A solid aluminum electrolytic capacitor and a method for preparing the same

Abstract

A solid aluminum electrolytic capacitor comprises an anode foil, an electrolytic paper and a cathode foil, wherein the anode foil, the electrolytic paper and the cathode foil are wound into a core package, and an anode guide pin and a cathode guide pin are riveted to the anode foil and the cathode foil respectively, and a foil is covered at the part where the anode guide pin and the cathode guide pin are riveted to the anode foil and the cathode foil; the foil completely covers the positive electrode guide pin or the cathode guide pin on the anode foil or the cathode foil; and a layer of PEDOT:PSS polymer doped with methylimidazole is formed between the anode foil and the cathode foil. In the present invention, the mechanical properties of the solid aluminum electrolytic capacitor are improved in two aspects: first, the contact area between the anode guide pin and the cathode guide pin and the high molecular conductive polymer layer is increased by the foil, and second, the PEDOT:PSS polymer film is structurally optimized by methylimidazole, so that the PEDOT:PSS polymer film has better flexibility, thereby the mechanical properties of the solid aluminum electrolytic capacitor are better.

Description

Technical Field

[0001] The present invention relates to a capacitor, and in particular to a solid aluminum electrolytic capacitor and a preparation method thereof. Background Art

[0002] In the existing preparation method of the charge-discharge resistant solid aluminum electrolytic capacitor, in order to obtain a charge-discharge resistant solid aluminum electrolytic capacitor with high withstand voltage and low leakage current, the core package is impregnated with PEDT:PSS dispersion. For example, patent CN105826076A, a new solid capacitor and its production method, discloses that the core package that is dried after formation and polymerization is immersed in a conductive polymer dispersion, and then subjected to high-temperature drying treatment, sealing assembly and aging processes, so as to obtain a charge-discharge resistant solid aluminum electrolytic capacitor.

[0003] We all know that solid aluminum electrolytic capacitors have poor mechanical properties due to their solid electrolytes. They are not suitable for use in a shaking environment because when shaking, the anode and cathode guide pins are subjected to force, which will exert a tiny force on the core package. Under the action of this tiny force, the structure of the high molecular conductive polymer at the anode and cathode guide pins is very easy to be damaged, resulting in tiny cracks, which causes electrical performance problems in the solid aluminum electrolytic capacitor. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a solid aluminum electrolytic capacitor with significantly improved mechanical properties and a preparation method thereof.

[0005] In order to solve the above technical problems, the technical solution proposed in the present invention is: a solid aluminum electrolytic capacitor, comprising an anode foil, an electrolytic paper and a cathode foil, wherein the anode foil, the electrolytic paper and the cathode foil are wound into a core package, and the anode foil and the cathode foil are riveted with an anode guide pin and a cathode guide pin respectively, and the anode guide pin and the cathode guide pin are covered with a foil at the position where the anode guide pin and the cathode guide pin are riveted to the anode foil and the cathode foil; the foil completely covers the positive electrode guide pin or the cathode guide pin on the anode foil or the cathode foil; and a layer of PEDOT:PSS polymer doped with methylimidazole is formed between the anode foil and the cathode foil.

[0006] For the above-mentioned solid aluminum electrolytic capacitor, preferably, the thickness of the foil is no more than half of the thickness of the anode foil; the length of the foil is 2 to 5 times the width of the riveted portion between the anode guide pin or cathode guide pin and the anode foil or cathode foil.

[0007] In the above-mentioned solid aluminum electrolytic capacitor, preferably, the connection between the foil and the anode foil or the cathode foil is cold-pressed riveting.

[0008] In the above-mentioned solid aluminum electrolytic capacitor, preferably, the electrolytic paper is carbonized electrolytic paper.

[0009] In the above-mentioned solid aluminum electrolytic capacitor, preferably, the positions of the anode guide pin and the cathode guide pin on the core package are staggered.

[0010] A method for preparing a solid aluminum electrolytic capacitor comprises the following steps: 1) riveting an anode guide pin and a cathode guide pin to an anode foil and a cathode foil respectively;

[0011] 2) Cover the part where the anode guide pin and cathode guide pin are riveted to the anode foil and cathode foil by cold riveting;

[0012] 3) Winding the electrolytic paper, the anode foil and the cathode foil of step 2) into a core package;

[0013] 4) immersing the core obtained in step 3) in a dispersion comprising 80-95 parts by weight of PEDOT:PSS, 2-10 parts by weight of ethylene glycol, 20-10 parts by weight of ethanol and 5-15 parts by weight of methylimidazole solution;

[0014] 5) Dry the core package at a temperature of 60-90 degrees Celsius;

[0015] 6) Assembly and packaging.

