difference between the base 6 and the resin layers 8-1, 8-2, and the force acts on the bonded boundary portions 15-1, 15-2. Therefore, the resin layers 8-1, 8-2 are separated from the base 6 in part or in the whole of the boundary portions 15-1, 15-2. The separated boundary portions 15-1, 15-2 form a separation surface. The separation surface can be a contact surface where two surfaces are in contact, or a separation surface where two surfaces are separated. In addition, in this specification, "separation" is a term used to indicate that two bonded objects are separated into non-bonded objects. The "separation surface" is a surface formed by the separation of the resin layers 8-1, 8-2 and the base 6.

[0073] like Figure 3 As shown, the capacitor 2 after the heating process has, for example, a separation surface formed by boundary portions 15-1 and 15-2. The separation surface has a separation surface, forming gas passages 52-1 and 52-2. In the capacitor 2 after the heating process, the boundary portion 54 between the protrusion 20 and the sealing member 14 is connected to the outside of the capacitor 2 through the gas passages 52-1 and 52-2.

[0074] According to the first embodiment, the following operations or effects can be obtained.

[0075] (1) The electrolyte gas passing through the sealing member 14 flows along the contact surface, the separation surface, the separation surface, or between the plurality of surfaces formed by the boundary portions 15-1 and 15-2. Figure 4The gas flowing in the boundary portion 15-2 is discharged to the outside of the capacitor 2. In addition, since the capacitor body 4 is separated from the base 6 between the support protrusions 26-1 and 26-2, the gas flowing in the boundary portion 15-1 is also discharged to the outside of the capacitor 2. Therefore, it is possible to suppress the stagnation of the gas of the electrolyte between the terminal leads 16-1 and 16-2, thereby avoiding the reduction of the insulation resistance between the terminal leads 16-1 and 16-2. As a result, for example, the risk of short circuit of the terminal leads 16-1 and 16-2 can be reduced.

[0076] (2) Since the heated resin layer 8-1 is separated from the base 6, the force applied to the boundary portion 15-3 between the sealing member 14 and the resin layer 8-1 is reduced, thereby maintaining the adhesion of the resin layer 8-1 to the sealing member 14. Therefore, the adhesion portion between the resin layer 8-1 and the sealing member 14 can suppress the evaporation of the electrolyte, thereby improving the stability of the capacitor 2. In addition, the adhesion of the resin layer 8-1 to the sealing member 14 can be maintained, and the vibration resistance can be improved.

[0077] Second embodiment

[0078] In the first embodiment, during the capacitor mounting process, the resin layers 8-1 and 8-2 are separated from the base 6 to form a separation surface. In the second embodiment, before the capacitor mounting process, the resin layers 8-1 and 8-2 are separated from the base 6 to form a separation surface. That is, the capacitor 2 of the second embodiment has the above-mentioned contact surface, separation surface, separation surface, or a plurality of these surfaces before the capacitor mounting process. The capacitor 2 of the second embodiment is the same as the capacitor 2 after the mounting process of the first embodiment, and its description is omitted.

[0079] The separation surface is formed, for example, when the resin layers 8-1 and 8-2 (i.e., liquid resin) before curing are cured (curing process). For example, the resin shrinks during the curing process and separates from the base 6, thereby forming the separation surface. The amount of shrinkage of the resin during curing can be adjusted, for example, according to changes in shrinkage factors such as the type of resin, the internal pressure of the resin before curing, and the curing conditions. The separation surface of the second embodiment can also be formed by a heating process different from the installation process and the curing process. The formation period of the separation surface is not limited to the installation process or the curing process.

[0080] According to the second embodiment, the following operations or effects can be obtained.

[0081] (1) The action or effect described in the first embodiment can be obtained.

[0082] (2) Since capacitor 2 has a contact surface, a separation surface, a separation surface, or a plurality of these surfaces regardless of the capacitor mounting process, the function or effect described in the first embodiment can be obtained by capacitor 2 before being mounted on a wiring board.

