Hybrid Capacitor Pre-Coated Separator for Low ESR

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Solution Overview

Problem

Existing methods for forming hybrid capacitors are limited in size and configuration, particularly for axial capacitors, due to challenges with conductive polymer impregnation and diffusion, leading to poor efficiency and high Equivalent Series Resistance (ESR).

Innovation Solution

A method involving pre-treatment of anodes, cathodes, and separators with conductive polymer coatings or impregnation before winding, allowing for improved polymer distribution and liquid electrolyte flow, enabling the formation of capacitors with enhanced performance and flexibility in design, including axial configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pre-formed conductive polymer slurry is used to impregnate the interstitial spaces of the capacitor winding, then the manufacturing complexity is reduced compared to in-situ polymerization, but the diffusion rate and efficiency are limited, restricting the capacitor size to small dimensions only

Engineering Contradiction:

Improvemanufacturing process complexityVSAvoidcapacitor size

Core Design Contradiction:

Device complexityVSLength of stationary object

Solution Approach 1:

The separator is pre-coated with conductive polymer before the winding process. This preliminary action ensures that the conductive polymer is already in place to facilitate efficient ion transport, eliminating the need for post-assembly impregnation and enabling large capacitor sizes without diffusion limitations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The separator is made porous and pre-coated with conductive polymer, creating a three-dimensional conductive network within the interstitial spaces. This porous structure allows efficient ion transport throughout the entire capacitor volume, enabling large capacitor sizes while maintaining low ESR

Inventive Principle:

Principle #31Porous materials

2Ease of manufacture

If the bottom tab is dipped in the polymer precursor or polymer slurry during axial capacitor manufacturing, then the conductive polymer can be applied to the working element, but the tab becomes polymer coated which causes problems with subsequent processing and voltage application

Engineering Contradiction:

Improvepolymer applicationVSAvoidsubsequent processing

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The conductive polymer coating is extracted from the tab area and applied only to the separator. This separation ensures that the tabs remain free of polymer coating, enabling proper electrical contact and subsequent processing without the complications of polymer-coated tabs

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The separator is selectively coated with conductive polymer while the tabs remain uncoated. This local differentiation ensures that the polymer is applied only where needed for ion transport, while the tabs maintain their electrical conductivity and processing compatibility

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If in-situ polymerization of monomer is used to form conductive polymer in the interstitial areas, then the conductive polymer coverage can be improved, but the method is complex with contamination issues and poor process reliability

Engineering Contradiction:

Improveconductive polymer coverageVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The separator is pre-coated with conductive polymer before assembly, eliminating the need for in-situ polymerization. This preliminary coating ensures complete and uniform conductive polymer coverage in all interstitial spaces without the complexity and contamination risks of monomer polymerization

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of using complex in-situ polymerization processes with monomers and oxidizers that require precise control and contamination management, the invention uses simple pre-formed conductive polymer coatings that can be applied straightforwardly to the separator before assembly

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach eliminates size restrictions and increases volumetric efficiency, achieving low ESR and high capacitance in capacitors of various designs, including axial and radial configurations, with improved reproducibility and scalability.

Implementation Method 1

a conductive separator, wherein the conductive separator comprises a separator and a conductive polymer coating on the separator

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

by diffusion of pre-formed polymer slurry into the interstitial areas of the wound interleaved structure

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS10777361B2Hybrid capacitor and method of manufacturing a capacitor

Publication Date: 2020.09.15 KEMET ELECTRONICS CORP

AI summary

An improved capacitor is described herein. The capacitor comprises a working element wherein the working element comprises an anode comprising a dielectric thereon and an anode conductive polymer layer on the dielectric. The capacitor also includes a cathode comprising a cathode conductive polymer layer and a conductive separator between the anode and said cathode. An anode lead is in electrical contact with the anode and a cathode lead is in electrical contact with the cathode.