Patent Application
20250218696
This application claims the benefit of priority from Chinese Patent Application No. 202411623591.8, filed on Nov. 14, 2024. The content of the aforementioned application, including any intervening amendments thereto, is incorporated herein by reference in its entirety.
This application relates to aluminum electrolytic capacitors, and more particularly to an ultra-thin solid aluminum electrolytic capacitor.
Solid aluminum electrolytic capacitors have been extensively used in electronic products. In order to conform to the trend of thinning electronic products and components, capacitors are required to be more and more thin. Though traditional solid aluminum electrolytic capacitors have been improved and upgraded to some extents in the structure and manufacturing process, there are still several technical bottlenecks in the thinning and miniaturization design of capacitors. At present, the surface-mount solid aluminum electrolytic capacitors are mainly fabricated by attaching a base to an encapsulated capacitor body, and bending the leads. The assembly of the traditional solid aluminum electrolytic capacitors, which involves mounting the rubber cover before mounting the base, has some shortcomings. For example, in the current fabrication method, the rubber cover is sleeved on the element, and then compressed and sealed with the shell opening, so the product height is greatly dependent on the thickness of the butyl rubber cover. To meet the airtightness, heat-resistant and shock-resistant requirements and prevent the product defects caused by moisture and gas expansion, the thickness of the rubber cover should be 1.5 mm or more, which restricts the minimum height limit of the solid aluminum electrolytic capacitors. The minimum height of the existing solid aluminum electrolytic capacitors is 4.2, which still cannot be applied in some scenarios. Breaking through the thickness limitation has become a major challenge in the industry.
In view of the deficiencies in the prior art, this application provides an ultra-thin solid aluminum electrolytic capacitor, where the cover body and the shell opening are integrally assembled by injection molding, such that the cover can still meet the requirements for heat resistance and shock resistance even with a reduced thickness. This design breaks through the thickness limitation of the product while maintaining strong heat resistance and shock resistance, arriving at an ultra-thin design of the solid aluminum electrolytic capacitor.
Technical solutions of this application are described as follows.
This application provides an ultra-thin solid aluminum electrolytic capacitor, comprising:
wherein a side of the case is provided with an opening; a flanged clamping portion is provided at the opening; and the cover is embedded inside the opening through injection molding to encapsulate the element in the case;
the cover comprises a base plate, an inner plug, and a sealing side wall; the sealing side wall and the inner plug are vertically provided at an upper end face of the base plate; the inner plug is located at an inner side of the sealing side wall; a groove is provided between the inner plug and the sealing side wall; the groove is abutted against a part of the case in the groove; an end face of the inner plug is symmetrically provided with two lead holes running through the cover; and each of the two lead holes is provided with a lead wire as an electrode terminal.
In an embodiment, the cover is formed by filling a cavity between the opening of the case and the element with a molten plastic, and solidification.
In an embodiment, an outer edge of an upper end of the inner plug is provided with a flange structure protruding outwardly; and a diameter of an outer ring of the flange structure is larger than a diameter of an outer ring of the inner plug.
In an embodiment, a side wall of the flange structure is circumferentially provided with a concave surface; and the concave surface is configured to fit an inner wall of an annular concave portion in the case.
In an embodiment, an inner wall of an end of the sealing side wall away from the base plate is provided with a protruding portion; and the protruding portion is configured to fit an outer wall of an annular concave portion in the case.
In an embodiment, the groove comprises a vertical groove portion and a horizontal groove portion; the vertical groove portion is intersected and communicated with the horizontal groove portion to form an L-shaped configuration; the vertical groove portion is embedded in a side wall of the case; and the horizontal groove portion is embedded in the flanged clamping portion.
In an embodiment, two lead slots are provided at an outer side of a bottom of the base plate; first ends of the two lead slots are communicated with the two lead holes, respectively; and second ends of the two lead slots are configured to extend to a side wall of the base plate, wherein the second ends are ends of the two lead slots away from the two lead holes, respectively.
