A chip type laminated solid aluminum electrolytic capacitor and a method for manufacturing the same

Abstract

The application discloses a sheet type laminated solid-state aluminum electrolytic capacitor and a preparation method thereof. The capacitor comprises a core package and a resin shell. The resin shell is packaged outside the core package and forms the solid-state aluminum electrolytic capacitor. The core package comprises a core package prototype, an anode lead frame and a cathode lead frame. The core package prototype comprises arc-shaped cores and metal shafts. A conductive silver paste layer is arranged in a cathode gap between two adjacent arc-shaped cores. The fixed position of the anode part of each core is at the center of the core, which is surrounded by the annular cathode part. Each core cathode part is integrally connected through the conductive silver paste, so that the whole core package presents a disc structure. The core package with the structure is more compact and has no gap. In the packaging process, the organic resin can be prevented from being squeezed into the core layers, the core deformation damage is prevented, the leakage current and ESR increase is prevented, the capacity shortage caused by the delamination between the cores and even the capacitor failure can be further prevented. Meanwhile, the cathode part of the core has a larger area and smaller ESR.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid aluminum electrolytic capacitor, in particular to a chip type laminated solid aluminum electrolytic capacitor and a preparation method thereof. BACKGROUND

[0002] The chip type laminated solid aluminum electrolytic capacitor uses conductive polymer material as solid electrolyte, has a core package structure of multiple layers of cores in parallel stack and a product appearance suitable for surface mounting, and has the advantages of smaller size, better basic electrical performance, longer service life, excellent frequency impedance characteristics and temperature characteristics, more environmental protection and safety characteristics, and the like compared with traditional liquid aluminum electrolytic capacitors.

[0003] At present, the chip type laminated solid aluminum electrolytic capacitor is mostly designed in a square appearance, and the basic preparation process thereof is to cut the formed foil into a rectangular strip-shaped foil, divide the anode region and the cathode region on the foil by using a barrier glue, form a conductive polymer solid electrolyte layer on the surface of the cathode region of the foil, and then sequentially cover a conductive carbon paste layer and a silver paste layer on the conductive polymer solid electrolyte layer to form a capacitor unit; a plurality of capacitor units are stacked in a parallel manner on the upper and lower surfaces of an external lead frame, and the anode and the cathode are respectively led out, then encapsulated by using epoxy resin, and finally the lead wires exposed outside the resin shell are bent to form external terminals.

[0004] The preparation method of the chip type laminated solid aluminum electrolytic capacitor has the following disadvantages:

[0005] 1. The chip type laminated solid aluminum electrolytic capacitor uses a rectangular strip-shaped foil to make a rectangular strip-shaped core, which is stacked in layers in parallel on an external planar lead frame, and the stacking manner is generally as follows: the anode region of the core is welded to the anode tongue of the external lead frame, the cathode regions of the core are bonded by using conductive silver glue, and then bonded to the cathode tongue of the external lead frame, and the anode and the cathode are respectively led out from the two ends of the long side of the core. In order to ensure the welding strength of the anode region of the core, the anode region needs to have sufficient length, and generally, the length of the cathode region accounts for at most 80% of the total length of the core, that is, the area of the cathode region accounts for 80% of the total area of the core. When the aluminum foil model and the capacity extraction rate are fixed, the capacitance of the single chip core of the chip type laminated solid aluminum electrolytic capacitor is proportional to the area of the cathode region (calculation formula: single chip core capacity = aluminum foil static capacity * cathode region area * capacity extraction rate). When the size of the capacitor is fixed, the limited aluminum foil area utilization rate limits the development of larger capacity capacitors.

[0006] 2. The two right-angle parts at the bottom of the square foil cathode region are prone to burrs during the preparation of the conductive polymer solid electrolyte layer and the conductive carbon paste layer and the silver paste layer, which affects the flatness of the core package and increases the leakage current of the capacitor.

[0007] 3. In traditional square-plate multilayer solid aluminum electrolytic capacitors, a planar lead frame is used. After the core is laid on both the top and bottom surfaces, a gap exists between the anode and cathode tongues of the lead frame. During the encapsulation process, organic resin encapsulant can easily squeeze into this gap, causing compression deformation of the core, resulting in leakage current, increased ESR, and in severe cases, delamination, leading to insufficient capacitance and capacitor failure. Therefore, this invention designs a multilayer multilayer solid aluminum electrolytic capacitor and its fabrication method to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide a chip-type multilayer solid aluminum electrolytic capacitor and its preparation method to solve the above-mentioned technical problems.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a chip-type multilayer solid aluminum electrolytic capacitor, comprising a capacitor core and a resin shell, wherein the resin shell is encapsulated outside the capacitor core to form a solid aluminum electrolytic capacitor;

[0010] The capacitor core package includes a core package prototype, an anode lead frame, and a cathode lead frame;

[0011] The core package prototype includes an arc-shaped core body and a metal shaft, and the chord portions of several arc-shaped core pieces in the arc-shaped core body are aligned.

