A surface-mount solid aluminum electrolytic capacitor and its preparation method

Abstract

This invention discloses a surface-mount solid aluminum electrolytic capacitor and its manufacturing method, comprising a capacitor core package, which includes N capacitor cores, N+1 conductive metal meshes, a substrate, anode leads, cathode leads, and a silver paste covering tape. The capacitor core package is encapsulated and electroplated to form a solid aluminum electrolytic capacitor. The capacitor core includes an anode portion, a cathode portion, and an insulating barrier tape. In this invention, the conductive metal mesh sandwiched between the metal pads in the anode portion of the capacitor core and the cathode portion of the capacitor core can achieve the flatness of the core package. The silver paste covering tape located on the side of the cathode portion of the core package is embedded in the gap formed between two adjacent capacitor cores due to the conductive metal mesh sandwiched, forming an integrated connection. This prevents the resin encapsulant from being squeezed into the core layers during encapsulation, preventing core deformation damage that could lead to increased leakage current and increased ESR. Furthermore, it can prevent insufficient capacitance or even capacitor failure caused by delamination between cores.

Description

Technical Field

[0001] This invention relates to the field of solid aluminum electrolytic capacitor technology, specifically to a surface-mount solid aluminum electrolytic capacitor and its preparation method. Background Technology

[0002] Currently, surface-mount solid aluminum electrolytic capacitors are mainly divided into two categories based on their core structure: wound solid aluminum electrolytic capacitors and multilayer solid aluminum electrolytic capacitors. Wound solid aluminum electrolytic capacitors, due to their core structure and assembly method, are relatively large and thick, failing to meet the miniaturization and thinning requirements of the current electronics and information industry. Multilayer solid aluminum electrolytic capacitors, using high-conductivity polymers as the solid electrolyte and encapsulated in epoxy resin, solve the problems of large size and thickness associated with wound solid aluminum electrolytic capacitors while maintaining excellent frequency impedance and temperature characteristics.

[0003] The basic manufacturing process of multilayer solid aluminum electrolytic capacitors involves cutting electrolytic foil into strips, using barrier adhesive to divide the foil into anode and cathode regions, forming a conductive polymer solid electrolyte layer on the cathode region surface, and then sequentially covering the conductive polymer solid electrolyte layer with a conductive carbon paste layer and a silver paste layer to form a capacitor unit / core. Multiple capacitor units / cores are stacked in parallel on the upper and lower surfaces of an external lead frame made of metal strip, with the anode and cathode led out respectively. Then, they are encapsulated with epoxy resin, and finally, the leads exposed outside the resin shell are bent into shape to form external terminals.

[0004] 1) In the existing technology, the general design involves stacking cores sequentially on both sides of a metal strip. The anode and cathode leads are led out from the middle of the anode and cathode of the core package, respectively. The anode portions (formed foil) of multiple cores are welded to the anode tongue of the external lead frame. The cathode portions of multiple cores are bonded in parallel with conductive silver paste and then bonded to the cathode tongue of the external lead frame with conductive silver paste. The cathode portion of a single core is thicker than the anode portion because it is covered with a conductive polymer solid electrolyte layer, a conductive carbon paste layer, and a conductive silver paste layer layer. Under the existing manufacturing process, after multiple cores are stacked, the core package presents a wedge-shaped structure with a thin anode and a thick cathode, and there are gaps at the edges of the cathode portions of adjacent cores. During the injection molding process of the encapsulation process, the resin encapsulant is easily squeezed into the gaps between the cathode portions of the core, which increases the core stress, makes the core easy to deform, causes insufficient capacity, and increases leakage current and equivalent series resistance (ESR), which can lead to capacitor failure in severe cases.

[0005] 2) In existing technologies, during the formation of external terminals, when the leads exposed outside the resin casing are bent and shaped, the mechanical force impacts the junction between the resin casing and the lead outlet, creating gaps and compromising the airtightness of the casing. This allows external moisture to easily penetrate, reducing the capacitor's moisture resistance. Simultaneously, it also causes mechanical impact on the core, leading to increased leakage current and affecting capacitor yield. Therefore, this invention designs a surface-mount solid aluminum electrolytic capacitor and its fabrication method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a surface-mount solid aluminum electrolytic capacitor and its preparation method to solve the above-mentioned technical problems.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a surface-mount solid aluminum electrolytic capacitor, comprising a capacitor core package, wherein the capacitor core package is encapsulated and electroplated to form a solid aluminum electrolytic capacitor;

[0008] The capacitor core package includes N capacitor cores, N+1 conductive metal meshes, a substrate, anode leads, cathode leads, and a silver paste covering strip;

[0009] The capacitor core includes an anode portion, a cathode portion, and an insulating barrier tape. The anode portion includes an anode area of ​​a fifth aluminum foil and a metal gasket, with one side of the anode area of ​​the fifth aluminum foil laid flat and electrically connected to the metal gasket. The metal gasket includes a rectangular main body portion, with two rectangular protrusions on one long side of the rectangular main body portion, and the rectangular protrusions are disposed away from the insulating barrier tape. The cathode portion includes a cathode area of ​​the fifth aluminum foil, which includes a cathode area of ​​a second aluminum foil, a conductive polymer layer, and a conductive carbon paste layer. The insulating barrier tape separates the anode portion and the cathode portion.

[0010] The N+1 conductive metal meshes are stacked sequentially with N capacitor cores. The conductive metal meshes are located on the cathode portion of the capacitor cores, and the side of the capacitor cores with metal pads faces the substrate. The anode and cathode leads are respectively inserted and fixed to both ends of the substrate. The bottommost conductive metal mesh is in contact with the cathode lead, and the bottommost metal pad is in contact with the anode lead. The rectangular protrusion of the metal pad is embedded in the anode lead. The silver paste covering strip is located on the three side surfaces of the sandwich stack formed by the cathode portions of the N capacitor cores and the N+1 conductive metal meshes. The silver paste covering strip is embedded between the cathode portions of two adjacent capacitor cores and between the cathode portion of the bottommost capacitor core and the cathode tongue of the cathode lead.

