CN112053851B - A solid electrolytic capacitor with silver paste cathode - Google Patents

Abstract

The present invention provides a solid electrolytic capacitor containing a silver paste cathode. The cathode of the capacitor is an integrated silver-coated inner core. The inner core also includes a silver paste solidified layer covering the outer wall of the inner core; the preparation method of the silver paste solidified layer is as follows: firstly injecting silver paste into the mold with the inner core and vibrating the mold at high frequency, and then using a high temperature The silver paste in the mold is solidified to form an integrated silver-coated inner core; the invention has the advantages of being convenient for mass production, improving the ESR performance and life of the device, and the like.

Description

A solid electrolytic capacitor with silver paste cathode

technical field

The invention relates to the technical field of electronic component manufacturing, in particular to a solid electrolytic capacitor containing a silver paste cathode.

Background technique

The market demand for high-end capacitors is gradually trending towards high reliability, low ESR (equivalent series resistance), miniaturization and large capacity, especially for stacked solid electrolytic capacitors, which in turn form dielectrics and conductive polymers on the surface of high-purity aluminum foils as electrolytes , Cathode extraction layer. The lead-out element anode is connected to the anode of the lead frame by welding, and the element cathode is connected to the cathode of the lead frame through conductive glue to form a laminated core. It functions to protect the inner core. In the production process of solid electrolytic capacitors, it is necessary to perform silver paste work on the cathode of the solid electrolytic capacitor core.

The disadvantage of the prior art is: because the impregnation method realizes the silver-containing cathode layer of a single element, but the stacking structure realizes the parallel connection between the layers and requires a conductive silver paste method. The effect of the one-piece silver paste after curing is comparable, which makes it difficult for the product to achieve ultra-low ESR, and the ESR is normally distributed and dispersed, which makes it difficult to meet the demand for ultra-low ESR in the high-frequency application field of the product, and also restricts the product in the high-performance field. application, because the adhesion interface is easy to physically detach during the assessment process, resulting in the deterioration of ESR performance. The technical problem to be solved by the present invention is to provide a method for preparing a silver paste cathode, which can effectively solve the defects of the existing silver paste impregnation technology and the silver paste lamination method, and has the advantages of being convenient for mass production, improving the ESR performance and life of the device, etc. .

SUMMARY OF THE INVENTION

The present invention provides a solid electrolytic capacitor containing a silver paste cathode, which has the advantages of being convenient for mass production, improving the ESR performance and service life of the device, and the like.

The present invention adopts the following technical solutions.

A solid electrolytic capacitor containing a silver paste cathode, the cathode of the capacitor is an integrated silver-coated inner core, and the silver-coated inner core comprises an inner core formed by stacking multiple layers of elements treated with pre-impregnated silver paste, It also includes a silver paste solidified layer covering the outer wall of the inner core; the preparation method of the silver paste solidified layer is as follows: firstly injecting silver paste into a mold with a built-in inner core and vibrating the mold with high frequency, and then using a high temperature to irrigate the inside of the mold. The silver paste is solidified to form an integrated silver-coated inner core.

The preparation process of the capacitor includes an element processing process and an element stacking process;

The element processing procedure includes:

Step A1, forming an oxide film on the surface of the capacitor anode material so that it can be used as an oxide film dielectric material;

Step A2, using a barrier glue to divide the capacitor cathode area and the anode area at the oxide film dielectric material;

Step A3, forming a conductive polymer as a solid electrolyte layer on the outer surface of the cathode region of the oxide film dielectric material;

Step A4, forming a conductive carbon cathode layer on the outer surface of the electrolyte layer;

Step A5, forming a conductive silver cathode layer on the outer surface of the conductive carbon cathode layer to shape the silver-containing conductive cathode;

The element stacking process includes:

Step B1, compressing each layer of elements to form an inner core with a laminated structure;

Step B2, connecting the anodes of the plurality of elements and the anodes of the lead frame by welding;

Step B3, using a mold to inject silver paste to solidify the inner core into an integrated silver-coated inner core;

Step B4, encapsulating the cured integrated silver-coated inner core.

