High-temperature-resistant laminated solid aluminum electrolytic capacitor and preparation method thereof

Abstract

A high-temperature-resistant laminated solid aluminum electrolytic capacitor comprises a core and a sealing assembly, and the core is arranged in the sealing assembly. The core comprises a plurality of single sheets which are stacked together; each single chip comprises an anode end, a cathode end and a shielding glue line located between the anode end and the cathode end; the cathode end of each single chip sequentially comprises an aluminum foil, an oxidation film layer and a conductive high-molecular polymer layer doped with a dopant from inside to outside; the doping agent comprises at least one of alkyl benzene sulfonic acid and salt thereof, alkyl naphthalene sulfonic acid and salt thereof, and quinonesulfonic acid and salt thereof. According to the invention, the addition of the dopant can improve the density of the conductive high-molecular polymer after crosslinking; meanwhile, the doping agent can improve and reinforce the net structure of the conductive high-molecular polymer, so that the thermal stability of the conductive high-molecular polymer is improved, and the conductive high-molecular polymer can keep the physical and mechanical properties basically unchanged even under a high-temperature condition; therefore, the high temperature resistance of the laminated solid aluminum electrolytic capacitor is improved.

Description

Technical Field

[0001] The invention relates to an aluminum electrolytic capacitor, and in particular to a high-temperature resistant laminated solid aluminum electrolytic capacitor and a preparation method thereof. Background Art

[0002] The laminated solid aluminum electrolytic capacitor uses solid conductive polymer instead of liquid electrolyte, and the core is connected in parallel in a stacked manner. Compared with liquid aluminum electrolytic capacitors, the manufactured capacitor has many advantages such as smaller size, smaller equivalent series resistance (ESR), wider temperature range and more environmental protection. It conforms to the development trend of miniaturization and high frequency of electronic products and meets the requirements of surface mount technology (SMT).

[0003] Although the existing process can prepare laminated solid aluminum electrolytic capacitors with better performance, such as the high-humidity resistant laminated aluminum electrolytic capacitor and its manufacturing method disclosed in patent CN113658805A, the service life is short in high temperature environment and cannot meet the life requirements for high temperature application environment. 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 high temperature resistant laminated solid aluminum electrolytic capacitor and a preparation method thereof.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: a high temperature resistant laminated solid aluminum electrolytic capacitor, comprising a core and a sealing assembly, wherein the core is arranged in the sealing assembly; the core comprises a plurality of single sheets stacked together; the single sheet comprises an anode terminal, a cathode terminal and a shielding rubber wire located between the anode terminal and the cathode terminal; the cathode terminal of the single sheet comprises, from the inside to the outside, an aluminum foil, an oxide film layer and a conductive high molecular polymer layer doped with a dopant; the dopant comprises at least one of alkyl benzene sulfonic acid and its salt, alkyl naphthalene sulfonic acid and its salt, and quinone structure sulfonic acid and its salt.

[0006] In the above-mentioned high temperature resistant laminated solid aluminum electrolytic capacitor, preferably, the monomer of the conductive high molecular polymer includes at least one of thiophene, pyrrole, aniline and their derivatives.

[0007] In the above-mentioned high temperature resistant laminated solid aluminum electrolytic capacitor, preferably, the weight of the dopant is 0.01%-8% of the total weight of the conductive high molecular polymer.

[0008] A method for preparing a high temperature resistant laminated solid aluminum electrolytic capacitor comprises the following steps: 1) Weld the cut aluminum foil to the iron bar; 2) Apply insulating barrier glue on the welded aluminum foil to divide the anode area and cathode area; 3) Immerse the cathode area in the electrolyte and apply electricity to repair the oxide film on the surface of the cathode area; 4) Immerse the cathode area after step 3) in an oxidant solution, in which a dopant is added; after being taken out, dry it at a temperature of 60-100°C, and then immerse it in a monomer solution; after being taken out, react it in a constant temperature and humidity chamber, then wash away the excess residual liquid with a cleaning liquid, and put it in an oven to dry, so as to form a conductive polymer layer on the surface of the cathode area; 5) forming a conductive graphite layer on the outer surface of the conductive polymer cathode layer; 6) A conductive silver paste layer is formed on the outer surface of the conductive graphite layer to form a single sheet.