[0011] Preferably, the length of the conductive metal mesh is 80%-90% of the length of the cathode portion of the capacitor core, and the width of the conductive metal mesh is 90%-100% of the width of the cathode portion of the capacitor core.

[0012] Preferably, the conductive metal mesh is made by impregnating a copper wire woven mesh with conductive silver paste and then drying it. The copper wire woven mesh is made of phosphor bronze wire with a wire diameter of 25-35 micrometers and a mesh count of 200-400 mesh.

[0013] Preferably, the substrate includes a rectangular body, two sets of rectangular extensions, and a cathode copper-clad foil. The two sets of rectangular extensions are respectively disposed at the four corners of the rectangular body and form an H shape. The cathode copper-clad foil is laid flat and fixed on one side of the rectangular body. The width of the cathode copper-clad foil is equal to the width of the rectangular body, and the length of the cathode copper-clad foil is 50%-65% of the length of the rectangular body.

[0014] Preferably, the anode pin includes an integrally connected anode horizontal portion, anode vertical portion, and anode terminal portion; the anode horizontal portion and anode terminal portion are respectively vertically arranged on opposite sides of the anode vertical portion, and the anode horizontal portion and anode terminal portion are arranged in the same direction; the two free sides of the anode vertical portion are symmetrically arranged with anode rectangular notches that cooperate with the substrate, and the anode rectangular notches are arranged close to the anode terminal portion; the anode vertical portion is formed by cutting and bending to form two corresponding anode tongues and two anode hollow portions, and the anode tongues and anode hollow portions are rectangular; the anode tongues are in contact with the metal pad located at the bottom, and the rectangular protrusion of the metal pad is embedded in the anode hollow portion.

[0015] Preferably, the cathode pin includes an integrally connected cathode tongue, cathode vertical portion, and cathode terminal portion. The cathode tongue and cathode terminal portion are respectively vertically arranged on opposite sides of the cathode vertical portion, and the cathode tongue and cathode terminal portion are arranged in the same direction. The two free sides of the cathode vertical portion are symmetrically arranged with cathode rectangular notches that cooperate with the substrate, and the cathode rectangular notches are arranged away from the cathode terminal portion. The cathode tongue is in contact with the conductive metal mesh located at the bottom.

[0016] A method for fabricating a surface-mount solid aluminum electrolytic capacitor, the method comprising the following steps:

[0017] S1. Cut the aluminum foil into rectangles to form the first aluminum foil;

[0018] S2. Coat the first aluminum foil with barrier adhesive to prepare an insulating barrier tape, divide the anode area and the cathode area, and obtain the second aluminum foil;

[0019] S3. The dielectric layer on the cathode side of the second aluminum foil is reformed and repaired to obtain the third aluminum foil;

[0020] S4. A conductive polymer layer is formed on the cathode region surface of the third aluminum foil to obtain the fourth aluminum foil;

[0021] S5. The cathode region of the fourth aluminum foil is impregnated with conductive graphite emulsion and then dried to form a conductive carbon paste layer, thus obtaining the fifth aluminum foil.

[0022] S6. Weld a pre-processed metal pad onto one side of the anode region of the fifth aluminum foil to obtain the capacitor core;

[0023] S7. The copper wire mesh cut into rectangles is impregnated with conductive silver paste and then dried to make a conductive metal mesh;

[0024] S8. Assemble the pre-processed cathode pins onto one end of the pre-processed substrate using a mating and plugging method, and then glue and fix them. Finally, glue and fix a conductive metal mesh onto the cathode pins to form a cathode base.

[0025] S9. On the cathode base, N capacitor cores and N conductive metal meshes are stacked alternately to form a sandwich stack. Then, conductive silver paste is applied to the three sides of the sandwich stack and cured to form a silver paste covering strip, so as to lead out the cathode and form a core package semi-finished product.

[0026] S10. Assemble the pre-processed anode pins onto the core package semi-finished product to achieve anode lead-out and form a capacitor core package;

[0027] S11. Encapsulate the capacitor core with epoxy resin encapsulant to form a shell, thus producing a capacitor semi-finished product;

[0028] S12. A tin plating layer is prepared on the exposed surfaces of the anode and cathode terminals of the capacitor semi-finished product by electroplating to form terminals suitable for surface mounting, thereby producing a solid aluminum electrolytic capacitor.

[0029] Preferably, step S8 specifically comprises:

[0030] S81. The metal strip is integrally stamped to form the cathode pin;

[0031] S82. Process the copper-clad insulating laminate into a substrate;

[0032] S83. Apply a metal adhesive to the cathode copper foil on the substrate, and attach and fix the cathode tongue on the cathode pin facing the cathode terminal to the cathode copper foil; at the same time, a set of rectangular extensions on the substrate near the cathode copper foil are fitted with a set of cathode rectangular notches on the cathode pin.

[0033] S84. First, apply conductive silver paste to the side of the cathode tongue that is away from the cathode terminal, then place a conductive metal mesh. After the conductive silver paste has cured, fix the conductive metal mesh to the cathode tongue and form an electrical connection to form a cathode base.

[0034] Preferably, step S9 specifically comprises:

[0035] S91. First, coat the surface of the conductive metal mesh on the cathode base with a layer of conductive graphite emulsion, and then stack a capacitor core so that the conductive metal mesh is in contact with the cathode side of the capacitor core. When stacking, the side of the capacitor core with the metal pad on the anode side faces the cathode base.