[0083] Regarding the above-mentioned embodiment, characteristic matters, advantages, modifications, etc. are listed below.

[0084] (1) In the above embodiment, the adhesive force of the resin layers 8-1 and 8-2 to the base 6 and the adhesive force of the resin layers 8-1 and 8-2 to the sealing member 14 are adjusted by the combination of materials. However, for example, the surface of the base 6 or the sealing member 14 may be treated with a surface treatment agent such as a primer, a fluorine-based coating agent, or a silicone-based coating agent to increase or decrease their adhesive force. The surface treatment agent can, for example, expand the range of adjustment of the adhesive force, thereby reducing the burden of forming the contact surface, the separation surface, the separation surface, or these multiple surfaces.

[0085] (2) Figure 3 In the illustrated separation plane of the capacitor 2, for the sake of convenience of illustration, the resin layers 8-1 and 8-2 are clearly separated from the base 6. However, the separation plane may form a small gap through which the gaseous electrolyte can pass.

[0086] (3) Figure 5 As shown, the capacitor 2 may include a resin layer 8-3 in addition to the resin layers 8-1 and 8-2. The resin layer 8-3 is disposed between the peripheral wall 22 of the base 6 and the side surface of the outer casing 10. The resin layer 8-3 suppresses the gap between the peripheral wall 22 and the outer casing 10, restricts the relative movement of the capacitor body 4 and the base 6, and thus improves the vibration resistance of the capacitor 2.

[0087] The resin layer 8-3 is opposite to the peripheral wall 22 of the base 6 via the boundary portion 15-4. The boundary portion 15-4 is formed by the opposing surface on the resin layer 8-3 side and the opposing surface on the base 6 side. The adhesive force of the resin layer 8-3 relative to the base 6 is the same as the adhesive force of the resin layers 8-1 and 8-2 relative to the base 6 described in the first embodiment. The boundary portion 15-4 can be a contact surface, a separation surface, a bonding surface, a separation surface, or multiple surfaces among these surfaces. Between the supporting protrusions 26-1 and 26-2, the capacitor body 4 is separated from the base 6, so the boundary portion 15-1 is connected to the boundary portion 15-4. The gas flowing in the boundary portion 15-1 can be discharged to the outside of the capacitor through the gap between the open end of the outer casing 10 and the base 6 and the boundary portion 15-4.

[0088] (4) The protrusion 20 is not limited to the above-mentioned shape as long as it surrounds the insertion holes 18-1 and 18-2, and can be changed as appropriate. For example, the base 6 can also have two protrusions, and the two protrusions surround the insertion holes 18-1 and 18-2 respectively. In addition, the grooves 48 and 50 can also be provided as needed.

[0089] (5) In the above embodiment, the resin injection hole 30 is formed in the base 6, and the resin is injected after the base 6 is set on the capacitor body 4 to form the resin layers 8-1 and 8-2, but it can also be changed appropriately. It is also possible to make the resin adhere to the capacitor body 4 or the base 6, and then install the base 6 on the sealing member 14 side of the capacitor body 4, and make the resin spread between the capacitor body 4 and the base 6, so that the gap between the capacitor body 4 and the base 6 is filled with resin. The resin that fills the gap between the capacitor body 4 and the base 6 forms the resin layer 8-1. According to this structure, it is not necessary to provide the resin injection hole 30.

[0090] (6) The height of the protrusion 20 may be lower than the height difference H or higher than the height difference H. The protrusion 20 that is lower than the height difference H can suppress the resin forming the resin layer 8-1 from invading the through-insertion holes 18-1 and 18-2. In addition, a gap is formed between the protrusion 20 and the sealing member 14, and a flow path of air and resin toward the through-insertion holes 18-1 and 18-2 of the base 6 can be formed through the gap. When a gap remains between the protrusion 20 and the sealing member 14 and the gap is connected to the boundary portions 15-1 and 15-2, the gas in the gap can be discharged to the outside of the capacitor 2 through the boundary portions 15-1 and 15-2.