[0016] In the preparation method of the above-mentioned solid aluminum electrolytic capacitor, preferably, a formation step is further provided before step 3) and step 4), and the formation step includes a low-voltage product formation process and a high-voltage product formation process. The formation liquid of the low-voltage product formation process is phosphoric acid, the conductivity of the formation liquid is 2.2-2.6 mS / cm, the pH value of the formation liquid is 2.9-3.3, the formation time is 30-33min, the formation temperature is 60-70°C, the formation voltage is 9.5-10.3V, and the initial current is 4.5-5mA / pcs; the formation liquid of the high-voltage product formation process is an ammonium adipate solution, the conductivity of the formation liquid is 9-11mS / cm, and the pH value of the formation liquid is 2.9-3.3. The formation time is 6.5-7.5, the formation time is 50-60min, the formation temperature is 45-55℃, the formation voltage is 20V-40V-60V-73V and gradually increases, the formation time in the 20V, 40V, and 60V voltage sections is 10min, the formation time in the 73V voltage section is 20min, and the initial formation current is 5-5.5mA / pcs.

[0017] In the above-mentioned method for preparing the solid aluminum electrolytic capacitor, preferably, the positions of the anode guide pin and the cathode guide pin are staggered when winding into the core package.

[0018] Compared with the prior art, the advantages of the present invention are as follows: in the present invention, the mechanical properties of the solid aluminum electrolytic capacitor are improved in two aspects: first, the contact area between the anode guide pin and the cathode guide pin and the high molecular conductive polymer layer is increased by pasting foil, and second, the structure of the PEDOT:PSS polymer film is optimized by methylimidazole, so that the PEDOT:PSS polymer film has better flexibility, thereby improving the mechanical properties of the solid aluminum electrolytic capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the foil attached to the anode foil in Example 1.

[0020] Figure 2 This is the SEM image of the methylimidazole-doped PEDOT:PSS polymer film in Example 1.

[0021] Legend

[0022] 1. Anode foil; 2. Anode guide pin; 3. Foil pasting. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0024] It should be noted that when an element is described as being "fixed, fixed, connected or connected to" another element, it can be directly fixed, fixed, connected or connected to the other element, or it can be indirectly fixed, fixed, connected or connected to the other element through other intermediate connectors.

[0025] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0026] Example 1

[0027] A solid aluminum electrolytic capacitor comprises an anode foil, an electrolytic paper and a cathode foil, wherein the anode foil, the carbonized electrolytic paper and the cathode foil are wound into a core package, and an anode guide pin and a cathode guide pin are riveted to the anode foil and the cathode foil respectively. Figure 1 The position where the anode guide pin and the cathode guide pin are riveted to the anode foil and the cathode foil is covered with a foil; the foil completely covers the positive electrode guide pin or the cathode guide pin on the anode foil or the cathode foil; a layer of PEDOT:PSS polymer doped with methylimidazole is formed between the anode foil and the cathode foil.

[0028] In this embodiment, the thickness of the foil is half of the thickness of the anode foil; the length of the foil is 5 times the width of the riveted portion between the anode guide pin or cathode guide pin and the anode foil or cathode foil.

[0029] The connection between the foil and the anode foil or cathode foil is cold riveting.

[0030] In this embodiment, the positions of the anode guide pin and the cathode guide pin on the core package are staggered.

[0031] A method for preparing a solid aluminum electrolytic capacitor comprises the following steps: 1) riveting an anode guide pin and a cathode guide pin to an anode foil and a cathode foil respectively;

[0032] 2) Cover the part where the anode guide pin and cathode guide pin are riveted to the anode foil and cathode foil by cold riveting;

[0033] 3) Winding the electrolytic paper, the anode foil and the cathode foil of step 2) into a core package;

[0034] 4) immersing the core obtained in step 3) in a dispersion comprising 90 parts by weight of PEDOT:PSS, 5 parts by weight of ethylene glycol, 5 parts by weight of ethanol and 10 parts by weight of methylimidazole solution;

[0035] 5) Dry the core package at a temperature of 60-90 degrees Celsius;

[0036] 6) Assembly and packaging.

[0037] In this embodiment, a formation step is provided before step 3) and step 4), and the formation liquid of the formation process for forming a low-pressure product is phosphoric acid, the conductivity of the formation liquid is 2.2-2.6 mS / cm, the pH value of the formation liquid is 2.9-3.3, the formation time is 30-33 min, the formation temperature is 60-70° C., the formation voltage is 9.5-10.3 V, and the initial formation current is 4.5-5 mA / pcs.