[0036] S92. First, apply a layer of conductive graphite emulsion to the cathode surface of the stacked capacitor core, and then stack a conductive metal mesh.

[0037] S93. Repeat steps S91 and S92 in sequence until the number of layers of the capacitor core reaches the designed number of layers. Finally, stack a conductive metal mesh to form a sandwich stack.

[0038] S94. Apply conductive silver paste to the three sides of the sandwich stack to form a silver paste covering strip, so that the cathode part of N capacitor cores, N+1 conductive metal mesh and cathode pins are electrically connected to achieve cathode lead-out and form a core package semi-finished product.

[0039] Preferably, step S10 specifically includes:

[0040] S101. The metal strip is integrally stamped to form the anode pin;

[0041] S102. Fit a set of rectangular extensions on the substrate away from the cathode copper foil in the core package semi-finished product with a set of rectangular anode notches on the anode pin. The anode portions of N capacitor cores are stacked on the anode tongue, and the rectangular protrusions of each capacitor core are embedded in the anode cutout.

[0042] S103. The rectangular protrusion of each capacitor core is fixedly connected to the anode cutout by laser welding, so that the anode part of each capacitor core is electrically connected to the anode pin, realizing the anode lead-out and forming a capacitor core package.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1) In the sandwich structure core package of the present invention, the conductive metal mesh sandwiched between the metal gasket welded to the anode part of the core and the cathode part of the core can achieve the flatness of the core package. The silver paste covering strip located on the side of the cathode part of the core package is embedded in the gap formed by the conductive metal mesh sandwich between two adjacent capacitor cores to form an integrated connection. This prevents the resin encapsulant from being squeezed into the core layers during encapsulation, prevents the core from being deformed and damaged, which would cause an increase in leakage current and ESR. Furthermore, it can prevent insufficient capacity or even capacitor failure caused by delamination between cores.

[0045] 2) A conductive metal mesh with a composite structure of silver paste and copper is used as the interlayer material between the cores. Its internal mesh structure can provide buffering and mechanical support protection for the core package, increase the core package's resistance to mechanical impact, help resist the damage to the core package caused by injection molding during the packaging process, and reduce leakage current. Its external silver paste layer can be connected with the silver paste covering strip on the side of the cathode part of the core package, ensuring the electrical connection effect between the cathode parts of the cores and improving ESR.

[0046] 3) The anode and cathode pins of this invention are pre-formed and then plated with tin after encapsulation, replacing the original pin bending process after encapsulation. This can prevent damage to the junction of the shell and the pin lead-out end caused by external force during pin bending, thus preventing a decrease in airtightness. The pins of this invention adopt a bottom lead-out structure, with only the side for surface mounting exposed, and the rest enclosed in the shell. Compared with the traditional structure where the pins are led out from the middle of the two poles of the core package and then bent twice along the shell, this structure has better airtightness and can more effectively prevent external moisture from entering the core package, thus improving the moisture resistance of the capacitor. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the capacitor core structure in this invention;

[0049] Figure 2 This is a schematic diagram of the structure of the metal gasket in this invention;

[0050] Figure 3 This is a schematic diagram of the substrate structure in this invention;

[0051] Figure 4 This is a schematic diagram of the anode pin structure in this invention;

[0052] Figure 5 This is a schematic diagram of the cathode pin structure in this invention;

[0053] Figure 6 This is a schematic diagram of the connection structure of the anode pin, cathode pin, and substrate in this invention;

[0054] Figure 7 This is a schematic diagram of the core package structure in this invention;

[0055] Figure 8 This is a schematic diagram of the structure of the aluminum electrolytic capacitor of the present invention;

[0056] Figure 9 This is a schematic diagram of the preparation method of the present invention.

[0057] The attached diagram lists the components represented by each number as follows:

[0058] 1. Capacitor core; 11. Capacitor core; 111. Cathode portion; 112. Insulating barrier tape; 113. Anode portion; 1131. Metal gasket; 1132. Anode area of ​​the fifth aluminum foil; 1311a. Rectangular main body portion; 1131b. Rectangular protrusion portion; 12. Conductive metal mesh; 13. Substrate; 131. Rectangular body portion; 132. Rectangular extension portion; 133. Cathode copper foil; 14. Anode pin; 141. Anode horizontal portion; 142. Anode vertical portion; 143. Anode terminal portion; 144. Anode rectangular notch; 145. Anode tongue; 146. Anode hollow portion; 15. Cathode pin; 151. Cathode tongue; 152. Cathode vertical portion; 153. Cathode terminal portion; 154. Cathode rectangular notch; 16. Silver paste covering tape; 2. Solid aluminum electrolytic capacitor. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Please see Figure 1-9 The present invention provides a technical solution: a surface-mount solid aluminum electrolytic capacitor, comprising a capacitor core 1, wherein the capacitor core 1 is encapsulated and electroplated to form a solid aluminum electrolytic capacitor 2;

[0061] The capacitor core package 1 includes N capacitor cores 11, N+1 conductive metal meshes 12, a substrate 13, anode leads 14, cathode leads 15, and a silver paste covering strip 16;

[0062] The capacitor core 11 includes an anode portion 113, a cathode portion 111, and an insulating barrier tape 112. The anode portion 113 includes an anode region 1132 of a fifth aluminum foil and a metal pad 1131. One side of the anode region 1132 of the fifth aluminum foil is laid flat and electrically connected to the metal pad 1131. The metal pad 1131 includes a rectangular main body portion 1131a. Two rectangular protrusions 1131b are provided on one long side of the rectangular main body portion 1131a, and the rectangular protrusions 1131b are disposed away from the insulating barrier tape 112. The cathode portion 111 includes a cathode region of the fifth aluminum foil. The cathode region of the fifth aluminum foil includes a cathode region of the second aluminum foil, a conductive polymer layer, and a conductive carbon paste layer. The insulating barrier tape 112 separates the anode portion 113 and the cathode portion 111.