[0012] The bow-shaped core includes a third aluminum foil in the shape of a bow. A bow-shaped through hole is formed at the center of the third aluminum foil. A bow-shaped protrusion of the aluminum foil is perpendicularly connected to the chord of the bow-shaped through hole, and the bow-shaped protrusion is connected to the first aluminum foil. The outer edge of the bow-shaped through hole is coated with an annular insulating barrier tape. The area of ​​the third aluminum foil outside the annular insulating barrier tape is the cathode area, and the bow-shaped protrusion is the anode area. The cathode area of ​​the bow-shaped core is provided with a first conductive polymer solid electrolyte layer, a second conductive polymer solid electrolyte layer, and a conductive carbon paste layer in sequence from the inside to the outside.

[0013] The metal shaft passes sequentially through the arc-shaped through holes of several third aluminum foils, and the arc-shaped protrusions of the third aluminum foils are electrically connected to the metal shaft. After the arc-shaped core is prepared, the part of one end of the metal shaft that is exposed outside the arc-shaped core is completely cut off, and the part of the other end of the metal shaft that is exposed outside the arc-shaped core is retained to an appropriate length to form a protruding end.

[0014] The anode lead frame is electrically connected to the protruding end of the metal shaft, and the cathode lead frame is electrically connected to the cathode region of the surface where the protruding end is located.

[0015] Preferably, the central angle corresponding to the arc of the bow-shaped through hole is between 270 degrees and 300 degrees, and the diameter of the bow-shaped through hole is 10% to 15% of the diameter of the first aluminum foil.

[0016] Preferably, the width of the annular insulating barrier tape is 5%-10% of the diameter of the third aluminum foil, and the thickness of the annular insulating barrier tape is 0.1mm-0.2mm.

[0017] Preferably, the distance between the two adjacent third aluminum foils on the metal shaft is equal to the thickness of a single arc-shaped core.

[0018] A preparation method of a chip-type laminated solid-state aluminum electrolytic capacitor, comprising the following steps:

[0019] S1, punching the formed aluminum foil into an arc shape to form a first aluminum foil;

[0020] S2, cutting at the center of the first aluminum foil to obtain an arc-shaped through hole, a chord part, and an arc-shaped aluminum foil connected with the first aluminum foil, and bending the arc-shaped aluminum foil at a right angle with the plane of the first aluminum foil to obtain an arc-shaped aluminum foil protruding part, thereby forming a second aluminum foil;

[0021] S3, coating insulating barrier glue on both sides of the outer edge of the arc-shaped through hole of the second aluminum foil to form an annular insulating barrier tape, thereby dividing the anode region and the cathode region, and forming a third aluminum foil;

[0022] S4, passing a metal shaft through the arc-shaped through holes of a plurality of third aluminum foils, and electrically connecting the arc-shaped aluminum foil protruding part bent at a right angle on each third aluminum foil with the metal shaft, thereby forming a plurality of fourth aluminum foils fixed on the metal shaft;

[0023] S5, re-forming the side dielectric layer of the plurality of fourth aluminum foils fixed on the metal shaft, thereby forming a plurality of fifth aluminum foils fixed on the metal shaft;

[0024] S6, preparing a first conductive polymer solid electrolyte layer on the surface of the cathode region of the plurality of fifth aluminum foils fixed on the metal shaft by a chemical polymerization method, thereby forming a plurality of sixth aluminum foils fixed on the metal shaft;

[0025] S7, preparing a second conductive polymer solid electrolyte layer on the surface of the cathode region of the plurality of sixth aluminum foils fixed on the metal shaft by a method of impregnating a conductive polymer dispersion liquid and drying, thereby forming a plurality of seventh aluminum foils fixed on the metal shaft;

[0026] S8, preparing a conductive carbon paste layer by coating a conductive carbon paste on the surface of the cathode region of the plurality of seventh aluminum foils fixed on the metal shaft and drying, thereby forming a plurality of arc-shaped cores fixed on the metal shaft;

[0027] S9, immersing the cathode region of the plurality of arc-shaped cores fixed on the metal shaft into a conductive silver paste, and preparing a conductive silver paste layer after drying and curing, thereby forming an arc-shaped core body fixed on the metal shaft;

[0028] S10, cutting off the part of the metal shaft exposed outside the arc-shaped core body, leaving the other end of the metal shaft with a proper length to form a protruding end, and forming a core package prototype;

[0029] S11, electrically connecting the anode lead frame of the external device with the protruding end of the core package prototype, and electrically connecting the cathode lead frame of the external device with the cathode area of the core package prototype, to form a capacitor core package;

[0030] S11, encapsulating the capacitor core package with epoxy resin to form a resin shell outside the capacitor core package, and obtaining a solid aluminum electrolytic capacitor.

[0031] Preferably, the re-formation of the side edge dielectric layer in step S5 is performed by a method of immersion in a formation solution and electrically formed, and the method is specifically: rotating a plurality of fourth aluminum foil cathode areas driven by the metal shaft at a uniform speed in the formation solution, the rotating speed is 5r / min-30r / min, the immersion depth is the entire cathode area immersed, and the electrically formed time is 20min-100min.

[0032] Preferably, the chemical polymerization method in step S6 is performed by a method of alternately immersing in an oxidizing solution and a reducing solution and drying, and the method is specifically: rotating a plurality of fifth aluminum foil cathode areas driven by the metal shaft at a uniform speed in the oxidizing solution or the reducing solution, the rotating speed is 5r / min-30r / min, the immersion depth is the entire cathode area immersed, and the immersion time is 60S-120S.