In an embodiment, a first spacer is provided between the end face of the inner plug and the element; and a second spacer is provided between an end face of the element and a top surface of an inner cavity of the case.
In an embodiment, an end of the sealing side wall away from the base plate is configured to extend to form a clamping wall; and an inner side of the clamping wall is configured to fit an outer wall of the case.
In an embodiment, the lead wire comprises a first portion, a second portion, a third portion and a fourth portion; the first portion has a sheet-shaped structure; a first end of the first portion is connected to the element; a second end of the first portion is connected to a first end of the second portion; a second end of the second portion is weldedly connected to a first end of the third portion; a second end of the third portion is connected to an end of the fourth portion; the third portion and the fourth portion both have a flat structure; and the third portion and the fourth portion are configured to together form a L-shaped structure.
Compared with the prior art, this application has the following advantages.
The ultra-thin solid aluminum electrolytic capacitor provided in this application can solve the problem in the prior art that the solid aluminum electrolytic capacitor needs to be connected to the base seat, resulting in an increase in the total height of the product and cannot be thinned.
In this application, the cover is molded with the opening of the case into the whole structure by injection molding. The cover in the case of reducing the thickness can still meet the heat resistance and shock resistance requirements. The solid aluminum electrolytic capacitor with the cover breaks through the limit thinness of the product, and still has strong heat resistance and shock resistance, to achieve the ultra-thinning of solid aluminum electrolytic capacitors. Based on the cover designed herein, the longitudinal length difference between the aluminum foil and the electrolytic paper in the element can be reduced to 0.5 mm. The lead wire can be designed to a flattened structure with the simple “B” part (without aluminum post), making the lead wire miniaturized. The total height of the entire solid aluminum electrolytic capacitor can be controlled to less than 3.0 mm, which breaks through the size limit of the current products without weakening heat resistance, shock resistance and air tightness, realizing the thinned design. The electrolytic capacitor not only meets the size requirements for thinner design of electronic products, but also improves the sealing effect, reflow soldering thermal stress, and shock resistance, and replaces the traditional encapsulation method of first encapsulating the rubber cover and then attaching the vibration-resistant base seat to the outer side. The service life of solid aluminum electrolytic capacitor is prolonged. Moreover, the manufacturing process of the solid aluminum electrolytic capacitor is simple, easy to operate, low cost, and can meet the needs of the production field. The cover structure provided herein can expand the application ranges of surface-mount solid aluminum electrolytic capacitors, solid-liquid hybrid aluminum electrolytic capacitors, and liquid aluminum electrolytic capacitors.
In order to illustrate the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the drawings required in the description of the embodiments or the prior art will be briefly described below. Obviously, presented in the drawings are merely some embodiments of the present disclosure, which are not intended to limit the disclosure. For those skilled in the art, other drawings may also be obtained according to the drawings provided herein without paying creative efforts.
In the drawings: 1, case; 2, element; 3, lead wire; 4, cover; 5, first spacer; 6, second spacer; 101, opening; 102, flanged clamping portion; 103, annular concave portion; 301, first portion; 302, second portion; 303, fourth portion; 304, third portion; 401, base plate; 402, inner plug; 403, sealing side wall; 404, groove; 405, lead hole; 4011, lead slot; 4012, chamfer; 4021, flange structure; 4022, concave surface; 4031, protruding portion; 4032, clamping wall; 4041, vertical groove portion; and 4042, horizontal groove portion.
The technical solutions of the disclosure will be described in detail below in combination with the drawings in the embodiments. Obviously, described below are merely some embodiments of the disclosure, which are not intended to limit the disclosure. The following detailed description is merely illustrative, and is not intended to limit the scope of the disclosure. For those skilled in the art, other embodiments obtained based on these embodiments without paying creative efforts should fall within the scope of the disclosure defined by the appended claims.