[0063] N+1 conductive metal meshes 12 and N capacitor cores 11 are stacked sequentially. The conductive metal meshes 12 are disposed on the cathode portion 111 of the capacitor core 11, and the side of the capacitor core 111 with metal pads 1131 is stacked facing the substrate 13. The anode pins 14 and cathode pins 15 are respectively inserted and fixed to both ends of the substrate 13. The bottom conductive metal mesh 12 is in contact with the cathode pin 15, and the bottom metal pad 1131 is in contact with the anode pin 14. The rectangular protrusion 1131b of the metal pad 1131 is embedded in the anode pin 14. The silver paste covering strip 16 is disposed on the three side surfaces of the sandwich stack formed by the cathode portions 111 of the N capacitor cores 11 and the N+1 conductive metal meshes 12, and the silver paste covering strip 16 is embedded between the cathode portions 111 of two adjacent capacitor cores 11 and between the cathode portion 111 of the bottom capacitor core 11 and the cathode tongue 153 of the cathode pin 15.

[0064] Specifically, the length of the conductive metal mesh 12 is 80%-90% of the length of the cathode portion 111 of the capacitor core 11, and the width of the conductive metal mesh 12 is 90%-100% of the width of the cathode portion 111 of the capacitor core 11.

[0065] Specifically, the conductive metal mesh 12 is made by impregnating a copper wire woven mesh with conductive silver paste and then drying it. The copper wire woven mesh is made of phosphor bronze wire with a wire diameter of 25-35 micrometers and a mesh count of 200-400 mesh.

[0066] Specifically, the substrate 13 includes a rectangular body portion 131, two sets of rectangular extension portions 132, and a cathode copper-clad foil 133. The two sets of rectangular extension portions 132 are respectively disposed at the four corners of the rectangular body portion 131 and form an H shape. The cathode copper-clad foil 133 is laid flat and fixedly disposed on one side of the rectangular body portion 131. The width of the cathode copper-clad foil 133 is equal to the width of the rectangular body portion 131, and the length of the cathode copper-clad foil 133 is 50%-65% of the length of the rectangular body portion 131.

[0067] Specifically, the anode pin 14 includes an integrally connected anode horizontal portion 141, an anode vertical portion 142, and an anode terminal portion 143. The anode horizontal portion 141 and the anode terminal portion 143 are respectively vertically arranged on opposite sides of the anode vertical portion 142, and the anode horizontal portion 141 and the anode terminal portion 143 are arranged in the same direction. The two free sides of the anode vertical portion 142 are symmetrically arranged with anode rectangular notches 144 that cooperate with the substrate 13. The anode rectangular notches 144 are located close to the anode terminal portion 143. The anode vertical portion 142 is formed by cutting and bending to form two corresponding anode tongues 145 and two anode hollow portions 146. The anode tongues 145 and the anode hollow portions 146 are rectangular. The anode tongues 145 are in contact with the metal pad 1131 located at the bottom. The rectangular protrusion 1131b of the metal pad 1131 is embedded in the anode hollow portion 146. The anode pin 14 is made of copper or copper alloy.

[0068] Specifically, the cathode pin 15 includes an integrally connected cathode tongue 151, cathode vertical portion 152, and cathode terminal portion 153. The cathode tongue 151 and cathode terminal portion 153 are respectively vertically arranged on opposite sides of the cathode vertical portion 152, and the cathode tongue 151 and cathode terminal portion 153 are arranged in the same direction. The two free sides of the cathode vertical portion 152 are symmetrically arranged with cathode rectangular notches 154 that cooperate with the substrate 13, and the cathode rectangular notches 154 are arranged away from the cathode terminal portion 153. The cathode tongue 151 is in contact with the conductive metal mesh 12 located at the bottom, and the cathode pin 15 is made of copper or copper alloy.

[0069] A method for fabricating a surface-mount solid aluminum electrolytic capacitor, the method comprising the following steps:

[0070] S1. Cut the aluminum foil into rectangles to form the first aluminum foil;

[0071] S2. Coat the first aluminum foil with barrier adhesive to prepare insulating barrier tape 112, divide the anode area and the cathode area, and obtain the second aluminum foil.

[0072] S3. The dielectric layer on the cathode side of the second aluminum foil is reformed and repaired to obtain the third aluminum foil;

[0073] S4. A conductive polymer layer is formed on the cathode region surface of the third aluminum foil to obtain the fourth aluminum foil;

[0074] S5. The cathode region of the fourth aluminum foil is impregnated with conductive graphite emulsion and then dried to form a conductive carbon paste layer, thus obtaining the fifth aluminum foil.

[0075] S6. A pre-processed metal pad 1131 is welded onto one side of the anode region 1132 of the fifth aluminum foil to obtain the capacitor core 11.

[0076] S7. The copper wire mesh cut into rectangles is immersed in conductive silver paste and then dried to make conductive metal mesh 12.

[0077] S8. Assemble the pre-processed cathode pins 15 on one end of the pre-processed substrate 13 in a mating and plugging manner, and then glue and fix them. Then glue and fix a conductive metal mesh 12 on the cathode pins 15 to form a cathode base.

[0078] S9. On the cathode base, N capacitor cores 11 and N conductive metal meshes 12 are stacked alternately to form a sandwich stack. Then, conductive silver paste is applied to the three sides of the sandwich stack and cured to form a silver paste covering strip 16, so as to realize the cathode lead-out and form a core package semi-finished product.