[0009] In the above-mentioned method for preparing the high-temperature resistant laminated solid aluminum electrolytic capacitor, preferably, the oxidant includes at least one of ferric p-toluenesulfonate, potassium permanganate, potassium perchlorate, ammonium persulfate, potassium persulfate, sodium persulfate, ferric chloride, and hydrogen peroxide; and the weight concentration of the oxidant in the oxidant solution is 10%-60%.

[0010] In the above-mentioned method for preparing the high temperature resistant laminated solid aluminum electrolytic capacitor, preferably, the weight concentration of the dopant in the oxidant solution is 0.5%-8%.

[0011] In the above-mentioned method for preparing the high temperature resistant laminated solid aluminum electrolytic capacitor, preferably, the monomer comprises at least one of thiophene, pyrrole, aniline and their derivatives; and the weight concentration of the monomer in the monomer solution is 0.5%-40%.

[0012] Compared with the prior art, the advantages of the present invention are: in the present invention, the addition of the dopant can increase the density of the conductive polymer after cross-linking; at the same time, the dopant can improve and strengthen the network structure of the conductive polymer, thereby improving the thermal stability of the conductive polymer, and even under high temperature conditions, the conductive polymer can maintain its physical and mechanical properties basically unchanged; thereby improving the high temperature resistance of the laminated solid aluminum electrolytic capacitor. DETAILED DESCRIPTION

[0013] 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.

[0014] 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.

[0015] 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.

[0016] A high temperature resistant laminated solid aluminum electrolytic capacitor comprises a core and a sealing component, wherein the core is arranged in the sealing component; the core comprises a plurality of laminated monoliths; the monoliths comprise an anode terminal, a cathode terminal and a shielding rubber wire located between the anode terminal and the cathode terminal; the cathode terminal of the monoliths comprises aluminum foil, an oxide film layer and a conductive high molecular polymer layer doped with a dopant from the inside to the outside. The dopant comprises at least one of alkyl benzene sulfonic acid and its salt, alkyl naphthalene sulfonic acid and its salt, and quinone structure sulfonic acid and its salt; the monomer of the conductive high molecular polymer comprises at least one of thiophene, pyrrole, aniline and its derivatives; the weight of the dopant is 0.01%-8% of the total weight of the conductive high molecular polymer.

[0017] This embodiment also provides a method for preparing a high temperature resistant laminated solid aluminum electrolytic capacitor, comprising the following steps: 1) Weld the cut aluminum foil to the iron bar.

[0018] 2) Apply insulating barrier glue on the welded aluminum foil to divide the anode area and cathode area.

[0019] 3) Immerse the cathode area in the electrolyte and apply electricity to chemically repair the oxide film on the surface of the cathode area.

[0020] 4) Immerse the cathode area after completing step 3) in an oxidant solution to which a dopant is added; after taking it out, dry it at a temperature of 60-100°C, and then immerse it in a monomer solution; after taking it out, react it in a constant temperature and humidity chamber, then wash away the excess residual liquid with a cleaning liquid, and put it in an oven to dry, so as to form a conductive polymer layer on the surface of the cathode area.

[0021] The oxidant includes at least one of ferric p-toluenesulfonate, potassium permanganate, potassium perchlorate, ammonium persulfate, potassium persulfate, sodium persulfate, ferric chloride, and hydrogen peroxide; the weight concentration of the oxidant in the oxidant solution is 10%-60%. The weight concentration of the dopant in the oxidant solution is 0.5%-8%. The monomer includes at least one of thiophene, pyrrole, aniline and their derivatives; the weight concentration of the monomer in the monomer solution is 0.5%-40%.

