Capacitor Housing Venting for High-Density Lifetime Stability

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Solution Overview

Problem

There is a high demand for volume-efficient capacitors with improved capacitance and lifetime, as high volume efficiency often results in reduced lifetime due to gas formation and mechanical stress, particularly in capacitors with sintered anodes.

Innovation Solution

Incorporating a gas dissipation element in the capacitor housing to reduce internal pressure non-destructively, combined with a sintered anode and specific electrolyte composition to suppress gas evolution, enhances mechanical stability and extends lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the volume efficiency of the capacitor is increased, then the capacitance per unit volume is improved, but the lifetime is reduced due to gas formation and mechanical stress

Engineering Contradiction:

Improvevolume efficiencyVSAvoidlifetime

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent extracts the harmful gas from the capacitor system by providing a gas outlet that allows gas to escape from the housing. This removes the accumulated gas pressure that would otherwise reduce the lifetime of high volume-efficient capacitors, thereby resolving the contradiction between improved volume efficiency and reduced lifetime.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The housing serves multiple functions: it contains the capacitive element, provides structural support, and acts as a pressure relief system through the gas outlet. This multi-functionality allows the capacitor to maintain high volume efficiency while simultaneously managing gas pressure to extend lifetime.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If a sintered anode is used to increase volume efficiency, then the capacitance density is improved, but the mechanical stability is reduced due to cracks and gas evolution

Engineering Contradiction:

Improvevolume efficiencyVSAvoidmechanical stability

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The gas outlet extracts and removes the gas evolved during capacitor operation, preventing gas accumulation that would exacerbate mechanical stress on the sintered anode. This allows the use of sintered anodes for high volume efficiency without compromising mechanical stability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The gas outlet provides a pre-established pressure relief mechanism that cushions the sintered anode against mechanical stress from gas evolution. By providing this protective feature in advance, the capacitor can use sintered anodes for improved volume efficiency while maintaining mechanical stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the housing is made airtight to improve reliability, then the protection against external factors is improved, but the gas pressure inside increases reducing lifetime

Engineering Contradiction:

Improveprotection against external factorsVSAvoidlifetime

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The gas outlet acts as an intermediary element in the housing that selectively allows gas to pass through while maintaining the airtight seal against external factors. This mediator enables the housing to simultaneously provide protection and gas pressure relief, resolving the contradiction between reliability and lifetime.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The gas outlet creates a controlled flexible opening in the otherwise airtight housing. This allows the housing to maintain its protective sealing function while incorporating a flexible gas release pathway, enabling both protection against external factors and management of internal gas pressure to extend lifetime.

Inventive Principle:

Principle #30Flexible shells and thin films

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

The solution achieves improved volume efficiency and extended lifetime by effectively managing gas pressure and reducing leakage current, particularly in capacitors with sintered anodes.

Implementation Method 1

a gas dissipation element (6) that is arranged in or above a through-hole (5) in the housing (3, 4) and that is configured for reducing a gas pressure inside the capacitor (1)

Methodology Applied

Scientific EffectGas pressure reduction: Depressurisation

Implementation Method 2

the anode (21) can be a so-called sintered anode... the capacitive element can be configured to store electric charges during operation of the capacitor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 3

the anode (21) has an oxide on its surface that provides an at least partial chemical and electrical separation between anode and electrolyte

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 4

a separator that is drenched with or soaked with the electrolyte may be arranged between anode and cathode

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS20250385050A1Capacitor and method of forming a capacitor

Publication Date: 2025.12.18 TDK ELECTRONICS AG

AI summary

A capacitor includes a capacitive element arranged in a housing, wherein in or on the housing a gas dissipation element is arranged and/or wherein the capacitor has an electrolyte that comprises an organic acid having a pka of 4.1 or higher and/or wherein the capacitor has an OMS of 20% or higher.