[0079] S10. Assemble the pre-processed anode pins 14 onto the core package semi-finished product to achieve anode lead-out and form capacitor core package 1;

[0080] S11. Encapsulate the capacitor core 1 with epoxy resin encapsulant to form a shell and make a capacitor semi-finished product.

[0081] S12. A tin plating layer is prepared on the exposed surfaces of the anode terminal portion 143 and the cathode terminal portion 153 of the capacitor semi-finished product by electroplating to form terminals suitable for surface mounting, thereby producing a solid aluminum electrolytic capacitor 2.

[0082] Specifically, step S8 is as follows:

[0083] S81. The metal strip is integrally stamped to form the cathode pin 15;

[0084] S82. The copper-clad insulating laminate is processed into substrate 13;

[0085] S83. Apply a metal adhesive (such as high-strength instant metal adhesive) to the cathode copper foil 133 of the substrate 13, and attach and fix the cathode tongue 151 on the cathode pin 15 facing the cathode terminal portion 153 to the cathode copper foil 133; at the same time, a set of rectangular extensions 132 on the substrate 13 near the cathode copper foil 133 are fitted with a set of cathode rectangular notches 154 on the cathode pin 15.

[0086] S84. First, apply conductive silver paste to the side of the cathode tongue 151 that is away from the cathode terminal 153, and then place a conductive metal mesh 12. After the conductive silver paste is cured, the conductive metal mesh 12 is fixedly connected to the cathode tongue 151 and forms an electrical connection to form a cathode base.

[0087] Specifically, step S9 is as follows:

[0088] S91. First, a layer of conductive graphite emulsion is coated on the surface of the conductive metal mesh 12 on the cathode base, and then a capacitor core 11 is stacked so that the conductive metal mesh 12 is attached to one side of the cathode part 111 of the capacitor core 11. When stacking, the side of the capacitor core 11 with the metal pad 1131 on the anode part 113 faces the cathode base.

[0089] S92. First, a layer of conductive graphite emulsion is coated on the surface of the cathode portion 111 of the stacked capacitor core 11, and then a conductive metal mesh 12 is stacked.

[0090] S93. Repeat steps S91 and S92 in sequence until the number of layers of capacitor core 11 reaches the designed number of layers. Finally, stack a conductive metal mesh 12 to form a sandwich stack.

[0091] S94. Apply conductive silver paste to the three side surfaces of the sandwich stack to form a silver paste covering strip 16, so that the cathode part 111 of the N capacitor cores 11, the N+1 conductive metal meshes 12, and the cathode pins 15 are electrically connected to achieve cathode lead-out and form a core package semi-finished product.

[0092] Specifically, step S10 is as follows:

[0093] S101. The metal strip is integrally stamped to form the anode pin 14;

[0094] S102, A set of rectangular extensions 132 on the substrate 13 away from the cathode copper foil 133 in the core package semi-finished product are fitted with a set of anode rectangular notches 144 on the anode pin 14, and the anode portions 113 of N capacitor cores 11 are stacked on the anode tongue 145, and the rectangular protrusions 1131b of each capacitor core 11 are embedded in the anode cutout portion 146.

[0095] S103. The rectangular protrusion 1131b of each capacitor core 11 is fixedly connected to the anode cutout 146 by laser welding, so that the anode part 113 of each capacitor core 11 is electrically connected to the anode pin 14, realizing the anode lead-out and forming the capacitor core package 1.

[0096] Please refer to Figure 1-9 Embodiment 1 of the present invention is as follows:

[0097] S1. Convert 3VF into aluminum foil and cut it into rectangles to form the first aluminum foil;

[0098] S2. Coat the first aluminum foil with barrier adhesive to prepare insulating barrier tape 112, divide the anode area and the cathode area, and obtain the second aluminum foil.

[0099] S3. The dielectric layer on the cathode side of the second aluminum foil is reformed and repaired to obtain the third aluminum foil;

[0100] S4. A conductive polymer layer is formed on the cathode region surface of the third aluminum foil to obtain the fourth aluminum foil;

[0101] S5. The cathode region of the fourth aluminum foil is impregnated with conductive graphite emulsion and then dried to form a conductive carbon paste layer, thus obtaining the fifth aluminum foil.

[0102] S6. A pre-processed metal pad 1131 is welded onto one side of the anode region 1132 of the fifth aluminum foil to obtain the capacitor core 11.

[0103] The metal gasket 1131 includes a rectangular main body 1131a, and two rectangular protrusions 1131b are provided on one long side of the rectangular main body 1131a. The rectangular protrusions 1131b are located away from the insulating barrier tape 112. The metal gasket 1131 is made of iron-nickel alloy.

[0104] S7. The copper wire mesh cut into rectangles is soaked in conductive silver paste and then dried to form a conductive metal mesh 12. The length of the conductive metal mesh 12 is 85% of the length of the cathode part 111 of the capacitor core 11, and its width is 95% of the width of the cathode part 111 of the capacitor core 11.

[0105] The copper wire mesh is made of phosphor bronze wire with a diameter of 30 micrometers and a mesh count of 300.

[0106] S8. Assemble the pre-processed cathode pins 15 onto one end of the pre-processed substrate 13 using a mating and plugging method, and then bond and fix them. Next, bond and fix a conductive metal mesh 12 onto the cathode pins 15 to form a cathode base. Step S8 specifically involves:

[0107] S81. A cathode pin 15 is formed by integral stamping of a metal strip. The cathode pin 15 includes a cathode tongue 151, a cathode vertical portion 152, and a cathode terminal portion 153 integrally connected. The cathode tongue 151 and the cathode terminal portion 153 are respectively vertically arranged on opposite sides of the cathode vertical portion 152, and the cathode tongue 151 and the cathode terminal portion 153 are arranged in the same direction. The two free sides of the cathode vertical portion 152 are symmetrically arranged with cathode rectangular notches 154 that cooperate with the substrate 13. The cathode rectangular notches 154 are arranged away from the cathode terminal portion 153. The cathode tongue 151 is in contact with the conductive metal mesh 12 located at the bottom. The cathode pin 15 is made of copper or copper alloy.