[0022] 5) A conductive graphite layer is formed on the outer surface of the conductive polymer cathode layer.

[0023] 6) A conductive silver paste layer is formed on the outer surface of the conductive graphite layer to form a single sheet. Example

[0024] This embodiment provides a high temperature resistant laminated solid aluminum electrolytic capacitor, including a core and a sealing assembly, wherein the core is arranged in the sealing assembly; the core includes a plurality of laminated sheets; the sheet includes an anode terminal, a cathode terminal, and a shielding rubber wire located between the anode terminal and the cathode terminal; the cathode terminal of the sheet includes aluminum foil, an oxide film layer, and a conductive polymer layer doped with a dopant from the inside to the outside; the dopant is disodium methylenebisnaphthalenesulfonate; the monomer of the conductive polymer is thiophene. The weight of the dopant is 0.01%-8% of the total weight of the conductive polymer.

[0025] This embodiment also provides a method for manufacturing a high temperature resistant laminated solid aluminum electrolytic capacitor, comprising the following steps: 1) Select 3.6VF aluminum foil, cut it and weld it to the iron bar; the cutting width is 3.55mm and the length is 13mm; 2) Apply insulating barrier glue on the welded aluminum foil to divide the anode area and cathode area; the length of the cathode area is 5.2mm.

[0026] 3) Immerse the cathode area in the electrolyte and apply electricity to repair the oxide film on the surface of the cathode area; 4) Immerse the cathode area after completing step 3) in an oxidant solution, in which a dopant is added; after taking it out, dry it at 80°C, and then immerse it in a monomer solution; after taking it out, react it in a constant temperature and humidity box at 80°C and 60%, then wash away the excess residual liquid with a cleaning liquid, put it in an oven and dry it, and form a conductive polymer layer on the surface of the cathode area; this is one cycle, and repeat 8 cycles continuously. The cleaning liquid can be one or more of pure water, methanol, ethanol, dimethylformamide, butanol, etc. In this embodiment, the oxidant is a 25% by weight concentration of iron p-toluenesulfonate solution, and the dopant is a 5% by weight concentration of methylenebisnaphthalenesulfonic acid disodium salt.

[0027] 5) Forming a conductive graphite layer on the outer surface of the conductive polymer cathode layer. The specific method is to immerse the cathode area prepared in step 4) into the conductive graphite slurry for 12 seconds, slowly lift it out of the slurry, and dry it; that is, a conductive graphite layer is formed on the conductive polymer layer.

[0028] 6) Slowly immerse the cathode area prepared in step 5) into the conductive silver paste for 12 seconds, slowly lift it out of the paste and dry it to form a single piece.

[0029] 7) Multiple single-chip anode areas are welded to the anode area of ​​the lead frame, and the cathode area is glued by array dispensing, with a glue dot of 2 mm in diameter, which is extruded and solidified to form a laminated core.

[0030] 8) Apply conductive silver paste to the cathode area of ​​the laminated core so that the cathode areas of the single piece are electrically connected together; after drying, the final core is formed. Example

[0031] The difference from Example 1 is that the mass ratio of iron p-toluenesulfonate in step 4) is 35% Example

[0032] The difference from Example 1 is that the mass ratio of methylenebisnaphthalenesulfonic acid disodium salt in step 4) is 2%. Example

[0033] The difference from Example 1 is that the temperature and humidity of the constant temperature and humidity chamber in step 4) is 30°C / 40% Example

[0034] Different from Example 1, the mass ratio of thiophene monomer in step 4) is 20% Example