As used herein, it should be noted that the orientation or positional relationship indicated by the terms such as “upper”, “lower”, “bottom”, “inside”, “outside” is based on the orientation or positional relationship shown in the accompanying drawings, which are only for the convenience of describing the technical solutions and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed or operated in a specific orientation. Therefore, these terms should not be understood as a limitation of the present disclosure. Moreover, “A part” and “B part” are often used in the related field to indicate structural parts of lead wires, which are only for the convenience of describing the technical solutions and simplifying the description.
An ultra-thin wound solid aluminum electrolytic capacitor is prepared as follows.
An anode aluminum foil, a cathode aluminum foil, and an electrolytic paper with a preset size are prepared by cutting. The anode aluminum foil and the cathode aluminum foil are nailed with the lead wires 3, respectively. The anode aluminum foil, the electrolytic paper, and the cathode aluminum foil are sequentially stacked, and then wound to obtain the element 2.
As shown in
Specifically, the solid aluminum electrolytic capacitor is composed of the case 1, the element 2, the lead wire 3, and the cover 4. The cover 4 hermetically encapsulates the element 2 inside the case 1, blocks external water vapor from entering the element 2, and maintains a dry state of the inner cavity of the case 1 and the element 2. Thus, the conductive polymer in the element 2 is prevented from reacting with water vapor and failing. The opening 101 of the case 1 is filled to form the cover 4 injection molding, so that the inner cavity of the case 1 forms the sealing cavity. The groove 404 is combined with the case 1. Specifically, the inner plug 402 of the cover 4 is closely combined with the inner wall of the opening 101 of the case 1 and the outer wall of the flanged clamping portion 102, thereby sealing the inner side of the opening 101. Moreover, the sealing side wall 403 of the cover 4 is closely combined with the outer wall of the case 1, thereby sealing the outer side of the opening 101, so as to improve the sealing effect from the inside and outside, respectively. Meanwhile, the combination of the flanged clamping portion 102 and the cover 4 makes the solid aluminum electrolytic capacitor not deformed under high temperature and vibration environment, prevents the cover 4 from deformation and movement outward under high temperature or high pressure, and improves high temperature resistance and shock resistance.
The upper end face of the base plate 401 is connected to the lower end face of the inner plug 402 and the lower end face of the sealing side wall 403, respectively, so that the base plate 401, the inner plug 402, the sealing side wall 403 form an integrated structure. On the one hand, such an integrated structure improves the sealing property and rigidity, and in the high temperature of reflow soldering, even if the thickness of the base plate 401 is reduced to 0.3 mm or less, the base plate 401 will not produce deformation. On the other hand, the base plate 401, the inner plug 402, the sealing side wall 403 are integrated in the integrative molding way, the base plate 401 increases the support force to protect the lead wire 3, and the integrated structure of the base plate 401 and the inner plug 402 improves the sealing effect, heat-resistant effect, and shock-resistant effect, so that the cover 4 at the same time has heat-resistant and shock-resistant performances. Thus, the cover 4 has both heat-resistant and shock-resistant performances without the need for additional shock-resistant bases. Through the injection molding of the cover 4 and the opening 101 of the case 1, the cover 4 can still meet the requirements of heat resistance and firmness even with a reduced thickness. The inner plug 402 and the sealing side wall 403 are arranged coaxially. In this embodiment, preferably, the inner plug 402 is a cylindrical structure, the cross section of the sealing side wall 403 is a ring-shaped structure, and the axes of the inner plug 402 and the sealing side wall 403 coincide. In another embodiment, the cross section of the inner plug 402 and the sealing side wall 403 may also be polygonal. The total height of the entire solid aluminum electrolytic capacitor can be controlled to be 3.0 mm or less, which breaks through the minimum height limitation of the current product, and enables the cover to be applied to the solid aluminum electrolytic capacitor while maintaining heat resistance and shock resistance. The height of the solid aluminum electrolytic capacitor with the cover 4 can be greatly reduced while maintaining good sealing, heat resistance, and shock resistance, thus realizing the thin design of the product.
