Moisture-Barrier Capacitor Element Structure to Prevent Delamination
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Solution Overview
Problem
Capacitor elements with seal layers containing resin of high moisture permeability are prone to delamination due to water ingress, which expands upon heating, causing separation of the cathode layer from the anode plate.
Innovation Solution
Incorporating a cover layer with lower moisture permeability than the seal layer in the capacitor element, specifically at exposed portions of the anode plate, to prevent water entry and subsequent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal layer containing resin with high moisture permeability is used to cover the capacitor portion, then the seal layer provides effective sealing and protection, but moisture can easily penetrate into the anode plate causing delamination
Solution Approach 1:
The patent applies composite materials by combining the seal layer (providing sealing function) with a cover layer made of materials having lower moisture permeability than the seal layer. This composite structure allows the seal layer to maintain its sealing effectiveness while the cover layer blocks moisture penetration into the anode plate, thus resolving the contradiction between sealing performance and moisture resistance.
Solution Approach 2:
The cover layer acts as an intermediary between the seal layer and the anode plate. It is positioned to cover exposed portions of the anode plate at the edge of the capacitor portion, creating a protective barrier that prevents moisture from reaching the anode plate while allowing the seal layer to perform its sealing function. This intermediary structure resolves the moisture permeability issue without compromising sealing.
2Temperature
If the capacitor element is heated, then the evaporated water causes delamination of the cathode layer from the anode plate, but adding a cover layer increases structural complexity
Solution Approach 1:
The patent segments the protective structure into distinct functional layers: the seal layer for sealing and the cover layer for moisture protection. By dividing the protection function into separate layers with specific roles, the structure prevents moisture-related delamination during heating while maintaining clear functional boundaries, thus managing complexity through functional segmentation.
Solution Approach 2:
The cover layer is applied locally only to exposed portions of the anode plate at the edge of the capacitor portion, rather than covering the entire capacitor element. This localized application provides moisture protection precisely where needed (at edges where moisture can penetrate) without unnecessarily increasing the complexity of the overall structure, thus resolving the contradiction between heat resistance and structural simplicity.
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 cover layer effectively blocks water ingress, preventing delamination and maintaining the integrity of the capacitor element by reducing moisture-induced deterioration of electric characteristics.
Implementation Method 1
a cover layer with lower moisture permeability than the seal layer on either one or both of (1) at least a part of a space between an insulating member filled in the through-portions and a wall surface of the anode plate exposed to the through-portions and (2) at least a part of an exposed side surface of the anode plate at an edge of the capacitor portion
Implementation Method 2
When the capacitor element in that state receives heat, the capacitor element may cause delamination due to expansion of evaporated water
Data Source
AI summary
A capacitor element that includes: a capacitor portion including: an anode plate including a core portion and a porous portion on least one main surface of the core portion, a dielectric layer on a surface of the porous portion, and a cathode layer on a surface of the dielectric layer; a seal layer covering at least one main surface of the capacitor portion. A plurality of through-portions extend through the capacitor portion and the seal layer in a thickness direction. A cover layer with lower moisture permeability than the seal layer 20 is on either one or both of at least a part of a space between an insulating member filled in the through-portions and a wall surface of the anode plate exposed to the through-portions and at least a part of an exposed side surface of the anode plate at an edge of the capacitor portion.