[0035] The difference from Example 1 is that the monomer in step 4) is 15% pyrrole Comparative Example 1 The difference from Example 1 is that the doping agent is 5% disodium methylenebisnaphthalenesulfonate. Comparative Example 2 The difference from Example 1 is that the use of pure water to wash away the excess oxidant at the bottom is eliminated. Comparative Example 3 The difference from Example 1 is that methanol is not used to wash away the excess residual liquid. The above examples 1-6 and comparative examples 1-3 were used to make 2.5V 470μF capacitors, and the initial capacity (CAP), loss (DF), equivalent series resistance (ESR), and leakage value (LC) of the capacitors were tested. Then they were subjected to a high temperature load of 125°C for 1000 hours, and the data are shown in Table 1: Table 1 Comparison of 125℃ high temperature load performance of capacitors in the embodiment and comparative example

[0036] From the data in Table 1 above, it can be seen that the initial ESR performance of Examples 1 to 6 is significantly reduced. After 1000 hours of high temperature load at 125°C, the CAP attenuation is less than that of the comparative example, the DF change is less than that of the comparative example, the ESR change is less than that of the comparative example, and the LC change is less than that of the comparative example. Examples 1-6 have significantly improved the high temperature resistance of the product.

Claims

1. A high temperature resistant laminated solid aluminum electrolytic capacitor, comprising a core and a sealing assembly, wherein the core is arranged in the sealing assembly; the core comprises a plurality of single sheets stacked together; the single sheet comprises an anode terminal, a cathode terminal and a shielding rubber wire located between the anode terminal and the cathode terminal; characterized in that: The cathode end of the monolithic sheet includes aluminum foil, an oxide film layer and a conductive high polymer layer doped with a dopant from the inside to the outside; the dopant includes at least one of alkyl benzene sulfonic acid and its salt, alkyl naphthalene sulfonic acid and its salt, and quinone structure sulfonic acid and its salt.

2. The high temperature resistant laminated solid aluminum electrolytic capacitor according to claim 1, characterized in that: The monomers of the conductive high molecular polymer include at least one of thiophene, pyrrole, aniline and their derivatives.

3. The high temperature resistant laminated solid aluminum electrolytic capacitor according to claim 1, characterized in that: The weight of the dopant is 0.01%-8% of the total weight of the conductive high molecular polymer.

4. A method for preparing a high temperature resistant laminated solid aluminum electrolytic capacitor, characterized in that: The following steps are included: 1) Weld the cut aluminum foil to the iron bar; 2) Apply insulating barrier glue on the welded aluminum foil to divide the anode area and cathode area; 3) Immerse the cathode area in the electrolyte and apply electricity to repair the oxide film on the surface of the cathode area; 4) Immerse the cathode area after step 3) in an oxidant solution, in which a dopant is added; after being taken out, dry it at a temperature of 60-100°C, and then immerse it in a monomer solution; after being taken out, react it in a constant temperature and humidity chamber, then wash away the excess residual liquid with a cleaning liquid, and put it in an oven to dry, so as to form a conductive polymer layer on the surface of the cathode area; 5) forming a conductive graphite layer on the outer surface of the conductive polymer cathode layer; 6) A conductive silver paste layer is formed on the outer surface of the conductive graphite layer to form a single sheet.

5. The method for preparing a high temperature resistant laminated solid aluminum electrolytic capacitor according to claim 4, characterized in that: The oxidant comprises at least one of ferric p-toluenesulfonate, potassium permanganate, potassium perchlorate, ammonium persulfate, potassium persulfate, sodium persulfate, ferric chloride and hydrogen peroxide; the weight concentration of the oxidant in the oxidant solution is 10%-60%.

6. The method for preparing a high temperature resistant laminated solid aluminum electrolytic capacitor according to claim 4, characterized in that: The weight concentration of the dopant in the oxidant solution is 0.5%-8%.

7. The method for preparing a high temperature resistant laminated solid aluminum electrolytic capacitor according to claim 4, characterized in that: The monomer comprises at least one of thiophene, pyrrole, aniline and derivatives thereof; the weight concentration of the monomer in the monomer solution is 0.5%-40%.

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