[0033] Preferably, the method of immersing in the conductive polymer dispersion liquid and drying in step S7 is specifically: rotating a plurality of sixth aluminum foil cathode areas driven by the metal shaft at a uniform speed in the conductive polymer dispersion liquid, the rotating speed is 5r / min-10r / min, the immersion depth is the entire cathode area immersed, the immersion time is 60S-120S, the drying temperature is 40℃-75℃, and the drying time is 2min-10min.

[0034] Preferably, the method of preparing conductive carbon paste and drying in step S8 is specifically: rotating a plurality of seventh aluminum foil cathode areas driven by the metal shaft at a uniform speed in the conductive carbon paste, the rotating speed is 5r / min-10r / min, the immersion depth is 80%-90% of the length of the entire cathode area, the immersion time is 60S-120S, the drying temperature is 80℃-130℃, and the drying time is 10min-30min.

[0035] Preferably, the method for preparing the conductive silver paste layer in step S9 is specifically as follows: a plurality of arc-shaped core cathode regions are driven by a metal rotating shaft to rotate uniformly in the conductive silver paste at a rotating speed of 5 r / min-10 r / min, the immersion depth is 60%-70% of the length of the entire cathode region, the immersion time is 60 S-120 S, the drying temperature is 80°C-150°C, and the drying time is 10 min-30 min.

[0036] Compared with the prior art, the application has the following beneficial effects:

[0037] 1) The arc-shaped core appearance and the mode of leading out the anode from the core center can make the cathode region area ratio larger under the condition of the same total core area. According to the design size specified in the application, the cathode region area utilization rate can reach about 94%-98%, which is greatly improved compared with the maximum value 80% of the cathode region area utilization rate of the square core.

[0038] 2) The arc-shaped foil has no sharp corner structure, which can avoid burr at the sharp corner in the preparation process of the conductive polymer layer and the conductive paste layer, and reduce the capacitor leakage current.

[0039] 3) In the application, the fixed positions of the anode parts of the cores are at the centers of the cores, which are surrounded by the ring-shaped cathode parts. The cathode parts of the cores are integrally connected through the conductive silver paste, so that the core package presents a disc-shaped structure. The core package of this structure is more compact and has no gap. In the packaging process, the organic resin can be prevented from being squeezed into the core layers, the deformation of the cores caused by the organic resin can be prevented, the leakage current and ESR increase can be prevented, and the delamination between the cores can be prevented to cause insufficient capacity and even capacitor failure. Moreover, the cathode part area of the core is larger, and the ESR is smaller. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0041] Figure 1 It is a structural schematic diagram of the arc-shaped core in the application.

[0042] Figure 2 It is a structural sectional view of the arc-shaped core in the application.

[0043] Figure 3 It is a structural schematic diagram of the core package in the application.

[0044] Figure 4 It is a structural schematic diagram of the core package in the application.

[0045] Figure 5 Fig. 1 is a structural schematic diagram of the anode lead frame in the present application;

[0046] Figure 6 Fig. 2 is a structural schematic diagram of the cathode lead frame in the present application;

[0047] Figure 7 Fig. 3 is a structural schematic diagram of the solid aluminum electrolytic capacitor in the present application;

[0048] Figure 8 Fig. 4 is a flow chart of the preparation method in the present application.

[0049] In the drawings, the components represented by each reference numeral are listed as follows:

[0050] 1, arc-shaped core; 11, third aluminum foil; 12, arc-shaped through hole; 13, arc-shaped aluminum foil protruding part; 14, circular ring-shaped insulating barrier adhesive tape; 15, first conductive polymer solid electrolyte layer; 16, second conductive polymer solid electrolyte layer; 17, conductive carbon paste layer; 18, protruding end; 2, metal shaft; 3, core package prototype; 4, anode lead frame; 41, arc-shaped part; 42, first connecting part; 43, platform part; 44, second connecting part; 45, L-shaped terminal part; 5, cathode lead frame; 51, planar tongue part; 52, connecting part; 53, L-shaped terminal part; 6, capacitor core package; 7, resin shell; 8, solid aluminum electrolytic capacitor. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0052] Please refer to Figures 1-8 The present application provides a technical solution: a sheet-type laminated solid aluminum electrolytic capacitor, which comprises a capacitor core package 6 and a resin shell 7, the resin shell 7 is packaged outside the capacitor core package 6 and forms a solid aluminum electrolytic capacitor 8;

[0053] The capacitor core package 6 comprises a core package prototype 3, an anode lead frame 4 and a cathode lead frame 5;

[0054] The core package prototype 3 comprises an arc-shaped core body and a metal shaft 2, and the chord parts of a plurality of arc-shaped cores 1 in the arc-shaped core body are arranged in alignment;

[0055] The arc-shaped core 1 comprises an arc-shaped third aluminum foil 11, a circular center of the third aluminum foil 11 is provided with an arc-shaped through hole 12, a chord of the arc-shaped through hole 12 is vertically connected with an arc-shaped aluminum foil protruding part 13, the arc-shaped aluminum foil protruding part 13 is connected with the first aluminum foil, an outer edge of the arc-shaped through hole 12 is coated with a circular ring-shaped insulating barrier adhesive tape 14, a region of the third aluminum foil 11 outside the circular ring-shaped insulating barrier adhesive tape 14 is a cathode region, and the arc-shaped aluminum foil protruding part 13 is an anode region; the cathode region of the arc-shaped core 1 is sequentially provided with a first conductive polymer solid electrolyte layer 15, a second conductive polymer solid electrolyte layer 16 and a conductive carbon paste layer 17 from inside to outside.