The cover 4 is formed by filling a cavity between the opening 101 of the case 1 and the element 2 with a molten plastic and solidification, so that the molten plastic is tightly bonded to the inner and outer parts in the opening 101.
Specifically, after the case 1 is assembled with the element 2, the case 1 with the element 2 is placed in the injection mold. When the molten plastic reaches a predetermined temperature and pressure, the screw rod or the plunger of the injection molding machine injects molten plastic into the cavity between the outer side of the opening 101 and the injection mold through the nozzle, and the sealing side wall 403 is formed after injection. The cavity between the inner side of the opening 101 and the flanged clamping portion 102 and the element 2 is injected with molten plastic to form the base plate 401 and the inner plug 402, after cooling, thereby obtaining the integrated cover 4, the plastic is tightly combined with the inner and outer parts in the opening 101. The cover 4, the case 1, and the opening 101 are integrally assembled by injection molding. The cover 4 hermetically seals the element 2 inside the case 1 to obtain the thin solid aluminum electrolytic capacitor.
The outer edge of the upper end of the inner plug 402 is provided with a flange structure 4021 protruding outwardly. The diameter of an outer ring of the flange structure 4021 is larger than the diameter of an outer ring of the inner plug 402. Specifically, after the injection molding is completed, the inner plug 402 is formed inside the opening 101. In this embodiment, the case 1 is cylindrical, so the inner plug 402 is a cylindrical body, which is closely fitted with the inner wall of the case 1. In other embodiments, the cross-sectional shape of the case 1 may be rectangular or triangular, and the cross-sectional shape of the inner plug 402 is also rectangular or triangular. In addition, in this embodiment, the flanged clamping portion 102 at the opening 101 is folded inwardly, in other embodiments, the flanged clamping portion 102 can be set to fold outwardly, which can also clamp the cover 4 to improve heat resistance and firmness.
The outer edge of the upper end of the inner plug 402 is provided with the flange structure 4021 protruding outwardly. The diameter of the outer ring of the flange structure 4021 is larger than that of the outer ring of the inner plug 402. The peripheral sidewall of the flange structure 4021 and the lower end surface of the flange structure 4021 form the step structure. The step structure fits with the flanged clamping portion 102 to improve stability, heat resistance and sealing performances, and in addition to prevent the cover 4 from moving when the air pressure expands under high temperature. The outer peripheral side of the flange structure 4021 closely fits to the inner peripheral wall of the case 1, and the lower end surface of the flange structure 4021 closely fits to the upper end surface of the flanged clamping portion 102 at the opening 101, improving the sealing effect.
The groove 404 includes a vertical groove portion 4041 and a horizontal groove portion 4042. The vertical groove portion 4041 is intersected and communicated with the horizontal groove portion 4042 to form an L-shaped configuration. The vertical groove portion 4041 is embedded in the side wall of the case 1. The horizontal groove portion 4042 is embedded in the flanged clamping portion 102 at the opening 101.
Specifically, referring to
Referring to
Specifically, in the processing of the lead wire 3, the first portion 301 is formed by flattening the aluminum column. The lower end of the first portion 301 is welded together with the fourth portion 303 through the second portion 302 to shorten the longitudinal length of the lead wire 3. The fourth portion 303 has a flat structure that can reduce the longitudinal height of the lead wire 3. The lead wire 3 is designed to match and combine with the cover 4 to reduce the longitudinal height of the lead wire 3 and the cover 4. In addition, the lead wire 3 is preset with the third portion 304, so that the lead wire 3 does not need to be bent again after injection molding of the cover 4, avoiding the damage caused by the secondary bending to the body structure of the thinned solid aluminum electrolytic capacitor. Therefore, the structural design of the lead wire 3 of the present disclosure provides the necessary conditions for the thinning of the product.