The method used in the step A5 includes the method of pre-impregnating the element with the conductive carbon cathode layer with a silver content of 45-65% silver paste;

The method used in the step B1 includes the method of placing the lead frame cathode workpiece in the middle of the elements when stacking the elements layer by layer, so as to sandwich the lead frame cathode workpiece in the middle of the stacked structure.

The mold is provided with a rectangular mold cavity, and the top of the mold is provided with an injection port;

When performing step B3, first place the inner core in the mold cavity, then inject silver paste with a silver content of 35-55% into the mold cavity from the top injection port of the mold, and use high-frequency vibration technology to vibrate the mold. The silver paste injected into the mold cavity can fill the gap between the elements and the space between the inner core and the cavity wall of the mold cavity, and then is cured at high temperature.

Described high temperature curing is to use 150 ℃ of high temperature to solidify the silver paste injected into the mold cavity for 30 minutes.

The mold includes an upper mold and a lower mold.

In step A5, the silver paste pre-impregnated for the element has a higher silver content than the silver paste injected into the mold in step B3.

The advantages of the solution of the present invention are that it can effectively solve the defects of the existing silver paste impregnation technology and dot silver paste stacking method, and has the advantages of being convenient for mass production, improving the ESR and life of the device, and the like.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments:

Accompanying drawing 1 is the schematic diagram of the capacitor of the present invention;

Accompanying drawing 2 is the schematic diagram of the capacitor of the present invention in another direction;

Accompanying drawing 3 is the schematic diagram of step B3;

Accompanying drawing 4 is another schematic diagram of step B3;

Accompanying drawing 5 is the schematic diagram of mould;

In the figure: 1-anode; 2-barrier glue; 3-cathode; 4-lead frame cathode workpiece; 5-element; 6-mold; 7-mold cavity; 8-upper mold; 9-lower mold.

Detailed ways

As shown in the figure, a solid electrolytic capacitor containing a silver paste cathode, the cathode 2 of the capacitor is an integrated silver-coated inner core, and the silver-coated inner core includes a multi-layered element 5 treated with pre-impregnated silver paste The stacked inner core also includes a silver paste solidified layer covering the outer wall of the inner core; the preparation method of the silver paste solidified layer is to first inject the silver paste into the mold 6 with the inner core and perform a high-frequency operation on the mold. Vibrate, and then solidify the silver paste in the mold at high temperature to form an integrated silver-coated inner core.

The preparation process of the capacitor includes an element processing process and an element stacking process;

The element processing procedure includes:

Step A1, forming an oxide film on the surface of the capacitor anode material so that it can be used as an oxide film dielectric material;

Step A2, using the barrier glue 3 to divide the capacitor cathode area and the anode area at the oxide film dielectric material;

Step A3, forming a conductive polymer as a solid electrolyte layer on the outer surface of the cathode region of the oxide film dielectric material;

Step A4, forming a conductive carbon cathode layer on the outer surface of the electrolyte layer;

Step A5, forming a conductive silver cathode layer on the outer surface of the conductive carbon cathode layer to shape the silver-containing conductive cathode;

The element stacking process includes:

Step B1, compressing each layer of elements to form an inner core with a laminated structure;

Step B2, connecting the anode 1 of the multi-piece element and the anode of the lead frame by welding;

Step B3, using a mold to inject silver paste to solidify the inner core into an integrated silver-coated inner core;

Step B4, encapsulating the cured integrated silver-coated inner core.

The method used in the step A5 includes the method of pre-impregnating the element with the conductive carbon cathode layer with a silver content of 45-65% silver paste;

The method used in the step B1 includes the method of placing the lead frame cathode workpiece 4 in the middle of the elements when stacking the elements layer by layer, thereby sandwiching the lead frame cathode workpiece in the middle of the stacked structure.

The mold is provided with a rectangular mold cavity 7, and the top of the mold is provided with an injection port;

When performing step B3, first place the inner core in the mold cavity, then inject silver paste with a silver content of 35-55% into the mold cavity from the top injection port of the mold, and use high-frequency vibration technology to vibrate the mold. The silver paste injected into the mold cavity can fill the gap between the elements and the space between the inner core and the cavity wall of the mold cavity, and then is cured at high temperature.