[0056] The metal shaft 2 sequentially passes through the arc-shaped through holes 12 of the third aluminum foils 11, and the arc-shaped aluminum foil protruding parts 13 of the third aluminum foils 11 are electrically connected with the metal shaft 2; after the arc-shaped core body is prepared, all parts of the metal shaft 2 exposed outside the arc-shaped core body are cut off, and the part of the metal shaft 2 exposed outside the arc-shaped core body is reserved with a proper length to form a protruding end 18.

[0057] The anode lead frame 4 is electrically connected with the protruding end 18 of the metal shaft 2, and the cathode lead frame 5 is electrically connected with the cathode region of the surface where the protruding end 18 is located.

[0058] Specifically, the central angle corresponding to the arc of the arc-shaped through hole 12 is between 270 degrees and 300 degrees, and the diameter of the arc-shaped through hole 12 is 10% to 15% of the diameter of the first aluminum foil.

[0059] Specifically, the width of the circular ring-shaped insulating barrier adhesive tape 14 is 5% to 10% of the diameter of the third aluminum foil, and the thickness of the circular ring-shaped insulating barrier adhesive tape 14 is 0.1 mm to 0.2 mm.

[0060] Specifically, the distance between the adjacent two third aluminum foils 11 on the metal shaft 2 is equal to the thickness of a single arc-shaped core 1.

[0061] A preparation method of a sheet type laminated solid aluminum electrolytic capacitor, the preparation method comprising the following steps:

[0062] S1, punching a chemical conversion aluminum foil into an arc shape to form a first aluminum foil;

[0063] S2, cutting at a circular center position of the first aluminum foil to obtain an arc-shaped through hole 12 and an arc-shaped aluminum foil connected with the first aluminum foil at a chord, and bending the arc-shaped aluminum foil at a right angle with the first aluminum foil plane along the chord to obtain an arc-shaped aluminum foil protruding part 13, thereby forming a second aluminum foil;

[0064] S3, coating insulating barrier adhesives on both sides of the outer edge of the arc-shaped through hole 12 of the second aluminum foil to form a circular ring-shaped insulating barrier adhesive tape 14, thereby dividing an anode region and a cathode region, and forming a third aluminum foil 11;

[0065] S4, pass the metal shaft 2 through the arc-shaped through holes 12 on the third aluminum foils 11, and electrically connect the arc-shaped aluminum foil protrusions 13 bent at right angles on each third aluminum foil 11 with the metal shaft 2 to form several fourth aluminum foils fixed on the metal shaft 2;

[0066] S5, repair the side dielectric layers of the several fourth aluminum foils fixed on the metal shaft 2 by re-chemical formation to form several fifth aluminum foils fixed on the metal shaft 2;

[0067] S6, prepare a first conductive polymer solid electrolyte layer 15 on the cathode region surface of the several fifth aluminum foils fixed on the metal shaft 2 by a chemical polymerization method to form several sixth aluminum foils fixed on the metal shaft 2;

[0068] S7, prepare a second conductive polymer solid electrolyte layer 16 on the cathode region surface of the several sixth aluminum foils fixed on the metal shaft 2 by a method of impregnating a conductive polymer dispersion liquid and drying to form several seventh aluminum foils fixed on the metal shaft 2;

[0069] S8, prepare a conductive carbon paste layer 17 on the cathode region surface of the several seventh aluminum foils fixed on the metal shaft 2 by impregnating a conductive carbon paste and drying to form several arc-shaped cores 1 fixed on the metal shaft 2;

[0070] S9, immerse the cathode region of the several arc-shaped cores 1 fixed on the metal shaft 2 in a conductive silver paste, and prepare a conductive silver paste layer after drying and solidification to form an arc-shaped core body fixed on the metal shaft 2;

[0071] S10, cut off the part of the metal shaft 2 exposed outside the arc-shaped core body, and retain the part of the metal shaft 2 exposed outside the arc-shaped core body at a proper length to obtain a protruding end 18 to form a core package 3;

[0072] S11, electrically connect the anode lead frame 4 externally provided with the core package 3 to the protruding end 18 of the core package 3, and electrically connect the cathode lead frame 5 externally provided with the core package 3 to the cathode region of the surface of the core package 3 on which the protruding end 18 is located to form a capacitor core package 6;

[0073] S11, encapsulate the capacitor core package 6 with an epoxy resin to form a resin shell 7 outside the capacitor core package to obtain a solid aluminum electrolytic capacitor 8.

[0074] Specifically, the re-chemical formation repair of the side dielectric layer in step S5 is performed by a method of immersion in a chemical formation solution and electric chemical formation, and the method is specifically as follows: rotate the cathode region of the several fourth aluminum foils driven by the metal shaft 2 in the chemical formation solution at a uniform speed, the rotating speed is 5r / min-30r / min, the immersion depth is the entire cathode region is immersed, and the electric chemical formation time is 20min-100min.