[0108] S82. The copper-clad laminate is processed into a substrate 13. The substrate 13 includes a rectangular body 131, two sets of rectangular extensions 132 and a cathode copper-clad foil 133. The two sets of rectangular extensions 132 are respectively disposed at the four corners of the rectangular body 131 and form an H shape. The cathode copper-clad foil 133 is laid flat and fixed on one side of the rectangular body 131. The width of the cathode copper-clad foil 133 is equal to the width of the rectangular body 131, and the length of the cathode copper-clad foil 133 is 60% of the length of the rectangular body 131.

[0109] S83. Apply a metal adhesive (e.g., high-strength instant metal adhesive) to the cathode copper foil 133 of the substrate 13, and attach and fix the cathode tongue 151 on the cathode pin 15 facing the cathode terminal portion 153 to the cathode copper foil 133. At the same time, a set of rectangular extensions 132 on the substrate 13 near the cathode copper foil 133 are fitted with a set of cathode rectangular notches 154 on the cathode pin 15.

[0110] S84. First, apply conductive silver paste to the side of the cathode tongue 151 that is away from the cathode terminal 153, and then place a conductive metal mesh 12. After the conductive silver paste is cured, fix the conductive metal mesh 12 to the cathode tongue 151 and form an electrical connection to form a cathode base.

[0111] S9. On the cathode base, four capacitor cores 11 and four conductive metal meshes 12 are alternately stacked to form a sandwich stack. Then, conductive silver paste is applied to the three side surfaces of the sandwich stack and cured to form a silver paste covering strip 16, thereby achieving cathode lead-out and forming a core package semi-finished product. Step S9 is specifically as follows:

[0112] S91. First, a layer of conductive graphite emulsion is coated on the surface of the conductive metal mesh 12 on the cathode base, and then a capacitor core 11 is stacked so that the conductive metal mesh 12 is attached to one side of the cathode part 111 of the capacitor core 11. When stacking, the side of the capacitor core 11 with the metal pad 1131 on the anode part 113 faces the cathode base.

[0113] S92. First, a layer of conductive graphite emulsion is coated on the surface of the cathode portion 111 of the stacked capacitor core 11, and then a conductive metal mesh 12 is stacked.

[0114] S93. Repeat steps S91 and S92 in sequence until the number of layers of capacitor core 11 reaches the designed number of layers. Finally, stack a conductive metal mesh 12 to form a sandwich stack.

[0115] S94. Apply conductive silver paste to the three sides of the sandwich stack to form a silver paste covering strip 16, so that the cathode part 111 of the four capacitor cores 11, the five conductive metal meshes 12, and the cathode pins 15 are electrically connected to achieve cathode lead-out and form a core package semi-finished product.

[0116] S10. Assemble the pre-processed anode pins 14 onto the core package semi-finished product to achieve anode lead-out and form capacitor core package 1; Step S10 specifically includes:

[0117] S101. An anode pin 14 is formed by integral stamping of a metal strip. The anode pin 14 includes an integrally connected anode horizontal portion 141, an anode vertical portion 142, and an anode terminal portion 143. The anode horizontal portion 141 and the anode terminal portion 143 are respectively vertically arranged on opposite sides of the anode vertical portion 142, and the anode horizontal portion 141 and the anode terminal portion 143 are arranged in the same direction. The two free sides of the anode vertical portion 142 are symmetrically provided with anode rectangular notches 1 that cooperate with the substrate 13. 44, and the rectangular notch 144 of the anode is located near the anode terminal portion 143. The vertical portion 142 of the anode is formed by cutting and bending to form two corresponding anode tongues 145 and two anode hollow portions 146. The anode tongues 145 and the anode hollow portions 146 are rectangular. The anode tongues 145 are in contact with the metal pad 1131 located at the bottom. The rectangular protrusion 1131b of the metal pad 1131 is embedded in the anode hollow portion 146. The material of the anode pin 14 is copper or copper alloy.

[0118] S102, A set of rectangular extensions 132 on the substrate 13 away from the cathode copper foil 133 in the core package semi-finished product are fitted with a set of anode rectangular notches 144 on the anode pin 14, and the anode portions 113 of the four capacitor cores 11 are stacked on the anode tongue 145, and the rectangular protrusions 1131b of each capacitor core 11 are embedded in the anode cutout portion 146.

[0119] S103. The rectangular protrusion 1131b of each capacitor core 11 is fixedly connected to the anode cutout 146 by laser welding, so that the anode part 113 of each capacitor core 11 is electrically connected to the anode pin 14, realizing the anode lead-out and forming the capacitor core package 1.

[0120] S11. The capacitor core package 1 is encapsulated with epoxy resin encapsulant to form a shell and make a capacitor semi-finished product. That is, after encapsulation, except for the side of the anode terminal 143 and the cathode terminal 153 that is away from the substrate 13, which are flush with the outer surface of the bottom of the shell, the rest of the capacitor core package 1 is covered by the shell.

[0121] S12. A tin plating layer is prepared on the exposed surfaces of the anode terminal portion 143 and the cathode terminal portion 153 of the capacitor semi-finished product by electroplating to form terminals suitable for surface mounting, thereby producing a solid aluminum electrolytic capacitor 2.

