Winding Capacitor Electrode Foil with Separation Parts

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Solution Overview

Problem

Conventional electrode foils for winding capacitors face challenges in maintaining flexibility and stretchability during winding, leading to potential cracks in the core part and reduced electrostatic capacitance due to surface enlargement processes.

Innovation Solution

The introduction of separation parts on the electrode foil, which extend across the foil and are formed by cracking the surface enlarged parts, helps disperse bending stress, allowing for smoother winding and reducing the likelihood of core part cracks by distributing stress evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If surface enlargement process is performed to increase electrostatic capacitance, then the surface area of the dielectric film increases, but the flexibility and stretchability of the electrode foil decrease

Engineering Contradiction:
Improvesurface area of dielectric filmVSAvoidflexibility and stretchability of electrode foil
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The electrode foil is divided into surface enlarged parts (with dielectric film) and non-surface enlarged parts (without dielectric film). This segmentation allows the foil to maintain flexibility in the non-enlarged regions while achieving high capacitance in the enlarged regions, thereby resolving the contradiction between increased surface area and maintained flexibility.

Inventive Principle:
Principle #1Segmentation

2Reliability

If surface enlargement progresses to deeper parts to increase electrostatic capacitance, then the electrostatic capacitance increases, but the core part becomes thinner and more prone to cracking

Engineering Contradiction:
Improveelectrostatic capacitanceVSAvoidstrength of core part
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The electrode foil is segmented into surface enlarged parts and non-surface enlarged parts. The non-surface enlarged parts serve as a robust core structure that maintains strength and prevents cracking, while the surface enlarged parts provide high electrostatic capacitance. This segmentation resolves the contradiction between increased capacitance and maintained core strength.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If electrode foil with decreased flexibility is used for winding, then the winding process becomes difficult and may cause cracks, but maintaining flexibility reduces the electrostatic capacitance

Engineering Contradiction:
Improvewinding propertiesVSAvoidelectrostatic capacitance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The electrode foil is segmented such that non-surface enlarged parts provide flexibility and stretchability for easy winding, while surface enlarged parts provide high electrostatic capacitance. This segmentation allows the foil to be easily wound without cracking while maintaining high capacitance, resolving the contradiction between winding ease and capacitance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the electrode foil have different properties: non-surface enlarged parts have high flexibility for winding, while surface enlarged parts have high dielectric surface area for capacitance. This local differentiation of properties resolves the contradiction between winding ease and capacitance maintenance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3385968B1Electrode foil, winding capacitor, electrode foil manufacturing method, and winding capacitor manufacturing method
Publication Date: 2021.07.14 NIPPON CHEMI CON CORP
  • EP3385968B1 patent drawingFigure 1(a)~1(b)
  • EP3385968B1 patent drawingFigure 2
  • EP3385968B1 patent drawingFigure 3

AI summary

An electrode foil that progresses an enlargement of the surface area of a dielectric film and that barely causes cracks which would even break a core part at the time of winding, a winding capacitor obtained by winding the electrode foil, an electrode foil manufacturing method, and a winding capacitor manufacturing method are provided. An electrode foil 1 is formed of a belt-like foil, and has a surface enlarged part 3, a core part 2, and a plurality of separation parts 4. The surface enlarged part 3 is formed on the surface of the foil, and the core part 2 is a part remained when excluding the surface enlarged part 3 within the foil. The separation part 4 extends in a width direction of the belt in the surface enlarged part 3, dividing the surface enlarged part 3. The plurality of separation parts 4 share bending stress when the electrode foil 1 is wound, preventing concentration of stress.