[0075] Specifically, the chemical polymerization method in step S6 is performed by alternately immersing in oxidizing solution and reducing solution and drying, and the method is specifically as follows: the metal shaft 2 drives a plurality of pieces of the fifth aluminum foil cathode region to rotate uniformly in the oxidizing solution or the reducing solution, the rotating speed is 5r / min-30r / min, the immersion depth is that the entire cathode region is immersed, and the immersion time is 60S-120S.

[0076] Specifically, the method of immersing in the conductive polymer dispersion liquid and drying in step S7 is specifically as follows: the metal shaft 2 drives a plurality of pieces of the sixth aluminum foil cathode region to rotate uniformly in the conductive polymer dispersion liquid, the rotating speed is 5r / min-10r / min, the immersion depth is that the entire cathode region is immersed, the immersion time is 60S-120S, the drying temperature is 40℃-75℃, and the drying time is 2min-10min.

[0077] Specifically, the method of immersing in the conductive carbon slurry and drying in step S8 is specifically as follows: the metal shaft 2 drives a plurality of pieces of the seventh aluminum foil cathode region to rotate uniformly in the conductive carbon slurry, the rotating speed is 5r / min-10r / min, the immersion depth is that 80%-90% of the length of the entire cathode region is immersed, the immersion time is 60S-120S, the drying temperature is 80℃-130℃, and the drying time is 10min-30min.

[0078] Specifically, the method of preparing the conductive silver slurry layer in step S9 is specifically as follows: the metal shaft 2 drives a plurality of pieces of the arc-shaped core cathode region to rotate uniformly in the conductive silver slurry, the rotating speed is 5r / min-10r / min, the immersion depth is that 60%-70% of the length of the entire cathode region is immersed, the immersion time is 60S-120S, the drying temperature is 80℃-150℃, and the drying time is 10min-30min.

[0079] Please refer to Figures 1-8 , the embodiment one of the present application is:

[0080] S1, the first aluminum foil is formed by punching the 3VF into an arc shape, wherein the central angle of the arc corresponding to the arc of the arc shape is between 340 degrees and 350 degrees, and the diameter of the arc corresponding to the arc of the arc shape is 10mm;

[0081] S2, the arc-shaped through hole 12 is cut at the central position of the first aluminum foil, the arc-shaped aluminum foil is bent along the chord to be perpendicular to the plane of the first aluminum foil to obtain the arc-shaped aluminum foil protruding part 13, and the second aluminum foil is formed; wherein the central angle of the arc corresponding to the arc-shaped through hole 12 is 280 degrees, and the diameter of the arc corresponding to the arc-shaped through hole 12 is 12% of the diameter of the first aluminum foil.

[0082] S3, coating insulation barrier glue on both sides of the outer edge of the arc-shaped through hole 12 of the second aluminum foil to form a circular ring-shaped insulation barrier adhesive tape 14, which divides the anode area and the cathode area, the area outside the ring-shaped insulation barrier adhesive tape is the cathode area, and the arc-shaped aluminum foil protruding part 13 inside the ring is the anode area, forming the third aluminum foil 11; wherein the width of the circular ring-shaped insulation barrier adhesive tape 14 is 8% of the diameter of the third aluminum foil, and the thickness is 0.15mm;

[0083] S4, the metal shaft 2 is sequentially inserted through the arc-shaped through hole 12 of the 5 pieces of third aluminum foil 11, so that the chord part of each piece of third aluminum foil 11 is aligned, and the arc-shaped aluminum foil protruding part 13 bent at a right angle on each piece of third aluminum foil 11 is welded on the metal shaft 2, so that the 5 pieces of third aluminum foil 11 are regularly arranged at a spacing of 0.4mm and fixed on the metal shaft 2, forming 5 pieces of fourth aluminum foil fixed on the metal shaft 2, wherein the diameter of the metal shaft 2 is 80%-90% (preferably 85%) of the diameter of the arc-shaped through hole 12, and the material of the metal shaft 2 is copper or copper alloy;

[0084] S5, the side edge dielectric layer of the 5 pieces of fourth aluminum foil fixed on the metal shaft 2 is repaired by re-formation, forming 5 pieces of fifth aluminum foil fixed on the metal shaft 2, wherein the re-formation repair of the side edge dielectric is carried out by immersion formation solution and electric formation, specifically: the cathode area of the 5 pieces of fourth aluminum foil driven by the metal shaft 2 rotates uniformly in the formation solution at a speed of 15r / min, the immersion depth is the whole cathode area, and the electric formation time is 30min.

[0085] S6, a first conductive polymer solid electrolyte layer 15 is formed on the surface of the cathode area of the 5 pieces of fifth aluminum foil fixed on the metal shaft 2 by chemical polymerization, forming 5 pieces of sixth aluminum foil fixed on the metal shaft 2, wherein the chemical polymerization is carried out by alternately immersing the oxidizing solution and reducing solution and drying, specifically: the cathode area of the 5 pieces of fifth aluminum foil driven by the metal shaft 2 rotates uniformly in the oxidizing solution or reducing solution at a speed of 15r / min, the immersion depth is the whole cathode area, the immersion time is 70S, the oxidizing solution is composed of oxidizing agent and solvent, the oxidizing agent is any one of potassium permanganate and ammonium persulfate, the reducing solution is composed of conductive polymer monomer, dopant and solvent, and the conductive polymer monomer is one or more of pyrrole and its derivatives, thiophene and its derivatives, and aniline and its derivatives.