[0122] Comparative Example 1:

[0123] S1. Cut the 3VF foil into rectangles to form the first aluminum foil;

[0124] S2. Apply insulating adhesive to the first aluminum foil to divide the anode area and the cathode area, forming the second aluminum foil;

[0125] S3. The dielectric layer on the cathode side of the second aluminum foil is re-formed and repaired to form the third aluminum foil;

[0126] S4. Prepare a conductive polymer layer on the cathode region surface of the third aluminum foil to form a fourth aluminum foil;

[0127] S5. A conductive carbon paste layer is formed on the cathode region surface of the fourth aluminum foil to form the fifth aluminum foil;

[0128] S6. A conductive silver paste layer is formed on the cathode region surface of the fifth aluminum foil to form a capacitor core;

[0129] S7. Connect the four capacitor cores to the external metal strip to form a capacitor core package;

[0130] S8. Solid aluminum electrolytic capacitors are obtained by encapsulating the capacitor core with epoxy resin and bending the leads.

[0131] The solid aluminum electrolytic capacitors prepared in the above embodiments and comparative examples are shown in Table 1.

[0132] Table 1. Test data for examples and comparative examples.

[0133]

[0134] As can be seen from the test data of the above embodiments and comparative examples, compared with the comparative examples, the surface mount solid aluminum electrolytic capacitors obtained in the embodiments have lower ESR and leakage current values, and better moisture resistance.

[0135] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0136] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0137] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A surface-mount solid aluminum electrolytic capacitor, characterized in that: It includes a capacitor core package (1), which is encapsulated and electroplated to form a solid aluminum electrolytic capacitor (2). The capacitor core package (1) includes N capacitor cores (11), N+1 conductive metal meshes (12), a substrate (13), anode leads (14), cathode leads (15), and a silver paste covering strip (16). The capacitor core (11) includes an anode portion (113), a cathode portion (111), and an insulating barrier tape (112). The anode portion (113) includes an anode region (1132) of a fifth aluminum foil and a metal pad (1131). One side of the anode region (1132) of the fifth aluminum foil is laid flat and electrically connected to the metal pad (1131). The metal pad (1131) includes a rectangular main body portion (1131a). Two rectangular protrusions (1131b) are provided on one long side of the rectangular main body portion (1131a). The rectangular protrusions (1131b) are located away from the insulating barrier tape (112). The cathode portion (111) includes a cathode region of a fifth aluminum foil. The cathode region of the fifth aluminum foil includes a cathode region of a second aluminum foil, a conductive polymer layer, and a conductive carbon paste layer. The insulating barrier tape (112) separates the anode portion (113) and the cathode portion (111). N+1 conductive metal meshes (12) and N capacitor cores (11) are stacked sequentially. The conductive metal meshes (12) are disposed on the cathode portion (111) of the capacitor cores (11), and the side of the capacitor cores (11) with metal pads (1131) on the anode portion (113) faces the substrate (13). The anode pins (14) and cathode pins (15) are respectively inserted and fixed at both ends of the substrate (13). The bottommost conductive metal mesh (12) is in contact with the cathode pins (15), and the bottommost metal pads (1131) are stacked together. 131) In contact with the anode pin (14), the rectangular protrusion (1131b) of the metal pad (1131) is embedded in the anode pin (14), and the silver paste covering strip (16) is provided on the three side surfaces of the sandwich stack formed by the cathode part (111) of N capacitor cores (11) and N+1 conductive metal meshes (12), and the silver paste covering strip (16) is embedded between the cathode parts (111) of two adjacent capacitor cores (11), between the cathode part (111) of the lowest capacitor core (11) and the cathode tongue (151) of the cathode pin (15); The substrate (13) includes a rectangular body (131), two sets of rectangular extensions (132) and a cathode copper foil (133). The two sets of rectangular extensions (132) are respectively disposed at the four corners of the rectangular body (131) and form an H shape. The cathode copper foil (133) is laid flat and fixed on one side of the rectangular body (131). The width of the cathode copper foil (133) is equal to the width of the rectangular body (131), and the length of the cathode copper foil (133) is 50%-65% of the length of the rectangular body (131).

2. The surface mount solid aluminum electrolytic capacitor according to claim 1, characterized in that: The length of the conductive metal mesh (12) is 80%-90% of the length of the cathode part (111) of the capacitor core (11), and the width of the conductive metal mesh (12) is 90%-100% of the width of the cathode part (111) of the capacitor core (11).

3. A surface-mount solid aluminum electrolytic capacitor according to claim 2, characterized in that: The conductive metal mesh (12) is made by impregnating a copper wire woven mesh with conductive silver paste and drying it. The copper wire woven mesh is made of phosphor bronze wire with a wire diameter of 25-35 micrometers and a mesh count of 200-400 mesh.

4. A surface-mount solid aluminum electrolytic capacitor according to claim 1, characterized in that: The anode pin (14) includes an integrally connected horizontal anode portion (141), a vertical anode portion (142), and an anode terminal portion (143); the vertical anode portion (142) has the horizontal anode portion (141) and the anode terminal portion (143) vertically arranged on opposite sides, and the horizontal anode portion (141) and the anode terminal portion (143) are arranged in the same direction; the vertical anode portion (142) has two free sides symmetrically arranged with rectangular anode notches (144) that cooperate with the substrate (13), and the anode... A rectangular notch (144) is provided near the anode terminal (143). The vertical anode portion (142) is processed by cutting and bending to form two corresponding anode tongues (145) and two anode hollow portions (146). The anode tongues (145) and anode hollow portions (146) are rectangular. The anode tongues (145) are in contact with the metal pad (1131) located at the bottom. The rectangular protrusion (1131b) of the metal pad (1131) is embedded in the anode hollow portion (146).