The end face of the inner plug 402 is symmetrically provided with two lead holes 405 running through the cover 4. Each of the lead holes 405 are penetrated with the lead wire 3 as an external electrode terminal. Two lead slots 4011 are provided at the outer side of the bottom surface of the base plate 401. Ends of the two lead slots 4011 are communicated with the two lead holes 405, respectively, and the other ends of the two lead slots 4011 away from the two lead holes 405 extends to the side wall of the base plate 401.
The element 2 is formed by stacking the anode aluminum foil, the electrolytic paper, and the cathode aluminum foil, and then winding the combination of the anode aluminum foil, the electrolytic paper, and the cathode aluminum foil. The lead wire 3 is divided into an anode lead wire and a cathode lead wire. The anode aluminum foil is connected to the anode lead wire, and the cathode aluminum foil is connected to the cathode lead wire. During the injection molding of the cover 4, the lead wire 3 is pre-buried in the cover 4. After injection molding, the lead wire 3 runs between the inner plug 402 and the base plate 401, the anode and cathode lead wires 3 penetrate out of the base plate 401, and are bent at one end of the anode and cathode lead wires 3 and affixed to the lead slots 4011, respectively. The lead wire 3 is extended along the lead slot 4011 to expose the sidewall of the base plate 401. The parts of the anode and cathode lead wires exposed to the base plate 401 are soldered and fixed to the PCB. The lead wire 3 leads out externally from the element 2 and passes through the inner plug 402 and the base plate 401 and are directly welded and fixed to the PCB board. Since the inner plug 402 and the base plate 401 are integrally molded, and have both heat resistance and shock resistance, there is no need to additionally connect the base to satisfy the conditions of heat resistance and shock resistance of the surface-mount solid aluminum electrolytic capacitor. Therefore, the total height of the cover 4 can be greatly reduced while the cover 4 has good sealing performance, heat resistance and shock resistance, instead of the traditional combination design of the butyl rubber plug and the base. When the design of the cover 4 is applied to the solid aluminum electrolytic capacitor, the longitudinal length difference between the aluminum foil and the electrolytic paper can be reduced to 0.5 mm, which can further reduce the total height of the solid aluminum electrolytic capacitor, and the cutting width of the aluminum foil can be set to 1.6 mm or less. The electrolytic paper and the aluminum foil are stacked alternately, and then wound to form the cylindrical element. The “longitudinal length difference” refers to the length difference of the electrolytic paper and the aluminum foil in the longitudinal direction of the element. The longitudinal length of the electrolytic paper is designed to be longer than that of the aluminum foil to prevent the aluminum foil from being exposed in the longitudinal direction after winding. At the same time, since the base plate 401, the inner plug 402, and the sealing side wall 403 of the cover 4 are integrally molded, based on the structure of the cover 4, the total thickness of the inner plug 402 can be reduced to 1.3 mm or less, and the thickness of the base plate 401 can be reduced to 0.3 mm or less. The total height of the assembled wound solid aluminum electrolytic capacitor can be controlled to be 3.0 mm or less, which breaks through the size limitation, and the product can still resist the impact of gas expansion after reflow soldering at high temperature, and still maintains the heat resistance and shock resistance.
The ultra-thin wound solid aluminum electrolytic capacitor is prepared as follows.
The anode aluminum foil, the cathode aluminum foil, and the electrolytic paper with a preset size are prepared by cutting. The anode aluminum foil and the cathode aluminum foil are nailed with the lead wire 3, respectively. The anode aluminum foil, the electrolytic paper, and the cathode aluminum foil are sequentially stacked, and then wound to obtain the element 2.