[0086] S7, a second conductive polymer solid electrolyte layer 16 is prepared on the surface of the 5 sixth aluminum foil cathode regions fixed on the metal shaft 2 by a method of impregnating and drying a conductive polymer dispersion liquid, and a 5 seventh aluminum foil is formed, wherein the method of impregnating and drying the conductive polymer dispersion liquid is as follows: the 5 sixth aluminum foil cathode regions are rotated at a speed of 15 r / min in the conductive polymer dispersion liquid with the metal shaft 2, the impregnation depth is 85% of the length of the cathode region, the impregnation time is 70 s, the drying temperature is 110 °C, and the drying time is 15 min.

[0087] S8, a conductive carbon slurry layer 17 is prepared by impregnating and drying a conductive carbon slurry on the surface of the 5 seventh aluminum foil cathode regions fixed on the metal shaft 2, and a 5 arch-shaped core 1 is formed, wherein the conductive carbon slurry layer is prepared by a method of impregnating and drying, and the method is as follows: the 5 seventh aluminum foil cathode regions are rotated at a speed of 7 r / min in the conductive carbon slurry with the metal shaft 2, the impregnation depth is 85% of the length of the cathode region, the impregnation time is 70 s, the drying temperature is 110 °C, and the drying time is 15 min.

[0088] S9, a conductive silver slurry layer is prepared by impregnating a conductive silver slurry on the cathode regions of the 5 arch-shaped cores 1 fixed on the metal shaft 2 and drying and solidifying, and an arch-shaped core body is formed, wherein the conductive silver slurry layer is prepared by a method of impregnating and drying, and the method is as follows: the cathode regions of the 5 arch-shaped cores 1 are rotated at a speed of 7 r / min in the conductive silver slurry with the metal shaft 2, the impregnation depth is 65% of the length of the cathode region, the impregnation time is 65 s, the drying temperature is 135 °C, and the drying time is 15 min. After drying, the conductive silver slurry covers the surface of the arch-shaped core body and fills the gaps between the cathode regions of the 5 arch-shaped cores 1, forming a circular silver slurry belt with a length equal to 65% of the total length of the cathode regions, and electrically connecting the cathode regions of the 5 arch-shaped cores 1.

[0089] S10, the part of the metal shaft 2 exposed outside the arch-shaped core body is completely cut off, and the part of the metal shaft 2 exposed outside the arch-shaped core body is kept at an appropriate length to obtain a protruding end 18, and a core package prototype 3 is formed.

[0090] S11, the external anode conductive frame 4 is electrically connected to the protruding end 18 in the core package prototype 3, and the external cathode conductive frame 5 is electrically connected to the cathode region of the surface where the protruding end 18 is located in the core package prototype 3, and a capacitor core package 6 is formed.

[0091] The anode lead frame 4 comprises an arc-shaped part 41, a first connecting part 42, a platform part 43, a second connecting part 44 and an L-shaped terminal part 45; the arc-shaped part 41 is sleeved on the outer wall of the protruding end 18 of the metal shaft 2, thereby realizing the electrical connection between the metal shaft 2 and the anode lead frame 4; the arc-shaped part 41 is connected with the platform part 43 through the first connecting part 42; the L-shaped terminal part 45 is connected with the platform part 43 through the second connecting part 44; the vertical part of the L-shaped terminal part 45 is aligned with and parallel to the chord part of the core package prototype 3 and faces the core package prototype 3; and the width of the L-shaped terminal part 45 is consistent with the width of the chord part of the core package prototype 3; the chord part is used as the anode of the product, and the anode and the cathode can be intuitively distinguished in appearance, thereby preventing the anode and the cathode from being reversely connected in the actual plate use of the capacitor and playing a foolproof role.

[0092] The cathode lead frame 5 comprises a planar tongue part 51, a connecting part 52 and an L-shaped terminal part 53; the planar tongue part 51 in the cathode lead frame 5 is adhered to the cathode area of the core package prototype 3 through conductive silver adhesive, thereby realizing the electrical connection; the L-shaped terminal part 53 is connected with the planar tongue part 51 through the connecting part 52; the horizontal part of the L-shaped terminal part 53 faces the same direction as the planar tongue part 51; and the vertical part of the L-shaped terminal part 53 is arranged on the outer side of the core package prototype 3 and faces the core package prototype 3.

[0093] The anode lead frame 4 and the cathode lead frame 5 are both integrally formed through punching and pressing of a planar metal strip.

[0094] S12, encapsulating the capacitor core package 6 with epoxy resin to form a resin shell 7 outside the capacitor core package 6, thereby obtaining the solid aluminum electrolytic capacitor 8.