Described high temperature curing is to use 150 ℃ of high temperature to solidify the silver paste injected into the mold cavity for 30 minutes.

The mold includes an upper mold 8 and a lower mold 9 .

In step A5, the silver paste pre-impregnated for the element has a higher silver content than the silver paste injected into the mold in step B3.

Example:

Pre-impregnate the elements with the conductive carbon cathode layer with a silver content of 65% silver paste, and then sandwich the lead frame cathodes according to the process requirements to stack the elements layer by layer to form a laminated structure. Place it in a rectangular mold cavity. After the mold is closed, inject silver paste with a silver content of 55% into the mold cavity from the top injection port. Use high-frequency vibration technology to fill the silver paste between the elements and between the core and the mold. The space between the four interfaces is cured at a high temperature of 150°C for 30 minutes; the core that has been cured with the silver paste is taken out and packaged.

The high temperature assessment data of the above monolithic capacitor components are shown in the following table:

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Claims (3)

1. a solid electrolytic capacitor comprising a silver paste cathode, characterized in that: the cathode of the capacitor is an integrated silver-coated inner core, the silver-coated inner core comprises an inner core formed by stacking a plurality of layers of elements subjected to silver paste pre-impregnation treatment, and a silver paste curing layer coated on the outer wall of the inner core; the preparation method of the silver paste curing layer comprises the steps of firstly injecting silver paste into a die with an inner core arranged inside, carrying out high-frequency vibration on the die, and then curing the silver paste in the die at high temperature to form an integrated silver-coated inner core;

the preparation process of the capacitor comprises a prime processing process and a prime stacking process;

the element processing procedure comprises the following steps:

a1, forming an oxide film on the surface of the capacitor anode material to be used as an oxide film dielectric material;

a2, dividing a capacitance cathode area and an anode area at the position of an oxide film dielectric material by using barrier glue;

step A3, forming a conductive high molecular polymer on the outer surface of the cathode area of the oxide film dielectric material as a solid electrolyte layer;

step A4, forming a conductive carbon cathode layer on the outer surface of the electrolyte layer;

step A5, forming a conductive silver cathode layer on the outer surface of the conductive carbon cathode layer to form a silver-containing conductive cathode;

the prime stacking procedure comprises the following steps:

step B1, compacting the layers of the element to form an inner core with a laminated structure;

step B2, connecting the anodes of the multi-sheet elements and the anode of the lead frame by welding;

step B3, injecting silver paste by using a mould to solidify the inner core into an integrated silver-coated inner core;

step B4, packaging the cured integrated silver-coated inner core;

the method adopted in the step A5 comprises the steps of pre-soaking the elements of the conductive carbon cathode layer with silver paste with the silver content of 45-65%;

the method adopted in the step B1 comprises the steps of placing the lead frame cathode workpiece in the middle of the element when the element is stacked layer by layer, and clamping the lead frame cathode workpiece in the middle of the laminated structure;

a rectangular mold cavity is arranged in the mold, and an injection opening is formed in the top of the mold;

when the step B3 is executed, the inner core is placed in the mold cavity, silver paste with the silver content of 35-55% is injected into the mold cavity from an injection port at the top of the mold, the mold is vibrated by using a high-frequency vibration technology, so that the silver paste injected into the mold cavity can fill the gaps between the elements and the space between the inner core and the cavity wall of the mold cavity, and then high-temperature curing is carried out;

the silver paste pre-impregnated with the primordium in step a5 has a higher silver content than the silver paste injected into the mold in step B3.

2. The solid electrolytic capacitor comprising a silver paste cathode according to claim 1, wherein: the high-temperature curing is to cure the silver paste injected into the mold cavity for 30 minutes by using high temperature of 150 ℃.

3. The solid electrolytic capacitor comprising a silver paste cathode according to claim 1, wherein: the die comprises an upper die and a lower die.

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