5. A surface-mount solid aluminum electrolytic capacitor according to claim 1, characterized in that: The cathode pin (15) includes an integrally connected cathode tongue (151), cathode vertical portion (152), and cathode terminal portion (153); the cathode vertical portion (152) has a cathode tongue (151) and a cathode terminal portion (153) vertically arranged on opposite sides, and the cathode tongue (151) and cathode terminal portion (153) are arranged in the same direction. The two free sides of the cathode vertical portion (152) are symmetrically arranged with cathode rectangular notches (154) that cooperate with the substrate (13), and the cathode rectangular notches (154) are arranged away from the cathode terminal portion (153). The cathode tongue (151) is in contact with the conductive metal mesh (12) located at the bottom.

6. A method for preparing a surface-mount solid aluminum electrolytic capacitor according to any one of claims 1-5, characterized in that: The preparation method includes the following steps: S1. Cut the aluminum foil into rectangles to form the first aluminum foil; S2. Coat the first aluminum foil with barrier adhesive to prepare an insulating barrier tape (112), divide the anode area and the cathode area, and obtain the second aluminum foil; S3. The dielectric layer on the cathode side of the second aluminum foil is reformed and repaired to obtain the third aluminum foil; S4. A conductive polymer layer is formed on the cathode region surface of the third aluminum foil to obtain the fourth aluminum foil; S5. The cathode region of the fourth aluminum foil is impregnated with conductive graphite emulsion and then dried to form a conductive carbon paste layer, thus obtaining the fifth aluminum foil. S6. A pre-processed metal pad (1131) is welded onto one side of the anode region (1132) of the fifth aluminum foil to obtain a capacitor core (11). S7. The copper wire mesh cut into rectangles is immersed in conductive silver paste and then dried to make a conductive metal mesh (12). S8. The pre-processed cathode pins (15) are assembled on one end of the pre-processed substrate (13) in a mating and plugging manner, and then a conductive metal mesh (12) is glued and fixed on the cathode pins (15) to form a cathode base. S9. On the cathode base, N capacitor cores (11) and N conductive metal meshes (12) are stacked alternately to form a sandwich stack. Then, conductive silver paste is applied to the three sides of the sandwich stack and cured to form a silver paste covering strip (16) to achieve cathode lead-out and form a core package semi-finished product. S10. Assemble the pre-processed anode pins (14) onto the core package semi-finished product to realize anode lead-out and form capacitor core package (1). S11. Encapsulate the capacitor core (1) with epoxy resin encapsulant to form a shell and make a capacitor semi-finished product. S12. The capacitor semi-finished product is electroplated to form a tin plating layer on the surface of the anode terminal (143) and cathode terminal (153) exposed on the outer shell, so as to form a terminal suitable for surface mounting, and to make a solid aluminum electrolytic capacitor (2).

7. The method for preparing a surface-mount solid aluminum electrolytic capacitor according to claim 6, characterized in that: Step S8 specifically involves: S81. The metal strip is formed into cathode pins by integral stamping (15). S82. The copper-clad insulating laminate is processed into a substrate (13). S83. Apply a metal adhesive to the cathode copper foil (133) of the substrate (13), and attach and fix the cathode tongue (151) on the cathode pin (15) facing the cathode terminal (153) to the cathode copper foil (133); at the same time, a set of rectangular extensions (132) on the substrate (13) near the cathode copper foil (133) are fitted with a set of cathode rectangular notches (154) on the cathode pin (15); S84. First, apply conductive silver paste to the side of the cathode tongue (151) that is away from the cathode terminal (153), and then place a conductive metal mesh (12). After the conductive silver paste is cured, the conductive metal mesh (12) and the cathode tongue (151) are fixedly connected and an electrical connection is formed to form a cathode base.

8. The method for preparing a surface-mount solid aluminum electrolytic capacitor according to claim 6, characterized in that: Step S9 specifically involves: S91. First, a layer of conductive graphite emulsion is coated on the surface of the conductive metal mesh (12) on the cathode base, and then a capacitor core (11) is stacked so that the conductive metal mesh (12) is attached to one side of the cathode part (111) of the capacitor core (11). When stacking, the side of the capacitor core (11) with the metal pad (1131) on the anode part (113) faces the cathode base. S92. First, a layer of conductive graphite emulsion is applied to the surface of the cathode part (111) of the stacked capacitor core (11), and then a conductive metal mesh (12) is stacked. S93. Repeat steps S91 and S92 in sequence until the number of layers of the capacitor core (11) reaches the designed number of layers. Finally, stack a conductive metal mesh (12) to form a sandwich stack. S94. Apply conductive silver paste to the three sides of the sandwich stack to form a silver paste covering strip (16), so that the cathode part (111), N+1 conductive metal mesh (12), and cathode pin (15) of the N capacitor cores (11) are electrically connected to achieve cathode lead-out and form a core package semi-finished product.

9. The method for preparing a surface-mount solid aluminum electrolytic capacitor according to claim 6, characterized in that: Step S10 specifically involves: S101, The metal strip is stamped in one piece to form the anode pin (14). S102, A set of rectangular extensions (132) on the substrate (13) of the core package semi-finished product away from the cathode copper foil (133) are fitted with a set of anode rectangular notches (144) on the anode pin (14), and the anode portions (113) of N capacitor cores (11) are stacked on the anode tongue (145), and the rectangular protrusions (1131b) of each capacitor core (11) are embedded in the anode cutout portion (146); S103. The rectangular protrusion (1131b) of each capacitor core (11) is fixedly connected to the anode cutout (146) by laser welding, so that the anode part (113) of each capacitor core (11) is electrically connected to the anode pin (14), thereby realizing the anode lead-out and forming a capacitor core package (1).

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