[0038] In other embodiments, the forming liquid of the forming process of the high voltage product is an ammonium adipate solution, the conductivity of the forming liquid is 9-11mS / cm, the pH of the forming liquid is 6.5-7.5, the forming time is 50-60min, the forming temperature is 45-55°C, the forming voltage is 20V-40V-60V-73V and gradually increases, the forming time of 20V, 40V, 60V voltage sections is 10min, the forming time of 73V voltage section is 20min, and the initial current of the forming is 5-5.5mA / pcs. Because the oxide film of the high voltage product is thick and the porosity on the oxide film is low, the forming process is completely different.

[0039] The SEM scanning image of the anode foil of the solid aluminum electrolytic capacitor prepared in this embodiment is as follows: Figure 2As shown, in Figure 2 It can be seen that the high molecular conductive polymer is evenly attached to the anode foil. The PEDOT:PSS polymer doped with methylimidazole is dense, smooth, and has no voids. The methylimidazole is evenly dispersed in the PEDOT:PSS polymer, making the PEDOT:PSS polymer film more flexible, thereby improving the mechanical properties of the solid aluminum electrolytic capacitor.

[0040] For comparison, we compared it with traditional capacitors, which are solid capacitors without foil and doped with methylimidazole. We fixed the anode guide pins and cathode guide pins of the two capacitors on the circuit board. Under the same vibration conditions, the yield of the solid aluminum electrolytic capacitor in this embodiment is 3.6 percentage points higher than that of the traditional capacitor.

Claims

1. A method for preparing a solid aluminum electrolytic capacitor, characterized in that: The following steps are involved: 1) Rivet the anode guide pin and cathode guide pin to the anode foil and cathode foil respectively; 2) Cover the part where the anode guide pin and cathode guide pin are riveted to the anode foil and cathode foil by cold riveting; 3) Winding the electrolytic paper, the anode foil and the cathode foil of step 2) into a core package; 4) immersing the core obtained in step 3) in a dispersion comprising 90 parts by weight of PEDOT:PSS, 5 parts by weight of ethylene glycol, 5 parts by weight of ethanol and 10 parts by weight of methylimidazole solution; 5) Dry the core package at a temperature of 60-90 degrees Celsius; 6) Assembly and packaging; forming a solid aluminum electrolytic capacitor; Before step 3), a chemical formation step is also provided, and the chemical formation step includes a low-pressure product chemical formation process or a high-pressure product chemical formation process. The chemical formation liquid of the low-pressure product chemical formation process is phosphoric acid, the conductivity of the chemical formation liquid is 2.2-2.6 mS / cm, the pH value of the chemical formation liquid is 2.9-3.3, the chemical formation time is 30-33min, the chemical formation temperature is 60-70°C, the chemical formation voltage is 9.5-10.3V, and the initial current of the chemical formation is 4.5-5mA / pcs; the chemical formation liquid of the high-pressure product chemical formation process is ammonium adipate solution, the conductivity of the chemical formation liquid is 9-11mS / cm, the pH value of the chemical formation liquid is 2.9-3.3, the chemical formation time is 30-33min, the chemical formation temperature is 60-70°C, the chemical formation voltage is 9.5-10.3V, and the initial current of the chemical formation is 4.5-5mA / pcs. The formation time is 6.5-7.5, the formation time is 50-60min, the formation temperature is 45-55℃, the formation voltage is 20V-40V-60V-73V and gradually increases, the formation time in the 20V, 40V, and 60V voltage sections is 10min, the formation time in the 73V voltage section is 20min, and the initial formation current is 5-5.5mA / pcs.

2. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: When winding into a core package, the positions of the anode guide needle and the cathode guide needle are staggered.

3. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: The solid aluminum electrolytic capacitor comprises an anode foil, an electrolytic paper and a cathode foil, wherein the anode foil, the electrolytic paper and the cathode foil are wound into a core package, the anode foil and the cathode foil are riveted with an anode guide pin and a cathode guide pin respectively, and the riveted parts of the anode guide pin and the cathode guide pin and the anode foil and the cathode foil are covered with a foil; the foil completely covers the positive electrode guide pin or the cathode guide pin on the anode foil or the cathode foil; and a layer of PEDOT:PSS polymer doped with methylimidazole is formed between the anode foil and the cathode foil.

4. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: The thickness of the foil is no more than half of the thickness of the anode foil; the length of the foil is 2 to 5 times the width of the riveted part between the anode guide pin and the anode foil, or 2 to 5 times the width of the riveted part between the cathode guide pin and the cathode foil.

5. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: The electrolytic paper is carbonized electrolytic paper.

Images