Electrolytic Capacitor Pressure Valve with Arc-Shaped Thin Portion

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Solution Overview

Problem

The existing pressure valve and gas release valve configurations for electrolytic capacitors result in a higher number of parts, increasing costs without effectively improving the capacitor's lifetime, as reducing valve thickness to use a single valve compromises its durability.

Innovation Solution

A single pressure valve with a thin, gas-permeable actuation portion having a cross-like shape with protruding arcs is used, allowing gas release in normal conditions and breaking under increased pressure to actuate, while being designed to distribute stress effectively and prevent breakage during normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two valves (pressure valve and gas release valve) are used to release internal gas, then the reliability of gas release is improved, but the number of parts increases leading to higher cost

Engineering Contradiction:
Improvegas release reliabilityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the functions of the pressure valve and gas release valve into a single integrated valve structure. This unified valve performs both normal gas release and pressure relief functions, reducing the number of parts while maintaining the reliability of gas release under different operating conditions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single valve is designed with multi-functionality to handle both normal gas release operations and emergency pressure relief. The valve structure incorporates features that enable it to perform multiple functions that previously required separate components, thereby simplifying the overall device while preserving reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If the thickness of the single valve is decreased to enable gas release in normal use, then the gas release function is improved, but the valve becomes more prone to breakage reducing lifetime

Engineering Contradiction:
Improvegas release functionVSAvoidvalve lifetime
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The valve incorporates a thin portion with different thickness characteristics compared to other parts of the valve structure. This localized thinning allows the valve to be gas-permeable for normal gas release while the rest of the valve maintains sufficient thickness for strength and durability. The thin portion is specifically designed to be less likely to break under normal operating pressures.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The thin portion of the valve is made of gas-permeable material that allows gas to pass through during normal operation. This porous or gas-permeable characteristic enables the valve to perform its gas release function without requiring a complete opening, thereby maintaining structural integrity and resistance to breakage while still allowing effective gas release.

Inventive Principle:
Principle #31Porous materials

3Productivity

If the thin portion of the valve is made gas-permeable for normal gas release, then the gas release efficiency is improved, but the valve may break under increased pressure

Engineering Contradiction:
Improvegas release efficiencyVSAvoidvalve breakage resistance
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The valve structure features a thin portion with gas-permeable properties located at a specific position, while other portions maintain greater thickness for strength. This localized differentiation allows the gas-permeable region to handle normal gas release efficiently while thicker regions provide structural support and breakage resistance under pressure increases.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The outer edge of the thin portion is shaped with arcs protruding toward the inside, creating a rounded geometry. This curved design prevents stress concentration at sharp corners, distributing mechanical stresses more evenly across the thin portion. As a result, the gas-permeable thin portion can maintain its permeability function while having improved resistance to breakage under pressure conditions.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 configuration enhances the electrolytic capacitor's lifetime by reducing the number of parts while ensuring reliable gas release and preventing valve breakage, maintaining structural integrity and processability.

Implementation Method 1

the thin portion is made of gas-permeable material

Methodology Applied
Scientific EffectGas permeation: Permeation

Implementation Method 2

the outer edge of the thin portion is shaped to include a plurality of first arcs each protruding toward an inside of the thin portion... which prevents local concentration of a stress onto a corner of the outer edge of the thin portion

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 3

in the case of the rapid increase in internal pressure, a central portion of the thin portion is broken to actuate the pressure valve

Methodology Applied
Scientific EffectFracture mechanics: Fracture Mechanics

Data Source

PatentEP2869322B1Pressure valve for electrolytic capacitor, and electrolytic capacitor using same
Publication Date: 2018.03.14 NICHICON CORP
  • EP2869322B1 patent drawingFigure 1A~1B
  • EP2869322B1 patent drawingFigure 2
  • EP2869322B1 patent drawingFigure 3A~3D

AI summary

The lifetime of an electrolytic capacitor is improved while restraining the number of parts for releasing internal gas. A pressure valve 10 of the present invention is made of gas-permeable flexible material, and an actuation portion 11 and a supporter 12 are formed integrally with each other. The actuation portion 11 includes a thin portion 11a and a thick portion 11b provided in an outer region of the thin portion 11a and having a thickness greater than that of the thin portion 11a. When viewed from the direction of the thickness of the actuation portion 11, the thin portion 11a has a cross-like shape, and the outer edge of the thin portion 11a is shaped to include a plurality of first arcs a1 each protruding toward the inside of the thin portion 11a, and a plurality of second arcs a2 each protruding toward the outside of the thin portion 11a.