[0091] The protrusion 20 higher than the height difference H contacts the sealing member 14, and can suppress the resin injected between the base 6 and the sealing member 14 from invading the insertion holes 18-1 and 18-2 at a high level. A gap is formed between the open end of the outer case 10 and the base 6, and an air flow path can be formed through the gap.

[0092] As described above, the most preferred embodiments of the present disclosure have been described, but the technology of the present disclosure is not limited to the above description. A person skilled in the art can certainly make various modifications and changes based on the gist of the invention described in the claims or disclosed in the specification, and these modifications and changes are certainly included in the scope of the present disclosure.

[0093] Industrial Applicability

[0094] The technology disclosed herein can be widely used in electronic devices and is useful.

[0095] Description of symbols

[0096] 2: capacitor; 4: capacitor body; 6: base; 8-1, 8-2, 8-3: resin layer; 10: outer casing; 12: capacitor element; 14: sealing member; 15-1, 15-2, 15-3, 15-4, 54: boundary portion; 16-1, 16-2: terminal lead; 18-1, 18-2: insertion hole; 20: protrusion; 22: peripheral wall; 24-1, 24-2: guide groove; 26-1, 26-2: supporting protrusion; 30: resin injection hole; 32: through hole; 34: shielding portion; 36, 38: step portion; 40: supporting portion; 44: retreat portion; 46: flat portion; 48, 50: groove portion; 52-1, 52-2: gas passage; 54: boundary portion.

Claims

1. A capacitor, characterized in that: The capacitor has: A capacitor body, comprising an outer casing, a sealing member mounted on an opening of the outer casing, and a terminal lead penetrating the sealing member; a base, which is provided on the sealing member side of the capacitor body and has a through-hole through which the terminal lead is inserted and exposed to the mounting surface side and a protrusion surrounding the through-hole; as well as a resin layer disposed at least between the base and the sealing member, The base and the resin layer are separated or contacted without adhesion at least in part, or the adhesive force of the resin layer with respect to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the mounting process, The boundary portion between the base and the resin layer includes a contact surface, a separation surface, or a contact surface and a separation surface between the base and the resin layer, and a gas passage for gas to pass through is formed by the boundary portion.

2. The capacitor according to claim 1, characterized in that The adhesive force of the resin layer to the base is at least partially smaller than the adhesive force of the resin layer to the sealing member.

3. The capacitor according to claim 1 or 2, characterized in that: A boundary portion between the protruding portion and the sealing member communicates with the outside of the capacitor through the gas passage.

4. The capacitor according to claim 1 or 2, characterized in that: The resin layer is also arranged inside the insertion hole.

5. The capacitor according to claim 1 or 2, characterized in that: The base further includes a peripheral wall disposed on the outer side of the outer shell. The resin layer is further disposed between the peripheral wall and the outer casing.

6. A method for manufacturing a capacitor, characterized in that: The manufacturing method of the capacitor has the following steps: Manufacturing a capacitor body including an outer casing, a sealing member mounted on an opening of the outer casing, and a terminal lead penetrating the sealing member; Making a base having a through-hole and a protrusion surrounding the through-hole; The base is arranged on the sealing member side of the capacitor body, and the terminal lead is inserted through the insertion hole to be exposed to the mounting surface side; as well as forming a resin layer between the base and the sealing member, The base and the resin layer are separated or contacted without adhesion at least in part, or the adhesive force of the resin layer with respect to the base is smaller than the force generated between the base and the resin layer due to thermal deformation during the mounting process, The boundary portion between the base and the resin layer includes a contact surface, a separation surface, or a contact surface and a separation surface between the base and the resin layer, and a gas passage for gas to pass through is formed by the boundary portion.

7. A method for installing a capacitor, characterized in that: The capacitor installation method includes the following steps: A mounting step of mounting the capacitor according to any one of claims 1 to 5 on a circuit board by means of solder; and The reflow process is to heat-treat the solder so as to bond the circuit board and the capacitor. The base and the resin layer are separated by the heat treatment, and the gas passage is formed.

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