Referring to
Further, the case 1 is provided with the inwardly contracting annular concave portion 103 near the opening 101. The annular concave portion 103 is formed by machining with the girdle wheel prior to molding the injection-molded cover 4. The inner wall of the annular concave portion 103 is a convex surface, and the outer wall of the annular concave portion 103 is a concave surface. During injection molding, the inner wall of the annular concave portion 103 immersed by molten plastic is a convex surface. After cooling, the concave surface 4022 is circumferentially formed on the side wall of the flange structure 4021. The presence of the concave surface 4022 further extends the entering path of water vapor and strengthens the sealing between the outer peripheral wall of the flange structure 4021 and the inner wall of the case 1. The concave surface 4022 is combined with the inner wall of the annular concave portion 103 of the case 1, further improving the structural stability.
The inner wall of the end of the sealing side wall 403 away from the base plate 401 is provided with a protruding portion 4031. The protruding portion 4031 is affixed to/abuts against the outer wall of the annular concave portion 103 in the case 1. Specifically, the sealing side wall 403 is a structural body formed by injection molding in the cavity between the injection mold and the outer wall of the case 1. During injection molding, the concave surface of the outer wall of the annular concave portion 103 is immersed with molten plastic, which forms the protruding portion 4031 on the inner wall of the sealing side wall 403 after cooling. The presence of the protruding portion 4031 further prolongs the entry path of the water vapor, and strengthens the sealing and shock resistance of the inner peripheral wall of the sealing side wall 403 and the outer peripheral wall of the case 1. The protruding portion 4031 is matched with the concave surface of the outer wall of the annular concave portion 103 of the case 1, which further improves structural stability.
The ultra-thin wound solid aluminum electrolytic capacitor is prepared as follows.
The anode aluminum foil, the cathode aluminum foil, and the electrolytic paper with a preset size are prepared by cutting. The anode aluminum foil and the cathode aluminum foil are nailed with the lead wire, 3 respectively. The anode aluminum foil, the electrolytic paper, and the cathode aluminum foil are sequentially stacked, and then wound to obtain the element 2.
Referring to
The sealing side wall 403 and the clamping wall 4032 are molded by injection molding. The inner peripheral wall of the clamping wall 4032 closely fits with the outer peripheral wall of the case 1. The total height of the sealing side wall 403 and the clamping wall 4032 is more than one-half of the longitudinal height of the case 1. In such an arrangement, on the one hand, the entry path for water vapor is prolonged, and at the same time the sealing effect is improved. On the other hand, the combination of the sealing side wall 403 and the clamping wall 4032 increases the force area, improves resistance to thermal and mechanical stress in high-temperature reflow soldering, and improves the effect of shock resistance.
As shown in
As shown in
The first spacer 5 is placed at the end face of the element 2 before injection molding. The lead wire 3 passes through the first spacer 5, and the first spacer 5 blocks the molten plastic during injection molding, thereby preventing the molten plastic to flow into the interior of the element 2, and playing a role in blocking and insulating action, and avoiding the plastic penetration between the anode aluminum foil, the cathode aluminum foil, the electrode paper, and the conductive polymer inside the element 2.
The second spacer 6 is provided between the end surface of the element 2 and the top surface of the inner cavity of the case 1. Since the foil-paper matching gap between the aluminum foil and the electrolytic paper is narrowed to 0.5 mm, the end of the anode aluminum foil is close to the inner wall of the case 1, the second spacer 6 is arranged to prevent short circuit between the end of the anode aluminum foil and the inner wall of the case 1, which improves the safety. In this embodiment, the first spacer 5 and the second spacer 6 may be insulating material with the thickness of 0.03-0.04 mm. In another embodiment, the first spacer 5 and the second spacer 6 can be made of insulating thermal conductive material, which may further improve heat resistance and heat dissipation.
Described above are merely preferred embodiments of the disclosure, which are not intended to limit the disclosure. It should be understood that any modifications and replacements made by those skilled in the art without departing from the spirit of the disclosure should fall within the scope of the disclosure defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202411623591.8 | Nov 2024 | CN | national |