[0095] Comparative Example One

[0096] S1, cutting the 3VF foil into a square with a width of 6.55 mm and a length of 12 mm to form a first aluminum foil;

[0097] S2, coating insulating glue on the first aluminum foil to divide the anode area and the cathode area, the length of the cathode area being 9.6 mm, thereby forming a second aluminum foil;

[0098] S3, repairing the dielectric layer on the side edge of the cathode area of the second aluminum foil through re-formation, thereby forming a third aluminum foil;

[0099] S4, preparing a first conductive polymer solid electrolyte layer on the surface of the cathode area of the third aluminum foil through a chemical polymerization method, thereby forming a fourth aluminum foil;

[0100] S5, preparing a second conductive polymer solid electrolyte layer on the surface of the cathode area of the fourth aluminum foil through an electrochemical polymerization method, thereby forming a fifth aluminum foil;

[0101] S6, preparing a conductive carbon paste layer on the surface of the cathode area of the fifth aluminum foil, thereby forming a sixth aluminum foil;

[0102] S7, guiding the surface of the sixth aluminum foil cathode region with a conductive silver paste layer to form a capacitor core;

[0103] S8, connecting the 5 capacitor cores with an external lead frame to form a capacitor core package;

[0104] S9, encapsulating the capacitor core package with epoxy resin, and bending the pins to form a square sheet type laminated solid aluminum electrolytic capacitor.

[0105] The sheet type laminated solid aluminum electrolytic capacitors prepared in the above comparative examples and examples are tested for electrical performance data, as shown in Table 1:

[0106] Table 1: Test electrical performance data of comparative examples and examples

[0107] Experimental groups Capacity (μF) ESR (mΩ) Cathode area ratio Example 2188.8 5.0 96％ Comparative example 1824.1 12.0 80％

[0108] From the electrical performance data of the above examples and comparative examples, it can be seen that compared with the comparative examples, the cathode region area ratio of the examples is significantly improved, and the capacitor capacity is larger and the ESR is smaller.

[0109] In the description of the present application, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inner", "front", "central", "both ends" and the like indicate the orientation or positional relationship based on the orientation or positional relationship of the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0110] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "setting", "connecting", "fixing", "threading" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited, the above-mentioned terms in the present application can be understood according to the specific meaning of the above-mentioned terms in the present application by those skilled in the art according to the specific circumstances.

[0111] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that modifications can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A chip-type multilayer solid aluminum electrolytic capacitor, characterized in that: It includes a capacitor core (6) and a resin shell (7), the resin shell (7) being encapsulated outside the capacitor core (6) to form a solid aluminum electrolytic capacitor (8). The capacitor core (6) includes a core core prototype (3), an anode lead frame (4), and a cathode lead frame (5). The core package prototype (3) includes an arc-shaped core body and a metal shaft (2), and the chords of several arc-shaped cores (1) in the arc-shaped core body are aligned. The bow-shaped core (1) includes a bow-shaped third aluminum foil (11), with a bow-shaped through hole (12) at the center of the third aluminum foil (11). The bow-shaped through hole (12) is vertically connected to a bow-shaped aluminum foil protrusion (13), and the bow-shaped aluminum foil protrusion (13) is connected to the first aluminum foil. The outer edge of the bow-shaped through hole (12) is coated with an annular insulating barrier tape (14). The area of ​​the third aluminum foil (11) outside the annular insulating barrier tape (14) is the cathode area, and the bow-shaped aluminum foil protrusion (13) is the anode area. The cathode area of ​​the bow-shaped core (1) is provided with a first conductive polymer solid electrolyte layer (15), a second conductive polymer solid electrolyte layer (16), and a conductive carbon paste layer (17) from the inside to the outside. The metal shaft (2) passes through the arc-shaped through holes (12) of several third aluminum foils (11) in sequence. The arc-shaped aluminum foil protrusions (13) of the third aluminum foils (11) are electrically connected to the metal shaft (2). After the arc-shaped core is prepared, the part of one end of the metal shaft (2) that is exposed outside the arc-shaped core is completely cut off, and the part of the other end of the metal shaft (2) that is exposed outside the arc-shaped core is retained to an appropriate length to form a protruding end (18). The anode lead frame (4) is electrically connected to the protruding end (18) of the metal shaft (2), and the cathode lead frame (5) is electrically connected to the cathode area of ​​the surface where the protruding end (18) is located.

2. The chip-type multilayer solid aluminum electrolytic capacitor according to claim 1, characterized in that: The central angle of the arc corresponding to the arc of the bow-shaped through hole (12) is between 270 degrees and 300 degrees, and the diameter of the bow-shaped through hole (12) is 10%-15% of the diameter of the first aluminum foil.

3. A chip-type multilayer solid aluminum electrolytic capacitor according to claim 1, characterized in that: The width of the annular insulating barrier tape (14) is 5%-10% of the diameter of the third aluminum foil (11), and the thickness of the annular insulating barrier tape (14) is 0.1mm-0.2mm.

4. A chip-type multilayer solid aluminum electrolytic capacitor according to claim 1, characterized in that: The distance between two adjacent third aluminum foils (11) on the metal shaft (2) is equal to the thickness of a single bow-shaped core (1).

5. A method for preparing a chip-type multilayer solid aluminum electrolytic capacitor according to any one of claims 1-4, characterized in that: The preparation method includes the following steps: S1. Cut the aluminum foil into an arc shape to form the first aluminum foil; S2. By cutting at the center of the first aluminum foil, an arc-shaped through hole (12) is obtained. The arc-shaped aluminum foil is connected to the first aluminum foil by the chord. The arc-shaped aluminum foil is bent at a right angle along the chord and the plane of the first aluminum foil to obtain the arc-shaped aluminum foil protrusion (13), forming the second aluminum foil. S3. Apply insulating barrier adhesive to both sides of the outer edge of the arc-shaped through hole (12) of the second aluminum foil to form an annular insulating barrier tape (14), dividing the anode area and the cathode area to form the third aluminum foil (11). S4. Pass the metal shaft (2) through the arc-shaped through holes (12) on several third aluminum foils (11), and electrically connect the arc-shaped aluminum foil protrusions (13) bent at right angles on each third aluminum foil (11) with the metal shaft (2) to form several fourth aluminum foils fixed on the metal shaft (2). S5. The side dielectric layer of several fourth aluminum foils fixed on the metal shaft (2) is reformed and repaired to form several fifth aluminum foils fixed on the metal shaft (2). S6. A first conductive polymer solid electrolyte layer (15) is prepared on the cathode area surface of several fifth aluminum foils fixed on the metal shaft (2) by chemical polymerization, forming several sixth aluminum foils fixed on the metal shaft (2). S7. A second conductive polymer solid electrolyte layer (16) is prepared on the cathode area surface of several sixth aluminum foils fixed on the metal shaft (2) by impregnation with conductive polymer dispersion and drying, thereby forming several seventh aluminum foils fixed on the metal shaft (2). S8. Conductive carbon paste is prepared and dried on the cathode area surface of several seventh aluminum foils fixed on the metal shaft (2) to obtain a conductive carbon paste layer (17) and form several bow-shaped cores (1) fixed on the metal shaft (2). S9. Immerse the cathode region of several arc-shaped cores (1) fixed on the metal shaft (2) into conductive silver paste, and dry and solidify them to obtain a conductive silver paste layer, forming an arc-shaped core body fixed on the metal shaft (2); S10. Cut off the part of one end of the metal shaft (2) that is outside the bow-shaped core, and keep the part of the other end of the metal shaft (2) that is outside the bow-shaped core for an appropriate length to obtain the protruding end (18), forming the core package prototype (3). S11. Connect the external anode lead frame (4) to the protruding end (18) of the core package prototype (3) electrically, and connect the external cathode lead frame (5) to the cathode area on the surface where the protruding end (18) of the core package prototype (3) is located, to form a capacitor core package (6). S12. The capacitor core (6) is encapsulated with epoxy resin to form a resin shell (7) outside the capacitor core, thus obtaining a solid aluminum electrolytic capacitor (8).

6. The method for preparing a chip-type multilayer solid aluminum electrolytic capacitor according to claim 5, characterized in that: In step S5, the re-formation repair of the side dielectric layer is carried out by immersion in the formation solution and electroforming. The specific method is as follows: a metal shaft (2) drives several fourth aluminum foil cathode areas to rotate at a constant speed in the formation solution, with a rotation speed of 5r / min-30r / min, an immersion depth of the entire cathode area, and an electroforming time of 20min-100min.

7. The method for preparing a chip-type multilayer solid aluminum electrolytic capacitor according to claim 5, characterized in that: The chemical polymerization method in step S6 is carried out by alternating immersion in oxidizing solution and reducing solution and drying. The specific method is as follows: a metal shaft (2) drives several fifth aluminum foil cathode areas to rotate at a constant speed in oxidizing solution or reducing solution, with a rotation speed of 5r / min-30r / min, an immersion depth of the entire cathode area, and an immersion time of 60S-120S.

8. The method for preparing a chip-type multilayer solid aluminum electrolytic capacitor according to claim 5, characterized in that: The method of impregnating and drying the conductive polymer dispersion in step S7 is as follows: a metal shaft (2) drives several sixth aluminum foil cathode areas to rotate at a constant speed in the conductive polymer dispersion. The rotation speed is 5r / min-10r / min, the impregnation depth is such that the entire cathode area is completely submerged, the impregnation time is 60S-120S, the drying temperature is 40℃-75℃, and the drying time is 2min-10min.

9. The method for preparing a chip-type multilayer solid aluminum electrolytic capacitor according to claim 5, characterized in that: The method for preparing and drying the conductive carbon slurry in step S8 is as follows: a metal shaft (2) drives several seventh aluminum foil cathode areas to rotate uniformly in the conductive carbon slurry at a speed of 5r / min-10r / min, the immersion depth is 80%-90% of the length of the entire cathode area, the immersion time is 60S-120S, the drying temperature is 80℃-130℃, and the drying time is 10min-30min.

10. The method for preparing a chip-type multilayer solid aluminum electrolytic capacitor according to claim 5, characterized in that: The method for preparing the conductive silver paste layer in step S9 is as follows: a metal rotating shaft (2) drives several arched cores (1) cathode areas to rotate uniformly in the conductive silver paste at a speed of 5r / min-10r / min, the immersion depth is 60%-70% of the length of the entire cathode area, the immersion time is 60S-120S, the drying temperature is 80℃-150℃, and the drying time is 10min-30min.

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